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Sample records for blood oxygen saturation

  1. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Energy Technology Data Exchange (ETDEWEB)

    Kyriacou, P A [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Shafqat, K [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Pal, S K [St Andrew' s Centre for Plastic Surgery and Burns, Broomfield Hospital, Chelmsford, CM1 7ET (United Kingdom)

    2007-10-15

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO{sub 2}) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO{sub 2}) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO{sub 2} sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures

  2. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Science.gov (United States)

    Kyriacou, P. A.; Shafqat, K.; Pal, S. K.

    2007-10-01

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO2) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO2) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO2 sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures. Both pulse

  3. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    International Nuclear Information System (INIS)

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO2) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO2) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO2 sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures. Both pulse

  4. Photoacoustic assessment of oxygen saturation: effect of red blood cell aggregation

    Science.gov (United States)

    Hysi, Eno; Saha, Ratan K.; Kolios, Michael C.

    2013-03-01

    The simultaneous photoacoustic assessment of oxygen saturation and red blood cell aggregation is presented. Aggregation was induced on porcine red blood cells using Dextran-70 at multiple hematocrit levels. Samples were exposed to 750 nm and 1064 nm for each hematocrit and aggregate size in order to compute the oxygen saturation. As the size of the aggregate increased, the photoacoustic signal amplitude increased monotonically. The same trend was observed for increasing hematocrit at each aggregation level. The oxygen saturation of aggregated samples was 30% higher than non-aggregated samples at each hematocrit level. This suggests that the presence of red blood cell aggregates impairs the release of oxygen to the surrounding environment. Such a result has important implications for detecting red blood cell aggregation non-invasively and making clinical decisions based on the simulatenous assessment of oxygen saturation.

  5. Arterial blood gas analysis or oxygen saturation in the assessment of acute asthma?

    OpenAIRE

    Carruthers, D M; Harrison, B. D.

    1995-01-01

    BACKGROUND--A study was undertaken to determine if arterial blood gas estimation is always necessary in the assessment of patients presenting to hospital with acute severe asthma, or whether oxygen saturation as measured by pulse oximetry is a reliable screening test for predicting those in respiratory failure. METHODS--A prospective study was conducted in a specialist respiratory medical unit. Arterial blood gas tensions and pulse oximetry were measured in 89 consecutive patients admitted wi...

  6. Noninvasive functional photoacoustic tomography of blood-oxygen saturation in the brain

    Science.gov (United States)

    Wang, Xueding; Ku, Geng; Xie, Xueyi; Wang, Yiwen; Stoica, George; Wang, Lihong V.

    2004-07-01

    Since optical contrast is sensitive to functional parameters, including the hemoglobin oxygen saturation and the total concentration of hemoglobin, imaging based on optical contrast has been widely employed for the real-time monitoring of tissue oxygen consumption and hemodynamics in biological tissues. However, due to the overwhelming scattering of light in tissues, traditional optical imaging modalities cannot provide satisfactory spatial resolution. Functional photoacoustic tomography is a novel technique that combines high optical contrast and high ultrasonic resolution. Here, we present our study of a laser-based photoacoustic technique that, for the first time to our knowledge, monitors blood oxygenation in the rat brain in vivo. The cerebral blood oxygenation in the rat brain was imaged by photoacoustic detection at two wavelengths. The change in the hemoglobin oxygen saturation in the brain vessels as a result of the alternation from hyperoxia status to hypoxia status was visualized successfully with satisfactory spatial resolution. This work demonstrates that photoacoustic technique, based on the spectroscopic absorption of oxy- and deoxy-hemoglobin, can provide accurate functional imaging of cerebral blood oxygenation in the small-animal brain non-invasively with the skin and skull intact.

  7. MRI-based blood oxygen saturation measurements in infants and children with congenital heart disease

    International Nuclear Information System (INIS)

    Background: Vessel oxygen saturation can be determined with MR oximetry using an in vivo measurement of signal decay (T2) and the calibration curve relating T2 to blood oxygen saturation (%HbO2), where: 1/T2=1/T2O+K (1-%HbO2/100)2 and K is a constant parameter which correlates with measured fibrinogen levels. The ability to noninvasively measure %HbO2 in cardiac chambers and vessels has enormous potential in children with congenital heart disease (CHD). Objective: The purpose of the study was to prospectively characterize the T2-%HbO2 relationship in infants where T2-%HbO2 is the realtionship between T2 and %HbO2 (blood oxygen saturation) expressed by the equation given above, and to determine whether adult values for K and T2O (where T2O is the T2 of fully oxygenated blood) can be extrapolated to pediatric patients with CHD. A second objective was to apply this method to calculate the %HbO2 in vivo using MR imaging in infants with CHD. Materials and methods: Fifteen patients with CHD undergoing cardiac catheterization (9 male; 6 female), median age 8 months, were recruited for the calibration study. T2O and K were measured directly from blood samples, compared with the values estimated from adult population statistics, and plotted against hematocrit and fibrinogen, respectively. In four studies of infants with CHD, T2 measurements were converted to %HbO2 using the calibration curve. Results: The T2-%HbO2 relationship in infants correlated with the adult calibration statistics (1/T2O vs. hematocrit, r=0.77; K vs. fibrinogen, r=0.61). Our initial in vivo studies demonstrated that the MR oximetry reflected the expected oxygen saturations. Conclusion: Adult values for T2-%HbO2 calibration can be used to measure blood oxygen saturation in vivo in children with CHD. (orig.)

  8. Measurement of oxygen saturation in venous blood by dynamic near IR spectroscopy

    Science.gov (United States)

    Nitzan, Meir; Babchenko, Anatoly; Khanokh, Boris; Taitelbaum, Haim

    2000-04-01

    A method for the measurement of oxygen saturation in the venous blood, SvO2, based on optical measurements of light absorption in the infrared region is presented. The method consists of applying relatively low external pressure of 25 mm Hg on the forearm, thereby increasing the venous blood volume in the tissue, and comparing the light absorption before and after the external pressure application. SvO2 has been determined from light absorption measurements in two wavelengths, before and after the pressure application, using a formula derived for two adjacent wavelengths. The method has been applied to the hands and fingers of 17 healthy male subjects, using wavelengths of 767 and 811 nm. SaO2, the oxygen saturation for arterial blood, was also obtained from photoplethysmographic measurements in these two wavelengths (pulse oximetry) using the same formula. The mean (+/- SD) value of SaO2 was 94.5%(+/- 3.0). The mean value of SvO2 was 86.2%(+/- 4.1) for the finger and 80.0%(+/- 8.2) for the hand. These SvO2 values are reasonable for the finger and the hand where arterio-venous anastomoses exist. The method enables the measurement of SvO2 in the limbs, a parameter which is related to tissue blood flow and oxygen consumption.

  9. Peripheral venous blood oxygen saturation can be non-invasively estimated using photoplethysmography.

    Science.gov (United States)

    Khan, Musabbir; Pretty, Christopher G; Amies, Alexander C; Elliott, Rodney B; Suhaimi, Fatanah M; Shaw, Geoffrey M; Chase, J Geoffrey

    2015-08-01

    Measurement of peripheral venous oxygen saturation (SvO2) is currently performed using invasive catheters or direct blood draw. The purpose of this study was to non-invasively determine SvO2 using a variation of pulse oximetry techniques. Artificial respiration-like modulations applied to the peripheral vascular system were used to infer regional SvO2 using photoplethysmography (PPG) sensors. To achieve this modulation, an artificial pulse generating system (APG) was developed to generate controlled, superficial perturbations on the finger using a pneumatic digit cuff. These low pressure and low frequency modulations affect blood volumes in veins to a much greater extent than arteries due to significant arterial-venous compliance differences. Ten healthy human volunteers were recruited for proof-ofconcept testing. The APG was set at a modulation frequency of 0.2 Hz (12 bpm) and 45-50 mmHg compression pressure. Initial analysis showed that induced blood volume changes in the venous compartment could be detected by PPG. Estimated arterial oxygen saturation (97% [IQR=96.1%-97.4%]) matches published values (95%-99%). Estimated venous oxygen saturation (93.2% [IQR=91.-93.9%]) agrees with reported ranges (92%-95%) measured in peripheral regions. The median difference between the two saturations was 3.6%, while the difference between paired measurements in each subject was statistically significant (p=0.002). These results demonstrate the feasibility of this method for real-time, low cost, non-invasive estimation of SvO2. Further validation of this method is warranted. PMID:26737758

  10. Comparison of Neonatal Arterial Blood Oxygen Saturation Rate Immediately After Birth in Normal and Elective Cesarean Delivery

    OpenAIRE

    Mahmoodi Fatemeh; Mobaraki Asieh; Mahmoodi Zainab; Najar Shahnaz; Haghighi Mohammad hosein; Borzoueisileh Sajad; Ebrahimpour Soheil

    2016-01-01

    Objective: Ninety percent of neonates pass the transition from fetal life to outside uterus successfully, and only 1% needs intensive support for survival. The quantity of oxygen saturation immediately after birth shows the need for resuscitation immediately after birth. The present research was carried out with the objective of comparing saturation rate of arterial blood hypoxia in neonates born with normal vaginal delivery and cesarean method. Materials and Methods: 220 neonates bo...

  11. T2 and T2* measurements of fetal brain oxygenation during hypoxia with MRI at 3T: correlation with fetal arterial blood oxygen saturation

    International Nuclear Information System (INIS)

    The purpose of this prospective study was to determine the oxygen saturation of blood in the fetal brain based on T2 and T2* measurements in a fetal sheep model. Five sheep fetuses were investigated during normoxia and hypoxia by 3T MRI. Multi-echo gradient-echo and turbo-spin-echo sequences were performed on the fetal brain. MR-determined oxygen saturation (MR-sO2) of blood in the fetal brain was calculated based on T2 and T2* values. Fetal arterial blood oxygen saturation (blood-sO2) was measured during the two experimental phases. The slope of MR-sO2 as a function of blood-sO2 was estimated and tested for compatibility using the one-sample t-test. During normoxia, mean values for carotid blood oxygen saturation were 67%, 83 ms for T2*, 202 ms for T2 and 96% for MR-sO2. During hypoxia, arterial blood oxygen saturation, T2* and calculated MR-sO2 decreased to 22%, 64 ms, and 68% respectively. The one-sample t-test revealed the slope to be significantly different from 0(T=5.023, df=4, P=0.007). It is feasible to perform quantitative T2 and T2* measurements in the fetal brain. MR-sO2 and fetal arterial blood oxygen saturation correlated significantly. However, based on these data a reliable quantification of fetal brain tissue oxygenation is not possible. (orig.)

  12. T2 and T2* measurements of fetal brain oxygenation during hypoxia with MRI at 3T: correlation with fetal arterial blood oxygen saturation

    Energy Technology Data Exchange (ETDEWEB)

    Wedegaertner, Ulrike; Adam, Gerhard [Universitaetsklinikum Hamburg-Eppendorf, Department of Diagnostic and Interventional Radiology, Hamburg (Germany); Kooijman, Hendrik [Philips Medical Systems, Best (Netherlands); Andreas, Thomas; Beindorff, Nicola; Hecher, Kurt [University Hospital Hamburg-Eppendorf, Department of Obstetrics and Prenatal Medicine, Hamburg (Germany)

    2010-01-15

    The purpose of this prospective study was to determine the oxygen saturation of blood in the fetal brain based on T2 and T2* measurements in a fetal sheep model. Five sheep fetuses were investigated during normoxia and hypoxia by 3T MRI. Multi-echo gradient-echo and turbo-spin-echo sequences were performed on the fetal brain. MR-determined oxygen saturation (MR-sO{sub 2}) of blood in the fetal brain was calculated based on T2 and T2* values. Fetal arterial blood oxygen saturation (blood-sO{sub 2}) was measured during the two experimental phases. The slope of MR-sO{sub 2} as a function of blood-sO{sub 2} was estimated and tested for compatibility using the one-sample t-test. During normoxia, mean values for carotid blood oxygen saturation were 67%, 83 ms for T2*, 202 ms for T2 and 96% for MR-sO{sub 2}. During hypoxia, arterial blood oxygen saturation, T2* and calculated MR-sO{sub 2} decreased to 22%, 64 ms, and 68% respectively. The one-sample t-test revealed the slope to be significantly different from 0(T=5.023, df=4, P=0.007). It is feasible to perform quantitative T2 and T2* measurements in the fetal brain. MR-sO{sub 2} and fetal arterial blood oxygen saturation correlated significantly. However, based on these data a reliable quantification of fetal brain tissue oxygenation is not possible. (orig.)

  13. Investigating tissue respiration and skin microhaemocirculation under adaptive changes and the synchronization of blood flow and oxygen saturation rhythms

    International Nuclear Information System (INIS)

    Multi-functional laser non-invasive diagnostic systems allow the study of a number of microcirculatory parameters, including index of blood microcirculation (Im) (by laser Doppler flowmetry, LDF) and oxygen saturation (StO2) of skin tissue (by tissue reflectance oximetry, TRO). This research aimed to use such a system to investigate the synchronization of microvascular blood flow and oxygen saturation rhythms under normal and adaptive change conditions. Studies were conducted on eight healthy volunteers of 21–49 years. These volunteers were observed between one and six months, totalling 422 basic tests (3 min each). Measurements were performed on the palmar surface of the right middle finger and the lower forearm's medial surface. Rhythmic oscillations of LDF and TRO were studied using wavelet analysis. Combined tissue oxygen consumption data for all volunteers during ‘adaptive changes’ increased relative to normal conditions with and without arteriovenous anastomoses. Data analysis revealed resonance and synchronized rhythms in microvascular blood flow and oxygen saturation as an adaptive change in myogenic oscillation (vasomotion) resulting from exercise and possibly psychoemotional stress. Synchronization of myogenic rhythms during adaptive changes may lead to increased oxygen consumption as a result of increased microvascular blood flow velocity. (paper)

  14. Measuring tissue oxygen saturation using NIR spectroscopy

    Science.gov (United States)

    Sircan-Kucuksayan, Aslinur; Uyuklu, Mehmet; Canpolat, Murat

    2014-05-01

    Tissue oxygen saturation (StO2) is known quite useful parameter for medical applications. A spectroscopic method has been developed to diagnose pathologic tissues due to lack of normal blood circulation by measuring tissue oxygen saturation. In the study, human blood samples with different level of oxygen saturations have been prepared and spectra were taken using an optical fiber probe to investigate correlation between the oxygen saturations and the spectra. The experimental set up for the spectroscopic measurements was consists of a miniature NIR light spectrometer, an optical fiber probe, a halogen-tungsten light source and a laptop. A linear correlation between the oxygen saturation of the blood samples and the ratio of the light of wavelengths 660 nm to 790 nm has been found from the spectra. Then, oxygen saturations of the blood samples were estimated from the spectroscopic measurements within an error of 2.9%. Furthermore, it has been shown that the linear dependence between the ratio and the oxygen saturation of the blood samples was valid for the blood samples with different hematocrits. Tissue oxygen saturation has been estimated from the spectroscopic measurements were taken from the fingers of healthy volunteers using the correlation between the spectra and blood oxygen saturation. The tissue StO2 measured was 80% as expected. The technique developed to measure tissue oxygen saturation has potential to diagnose premalignant tissues, follow up prognosis of cancerous tissues, and evaluation of ischemia reperfusion tissues.

  15. Segregation analysis of blood oxygen saturation in broilers suggests a major gene influence on ascites.

    Science.gov (United States)

    Navarro, P; Visscher, P M; Chatziplis, D; Koerhuis, A N M; Haley, C S

    2006-12-01

    1. Blood oxygen saturation (SaO) is a potential indicator trait for resistance to ascites in chickens. 2. The objective of the study was to investigate the genetic architecture of SaO in a meat-type chicken line reared in commercial conditions. 3. Data were collected over 15 generations of selection and were divided into two data sets on the basis of a change in recording age from 6 to 5 weeks of age, approximately halfway through the period. The resulting pedigrees comprised in excess of 90,000 birds each and, on average, 12% of these birds had SaO records. 4. Segregation analyses of SaO were carried out assuming a mixed inheritance model that included a major locus segregating in a polygenic background. 5. The analyses suggest that a major gene is involved in the genetic control of SaO in this line. The putative gene acts in a dominant fashion and has an additive effect of around 0.90 sigma(p), equivalent to a predicted difference in SaO between the two homozygous classes of more than 10%. The frequency of the allele that increases SaO changed from 0.53 to 0.65 from the first to the second set of data, consistent with selection on SaO scores. 6. Using estimated genotype probabilities at the putative major locus, we inferred that it acts in an overdominant fashion on body weight and fleshing score. If the low SaO allele leads to susceptibility to ascites, its combined effects are consistent with it being maintained in the population by a balance of natural selection on fitness nad artificial selection on growth and carcase traits. 7. Even with selection on both SaO and growth traits, the combined genotypic effects would make it difficult to remove the unfavourable low-SaO allele by means of traditional selection without the use of genetic markers. PMID:17190674

  16. Regulation of nitrite transport in red blood cells by hemoglobin oxygen fractional saturation

    OpenAIRE

    Vitturi, Dario A; Teng, Xinjun; Toledo, José C.; Matalon, Sadis; Lancaster, Jack R.; Patel, Rakesh P.

    2009-01-01

    Allosteric regulation of nitrite reduction by deoxyhemoglobin has been proposed to mediate nitric oxide (NO) formation during hypoxia. Nitrite is predominantly an anion at physiological pH, raising questions about the mechanism by which it enters the red blood cell (RBC) and whether this is regulated and coupled to deoxyhemoglobin-mediated reduction. We tested the hypothesis that nitrite transport by RBCs is regulated by fractional saturation. Using human RBCs, nitrite consumption was faster ...

  17. High-frequency photoacoustic imaging of erythrocyte aggregation and oxygen saturation: probing hemodynamic relations under pulsatile blood flow

    Science.gov (United States)

    Bok, Tae-Hoon; Hysi, Eno; Kolios, Michael C.

    2015-03-01

    In this paper, we investigate the feasibility of high-frequency photoacoustic (PA) imaging to study the shear rate dependent relationship between red blood cell (RBC) aggregation and oxygen saturation (SO2) in a simulated blood flow system. The PA signal amplitude increased during the formation of aggregates and cyclically varied at intervals corresponding to the beat rate (30, 60, 120, 180 and 240 bpm) for all optical wavelengths of illumination (750 and 850 nm).The SO2 also cyclically varied in phase with the PA signal amplitude for all beat rates. In addition, the mean blood flow velocity cyclically varied at the same interval of beat rate, and the shear rate (i.e. the radial gradient of flow velocity) also cyclically varied. On the other hand, the phase of the cyclic variation in the shear rate was reversed compared to that in the PA signal amplitude. This study indicates that RBC aggregation induced by periodic changes in the shear rate can be correlated with the SO2 under pulsatile blood flow. Furthermore, PA imaging of flowing blood may be capable of providing a new biomarker for the clinical application in terms of monitoring blood viscosity, oxygen delivery and their correlation.

  18. Simultaneous assessment of red blood cell aggregation and oxygen saturation under pulsatile flow using high-frequency photoacoustics

    Science.gov (United States)

    Bok, Tae-Hoon; Hysi, Eno; Kolios, Michael C.

    2016-01-01

    We investigate the feasibility of photoacoustic (PA) imaging for assessing the correlation between red blood cell (RBC) aggregation and the oxygen saturation (sO2) in a simulated pulsatile blood flow system. For the 750 and 850 nm illuminations, the PA amplitude (PAA) increased and decreased as the mean blood flow velocity decreased and increased, respectively, at all beat rates (60, 120 and 180 bpm). The sO2 also cyclically varied, in phase with the PAA for all beat rates. However, the linear correlation between the sO2 and the PAA at 850 nm was stronger than that at 750 nm. These results suggest that the sO2 can be correlated with RBC aggregation induced by decreased mean shear rate in pulsatile flow, and that the correlation is dependent on the optical wavelength. The hemodynamic properties of blood flow assessed by PA imaging may be used to provide a new biomarker for simultaneous monitoring blood viscosity related to RBC aggregation, oxygen delivery related to the sO2 and their clinical correlation.

  19. Simultaneous assessment of red blood cell aggregation and oxygen saturation under pulsatile flow using high-frequency photoacoustics.

    Science.gov (United States)

    Bok, Tae-Hoon; Hysi, Eno; Kolios, Michael C

    2016-07-01

    We investigate the feasibility of photoacoustic (PA) imaging for assessing the correlation between red blood cell (RBC) aggregation and the oxygen saturation (sO2) in a simulated pulsatile blood flow system. For the 750 and 850 nm illuminations, the PA amplitude (PAA) increased and decreased as the mean blood flow velocity decreased and increased, respectively, at all beat rates (60, 120 and 180 bpm). The sO2 also cyclically varied, in phase with the PAA for all beat rates. However, the linear correlation between the sO2 and the PAA at 850 nm was stronger than that at 750 nm. These results suggest that the sO2 can be correlated with RBC aggregation induced by decreased mean shear rate in pulsatile flow, and that the correlation is dependent on the optical wavelength. The hemodynamic properties of blood flow assessed by PA imaging may be used to provide a new biomarker for simultaneous monitoring blood viscosity related to RBC aggregation, oxygen delivery related to the sO2 and their clinical correlation. PMID:27446705

  20. Comparison of Neonatal Arterial Blood Oxygen Saturation Rate Immediately After Birth in Normal and Elective Cesarean Delivery

    Directory of Open Access Journals (Sweden)

    Mahmoodi Fatemeh

    2016-01-01

    Full Text Available Objective: Ninety percent of neonates pass the transition from fetal life to outside uterus successfully, and only 1% needs intensive support for survival. The quantity of oxygen saturation immediately after birth shows the need for resuscitation immediately after birth. The present research was carried out with the objective of comparing saturation rate of arterial blood hypoxia in neonates born with normal vaginal delivery and cesarean method. Materials and Methods: 220 neonates born with elective cesarean section and normal delivery were studied in an analytical-descriptive study. Demographic questionnaire was completed. Then a pulse oxymeter with its sensor fixed on the right wrist of the neonates was used. Heart rate was recorded and the level of oxygen saturation (SaO2 under 90% was considered as hypoxia. To compare the quantitative and qualitative variable between the two groups, paired t test and chi-square test was used, respectively. Pearson correlation test was used to study the correlation between the variables. Results: The age range of mothers was 16-38 years. The mothers’ average age, gestational age and neonates’ weight were not significantly different between groups. The average SaO2 in minutes 1, 3 and 5 was 72%, 81% and 89%, respectively in vaginal delivery, which showed a significant difference compared to cesarean neonates with average of 65%, 75% and 83%, respectively. No significant difference was observed after10 minutes. Also there were not significant statistical correlation between mothers age, number of pregnancies, sex and weight of neonate with SaO2 of arterial blood after 1, 3, 5 and 10 minutes after birth. Conclusion: With respect to the results of the present research SaO2 was higher in neonates of vaginal delivery in comparison to cesarean neonates. Encouraging mothers to delivery vaginally and also using aid-oxygen is proposed for the cesarean neonates at birth.

  1. The Influence of High-Altitude Acclimatization on Ventilatory and Blood Oxygen Saturation Responses During Normoxic and Hypoxic Testing

    Directory of Open Access Journals (Sweden)

    Ušaj1 Anton

    2016-04-01

    V˙E${\\dot V_E}$, SaO2, blood pH and Pco2 were measured at a similar absolute exercise intensity of 180 W in NOR and HYP conditions. Seven experienced alpinists (mean ± SD: age: 50 ± 6 yrs; body mass: 76 ± 5 kg; body height: 175 ± 8 cm volunteered to participate in this study after they had reached the summit of Gasherbrum II and Ama Dablam. They had therefore experienced the limitations of their acclimatization. Individual differences of PLT between values reached after and before the expedition (∆PLT correlated (r = 0.98, p = 0.01 with differences of SaO2 (∆SaO2 in HYP, and differences of PVT (∆PVT correlated (r = -0.83, p = 0.02 with differences of V˙E(ΔV˙E${\\dot V_E}\\left( {\\Delta {{\\dot V}_E}} \\right$ in HYP. The results suggest that the acclimatization may not have an equivocal and simple influence on the performance in hypoxia: enhanced blood oxygen saturation may be accompanied by increased endurance only, when the increase exceeded 2-3%, but enhanced ventilation, when increased more than 10 l/min in HYP, could detrimentally influence endurance.

  2. In vivo MRI measurement of fetal blood oxygen saturation in cardiac ventricles of fetal sheep: a feasibility study.

    Science.gov (United States)

    Wedegärtner, Ulrike; Kooijman, Hendrik; Yamamura, Jin; Frisch, Michael; Weber, Christoph; Buchert, Ralph; Huff, Anna; Hecher, Kurt; Adam, Gerhard

    2010-07-01

    The purpose of this study was to assess the feasibility to determine fetal blood oxygen saturation (sO(2)) with T(2)-weighted MR sequences using a fetal sheep model. T(2) measurements were performed on a 1.5-T scanner using a T(2) preparation pulse in combination with a three-dimensional balanced steady-state free precession sequence repeated at different echo times. Eight sheep fetuses were examined during a control, hypoxic, and recovery phase to perform T(2)-weighted scans of the fetal blood in the heart. Signal intensities in the left and right ventricle were measured to calculate the MR blood sO(2). During each phase, fetal carotid artery sO(2) was directly measured and correlated with MR sO(2). A Bland-Altman plot was performed. Fetal carotid artery sO(2) was 69% sO(2) during control, 16% sO(2) during hypoxemia, and 67% sO(2) during recovery. Mean values of the MR sO(2) were 49% sO(2) and 40% sO(2) for control, 6% sO(2) and 3% sO(2) for hypoxemia, and 51% sO(2) and 43% sO(2) for recovery in left ventricle and right ventricle, respectively. Mean values of fetal carotid artery sO(2) and MR sO(2) were highly correlated (left ventricle: r = 0.87, right ventricle: r = 0.89). According to the Bland-Altman plot, MR sO(2) was lower compared to fetal carotid artery sO(2) (left ventricle: 15%, right ventricle: 20%). Based on our preliminary results, it seems to be possible to assess fetal sO(2) with MR oximetry. PMID:20572133

  3. Seven-Day Mortality Can Be Predicted in Medical Patients by Blood Pressure, Age, Respiratory Rate, Loss of Independence, and Peripheral Oxygen Saturation (the PARIS Score)

    DEFF Research Database (Denmark)

    Brabrand, Mikkel; Lassen, Annmarie Touborg; Knudsen, Torben;

    2015-01-01

    . The outcome was defined as seven-day all-cause mortality. 76 patients (2.5%) met the endpoint in the development cohort, 57 (2.0%) in the first validation cohort, and 111 (4.3%) in the second. Systolic blood Pressure, Age, Respiratory rate, loss of Independence, and peripheral oxygen Saturation were...

  4. Comparison of pulseoximetry oxygen saturation and arterial oxygen saturation in open heart intensive care unit

    Directory of Open Access Journals (Sweden)

    Alireza Mahoori

    2013-08-01

    Full Text Available Background: Pulseoximetry is widely used in the critical care setting, currently used to guide therapeutic interventions. Few studies have evaluated the accuracy of SPO2 (puls-eoximetry oxygen saturation in intensive care unit after cardiac surgery. Our objective was to compare pulseoximetry with arterial oxygen saturation (SaO2 during clinical routine in such patients, and to examine the effect of mild acidosis on this relationship.Methods: In an observational prospective study 80 patients were evaluated in intensive care unit after cardiac surgery. SPO2 was recorded and compared with SaO2 obtained by blood gas analysis. One or serial arterial blood gas analyses (ABGs were performed via a radial artery line while a reliable pulseoximeter signal was present. One hundred thirty seven samples were collected and for each blood gas analyses, SaO2 and SPO2 we recorded.Results: O2 saturation as a marker of peripheral perfusion was measured by Pulseoxim-etry (SPO2. The mean difference between arterial oxygen saturation and pulseoximetry oxygen saturation was 0.12%±1.6%. A total of 137 paired readings demonstrated good correlation (r=0.754; P<0.0001 between changes in SPO2 and those in SaO2 in samples with normal hemoglobin. Also in forty seven samples with mild acidosis, paired readings demonstrated good correlation (r=0.799; P<0.0001 and the mean difference between SaO2 and SPO2 was 0.05%±1.5%.Conclusion: Data showed that in patients with stable hemodynamic and good signal quality, changes in pulseoximetry oxygen saturation reliably predict equivalent changes in arterial oxygen saturation. Mild acidosis doesn’t alter the relation between SPO2 and SaO2 to any clinically important extent. In conclusion, the pulse oximeter is useful to monitor oxygen saturation in patients with stable hemodynamic.

  5. Blood gases and oxygen saturation response to active cycle of breathing techniques in COPD patients during phase I of cardiac rehabilitation

    International Nuclear Information System (INIS)

    Objective: To determine the effectiveness of active cycle of breathing techniques (ACBTs) on arterial blood gases (ABG), oxygen saturation and other vitals including chest expansion, heart rate, and respiratory rate in COPD patients during phase I of cardiac rehabilitation program after open heart surgery. Methodology: In this experimental study, sample size chosen was 100 patients, randomly divided into experimental (n=50) and control (n=50) groups. Pre-test values of ABG, oxygen saturation, chest expansion, respiratory rate, and heart rate of the participants were taken. Then, conventional physical therapy including spirometry was performed 2 hourly by the control group whereas the experimental group performed ACBTs along with spirometry twice a day for a period of one week. Participants were re-assessed after one week treatment. Results: There was highly significant difference (p<0.01) in pre-test and post-test values of PCO/sub 2/ and oxygen saturation in experimental group as compared to control group. The results of bicarbonate values, base excess and heart rate were statistically significant (p<0.01) in control group and there was no significant difference (p>0.05) in experimental group. The values of pH, chest expansion and respiratory rate were highly significant (p<0.01) in both control as well as experimental group. Conclusion: ACBT was more effective to decrease post CABG complication as compared to conventional chest physical therapy. Some parameters like bicarbonate values, base excess and heart rate did not show improvement with ACBT. (author)

  6. Craniofacial tissue oxygen saturation is associated with blood pH using an examiner's finger-mounted tissue oximetry in mice

    Science.gov (United States)

    Uchida, Toshiyuki; Kanayama, Naohiro; Kawai, Kenta; Niwayama, Masatsugu

    2016-04-01

    Although fetal scalp blood sampling is an examination to assess fetal acidosis during the intrapartum period, it has not been widely used by obstetricians because of its invasiveness. We have developed a small, portable oximetry with a sensor attached to the examiner's finger. Our previous report using this oximetry concluded that fetal head tissue oxygen saturation (StO2) correlated with umbilical cord artery blood pH. We investigated whether the association between StO2 and blood pH in mice could be validated using this oximetry. Eleven the Institute for Cancer Research (ICR) mice were measured using a near-infrared spectroscopy probe at the craniofacial site in a closed polyethylene bag while changing the oxygen concentration. A total of nine blood samples were collected and analyzed for pH. The StO2 and tissue blood pH showed a strong positive correlation (r=0.90 and P=0.0009). The StO2 and total hemoglobin index also showed a positive correlation (r=0.84 and P=0.0049). Thus, the results of the present study support those of our previous report on clinical cases and allow examiners to easily check the status of fetal acidosis. Fetal management using this oximetry might gain popularity with obstetricians in the near future.

  7. Optimal oxygen saturation in premature infants

    OpenAIRE

    Meayoung Chang

    2011-01-01

    There is a delicate balance between too little and too much supplemental oxygen exposure in premature infants. Since underuse and overuse of supplemental oxygen can harm premature infants, oxygen saturation levels must be monitored and kept at less than 95% to prevent reactive oxygen species-related diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia. At the same time, desaturation below 80 to 85% must be avoided to prevent adverse consequences, such as cerebra...

  8. Oxygen Saturation Targeting and Bronchopulmonary Dysplasia.

    Science.gov (United States)

    Darlow, Brian A; Morley, Colin J

    2015-12-01

    Oxygen saturation targeting is widely used in neonatal intensive care, but the optimal target range in very preterm infants has been uncertain and is the subject of recent debate and research. This review briefly discusses the technology of oxygen monitoring and the role of oxygen toxicity in preterm infants. The background to the recent trials of oxygen saturation targeting in acute and continuing care of very preterm infants is reviewed, and the findings and implications of the recent trials, particularly with respect to bronchopulmonary dysplasia, are discussed. PMID:26593080

  9. Optimal oxygen saturation in premature infants

    Directory of Open Access Journals (Sweden)

    Meayoung Chang

    2011-09-01

    Full Text Available There is a delicate balance between too little and too much supplemental oxygen exposure in premature infants. Since underuse and overuse of supplemental oxygen can harm premature infants, oxygen saturation levels must be monitored and kept at less than 95% to prevent reactive oxygen species-related diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia. At the same time, desaturation below 80 to 85% must be avoided to prevent adverse consequences, such as cerebral palsy. It is still unclear what range of oxygen saturation is appropriate for premature infants; however, until the results of further studies are available, a reasonable target for pulse oxygen saturation (SpO2 is 90 to 93% with an intermittent review of the correlation between SpO2 and the partial pressure of arterial oxygen tension (PaO2. Because optimal oxygenation depends on individuals at the bedside making ongoing adjustments, each unit must define an optimal target range and set alarm limits according to their own equipment or conditions. All staff must be aware of these values and adjust the concentration of supplemental oxygen frequently.

  10. Relating oxygen partial pressure, saturation and content: the haemoglobin–oxygen dissociation curve

    Directory of Open Access Journals (Sweden)

    Julie-Ann Collins

    2015-09-01

    The delivery of oxygen by arterial blood to the tissues of the body has a number of critical determinants including blood oxygen concentration (content, saturation (SO2 and partial pressure, haemoglobin concentration and cardiac output, including its distribution. The haemoglobin–oxygen dissociation curve, a graphical representation of the relationship between oxygen satur­ation and oxygen partial pressure helps us to understand some of the principles underpinning this process. Historically this curve was derived from very limited data based on blood samples from small numbers of healthy subjects which were manipulated in vitro and ultimately determined by equations such as those described by Severinghaus in 1979. In a study of 3524 clinical specimens, we found that this equation estimated the SO2 in blood from patients with normal pH and SO2 >70% with remarkable accuracy and, to our knowledge, this is the first large-scale validation of this equation using clinical samples. Oxygen saturation by pulse oximetry (SpO2 is nowadays the standard clinical method for assessing arterial oxygen saturation, providing a convenient, pain-free means of continuously assessing oxygenation, provided the interpreting clinician is aware of important limitations. The use of pulse oximetry reduces the need for arterial blood gas analysis (SaO2 as many patients who are not at risk of hypercapnic respiratory failure or metabolic acidosis and have acceptable SpO2 do not necessarily require blood gas analysis. While arterial sampling remains the gold-standard method of assessing ventilation and oxygenation, in those patients in whom blood gas analysis is indicated, arterialised capillary samples also have a valuable role in patient care. The clinical role of venous blood gases however remains less well defined.

  11. Nasal pulse oximetry overestimates oxygen saturation

    DEFF Research Database (Denmark)

    Rosenberg, J; Pedersen, M H

    1990-01-01

    Ten surgical patients were monitored with nasal and finger pulse oximetry (Nellcor N-200) for five study periods with alternating mouth and nasal breathing and switching of cables and sensors. Nasal pulse oximetry was found to overestimate arterial oxygen saturation by 4.7 (SD 1.4%) (bias and...

  12. Comparison of pre-workout nitric oxide stimulating dietary supplements on skeletal muscle oxygen saturation, blood nitrate/nitrite, lipid peroxidation, and upper body exercise performance in resistance trained men

    OpenAIRE

    Canale Robert E; McCarthy Cameron G; Trepanowski John F; Farney Tyler M; Bloomer Richard J; Schilling Brian K

    2010-01-01

    Abstract Background We compared Glycine Propionyl-L-Carnitine (GlycoCarn®) and three different pre-workout nutritional supplements on measures of skeletal muscle oxygen saturation (StO2), blood nitrate/nitrite (NOx), lactate (HLa), malondialdehyde (MDA), and exercise performance in men. Methods Using a randomized, double-blind, cross-over design, 19 resistance trained men performed tests of muscular power (bench press throws) and endurance (10 sets of bench press to muscular failure). A place...

  13. Single-cell measurement of red blood cell oxygen affinity

    CERN Document Server

    Caprio, Di; Higgins, John M; Schonbrun, Ethan

    2015-01-01

    Oxygen is transported throughout the body by hemoglobin in red blood cells. While the oxygen affinity of blood is well understood and is routinely assessed in patients by pulse oximetry, variability at the single-cell level has not been previously measured. In contrast, single-cell measurements of red blood cell volume and hemoglobin concentration are taken millions of times per day by clinical hematology analyzers and are important factors in determining the health of the hematologic system. To better understand the variability and determinants of oxygen affinity on a cellular level, we have developed a system that quantifies the oxygen saturation, cell volume and hemoglobin concentration for individual red blood cells in high-throughput. We find that the variability in single-cell saturation peaks at an oxygen partial pressure of 2.5%, which corresponds to the maximum slope of the oxygen-hemoglobin dissociation curve. In addition, single-cell oxygen affinity is positively correlated with hemoglobin concentr...

  14. The relation between oxygen saturation level and retionopathy of prematurity

    Directory of Open Access Journals (Sweden)

    Mohammad Gharavi Fard

    2016-03-01

    Full Text Available Introduction: Oxygen therapy used for preterm infant disease might be associated with oxygen toxicity or oxidative stress. The exact oxygen concentration to control and maintain the arterial oxygen saturation balance is not certainly clear. We aimed to compare the efficacy of higher or lower oxygen saturations on the development of severe retinopathy of prematurity which is a major cause of blindness in preterm neonates. Methods: PubMed was searched for obtaining the relevant articles. A total of seven articles were included after studying the titles, abstracts, and the full text of retrieved articles at initial search. Inclusion criteria were all the English language human clinical randomized controlled trials with no time limitation, which studied the efficacy of low versus high oxygen saturation measured by pulse oximetry in preterm infants.Result: It can be suggested that lower limits of oxygen saturations have higher efficacy at postmesetural age of ≤28 weeks in preterm neonates. This relation has been demonstrated in five large clinical trials including three Boost trials, COT, and Support.Discussion: Applying higher concentrations of oxygen supplementations at mesentural age ≥32 weeks reduced the development of retinopathy of prematurity. Lower concentrations of oxygen saturation decreased the incidence and the development of retinopathy of prematurity in preterm neonates while applied soon after the birth.Conclusions: Targeting levels of oxygen saturation in the low or high range should be performed cautiously with attention to the postmesentural age in preterm infants at the time of starting the procedures.

  15. Effect of low-level laser therapy on blood flow and oxygen- hemoglobin saturation of the foot skin in healthy subjects: a pilot study

    OpenAIRE

    Heu, Franziska; Forster, Clemens; Namer, Barbara; Dragu, Adrian; Lang, Werner

    2013-01-01

    Background and aims: This study on healthy test subjects intends to show whether one-off Low-Level Laser Therapy (LLLT) has an instant effect on the perfusion or the oxygenation of the skin tissue. These possible instant effects may have an influence on the accelerated wound healing which is often observed after application of LLLT, in addition to the usual postulated effects of LLLT which occur with a time delay normally.

  16. Comparison the Effects of Shallow and Deep Endotracheal Tube Suctioning on Respiratory Rate, Arterial Blood Oxygen Saturation and Number of Suctioning in Patients Hospitalized in the Intensive Care Unit: A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Mohammad Abbasinia

    2014-09-01

    Full Text Available Introduction: Endotracheal tube suctioning is essential for improve oxygenation in the patients undergoing mechanical ventilation. There are two types of shallow and deep endotracheal tube suctioning. This study aimed to evaluate the effect of shallow and deep suctioning methods on respiratory rate (RR, arterial blood oxygen saturation (SpO2 and number of suctioning in patients hospitalized in the intensive care units of Al-Zahra Hospital, Isfahan, Iran. Methods: In this randomized controlled trial, 74 patients who hospitalized in the intensive care units of Isfahan Al-Zahra Hospital were randomly allocated to the shallow and deep suctioning groups. RR and SpO2 were measured immediately before, immediately after, 1 and 3 minute after each suctioning. Number of suctioning was also noted in each groups. Data were analyzed using repeated measures analysis of variance (RMANOVA, chi-square and independent t-tests. Results: RR was significantly increased and SpO2 was significantly decreased after each suctioning in the both groups. However, these changes were not significant between the two groups. The numbers of suctioning was significantly higher in the shallow suctioning group than in the deep suctioning group. Conclusion: Shallow and deep suctioning had a similar effect on RR and SpO2. However, shallow suctioning caused further manipulation of patient’s trachea than deep suctioning method. Therefore, it seems that deep endotracheal tube suctioning method can be used to clean the airway with lesser manipulation of the trachea.

  17. Maintaining Optimal Oxygen Saturation in Premature Infants

    OpenAIRE

    Lau, Yoke Yen; Tay, Yih Yann; Shah, Varsha Atul; Chang, Pisun; Loh, Khuan Tai

    2011-01-01

    Introduction: Advances in technology have resulted in increasing survival rates for premature infants. Oxygen therapy is commonly used in neonatal units as part of respiratory support. The number of premature infants in our institution surviving with severe (stage ≥3) retinopathy of prematurity (ROP) prompted a review of oxygen therapy as a contributing factor. Prolonged exposure to high concentrations of oxygen may cause irreversible damage to the eyes of very-low-birth-weight preterm infant...

  18. Effect of interscalene anaesthesia on cerebral oxygen saturation.

    Science.gov (United States)

    Soeding, P F; Currigan, D A; Mamo, Y; Hoy, G

    2016-05-01

    Interscalene blockade (ISB) is commonly associated with Horner's syndrome, indicating spread of injectate to the cervical sympathetic chain. Cervical sympathetic nerve activity (SNA) is believed to influence cerebral autoregulation, and a decrease in sympathetic tone may alter cerebral blood flow (CBF). This study investigated whether ISB influenced CBF in patients undergoing shoulder surgery. Patients (n=30) scheduled for elective shoulder arthroscopy were recruited. Cerebral oxygen saturation (ScO2) of the left and right frontal cortices was continuously measured during ISB administration, sedation and anaesthetic induction. Baseline ScO2 was similar in blocked and unblocked sides (74 ± 5% and 73 ± 5% respectively, P=0.70). ScO2 decreased with sedation (-3 ± 3% and -4 ± 3%, P=0.93), and increased with pre-oxygenation and general anaesthesia (P blocked and unblocked sides (P=0.18), or any difference between right- or left-sided ISB. ISB is not associated with an increase in CBF as indicated by ScO2, despite the presence of Horner's syndrome. PMID:27246935

  19. Oxygen saturation limits and evidence supporting the targets.

    Science.gov (United States)

    Newnam, Katherine M

    2014-12-01

    Supplemental oxygen use in the preterm infant is required for survival. Evidence supports a narrow therapeutic window between the helpful and harmful effects of supplemental oxygen in this vulnerable population. The clinical question was-what are the recommended oxygen saturation targets for the preterm infant and the preterm infant corrected to term? Multiple databases were searched for published research in English from 2008 to 2014 using key search terms. A total of 18 articles met inclusion criteria. Early neonatal research linked high levels of supplemental oxygen with retinopathy of prematurity and blindness. Years later, correlations between high arterial oxygen levels and oxidative stress leading to pulmonary and/or neurologic insults were established. Three large multicentered, international studies have recently been published (BOOST II, COT, and SUPPORT), which support oxygen saturation target ranges of 87% to 94% until vascular maturation of the retina is achieved. Two of the 3 studies reported a significant correlation between low saturation limits (85%-89%) and death in the extremely preterm population. Identified best care strategies to prevent states of hypoxia and/or hyperoxia include establishing clear target saturation limits according to recommendations, which are supported by the multidisciplinary team, adequate nurse to patient ratio, improve knowledge deficits, improve bedside compliance, and finally visual cues to remind caregivers of target saturation ranges. PMID:25422926

  20. Comparison of pre-workout nitric oxide stimulating dietary supplements on skeletal muscle oxygen saturation, blood nitrate/nitrite, lipid peroxidation, and upper body exercise performance in resistance trained men

    Directory of Open Access Journals (Sweden)

    Canale Robert E

    2010-05-01

    Full Text Available Abstract Background We compared Glycine Propionyl-L-Carnitine (GlycoCarn® and three different pre-workout nutritional supplements on measures of skeletal muscle oxygen saturation (StO2, blood nitrate/nitrite (NOx, lactate (HLa, malondialdehyde (MDA, and exercise performance in men. Methods Using a randomized, double-blind, cross-over design, 19 resistance trained men performed tests of muscular power (bench press throws and endurance (10 sets of bench press to muscular failure. A placebo, GlycoCarn®, or one of three dietary supplements (SUPP1, SUPP2, SUPP3 was consumed prior to exercise, with one week separating conditions. Blood was collected before receiving the condition and immediately after exercise. StO2 was measured during the endurance test using Near Infrared Spectroscopy. Heart rate (HR and rating of perceived exertion (RPE were determined at the end of each set. Results A condition effect was noted for StO2 at the start of exercise (p = 0.02, with GlycoCarn® higher than SUPP2. A condition effect was also noted for StO2 at the end of exercise (p = 0.003, with SUPP1 lower than all other conditions. No statistically significant interaction, condition, or time effects were noted for NOx or MDA (p > 0.05; however, MDA decreased 13.7% with GlycoCarn® and increased in all other conditions. Only a time effect was noted for HLa (p 0.05; however, GlycoCarn® resulted in a statistically insignificant greater total volume load compared to the placebo (3.3%, SUPP1 (4.2%, SUPP2 (2.5%, and SUPP3 (4.6%. Conclusion None of the products tested resulted in favorable changes in our chosen outcome measures, with the exception of GlycoCarn® in terms of higher StO2 at the start of exercise. GlycoCarn® resulted in a 13.7% decrease in MDA from pre- to post-exercise and yielded a non-significant but greater total volume load compared to all other conditions. These data indicate that 1 a single ingredient (GlycoCarn® can provide similar practical benefit

  1. Seven-day mortality can be predicted in medical patients by blood pressure, age, respiratory rate, loss of independence, and peripheral oxygen saturation (the PARIS score: a prospective cohort study with external validation.

    Directory of Open Access Journals (Sweden)

    Mikkel Brabrand

    Full Text Available Most existing risk stratification systems predicting mortality in emergency departments or admission units are complex in clinical use or have not been validated to a level where use is considered appropriate. We aimed to develop and validate a simple system that predicts seven-day mortality of acutely admitted medical patients using routinely collected variables obtained within the first minutes after arrival.This observational prospective cohort study used three independent cohorts at the medical admission units at a regional teaching hospital and a tertiary university hospital and included all adult (≥ 15 years patients. Multivariable logistic regression analysis was used to identify the clinical variables that best predicted the endpoint. From this, we developed a simplified model that can be calculated without specialized tools or loss of predictive ability. The outcome was defined as seven-day all-cause mortality. 76 patients (2.5% met the endpoint in the development cohort, 57 (2.0% in the first validation cohort, and 111 (4.3% in the second. Systolic blood Pressure, Age, Respiratory rate, loss of Independence, and peripheral oxygen Saturation were associated with the endpoint (full model. Based on this, we developed a simple score (range 0-5, ie, the PARIS score, by dichotomizing the variables. The ability to identify patients at increased risk (discriminatory power and calibration was excellent for all three cohorts using both models. For patients with a PARIS score ≥ 3, sensitivity was 62.5-74.0%, specificity 85.9-91.1%, positive predictive value 11.2-17.5%, and negative predictive value 98.3-99.3%. Patients with a score ≤ 1 had a low mortality (≤ 1%; with 2, intermediate mortality (2-5%; and ≥ 3, high mortality (≥ 10%.Seven-day mortality can be predicted upon admission with high sensitivity and specificity and excellent negative predictive values.

  2. [Measurement of multi-wavelength pulse oxygen saturation based on dynamic spectroscopy].

    Science.gov (United States)

    Wang, Xiao-Fei; Zhao, Wen-Jun

    2014-05-01

    The present paper puts forward multi-wavelength pulse oxygen saturation measurement based on dynamic spectroscopy to do the non-invasive determination of oxygen saturation. Compared to conventional ways, the new method makes full use of more wavelengths light and improves the measurement accuracy. During the experiment, the in-vivo measurements were carried out on 60 patients and their spectroscopic data were collected by the high sensitivity type fiber optic spectrometer. Singletrial estimation method was used to extract the dynamic spectroscopy at the wavelengths of 606. 44 approximately 987. 55 nm. Oxygen saturation obtained from arterial blood gas analysis is regarded as the true value. Synergy interval partial least square (siPLS) was used to establish the calibration model of subjects' oxygen saturation values against dynamic spectroscopy data. The relative error of prediction is +/-0. 017 6, but the relative error of the subjects in the same set measured by the patient monitor which was two-wavelength measure system is +/-0. 116 4. Measurement results show that the use of the high sensitivity type fiber optic spectrometer to collect multi-wavelength spectroscopic data and dynamic spectroscopy method to process data can do better in improving the accuracy of the oxygen saturation measurement. PMID:25095431

  3. Intensity of an oxygen saturation image improved using scanning NIR-LED light irradiation

    Science.gov (United States)

    Tsai, Hsin-Yi; Yang, Ching-Ching; Hung, Min-Wei; Huang, Kuo-Cheng

    2014-09-01

    A near-infrared (940 nm) image of skin tissue can be substantially enhanced using optical scanning technology (OST) that can reduce the scattering effect and remove the wrinkles or fine hair in the image. Using OST to create the skin tissue image ensured that the contour of blood vessels became more clear than that obtained from the divergent light source. In addition, the oxygen saturation of the blood vessels and tissues obtained using OST were approximately 98.65 and 93.17%, respectively, exhibiting an increase of more than 20% compared with that obtained using divergent light, and approached the value when measured using commercial pulse oximetry. Because the proposed method has a deep light penetration depth and high image intensity and resolution for oxygen saturation analysis, it is highly appropriate to be applied to future studies on diabetes and cardiovascular diseases.

  4. A reflectance model for non-contact mapping of venous oxygen saturation using a CCD camera

    Science.gov (United States)

    Li, Jun; Dunmire, Barbrina; Beach, Kirk W.; Leotta, Daniel F.

    2013-11-01

    A method of non-contact mapping of venous oxygen saturation (SvO2) is presented. A CCD camera is used to image skin tissue illuminated alternately by a red (660 nm) and an infrared (800 nm) LED light source. Low cuff pressures of 30-40 mmHg are applied to induce a venous blood volume change with negligible change in the arterial blood volume. A hybrid model combining the Beer-Lambert law and the light diffusion model is developed and used to convert the change in the light intensity to the change in skin tissue absorption coefficient. A simulation study incorporating the full light diffusion model is used to verify the hybrid model and to correct a calculation bias. SvO2 in the fingers, palm, and forearm for five volunteers are presented and compared with results in the published literature. Two-dimensional maps of venous oxygen saturation are given for the three anatomical regions.

  5. Recombinant human growth hormone and insulin-like growth factor-1 do not affect mitochondrial derived highly reactive oxygen species production in peripheral blood mononuclear cells under conditions of substrate saturation in-vitro

    OpenAIRE

    Keane, James; Tajouri, Lotti; Gray, Bon

    2016-01-01

    Background The purpose of this study was to investigate the mitochondrial effects exerted by physiological and supra-physiological concentrations of recombinant human growth hormone (rhGH) and recombinant insulin-like growth factor-1 (rIGF-1) under conditions of substrate saturation in peripheral blood mononuclear cells (PBMCs). Methods PBMCs from healthy male subjects were treated with either rhGH, at concentrations of 0.5, 5 and 50 μg/L, or rIGF-1 at concentrations of 100, 300 and 500 μg/L ...

  6. Agreement of noninvasive cerebral oxygenation with mixed venous oxygen saturation in patients undergoing ECMO-therapy

    OpenAIRE

    H. Paarmann; J. Schön; W. Schmidt; Heinze, H; K.-U. Berger; B. Sedemund-Adib; Bechtel, M; Heringlake, M; H. V. Groesdonk

    2011-01-01

    Purpose: Approximately 1% of patients require temporary circulatory support due to cardiogenic shock following cardiac surgery. These patients are at risk of a mismatch between oxygen delivery and demand and carry a substantial mortality and morbidity risk. Mixed venous oxygen saturation (SvO2) is the still the “gold standard” for the determination of the ratio between systemic oxygen delivery and consumption (DO2/VO2 ratio) in cardiac surgery patients. A noninvasive technique is thought to b...

  7. Study of retinal vessel oxygen saturation in ischemic and non-ischemic branch retinal vein occlusion

    Science.gov (United States)

    Lin, Lei-Lei; Dong, Yan-Min; Zong, Yao; Zheng, Qi-Shan; Fu, Yue; Yuan, Yong-Guang; Huang, Xia; Qian, Garrett; Gao, Qian-Ying

    2016-01-01

    AIM To explore how oxygen saturation in retinal blood vessels is altered in ischemic and non-ischemic branch retinal vein occlusion (BRVO). METHODS Fifty BRVO eyes were divided into ischemic (n=26) and non-ischemic (n=24) groups, based on fundus fluorescein angiography. Healthy individuals (n=52 and n=48, respectively) were also recruited as controls for the two groups. The mean oxygen saturations of the occluded vessels and central vessels were measured by oximetry in the BRVO and control groups. RESULTS In the ischemic BRVO group, the occluded arterioles oxygen saturation (SaO2-A, 106.0%±14.3%), instead of the occluded venule oxygen saturation (SaO2-V, 60.8%±9.4%), showed increases when compared with those in the same quadrant vessels (SaO2-A, 86.1%±16.5%) in the contralateral eyes (P<0.05). The oxygen saturations of the central vessels showed similar trends with those of the occluded vessels. In the non-ischemic BRVO group, the occluded and central SaO2-V and SaO2-A showed no significant changes. In both the ischemic and non-ischemic BRVOs, the central SaO2-A was significantly increased when compared to healthy individuals. CONCLUSION Obvious changes in the occluded and central SaO2-A were found in the ischemic BRVO group, indicating that disorders of oxygen metabolism in the arterioles may participate in the pathogenesis of ischemic BRVO. PMID:26949618

  8. End expiratory oxygen concentrations to predict central venous oxygen saturation: an observational pilot study

    Directory of Open Access Journals (Sweden)

    Steuerwald Michael

    2006-09-01

    Full Text Available Abstract Background A non-invasive surrogate measurement for central venous oxygen saturation (ScVO2 would be useful in the ED for assessing therapeutic interventions in critically ill patients. We hypothesized that either linear or nonlinear mathematical manipulation of the partial pressure of oxygen in breath at end expiration (EtO2 would accurately predict ScVO2. Methods Prospective observational study of a convenience sample of hemodialysis patients age > 17 years with existing upper extremity central venous catheters were enrolled. Using a portable respiratory device, we collected both tidal breathing and end expiratory oxygen and carbon dioxide concentrations, volume and flow on each patient. Simultaneous ScVO2 measurements were obtained via blood samples collected from the hemodialysis catheter. Two models were used to predict ScVO2: 1 Best-fit multivariate linear regression equation incorporating all respiratory variables; 2 MathCAD to model the decay curve of EtO2 versus expiratory volume using the least squares method to estimate the pO2 that would occur at Results From 21 patients, the correlation between EtO2 and measured ScVO2 yielded R2 = 0.11. The best fit multivariate equation included EtCO2 and EtO2 and when solved for ScVO2, the equation yielded a mean absolute difference from the measured ScVO2 of 8 ± 6% (range -18 to +17%. The predicted ScVO2 value was within 10% of the actual value for 57% of the patients. Modeling of the EtO2 curve did not accurately predict ScVO2 at any lung volume. Conclusion We found no significant correlation between EtO2 and ScVO2. A linear equation incorporating EtCO2 and EtO2 had at best modest predictive accuracy for ScVO2.

  9. Analysis of factors which affect the relationship between inspired oxygen partial pressure and arterial oxygen saturation.

    Science.gov (United States)

    Roe, P G; Jones, J G

    1993-10-01

    The adoption of pulse oximetry in anaesthesia and intensive care has resulted in oxyhaemoglobin saturation (SaO2) becoming an important and widely used clinical descriptor of gas exchange, although its full potential has not been realized. We have explored the effect of impaired gas exchange on the relationship between PIO2 and SaO2. A curve of oxygen content vs PIO2 for an ideal lung was constructed using the oxygen dissociation curve and allowing for the effect of dissolved oxygen in plasma. A plot of PIO2 vs SaO2 was derived from this content curve. The effect of impaired gas exchange (shunt and V/Q effects) on this relationship was then modelled using for shunt the equation Qs/Qt = (Cc' O2-CaO2)/(Cc' O2-CvO2) and for V/Q, a graphical method using the equation V/Q = k(Cc' O2-CvO2)/ (PIO2-PAO2) and the oxygen content curve to model the effect of a spread of V/Q ratios. A total of nine compartments were used to model the scatter of V/Q, and the size of these compartments were determined by their relative blood supply. Plots of PIO2 vs SaO2 were derived for different values of shunt and V/Q. The PIO2 vs SaO2 curve reflected the shape of the oxygen dissociation curve but lay to the right by PIO2-PAO2. Shunt caused a depression of the plateau of this curve with relatively little lateral movement, whereas a low mean V/Q ratio caused a marked rightwards lateral displacement. Increased IogSD Q caused a flattening of the relationship. The combined effect of shunt and a spread of V/Q ratios caused both lateral and vertical displacements. Thus a series of simple measurements of PIO2 and SaO2 gave information about both shunt and V/Q abnormality. PMID:8260294

  10. Angiogram, fundus, and oxygen saturation optic nerve head image fusion

    Science.gov (United States)

    Cao, Hua; Khoobehi, Bahram

    2009-02-01

    A novel multi-modality optic nerve head image fusion approach has been successfully designed. The new approach has been applied on three ophthalmologic modalities: angiogram, fundus, and oxygen saturation retinal optic nerve head images. It has achieved an excellent result by giving the visualization of fundus or oxygen saturation images with a complete angiogram overlay. During this study, two contributions have been made in terms of novelty, efficiency, and accuracy. The first contribution is the automated control point detection algorithm for multi-sensor images. The new method employs retina vasculature and bifurcation features by identifying the initial good-guess of control points using the Adaptive Exploratory Algorithm. The second contribution is the heuristic optimization fusion algorithm. In order to maximize the objective function (Mutual-Pixel-Count), the iteration algorithm adjusts the initial guess of the control points at the sub-pixel level. A refinement of the parameter set is obtained at the end of each loop, and finally an optimal fused image is generated at the end of the iteration. It is the first time that Mutual-Pixel-Count concept has been introduced into biomedical image fusion area. By locking the images in one place, the fused image allows ophthalmologists to match the same eye over time and get a sense of disease progress and pinpoint surgical tools. The new algorithm can be easily expanded to human or animals' 3D eye, brain, or body image registration and fusion.

  11. End expiratory oxygen concentrations to predict central venous oxygen saturation: an observational pilot study

    OpenAIRE

    Steuerwald Michael; Kuehne Karl; Jones Alan E; Kline Jeffrey A

    2006-01-01

    Abstract Background A non-invasive surrogate measurement for central venous oxygen saturation (ScVO2) would be useful in the ED for assessing therapeutic interventions in critically ill patients. We hypothesized that either linear or nonlinear mathematical manipulation of the partial pressure of oxygen in breath at end expiration (EtO2) would accurately predict ScVO2. Methods Prospective observational study of a convenience sample of hemodialysis patients age > 17 years with existing upper ex...

  12. Developmental Effects Determine Submaximal Arterial Oxygen Saturation in Peruvian Quechua.

    Science.gov (United States)

    Kiyamu, Melisa; León-Velarde, Fabiola; Rivera-Chira, María; Elías, Gianpietro; Brutsaert, Tom D

    2015-06-01

    Kiyamu, Melisa, Fabiola León-Velarde, María Rivera-Chira, Gianpietro Elías, and Tom D. Brutsaert. Developmental effects determine submaximal arterial oxygen saturation in Peruvian Quechua. High Alt Med Biol 16, 138-146, 2015.--Andean high altitude natives show higher arterial oxygen saturation (Sao(2)) during exercise in hypoxia, compared to acclimatized sojourners. In order to evaluate the effects of life-long exposure to high altitude on Sao(2), we studied two groups of well-matched, self-identified Peruvian Quechua natives who differed in their developmental exposure to hypoxia before and after a 2-month training period. Male and female volunteers (18-35 years) were recruited in Lima, Peru (150 m). The two groups were: a) Individuals who were born and raised at sea-level (BSL, n=34) and b) Individuals who were born and raised at high altitude (BHA, n=32), but who migrated to sea-level as adults (>16 years old). Exercise testing was conducted using a submaximal exercise protocol in normobaric hypoxia in Lima (BP=750 mmHg, Fio(2)=0.12), in order to measure Sao(2) (%), ventilation (VE L/min) and oxygen consumption (Vo(2), L/min). Repeated-measures ANOVA, controlling for VE/VO(2) (L/min) and sex during the submaximal protocol showed that BHA maintained higher Sao(2) (%) compared to BSL at all workloads before (p=0.005) and after training (p=0.017). As expected, both groups showed a decrease in Sao(2) (%) (p<0.001), as workload increased. Resting Sao(2) levels were not found to be different between groups. The results suggest that developmental exposure to altitude contributes to the maintenance of higher Sao(2) levels during submaximal exercise at hypoxia. PMID:25977978

  13. Validation of NIRS in measuring tissue hemoglobin concentration and oxygen saturation on ex vivo and isolated limb models

    Science.gov (United States)

    Xu, Xiaorong; Zhu, Wen; Padival, Vikram; Xia, Mengna; Cheng, Xuefeng; Bush, Robin; Christenson, Linda; Chan, Tim; Doherty, Tim; Iatridis, Angelo

    2003-07-01

    Photonify"s tissue spectrometer uses Near-Infrared Spectroscopy for real-time, noninvasive measurement of hemoglobin concentration and oxygen saturation [SO2] of biological tissues. The technology was validated by a series of ex vivo and animal studies. In the ex vivo experiment, a close loop blood circulation system was built, precisely controlling the oxygen saturation and the hemoglobin concentration of a liquid phantom. Photonify"s tissue spectrometer was placed on the surface of the liquid phantom for real time measurement and compared with a gas analyzer, considered the gold standard to measure oxygen saturation and hemoglobin concentration. In the animal experiment, the right hind limb of each dog accepted onto the study was surgically removed. The limb was kept viable by connecting the femoral vein and artery to a blood-primed extracorporeal circuit. Different concentrations of hemoglobin were obtained by adding designated amount of saline solution into the perfusion circuit. Photonify"s tissue spectrometers measured oxygen saturation and hemoglobin concentration at various locations on the limb and compared with gas analyzer results. The test results demonstrated that Photonify"s tissue spectrometers were able to detect the relative changes in tissue oxygen saturation and hemoglobin concentration with a high linear correlation compared to the gas analyzer

  14. Effect of oxygen on tachycardia and arterial oxygen saturation during colonoscopy

    DEFF Research Database (Denmark)

    Holm, C; Christensen, M; Schulze, S;

    1999-01-01

    through nasal prongs (2 L/min), and 20 patients breathed room air during colonoscopy. All patients were given conscious sedation and were monitored with a pulse oximeter during colonoscopy. MAIN OUTCOME MEASURES: Tachycardia (pulse rate>100 min(-1)) and arterial oxygen desaturation (SpO2...OBJECTIVE: To evaluate the effect of supplementary oxygen on heart rate and arterial oxygen saturation during colonoscopy. DESIGN: Controlled study. SETTING: Two university hospitals, Denmark. SUBJECTS: 40 patients having colonoscopy. INTERVENTIONS: 20 patients were given supplementary oxygen...... colonoscopy. RESULTS: There were no differences in the incidence of tachycardia or mean heart rate during endoscopy between the two groups, and no patient developed symptomatic cardiac arrhythmias or hypotensive episodes. 10 patients in the room air compared with none in the oxygen treatment group (p = 0...

  15. Non-invasive measurement and validation of tissue oxygen saturation covered with overlying tissues

    Institute of Scientific and Technical Information of China (English)

    Yichao Teng; Haishu Ding; Lan Huang; Yue Li; Quanzhong Shan; Datian Ye; Haiyan Ding; Jenchung Chien; Betau Hwang

    2008-01-01

    In this paper,the biological tissue oxygen saturation(rS02)is obtained non-invasively and in real time based on near infrared spec-troscopy(NIRS)using two emitting wavelengths and two detectors,where the tissue is covered with overlying tissues.Our group devel-oped an NIRS oximeter based on the above principle independently,and validated it using liquid tissue model calibrations and animal experiments.The results indicate that(1)in the normal range of tissue oxygen saturation(40-70%),the rS02 measured by NIRS is accu-rate enough and little influenced by the background absorptions(such as the absorption of water)and overlying tissues(such as fat);(2)during cerebral hypoxia and recovery of three piglets,there is excellent correlation(p<0.001)between cerebral rS02 and jugular venous oxygen saturation(Sj02),meaning that the rS02 can be indicated by the Sj02 to a large extent;during the death of the three piglets induced by heart beat stopping,cerebral rS02 decreases continuously to significantly low levels(<25%)because cerebral blood supply does not exist any more.All the above results are of explicit physiological importance.

  16. Reference values of capillary blood saturation in neonates and its difference from pulse oximetry

    Directory of Open Access Journals (Sweden)

    Ješić Miloš M.

    2010-01-01

    Full Text Available Introduction Haemoglobin saturation is an obligatory oxygen parameter in the assessment of neonatal oxygenation. Although, pulse oximetry is currently one of the major methods in the determination of haemoglobin saturation, capillary blood saturation is still present in the diagnostic process. As well known, haemoglobin saturation value of capillary blood is insufficiently accurate, but not as much as the difference in relation to the values determined by pulse oximetry. Until now published studies have reported that capillary samples are obtained according to a protocol by the principle of free blood outflow, which is practically almost unachievable in the neonate. Objective Determination of the reference values of oxygen saturation (ScO2 and partial pressure (pcO2 of capillary blood by squeezing of the foot. The determination of difference between ScO2 and pulse oximetry (SpO2. Methods In 134 term newborns, we determined SpO2 . Subsequently, we measured the values of ScO2 and pcO2 from the same extremity. While withdrawing a capillary sample, we exerted multiple squeezing of the foot. The mean value of ScO2, pcO2, SpO2 and the difference between ScO2 and SpO2 were determined. Results Mean ScO2 value was 80.5}8.5%, pcO2 was 48.2}11.4 mm Hg and SpO2 was 98}1.9%. The difference between ScO2 and SpO2 values was 17.5}8.6% (t=23.568; p=0.000. Conclusion There is a statistically highly significant difference between the values of ScO2 and SpO2. Having the knowledge of this difference can increase the accuracy of clinical evaluation and further diagnostics. Comparison in up-to-now conducted studies suggests that the squeezing of the foot for obtaining a capillary sample in relation to free blood outflow does not bear any significant influence on the resultant values of haemoglobin saturation. .

  17. Local changes in arterial oxygen saturation induced by visible and near-infrared light radiation.

    Science.gov (United States)

    Yesman, S S; Mamilov, S O; Veligotsky, D V; Gisbrecht, A I

    2016-01-01

    In this study, we investigate the efficiency of laser radiation on oxyhemoglobin (HbO2) rate in blood vessels and its wavelength dependence. The results of in vivo experimental measurements of the laser-induced photodissociation of HbO2 in cutaneous blood vessels in the visible and near-infrared (IR) spectral range are presented. Arterial oxygen saturation (SpO2) was measured by a method of fingertip pulse oximetry, which is based on the measurement of the modulated pulse wave of the blood. The light irradiating the finger was provided by corresponding light-emitting diodes (LED) at 15 wavelengths in the 400-940 nm spectrum range. Statistical results with a value of p phototherapy of pathologies, where the elimination of local tissue hypoxia is critical. PMID:26637304

  18. Micro-regional mapping of HbO2 saturations and blood flow following nicotinamide administration

    International Nuclear Information System (INIS)

    Although nicotinamide administration has increased the radiosensitivity of experimental tumors, there is a scarcity of data detailing the underlying physiological mechanisms. The current study presents a method for quantifying both microregional distributions of intravascular HbO2 saturations and the presence or absence of blood flow in adjacent frozen tumor sections. Two murine tumor cell lines, KHT and SCCVII, were implanted and quick-frozen without the use of anesthetics. Nicotinamide was administered IP 1 h prior to freezing, and a fluorescent dye that preferentially stains cells adjacent to blood vessels was injected IV 1 min prior to freezing. To visualize the presence or absence of blood flow, six micron sections were first cut using a cryostat. The remaining frozen tumor block was then analyzed cryospectrophotometrically to determine intravascular HbO2 levels. While KHT HbO2 levels increased somewhat predictably following nicotinamide, the response in SCCVII tumors varied with distance from the tumor surface. Near the periphery, SCCVII HbO2 levels increased, but nearer the tumor center, HbO2 levels actually decreased. Perfused blood vessels were uniformly distributed throughout the tumor volume except in regions of necrosis. Even vessels containing no measurable oxygen remained perfused, as evidenced by the presence of the fluorescent marker. These results demonstrate that nicotinamide raises intravascular HbO2 saturations in both KHT and SCCVII tumors. This increase in oxygen delivery is not evenly distributed throughout the tumor volume in spite of a uniform distribution of perfused blood vessels. Blood flow in a substantial proportion of these vessels is most likely not sufficiently rapid to serve a functional purpose in terms of oxygen supply to the surrounding tumor tissue. 15 refs., 4 figs

  19. Arterial oxygen saturation in Addis Ababa during diazepam-ketamine anaesthesia.

    Science.gov (United States)

    Streatfeild, K A; Gebremeskel, A

    1999-10-01

    Addis Ababa is situated at an altitude of approximately 8500 ft and has a barometric pressure of close to 570 mmHg. Arterial blood gas values during the administration of anaesthesia with spontaneous ventilation have not been extensively studied. During the period January to July 1993, oxygen saturation was determined in 46 unpremedicated patients prior to minor surgery. Following this, patients received diazepam 0.1-0.2 mg/kg and ketamine 2 mg/kg during which a clear airway was maintained and peripheral oximetry was monitored continuously. The SpO2 was recorded for each patient at one minute intervals until 5 minutes and thence at 7, 10 and 15 minutes. The average SpO2 decreased below 90% at 2, 3 and 4 minutes and of the 46 patients, 8 (17.3%) required additional oxygen when their saturation fell below 80%. It is concluded that airway management and supplemental oxygen should be available when using this technique. PMID:11961876

  20. Lung vital capacity and oxygen saturation in adults with cerebral palsy

    Directory of Open Access Journals (Sweden)

    Lampe R

    2014-12-01

    saturation, and between chest expansion and oxygen saturation was found. The scoliotic deformities of the spine were associated with an additional decrease in the vital capacity, but this did not affect blood oxygen supply. Conclusion: Despite the decreased chest expansion and the significantly reduced lung volume in adults with cerebral palsy, sufficient oxygen supply was registered. Keywords: disability, lung function, spirometry, chest expansion, pulse oximetry

  1. Nitric oxide formation from the reaction of nitrite with carp and rabbit hemoglobin at intermediate oxygen saturations

    DEFF Research Database (Denmark)

    Jensen, Frank Bo

    2008-01-01

    The nitrite reductase activity of deoxyhemoglobin has received much recent interest because the nitric oxide produced in this reaction may participate in blood flow regulation during hypoxia. The present study used spectral deconvolution to characterize the reaction of nitrite with carp and rabbit...... hemoglobin at different constant oxygen tensions that generate the full range of physiological relevant oxygen saturations. Carp is a hypoxia-tolerant species with very high hemoglobin oxygen affinity, and the high R-state character and low redox potential of the hemoglobin is hypothesized to promote NO...... generation from nitrite. The reaction of nitrite with deoxyhemoglobin leads to a 1 : 1 formation of nitrosylhemoglobin and methemoglobin in both species. At intermediate oxygen saturations, the reaction with deoxyhemoglobin is clearly favored over that with oxyhemoglobin, and the oxyhemoglobin reaction and...

  2. Definition, significance and measurement of quantities pertaining to the oxygen carrying properties of human blood

    NARCIS (Netherlands)

    Zijlstra, WG; Maas, AHJ; Moran, RF

    1996-01-01

    A consistent set of definitions is given of the principal quantities pertaining to the oxygen transport by the blood, and of their mutual relationships, in relation to the methods used in their measurement. At the core is the correct definition of oxygen saturation, the deviation of which has recent

  3. 丙泊酚在无痛上消化道内镜检查术中对血氧饱和度的影响%Effect of Propofol on heart rate and saturation of blood oxygen during upper gastrointestinal endoscopy examination

    Institute of Scientific and Technical Information of China (English)

    吴明; 霍惠峰; 周家华; 陈英良

    2011-01-01

    Objective To study the effect of Propofol on the saturation decline of blood oxygen in upper gastrointestinal endoscopy examination and the reason of decline. Methods Two hundred patients (103 men and 97 women) having received upper gastrointestinal endoscopy examination due to various reasons enrolled in this study. Anamnesis and anthropometric values of the patients were taken.Preoperative oxygen saturation, hemoglobin levels and heart rate were recorded. Patients with initial oxygen saturation level <90% were excluded. Patients were divided into two groups. The first group included 100 patients, who underwent endoscopic examination without sedation and the second group included 100 patients, who underwent endoscopic examination propofol 1~ 2mg/(kg · h-1) for sedation. Patients' oxygen saturation and heart rate were monitored from the oropharyngeal anesthesia sedation before the start till 1 minute after the operation. During the endoscopic examination, minimum oxygen saturation and maximum heart rate values were recorded. The duration of the oxygen saturation <90% was recorded throughout the procedure to determine the stage of endoscopy at that time.Results There were no differences between the 2 groups in body mass index, smoking, hemoglobin and basal maximum pulse rate, duration of endoscopy, minimum basal oxygen saturation, duration of hypoxia and time to hypoxia. Reduction of blood oxygen saturation had no relationship with gender,duration of the endoscopy, basal pulse rate and hemoglobin level, but it correlatied with smoking.Conclusion Propofol as a premedication is a reliable method for upper gastrointestinal endoscopy examination and does not produce additional risk of serious complications. However, smoking as a factor of oxygen saturation decrease should be taken into account in patients with upper gastrointestinal endoscopy.%目的 研究上消化道内镜术前使用丙泊酚进行镇静是否会导致氧饱和度下降,并分析导致氧

  4. Oxygenation and Blood Volume Periodic Waveforms in the Brain

    CERN Document Server

    Gersten, Alexander; Raz, Amir

    2011-01-01

    Results of an experiment are presented whose aim is to explore the relationship between respiration and cerebral oxygenation. Measurements of end tidal CO2 (EtCO2) were taken simultaneously with cerebral oxygen saturation (rSO2) using the INVOS Cerebral Oximeter of Somanetics. Due to the device limitations we could explore only subjects who could perform with a breathing rate of around 2/min or less. Six subjects were used who were experienced in yoga breathing techniques. They performed an identical periodic breathing exercise including periodicity of about 2/min. The results of all six subjects clearly show a periodic change of cerebral oxygenation with the same period as the breathing exercises. Similar periodic changes in blood volume index were observed as well.

  5. An in vivo evaluation of the change in the pulpal oxygen saturation after administration of preoperative anxiolytics and local anesthesia

    Science.gov (United States)

    P. Shetty, Krishna; V. Satish, Sarvepalli; Kilaru, Krishnarao; Chakravarthi Ponangi, Kalyana; M. Luke, Alexander; Neshangi, Srisha

    2016-01-01

    Background. Given the influence of systemic blood pressure on pulpal blood flow, anxiolytics prescribed may alter the pulpal blood flow along with the local anesthetic solution containing a vasoconstrictor. This study evaluated the impact of preoperative anxiolytics and vasoconstrictors in local anesthetic agents on pulpal oxygen saturation. Methods. Thirty anxious young healthy individuals with a mean age of 24 years were randomly selected using the Corah’s Dental Anxiety Scale (DAS). After checking the vital signs the initial pulpal oxygen saturation (initial SpO2) was measured using a pulse oximeter. Oral midzolam was administered at a dose of 7.5 mg. After 30 min, the vital signs were monitored and the pulpal oxygen saturation (anxiolytic SpO2) was measured. A total of 1.5 mL of 2% lidocaine with 1:200000 epinephrine was administered as buccal infiltration anesthesia and 10 min the final pulpal oxygen saturation (L.A SpO2) was measured. Results. The mean initial (SpO2) was 96.37% which significantly decreased to 90.76% (SpO2) after the administration of the anxiolytic agent. This drop was later accentuated to 85.17% (SpO2) after administration of local anesthetic solution. Statistical significance was set at P<0.0001. Conclusion. High concentrations of irritants may permeate dentin due to a considerable decrease in the pulpal blood flow from crown or cavity preparation. Therefore, maintaining optimal blood flow during restorative procedures may prevent pulpal injury. PMID:27092212

  6. An in vivo evaluation of the change in the pulpal oxygen saturation after administration of preoperative anxiolytics and local anesthesia.

    Science.gov (United States)

    P Shetty, Krishna; V Satish, Sarvepalli; Kilaru, Krishnarao; Chakravarthi Ponangi, Kalyana; M Luke, Alexander; Neshangi, Srisha

    2016-01-01

    Background. Given the influence of systemic blood pressure on pulpal blood flow, anxiolytics prescribed may alter the pulpal blood flow along with the local anesthetic solution containing a vasoconstrictor. This study evaluated the impact of preoperative anxiolytics and vasoconstrictors in local anesthetic agents on pulpal oxygen saturation. Methods. Thirty anxious young healthy individuals with a mean age of 24 years were randomly selected using the Corah's Dental Anxiety Scale (DAS). After checking the vital signs the initial pulpal oxygen saturation (initial SpO2) was measured using a pulse oximeter. Oral midzolam was administered at a dose of 7.5 mg. After 30 min, the vital signs were monitored and the pulpal oxygen saturation (anxiolytic SpO2) was measured. A total of 1.5 mL of 2% lidocaine with 1:200000 epinephrine was administered as buccal infiltration anesthesia and 10 min the final pulpal oxygen saturation (L.A SpO2) was measured. Results. The mean initial (SpO2) was 96.37% which significantly decreased to 90.76% (SpO2) after the administration of the anxiolytic agent. This drop was later accentuated to 85.17% (SpO2) after administration of local anesthetic solution. Statistical significance was set at P<0.0001. Conclusion. High concentrations of irritants may permeate dentin due to a considerable decrease in the pulpal blood flow from crown or cavity preparation. Therefore, maintaining optimal blood flow during restorative procedures may prevent pulpal injury. PMID:27092212

  7. Acrolein-Induced Increases in Blood Pressure and Heart Rate Are Coupled with Decreased Blood Oxygen Levels During Exposure in Hypertensive Rats

    Science.gov (United States)

    Exposure to air pollution increases the risk of cardiovascular morbidity and mortality, especially in individuals with pre-existing cardiovascular disease. Recent studies link exposure to air pollution with reduced blood oxygen saturation suggesting that hypoxia is a potential me...

  8. Vogt-Koyanagi-Harada综合征恢复期患者视网膜血管血氧饱和度与血管直径测量%The oxygen saturation and retinal blood vessel diameter in patients with convalescence Vogt-Koyanagi-Harada syndrome

    Institute of Scientific and Technical Information of China (English)

    乐毅; 张晓敏; 王梅艳; 陈曦腾; 杨锦; 李筱荣

    2015-01-01

    Objective To measure and analyze the oxygen saturation and retinal blood vessel diameter in the eyes of patients with convalescence Vogt-Koyanagi-Harada (VKH) syndrome.Methods In this cross-sectional study, 28 eyes of 14 patients with convalescence VKH syndrome (VKH group) and 20 eyes of 10 healthy subjects (control group) were enrolled.The oxygen saturation and retinal blood vessel diameter were detected by spectrophotometric oximetry unit.Retinal images were collected using filters with wavelengths of 570 nm and 600 nm in the darkroom by the same technologist and then the fused image was obtained.The oxygen saturation of retinal vessels was marked in different colors.The measurement was repeated 2-3 times for each patient, then take an average.A top-quality image in each eye was selected to detect the oxygen saturation and diameter of retinal vessel which located in 1.5-3.0 disc diameter from the optic disc.Image analysis and data acquisition were completed by another technologist.Results Retinal venous oxygen saturation was (54.34 ± 8.05) % in the VKH group and (60.007 ± 7.91) % in the control group.The former was lower than the latter, the difference wvas significant (t=2.443, P=0.017).The mean diameter of retinal arteries was (102.8±18.1) μm in the VKH group and (112.9±19.8) μm in the control group.The former was smaller than the latter, the difference was significant (t =2.406, P=0.018).There was no significant difference of the mean diameter of retinal veins, oxygen saturation of retinal arteries and the arterial-venous difference between two groups (t=-0.330, 0.804,-0.631;P=0.743, 0.403, 0.536).Conclusions Retinal venous oxygen saturation and the mean diameter of retinal arteries are significantly decreased in patients with VKH syndrome.There is no significant difference of diameter of retinal veins, oxygen saturation of retinal arteries and the arterial-venous difference between VKH syndrome patients and healthy subjects.%目的

  9. Retinopathy of prematurity and induced changes in arterial oxygen saturation with near infrared spectrophotometry: a retrospective cohort study

    Science.gov (United States)

    von Siebenthal, K.; Keel, M.; Dietz, V.; Fauchere, J. C.; Martin, X.; Wolf, Martin; Duc, G.; Bucher, H. U.

    1996-10-01

    Near-infrared spectrophotometry (NIRS) is a noninvasive method for measuring oxygenated and deoxygenated hemoglobin in the neonatal brain. Using oxygen as a tracer, it is possible to calculate cerebral blood flow (cbf) and hemoglobin concentration (cHbc), which corresponds to cerebral blood volume, by inducing small changes in arterial oxygen saturation. Variability of tcpO2 is considered to be associated with severe retinopathy of prematurity (ROP). A preliminary analysis without control found a 51 percent incidence of ROP in infants subjected to NIRS measurements whereas among infants who were not exposed to oxygen changes, only 29 percent developed ROP. A controlled study with matched pairs was performed. Thirty-nine premature newborns who had received NIRS recordings were matched with 39 out of 172 infants who had not received NIRS. Using this controlled study design there was no difference in the incidence and severity of ROP between the two groups. The conclusions are that: 1) small changes in oxygen saturation of 3 to 10 percent to measure cbf and cHbc did not increase the incidence or the degree of severity of ROP. 2) A controlled study design is important. Analyses of uncontrolled data would have led to the conclusion that oxygen changes as used with NIRS increase the risk of ROP.

  10. Nanoparticle-enhanced spectral photoacoustic tomography: effect of oxygen saturation and tissue heterogeneity

    Science.gov (United States)

    Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Pfefer, T. Joshua

    2016-03-01

    Molecular imaging for breast cancer detection, infectious disease diagnostics and preclinical animal research may be achievable through combined use of targeted exogenous agents - such as nanoparticles - and spectral Photoacoustic Tomography (PAT). However, tissue heterogeneity can alter fluence distributions and acoustic propagation, corrupting measured PAT absorption spectra and complicating in vivo nanoparticle detection and quantitation. Highly absorptive vascular structures represent a common confounding factor, and variations in vessel hemoglobin saturation (SO2) may alter spectral content of signals from adjacent/deeper regions. To evaluate the impact of this effect on PAT nanoparticle detectability, we constructed heterogeneous phantoms with well-characterized channel-inclusion geometries and biologically relevant optical and acoustic properties. Phantoms contained an array of tubes at several depths filled with hemoglobin solutions doped with varying concentrations of gold nanorods with an absorption peak at 780 nm. Both overlying and target network SO2 was tuned using sodium dithionite. Phantoms were imaged from 700 to 900 nm using a custom PAT system comprised of a tunable pulsed laser and a research-grade ultrasound system. Recovered nanoparticle spectra were analyzed and compared with results from both spectrophotometry and PAT data from waterimmersed tubes containing blood and nanoparticle solutions. Results suggested that nanoparticle selection for a given PAT application should take into account expected oxygenation states of both target blood vessel and background tissue oxygenation to achieve optimal performance.

  11. Oxygen saturations of medical inpatients in a Malawian hospital: cross-sectional study of oxygen supply and demand

    Directory of Open Access Journals (Sweden)

    Hywel-Gethin Tudur Evans

    2012-05-01

    Full Text Available Normal 0 false false false EN-GB JA X-NONE Oxygen is a World Health Organisation listed essential drug yet provision of oxygen in developing countries often fails to meet demand.  The aim of this study was to evaluate the need for supplementary oxygen against oxygen delivery capacity at a large teaching hospital in Malawi.  A cross‐sectional study of all adult medical inpatients and assessment of oxygen provision over a 24‐hour period was conducted.    144 patients were included in the study, 14 of whom met local and international criteria for oxygen therapy (oxygen saturations of <90%.  Four were receiving oxygen.  Of the 8 oxygen concentrators available, only 4 were functional.  In conclusion, we identified a need for oxygen that was greater than the supply.

  12. Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle

    Science.gov (United States)

    Gurley, Katelyn; Shang, Yu; Yu, Guoqiang

    2012-07-01

    This study investigates a method using novel hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] to obtain continuous, noninvasive measurement of absolute blood flow (BF), blood oxygenation, and oxygen consumption rate (\\Vdot O2) in exercising skeletal muscle. Healthy subjects (n=9) performed a handgrip exercise to increase BF and \\Vdot O2 in forearm flexor muscles, while a hybrid optical probe on the skin surface directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and THC), tissue oxygen saturation (StO2), relative BF (rBF), and relative oxygen consumption rate (r\\Vdot O2). The rBF and r\\Vdot O2 signals were calibrated with absolute baseline BF and \\Vdot O2 obtained through venous and arterial occlusions, respectively. Known problems with muscle-fiber motion artifacts in optical measurements during exercise were mitigated using a novel gating algorithm that determined muscle contraction status based on control signals from a dynamometer. Results were consistent with previous findings in the literature. This study supports the application of NIRS/DCS technology to quantitatively evaluate hemodynamic and metabolic parameters in exercising skeletal muscle and holds promise for improving diagnosis and treatment evaluation for patients suffering from diseases affecting skeletal muscle and advancing fundamental understanding of muscle and exercise physiology.

  13. Effect of chest physiotherapy on oxygen saturation in patients with cystic fibrosis.

    OpenAIRE

    Pryor, J A; Webber, B. A.; Hodson, M E

    1990-01-01

    Decreasing arterial oxygen saturation has been reported in patients with cystic fibrosis during postural drainage when this was combined with other manoeuvres, which did not, however, include thoracic expansion exercises or pauses for relaxation and breathing control. When these features were included in an active cycle of breathing techniques during postural drainage in 20 patients with cystic fibrosis there was no fall in arterial oxygen saturation during the procedure (mean values 87.1%, 8...

  14. Validity of retinal oxygen saturation analysis: Hyperspectral imaging in visible wavelength with fundus camera and liquid crystal wavelength tunable filter

    Science.gov (United States)

    Hirohara, Yoko; Okawa, Yoshitaka; Mihashi, Toshifumi; Yamaguchi, Tatsuo; Nakazawa, Naoki; Tsuruga, Yasuko; Aoki, Hiroyuki; Maeda, Naoyuki; Uchida, Ichiro; Fujikado, Takashi

    2007-05-01

    The purpose of this paper was to investigate the feasibility of a newly developed hyperspectral fundus imaging camera with a liquid crystal tunable filter. The intensities of different wavelengths of light transmitted through an artery, vein, and the area surrounding these vessels and reflected out were measured, and the differential spectral absorptions were analyzed. Measurements were made from 16 normal eyes and from two artificial capillaries. The ratios of absorption (ROA) of arteries to veins from 500 to 580 nm (range 1) and from 600 to 720 nm (range 2) were calculated. For all eyes, the ROArange1 was larger than ROArange2. The ROA obtained from the artificial capillary filled with blood saturated with oxygen or nitrogen was similar to that of simulated data of oxy- and deoxyhemoglobin extinction rate. Most ROAs of human eyes were lower than those of the simulated data and the artificial capillaries. Oxygen saturation analysis by hyperspectral fundus imaging of retinal vessels were qualitatively in agreement with the in vitro analysis or simulated values. However, further improvements are necessary to evaluate the oxygen saturation quantitatively in the retinal blood vessels.

  15. Improvement in retinal venous oxygen saturation after panretinal photocoagulation is predictive of progression of proliferative diabetic retinopathy

    DEFF Research Database (Denmark)

    Torp, Thomas Lee; Kawasaki, Ryo; Wong, Tien Yin;

    blood pressure was 152/84mmHg. Retinal arterial and venous saturation was 96.7% and 67.4%, respectively. Patients in Group 1 and 2 did not differ in baseline retinal arterial and venous oxygen saturation, number of laser spots delivered, total laser energy delivered, or change in retinal arterial oxygen...... PRP was independently associated with PDR-activity. This might reflect absence in reduction in vascular endothelial growth factor (VEGF) and could be a potential non-invasive marker of disease activity.......®; OD-OS GmbH, Berlin, Germany). At follow-up, WFA was used to evaluate PDR activity and patients were categorized into two groups: progression (Group 1, n=10) or stability/regression of PDR (Group 2, n=29). Retinal oximetry measurements were performed on optic disc centered images using the in...

  16. NOTE: A haemodynamic model for the physiological interpretation of in vivo measurements of the concentration and oxygen saturation of haemoglobin

    Science.gov (United States)

    Fantini, Sergio

    2002-09-01

    We present a model that describes the effect of physiological parameters such as the speed of blood flow, local oxygen consumption, capillary recruitment, and vascular dilation/constriction on the concentration and oxygen saturation of haemoglobin in tissue. This model can be used to guide the physiological interpretation of haemodynamic and oximetric data collected in vivo with techniques such as optical imaging, near-infrared spectroscopy and functional magnetic resonance imaging. In addition to providing a formal description of well-established results (exercise-induced hyperemia, reperfusion hyperoxia, decrease in the concentration of deoxyhaemoglobin induced by brain activity, measurement of arterial saturation by pulse oximetry, etc.), this model suggests that the superposition of asynchronous contributions from the arterial, capillary and venous haemoglobin compartments may be at the origin of observed out-of-phase oscillations of the oxyhaemoglobin and deoxyhaemoglobin concentrations in tissue.

  17. Cerebral oxygen saturation: graded response to carbon dioxide with isoxia and graded response to oxygen with isocapnia.

    Directory of Open Access Journals (Sweden)

    W Alan C Mutch

    Full Text Available BACKGROUND: Monitoring cerebral saturation is increasingly seen as an aid to management of patients in the operating room and in neurocritical care. How best to manipulate cerebral saturation is not fully known. We examined cerebral saturation with graded changes in carbon dioxide tension while isoxic and with graded changes in oxygen tension while isocapnic. METHODOLOGY/PRINCIPAL FINDINGS: The study was approved by the Research Ethics Board of the University Health Network at the University of Toronto. Thirteen studies were undertaken in healthy adults with cerebral oximetry by near infrared spectroscopy. End-tidal gas concentrations were manipulated using a model-based prospective end-tidal targeting device. End-tidal carbon dioxide was altered ±15 mmHg from baseline in 5 mmHg increments with isoxia (clamped at 110±4 mmHg. End-tidal oxygen was changed to 300, 400, 500, 80, 60 and 50 mmHg under isocapnia (37±2 mmHg. Twelve studies were completed. The end-tidal carbon dioxide versus cerebral saturation fit a linear relationship (R(2 = 0.92±0.06. The end-tidal oxygen versus cerebral saturation followed log-linear behaviour and best fit a hyperbolic relationship (R(2 = 0.85±0.10. Cerebral saturation was maximized in isoxia at end-tidal carbon dioxide of baseline +15 mmHg (77±3 percent. Cerebral saturation was minimal in isocapnia at an end-tidal oxygen tension of 50 mmHg (61±3 percent. The cerebral saturation during normoxic hypocapnia was equivalent to normocapnic hypoxia of 60 mmHg. CONCLUSIONS/SIGNIFICANCE: Hypocapnia reduces cerebral saturation to an extent equivalent to moderate hypoxia.

  18. A pilot study of a new spectrophotometry device to measure tissue oxygen saturation

    International Nuclear Information System (INIS)

    Tissue oxygen saturation (SO2) measurements have the potential for far wider use than at present but are limited by device availability and portability for many potential applications. A device based on a small, low-cost general-purpose spectrophotometer (the Harrison device) might facilitate wider use. The aim of this study was to compare the Harrison device with a commercial instrument, the LEA O2C. Measurements were carried out on the forearm and finger of 20 healthy volunteers, using a blood pressure cuff on the upper arm to induce different levels of oxygenation. Repeatability of both devices was assessed, and the Bland–Altman method was used to assess agreement between them. The devices showed agreement in overall tracking of changes in SO2. Test–retest agreement for the Harrison device was worse than for O2C, with SD repeatability of 10.6% (forearm) or 18.6% (finger). There was no overall bias between devices, but mean (SD) difference of 1.2 (11.8%) (forearm) or 4.4 (11.5%) (finger) were outside of a clinically acceptable range. Disagreements were attributed to the stability of the Harrison probe and the natural SO2 variations across the skin surface increasing the random error. Therefore, though not equivalent to the LEA O2C, a probe redesign and averaged measurements may help establish the Harrison device as a low cost alternative. (paper)

  19. Optical imaging of hemoglobin oxygen saturation using a small number of spectral images for endoscopic application.

    Science.gov (United States)

    Saito, Takaaki; Yamaguchi, Hiroshi

    2015-12-01

    Tissue hypoxia is associated with tumor and inflammatory diseases, and detection of hypoxia is potentially useful for their detailed diagnosis. An endoscope system that can optically observe hemoglobin oxygen saturation (StO2) would enable minimally invasive, real-time detection of lesion hypoxia in vivo. Currently, point measurement of tissue StO2 via endoscopy is possible using the commercial fiber-optic oximeter T-Stat, which is based on visible light spectroscopy at many wavelengths. For clinical use, however, imaging of StO2 is desirable to assess the distribution of tissue oxygenation around a lesion. Here, we describe our StO2 imaging technique based on a small number of wavelength ranges in the visible range. By assuming a homogeneous tissue, we demonstrated that tissue StO2 can be obtained independently from the scattering property and blood concentration of tissue using four spectral bands. We developed a prototype endoscope system and used it to observe tissue-simulating phantoms. The StO2 (%) values obtained using our technique agreed with those from the T-Stat within 10%. We also showed that tissue StO2 can be derived using three spectral band if the scattering property is fixed at preliminarily measured values. PMID:26720878

  20. Accuracy of the cylinder approximation for susceptometric measurement of intravascular oxygen saturation.

    Science.gov (United States)

    Li, Cheng; Langham, Michael C; Epstein, Charles L; Magland, Jeremy F; Wu, Jue; Gee, James; Wehrli, Felix W

    2012-03-01

    Susceptometry-based MR oximetry has previously been shown suitable for quantifying hemoglobin oxygen saturation in large vessels for studying vascular reactivity and quantification of global cerebral metabolic rate of oxygen utilization. A key assumption underlying this method is that large vessels can be modeled as long paramagnetic cylinders. However, bifurcations, tapering, noncircular cross-section, and curvature of these vessels produce substantial deviations from cylindrical geometry, which may lead to errors in hemoglobin oxygen saturation quantification. Here, the accuracy of the "long cylinder" approximation is evaluated via numerical computation of the induced magnetic field from 3D segmented renditions of three veins of interest (superior sagittal sinus, femoral and jugular vein). At a typical venous oxygen saturation of 65%, the absolute error in hemoglobin oxygen saturation estimated via a closed-form cylinder approximation was 2.6% hemoglobin oxygen saturation averaged over three locations in the three veins studied and did not exceed 5% for vessel tilt angles cylinder approximation underlying MR susceptometry-based oximetry of large vessels. PMID:21858859

  1. Impact of red blood cell transfusion on global and regional measures of oxygenation.

    Science.gov (United States)

    Roberson, Russell S; Bennett-Guerrero, Elliott

    2012-01-01

    Anemia is common in critically ill patients. Although the goal of transfusion of red blood cells is to increase oxygen-carrying capacity, there are contradictory results about whether red blood cell transfusion to treat moderate anemia (e.g., hemoglobin 7-10 g/dL) improves tissue oxygenation or changes outcomes. Whereas increasing levels of anemia eventually lead to a level of critical oxygen delivery, increased cardiac output and oxygen extraction are homeostatic mechanisms the body uses to prevent a state of dysoxia in the setting of diminished oxygen delivery due to anemia. In order for cardiac output to increase in the face of anemia, normovolemia must be maintained. Transfusion of red blood cells increases blood viscosity, which may actually decrease cardiac output (barring a state of hypovolemia prior to transfusion). Studies have generally shown that transfusion of red blood cells fails to increase oxygen uptake unless oxygen uptake/oxygen delivery dependency exists (e.g., severe anemia or strenuous exercise). Recently, near-infrared spectroscopy, which approximates the hemoglobin saturation of venous blood, has been used to investigate whether transfusion of red blood cells increases tissue oxygenation in regional tissue beds (e.g., brain, peripheral skeletal muscle). These studies have generally shown increases in near-infrared spectroscopy derived measurements of tissue oxygenation following transfusion. Studies evaluating the effect of transfusion on the microcirculation have shown that transfusion increases the functional capillary density. This article will review fundamental aspects of oxygen delivery and extraction, and the effects of red blood cell transfusion on tissue oxygenation as well as the microcirculation. PMID:22238040

  2. Oxygen saturation in free-diving whales: optical sensor development

    Science.gov (United States)

    Gutierrez-Herrera, Enoch; Vacas-Jacques, Paulino; Anderson, Rox; Zapol, Warren; Franco, Walfre

    2013-02-01

    Mass stranding of live whales has been explained by proposing many natural or human-related causes. Recent necropsy reports suggest a link between the mass stranding of beaked whales and the use of naval mid-frequency sonar. Surprisingly, whales have experienced symptoms similar to those caused by inert gas bubbles in human divers. Our goal is to develop a compact optical sensor to monitor the consumption of the oxygen stores in the muscle of freely diving whales. To this end we have proposed the use of a near-infrared phase-modulated frequency-domain spectrophotometer, in reflectance mode, to probe tissue oxygenation. Our probe consists of three main components: radiofrequency (RF) modulated light sources, a high-bandwidth avalanche photodiode with transimpedance amplifier, and a RF gain and phase detector. In this work, we concentrate on the design and performance of the light sensor, and its corresponding amplifier unit. We compare three state-of-the-art avalanche photodiodes: one through-hole device and two surface-mount detectors. We demonstrate that the gain due to the avalanche effect differs between sensors. The avalanche gain near maximum bias of the through-hole device exceeds by a factor of 2.5 and 8.3 that of the surface-mount detectors. We present the behavior of our assembled through-hole detector plus high-bandwidth transimpedance amplifier, and compare its performance to that of a commercially available module. The assembled unit enables variable gain, its phase noise is qualitatively lower, and the form factor is significantly smaller. Having a detecting unit that is compact, flexible, and functional is a milestone in the development of our tissue oxygenation tag.

  3. In-vivo continuous monitoring of mixed venous oxygen saturation by photoacoustic transesophageal echocardiography (Conference Presentation)

    Science.gov (United States)

    Li, Li; Subramaniam, Balachundhar; Aguirre, Aaron D.; Andrawes, Michael N.; Tearney, Guillermo J.

    2016-02-01

    Mixed venous oxygen saturation (SvO2), measured from pulmonary arteries, is a gold-standard measure of the dynamic balance between the oxygen supply and demand in the body. In critical care, continuous monitoring of SvO2 plays a vital role in early detection of circulatory shock and guiding goal-oriented resuscitation. In current clinical practice, SvO2 is measured by invasive pulmonary artery catheters (PAC), which are associated with a 10% risk of severe complications. To address the unmet clinical need for a non-invasive SvO2 monitor, we are developing a new technology termed photoacoustic transesophageal echocardiography (PA-TEE). PA-TEE integrates transesophageal echocardiography with photoacoustic oximetry, and enables continuous assessment of SvO2 through an esophageal probe that can be inserted into the body in a minimally invasive manner. We have constructed a clinically translatable PA-TEE prototype, which features a mobile OPO laser, a modified ultrasonography console and a dual-modality esophageal probe. Comprised of a rotatable acoustic array detector, a flexible optical fiber bundle and a light-integrating acoustic lens, the oximetric probe has an outer diameter smaller than 15 mm and will be tolerable for most patients. Through custom-made C++/Qt software, our device acquires and displays ultrasonic and photoacoustic images in real time to guide the deployment of the probe. SvO2 is calculated on-line and updated every second. PA-TEE has now been used to evaluate SvO2 in living swine. Our findings show that changing the fraction of oxygen in the inspired gas modulates SvO2 measured by PA-TEE. Statistic comparison between SvO2 measurements from PA-TEE in vivo the gold-standard laboratorial analysis on blood samples drawn from PACs will be presented.

  4. 体位干预对早产儿呼吸、血氧饱和度及胃肠功能的影响%Influence of position intervention on respiratory,blood oxygen saturation and gastrointestinal function of premature infants with respiratory

    Institute of Scientific and Technical Information of China (English)

    农翠林

    2013-01-01

    目的:探讨早产儿采取不同体位对呼吸、血氧饱和度及胃肠功能的影响.方法:选择我院NICU于2011年1~12月收治的72例早产极低体重儿,均置于配置水囊式鸟巢的保暖箱内交替取不同体位进行护理,观察交替卧位前后对呼吸、血氧饱和度及胃肠功能的影响.结果:入院7d内的早产儿体位干预前后发生呼吸暂停的次数差异无统计学意义(P>0.05),干预前后经皮测血氧饱和度<85%、胃潴留量>喂奶量1/3的例数比较,差异均有统计学意义(P<0.05).结论:交替取仰卧位、俯卧位、侧卧位并抬高头颈部15°~30°,可减少早产儿呼吸暂停和低氧血症的发生率,促进胃排空,有益于促进早产儿正常生理机能的生长发育.%Objective:To investigate the effects of premature infants take different positions on the respiratory and gastrointestinal function,oxygen saturation. Methods ;72 cases of very low birth weight premature infants in our hospital NIGU from January to December in 2011,they were placed in the allocation of water bag bird's nest warm box in different position alternately nursing, observation of effect of alternate position on respiration, blood oxygen saturation and gastrointestinal function. Results :Admission of 7 days in premature infant body position intervention after and before the onset of apnea frequency difference does not have statistical significance (P>0.05),before the intervention of transcutaneous SpO2 feeding quantity 1/3 cases more,the differences were statistically significant (P <0. 05). Conclusion: The alternate take up,down,lateral and elevation of head and neck 15° -30°,reduces apnea of prematurity and hypoxemia,promoting gastric emptying.it is beneficial to promote the normal physiological function of the growth and development of premature infants.

  5. Signals Analysis and Clinical Validation of Blood and Oxygen Data in Human Brain

    Institute of Scientific and Technical Information of China (English)

    LI Kai-yang; LIU Li-jun; WANG Xiang; QIN Zhao; XIE Ze-ping

    2005-01-01

    With a self-made near-infrared analytical instrument to blood and oxygen parameters in human brain, 80 cases in which 20 are healthy persons and 30are anaesthetised cases and others are patients with heart function lack is taken to examine, and the data of blood and oxygen in brain tissue were collected and analyzed by the method of power spectrum and correlation function. The results indicate that: (1) The average brain oxygen saturation of healthy persons and anaesthetised cases is about 80%, in accord with normal parameter of physiology. Contrastively, the average brain oxygen saturation of patients with heart function lack is 72. 8%, which is obviously less than that of healthy persons and anaesthetised cases. The probability of medical statistics is less than 0. 01. (2) The shapes of wave of brain blood and oxygen for the healthy person and the anaesthetised case reveal small periodical fluctuations with stable shape and base line, and the trend of increase or decrease of blood and oxygen parameters in brain tissue is synchronous and a phase reversal, but for the patient with heart function lack in a brain oxygen lack state, the shapes of wave are irregular. This is a hint that near infrared light passing through tissue can reflect the intuitionistic change of brain blood and oxygen parameters. (3) The power spectra of brain blood and oxygen for the healthy person and the anaesthetised case has a clear main peak, narrow bandwidth and perfect superposition each other, but the power spectra for the patient with heart function lack in a brain oxygen lack state is on the contrary. (4) The average cross correlation coefficient of brain blood and oxygen for healthy persons and anaesthetised cases is -0. 9825±0. 1027 close to -1. But the average cross correlation coefficient for patients with heart function lack in a brain oxygen lack state is merely -0. 8923± 0. 1035 which is obviously greater than -1 and the probability of medical statistics is less than 0. 01

  6. Coral calcification under daily oxygen saturation and pH dynamics reveals the important role of oxygen

    Directory of Open Access Journals (Sweden)

    Tim Wijgerde

    2014-05-01

    Full Text Available Coral reefs are essential to many nations, and are currently in global decline. Although climate models predict decreases in seawater pH (∼0.3 units and oxygen saturation (∼5 percentage points, these are exceeded by the current daily pH and oxygen fluctuations on many reefs (pH 7.8–8.7 and 27–241% O2 saturation. We investigated the effect of oxygen and pH fluctuations on coral calcification in the laboratory using the model species Acropora millepora. Light calcification rates were greatly enhanced (+178% by increased seawater pH, but only at normoxia; hyperoxia completely negated this positive effect. Dark calcification rates were significantly inhibited (51–75% at hypoxia, whereas pH had no effect. Our preliminary results suggest that within the current oxygen and pH range, oxygen has substantial control over coral growth, whereas the role of pH is limited. This has implications for reef formation in this era of rapid climate change, which is accompanied by a decrease in seawater oxygen saturation owing to higher water temperatures and coastal eutrophication.

  7. Optoacoustic measurements of human placenta and umbilical blood oxygenation

    Science.gov (United States)

    Nanovskaya, T. N.; Petrov, I. Y.; Petrov, Y.; Patrikeeva, S. L.; Ahmed, M. S.; Hankins, G. D. V.; Prough, D. S.; Esenaliev, R. O.

    2016-03-01

    Adequate oxygenation is essential for normal embryogenesis and fetal growth. Perturbations in the intrauterine oxidative environment during pregnancy are associated with several pathophysiological disorders such as pregnancy loss, preeclampsia, and intrauterine growth restriction. We proposed to use optoacoustic technology for monitoring placental and fetal umbilical blood oxygenation. In this work, we studied optoacoustic monitoring of oxygenation in placenta and umbilical cord blood ex vivo using technique of placenta perfusion. We used a medical grade, nearinfrared, tunable, optoacoustic system developed and built for oxygenation monitoring in blood vessels and in tissues. First, we calibrated the system for cord blood oxygenation measurements by using a CO-Oximeter (gold standard). Then we performed validation in cord blood circulating through the catheters localized on the fetal side of an isolated placental lobule. Finally, the oxygenation measurements were performed in the perfused placental tissue. To increase or decrease blood oxygenation, we used infusion of a gas mixture of 95% O2 + 5% CO2 and 95% N2 + 5% CO2, respectively. In placental tissue, up to four cycles of changes in oxygenation were performed. The optoacoustically measured oxygenation in circulating cord blood and in placental lobule closely correlated with the actual oxygenation data measured by CO-Oximeter. We plan to further test the placental and cord blood oxygenation monitoring with optoacoustics in animal and clinical studies.

  8. Determination of Oxygen Saturation and Photoplethysmogram from Near Infrared Scattering Images

    CERN Document Server

    Ri, Yong-U; Sin, Kye-Ryong

    2016-01-01

    The near infrared scattering images of human muscle include some information on bloodstream and hemoglobin concentration according to skin depth and time. This paper addressed a method of determining oxygen saturation and photoplethysmogram from the near infrared (NIR) scattering images of muscle. Depending on the modified Beer-Lambert Law and the diffuse scattering model of muscular tissue, we determined an extinction coefficient matrix of hemoglobin from the near infrared scattering images and analyzed distribution of oxygen saturation of muscle with a depth from the extinction coefficient matrix. And we determined a dynamic attenuation variation curve with respect to fragmentary image frames sensitive to bloodstream from scattering image frames of muscle with time and then obtained the photoplethysmogram and heart rate by Fourier transformation and inverse transformation. This method based on the NIR scattering images can be applied in measurement of an average oxygen saturation and photoplethysmogram even...

  9. Cerebral venous blood oxygenation monitoring during hyperventilation in healthy volunteers with a novel optoacoustic system

    Science.gov (United States)

    Petrov, Andrey; Prough, Donald S.; Petrov, Irene Y.; Petrov, Yuriy; Deyo, Donald J.; Henkel, Sheryl N.; Seeton, Roger; Esenaliev, Rinat O.

    2013-03-01

    Monitoring of cerebral venous oxygenation is useful to facilitate management of patients with severe or moderate traumatic brain injury (TBI). Prompt recognition of low cerebral venous oxygenation is a key to avoiding secondary brain injury associated with brain hypoxia. In specialized clinical research centers, jugular venous bulb catheters have been used for cerebral venous oxygenation monitoring and have demonstrated that oxygen saturation capnography. Good temporal correlation between decreases in optoacoustically measured SSS oxygenation and decreases in EtCO2 was obtained. Decreases in EtCO2 from normal values (35-45 mmHg) to 20-25 mmHg resulted in SSS oxygenation decreases by 3-10%. Intersubject variability of the responses may relate to nonspecific brain activation associated with voluntary hyperventilation. The obtained data demonstrate the capability of the optoacoustic system to detect in real time minor changes in the SSS blood oxygenation.

  10. Retinal hemodynamic oxygen reactivity assessed by perfusion velocity, blood oximetry and vessel diameter measurements

    DEFF Research Database (Denmark)

    Klefter, Oliver Niels; Lauritsen, Anne Øberg; Larsen, Michael

    2015-01-01

    PURPOSE: To test the oxygen reactivity of a fundus photographic method of measuring macular perfusion velocity and to integrate macular perfusion velocities with measurements of retinal vessel diameters and blood oxygen saturation. METHODS: Sixteen eyes in 16 healthy volunteers were studied at two...... perfusion velocities, short-term ICCs were 0.79-0.82 and long-term ICCs were 0.06-0.11. Intersession increases in blood glucose were associated with reductions in perfusion velocities (arterial p = 0.0067; venous p = 0.018). CONCLUSION: Oxygen reactivity testing supported that motion-contrast velocimetry is...... a valid method for assessing macular perfusion. Results were consistent with previous observations of hyperoxic blood flow reduction using blue field entoptic and laser Doppler velocimetry. Retinal perfusion seemed to be regulated around individual set points according to blood glucose levels...

  11. Monitorization of the effects of spinal anaesthesia on cerebral oxygen saturation in elder patients using near-infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    Aysegul Kusku

    2014-07-01

    Full Text Available OBJECTIVE: Central blockage provided by spinal anaesthesia enables realization of many surgical procedures, whereas hemodynamic and respiratory changes influence systemic oxygen delivery leading to the potential development of series of problems such as cerebral ischemia, myocardial infarction and acute renal failure. This study was intended to detect potentially adverse effects of hemodynamic and respiratory changes on systemic oxygen delivery using cerebral oxymetric methods in patients who underwent spinal anaesthesia. METHODS: Twenty-five ASA I-II Group patients aged 65-80 years scheduled for unilateral inguinal hernia repair under spinal anaesthesia were included in the study. Following standard monitorization baseline cerebral oxygen levels were measured using cerebral oximetric methods. Standardized Mini Mental Test (SMMT was applied before and after the operation so as to determine the level of cognitive functioning of the cases. Using a standard technique and equal amounts of a local anaesthetic drug (15 mg bupivacaine 5% intratechal blockade was performed. Mean blood pressure (MBP, maximum heart rate (MHR, peripheral oxygen saturation (SpO2 and cerebral oxygen levels (rSO2 were preoperatively monitored for 60 min. Pre- and postoperative haemoglobin levels were measured. The variations in data obtained and their correlations with the cerebral oxygen levels were investigated. RESULTS: Significant changes in pre- and postoperative measurements of haemoglobin levels and SMMT scores and intraoperative SpO2 levels were not observed. However, significant variations were observed in intraoperative MBP, MHR and rSO2 levels. Besides, a correlation between variations in rSO2, MBP and MHR was determined. CONCLUSION: Evaluation of the data obtained in the study demonstrated that post-spinal decline in blood pressure and also heart rate decreases systemic oxygen delivery and adversely effects cerebral oxygen levels. However, this downward change did

  12. Normative Values of Retinal Oxygen Saturation in Rhesus Monkeys: The Beijing Intracranial and Intraocular Pressure (iCOP) Study

    OpenAIRE

    Jing LI; Yang, Yiquan; Yang, Diya; Liu, Xiangxiang; Sun, Yunxiao; Wei, Shifei; Wang, Ningli

    2016-01-01

    Objective To study the normal values of the retinal oxygen saturation in Rhesus monkeys and to evaluated repeatability and reproducibility of retinal oxygen saturation measurements. Methods Eighteen adult Rhesus macaque monkeys were included in this experimental study. An Oxymap T1 retinal oximeter (Oxymap, Reykjavik, Iceland) was used to perform oximetry on all subjects. Global arterial (SaO2) and venous oxygen saturation (SvO2), arteriovenous difference in SO2 were measured. In the first ex...

  13. Higher offspring survival among Tibetan women with high oxygen saturation genotypes residing at 4,000 m

    OpenAIRE

    Beall, Cynthia M.; Song, Kijoung; Elston, Robert C.; Goldstein, Melvyn C.

    2004-01-01

    Here we test the hypothesis that high-altitude native resident Tibetan women with genotypes for high oxygen saturation of hemoglobin, and thus less physiological hypoxic stress, have higher Darwinian fitness than women with low oxygen saturation genotypes. Oxygen saturation and genealogical data were collected from residents of 905 households in 14 villages at altitudes of 3,800–4,200 m in the Tibet Autonomous Region along with fertility histories from 1,749 women. Segregation analysis confir...

  14. Oxygen saturation targets in infants with bronchiolitis (BIDS): a double-blind, randomised, equivalence trial

    OpenAIRE

    Cunningham, Steve; Rodriguez Carbonell, Aryelly; Adams, Tim; Boyd, Kathleen A; Butcher, Isabella; Enderby, Beth; MacLean, Morag; McCormick, Jonathan; Paton, James Y; Wee, Fiona; Thomas, Huw; Riding, Kay; Turner, Steve W.; Williams, Chris; McIntosh, Emma

    2015-01-01

    BACKGROUND: The American Academy of Pediatrics recommends a permissive hypoxaemic target for an oxygen saturation of 90% for children with bronchiolitis, which is consistent with the WHO recommendations for targets in children with lower respiratory tract infections. No evidence exists to support this threshold. We aimed to assess whether the 90% or higher target for management of oxygen supplementation was equivalent to a normoxic 94% or higher target for infants admitted to hospital with vi...

  15. Accuracy of the Cylinder Approximation for Susceptometric Measurement of Intravascular Oxygen Saturation

    OpenAIRE

    Li, Cheng; Langham, Michael C; Epstein, Charles L.; Magland, Jeremy F; Wu, Jue; Gee, James,; Wehrli, Felix W.

    2011-01-01

    Susceptometry-based MR oximetry has previously been shown suitable for quantifying hemoglobin oxygen saturation in large vessels for studying vascular reactivity and quantification of global cerebral metabolic rate of oxygen utilization. A key assumption underlying this method is that large vessels can be modeled as long paramagnetic cylinders. However, bifurcations, tapering, noncircular cross-section, and curvature of these vessels produce substantial deviations from cylindrical geometry, w...

  16. Clinical predictors of a low central venous oxygen saturation after major surgery: a prospective prevalence study.

    Science.gov (United States)

    Litton, E; Silbert, B; Ho, K M

    2015-01-01

    Optimising perioperative haemodynamic status may reduce postoperative complications. In this prospective prevalence study, we investigated the associations between standard haemodynamic parameters and a low central venous oxygen saturation (ScvO2) in patients after major surgery. A total of 201 patients requiring continuous arterial and central venous pressure monitoring after major surgery were recruited. Simultaneous arterial and central venous blood gases, haemodynamic and biochemical data and perfusion index were obtained from patients at a single time-point within 24 hours of surgery. A low ScvO2 (ventilation, mean arterial pressure, central venous pressure, haemoglobin concentrations, arterial pH and lactate concentrations, arterial oxygen (PaO2) and carbon dioxide tensions (PaCO2) were all associated with a low ScvO2 in the univariate analyses. In the multivariate analysis, only a higher perfusion index (odds ratio [OR] 0.87, 95% confidence interval [CI] 0.78 to 0.98), PaO2 (OR 0.98 per mmHg increment, 95% CI 0.97 to 0.99) and PaCO2 (OR 0.88 per mmHg increment, 95% CI 0.82 to 0.95) and a lower central venous pressure (OR 1.14 per mmHg increment, 95% CI 1.04 to 1.25) were significantly associated with a reduced risk of a low ScvO2, all in a linear fashion. In conclusion, PaO2, PaCO2, perfusion index and central venous pressure were significant predictors of a low ScvO2 in patients after major surgery including cardiac surgery. PMID:25579290

  17. Higher cerebral oxygen saturation may provide higher urinary output during continuous regional cerebral perfusion

    Directory of Open Access Journals (Sweden)

    Tomoyasu Takahiro

    2008-10-01

    Full Text Available Abstract Objective We examined the hypothesis that higher cerebral oxygen saturation (rSO2 during RCP is correlated with urinary output. Methods Between December 2002 and August 2006, 12 patients aged 3 to 61 days and weighing 2.6 to 3.4 kg underwent aortic arch repair with RCP. Urinary output and rSO2 were analyzed retrospectively. Data were assigned to either of 2 groups according to their corresponding rSO2: Group A (rSO2 ≦ 75% and Group B (rSO2 Results Seven and 5 patients were assigned to Group A and Group B, respectively. Group A was characterized by mean radial arterial pressure (37.9 ± 9.6 vs 45.8 ± 7.8 mmHg; P = 0.14 and femoral arterial pressure (6.7 ± 6.1 vs 20.8 ± 14.6 mmHg; P = 0.09 compared to Group B. However, higher urinary output during CPB (1.03 ± 1.18 vs 0.10 ± 0.15 ml·kg-1·h-1; P = 0.03. Furthermore our results indicate that a higher dose of Chlorpromazine was used in Group A (2.9 ± 1.4 vs 1.7 ± 1.0 mg/kg; P = 0.03. Conclusion Higher cerebral oxygenation may provide higher urinary output due to higher renal blood flow through collateral circulation.

  18. Evaluation of blood transfusion effects on mixed venous oxygen saturation and lactate levels in patients with SIRS/sepsis Avaliação dos efeitos da transfusão de sanguínea na saturação venosa mista e nos níveis de lactato em pacientes com SIRS/sepse

    Directory of Open Access Journals (Sweden)

    Bruno Franco Mazza

    2005-08-01

    Full Text Available PURPOSE: To evaluate the effects of red blood cell transfusion in patients with SIRS/sepsis who presented hemoglobin levels under 9.0 g/dL at intensive care unit admission, using two parameters of organ perfusion: mixed venous oxygen saturation and serum lactate levels. METHODS: All patients admitted to the intensive care unit with SIRS/sepsis, as defined by Consensus Conference in 1992, and hemoglobin levels under 9.0 g/dL were included. Hemoglobin levels, mixed venous oxygen saturation, and lactate levels were collected before red blood cell transfusion (pre-T and up to 1 hour after transfusion (post-T. These variables were analyzed through a paired t test, and results were considered significant if P OBJETIVOS: Avaliar o efeito da transfusão de hemáceas em pacientes com SIRS/sepse que apresentaram níveis de hemoglobina abaixo de 9,0g/dL durante internação em unidade de terapia intensiva, usando dois parâmetros de perfusão orgânica, a saturação venosa mista de oxigênio e os níveis de lactato sérico. MÉTODOS: Todos os pacientes admitidos na Unidade de Terapia Intensiva com SIRS/sepse, como definido pela Conferência de Consenso de 1992, e níveis de hemoglobina abaixo de 9,0g/dL foram incluídos. Os níveis de hemoglobina, saturação venosa mista de oxigênio e lactato sérico foram coletados antes (pré-T e após uma hora da transfusão de hemáceas (pós-T. Essas variáveis foram analisadas através do teste T de Student pareado e os resultados considerados significativos se p<0,05. RESULTADOS: Vinte e nove pacientes (17 homens e 12 mulheres com idade média de 61,9±15,1 anos (21-85anos e índice APACHE II de 12.5±3.75 (7-21 foram transfundidos com uma média de 1,41 unidades de hemáceas. Um aumento significativo dos níveis de hemoglobina foi atingido com a transfusão: 8,14g/dL±0,64 (pré-T e 9,4±0,33g/dL (pós-T, com p<0,0001. Entretanto, isso não foi acompanhado por mudança significativa dos níveis de lactato: 1,87

  19. Development of A Blood Oxygen Saturation and Heart Rate Signal Collector of Sleeping Environment Regulating System%睡眠环境调节系统的血氧饱和度与心率信号采集环节研制

    Institute of Scientific and Technical Information of China (English)

    黄俊杰; 孙骁; 刘燕; 黄耀樑

    2012-01-01

    Sleep is the rest stage for energy recovery and storage after daily activities The sleep quality in this stage is closely related to health Temperature, humidity, oxygen content, noise, illumination, anion, etc of the sleeping environment are connected with the sleep quality tightly In order to gain better sleep effect, it is necessary to provide sleeping environment which can be automatically adjusted according to physiological parameters This paper designs the blood oxygen saturation and heart rate signal collector using MSP430F2274 and CC2500 as core module based on the development tool eZ430-RF2500 from Texas Instruments, achieves to collect process and wirelessly transmit pulse signals, and provides measurement methods of physiological parameters for the sleeping environment regulating system%睡眠是人在一天活动后进行精力恢复和能量贮存的休复阶段.该阶段的睡眠质量好坏与身体健康密切相关,而睡眠环境的温度、湿度、氧含量、噪音、光照、负离子等与睡眠质量有着紧密的联系.为了让人可以获得最佳睡眠效果,有必要提供可根据人体生理参数进行自动调节的睡眠环境.基于TI公司的eZ430-RF2500开发工具,设计开发了以MSP430F2274芯片和CC2500芯片为核心模块的血氧与心率信号检测环节,实现对脉搏波信号的采集、处理与无线发送,为睡眠环境调节系统提供前级人体生理参数的测量手段.

  20. Blood flow and oxygenation in peritendinous tissue and calf muscle during dynamic exercise in humans

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Langberg, H; Green, Sara Marie Ehrenreich;

    2000-01-01

    1. Circulation around tendons may act as a shunt for muscle during exercise. The perfusion and oxygenation of Achilles' peritendinous tissue was measured in parallel with that of calf muscle during exercise to determine (1) whether blood flow is restricted in peritendinous tissue during exercise...... output by dye dilution, arterial pressure by an arterial catheter-transducer, and muscle and peritendinous O2 saturation by spatially resolved spectroscopy (SRS). 3. Calf blood flow rose 20-fold with exercise, reaching 44 +/- 7 ml (100 g)-1 min-1 (mean +/- s.e.m. ) at 9 W, while Achilles' peritendinous...... with a rise in leg vascular conductance and microvascular haemoglobin volume, despite elevated systemic vascular resistance. 4. The parallel rise in calf muscle and peritendinous blood flow and fall in O2 saturation during exercise indicate that blood flow is coupled to oxidative metabolism in both...

  1. Oxygen diffusion-concentration in phospholipidic model membranes. An ESR-saturation study

    International Nuclear Information System (INIS)

    Fully hydrated liposomes of dipalmitoyl-phosphatidylcholine were labelled with 5 (or 7, 10, 12, 16)-doxyl stearic acid at pH 6 and 8, and studied by the continuous wave ESR-saturation technique. The ESR spectral magnitude depends on the hyperfrequency power P and on both T1 and T2 relaxation times. Saturation, i.e. the non linearity of the spectral magnitude plotted versus √P can be quantified by a P1/2 parameter (power at which the signal is half as great as it would be without saturation). If we assume T2 weakly modified by spin exchange between paramagnetic spin probe and oxygen in triplet state, P1/2 is inversely proportional to T1, and becomes a sensitive parameter to appreciate the oxygen transport (oxygen diffusion-concentration product) inside the bilayers. According to the DPPC bilayer phase transition diagrams, P1/2 (oxygen diffusion-concentration) is related to the thermodynamic state of the membrane. This technique provides further informations on a particular property of a radioprotective agent, cysteamine, which seems to inhibit spin-triplet exchange and hence maximizes T1 (minimizes P1/2). Since radioprotective agents are known to act by scavenging radiation-induced free radicals and by inhibiting oxygen-dependent free radical processes, such a result may contribute to elucidate radioprotecting mechanisms

  2. Brain magnetic resonance imaging with contrast dependent on blood oxygenation

    International Nuclear Information System (INIS)

    Paramagnetic deoxyhemoglobin in venous blood is a naturally occurring contrast agent for magnetic resonance imaging (MRI). By accentuating the effects of this agent through the use of gradient-echo techniques in high yields, the authors demonstrate in vivo images of brain microvasculature with image contrast reflecting the blood oxygen level. This blood oxygenation level-dependent (BOLD) contrast follows blood oxygen changes induced by anesthetics, by insulin-induced hypoglycemia, and by inhaled gas mixtures that alter metabolic demand or blood flow. The results suggest that BOLD contrast can be used to provide in vivo real-time maps of blood oxygenation in the brain under normal physiological conditions. BOLD contrast adds an additional feature to magnetic resonance imaging and complement other techniques that are attempting to provide position emission tomography-like measurements related to regional neural activity

  3. Brain magnetic resonance imaging with contrast dependent on blood oxygenation

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, S.; Lee, T.M.; Kay, A.R.; Tank, D.W. (AT and T Bell Laboratories, Murray Hill, NJ (United States))

    1990-12-01

    Paramagnetic deoxyhemoglobin in venous blood is a naturally occurring contrast agent for magnetic resonance imaging (MRI). By accentuating the effects of this agent through the use of gradient-echo techniques in high yields, the authors demonstrate in vivo images of brain microvasculature with image contrast reflecting the blood oxygen level. This blood oxygenation level-dependent (BOLD) contrast follows blood oxygen changes induced by anesthetics, by insulin-induced hypoglycemia, and by inhaled gas mixtures that alter metabolic demand or blood flow. The results suggest that BOLD contrast can be used to provide in vivo real-time maps of blood oxygenation in the brain under normal physiological conditions. BOLD contrast adds an additional feature to magnetic resonance imaging and complement other techniques that are attempting to provide position emission tomography-like measurements related to regional neural activity.

  4. Hematocrit and oxygenation dependence of blood (1)H(2)O T(1) at 7 Tesla.

    Science.gov (United States)

    Grgac, Ksenija; van Zijl, Peter C M; Qin, Qin

    2013-10-01

    Knowledge of blood (1)H2O T1 is critical for perfusion-based quantification experiments such as arterial spin labeling and cerebral blood volume-weighted MRI using vascular space occupancy. The dependence of blood (1)H2O T1 on hematocrit fraction (Hct) and oxygen saturation fraction (Y) was determined at 7 T using in vitro bovine blood in a circulating system under physiological conditions. Blood (1)H2O R1 values for different conditions could be readily fitted using a two-compartment (erythrocyte and plasma) model, which are described by a monoexponential longitudinal relaxation rate constant dependence. It was found that T1 = 2171 ± 39 ms for Y = 1 (arterial blood) and 2010 ± 41 ms for Y = 0.6 (venous blood), for a typical Hct of 0.42. The blood (1)H2O T1 values in the normal physiological range (Hct from 0.35 to 0.45, and Y from 0.6 to 1.0) were determined to range from 1900 to 2300 ms. The influence of oxygen partial pressure (pO2) and the effect of plasma osmolality for different anticoagulants were also investigated. It is discussed why blood (1)H2O T1 values measured in vivo for human blood may be about 10-20% larger than found in vitro for bovine blood at the same field strength. PMID:23169066

  5. An upgraded camera-based imaging system for mapping venous blood oxygenation in human skin tissue

    Science.gov (United States)

    Li, Jun; Zhang, Xiao; Qiu, Lina; Leotta, Daniel F.

    2016-07-01

    A camera-based imaging system was previously developed for mapping venous blood oxygenation in human skin. However, several limitations were realized in later applications, which could lead to either significant bias in the estimated oxygen saturation value or poor spatial resolution in the map of the oxygen saturation. To overcome these issues, an upgraded system was developed using improved modeling and image processing algorithms. In the modeling, Monte Carlo (MC) simulation was used to verify the effectiveness of the ratio-to-ratio method for semi-infinite and two-layer skin models, and then the relationship between the venous oxygen saturation and the ratio-to-ratio was determined. The improved image processing algorithms included surface curvature correction and motion compensation. The curvature correction is necessary when the imaged skin surface is uneven. The motion compensation is critical for the imaging system because surface motion is inevitable when the venous volume alteration is induced by cuff inflation. In addition to the modeling and image processing algorithms in the upgraded system, a ring light guide was used to achieve perpendicular and uniform incidence of light. Cross-polarization detection was also adopted to suppress surface specular reflection. The upgraded system was applied to mapping of venous oxygen saturation in the palm, opisthenar and forearm of human subjects. The spatial resolution of the oxygenation map achieved is much better than that of the original system. In addition, the mean values of the venous oxygen saturation for the three locations were verified with a commercial near-infrared spectroscopy system and were consistent with previously published data.

  6. Blood oxygenation level dependent (BOLD). Renal imaging. Concepts and applications

    International Nuclear Information System (INIS)

    Many renal diseases as well as several pharmacons cause a change in renal blood flow and/or renal oxygenation. The blood oxygenation level dependent (BOLD) imaging takes advantage of local field inhomogeneities and is based on a T2*-weighted sequence. BOLD is a non-invasive method allowing an estimation of the renal, particularly the medullary oxygenation, and an indirect measurement of blood flow without administration of contrast agents. Thus, effects of different drugs on the kidney and various renal diseases can be controlled and observed. This work will provide an overview of the studies carried out so far and identify ways how BOLD can be used in clinical studies. (orig.)

  7. Modular continuous wavelet processing of biosignals: extracting heart rate and oxygen saturation from a video signal.

    Science.gov (United States)

    Addison, Paul S

    2016-06-01

    A novel method of extracting heart rate and oxygen saturation from a video-based biosignal is described. The method comprises a novel modular continuous wavelet transform approach which includes: performing the transform, undertaking running wavelet archetyping to enhance the pulse information, extraction of the pulse ridge time-frequency information [and thus a heart rate (HRvid) signal], creation of a wavelet ratio surface, projection of the pulse ridge onto the ratio surface to determine the ratio of ratios from which a saturation trending signal is derived, and calibrating this signal to provide an absolute saturation signal (SvidO2). The method is illustrated through its application to a video photoplethysmogram acquired during a porcine model of acute desaturation. The modular continuous wavelet transform-based approach is advocated by the author as a powerful methodology to deal with noisy, non-stationary biosignals in general. PMID:27382479

  8. Modular continuous wavelet processing of biosignals: extracting heart rate and oxygen saturation from a video signal

    Science.gov (United States)

    2016-01-01

    A novel method of extracting heart rate and oxygen saturation from a video-based biosignal is described. The method comprises a novel modular continuous wavelet transform approach which includes: performing the transform, undertaking running wavelet archetyping to enhance the pulse information, extraction of the pulse ridge time–frequency information [and thus a heart rate (HRvid) signal], creation of a wavelet ratio surface, projection of the pulse ridge onto the ratio surface to determine the ratio of ratios from which a saturation trending signal is derived, and calibrating this signal to provide an absolute saturation signal (SvidO2). The method is illustrated through its application to a video photoplethysmogram acquired during a porcine model of acute desaturation. The modular continuous wavelet transform-based approach is advocated by the author as a powerful methodology to deal with noisy, non-stationary biosignals in general. PMID:27382479

  9. Oxygen saturation imaging of human retinal vessels and measurement in eye disease patient for clinical application

    Science.gov (United States)

    Nakamura, D.; Matsuoka, N.; Tatsuguchi, K.; Ogata, M.; Yoshinaga, Y.; Enaida, H.; Okada, T.; Ishibashi, T.

    2010-02-01

    We have proposed a new automatic visualization procedure based the ratio of optical densities (ODs) obtained at two different wavelength for the oxygen saturation imaging in human retinal vessels. This method utilized the morphological processing and the line convergence index filter to estimate the reflection image of outside vessels and extract the vessel structure from retinal image, respectively. In the experimental measurement, clear difference between retinal arteries and veins has been observed. In this study, the data processing technique of the line convergence index filter was applied to a color fundus image to investigate the ability of vessel extraction. In addition, four-wavelength imaging was proposed to evaluate oxygen saturation of the retinal capillary vessels and to decrease the influence of the melanin pigmentation.

  10. Photoirradiation system with depth optical dosimetry control in initial oxygen saturation measurement

    International Nuclear Information System (INIS)

    Photodynamic Therapy is a technique in which a photosensitizing substance is applied that is activated by light and it generates reactive oxygen species which cause selective cell destruction. The efficiency of the therapy is affected by the parameters dose. In this work it is shown a photo-irradiation system for superficial Photodynamic Therapy, using as a light source a light emitting diode with an automatic control of optical power based on a model of the distribution of light in depth that was tested in tissue phantoms. It also has a reflective pulse oximeter for the measurement of the initial oxygen saturation. (Author)

  11. Safe oxygen saturation targeting and monitoring in preterm infants: can we avoid hypoxia and hyperoxia?

    Science.gov (United States)

    Sola, Augusto; Golombek, Sergio G; Montes Bueno, María Teresa; Lemus-Varela, Lourdes; Zuluaga, Claudia; Domínguez, Fernando; Baquero, Hernando; Young Sarmiento, Alejandro E; Natta, Diego; Rodriguez Perez, Jose M; Deulofeut, Richard; Quiroga, Ana; Flores, Gabriel Lara; Morgues, Mónica; Pérez, Alfredo García-Alix; Van Overmeire, Bart; van Bel, Frank

    2014-01-01

    Oxygen is a neonatal health hazard that should be avoided in clinical practice. In this review, an international team of neonatologists and nurses assessed oxygen saturation (SpO2) targeting in preterm infants and evaluated the potential weaknesses of randomised clinical trials. Conclusion SpO2 of 85–89% can increase mortality and 91–95% can cause hyperoxia and ill effects. Neither of these ranges can be recommended, and wider intermediate targets, such as 87–94% or 88–94%, may be safer. PMID:24838096

  12. Safe oxygen saturation targeting and monitoring in preterm infants: can we avoid hypoxia and hyperoxia?

    OpenAIRE

    Sola, Augusto; Golombek, Sergio G.; Montes Bueno, María Teresa; Lemus-Varela, Lourdes; Zuluaga, Claudia; Domínguez, Fernando; Baquero, Hernando; Young Sarmiento, Alejandro E; Natta, Diego; Rodriguez Perez, Jose M; Deulofeut, Richard; Quiroga, Ana; Flores, Gabriel Lara; Morgues, Mónica; Pérez, Alfredo García-Alix

    2014-01-01

    Oxygen is a neonatal health hazard that should be avoided in clinical practice. In this review, an international team of neonatologists and nurses assessed oxygen saturation (SpO2) targeting in preterm infants and evaluated the potential weaknesses of randomised clinical trials. Conclusion SpO2 of 85–89% can increase mortality and 91–95% can cause hyperoxia and ill effects. Neither of these ranges can be recommended, and wider intermediate targets, such as 87–94% or 88–94%, may be safer.

  13. The Extended Oxygen Window Concept for Programming Saturation Decompressions Using Air and Nitrox.

    Directory of Open Access Journals (Sweden)

    Jacek Kot

    Full Text Available Saturation decompression is a physiological process of transition from one steady state, full saturation with inert gas at pressure, to another one: standard conditions at surface. It is defined by the borderline condition for time spent at a particular depth (pressure and inert gas in the breathing mixture (nitrogen, helium. It is a delicate and long lasting process during which single milliliters of inert gas are eliminated every minute, and any disturbance can lead to the creation of gas bubbles leading to decompression sickness (DCS. Most operational procedures rely on experimentally found parameters describing a continuous slow decompression rate. In Poland, the system for programming of continuous decompression after saturation with compressed air and nitrox has been developed as based on the concept of the Extended Oxygen Window (EOW. EOW mainly depends on the physiology of the metabolic oxygen window--also called inherent unsaturation or partial pressure vacancy--but also on metabolism of carbon dioxide, the existence of water vapor, as well as tissue tension. Initially, ambient pressure can be reduced at a higher rate allowing the elimination of inert gas from faster compartments using the EOW concept, and maximum outflow of nitrogen. Then, keeping a driving force for long decompression not exceeding the EOW allows optimal elimination of nitrogen from the limiting compartment with half-time of 360 min. The model has been theoretically verified through its application for estimation of risk of decompression sickness in published systems of air and nitrox saturation decompressions, where DCS cases were observed. Clear dose-reaction relation exists, and this confirms that any supersaturation over the EOW creates a risk for DCS. Using the concept of the EOW, 76 man-decompressions were conducted after air and nitrox saturations in depth range between 18 and 45 meters with no single case of DCS. In summary, the EOW concept describes

  14. Monitoring cerebral oxygen saturation during cardiopulmonary bypass using near-infrared spectroscopy: the relationships with body temperature and perfusion rate

    Science.gov (United States)

    Teng, Yichao; Ding, HaiShu; Gong, Qingcheng; Jia, Zaishen; Huang, Lan

    2006-03-01

    During cardiopulmonary bypass (CPB) because of weak arterial pulsation, near-IR spectroscopy (NIRS) is almost the only available method to monitor cerebral oxygenation noninvasively. Our group develops a NIRS oximeter to monitor regional cerebral oxygenation especially its oxygen saturation (rScO2). To achieve optimal coupling between the sensor and human brain, the distances between the light source and the detectors on it are properly chosen. The oximeter is calibrated by blood gas analysis, and the results indicate that its algorithm is little influenced by either background absorption or overlying tissue. We used it to measure the rScO2 of 15 patients during CPB. It is shown that rScO2 is negatively correlated with body temperature and positively with perfusion rate. There are two critical stages during CPB when rScO2 might be relatively low: one is the low-perfusion-rate stage, the other is the early rewarming stage. During cooling, the changes of total hemoglobin concentration (CtHb) compared with its original value is also monitored. It is shown that CtHb decreases to a small extent, which may mainly reflect cerebral vasoconstriction induced by cooling. All these results indicate that NIRS can be used to monitor cerebral oxygenation to protect cerebral tissue during CPB.

  15. Determination of Oxygen Saturation and Photoplethysmogram from Near Infrared Scattering Images

    OpenAIRE

    Ri, Yong-U; Pyon, Young-Hui; Sin, Kye-Ryong

    2016-01-01

    The near infrared scattering images of human muscle include some information on bloodstream and hemoglobin concentration according to skin depth and time. This paper addressed a method of determining oxygen saturation and photoplethysmogram from the near infrared (NIR) scattering images of muscle. Depending on the modified Beer-Lambert Law and the diffuse scattering model of muscular tissue, we determined an extinction coefficient matrix of hemoglobin from the near infrared scattering images ...

  16. A novel method based on two cameras for accurate estimation of arterial oxygen saturation

    OpenAIRE

    Liu, He; Ivanov, Kamen; Wang, Yadong; Wang, Lei

    2015-01-01

    Background Photoplethysmographic imaging (PPGi) that is based on camera allows acquiring photoplethysmogram and measuring physiological parameters such as pulse rate, respiration rate and perfusion level. It has also shown potential for estimation of arterial oxygen saturation (SaO2). However, there are some technical limitations such as optical shunting, different camera sensitivity to different light spectra, different AC-to-DC ratios (the peak-to-peak amplitude to baseline ratio) of the PP...

  17. Optical noninvasive calculation of hemoglobin components concentrations and fractional oxygen saturation using a ring-scattering pulse oximeter

    Science.gov (United States)

    Abdallah, Omar; Stork, Wilhelm; Muller-Glaser, Klaus

    2004-06-01

    The deficiencies of the currently used pulse oximeter are discussed in diverse literature. A hazardous pitfalls of this method is that the pulse oximeter will not detect carboxyhemoglobin (COHb) and methemoglobin (metHb) concentrations. This leads to incorrect measurement of oxygen saturation by carbon monoxide poisoning and methemoglobinemia. Also the total hemoglobin concentration will not be considered and can only be measured in-vitro up to now. A second pitfall of the standard pulse oximetry is that it will not be able to show a result by low perfusion of tissues. This case is available inter alia when the patient is under shock or has a low blood pressure. The new non-invasive system we designed measures the actual (fractional) oxygen saturation and hemoglobin concentration. It will enable us also to measure COHb and metHb. The measurement can be applied at better perfused body central parts. Four or more light emitting diodes (LEDs) or laser diodes (LDs) and five photodiodes (PDs) are used. The reflected light signal detected by photodiodes is processed using a modified Lambert-Beer law (I=I0×e-α.d ). According to this law, when a non scattering probe is irradiated with light having the incident intensity I0, the intensity of transmitted light I decays exponentially with the absorption coefficient a of that probe and its thickness d. Modifications of this law have been performed following the theoretical developed models in literature, Monte Carlo simulation and experimental measurement.

  18. Oxygen Saturation and RR Intervals Feature Selection for Sleep Apnea Detection

    Directory of Open Access Journals (Sweden)

    Antonio G. Ravelo-García

    2015-05-01

    Full Text Available A diagnostic system for sleep apnea based on oxygen saturation and RR intervals obtained from the EKG (electrocardiogram is proposed with the goal to detect and quantify minute long segments of sleep with breathing pauses. We measured the discriminative capacity of combinations of features obtained from RR series and oximetry to evaluate improvements of the performance compared to oximetry-based features alone. Time and frequency domain variables derived from oxygen saturation (SpO2 as well as linear and non-linear variables describing the RR series have been explored in recordings from 70 patients with suspected sleep apnea. We applied forward feature selection in order to select a minimal set of variables that are able to locate patterns indicating respiratory pauses. Linear discriminant analysis (LDA was used to classify the presence of apnea during specific segments. The system will finally provide a global score indicating the presence of clinically significant apnea integrating the segment based apnea detection. LDA results in an accuracy of 87%; sensitivity of 76% and specificity of 91% (AUC = 0.90 with a global classification of 97% when only oxygen saturation is used. In case of additionally including features from the RR series; the system performance improves to an accuracy of 87%; sensitivity of 73% and specificity of 92% (AUC = 0.92, with a global classification rate of 100%.

  19. Functional photoacoustic tomography for non-invasive imaging of cerebral blood oxygenation and blood volume in rat brain in vivo

    Science.gov (United States)

    Wang, Xueding; Xie, Xueyi; Ku, Geng; Stoica, George; Wang, Lihong V.

    2005-04-01

    Based on the multi-wavelength laser-based photoacoustic tomography, non-invasive in vivo imaging of functional parameters, including the hemoglobin oxygen saturation and the total concentration of hemoglobin, in small-animal brains was realized. The high sensitivity of this technique is based on the spectroscopic differences between oxy- and deoxy-hemoglobin while its spatial resolution is bandwidth-limited by the photoacoustic signals rather than by the optical diffusion as in optical imaging. The point-by-point distributions of blood oxygenation and blood volume in the cerebral cortical venous vessels, altered by systemic physiological modulations including hyperoxia, normoxia and hypoxia, were visualized successfully through the intact skin and skull. This technique, with its prominent intrinsic advantages, can potentially accelerate the progress in neuroscience and provide important new insights into cerebrovascular physiology and brain function that are of great significance to the neuroscience community.

  20. Cutaneous vasoconstriction affects near-infrared spectroscopy determined cerebral oxygen saturation during administration of norepinephrine

    DEFF Research Database (Denmark)

    Sørensen, Niels Henrik Breiner; Secher, Niels H; Siebenmann, Christoph;

    2012-01-01

    Perioperative optimization of spatially resolved near-infrared spectroscopy determined cerebral frontal lobe oxygenation (scO2) may reduce postoperative morbidity. Norepinephrine is routinely administered to maintain cerebral perfusion pressure and, thereby, cerebral blood flow, but norepinephrine...... reduces the scO2. We hypothesized that norepinephrine-induced reduction in scO2 is influenced by cutaneous vasoconstriction....

  1. The Relationship between Oxygen Saturation and Color Alteration of a Compromised Skin Flap: Experimental Study on the Rabbit

    Directory of Open Access Journals (Sweden)

    Theddeus O. H. Prasetyono

    2013-09-01

    Full Text Available Background The aim of this study was to collect important data on the time of oxygensaturation change in relation to skin flap color alteration using non-invasive pulse oximetryto evaluate its ability to provide continuous monitoring of skin flap perfusion.Methods An experimental study on the monitoring of blood perfusion of 20 tube-islandgroin flaps of 10 male New Zealand rabbits was performed using pulse oximetry. The animalswere randomly assigned to one of two groups representing a blockage of either arterial orvenous blood flow. The oxygen saturation change and clinical color alteration were monitoredfrom the beginning of vessel clamping until the saturation became undetectable. The resultwas analyzed by the t-test using SSPS ver. 10.0.Results The mean times from the vessel clamping until the saturation became undetectablewere 20.19±2.13 seconds and 74.91±10.57 seconds for the artery and vein clamping groups,respectively. The mean time of the clinical alteration from the beginning of vein clampingwas 34.5±11.72 minutes, while the alteration in flaps with artery clamping could not bedetected until 2.5 hours after clamping.Conclusions The use of neonate-type reusable flex sensor-pulse oximetry is objective andeffective in early detection of arterial and vein blockage. It provides real-time data on vesselocclusion, which in turn will allow for early salvaging. The detection periods of both arterialocclusion and venous congestion are much earlier than the color alteration one may encounterclinically.

  2. Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle

    OpenAIRE

    Gurley, Katelyn; Shang, Yu; Yu, Guoqiang

    2012-01-01

    This study investigates a method using novel hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] to obtain continuous, noninvasive measurement of absolute blood flow (BF), blood oxygenation, and oxygen consumption rate (V˙O2) in exercising skeletal muscle. Healthy subjects (n=9) performed a handgrip exercise to increase BF and V˙O2 in forearm flexor muscles, while a hybrid optical probe on the skin surface directly monitored oxy...

  3. Noninvasive optoacoustic monitoring of cerebral venous blood oxygenation in newborns

    Science.gov (United States)

    Petrov, Irene Y.; Wynne, Karon E.; Petrov, Yuriy; Esenaliev, Rinat O.; Richardson, C. Joan; Prough, Donald S.

    2012-02-01

    Cerebral ischemia after birth and during labor is a major cause of death and severe complications such as cerebral palsy. In the USA alone, cerebral palsy results in permanent disability of 10,000 newborns per year and approximately 500,000 of the total population. Currently, no technology is capable of direct monitoring of cerebral oxygenation in newborns. This study proposes the use of an optoacoustic technique for noninvasive cerebral ischemia monitoring by probing the superior sagittal sinus (SSS), a large central cerebral vein. We developed and built a multi-wavelength, near-infrared optoacoustic system suitable for noninvasive monitoring of cerebral ischemia in newborns with normal weight (NBW), low birth-weight (LBW, 1500 - 2499 g) and very low birth-weight (VLBW, neonatal intensive care unit. We performed single and continuous measurements of the SSS blood oxygenation. The data acquisition, processing and analysis software developed by our group provided real-time, absolute SSS blood oxygenation measurements. The SSS blood oxygenation ranged from 60% to 80%. Optoacoustic monitoring of the SSS blood oxygenation provides valuable information because adequate cerebral oxygenation would suggest that no therapy was necessary; conversely, evidence of cerebral ischemia would prompt therapy to increase cerebral blood flow.

  4. [Design of Oxygen Saturation, Heart Rate, Respiration Rate Detection System Based on Smartphone of Android Operating System].

    Science.gov (United States)

    Zhu, Mingshan; Zeng, Bixin

    2015-03-01

    In this paper, we designed an oxygen saturation, heart rate, respiration rate monitoring system based on smartphone of android operating system, physiological signal acquired by MSP430 microcontroller and transmitted by Bluetooth module. PMID:26524782

  5. Blood flow and oxygenation in peritendinous tissue and calf muscle during dynamic exercise in humans

    DEFF Research Database (Denmark)

    Boushel, R; Langberg, Henning; Green, Stefan Mathias; Skovgaard, D; Bulow, J; Kjaer, M

    1. Circulation around tendons may act as a shunt for muscle during exercise. The perfusion and oxygenation of Achilles' peritendinous tissue was measured in parallel with that of calf muscle during exercise to determine (1) whether blood flow is restricted in peritendinous tissue during exercise...... output by dye dilution, arterial pressure by an arterial catheter-transducer, and muscle and peritendinous O2 saturation by spatially resolved spectroscopy (SRS). 3. Calf blood flow rose 20-fold with exercise, reaching 44 +/- 7 ml (100 g)-1 min-1 (mean +/- s.e.m. ) at 9 W, while Achilles' peritendinous...... flow increased (7-fold) to 14 +/- 4 ml (100 g)-1 min-1, which was 18 % of the maximal flow established during reactive hyperaemia. SRS-O2 saturation fell both in muscle (from 66 +/- 2 % at rest to 57 +/- 3 %, P <0.05) and in peritendinous regions (58 +/- 4 to 52 +/- 4 %, P <0.05) during exercise along...

  6. Physiologic simulator to predict the arterial oxygen saturation at extreme heights

    OpenAIRE

    Arturo Reyes Lazalde; María Eugenia Pérez Bonilla; Olga Leticia Fuchs Gómez; Marleni Reyes Monreal

    2011-01-01

    A simulator («Alturas») was developed to calculate the levels of arterial oxygen saturation (SaO 2 ) at heights ranging from small to extreme. The results of the simulations were compared to published experimental data in order to validate the accuracy of the simulator. Three types of cases were used in the comparison: (1) non acclimatized people at heights ranging from 20 m to 4,162 m above sea level, (2) inhabitants of mountain zones living at heights between 1,692 m and 4,230 m, (3) ...

  7. Simultaneous measurement of oxygen flux and salinity of the water saturated mineral soils

    Directory of Open Access Journals (Sweden)

    Bieganowski A.

    2003-09-01

    Full Text Available This paper presents a possibility current-voltage curve interpretation, registered in the saturated soil, in categories of soil salinity evaluation. A quantity containing the information about the salinity is electric conductivity of the soil. This conductivity can be evaluated by the analysis of the slope of a straight line, fitted into the part of the current-voltage curve, which is responsible for the reduction of hydrogen ions during the electrolysis of the water contained in the soil. It gives a chance to evaluate simultaneously the oxygen flux density and the soil salinity in conditions of maximum humidity, i.e., in a situation, when the availability of oxygen is minimum and it can be a limitation of the plant growth and when the mobility of ions, dissolved in the soil solution is maximum.

  8. Influence of dissolved oxygen on silver nanoparticle mobility and dissolution in water-saturated quartz sand

    International Nuclear Information System (INIS)

    The influence of dissolved oxygen (DO) on the transport behavior and dissolution kinetics of silver nanoparticles (nAg) was explored through a combination of experimental and mathematical modeling studies. One-dimensional column experiments were conducted with water-saturated 40–50 mesh Ottawa sand, operated at pH 4 or 7 under three DO conditions (8.9, 2, or + from retained nanoparticles. Experimental observations revealed that the mobility of nAg increased by 15 % when the DO level was reduced from 8.9 to + decreased from 21.6 to 13.5 to 11.3 % with decreasing oxygen level (8.9, 2, and + release over time

  9. 21 CFR 868.1200 - Indwelling blood oxygen partial pressure (PO2) analyzer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Indwelling blood oxygen partial pressure (PO2... Indwelling blood oxygen partial pressure (PO2) analyzer. (a) Identification. An indwelling blood oxygen... electrode) and that is used to measure, in vivo, the partial pressure of oxygen in blood to aid...

  10. Oxygenation and Blood Volume Periodic Waveforms in the Brain

    OpenAIRE

    Gersten, Alexander; Heimer, Dov; Raz, Amir

    2011-01-01

    Results of an experiment are presented whose aim is to explore the relationship between respiration and cerebral oxygenation. Measurements of end tidal CO2 (EtCO2) were taken simultaneously with cerebral oxygen saturation (rSO2) using the INVOS Cerebral Oximeter of Somanetics. Due to the device limitations we could explore only subjects who could perform with a breathing rate of around 2/min or less. Six subjects were used who were experienced in yoga breathing techniques. They performed an i...

  11. Eigenspectra optoacoustic tomography achieves quantitative blood oxygenation imaging deep in tissues

    Science.gov (United States)

    Tzoumas, Stratis; Nunes, Antonio; Olefir, Ivan; Stangl, Stefan; Symvoulidis, Panagiotis; Glasl, Sarah; Bayer, Christine; Multhoff, Gabriele; Ntziachristos, Vasilis

    2016-06-01

    Light propagating in tissue attains a spectrum that varies with location due to wavelength-dependent fluence attenuation, an effect that causes spectral corruption. Spectral corruption has limited the quantification accuracy of optical and optoacoustic spectroscopic methods, and impeded the goal of imaging blood oxygen saturation (sO2) deep in tissues; a critical goal for the assessment of oxygenation in physiological processes and disease. Here we describe light fluence in the spectral domain and introduce eigenspectra multispectral optoacoustic tomography (eMSOT) to account for wavelength-dependent light attenuation, and estimate blood sO2 within deep tissue. We validate eMSOT in simulations, phantoms and animal measurements and spatially resolve sO2 in muscle and tumours, validating our measurements with histology data. eMSOT shows substantial sO2 accuracy enhancement over previous optoacoustic methods, potentially serving as a valuable tool for imaging tissue pathophysiology.

  12. Eigenspectra optoacoustic tomography achieves quantitative blood oxygenation imaging deep in tissues

    Science.gov (United States)

    Tzoumas, Stratis; Nunes, Antonio; Olefir, Ivan; Stangl, Stefan; Symvoulidis, Panagiotis; Glasl, Sarah; Bayer, Christine; Multhoff, Gabriele; Ntziachristos, Vasilis

    2016-01-01

    Light propagating in tissue attains a spectrum that varies with location due to wavelength-dependent fluence attenuation, an effect that causes spectral corruption. Spectral corruption has limited the quantification accuracy of optical and optoacoustic spectroscopic methods, and impeded the goal of imaging blood oxygen saturation (sO2) deep in tissues; a critical goal for the assessment of oxygenation in physiological processes and disease. Here we describe light fluence in the spectral domain and introduce eigenspectra multispectral optoacoustic tomography (eMSOT) to account for wavelength-dependent light attenuation, and estimate blood sO2 within deep tissue. We validate eMSOT in simulations, phantoms and animal measurements and spatially resolve sO2 in muscle and tumours, validating our measurements with histology data. eMSOT shows substantial sO2 accuracy enhancement over previous optoacoustic methods, potentially serving as a valuable tool for imaging tissue pathophysiology. PMID:27358000

  13. Oxygen saturation detection aided with the theory of lock-in amplifier

    Science.gov (United States)

    Liu, Manjin; Hui, Mei; Liu, Ming; Zhao, Yuejin; Dong, Liquan; Wu, Hong; Liu, Xiaohua; Zhao, Zhu; Feng, Yun; Chen, Di; Yang, Lei; Zhao, Jingsheng

    2014-09-01

    This paper proposes a method to recover the pulse signal with the theory of lock-in amplifier and calculates the oxygen saturation. The pulse signal is obtained based on the method of Photoplethysmography (PPG). We use a LED as the light source and a photoelectric diode as the receiver to get a measured pulse wave. Because the pulse wave obtained by this method is easily disturbed by motion artifact, we use an electrocardiogram (ECG) signal to aid PPG measurement. Firstly, the ECG signal is processed by the Fast Fourier Transform (FFT) and get the heart rate. Secondly, with the value of heart rate, a typical noise free pulse waveform can be constructed. Finally, we use it as a reference input to get a recovered pulse wave by the theory of lock-in amplifier. Thus, the value of oxygen saturation can be calculated accurately through two recovered pulse waveforms of red (660nm) and infrared (940nm) light. Some volunteers were tested. The correlation coefficient between the experimental data and the data provided by a reference instrument is 0.98, proving that this method has high reliability and utility in motion.

  14. Simultaneous high-resolution pH and spectrophotometric recordings of oxygen binding in blood microvolumes.

    Science.gov (United States)

    Oellermann, Michael; Pörtner, Hans-O; Mark, Felix C

    2014-05-01

    Oxygen equilibrium curves have been widely used to understand oxygen transport in numerous organisms. A major challenge has been to monitor oxygen binding characteristics and concomitant pH changes as they occur in vivo, in limited sample volumes. Here we report a technique allowing highly resolved and simultaneous monitoring of pH and blood pigment saturation in minute blood volumes. We equipped a gas diffusion chamber with a broad-range fibre-optic spectrophotometer and a micro-pH optode and recorded changes of pigment oxygenation along oxygen partial pressure (PO2) and pH gradients to test the setup. Oxygen binding parameters derived from measurements in only 15 μl of haemolymph from the cephalopod Octopus vulgaris showed low instrumental error (0.93%) and good agreement with published data. Broad-range spectra, each resolving 2048 data points, provided detailed insight into the complex absorbance characteristics of diverse blood types. After consideration of photobleaching and intrinsic fluorescence, pH optodes yielded accurate recordings and resolved a sigmoidal shift of 0.03 pH units in response to changing PO2 from 0 to 21 kPa. Highly resolved continuous recordings along pH gradients conformed to stepwise measurements at low rates of pH changes. In this study we showed that a diffusion chamber upgraded with a broad-range spectrophotometer and an optical pH sensor accurately characterizes oxygen binding with minimal sample consumption and manipulation. We conclude that the modified diffusion chamber is highly suitable for experimental biologists who demand high flexibility, detailed insight into oxygen binding as well as experimental and biological accuracy combined in a single setup. PMID:24436387

  15. The effects of perceiving color in living environment on QEEG, oxygen saturation, pulse rate, and emotion regulation in humans.

    Science.gov (United States)

    Sroykham, Watchara; Wongsathikun, J; Wongsawat, Y

    2014-01-01

    Light and color have been shown to have substantial physical, psychological and sociological effects on humans. Hence, an investigation on the effect of changes in light and color to the biological signals is a challenging problem. Five participants were measured the oxygen saturation (SpO2), pulse rate, and quantitative electroencephalogram (QEEG) in six colors (white, blue, green, yellow, red and black) of living environment for 5 minutes per color. Then all participants were asked to answer the emotional questionnaire of BRUMS and color performance for each color environment. The results showed brain activity of high beta wave (25-30 Hz) that associated with alertness, agitation, mental activity, and general activation of mind and body functions (at frontal lobes and temporal lobes) in red and yellow colored rooms were higher than blue, green, white and black colored rooms, respectively. It also had the relationship with the psychological effect (BRUMS). The amplitude asymmetry of beta wave (12-25 Hz) was highly attenuated in warm color (red and yellow colored rooms), moderately attenuated in cool color (green and blue colored room) and little attenuated in white and black colored rooms. The BRUMS showed that red and yellow yielded significant effect on anger (F = 4.966, p = 0.002) and confusion (F=3.853, p=0.008). Red and green color yielded high effect on vigor. Green color did not affect the depression. Blue color yielded moderate effect on confusion, tension and fatigue. White and black colors yielded low effect on any mood, but black color had no effect on vigor. In addition, we cannot observe any significant changes of pulse rate and blood oxygen saturation in each color. The results can possibly be used as the recommendation to design the room for either normal people or patients. PMID:25571419

  16. Validation of a spectroscopic sensor for the continuous, noninvasive measurement of muscle oxygen saturation and pH

    International Nuclear Information System (INIS)

    New patient monitoring technologies can noninvasively and directly provide an assessment of the adequacy of tissue perfusion through the simultaneous determination of muscle oxygen saturation (SmO2) and muscle pH (pHm). Non-pulsatile near infrared spectroscopy is used to determine these microvascular parameters. Two separate studies were conducted using an isolated perfused swine limb preparation to widely vary venous blood oxygen saturation (SviO2) and pH (pHvi) to assess the accuracy of a noninvasive sensor with the capability to simultaneously measure both parameters. The isolated limb model is necessary to establish equilibrium between the venous output of the perfusion circuit and the venule measurement of the spectroscopic sensor. The average absolute difference between SmO2 and SviO2 determined over 50 conditions of SviO2 between 13% and 83% on 3 pig limbs was 3.8% and the coefficient of determination (R2) was 0.95. The average absolute difference between pHm and pHvi determined over 69 conditions of pHvi between pHvi 6.9 and pHvi 7.5 on 3 pig limbs was 0.045 pH units with an R2 of 0.92. Measured accuracy was acceptable to support clinically relevant decision making for the assessment of impaired tissue perfusion and acidosis. Sensors were also evaluated on human subjects. There was no statistical difference in SmO2 by gender or location when multiple sensors were evaluated on the right and left calf, deltoid, and thigh of resting men and women (N = 33). SmO2 precision for subjects at rest was 5.6% over the six locations with four different sensors. (paper)

  17. Modelling cerebral blood oxygenation using Monte Carlo XYZ-PA

    Science.gov (United States)

    Zam, Azhar; Jacques, Steven L.; Alexandrov, Sergey; Li, Youzhi; Leahy, Martin J.

    2013-02-01

    Continuous monitoring of cerebral blood oxygenation is critically important for the management of many lifethreatening conditions. Non-invasive monitoring of cerebral blood oxygenation with a photoacoustic technique offers advantages over current invasive and non-invasive methods. We introduce a Monte Carlo XYZ-PA to model the energy deposition in 3D and the time-resolved pressures and velocity potential based on the energy absorbed by the biological tissue. This paper outlines the benefits of using Monte Carlo XYZ-PA for optimization of photoacoustic measurement and imaging. To the best of our knowledge this is the first fully integrated tool for photoacoustic modelling.

  18. Blood oxygen transport and metabolism of the confined lugworm Arenicola marina (L.).

    Science.gov (United States)

    Toulmond, A

    1975-12-01

    Oxygen consumption (MO2), haemoglobin oxygen saturation level (SVO2) and pH (pHv) in prebranchial blood were measured in lugworms experimentally confined in sea water at 15 degrees C. Total blood flow through the gills (Vb) was estimated. For sea water oxygen partial pressure (PwO2) between 120 and 150 Torr MO2, SVO2 and Vb were high and nearly constant. For PwO2 less than 120 Torr, Vb fell quickly, MO2 progressively dropped, and metabolism remained aerobic at the expense of the prebrancial blood oxygen store. For PwO2 less than 50 Torr, Vb and SvO2 values were extremely low, and the low pHv and the modified buffer power of the surrounding sea water showed that anaerobic metabolism was occurring. Changes in respiratory gas exchanges and metabolism during the tidal cycle are deduced from the comparison of these results with data obtained in the field. PMID:2646

  19. Regulatory Effect of Low-Intensity Optical Radiation on Oxygenation of Blood Irradiated In Vivo and Metabolic Processes

    Science.gov (United States)

    Zalesskaya, G. A.; Laskina, O. V.

    2016-03-01

    For three series of blood samples, we have studied the effect of therapeutic doses of low-intensity optical radiation (LOR) on oxygenation parameters of blood irradiated in vivo, and also on the levels of some metabolites: lactate, glucose, cholesterol. The quality of blood oxygenation was assessed using three parameters: the partial pressure of oxygen pVO2, the oxygen saturation of hemoglobin SVO2, and the oxygen level in arterial and venous blood, varying under the influence of low-intensity optical radiation due to photodissociation of hemoglobin/ligand complexes. We have established that during photohemotherapy (PHT), including extracorporeal, supravascular, and intravenous blood irradiation, positive changes occur in the oxygenation parameters and the metabolite levels, while after the courses of PHT have been completed, the individual changes in such parameters in individual patients were both positive and negative. The regulatory effect of PHT was apparent in the tendency toward a decrease in high initial values and an increase in low initial values both for the oxygenation parameters and for the metabolites; but at the doses recommended for use, PHT had a regulatory but still not a normalizing effect.

  20. C-14-activity incorporation into the protein of fetal organs of guinea pigs with different maternal placental blood flow and fetal arterial O2-saturation

    International Nuclear Information System (INIS)

    In anaesthesised gravid guinea-pigs the dilate, end section of a placental radial artery was connected to the A.carotis via a flow meter and a throttle in order to measure and widely alter the maternal placental blood flow. Blood samples are taken from the fetal A.carotis, the fetal arterial O2-saturation and the Hb-content were determined. By altering the maternal placental blood circulation the fetal arterial O2-concentration can stabilised at various levels. In order to study the protein synthesis, under these conditions one infused 185 kBq C-14-leucine over a period of 3 hours into the jugular vein of the fetus. During infusion the radioactive concentrations in whole plasma and plasma water were measured. After the infusion the radioactive concentrations in the tissue fluid, the intracellular fluid and the acid-insoluble tissue fraction (protein) of the heart, kidenys, liver, the muscles of the upper end lower part of the body, the brain and the placenta were measured. The following deductions were drawn from the findings: The maternal placental blood flow vitally influences the activity incorporation per activity concentration in the plasma water. These findings agree with the hypotheses that the maternal blood circulation has an essential influence on the fetal proteins synthesis and that this influence can be attributed to the connection between placenta connection blood flow and oxygen saturation of fetal arterial blood. (orig.)

  1. Mesoscopic organization of cobalt thin films on clean and oxygen-saturated Fe(001) surfaces

    Science.gov (United States)

    Riva, M.; Picone, A.; Giannotti, D.; Brambilla, A.; Fratesi, G.; Bussetti, G.; Duò, L.; Ciccacci, F.; Finazzi, M.

    2015-09-01

    The different morphologies of Co films grown on either the clean Fe(001) surface and the oxygen-saturated Fe(001)-p (1 ×1 ) O substrate are investigated by means of scanning tunneling microscopy, Auger electron spectroscopy, and density functional theory. The considered Co coverage range extends beyond the thickness at which layer-by-layer growth is destabilized by plastic deformations induced by the relaxation of the strain accumulated in the film. Our findings indicate that the oxygen overlayer of the Fe(001)-p (1 ×1 ) O surface floats on top of the growing Co film and strongly influences both the Co nucleation process and the film structural evolution. The layer-dependent islands nucleation of Co films grown on clean Fe(001) substrates, recently associated with a thickness-dependent adatom mobility [A. Picone et al., Phys. Rev. Lett. 113, 046102 (2014), 10.1103/PhysRevLett.113.046102], is found to be suppressed by the oxygen overlayer. The latter also significantly delays the layer-by-layer instability with respect to the oxygen-free growth. Furthermore, the body-centered-tetragonal/hexagonal-close-packed transition is not observed in the case of Co/Fe(001)-p (1 ×1 ) O sample, replaced by the development of highly ordered surface undulations. These form a mesoscopic square pattern with the sides aligned to the Fe directions, while the surface atomic structure retains the square p (1 ×1 ) symmetry in registry with the substrate. Such undulations are likely generated by a highly ordered array of interfacial misfit dislocations running along the Fe directions.

  2. Feasibility of long-term cerebral and peripheral regional tissue oxygen saturation measurements

    International Nuclear Information System (INIS)

    The aim of this study was to analyse the feasibility of long-term measurements of cerebral (crSO2) and peripheral (prSO2) regional tissue oxygen saturation on the first day of life by determining the amount of artefacts and their influence on rSO2. Near infrared spectroscopy (NIRS) measurements were performed fronto-parietal left (crSO2) and on the right forearm (prSO2). Arterial oxygen saturation (SpO2) was measured by pulse oximetry on the right wrist. Three criteria (C) were defined to identify artefacts (C1: missing values, C2: rSO2 jumping >15%, C3: rSO2 ≥ SpO2). The number of artefacts as a percentage of measurement time and mean rSO2 was calculated after the introduction of each criterion. Measurements were performed in 40 neonates. The number of artefacts in crSO2 measurements was similar after introduction of C1 (7.37 ± 4.64%) and after introduction of all criteria (8.89 ± 4.59%). The number of artefacts in prSO2 measurements after introduction of C1 was 10.83 ± 4.21%, and after introduction of all criteria significantly higher with 17.78 ± 4.27%. After introduction of C1, further criteria did not significantly change rSO2: crSO2 (78.6 ± 1.3% versus 78.5 ± 1.2%) and prSO2 (83.7 ± 0.9% versus 83.5 ± 0.9%). In conclusion, long-term NIRS measurements of crSO2 and prSO2 are feasible, since most artefacts are due to missing values and therefore easy to recognize. (paper)

  3. Blood oxygenation level-dependent MRI for assessment of renal oxygenation

    OpenAIRE

    Neugarten J; Golestaneh L

    2014-01-01

    Joel Neugarten, Ladan Golestaneh Renal Division, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA Abstract: Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI) has recently emerged as an important noninvasive technique to assess intrarenal oxygenation under physiologic and pathophysiologic conditions. Although this tool represents a major addition to our armamentarium of methodologies to investigate the role of hypoxia in the pathogenesis of acute...

  4. Effects of nebulized terbutaline on oxygen saturation in acute asthmatic children.

    Science.gov (United States)

    Lin, Y Z; Hsieh, K H; Shih, T Y; Chen, W; Wu, K W

    1994-01-01

    To evaluate the paradoxical effect of oxygen desaturation following beta-2 bronchodilator nebulization treatment in acute asthmatic children, a total of 47 patients, aged between 1.8 and 14 years, 27 males and 20 females, were studied. Twenty ml of nebulized normal saline (NS), followed by 10 mg (4 ml) of terbutaline sulphate solution (TSS) in 20 ml NS, were delivered by an ultrasonic nebulizer in 10 min to each patient through a connecting air tube placed in front of the nose and mouth. Oxygen saturation (SaO2) and pulse rate were monitored, using a pulse oximeter, before study and every two minutes until the end of the study. The clinical severity score and peak expiratory flow rate (PEFR) were checked before the study, at the end of inhalation of NS, and at the end of inhalation of TSS. SaO2 was increased both after nebulized NS and TSS when compared with the pre-study data (p 0.9). No SaO2 decrease after nebulized TSS was observed in any of the seven severe asthmatic children with a prestudy SaO2 < or = 90%. The clinical severity score and PEFR were also significantly improved both after nebulized NS and TSS (p < 0.0001 and p < 0.001, respectively for NS, and both p < 0.0001 for TSS).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7942023

  5. Hypoxia effects on gill surface area and blood oxygen-carrying capacity of the Atlantic stingray, Dasyatis sabina.

    Science.gov (United States)

    Dabruzzi, Theresa F; Bennett, Wayne A

    2014-08-01

    Atlantic stingrays, Dasyatis sabina, are common residents of shallow-water seagrass habitats that experience natural cycles of severe hypoxia during summer months. We hypothesized that stingrays exposed to hypoxic episodes would improve their hypoxia tolerance by increasing branchial surface area and altering blood oxygen-carrying capacity. To this end, we compared critical oxygen minimum, gill morphology, and hemoglobin/hematocrit levels in a control group of Atlantic stingrays held at continuous oxygen saturations of 80-90% (≥5.5 mg/l), to treatment groups exposed to a 7-h hypoxic interval at 55% (~4.0 mg/l), or 30% oxygen saturation (~2.0 mg/l). Stingrays in hypoxic treatment groups significantly improved their hypoxia tolerance. Critical oxygen minimum values fell from 0.7 ± 0.11 mg/l in control fish to 0.4 ± 0.05 and 0.4 ± 0.06 mg/l in the 55 and 30% saturation treatment groups, respectively. Mass-specific gill surface area between control fish and the 30% saturation treatment group increased by 1.7-fold, from 85 to 142 mm(2)/g. Although stingrays did not show an increase in hematocrit or hemoglobin levels, production of more efficient hemoglobin isoforms could not be ruled out. An increase in hypoxia tolerance allows Atlantic stingrays to forage for longer times and across a wide range of hypoxic habitats that are less accessible to predators and competitors. PMID:24352883

  6. Regional cerebral oxygen saturation in newborn infants in the first 15 min of life after vaginal delivery

    International Nuclear Information System (INIS)

    The objective of this study was to evaluate regional oxygen saturation of the brain during immediate transition after birth, and to correlate it with pre-ductal arterial oxygen saturation in newborn infants. The prospective observational study including newborn infants in the first 15 min after spontaneous vaginal delivery and uncomplicated transitional period was undertaken. Regional cerebral oxygen saturation (rSO2brain) was measured using near-infrared spectroscopy. Arterial oxygen saturation (SpO2) and heart rate (HR) were measured on the right wrist by pulse oximetry. rSO2brain, SpO2 and HR measurements were started immediately after birth and were performed in the first 15 min of life. Cerebral fractional tissue oxygen extraction (FTOE) was calculated for each minute. Of 145 newborn infants, 16 were included and the gender allocation was 31 females (49.2%) and 32 males (50.8%). rSO2brain increased rapidly from 39% (2 min) to 69% (5 min), SpO2 increased from 72% (2 min) to 96% (14 min) and FTOE showed a significant decrease from minute 2 (0.47) until minute 4 (0.30) and an increase between 8 to 13 min. rSO2brain increased rapidly after vaginal delivery. Although SpO2 increased within the first 14 min after delivery, rSO2brain showed no further significant changes after 5 min. FTOE decreased in the first 4 min and reached standard values subsequently. (paper)

  7. Eigenspectra optoacoustic tomography achieves quantitative blood oxygenation imaging deep in tissues

    CERN Document Server

    Tzoumas, Stratis; Olefir, Ivan; Stangl, Stefan; Symvoulidis, Panagiotis; Glasl, Sarah; Bayer, Christine; Multhoff, Gabriele; Ntziachristos, Vasilis

    2015-01-01

    Light propagating in tissue attains a spectrum that varies with location due to wavelength-dependent fluence attenuation by tissue optical properties, an effect that causes spectral corruption. Predictions of the spectral variations of light fluence in tissue are challenging since the spatial distribution of optical properties in tissue cannot be resolved in high resolution or with high accuracy by current methods. Spectral corruption has fundamentally limited the quantification accuracy of optical and optoacoustic methods and impeded the long sought-after goal of imaging blood oxygen saturation (sO2) deep in tissues; a critical but still unattainable target for the assessment of oxygenation in physiological processes and disease. We discover a new principle underlying light fluence in tissues, which describes the wavelength dependence of light fluence as an affine function of a few reference base spectra, independently of the specific distribution of tissue optical properties. This finding enables the introd...

  8. TRPV4 inhibition counteracts edema and inflammation and improves pulmonary function and oxygen saturation in chemically induced acute lung injury.

    Science.gov (United States)

    Balakrishna, Shrilatha; Song, Weifeng; Achanta, Satyanarayana; Doran, Stephen F; Liu, Boyi; Kaelberer, Melanie M; Yu, Zhihong; Sui, Aiwei; Cheung, Mui; Leishman, Emma; Eidam, Hilary S; Ye, Guosen; Willette, Robert N; Thorneloe, Kevin S; Bradshaw, Heather B; Matalon, Sadis; Jordt, Sven-Eric

    2014-07-15

    The treatment of acute lung injury caused by exposure to reactive chemicals remains challenging because of the lack of mechanism-based therapeutic approaches. Recent studies have shown that transient receptor potential vanilloid 4 (TRPV4), an ion channel expressed in pulmonary tissues, is a crucial mediator of pressure-induced damage associated with ventilator-induced lung injury, heart failure, and infarction. Here, we examined the effects of two novel TRPV4 inhibitors in mice exposed to hydrochloric acid, mimicking acid exposure and acid aspiration injury, and to chlorine gas, a severe chemical threat with frequent exposures in domestic and occupational environments and in transportation accidents. Postexposure treatment with a TRPV4 inhibitor suppressed acid-induced pulmonary inflammation by diminishing neutrophils, macrophages, and associated chemokines and cytokines, while improving tissue pathology. These effects were recapitulated in TRPV4-deficient mice. TRPV4 inhibitors had similar anti-inflammatory effects in chlorine-exposed mice and inhibited vascular leakage, airway hyperreactivity, and increase in elastance, while improving blood oxygen saturation. In both models of lung injury we detected increased concentrations of N-acylamides, a class of endogenous TRP channel agonists. Taken together, we demonstrate that TRPV4 inhibitors are potent and efficacious countermeasures against severe chemical exposures, acting against exaggerated inflammatory responses, and protecting tissue barriers and cardiovascular function. PMID:24838754

  9. Deoxygenation Reduces Sickle Cell Blood Flow at Arterial Oxygen Tension.

    Science.gov (United States)

    Lu, Xinran; Wood, David K; Higgins, John M

    2016-06-21

    The majority of morbidity and mortality in sickle cell disease is caused by vaso-occlusion: circulatory obstruction leading to tissue ischemia and infarction. The consequences of vaso-occlusion are seen clinically throughout the vascular tree, from the relatively high-oxygen and high-velocity cerebral arteries to the relatively low-oxygen and low-velocity postcapillary venules. Prevailing models of vaso-occlusion propose mechanisms that are relevant only to regions of low oxygen and low velocity, leaving a wide gap in our understanding of the most important pathologic process in sickle cell disease. Progress toward understanding vaso-occlusion is further challenged by the complexity of the multiple processes thought to be involved, including, but not limited to 1) deoxygenation-dependent hemoglobin polymerization leading to impaired rheology, 2) endothelial and leukocyte activation, and 3) altered cellular adhesion. Here, we chose to focus exclusively on deoxygenation-dependent rheologic processes in an effort to quantify their contribution independent of the other processes that are likely involved in vivo. We take advantage of an experimental system that, to our knowledge, uniquely enables the study of pressure-driven blood flow in physiologic-sized tubes at physiologic hematocrit under controlled oxygenation conditions, while excluding the effects of endothelium, leukocyte activation, adhesion, inflammation, and coagulation. We find that deoxygenation-dependent rheologic processes are sufficient to increase apparent viscosity significantly, slowing blood flow velocity at arterial oxygen tension even without additional contributions from inflammation, adhesion, and endothelial and leukocyte activation. We quantify the changes in apparent viscosity and define a set of functional regimes of sickle cell blood flow personalized for each patient that may be important in further dissecting mechanisms of in vivo vaso-occlusion as well as in assessing risk of patient

  10. The estimation of recovery time of calf muscle oxygen saturation during exercise by using functional near infrared spectroscopy

    Science.gov (United States)

    Ansari, M. A.; Shojaeifar, M.; Mohajerani, E.

    2014-08-01

    Several methods of near infrared spectroscopy such as functional near infrared spectroscopy (fNIRS) and pulse oximetry have been applied for monitoring of tissue oxygenation or arterial oxygen saturation. Some vascular diseases can be diagnosed through measurements of tissue oxygenation. In this study, the temporal variation of oxygenation of calf muscle after exercise is studied by fNIRS. First, the accuracy of a low-cost fNIRS system is studied by measuring the oxygenation of a lipid phantom. Moreover, in-vivo study is performed to evaluate the precision of this system. Then, the variation of muscle oxygenation of four persons during exercise is measured and also the recovery time after walking/running is measured by this fNIRS system.

  11. Wavelength-modulated differential photoacoustic radar imager (WM-DPARI): accurate monitoring of absolute hemoglobin oxygen saturation

    Science.gov (United States)

    Choi, Sung Soo Sean; Lashkari, Bahman; Dovlo, Edem; Mandelis, Andreas

    2016-01-01

    Accurate monitoring of blood oxy-saturation level (SO2) in human breast tissues is clinically important for predicting and evaluating possible tumor growth at the site. In this work, four different non-invasive frequency-domain photoacoustic (PA) imaging modalities were compared for their absolute SO2 characterization capability using an in-vitro sheep blood circulation system. Among different PA modes, a new WM-DPAR imaging modality could estimate the SO2 with great accuracy when compared to a commercial blood gas analyzer. The developed WM-DPARI theory was further validated by constructing SO2 tomographic images of a blood-containing plastisol phantom.

  12. Blood oxygen binding properties for the burrowing owl, Athene cunicularia.

    Science.gov (United States)

    Maginniss, L A; Kilgore, D L

    1989-05-01

    Isocapnic O2 equilibrium curves (O2ECs) were generated for whole blood of 4 adult burrowing owls (Athene cunicularia) using thin film techniques. At in vivo pHa (7.49 +/- 0.02; mean +/- 1 SEM) and 41 degrees C, the PO2 at half saturation (P50) was 42.3 +/- 0.8 Torr. CO2 and fixed acid (H+) Bohr slopes (delta log P50/delta pH) were -0.46 +/- 0.01 and -0.42 +/- 0.02, respectively, demonstrating a small specific CO2 effect. CO2 and H+ Bohr slopes were saturation-independent between 0.1 and 0.9 S. Hill plots for Athene blood were non-linear; the Hill coefficient (n) increased from 2.6 below 0.4 S to 3.4 above 0.6 S. Owl equilibrium data were accurately described by the equation: S = [(7.7 x 10(6]/(P4 + 44P3 - 108P2 + 3.5 x 10(4)P) + 1]-1. This complex O2EC shape may result from Hb heterogeneity; isoelectric focusing showed 4 isoHbs with a molar ratio of 9:1:1:1. This study revealed no apparent adaptations of Athene blood for hypoxic and hypercapnic conditions. We conclude that the observed blood O2 binding properties promote tissue O2 delivery during periods of surface activity. While occupying its burrow, the owl compensates for moderate alterations in inspired gas composition partly through increased ventilation. PMID:2749025

  13. Changes in human muscle oxygen saturation and mean fiber conduction velocity during intense dynamic exercise - effect of muscular training status

    DEFF Research Database (Denmark)

    Kilen, Anders; Gizzi, Leonardo; Jensen, Bente Rona;

    2012-01-01

    Introduction: In this study we investigated whether an association exists between muscle fiber conduction velocity (MFCV) and local muscle oxygen saturation (StO(2) ) in the superficial part of the latissimus dorsi muscle of runners and swimmers during exhaustive dynamic exercise. Methods: Partic...

  14. Higher Rates of Retinopathy of Prematurity after Increasing Oxygen Saturation Targets for Very Preterm Infants: Experience in a Single Center.

    Science.gov (United States)

    Manley, Brett J; Kuschel, Carl A; Elder, James E; Doyle, Lex W; Davis, Peter G

    2016-01-01

    Randomized trials of oxygen saturation target ranges for extremely preterm infants showed increased survival but increased retinopathy of prematurity with higher compared with lower target ranges. In our center, changing from a target range of 88%-92% to 91%-95% has been associated with increased rates and severity of retinopathy of prematurity. PMID:26548746

  15. Blood oxygen flux estimation with a combined photoacoustic and high-frequency ultrasound microscopy system: a phantom study

    Science.gov (United States)

    Jiang, Yan; Forbrich, Alex; Harrison, Tyler; Zemp, Roger J.

    2012-03-01

    The metabolic rate of oxygen consumption, an important indicator of tissue metabolism, can be expressed as the change of net blood oxygen flux into and out of a tissue region per 100 g of tissue. In this work, we propose a photoacoustic and Doppler ultrasound method for imaging local blood oxygen flux of a single vessel. An imaging system for combined photoacoustic and high-frequency ultrasound microscopy is presented. This system uses a swept-scan 25-MHz ultrasound transducer with confocal dark-field laser illumination optics. A pulse-sequencer enables ultrasonic and laser pulses to be interlaced so that photoacoustic and Doppler ultrasound images are co-registered. Since the mean flow speed can be measured by color Doppler ultrasound, the vessel cross-sectional area can be measured by power Doppler or structural photoacoustic imaging, and multi-wavelength photoacoustic methods can be used to estimate oxygen saturation (sO2) and total concentration of haemoglobin (CHb), all of the parameters necessary for oxygen flux estimation can be provided. The accuracy of the flow speed and sO2 estimation has been investigated. In vitro sheep blood phantom experiments have been performed at different sO2 levels and mean flow speeds. Blood oxygen flux has been estimated, and the uncertainty of the measurement has been quantified.

  16. Influence of dissolved oxygen on silver nanoparticle mobility and dissolution in water-saturated quartz sand

    Energy Technology Data Exchange (ETDEWEB)

    Mittelman, Anjuliee M.; Taghavy, Amir; Wang, Yonggang; Abriola, Linda M.; Pennell, Kurt D., E-mail: kurt.pennell@tufts.edu [Tufts University, Department of Civil and Environmental Engineering (United States)

    2013-07-15

    The influence of dissolved oxygen (DO) on the transport behavior and dissolution kinetics of silver nanoparticles (nAg) was explored through a combination of experimental and mathematical modeling studies. One-dimensional column experiments were conducted with water-saturated 40-50 mesh Ottawa sand, operated at pH 4 or 7 under three DO conditions (8.9, 2, or <0.2 mg/L). The experimental protocol consisted of a nAg deposition phase, designed to assess nanoparticle mobility as a function of DO level, followed by a dissolution phase, to evaluate the release of Ag{sup +} from retained nanoparticles. Experimental observations revealed that the mobility of nAg increased by 15 % when the DO level was reduced from 8.9 to <0.2 mg/L at pH 4, and that, once retained by the quartz sand, the fraction of nAg mass eluted as Ag{sup +} decreased from 21.6 to 13.5 to 11.3 % with decreasing oxygen level (8.9, 2, and <0.2 mg/L, respectively). In both batch and column studies, rates of nAg dissolution decreased over time, behavior attributed to aging of the nanoparticle surface due to oxidation. A hybrid Eulerian-Lagrangian nanoparticle transport model was developed and implemented to simulate the mobility of nAg, subject to DO-dependent dissolution kinetics and particle aging. Model simulations accurately captured nAg transport and dissolution as a function of pH and DO level, and demonstrate the importance of considering nanoparticle surface aging to accurately predict Ag{sup +} release over time.

  17. Blood flow mechanics and oxygen transport and delivery in the retinal microcirculation: multiscale mathematical modeling and numerical simulation.

    Science.gov (United States)

    Causin, Paola; Guidoboni, Giovanna; Malgaroli, Francesca; Sacco, Riccardo; Harris, Alon

    2016-06-01

    The scientific community continues to accrue evidence that blood flow alterations and ischemic conditions in the retina play an important role in the pathogenesis of ocular diseases. Many factors influence retinal hemodynamics and tissue oxygenation, including blood pressure, blood rheology, oxygen arterial permeability and tissue metabolic demand. Since the influence of these factors on the retinal circulation is difficult to isolate in vivo, we propose here a novel mathematical and computational model describing the coupling between blood flow mechanics and oxygen ([Formula: see text]) transport in the retina. Albeit in a simplified manner, the model accounts for the three-dimensional anatomical structure of the retina, consisting in a layered tissue nourished by an arteriolar/venular network laying on the surface proximal to the vitreous. Capillary plexi, originating from terminal arterioles and converging into smaller venules, are embedded in two distinct tissue layers. Arteriolar and venular networks are represented by fractal trees, whereas capillary plexi are represented using a simplified lumped description. In the model, [Formula: see text] is transported along the vasculature and delivered to the tissue at a rate that depends on the metabolic demand of the various tissue layers. First, the model is validated against available experimental results to identify baseline conditions. Then, a sensitivity analysis is performed to quantify the influence of blood pressure, blood rheology, oxygen arterial permeability and tissue oxygen demand on the [Formula: see text] distribution within the blood vessels and in the tissue. This analysis shows that: (1) systemic arterial blood pressure has a strong influence on the [Formula: see text] profiles in both blood and tissue; (2) plasma viscosity and metabolic consumption rates have a strong influence on the [Formula: see text] tension at the level of the retinal ganglion cells; and (3) arterial [Formula: see text

  18. Oxygen tension measurement using an automatic blood gas analyser.

    Science.gov (United States)

    Becket, J; Orchard, C; Chakrabarti, M K; Hall, G M; Gillies, I D; Bourdillon, P J

    1981-08-01

    Two different methods of assessing the reliability of the oxygen electrode of one model of an automatic blood gas analyser (BGA) have been studied. In the first, a single automatic BGA was assessed by using outdated bank blood which was pumped around a small extracorporeal circuit into which known gas mixtures were passed. Oxygen tension was varied between 2 and 16 kPa. In the second, fresh heparinized blood was tonometered with calibrated gases and submitted to the automatic BGA used in the first part of the study and also to three other identical machines. Each of the machines was between 3 and 4 years old.Eighteen different units of blood were used in the first part of the study. The correlation coefficient between the automatic BGA and the Po(2) in the extracorporeal circuit varied between 0.29 and 0.99. 31% of the total of 209 measurements made by the automatic BGA were more than 1.2 kPa from the reference value, 25% of them being between 1.2 and 4.0 kPa from the reference value. In the second part of the study, the correlation coefficient between this automatic BGA and the tonometered blood was 0.96. The correlation coefficients for the 3 other identical BGAs were 0.84, 0.97 and 0.88, indicating that the BGA used in the first part of the study was no worse than any of the others.It is suggested that although clinicians are likely to ignore readings of an automatic BGA that are more than 4.0 kPa from the true value and are likely to repeat the investigation, readings between 1.2 and 4.0 kPa from the true value may adversely affect patient management. PMID:7288796

  19. Effect of Pressure, Water Depth and Water Flow Rate on Oxygen Saturation Level in Activated Sludge Process

    Directory of Open Access Journals (Sweden)

    Nabil N. Atta

    2011-01-01

    Full Text Available Problem statement: The role of aeration in activated sludge process is to provide oxygen to microorganisms as they assimilate the organic carbon compounds and digest a portion of them to carbon dioxide and water, sulfate and nitrate compounds. The water aeration equipment used in this process consumes as much as 60-80% of total power requirements in modern wastewater treatment plants. Approach: The objective of this study is to enhance the oxygen transfer in aeration tank in activated sludge process by increasing pressure inside the part of aeration tank to increase the saturation level of dissolved oxygen in wastewater. The diffuser cap model is the experimental model which was used to show the effect of increasing pressure on oxygen transfer level. Three cases were considered, the first used without diffuser cap, the second with diffuser cap and the third with diffuser cap and plastic strips. Results: Obtained results show that in case of using the model with diffuser cap enhanced the oxygen level by about 5% than in case of without diffuser cap while that of adding plastic strips enhanced the oxygen level by about 7%. The variation of water flow showed that increasing water flow rate from 1-2 L min-1 decreased the oxygen saturation level by about 6%. Furthermore, increasing water depth from 15-60 cm increased the oxygen level by about 40%. Conclusion: The diffuser cap model showed that the increase of pressure and water depth increased the dissolved oxygen level while increasing water flow rate decreased the dissolved oxygen level.

  20. Cerebral blood flow and oxygen metabolism in the Rett syndrome

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) was performed on six patients with the Rett syndrome and the results were compared with the concurrent clinical status of the patients. The cerebral metabolic rate of oxygen (CMRO2) was low in five patients, and oxygen extraction fraction (OEF) was low in four patients; both had a tendency to decline with advancing age. Although the cause is unknown, it is suggested that impaired oxidative metabolism exists in the Rett syndrome. An analysis of the distribution among brain regions showed that the ratios of values for the frontal cortex to those for the temporal cortex for both the cerebral blood flow (CBF) and CMRO2 were lower than those for the controls, which may indicate the loss of of hyperfrontality in the Rett syndrome. Distribution of brain metabolism may be immature in the Rett syndrome. (author)

  1. Cerebral blood flow and oxygen metabolism in the Rett syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Hideto; Fueki, Noboru; Suzuki, Hisaharu; Sakuragawa, Norio; Iio, Masaaki (National Central Hospital for Mental, Nervous and Muscular Disorders, Tokyo (Japan))

    1992-05-01

    Positron emission tomography (PET) was performed on six patients with the Rett syndrome and the results were compared with the concurrent clinical status of the patients. The cerebral metabolic rate of oxygen (CMRO{sub 2}) was low in five patients, and oxygen extraction fraction (OEF) was low in four patients; both had a tendency to decline with advancing age. Although the cause is unknown, it is suggested that impaired oxidative metabolism exists in the Rett syndrome. An analysis of the distribution among brain regions showed that the ratios of values for the frontal cortex to those for the temporal cortex for both the cerebral blood flow (CBF) and CMRO{sub 2} were lower than those for the controls, which may indicate the loss of of hyperfrontality in the Rett syndrome. Distribution of brain metabolism may be immature in the Rett syndrome. (author).

  2. Cerebral blood flow and oxygen metabolism in ischemic cerebrovascular disease

    International Nuclear Information System (INIS)

    Using positron emission tomography and 15O-steady state method, cerebral blood flow (CBF), oxygen consumption and oxygen extraction fraction were measured in patients with embolic occlusion and in those with thrombotic occlusion in the carotid system. By the study of patients with embolic occlusion, we evaluated ischemic threshold of CBF for infarction to be 16 ml/100 ml/min. The area of 'penumbra' could be estimated in regions with CBF value just above this threshold. In the patients with thrombotic occlusive lesion, we clarified that the efficiency of the collateral circulation was mainly related to the grade of peripheral atherosclerosis. These findings must be helpful to develop better strategy for treatment of cerebral ischemic disease. (author)

  3. Effects of salmeterol on sleeping oxygen saturation in chronic obstructive pulmonary disease.

    LENUS (Irish Health Repository)

    Ryan, Silke

    2012-02-01

    BACKGROUND: Sleep is associated with important adverse effects in patients with chronic obstructive pulmonary disease (COPD), such as disturbed sleep quality and gas exchange, including hypoxemia and hypercapnia. The effects of inhaled long-acting beta(2)-agonist therapy (LABA) on these disturbances are unclear. OBJECTIVES: The aim of the study was to assess the effect of inhaled salmeterol on nocturnal sleeping arterial oxygen saturation (SaO(2)) and sleep quality. METHODS: In a randomized, double-blind, placebo-controlled, crossover study of moderate\\/severe stable COPD patients, we compared the effects of 4 weeks of treatment with salmeterol 50 microg b.d. and matching placebo on sleeping SaO(2) and sleep quality. Overnight polysomnography (PSG) was performed at baseline, and after 4 and 8 weeks in addition to detailed pulmonary function testing. Of 15 patients included, 12 completed the trial (median age 69 years, forced expiratory volume in 1 s, FEV(1): 39%). RESULTS: Both mean SaO(2) [salmeterol vs. placebo: 92.9% (91.2, 94.7) vs. 91.0% (88.9, 94.8); p = 0.016] and the percentage of sleep spent below 90% of SaO(2) [1.8% (0.0, 10.8) vs. 25.6% (0.5, 53.5); p = 0.005] improved significantly with salmeterol. Sleep quality was similar with both salmeterol and placebo on PSG. Static lung volumes, particularly trapped gas volume, tended to improve with salmeterol. CONCLUSION: We conclude that inhaled LABA therapy improves sleeping SaO(2) without significant change in sleep quality.

  4. Hepatic ischemia-reperfusion syndrome after partial liver resection (LR): hepatic venous oxygen saturation, enzyme pattern, reduced and oxidized glutathione, procalcitonin and interleukin-6.

    Science.gov (United States)

    Kretzschmar, Michael; Krüger, Antie; Schirrmeister, Wulf

    2003-06-01

    The hepatic ischemia-reperfusion syndrome was investigated in 28 patients undergoing elective partial liver resection with intraoperative occlusion of hepatic inflow (Pringle maneuver) using the technique of liver vein catheterization. Hepatic venous oxygen saturation (ShvO2) was monitored continuously up to 24 hours after surgery. Aspartate aminotransferase, glutamate dehydrogenase, gamma-glutamyl transpeptidase, pseudocholinesterase, alpha-glutathione S-transferase, reduced and oxidized glutathione, procalcitonine, and interleukin-6 were serially measured both before and after Pringle maneuver during the resection and postoperatively in arterial and/or hepatic venous blood. ShvO2 measurement demonstrated that peri- and postoperative management was suitable to maintain an optimal hepatic oxygen supply. As expected, we were able to demonstrate a typical enzyme pattern of postischemic liver injury. There was a distinct decrease of reduced glutathione levels both in arterial and hepatic venous plasma after LR accompanied by a strong increase in oxidized glutathione concentration during the phase of reperfusion. We observed increases in procalcitonin and interleukin-6 levels both in arterial and hepatic venous blood after declamping. Our data support the view that liver resection in man under conditions of inflow occlusion resulted in ischemic lesion of the liver (loss of glutathione synthesizing capacity with disturbance of protection against oxidative stress) and an additional impairment during reperfusion (liberation of reactive oxygen species, local and systemic inflammation reaction with cytokine production). Additionally, we found some evidence for the assumption that the liver has an export function for reduced glutathione into plasma in man. PMID:12877355

  5. The effects of different ventilator modes on cerebral tissue oxygen saturation in patients with bidirectional superior cavopulmonary connection

    Directory of Open Access Journals (Sweden)

    Ayda Türköz

    2014-01-01

    Full Text Available Aims and Objectives: We used near-infrared spectroscopy to document changes in cerebral tissue oxygen saturation (SctO 2 in response to ventilation mode alterations after bidirectional Glenn (BDG; superior cavopulmonary connection procedure. We also determined whether spontaneous ventilation have a beneficial effect on hemodynamic status, lactate and SctO 2 when compared with other ventilation modes. Materials and Methods: 20 consecutive patients undergoing BDG were included. We measured SctO 2 during three ventilator modes (intermittent positive-pressure ventilation [IPPV]; synchronized intermittent mandatory ventilation [SIMV]; and continuous positive airway pressure + pressure support ventilation [CPAP + PSV]. We, also, measured mean airway pressure (AWP, arterial blood gases, lactate and systolic arterial pressures (SAP. Results: There was no change in SctO 2 in IPPV and SIMV modes; the SctO 2 measured during CPAP + PSV and after extubation increased significantly (60.5 ± 11, 61 ± 10, 65 ± 10, 66 ± 11 respectively ( P < 0.05. The differences in the SAP measured during IPPV and SIMV modes was insignificant; the SAP increased significantly during CPAP + PSV mode and after extubation compared with IPPV and SIMV (109 ± 11, 110 ± 12, 95 ± 17, 99 ± 13 mmHg, respectively ( P < 0.05. Mean AWP did not change during IPPV and SIMV modes, mean AWP decreased significantly during CPAP + PSV mode (14 ± 4, 14 ± 3, 10 ± 1 mmHg, respectively ( P < 0.01. Conclusions: The SctO 2 was higher during CPAP + PSV ventilation and after extubation compared to IPPV and SIMV modes of ventilation. The mean AWP was lower during CPAP + PSV ventilation compared to IPPV and SIMV modes of ventilation.

  6. Influence of blood donation on oxygen uptake kinetics during moderate and heavy intensity cycle exercise.

    Science.gov (United States)

    Gordon, D; Marshall, K; Connell, A; Barnes, R J

    2010-05-01

    The purpose of this study was to determine the effects of a reduced whole body blood volume on the kinetic response of VO(2) during moderate and heavy intensity exercise. Six males and four females (age, 21+/-2 yrs; height, 175.2+/-5.1 cm; weight, 66.4+/-2.8 kg; VO(2)max, 53.0+/-4.1 ml x kg (-1) x min(-1)), completed a square-wave cycling ramp test to determine ventilatory threshold (VT) and VO(2max). Kinetics trials were completed 24 h pre and post donation of 450 cm (3) of blood. The kinetics trials were moderate intensity (80%VT) and heavy intensity (Delta50% VT - VO(2max)). Breath-by-breath gas exchange, heart rate, blood pressure, haemoglobin O(2) saturation, and blood [lactate] were measured throughout the trials. Post-donation haemoglobin, haematocrit and erythrocyte count were all significantly reduced (pexercise (p>or= 0.05), or in the amplitude of the slow component. The capacity of the cardiovascular system to meet the metabolic demands of skeletal muscle at the onset of exercise does not limit the oxygen uptake. PMID:20180178

  7. Measurement of forearm oxygen consumption

    DEFF Research Database (Denmark)

    Astrup, A; Simonsen, L; Bülow, J;

    1988-01-01

    blood flow and decreases skeletal muscle blood flow. This facilitates mixing of superficial blood with deep venous blood. Contralateral heating increased deep venous oxygen saturation and abolished the pronounced glucose-induced increase in oxygen consumption observed in the control experiments after...

  8. The relationship between cerebral oxygen saturation changes and post operative neurologic complications in patients undergoing cardiac surgery

    International Nuclear Information System (INIS)

    To study the relationship between cerebral oxygen saturation changes and postoperative neurologic complications. Seventy two adult patients with ASA class II, III who were scheduled for elective cardiac surgery, were randomized into three groups: Group I: with CPB (on -pump) Group II: without CPB (off- pump) Group III: valve surgery. Neuropsychological outcome was assessed by the Mini-Mental State Examination (MMSE). Cerebral oxygen saturation was also measured. There was no statistical difference in desaturation of more than 20% among three groups (P=0.113) but it was significant between group I and II (P=0.042). Changes of rSo/sub 2/ in different hours of surgery was significant in group I and group II (P=0.0001 in both) but it was not significant in group III ( P=0.075) . Although cerebral oximetry is a noninvasive and useful method of monitoring during cardiac surgery, it has low accuracy to determine postoperative neurologic complications. (author)

  9. Interpreting hemoglobin and water concentration, oxygen saturation, and scattering measured in vivo by near-infrared breast tomography

    OpenAIRE

    Srinivasan, Subhadra; Pogue, Brian W.; Jiang, Shudong; Dehghani, Hamid; de Kogel, Christine; Soho, Sandra; Gibson, Jennifer J.; Tosteson, Tor D.; Poplack, Steven P.; Paulsen, Keith D.

    2003-01-01

    Near-infrared spectroscopic tomography was used to measure the properties of 24 mammographically normal breasts to quantify whole-breast absorption and scattering spectra and to evaluate which tissue composition characteristics can be determined from these spectra. The absorption spectrum of breast tissue allows quantification of (i) total hemoglobin concentration, (ii) hemoglobin oxygen saturation, and (iii) water concentration, whereas the scattering spectrum provides information about the ...

  10. Design a Wearable Device for Blood Oxygen Concentration and Temporal Heart Beat Rate

    Science.gov (United States)

    Myint, Cho Zin; Barsoum, Nader; Ing, Wong Kiing

    2010-06-01

    The wireless network technology is increasingly important in healthcare as a result of the aging population and the tendency to acquire chronic disease such as heart attack, high blood pressure amongst the elderly. A wireless sensor network system that has the capability to monitor physiological sign such as SpO2 (Saturation of Arterial Oxygen) and heart beat rate in real-time from the human's body is highlighted in this study. This research is to design a prototype sensor network hardware, which consists of microcontroller PIC18F series and transceiver unit. The sensor is corporate into a wearable body sensor network which is small in size and easy to use. The sensor allows a non invasive, real time method to provide information regarding the health of the body. This enables a more efficient and economical means for managing the health care of the population.

  11. Measurement of changes in blood oxygenation using Multispectral Optoacoustic Tomography (MSOT) allows assessment of tumor development

    Science.gov (United States)

    Tomaszewski, Michal R.; Quiros-Gonzalez, Isabel; Joseph, James; Bohndiek, Sarah E.

    2016-03-01

    The ability to evaluate tumor oxygenation in the clinic could indicate prognosis and enable treatment monitoring, since oxygen deficient cancer cells are more resistant to chemotherapy and radiotherapy. MultiSpectral Optoacoustic Tomography (MSOT) is a hybrid technique combining the high contrast of optical imaging with the spatial resolution and penetration depth similar to ultrasound. We aim to demonstrate that MSOT can be used to monitor the development of tumor vasculature. To establish the relationship between MSOT derived imaging biomarkers and biological changes during tumor development, we performed MSOT on nude mice (n=10) bearing subcutaneous xenograft U87 glioblastoma tumors using a small animal optoacoustic tomography system. The mice were maintained under inhalation anesthesia during imaging and respired oxygen content was modified between 21% and 100%. The measurements from early (week 4) and late (week 7) stages of tumor development were compared. To further explore the functionality of the blood vessels, we examined the evolution of changes in the abundance of oxy- and deoxyhemoglobin in the tumors in response to a gas challenge. We found that the kinetics of the change in oxygen saturation (SO2) were significantly different between small tumors and the healthy blood vessels in nearby normal tissue (p=0.0054). Furthermore, we showed that there was a significant difference in the kinetics of the gas challenge between small and large tumors (p=0.0015). We also found that the tumor SO2 was significantly correlated (p=0.0057) with the tumor necrotic fraction as assessed by H&E staining in histology. In the future, this approach may be of use in the clinic as a method for tumor staging and assessment of treatment response.

  12. Iron- and indium-catalyzed reactions toward nitrogen- and oxygen-containing saturated heterocycles.

    Science.gov (United States)

    Cornil, Johan; Gonnard, Laurine; Bensoussan, Charlélie; Serra-Muns, Anna; Gnamm, Christian; Commandeur, Claude; Commandeur, Malgorzata; Reymond, Sébastien; Guérinot, Amandine; Cossy, Janine

    2015-03-17

    A myriad of natural and/or biologically active products include nitrogen- and oxygen-containing saturated heterocycles, which are thus considered as attractive scaffolds in the drug discovery process. As a consequence, a wide range of reactions has been developed for the construction of these frameworks, much effort being specially devoted to the formation of substituted tetrahydropyrans and piperidines. Among the existing methods to form these heterocycles, the metal-catalyzed heterocyclization of amino- or hydroxy-allylic alcohol derivatives has emerged as a powerful and stereoselective strategy that is particularly interesting in terms of both atom-economy and ecocompatibility. For a long time, palladium catalysts have widely dominated this area either in Tsuji-Trost reactions [Pd(0)] or in an electrophilic activation process [Pd(II)]. More recently, gold-catalyzed formation of saturated N- and O-heterocycles has received growing attention because it generally exhibits high efficiency and diastereoselectivity. Despite their demonstrated utility, Pd- and Au-complexes suffer from high costs, toxicity, and limited natural abundance, which can be barriers to their widespread use in industrial processes. Thus, the replacement of precious metals with less expensive and more environmentally benign catalysts has become a challenging issue for organic chemists. In 2010, our group took advantage of the ability of the low-toxicity and inexpensive FeCl3 in activating allylic or benzylic alcohols to develop iron-catalyzed N- and O-heterocylizations. We first focused on N-heterocycles, and a variety of 2,6-disubstituted piperidines as well as pyrrolidines were synthesized in a highly diastereoselective fashion in favor of the cis-compounds. The reaction was further extended to the construction of substituted tetrahydropyrans. Besides triggering the formation of heterocycles, the iron salts were shown to induce a thermodynamic epimerization, which is the key to reach the high

  13. The human ear canal: investigation of its suitability for monitoring photoplethysmographs and arterial oxygen saturation

    International Nuclear Information System (INIS)

    For the last two decades, pulse oximetry has been used as a standard procedure for monitoring arterial oxygen saturation (SpO2). However, SpO2 measurements made from extremities such as the finger, ear lobe and toes become susceptible to inaccuracies when peripheral perfusion is compromised. To overcome these limitations, the external auditory canal has been proposed as an alternative monitoring site for estimating SpO2, on the hypothesis that this central site will be better perfused. Therefore, a dual wavelength optoelectronic probe along with a processing system was developed to investigate the suitability of measuring photoplethysmographic (PPG) signals and SpO2 in the human auditory canal. A pilot study was carried out in 15 healthy volunteers to validate the feasibility of measuring PPGs and SpO2 from the ear canal (EC), and comparative studies were performed by acquiring the same signals from the left index finger (LIF) and the right index finger (RIF) in conditions of induced peripheral vasoconstriction (right hand immersion in ice water). Good quality baseline PPG signals with high signal-to-noise ratio were obtained from the EC, the LIF and the RIF sensors. During the ice water immersion, significant differences in the amplitude of the red and infrared PPG signals were observed from the RIF and the LIF sensors. The average drop in amplitude of red and infrared PPG signals from the RIF was 52.7% and 58.3%. Similarly, the LIF PPG signal amplitudes have reduced by 47.52% and 46.8% respectively. In contrast, no significant changes were seen in the red and infrared EC PPG amplitude measurements, which changed by +2.5% and −1.2% respectively. The RIF and LIF pulse oximeters have failed to estimate accurate SpO2 in seven and four volunteers respectively, while the EC pulse oximeter has only failed in one volunteer. These results suggest that the EC may be a suitable site for reliable monitoring of PPGs and SpO2s even in the presence of peripheral

  14. Blood oxygenation level-dependent MRI for assessment of renal oxygenation

    Directory of Open Access Journals (Sweden)

    Neugarten J

    2014-11-01

    Full Text Available Joel Neugarten, Ladan Golestaneh Renal Division, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA Abstract: Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI has recently emerged as an important noninvasive technique to assess intrarenal oxygenation under physiologic and pathophysiologic conditions. Although this tool represents a major addition to our armamentarium of methodologies to investigate the role of hypoxia in the pathogenesis of acute kidney injury and progressive chronic kidney disease, numerous technical limitations confound interpretation of data derived from this approach. BOLD MRI has been utilized to assess intrarenal oxygenation in numerous experimental models of kidney disease and in human subjects with diabetic and nondiabetic chronic kidney disease, acute kidney injury, renal allograft rejection, contrast-associated nephropathy, and obstructive uropathy. However, confidence in conclusions based on data derived from BOLD MRI measurements will require continuing advances and technical refinements in the use of this technique. Keywords: kidney, hypoxia, oxygenation, diabetes mellitus, chronic kidney disease, acute kidney injury, contrast-associated nephropathy, BOLD MRI

  15. Detection of changes in muscle oxygen saturation in the human leg: a comparison of two near-infrared spectroscopy devices.

    Science.gov (United States)

    Nygren, Andreas; Rennerfelt, Kajsa; Zhang, Qiuxia

    2014-02-01

    The purpose of this study was first to evaluate the near infrared spectroscopy (NIRS) device, INVOS 4100 as a method of measuring exercise and arterial occlusion induced muscle ischemia in human leg, by comparison with InSpectra tissue spectrometer Model 325, and secondly to determine the influence of skin and subcutaneous thickness on the NIRS measurements. Twenty healthy subjects (43 ± 8 years) volunteered for the study. Tissue oxygen saturation (StO2) in the anterior tibial muscle was measured simultaneously with InSpectra Model 325 in one leg and INVOS 4100 in the contralateral leg during an exercise test until muscle exhaustion and arterial occlusion with and without exercise. The skin and subcutaneous thickness was identified by ultrasound imaging. Baseline StO2 was 87 ± 8 % detected by InSpectra and 76 ± 6 % by INVOS. Both devices detected an immediate decrease of StO2 (p exercise, arterial occlusion with and without exercise, and a significant post ischemic hyperaemia (p exercise (r = -0.65, p = 0.002) for InSpectra, which was not apparent for INVOS. The results demonstrate that the cerebral/somatic oxygenation monitor (INVOS) is able to detect experimentally induced skeletal muscle ischemia in the human leg as well as the peripheral tissue spectrometer (InSpectra). Muscle oxygen saturation measurement by INVOS is less affected by skin and subcutaneous thickness than measured by InSpectra. PMID:23846128

  16. Effect of Turkish music that premature infants are made to listen during care on stress, oxygen saturation level and length of hospital stay

    OpenAIRE

    Diler Aydın; Suzan Yıldız

    2014-01-01

    Research was planned as an experimental study in order to determine the effect of Turkish music performance applied during care in the neonatal intensive care unit on stress indicators, oxygen saturation, peak heart rate, respiration value and length of hospital stay. It was an experimental study (experimental n: 30; control n: 30). Preterm infants were made to listen Turkish music for 30 minutes every day. Stress indicators, oxygen saturation, peak heart rate and respiration values observed ...

  17. Improving the detectability of oxygen saturation level targets for preterm neonates: A laboratory test of tremolo and beacon sonifications.

    Science.gov (United States)

    Deschamps, Marie-Lys; Sanderson, Penelope; Hinckfuss, Kelly; Browning, Caitlin; Loeb, Robert G; Liley, Helen; Liu, David

    2016-09-01

    Recent guidelines recommend oxygen saturation (SpO2) levels of 90%-95% for preterm neonates on supplemental oxygen but it is difficult to discern such levels with current pulse oximetry sonifications. We tested (1) whether adding levels of tremolo to a conventional log-linear pulse oximetry sonification would improve identification of SpO2 ranges, and (2) whether adding a beacon reference tone to conventional pulse oximetry confuses listeners about the direction of change. Participants using the Tremolo (94%) or Beacon (81%) sonifications identified SpO2 range significantly more accurately than participants using the LogLinear sonification (52%). The Beacon sonification did not confuse participants about direction of change. The Tremolo sonification may have advantages over the Beacon sonification for monitoring SpO2 of preterm neonates, but both must be further tested with clinicians in clinically representative scenarios, and with different levels of ambient noise and distractions. PMID:27184324

  18. Skeletal Muscle Oxygen Saturation (StO2 Measured by Near-Infrared Spectroscopy in the Critically Ill Patients

    Directory of Open Access Journals (Sweden)

    J. Mesquida

    2013-01-01

    Full Text Available According to current critical care management guidelines, the overall hemodynamic optimization process seeks to restore macrocirculatory oxygenation, pressure, and flow variables. However, there is increasing evidence demonstrating that, despite normalization of these global parameters, microcirculatory and regional perfusion alterations might occur, and persistence of these alterations has been associated with worse prognosis. Such observations have led to great interest in testing new technologies capable of evaluating the microcirculation. Near-infrared spectroscopy (NIRS measures tissue oxygen saturation (StO2 and has been proposed as a noninvasive system for monitoring regional circulation. The present review aims to summarize the existing evidence on NIRS and its potential clinical utility in different scenarios of critically ill patients.

  19. Near-Infrared Spectroscopic Measurement of the Effect of Leg Dominance on Muscle Oxygen Saturation During Cycling

    Science.gov (United States)

    Ellerby, Gwenn E. C.; Lee, Stuart M. C.; Paunescu, Lelia Adelina; Pereira, Chelsea; Smith, Charles P.; Soller, Babs R.

    2011-01-01

    The effect of leg dominance on the symmetry of the biomechanics during cycling remains uncertain -- asymmetries have been observed in kinematics and kinetics, while symmetries were found in muscle activation. No studies have yet investigated the symmetry of muscle metabolism during cycling. Near-infrared spectroscopy (NIRS) provides a non-invasive method to investigate the metabolic responses of specific muscles during cycling. PURPOSE: To determine whether there was an effect of leg dominance on thigh muscle oxygen saturation (SmO2) during incrementally loaded submaximal cycling using NIRS. METHODS: Eight right leg dominant, untrained subjects (5 men, 3 women; 31+/-2 yrs; 168.6+/-1.0 cm; 67.2+/-1.8 kg, mean +/- SE) volunteered to participate. Spectra were collected bilaterally from the vastus lateralis (VL) during supine rest and cycling. SmO2 was calculated using previously published methods. Subjects pedaled at 65 rpm while resistance to pedaling was increased in 0.5 kp increments from 0.5 kp every 3 min until the subject reached 80% of age-predicted maximal heart rate. SmO2 was averaged over 3 min for each completed stage. A two-way ANOVA was performed to test for leg differences. A priori contrasts were used to compare work levels to rest. RESULTS: VL SmO2 was not different between the dominant and non-dominant legs at rest and during exercise (p=0.57). How SmO2 changed with workload was also not different between legs (p=0.32). SmO2 at 0.5 kp (60.3+/-4.0, p=0.12) and 1.0 kp (59.5+/-4.0, p=0.10) was not different from rest (69.1+/-4.0). SmO2 at 1.5 kp (55.4 4.0, p=0.02), 2.0 kp (55.7+/-5.0, p=0.04), and 2.5 kp (43.4+/-7.9, p=0.01) was significantly lower than rest. CONCLUSION: VL SmO2 during cycling is not different between dominant and non-dominant legs and decreases with moderate workload in untrained cyclists. Assuming blood flow is directed equally to both legs, similar levels of oxygen extraction (as indicated by SmO2) suggests the metabolic load of

  20. Assessment of the oxygen consumption in the backfill. Geochemical modelling in a saturated backfill

    Energy Technology Data Exchange (ETDEWEB)

    Grandia, Fidel; Domenech, Cristina; Arcos, David; Duro, Lara [Enviros Spain S.L., Barcelona (Spain)

    2006-11-15

    The consumption of oxygen in the deep disposal is a major concern due to the ability of this element to corrode the canisters where high level nuclear wastes (HLNW) are disposed. The anoxic conditions initially present in a deep geologic environment are disturbed by the excavation of the repository facilities. After sealing the deposition holes and tunnels using clay-based materials, oxygen remains dissolved in porewater or as a gas phase in the unsaturated pores. The main mechanisms of oxygen depletion that can be considered in the backfill materials are: (1) diffusion into the surrounding rock and (2) kinetic reactions with accessory minerals and organic matter existing in the backfill. In this report, a set of numerical simulations are carried out in one and two dimensions in order to test the effect on the oxygen concentration in the pore water of all these mechanisms. The backfill considered is a 0/70 mixture of MX-80 bentonite and crushed material from the excavation itself. In addition to organic matter, the solid phases with reducing capacity in the backfill are Fe(II)-bearing minerals: pyrite (FeS{sub 2}) and siderite (FeCO) (as accessory minerals in the bentonite) and Fe-biotite (from the crushed granite). In the simulations, other chemical processes like cation exchange and surface complexation onto clay surfaces, and thermodynamic equilibrium with calcite, gypsum and quartz are considered. Initial composition of porewater is obtained by equilibrating the Forsmark groundwater with the backfill material. The 1D simulation consists of a number of cells with no reactive minerals or organic matter representing granite. The central cell, however, contains oxygen and reactive minerals resembling a backfill. Oxygen is allowed to move only by diffusion. The 2D model simulates the interaction with a backfill of a granitic groundwater flowing through a fracture. Like in the 1D model, the backfill contains oxygen and reactive solids. The results are very similar in

  1. Assessment of the oxygen consumption in the backfill. Geochemical modelling in a saturated backfill

    International Nuclear Information System (INIS)

    The consumption of oxygen in the deep disposal is a major concern due to the ability of this element to corrode the canisters where high level nuclear wastes (HLNW) are disposed. The anoxic conditions initially present in a deep geologic environment are disturbed by the excavation of the repository facilities. After sealing the deposition holes and tunnels using clay-based materials, oxygen remains dissolved in porewater or as a gas phase in the unsaturated pores. The main mechanisms of oxygen depletion that can be considered in the backfill materials are: (1) diffusion into the surrounding rock and (2) kinetic reactions with accessory minerals and organic matter existing in the backfill. In this report, a set of numerical simulations are carried out in one and two dimensions in order to test the effect on the oxygen concentration in the pore water of all these mechanisms. The backfill considered is a 0/70 mixture of MX-80 bentonite and crushed material from the excavation itself. In addition to organic matter, the solid phases with reducing capacity in the backfill are Fe(II)-bearing minerals: pyrite (FeS2) and siderite (FeCO) (as accessory minerals in the bentonite) and Fe-biotite (from the crushed granite). In the simulations, other chemical processes like cation exchange and surface complexation onto clay surfaces, and thermodynamic equilibrium with calcite, gypsum and quartz are considered. Initial composition of porewater is obtained by equilibrating the Forsmark groundwater with the backfill material. The 1D simulation consists of a number of cells with no reactive minerals or organic matter representing granite. The central cell, however, contains oxygen and reactive minerals resembling a backfill. Oxygen is allowed to move only by diffusion. The 2D model simulates the interaction with a backfill of a granitic groundwater flowing through a fracture. Like in the 1D model, the backfill contains oxygen and reactive solids. The results are very similar in both

  2. A Model of Anterograde Oxygenated Lung Blood Flow in Acardia.

    Science.gov (United States)

    Marinakis, Sotirios; Burki, Marco; Abdel-Sayed, Saad; von Segesser, Ludwig Karl

    2016-01-01

    In extreme situations such as hyperacute rejection of heart transplant or major heart trauma, heart explantation and extracorporeal membrane oxygenation (ECMO) hemodynamic support might be the only means for survival. In our previous model of acardia, pulmonary artery (PA) was clamped and did not receive any anterograde blood flow. A model of anterograde PA perfusion might be necessary to avoid ischemic pulmonary damage in prolonged ECMO in acardia. The aim of this study was to describe the surgical technique and to determine the feasibility of an anterograde lung perfusion in acardia through the anastomosis of the right internal mammary artery (RIMA) to the PA. A venoarterial cardiopulmonary bypass was established in three pigs (72 ± 2.6 kg) by the transjugular insertion to the caval axis of a double-staged cannula with carotid artery return. Heart was excised and ECMO was established as previously reported. Right internal mammary artery was harvested and after measurement of its output (93.3 ± 5.8 ml/min, representing 2.17% ± 0.15% of total pump flow), it was anastomosed to PA. Right internal mammary artery anastomosis to PA is a feasible, safe, and easy to perform maneuver assuring an anterograde lung perfusion in acardia. PMID:27442854

  3. Modeling of Cerebral Oxygen Transport Based on In vivo Microscopic Imaging of Microvascular Network Structure, Blood Flow, and Oxygenation

    Science.gov (United States)

    Gagnon, Louis; Smith, Amy F.; Boas, David A.; Devor, Anna; Secomb, Timothy W.; Sakadžić, Sava

    2016-01-01

    Oxygen is delivered to brain tissue by a dense network of microvessels, which actively control cerebral blood flow (CBF) through vasodilation and contraction in response to changing levels of neural activity. Understanding these network-level processes is immediately relevant for (1) interpretation of functional Magnetic Resonance Imaging (fMRI) signals, and (2) investigation of neurological diseases in which a deterioration of neurovascular and neuro-metabolic physiology contributes to motor and cognitive decline. Experimental data on the structure, flow and oxygen levels of microvascular networks are needed, together with theoretical methods to integrate this information and predict physiologically relevant properties that are not directly measurable. Recent progress in optical imaging technologies for high-resolution in vivo measurement of the cerebral microvascular architecture, blood flow, and oxygenation enables construction of detailed computational models of cerebral hemodynamics and oxygen transport based on realistic three-dimensional microvascular networks. In this article, we review state-of-the-art optical microscopy technologies for quantitative in vivo imaging of cerebral microvascular structure, blood flow and oxygenation, and theoretical methods that utilize such data to generate spatially resolved models for blood flow and oxygen transport. These “bottom-up” models are essential for the understanding of the processes governing brain oxygenation in normal and disease states and for eventual translation of the lessons learned from animal studies to humans.

  4. Cerebral oxygen saturation monitoring during hypotensive anesthesia in shoulder arthroscopy: A comparative study between dexmedetomidine and esmolol

    OpenAIRE

    Khaled Mohammed Maghawry; Ashraf El Sayed El-Agamy; Wael Ibrahim Tahir; Ayman F. Zein

    2015-01-01

    Background: Beach chair position (BCP) is used in arthroscopic shoulder operations for its advantages. The BCP together with deliberate hypotension used to decrease intraoperative blood loss during arthroscopic shoulder procedures, this may have risk to cause postoperative neurological insults. Dexmedetomidine and esmolol are used to induce deliberate hypotension. Near-infrared spectroscopy (NIRS) provides a non-invasive technique of continuous monitoring of regional cerebral tissue oxygen sa...

  5. Oxygenation-sensitive CMR for assessing vasodilator-induced changes of myocardial oxygenation

    OpenAIRE

    Wang Jiun; Dharmakumar Rohan; Green Jordin D; Flewitt Jacqueline A; Vöhringer Matthias; Tyberg John V; Friedrich Matthias G

    2010-01-01

    Abstract Background As myocardial oxygenation may serve as a marker for ischemia and microvascular dysfunction, it could be clinically useful to have a non-invasive measure of changes in myocardial oxygenation. However, the impact of induced blood flow changes on oxygenation is not well understood. We used oxygenation-sensitive CMR to assess the relations between myocardial oxygenation and coronary sinus blood oxygen saturation (SvO2) and coronary blood flow in a dog model in which hyperemia ...

  6. Noninvasive optical characterization of muscle blood flow, oxygenation, and metabolism in women with fibromyalgia

    OpenAIRE

    Shang, Yu; Gurley, Katelyn; Symons, Brock; Long, Douglas; Srikuea, Ratchakrit; Crofford., Leslie J.; Peterson, Charlotte A.; Yu, Guoqiang

    2012-01-01

    Introduction Women with fibromyalgia (FM) have symptoms of increased muscular fatigue and reduced exercise tolerance, which may be associated with alterations in muscle microcirculation and oxygen metabolism. This study used near-infrared diffuse optical spectroscopies to noninvasively evaluate muscle blood flow, blood oxygenation and oxygen metabolism during leg fatiguing exercise and during arm arterial cuff occlusion in post-menopausal women with and without FM. Methods Fourteen women with...

  7. The effects of chronic betaine supplementation on exercise performance, skeletal muscle oxygen saturation and associated biochemical parameters in resistance trained men.

    Science.gov (United States)

    Trepanowski, John F; Farney, Tyler M; McCarthy, Cameron G; Schilling, Brian K; Craig, Stuart A; Bloomer, Richard J

    2011-12-01

    Trepanowski, JF, Farney, TM, McCarthy, CG, Schilling, BK, Craig, SA, and Bloomer, RJ. The effects of chronic betaine supplementation on exercise performance, skeletal muscle oxygen saturation, and associated biochemical parameters in resistance trained men. J Strength Cond Res 25(12): 3461-3471, 2011-We examined the effects of chronic betaine supplementation on exercise performance and associated parameters in resistance trained men. Men were randomly assigned in a double-blind manner using a crossover design to consume betaine (2.5 g of betaine mixed in 500 ml of Gatorade®) or a placebo (500 ml of Gatorade®) for 14 days, with a 21-day washout period. Before and after each treatment period, tests of lower- and upper-body muscular power and isometric force were conducted, including a test of upper-body muscular endurance (10 sets of bench press exercise to failure). Muscle tissue oxygen saturation (StO2) during the bench press protocol was measured via near infrared spectroscopy. Blood samples were collected before and after the exercise test protocol for analysis of lactate, nitrate/nitrite (NOx), and malondialdehyde (MDA). When analyzed using a repeated measures analysis of variance, no significant differences were noted between conditions for exercise performance variables (p > 0.05). However, an increase in total repetitions (p = 0.01) and total volume load (p = 0.02) in the 10-set bench press protocol was noted with betaine supplementation (paired t-tests), with values increasing approximately 6.5% from preintervention to postintervention. Although not of statistical significance (p = 0.14), postexercise blood lactate increased to a lesser extent with betaine supplementation (210%) compared with placebo administration (270%). NOx was lower postintervention as compared with preintervention (p = 0.06), and MDA was relatively unchanged. The decrease in StO2 during the bench press protocol was greater with betaine vs. placebo (p = 0.01), possibly suggesting

  8. Relationship between muscle oxygenation by NIRS and blood lactate

    International Nuclear Information System (INIS)

    The aim of the study was to investigate the relationship of muscle oxygenation in term of oxy-hemoglobin concentration change (ΔHbO2) by NIRS and blood lactate (BLA) in local skeletal muscle and evaluate the capability of NIRS in the research of exercise physiology Twenty-three athlete in the national fin-swimming team took the increasing load training on the power bicycle while their ΔHbO2 and BLA were simultaneously recorded. The initial powers used in the training were set as 100 w for males and 40 w for females. During the experiment, the power kept constant for 3 min before each abrupt increment of 30 w until the limit of the athlete's capability. Statistical analysis and data visualization were performed. Following the increasing load training, ΔHbO2 step-likely increased in the phase of aerobic metabolism but linearly decreased in the phase of anaerobic metabolism. The variation tendency of BLA was the same as ΔHbO2 and the concurrency of crucial turning points between ΔHbO2 and BLA was revealed. This relationship between ΔHbO2 and BLA presented in the increasing load training suggested that ΔHbO2 might be capable for taking the place of the invasively measured parameter BLA. Considering that ΔHbO2 can be noninvasively measured by NIRS, ΔHbO2 has the potential in the evaluation of athletes' physiological function and training effect on the athletes and accordingly NIRS can be well used in this field.

  9. Relationship between muscle oxygenation by NIRS and blood lactate

    Energy Technology Data Exchange (ETDEWEB)

    Xu Guodong [School of Physical Education, Jianghan University, Hubei Wuhan 430056 (China); Mao Zongzhen; Ye Yanjie; Lv Kunru, E-mail: xguodong@wipe.edu.cn [School of Health Sciences, Wuhan Institute of Physical Education, Hubei Wuhan 430079 (China)

    2011-01-01

    The aim of the study was to investigate the relationship of muscle oxygenation in term of oxy-hemoglobin concentration change ({Delta}HbO{sub 2}) by NIRS and blood lactate (BLA) in local skeletal muscle and evaluate the capability of NIRS in the research of exercise physiology Twenty-three athlete in the national fin-swimming team took the increasing load training on the power bicycle while their {Delta}HbO{sub 2} and BLA were simultaneously recorded. The initial powers used in the training were set as 100 w for males and 40 w for females. During the experiment, the power kept constant for 3 min before each abrupt increment of 30 w until the limit of the athlete's capability. Statistical analysis and data visualization were performed. Following the increasing load training, {Delta}HbO{sub 2} step-likely increased in the phase of aerobic metabolism but linearly decreased in the phase of anaerobic metabolism. The variation tendency of BLA was the same as {Delta}HbO{sub 2} and the concurrency of crucial turning points between {Delta}HbO{sub 2} and BLA was revealed. This relationship between {Delta}HbO{sub 2} and BLA presented in the increasing load training suggested that {Delta}HbO{sub 2} might be capable for taking the place of the invasively measured parameter BLA. Considering that {Delta}HbO{sub 2} can be noninvasively measured by NIRS, {Delta}HbO{sub 2} has the potential in the evaluation of athletes' physiological function and training effect on the athletes and accordingly NIRS can be well used in this field.

  10. Investigation of source-detector separation optimization for an implantable perfusion and oxygenation sensor for liver blood vessels

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Justin S [ORNL; Akl, Tony [Texas A& M University; Cote, Gerard L. [Texas A& M University; Wilson, Mark A. [University of Pittsburgh School of Medicine, Pittsburgh PA; Ericson, Milton Nance [ORNL

    2011-01-01

    An implanted system is being developed to monitor transplanted liver health during the critical 7-10 day period posttransplantation. The unit will monitor organ perfusion and oxygen consumption using optically-based probes placed on both the inflow and outflow blood vessels, and on the liver parenchymal surface. Sensing probes are based on a 3- wavelength LED source and a photodiode detector. Sample diffuse reflectance is measured at 735, 805, and 940 nm. To ascertain optimal source-to-photodetector spacing for perfusion measurement in blood vessels, an ex vivo study was conducted. In this work, a dye mixture simulating 80% blood oxygen saturation was developed and perfused through excised porcine arteries while collecting data for various preset probe source-to-photodetector spacings. The results from this study demonstrate a decrease in the optical signal with decreasing LED drive current and a reduction in perfusion index signal with increasing probe spacing. They also reveal a 2- to 4-mm optimal range for blood vessel perfusion probe source-to-photodetector spacing that allows for sufficient perfusion signal modulation depth with maximized signal to noise ratio (SNR). These findings are currently being applied to guide electronic configuration and probe placement for in vivo liver perfusion porcine model studies.

  11. IMPACT OF RED BLOOD CELL TRANSFUSION ON GLOBAL AND REGIONAL MEASURES OF OXYGENATION

    OpenAIRE

    Roberson, Russell S.; Bennett-Guerrero, Elliott

    2012-01-01

    Anemia is common in critically ill patients. While the goal of transfusion of red blood cells (RBCs) is to increase oxygen carrying capacity, there are contradictory results about whether RBC transfusion to treat moderate anemia (e.g. hemoglobin 7–10 g/dL) improves tissue oxygenation or changes outcomes. While increasing levels of anemia eventually lead to a level of critical oxygen delivery (DO2), increased cardiac output and oxygen extraction are homestatic mechanisms the body uses to preve...

  12. Positron emission tomography in cerebrovascular disease: The relationship between regional cerebral blood flow, blood volume and oxygen metabolism

    International Nuclear Information System (INIS)

    Positron emission tomography in cerebrovascular disease has demonstrated the importance of the relationship between regional cerebral blood flow and the cerebral metabolic activity. In acute stroke it has been found that within the first hours after the onset of symptoms cerebral blood flow in the affected area is more depressed than cerebral oxygen utilisation. This relative preservation of oxygen utilisation results from an increase in the oxygen extraction ratio far above its normal value. However, the oxygen extraction fraction subsequently falls in the following days indicating the transition from a situation of possibly reversible ischaemia to irreversible infarction. In patients with carotid occlusive disease an increase in the oxygen extraction ratio has been observed only in very few cases. It has been shown, however, that at an earlier stage the relationship between CBF and CBV (as CBF/CBV-ratio) provides a sensitive measure of diminished perfusion pressure which could be helpful for the selection of patients for EC-IC bypass surgery. In patients with sickle cell anaemia it has been found that oxygen delivery to the brain is maintained by an increase in cerebral blood flow, whereas the oxygen extraction ratio is not increased despite the presence of a low oxygen affinity haemoglobin. Preliminary observations in classical migraine suggest an ischaemic situation during the attack. (orig.)

  13. Theoretical considerations to optimize transabdominal monitoring of fetal arterial blood oxygenation using pulse oximetry

    Science.gov (United States)

    Zourabian, Anna; Boas, David A.

    2001-06-01

    Pulse oximetry (oxygen saturation monitoring) has markedly improved medical care in many fields, including anesthesiology, intensive care, and newborn intensive care. In obstetrics, fetal heart rate monitoring remains the standard for intrapartum assessment of fetal well being. Fetal oxygen saturation monitoring is a new technique currently under development. It is potentially superior to electronic fetal heart rate monitoring (cardiotocography) because it allows direct assessment of both fetal oxygen status and fetal tissue perfusion. Here we present the analysis for determining the most optimal wavelength selection for pulse oximetry. The wavelengths we chose as the most optimal are: the first in the range of 670-720nm and the second in the range of 825-925nm. Further we discuss the possible systematic errors during our measurements, and their contribution to the obtained saturation results.

  14. [Studying the influence of some reactive oxygen species on physical and chemical parameters of blood].

    Science.gov (United States)

    Martusevich, A K; Martusevich, A A; Solov'eva, A G; Peretyagin, S P

    2014-01-01

    The aim of this work was to estimate the dynamics of blood physical and chemical parameters when blood specimens were processed by singlet oxygen in vitro. Our experiments were executed with whole blood specimens of healthy people (n=10). Each specimen was divided into five separate portions of 5 ml. The first portion was a control (without any exposures). The second one was processed by an oxygen-ozone mixture (at ozone concentration of 500 mcg/l, the third portion--by oxygen, and the fourth and fifth ones were processed by a gas mixture with singlet oxygen (50 and 100% of generator power). In blood samples after processing we studied the activity of lactate dehydrogenase, aldehyde dehydrogenase and superoxide dismutase, erythrocyte and plasma levels of glucose and lactate, acid-base balance and the partial pressure of gases in blood. It was found out, that blood processing by singlet oxygen leads to optimization of energy, detoxication and antioxidant enzymes functioning with changes in plasma and erythrocyte level of glucose and lactate, normalization of blood gases level and acid-base balance. Our results show, that the effect of singlet oxygen on enzyme activity is more pronounced than exposure to an oxygen-ozone gas mixture. PMID:25702489

  15. HyperCEST detection of cucurbit[6]uril in whole blood using an ultrashort saturation Pre-pulse train.

    Science.gov (United States)

    Hane, Francis T; Smylie, Peter S; Li, Tao; Ruberto, Julia; Dowhos, Krista; Ball, Iain; Tomanek, Boguslaw; DeBoef, Brenton; Albert, Mitchell S

    2016-07-01

    Xenon based biosensors have the potential to detect and localize biomarkers associated with a wide variety of diseases. The development and nuclear magnetic resonance (NMR) characterization of cage molecules which encapsulate hyperpolarized xenon is imperative for the development of these xenon biosensors. We acquired (129) Xe NMR spectra, and magnetic resonance images and a HyperCEST saturation map of cucurbit[6]uril (CB6) in whole bovine blood. We observed a mean HyperCEST depletion of 84% (n = 5) at a concentration of 5 mM and 74% at 2.5 mM. Additionally, we collected these data using a pulsed HyperCEST saturation pre-pulse train with a SAR of 0.025 W/kg which will minimize any potential RF heating in animal or human tissue. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27071809

  16. Specificity of Compensatory Reserve and Tissue Oxygenation as Early Predictors of Tolerance to Progressive Reductions in Central Blood Volume.

    Science.gov (United States)

    Howard, Jeffrey T; Janak, Jud C; Hinojosa-Laborde, Carmen; Convertino, Victor A

    2016-09-01

    We previously reported that measurements of muscle oxygen saturation (SmO2) and the compensatory reserve index (CRI) provided earlier indication of reduced central blood volume than standard vital signs (e.g., blood pressure, heart rate, arterial oxygen saturation). In the present study, we hypothesized that the CRI would provide greater sensitivity and specificity to detect progressive decrease in central circulating blood volume compared with SmO2. Continuous noninvasive measures of CRI (calculated from feature changes in the photoplethysmographic arterial waveforms) were collected from 55 healthy volunteer subjects before and during stepwise lower body negative pressure (LBNP) to the onset of hemodynamic decompensation. Near infrared spectroscopy was used on the forearm to obtain deep SmO2, hydrogen ion concentration ([H]), and hemoglobin volume (HbT; decreases reflect vasoconstriction). CRI decreased by 97% in a linear fashion across progressive blood volume loss, with no clinically significant alterations in vital signs. The receiver operating characteristic (ROC) area under the curve (AUC) for the CRI was 0.91, with a sensitivity of 0.87 and specificity of 0.80, when predicting decompensation at progressive levels of LBNP. In comparison, SmO2, [H], and HbT had significantly lower ROC AUC, sensitivity and specificity values for detecting the same outcome. Consistent with our hypothesis, CRI detected central hypovolemia with significantly greater specificity than measures of tissue metabolism. Single measurement of CRI may enable more accurate triage, while CRI monitoring may allow for earlier detection of casualty deterioration. PMID:27058052

  17. Blood oxygenation level dependent (BOLD). Renal imaging. Concepts and applications; Blood Oxygenation Level Dependent (BOLD). Bildgebung der Nieren. Konzepte und Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Nissen, Johanna C.; Haneder, Stefan; Schoenberg, Stefan O.; Michaely, Henrik J. [Heidelberg Univ. Medizinische Fakultaet Mannheim (Germany). Inst. fuer Klinische Radiologie und Nuklearmedizin; Mie, Moritz B.; Zoellner, Frank G. [Heidelberg Univ. Medizinische Fakultaet Mannheim (DE). Inst. fuer Computerunterstuetzte Klinische Medizin (CKM)

    2010-07-01

    Many renal diseases as well as several pharmacons cause a change in renal blood flow and/or renal oxygenation. The blood oxygenation level dependent (BOLD) imaging takes advantage of local field inhomogeneities and is based on a T2{sup *}-weighted sequence. BOLD is a non-invasive method allowing an estimation of the renal, particularly the medullary oxygenation, and an indirect measurement of blood flow without administration of contrast agents. Thus, effects of different drugs on the kidney and various renal diseases can be controlled and observed. This work will provide an overview of the studies carried out so far and identify ways how BOLD can be used in clinical studies. (orig.)

  18. A numerical model of blood oxygenation during veno-venous ECMO: analysis of the interplay between blood oxygenation and its delivery parameters.

    Science.gov (United States)

    Messai, Elmi; Bouguerra, Abdesselam; Harmelin, Guy; Di Lascio, Gabriella; Bonizzoli, Manuela; Bonacchi, Massimo

    2016-06-01

    Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is an important tool in the management of most severe forms of acute respiratory failure. The determinants and management of oxygen delivery in patients treated with VV-ECMO is a complex topic. The physiological principles of oxygenation on VV-ECMO are reviewed in many textbooks. However a numerical model is an additional instrument to be used in understanding and exploring this intricate subject matter. We present a numerical model of blood oxygenation during VV-ECMO. Using this model we examined the role and impact of each determinant on blood oxygenation. The numerical analysis of variation and interplay between each oxygenation determinants during VV-ECMO is presented in graphical form. These results corroborate all the findings of previous studies. The proposed numerical model facilitates understanding of oxygenation physiology during VV-ECMO; it can be used for a medical simulation system and for teaching the principles of oxygenation during VV-ECMO. PMID:26091774

  19. HEMORHEOLOGICAL IMPLICATIONS OF PERFLUOROCARBON BASED OXYGEN CARRIER INTERACTION WITH COLLOID PLASMA EXPANDERS AND BLOOD

    OpenAIRE

    Vásquez, Diana M.; Ortiz, Daniel; Alvarez, Oscar A.; Briceño, Juan C.; Cabrales, Pedro

    2013-01-01

    Perfluorocarbon (PFC) emulsion based oxygen carriers lack colloid osmotic pressure (COP) and must be administered with colloid-based plasma expanders (PEs). Although PFC emulsions have been widely studied, there is limited information about PFC emulsion interaction with PEs and blood. Their interaction forms aggregates due to electrostatic and rheological phenomena, and change blood rheology and blood flow. This study analyzes the effects of the interaction between PFC emulsions with blood in...

  20. Corrosion Resistance of Steels and Armco-Fe in Lead Melt Saturated by Oxygen at 550 degree C

    International Nuclear Information System (INIS)

    Corrosion resistance of stainless steels and Armco-Fe in static lead melt saturated by oxygen at 550 degree C for 2000 h was investigated. It was determined that double oxide layer was formed on the surface of investigated materials. Outer part of double oxide growths from the initial interface 'solid metal/liquid lead' towards the melt and consists of Fe3O4. Inner part of double oxide based on the matrix is composed of Fe3O4 for Armco-Fe, Fe1+xCr2-xO4 for martensitic 0.2 C-13 Cr and ferritic-martensitic EP823 steels and Fe1+xCr2-xO4+Ni for austenitic 18Cr-10Ni-1Ti. Lead did not penetrate into the matrix of tested materials and was detected only in the scale formed on austenitic steel

  1. Poincaré analysis of an overnight arterial oxygen saturation signal applied to the diagnosis of sleep apnea hypopnea syndrome

    International Nuclear Information System (INIS)

    The analysis of oxygen desaturations is a basic variable in polysomnographic studies for the diagnosis of sleep apnea. Several algorithms operating in the time domain already exist for sleep apnea detection via pulse oximetry, but in a disadvantageous way—they achieve either a high sensitivity or a high specificity. The aim of this study was to assess whether an alternative analysis of arterial oxygen saturation (SaO2) signals from overnight pulse oximetry could yield essential information on the diagnosis of sleep apnea hypopnea syndrome (SAHS). SaO2 signals from 117 subjects were analyzed. The population was divided into a learning dataset (70 patients) and a test set (47 patients). The learning set was used for tuning thresholds among the applied Poincaré quantitative descriptors. Results showed that the presence of apnea events in SAHS patients caused an increase in the SD1 Poincaré parameter. This conclusion was assessed prospectively using the test dataset. 90.9% sensitivity and 84.0% specificity were obtained in the test group. We conclude that Poincaré analysis could be useful in the study of SAHS, contributing to reduce the demand for polysomnographic studies in SAHS screening

  2. Radiosensitization by oxygen in ehrlich tumor receiving artificial blood substitute (FOB 20%)

    International Nuclear Information System (INIS)

    To enhance tissue PO2 of radioresistant hypoxic cells of tumor, artificial blood substitute (FOB) was applied, because it is excellent solvent for oxygen and allows the blood circulation system to recover and consequently increase the oxygen supply from blood to the tissue. When transplanted Ehrlich tumor of mice on thigh grew about 1,000 mm3 in volume, those were divided into three groups, group 1: 60Co γ-ray irradiation alone, group 2: irradiation under breathing oxygen, and group 3: irradiation under breathing oxygen after exchange transfusion with FOB. The radiosensitization of FOB was studied by compairing with the OER values of three groups for 50% TGD time, 50% SD time, and 50% and 75% TCP. The OER values of 50% TGD time, 5, 10 and 50% SD time 10 of oxygen group were 1.46, 1.29, and 1.22, respectively, and oxygen effect was observed in this group. Those values of FOB group were 2.02, 1.56, and 1.56, respectively and oxygen effect of FOB group was greater than those of oxygen group. Animals receiving FOB were apparently radiosensitized by oxygen against animals breathing oxygen at small doses irradiation effect (50% TGD time, and 50% SD time). The OER values of 50% and 75% TCP at 30 days and 90 days after irradiation of oxygen group were about 1.5 (1.46-1.61) and these of FOB group about 1.3 (1.15-1.38). Radiosensitization by oxygen of animals receiving FOB was not clearly recognized a gainst animals breathing oxygen in TCP effect at high dose irradiation. These results indicate that radioresistant hypoxic cells of tumor receiving artificial blood substitute (FOB) increase the sensitivity of 60Co γ-ray irradiation, especially at small dose irradiation. (author)

  3. Near-infrared spectroscopy measurement of blood oxygenation content and its application in sports practice

    Science.gov (United States)

    Xu, Guodong; Gong, Hui; Ge, Xinfa; Luo, Qingming

    2003-12-01

    To research the change characteristics of blood oxygenation content in skeletal muscle, the change regularity between blood oxygenation content and exercise intensity as well as HbO2 and blood lactate acid while taking incremental exercises, we took an in vivo, real-time and continuous measurement on the blood oxygenation content of eight sportsmen when they did incremental exercises of five degrees on a power bicycle using a portable tissue oximeter which is based on the principle of near-infrared spectroscopy(NIRS), simultaneously, we detected the blood lactate acid of subjects after each degree of incremental physical load instantly using a blood lactate analysis equipment. The results showed that the content of HbO2 descended regularly while that of Hb ascended; blood volume decreased; and the density of lactate increased as the intensity of exercises was heightened. The statistics analyses showed that the relationship between HbO2 and blood lactate is rather close (correlation coefficient r=-0.918). With this discovery, a theoretical basis in measuring the relative change of blood oxygenation content non-invasively was evidenced, and a novel technology for assessing the physical situation of sportsman, grasping sports density and evaluating the training effect could be imported.

  4. Esmolol added in repeated, cold, oxygenated blood cardioplegia improves myocardial function after cardiopulmonary bypass

    OpenAIRE

    Dahle, Geir Olav; Salminen, Pirjo-Riitta; Moen, Christian Arvei; Eliassen, Finn; Jonassen, Anne K.; Haaverstad, Rune; Matre, Knut; Grong, Ketil

    2015-01-01

    Objective: This study investigated if the β-receptor blocking agent esmolol, added to standard oxygenated blood cardioplegia, improved myocardial function after weaning from bypass. Design: A block-randomized, blinded study. Setting: A university laboratory. Participants: Twenty anesthetized pigs, Norwegian Landrace. Interventions: After cardiopulmonary bypass, cardiac arrest was induced with cold (12°C), oxygenated blood cardioplegia, enriched with either esmolol or vehi...

  5. Controlled experimental aquarium system for multi-stressor investigation: carbonate chemistry, oxygen saturation, and temperature

    Directory of Open Access Journals (Sweden)

    E. E. Bockmon

    2013-02-01

    Full Text Available As the field of ocean acidification has grown, researchers have increasingly turned to laboratory experiments to understand the impacts of increased CO2 on marine organisms. However, other changes such as ocean warming and deoxygenation are occurring concurrently with the increasing CO2 concentrations, complicating the anthropogenic impact on organisms. This experimental aquarium design allows for independent regulation of CO2 concentration, O2 levels, and temperature in a controlled environment to study the impacts of multiple stressors. The system has the flexibility for a wide range of treatment chemistry, seawater volumes, and study organisms. Control of the seawater chemistry is achieved by equilibration of a chosen gas mixture with seawater using a Liqui-Cel® membrane contactor. Included as examples, two experiments performed using the system have shown control of CO2 between approximately 500–1400 μatm and O2 from 80–240 μmol kg−1. Temperature has been maintained to 0.5 °C or better in the range of 10–17 °C. On a weeklong timescale, control results in variability in pH of less than 0.007 pH units and in oxygen concentration less than 3.5 μmol kg−1. Longer experiments, over a month, have been completed with reasonable but lessened control, still better than 0.08 pH units and 13 μmol kg−1 O2. The ability to study the impacts of multiple stressors in the laboratory simultaneously, as well as independently, will be an important part of understanding the response of marine organisms to a high-CO2 world.

  6. RAPID COMMUNICATION: A novel time frequency-based 3D Lissajous figure method and its application to the determination of oxygen saturation from the photoplethysmogram

    Science.gov (United States)

    Addison, Paul S.; Watson, James N.

    2004-11-01

    We present a novel time-frequency method for the measurement of oxygen saturation using the photoplethysmogram (PPG) signals from a standard pulse oximeter machine. The method utilizes the time-frequency transformation of the red and infrared PPGs to derive a 3D Lissajous figure. By selecting the optimal Lissajous, the method provides an inherently robust basis for the determination of oxygen saturation as regions of the time-frequency plane where high- and low-frequency signal artefacts are to be found are automatically avoided.

  7. Trans-abdominal monitoring of fetal arterial blood oxygenation using pulse oximetry

    Science.gov (United States)

    Zourabian, Anna; Siegel, Andrew M.; Chance, Britton; Ramanujam, Nirmala; Rode, Martha; Boas, David A.

    2000-10-01

    Pulse oximetry (oxygen saturation monitoring) has markedly improved medical care in many fields, including anesthesiology, intensive care, and newborn intensive care. In obstetrics, fetal heart rate monitoring remains the standard for intrapartum assessment of fetal well being. Fetal oxygen saturation monitoring is a new technique currently under development. It is potentially superior to electronic fetal heart rate monitoring (cardiotocography) because it allows direct assessment of both the fetal oxygen status and fetal tissue perfusion. Here we present the analysis for determining the most optimal wavelength selection for pulse oximetry. The wavelengths we chose as the most optimal are the first in the range of 670 - 720 nm and the second in the range of 825 - 925 nm. Further, we discuss the possible systematic errors during our measurements and their contribution to the obtained saturation results. We present feasibility studies for fetal pulse oximetry, monitored noninvasively through the maternal abdomen. Our preliminary experiments show that the fetal pulse can be discriminated from the maternal pulse and thus, in principle, the fetal arterial oxygen saturation can be obtained. We present the methodology for obtaining these data, and discuss the dependence of our measurements on the fetal position with respect to the optode assembly.

  8. Preoperative regional cerebral oxygen saturation is a predictor of postoperative delirium in on-pump cardiac surgery patients: a prospective observational trial

    OpenAIRE

    Schoen, Julika; Meyerrose, Joscha; Paarmann, Hauke; Heringlake, Matthias; Hueppe, Michael; Berger, Klaus-Ulrich

    2011-01-01

    Introduction Postoperative delirium is an important problem in patients undergoing major surgery. Cerebral oximetry is a non-invasive method to detect imbalances in the cerebral oxygen supply/demand-ratio. Low preoperative cerebral oxygen saturation (ScO2) levels have been associated with postoperative delirium in non-cardiac surgery patients. The present prospective observational study determines the relationship between pre- and intra-operative ScO2 levels and postoperative delirium in pati...

  9. The jumbo squid, Dosidicus gigas (Ommastrephidae), living in oxygen minimum zones II: Blood-oxygen binding

    Science.gov (United States)

    Seibel, Brad A.

    2013-10-01

    Dosidicus gigas is a large, metabolically active squid that migrates across a strong oxygen and temperature gradient in the Eastern Pacific. Here we analyze the oxygen-binding properties of the squid's respiratory protein (hemocyanin, Hc) that facilitate such activity. A high Hc-oxygen affinity, strong temperature dependence, and pronounced pH sensitivity (P50=0.009T2.03, pH 7.4; Bohr coefficient=ΔlogP50/ΔpH=-1.55+0.034T) of oxygen binding facilitate night-time foraging in the upper water column, and support suppressed oxygen demand in hypoxic waters at greater depths. Expanding hypoxia may act to alter the species habitable depth range. This analysis supports the contention that ocean acidification could limit oxygen carrying capacity in squids at warmer temperature leading to reduced activity levels or altered distribution.

  10. Myocardial Ischemia: Lack of Coronary Blood Flow or Myocardial Oxygen Supply/Demand Imbalance?

    Science.gov (United States)

    Heusch, Gerd

    2016-07-01

    Regional myocardial blood flow and contractile function in ischemic myocardium are well matched, and there is no evidence for an oxygen supply/demand imbalance. Thus, myocardial ischemia is lack of coronary blood flow with electric, functional, metabolic, and structural consequences for the myocardium. All therapeutic interventions must aim to improve blood flow to ischemic myocardium as much and as quickly as possible. PMID:27390331

  11. The Effects of Massage with Coconut and Sunflower Oils on Oxygen Saturation of Premature Infants with Respiratory Distress Syndrome Treated With Nasal Continuous Positive Airway Pressure

    Directory of Open Access Journals (Sweden)

    Sousan Valizadeh

    2012-11-01

    Full Text Available Introduction: Nowadays particular emphasis is placed on the developmental aspects of premature infants care. Massage therapy is one of the best-known methods of caring. Due to the minimal touch policy in neonatal intensive care units (NICUs, massaging is not usually performed on premature infants. However, there is not sufficient evidence to support the claim that newborn infants with complex medical conditions should not be massaged. This study aimed to determine the effects of massage with coconut and sunflower oils on oxygen saturation of infants with respiratory distress syndrome (RDS treated with nasal continuous positive airway pressure (NCPAP. Methods: This was a randomized controlled trial on 90 newborns who were admitted to Alzahra Hospital (Tabriz, Iran. The infants were divided into control and massage therapy groups (massage with coconut and sunflower oils. Data was collected using a hospital documentation form. A 15-minute daily massage was performed for 3 days. Respiratory rate (RR, fraction of inspired oxygen (FiO2 and oxygen saturation were measured 5 minutes before the massage, 3 times during the massage, and 5 minutes after the massage. The collected data was analyzed using a mixed model. Results: In comparison to coconut oil and control groups, mean oxygen saturation of sunflower oil group was improved. In addition, the coconut massage group showed lower oxygen saturation than the control group but was all values were within the normal range. Although massage decreased oxygen saturation, there was no need to increase FiO2. Conclusion: Massage therapy can provide developmental care for infants treated with NCPAP.

  12. REACTIVE OXYGEN SPECIES IN WHOLE BLOOD, BLOOD PLASMA AND BREAST MILK: VALIDATION OF A POTENTIAL MARKER OF EXPOSURE AND EFFECT

    Science.gov (United States)

    Reactive oxygen species (ROS) are recognized to contribute to the pathobiology of many diseases. We have applied a simple chemiluminescent (CL) probe to detect ROS in various biological fluids (plasma, whole blood, urine and breast milk) in an environmental arsenic drinking wate...

  13. Novel optoacoustic system for noninvasive continuous monitoring of cerebral venous blood oxygenation

    Science.gov (United States)

    Petrov, Yuriy; Petrov, Irene Y.; Prough, Donald S.; Esenaliev, Rinat O.

    2012-02-01

    Traumatic brain injury (TBI) and spinal cord injury are a major cause of death for individuals under 50 years of age. In the USA alone, 150,000 patients per year suffer moderate or severe TBI. Moreover, TBI is a major cause of combatrelated death. Monitoring of cerebral venous blood oxygenation is critically important for management of TBI patients because cerebral venous blood oxygenation below 50% results in death or severe neurologic complications. At present, there is no technique for noninvasive, accurate monitoring of this clinically important variable. We proposed to use optoacoustic technique for noninvasive monitoring of cerebral venous blood oxygenation by probing cerebral veins such as the superior sagittal sinus (SSS) and validated it in animal studies. In this work, we developed a novel, medical grade optoacoustic system for continuous, real-time cerebral venous blood oxygenation monitoring and tested it in human subjects at normal conditions and during hyperventilation to simulate changes that may occur in patients with TBI. We designed and built a highly-sensitive optoacoustic probe for SSS signal detection. Continuous measurements were performed in the near infrared spectral range and the SSS oxygenation absolute values were automatically calculated in real time using a special algorithm developed by our group. Continuous measurements performed at normal conditions and during hyperventilation demonstrated that hyperventilation resulted in approximately 12% decrease of cerebral venous blood oxygenation.

  14. Lactate, endothelin, and central venous oxygen saturation as predictors of mortality in patients with Tetralogy of Fallot

    Directory of Open Access Journals (Sweden)

    Poonam Malhotra Kapoor

    2016-01-01

    Full Text Available Background: Lactate and central venous oxygen saturation (ScVO2 are well known biomarkers for adequacy of tissue oxygenation. Endothelin, an inflammatory marker has been associated with patient′s nutritional status and degree of cyanosis. The aim of this study was to explore the hypothesis that lactate, ScVO2 and endothelin before induction may be predictive of mortality in pediatric cardiac surgery. Methods: We conducted a prospective observational study of 150 pediatric (6 months to 12 years patients who were posted for intracardiac repair for tetralogy of fallot and measured lactate, ScVO2 and endothelin before induction (T1, 20 minutes after protamine administration (T2 and 24 hours after admission to ICU (T3. Results: Preinduction lactate and endothelin levels were found to predict mortality in patients of tetralogy of fallot with an odds ratio of 6.020 (95% CI 2.111-17.168 and 1.292(95% CI 1.091-1.531 respectively. In the ROC curve analysis for lactate at T1, the AUC was 0.713 (95% CI 0.526-0.899 P = 0.019. At the cutoff value of 1.750mmol/lt, the sensitivity and specificity for the prediction of mortality was 63.6% and 65.5%, respectively. For endothelin at T1, the AUC was 0.699 (95% CI 0.516-0.883, P = 0.028 and the cutoff value was ≤2.50 (sensitivity, 63.6%; specificity, 58.3 %. ScVO2 (odds ratio 0.85 at all three time intervals, suggested that improving ScVO2 can lead to 15% reduction in mortality. Conclusions: Lactate, ScVO2 and endothelin all showed association with mortality with lactate having the maximum prediction. Lactate was found to be an independent, reliable and cost-effective measure of prediction of mortality in patients with tetralogy of fallot.

  15. Noninvasive cerebral blood oxygenation monitoring: clinical test of multiwavelength optoacoustic system

    Science.gov (United States)

    Petrov, Y. Y.; Prough, D. S.; Petrova, I.; Patrikeev, I. A.; Cicenaite, I.; Esenaliev, R. O.

    2007-02-01

    Continuous monitoring of cerebral blood oxygenation is critically important for treatment of patients with life-threatening conditions like severe brain injury or during cardiac surgery. We designed and built a novel multiwavelength optoacoustic system for noninvasive, continuous, and accurate monitoring of cerebral blood oxygenation. We use an Optical Parametric Oscillator as a light source. We successfully tested the system in vitro as well as in vivo in large animals (sheep) through thick tissues overlying blood vessels which drain venous blood out of the brain (e.g., superior sagittal sinus or jugular vein). Here we present the results of clinical tests of the system for continuous noninvasive cerebral blood oxygenation monitoring in the internal jugular vein of healthy volunteers. We applied our custom-built optoacoustic probe (which incorporated a wide-band acoustic transducer and an optical fiber) to the neck area overlying the internal jugular vein. We performed measurements with volunteers at 18 wavelengths in the near-infrared spectral range. Despite a thick layer of overlying connective tissue and low energy used in the experiments, we recorded signals with high signal-to-noise ratios for all volunteers. We found that the temporal (independent of signal amplitude) parameters of recorded profiles for different levels of blood oxygenation correlated well with the spectrum of effective attenuation coefficients of blood.

  16. Red blood cell pH, the Bohr effect, and other oxygenation-linked phenomena in blood O2 and CO2 transport.

    Science.gov (United States)

    Jensen, F B

    2004-11-01

    The discovery of the S-shaped O2 equilibrium curve and the Bohr effect in 1904 stimulated a fertile and continued research into respiratory functions of blood and allosteric mechanisms in haemoglobin (Hb). The Bohr effect (influence of pH/CO2 on Hb O2 affinity) and the reciprocal Haldane effect (influence of HbO2 saturation on H+/CO2 binding) originate in the Hb oxy-deoxy conformational change and allosteric interactions between O2 and H+/CO2 binding sites. In steady state, H+ is passively distributed across the vertebrate red blood cell (RBC) membrane, and intracellular pH (pHi) changes are related to changes in extracellular pH, Hb-O2 saturation and RBC organic phosphate content. As the Hb molecule shifts between the oxy and deoxy conformation in arterial-venous gas transport, it delivers O2 and takes up CO2 and H+ in tissue capillaries (elegantly aided by the Bohr effect). Concomitantly, the RBC may sense local O2 demand via the degree of Hb deoxygenation and release vasodilatory agents to match local blood flow with requirements. Three recent hypotheses suggest (1) release of NO from S-nitroso-Hb upon deoxygenation, (2) reduction of nitrite to vasoactive NO by deoxy haems, and (3) release of ATP. Inside RBCs, carbonic anhydrase (CA) provides fast hydration of metabolic CO2 and ensures that the Bohr shift occurs during capillary transit. The formed H+ is bound to Hb (Haldane effect) while HCO3- is shifted to plasma via the anion exchanger (AE1). The magnitude of the oxylabile H+ binding shows characteristic differences among vertebrates. Alternative strategies for CO2 transport include direct HCO3- binding to deoxyHb in crocodilians, and high intracellular free [HCO3-] (due to high pHi) in lampreys. At the RBC membrane, CA, AE1 and other proteins may associate into what appears to be an integrated gas exchange metabolon. Oxygenation-linked binding of Hb to the membrane may regulate glycolysis in mammals and perhaps also oxygen-sensitive ion transport involved in

  17. Effect of slow versus rapid rewarming on jugular bulb oxygen saturation in adult patients undergoing open heart surgery

    Directory of Open Access Journals (Sweden)

    Mohmaed Shaaban Ali

    2014-01-01

    Full Text Available Background: A debate has appeared in the recent literature about the optimum rewarming strategy (slow vs. rapid for the best brain function. This study was designed to compare the effect of slow versus rapid rewarming on jugular bulb oxygen saturation (SjO 2 in adult patients undergoing open heart surgery. Materials and Methods: A total of 80 patients undergoing valve and adult congenital heart surgery were randomly allocated equally to rapid rewarming group 0.5 (0.136°C/min and slow rewarming group 0.219 (0.055°C/min in jugular bulb sampling was taken before, during and after surgery. Surgery was done at cardiopulmonary bypass (CPB temperature of 28-30°C and rewarming was performed at the end of the surgical procedure. Results: CPB time, rewarming period were significantly longer in the slow rewarming group. Significant difference was observed in the number of the desaturated patients (SjO 2 ≤ 50% between the two groups; 14 (35% in rapid rewarming versus 6 (15% in the slow rewarming group; P = 0.035 by Fisher′s exact test. Conclusions: Slow rewarming could reduce the incidence of SjO 2 desaturation during rewarming in adult patients undergoing open heart surgery.

  18. Reduced cerebral blood flow and oxygen metabolism in extremely preterm neonates with low-grade germinal matrix- intraventricular hemorrhage

    Science.gov (United States)

    Lin, Pei-Yi; Hagan, Katherine; Fenoglio, Angela; Grant, P. Ellen; Franceschini, Maria Angela

    2016-01-01

    Low-grade germinal matrix-intraventricular hemorrhage (GM-IVH) is the most common complication in extremely premature neonates. The occurrence of GM-IVH is highly associated with hemodynamic instability in the premature brain, yet the long-term impact of low-grade GM-IVH on cerebral blood flow and neuronal health have not been fully investigated. We used an innovative combination of frequency-domain near infrared spectroscopy and diffuse correlation spectroscopy (FDNIRS-DCS) to measure cerebral oxygen saturation (SO2) and an index of cerebral blood flow (CBFi) at the infant’s bedside and compute an index of cerebral oxygen metabolism (CMRO2i). We enrolled twenty extremely low gestational age (ELGA) neonates (seven with low-grade GM-IVH) and monitored them weekly until they reached full-term equivalent age. During their hospital stay, we observed consistently lower CBFi and CMRO2i in ELGA neonates with low-grade GM-IVH compared to neonates without hemorrhages. Furthermore, lower CBFi and CMRO2i in the former group persists even after the resolution of the hemorrhage. In contrast, SO2 does not differ between groups. Thus, CBFi and CMRO2i may have better sensitivity than SO2 in detecting GM-IVH-related effects on infant brain development. FDNIRS-DCS methods may have clinical benefit for monitoring the evolution of GM-IVH, evaluating treatment response, and potentially predicting neurodevelopmental outcome. PMID:27181339

  19. Reduced cerebral blood flow and oxygen metabolism in extremely preterm neonates with low-grade germinal matrix- intraventricular hemorrhage

    Science.gov (United States)

    Lin, Pei-Yi; Hagan, Katherine; Fenoglio, Angela; Grant, P. Ellen; Franceschini, Maria Angela

    2016-05-01

    Low-grade germinal matrix-intraventricular hemorrhage (GM-IVH) is the most common complication in extremely premature neonates. The occurrence of GM-IVH is highly associated with hemodynamic instability in the premature brain, yet the long-term impact of low-grade GM-IVH on cerebral blood flow and neuronal health have not been fully investigated. We used an innovative combination of frequency-domain near infrared spectroscopy and diffuse correlation spectroscopy (FDNIRS-DCS) to measure cerebral oxygen saturation (SO2) and an index of cerebral blood flow (CBFi) at the infant’s bedside and compute an index of cerebral oxygen metabolism (CMRO2i). We enrolled twenty extremely low gestational age (ELGA) neonates (seven with low-grade GM-IVH) and monitored them weekly until they reached full-term equivalent age. During their hospital stay, we observed consistently lower CBFi and CMRO2i in ELGA neonates with low-grade GM-IVH compared to neonates without hemorrhages. Furthermore, lower CBFi and CMRO2i in the former group persists even after the resolution of the hemorrhage. In contrast, SO2 does not differ between groups. Thus, CBFi and CMRO2i may have better sensitivity than SO2 in detecting GM-IVH-related effects on infant brain development. FDNIRS-DCS methods may have clinical benefit for monitoring the evolution of GM-IVH, evaluating treatment response, and potentially predicting neurodevelopmental outcome.

  20. Effects of race and sex on cerebral hemodynamics, oxygen delivery and blood flow distribution in response to high altitude

    Science.gov (United States)

    Liu, Jie; Liu, Yang; Ren, Li-Hua; Li, Li; Wang, Zhen; Liu, Shan-Shan; Li, Su-Zhi; Cao, Tie-Sheng

    2016-08-01

    To assess racial, sexual, and regional differences in cerebral hemodynamic response to high altitude (HA, 3658 m). We performed cross-sectional comparisons on total cerebral blood flow (TCBF = sum of bilateral internal carotid and vertebral arterial blood flows = QICA + QVA), total cerebrovascular resistance (TCVR), total cerebral oxygen delivery (TCOD) and QVA/TCBF (%), among six groups of young healthy subjects: Tibetans (2-year staying) and Han (Han Chinese) at sea level, Han (2-day, 1-year and 5-year) and Tibetans at HA. Bilateral ICA and VA diameters and flow velocities were derived from duplex ultrasonography; and simultaneous measurements of arterial pressure, oxygen saturation, and hemoglobin concentration were conducted. Neither acute (2-day) nor chronic (>1 year) responses showed sex differences in Han, except that women showed lower TCOD compared with men. Tibetans and Han exhibited different chronic responses (percentage alteration relative to the sea-level counterpart value) in TCBF (‑17% vs. 0%), TCVR (22% vs. 12%), TCOD (0% vs. 10%) and QVA/TCBF (0% vs. 2.4%, absolute increase), with lower resting TCOD found in SL- and HA-Tibetans. Our findings indicate racial but not sex differences in cerebral hemodynamic adaptations to HA, with Tibetans (but not Han) demonstrating an altitude-related change of CBF distribution.

  1. Effects of race and sex on cerebral hemodynamics, oxygen delivery and blood flow distribution in response to high altitude.

    Science.gov (United States)

    Liu, Jie; Liu, Yang; Ren, Li-Hua; Li, Li; Wang, Zhen; Liu, Shan-Shan; Li, Su-Zhi; Cao, Tie-Sheng

    2016-01-01

    To assess racial, sexual, and regional differences in cerebral hemodynamic response to high altitude (HA, 3658 m). We performed cross-sectional comparisons on total cerebral blood flow (TCBF = sum of bilateral internal carotid and vertebral arterial blood flows = QICA + QVA), total cerebrovascular resistance (TCVR), total cerebral oxygen delivery (TCOD) and QVA/TCBF (%), among six groups of young healthy subjects: Tibetans (2-year staying) and Han (Han Chinese) at sea level, Han (2-day, 1-year and 5-year) and Tibetans at HA. Bilateral ICA and VA diameters and flow velocities were derived from duplex ultrasonography; and simultaneous measurements of arterial pressure, oxygen saturation, and hemoglobin concentration were conducted. Neither acute (2-day) nor chronic (>1 year) responses showed sex differences in Han, except that women showed lower TCOD compared with men. Tibetans and Han exhibited different chronic responses (percentage alteration relative to the sea-level counterpart value) in TCBF (-17% vs. 0%), TCVR (22% vs. 12%), TCOD (0% vs. 10%) and QVA/TCBF (0% vs. 2.4%, absolute increase), with lower resting TCOD found in SL- and HA-Tibetans. Our findings indicate racial but not sex differences in cerebral hemodynamic adaptations to HA, with Tibetans (but not Han) demonstrating an altitude-related change of CBF distribution. PMID:27503416

  2. Cerebral blood flow, oxygen and glucose metabolism with PET in progressive supranuclear palsy

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Makoto; Ichiya, Yuici; Kuwabara, Yasuo (Kyushu Univ., Fukuoka (Japan). Faculty of Medicine) (and others)

    1989-11-01

    Cerebral blood flow, cerebral oxygen metabolic rate and cerebral glucose metabolic rate were measured with positron emission tomography (PET) in four patients with progressive supranuclear palsy (PSP). Decreased blood flow and hypometabolism of oxygen and glucose were found in both subcortical and cortical regions, particularly in the striatum including the head of the caudate nucleus and the frontal cortex. The coupling between blood flow and metabolism was preserved even in the regions which showed decreased blood flow and hypometabolism. These findings indicated the hypofunction, as revealed by decreased blood flow and hypometablolism on PET, both in the striatum and the frontal cortex, and which may underlie the pathophysiological mechanism of motor and mental disturbance in PSP. (author).

  3. Cerebral blood flow, oxygen and glucose metabolism with PET in progressive supranuclear palsy

    International Nuclear Information System (INIS)

    Cerebral blood flow, cerebral oxygen metabolic rate and cerebral glucose metabolic rate were measured with positron emission tomography (PET) in four patients with progressive supranuclear palsy (PSP). Decreased blood flow and hypometabolism of oxygen and glucose were found in both subcortical and cortical regions, particularly in the striatum including the head of the caudate nucleus and the frontal cortex. The coupling between blood flow and metabolism was preserved even in the regions which showed decreased blood flow and hypometabolism. These findings indicated the hypofunction, as revealed by decreased blood flow and hypometablolism on PET, both in the striatum and the frontal cortex, and which may underlie the pathophysiological mechanism of motor and mental disturbance in PSP. (author)

  4. A new utilization area for hyperbaric oxygen? Improving quality of stored blood

    OpenAIRE

    Ay, Hakan; Yüksel, Ramazan; ŞİMŞEK, Kemal; Topal, Turgut; YEŞİLYURT, Özgur; ÖTER, Şükrü; Korkmaz, Ahmet; ÖZLER, Mehmet; Uysal, Bülent; Yaman, Halil; BEDİR, Orhan; BİLGİÇ, Hayati

    2015-01-01

    Since blood bags have the ability for diffusion of gases, we investigated whether hyperbaric oxygen (HBO) exposure affects several vital parameters of stored blood. Materials and methods: Bloods obtained from the same persons were used as both control and HBO groups and stored in pediatric bags with citrate-phosphate-dextrose solution. HBO administration was performed at 2.5 atm for 90 min, started 1 day after blood collection and repeated every 2 days for a total of 10 times. The study was ...

  5. Retinal oxygen extraction in humans

    OpenAIRE

    René M. Werkmeister; Doreen Schmidl; Gerold Aschinger; Veronika Doblhoff-Dier; Stefan Palkovits; Magdalena Wirth; Gerhard Garhöfer; Linsenmeier, Robert A.; Rainer A. Leitgeb; Leopold Schmetterer

    2015-01-01

    Adequate function of the retina is dependent on proper oxygen supply. In humans, the inner retina is oxygenated via the retinal circulation. We present a method to calculate total retinal oxygen extraction based on measurement of total retinal blood flow using dual-beam bidirectional Doppler optical coherence tomography and measurement of oxygen saturation by spectrophotometry. These measurements were done on 8 healthy subjects while breathing ambient room air and 100% oxygen. Total retinal b...

  6. Oxygenated-blood colour change thresholds for perceived facial redness, health, and attractiveness.

    Directory of Open Access Journals (Sweden)

    Daniel E Re

    Full Text Available Blood oxygenation level is associated with cardiovascular fitness, and raising oxygenated blood colouration in human faces increases perceived health. The current study used a two-alternative forced choice (2AFC psychophysics design to quantify the oxygenated blood colour (redness change threshold required to affect perception of facial colour, health and attractiveness. Detection thresholds for colour judgments were lower than those for health and attractiveness, which did not differ. The results suggest redness preferences do not reflect a sensory bias, rather preferences may be based on accurate indications of health status. Furthermore, results suggest perceived health and attractiveness may be perceptually equivalent when they are assessed based on facial redness. Appearance-based motivation for lifestyle change can be effective; thus future studies could assess the degree to which cardiovascular fitness increases face redness and could quantify changes in aerobic exercise needed to increase facial attractiveness.

  7. Effects of Feeding Periods of High Cholesterol and Saturated Fat Diet on Blood Biochemistry and Hydroxyproline Fractions in Rabbits

    Directory of Open Access Journals (Sweden)

    N. J. Siddiqi

    2008-01-01

    Full Text Available Hypercholesterolemia and hypertriglyceridemia are considered as important risk factors during the atherosclerotic process. The aim of the present investigation was to study the total cholesterol (TC, low-density lipoprotein cholesterol (LDLC, high density lipoprotein (HDL, triglyceride (TG, platelet levels and hydroxyproline fractions during the pathogenesis of atherosclerosis. For this purpose, twenty five 12-weeks, New Zealand white male rabbits, were purchased, individually caged, and divided into either control group or cholesterol-fed group. The control group (n = 10 was fed 100 g/day of normal diet, ORC-4 (Oriental Yeast Co. Ltd., Tokyo, Japan for a period of 15 weeks. The cholesterol-fed group (n = 15 was fed a high cholesterol and saturated fat diet of ORC-4 containing 1% cholesterol plus 1% olive oil (100 g/day for periods of 5 (group 1, 10 (group 2 and 15 (group 3 weeks. Blood sample from each animal was taken at the end of the experimental period for the biochemical analysis. The results of the present study showed that TC, LDLC, TG, HDLC and platelets were significantly (P0.05. There was no significant (P>0.05 decrease of free serum hydroxyproline in group 3 rabbits when compared to control rabbits. On the other hand, group 3 rabbits showed a significant increase in peptide–bound and protein- bound Hyp by 517% (P0.05 change when compared to control rabbits. These results suggest that feeding rabbits high cholesterol and saturated fat diet for feeding periods of 5 , 10 and 15 weeks induced significant change in TC, LDLC, HDL, TG, platelet levels and various Hyp fractions in serum without any significant change in the total Hyp content.

  8. Oxygen-implanted induced formation of oxide layer enhances blood compatibility on titanium for biomedical applications.

    Science.gov (United States)

    Hung, Wei-Chiang; Chang, Fang-Mo; Yang, Tzu-Sen; Ou, Keng-Liang; Lin, Che-Tong; Peng, Pei-Wen

    2016-11-01

    Titanium dioxide (TiO2) layers were prepared on a Ti substrate by using oxygen plasma immersion ion implantation (oxygen PIII). The surface chemical states, structure, and morphology of the layers were studied using X-ray photoelectron spectroscopy, X-ray diffraction, Raman microscopy, atomic force microscopy and scanning electron microscope. The mechanical properties, such as the Young's modulus and hardness, of the layers were investigated using nanoindentation testing. The Ti(4+) chemical state was determined to be present on oxygen-PIII-treated surfaces, which consisted of nanocrystalline TiO2 with a rutile structure. Compared with Ti substrates, the oxygen-PIII-treated surfaces exhibited decreased Young's moduli and hardness. Parameters indicating the blood compatibility of the oxygen-PIII-treated surfaces, including the clotting time and platelet adhesion and activation, were studied in vitro. Clotting time assays indicated that the clotting time of oxygen-PIII-treated surfaces was longer than that of the Ti substrate, which was associated with decreased fibrinogen adsorption. In conclusion, the surface characteristics and the blood compatibility of Ti implants can be modified and improved using oxygen PIII. PMID:27524050

  9. Acupressure at the Meridian Acupoint Xiyangguan (GB33 Influences Near-Infrared Spectroscopic Parameters (Regional Oxygen Saturation in Deeper Tissue of the Knee in Healthy Volunteers

    Directory of Open Access Journals (Sweden)

    Gerhard Litscher

    2013-01-01

    Full Text Available Up to now, it is still unknown whether microcirculation of deeper peripheral tissue (knee can be modulated by acupuncture or acupressure on a meridian acupoint. The goal of this pilot study was to investigate possible effects of acupressure at the Xiyangguan acupoint (GB33 on the regional oxygen saturation of the deeper knee tissues by near-infrared spectroscopy (NIRS. Twelve healthy volunteers with a mean age of 23.8±1.6 years were investigated. Acupressure stimulation was performed for 5 minutes at the Xiyangguan acupoint. The results of the controlled study showed a significant increase of the values of regional oxygen saturation on the stimulated side of the knee (P=0.033, whereas the opposite side on the same knee showed insignificant changes. These results may serve as a valuable basis for monitoring a possible therapeutic effect (e.g., after Khalifa therapy in patients with knee problems.

  10. Noninvasive imaging of hemoglobin concentration and oxygen saturation for detection of osteoarthritis in the finger joints using multispectral three-dimensional quantitative photoacoustic tomography

    International Nuclear Information System (INIS)

    We present quantitative imaging of hemoglobin concentration and oxygen saturation in in vivo finger joints and evaluate the feasibility of detecting osteoarthritis (OA) in the hand using three-dimensional (3D) multispectral quantitative photoacoustic tomography (3D qPAT). The results show that both the anatomical structures and quantitative chromophore concentrations (oxy-hemoglobin and deoxy-hemoglobin) of different joint tissues (hard phalanges and soft cartilage/synovial fluid between phalanges) can be imaged in vivo with the multispectral 3D qPAT. Enhanced hemoglobin concentrations and dropped oxygen saturations in osteoarthritic phalanges and soft joint tissues in joint cavities have been observed. This study indicates that the multispectral 3D qPAT is a promising approach to detect the angiogenesis and hypoxia associated with OA disease and a potential clinical tool for early OA detection in the finger joints. (paper)

  11. Tackling the Saturation of Oxygen: The Use of Phosphorus and Sulphur as Proxies Within the Neutral ISM of Star-Forming Galaxies

    OpenAIRE

    James, Bethan L.; Aloisi, Alessandra

    2015-01-01

    The abundance of oxygen in galaxies is widely used in furthering our understanding of galaxy formation and evolution. Unfortunately, direct measurements of O/H in the neutral gas are extremely difficult to obtain due to the fact that the only OI line available within the HST UV wavelength range (1150-3200A) is often saturated. As such, proxies for oxygen are needed to indirectly derive an O/H via the assumption that solar ratios based on local Milky Way sight lines hold in different environme...

  12. Acupressure at the Meridian Acupoint Xiyangguan (GB33) Influences Near-Infrared Spectroscopic Parameters (Regional Oxygen Saturation) in Deeper Tissue of the Knee in Healthy Volunteers

    OpenAIRE

    Gerhard Litscher; Michael Ofner; Wei He; Lu Wang; Ingrid Gaischek

    2013-01-01

    Up to now, it is still unknown whether microcirculation of deeper peripheral tissue (knee) can be modulated by acupuncture or acupressure on a meridian acupoint. The goal of this pilot study was to investigate possible effects of acupressure at the Xiyangguan acupoint (GB33) on the regional oxygen saturation of the deeper knee tissues by near-infrared spectroscopy (NIRS). Twelve healthy volunteers with a mean age of 23.8 ± 1.6 years were investigated. Acupressure stimulation was performed for...

  13. Simultaneous multi-depth assessment of tissue oxygen saturation in thenar and forearm using near-infrared spectroscopy during a simple cardiovascular challenge

    OpenAIRE

    Bezemer, R.; Karemaker, J. M.; Klijn, E; D. Martin; Mitchell, K; Grocott, M.; Heger, M; Ince, C.

    2009-01-01

    INTRODUCTION: Hypovolemia and hypovolemic shock are life-threatening conditions that occur in numerous clinical scenarios. Near-infrared spectroscopy (NIRS) has been widely explored, successfully and unsuccessfully, in an attempt to use it as an early detector of hypovolemia by measuring tissue oxygen saturation (StO2). In order to investigate the measurement site dependence and probe dependence of NIRS in response to hemodynamic changes, such as hypovolemia, we applied a simple cardiovascula...

  14. Predicting Blood Lactate Concentration and Oxygen Uptake from sEMG Data during Fatiguing Cycling Exercise

    Directory of Open Access Journals (Sweden)

    Petras Ražanskas

    2015-08-01

    Full Text Available This article presents a study of the relationship between electromyographic (EMG signals from vastus lateralis, rectus femoris, biceps femoris and semitendinosus muscles, collected during fatiguing cycling exercises, and other physiological measurements, such as blood lactate concentration and oxygen consumption. In contrast to the usual practice of picking one particular characteristic of the signal, e.g., the median or mean frequency, multiple variables were used to obtain a thorough characterization of EMG signals in the spectral domain. Based on these variables, linear and non-linear (random forest models were built to predict blood lactate concentration and oxygen consumption. The results showed that mean and median frequencies are sub-optimal choices for predicting these physiological quantities in dynamic exercises, as they did not exhibit significant changes over the course of our protocol and only weakly correlated with blood lactate concentration or oxygen uptake. Instead, the root mean square of the original signal and backward difference, as well as parameters describing the tails of the EMG power distribution were the most important variables for these models. Coefficients of determination ranging from R2 = 0:77 to R2 = 0:98 (for blood lactate and from R2 = 0:81 to R2 = 0:97 (for oxygen uptake were obtained when using random forest regressors.

  15. Advances of blood oxygen-level dependent MRI in muscular system

    International Nuclear Information System (INIS)

    BOLD-fMRI has been applied to muscular system to observe muscular pathophysiological change after performing a task and show the characteristics of muscle perfusion. This paper mainly introduces the scanning sequence, common tasking methods, such as cuff compression, excise, oxygen and drug, etc. It also introduces clinical study of perfusion reserve of muscular tissue with abnormal blood vessels. (authors)

  16. Effect of Turkish music that premature infants are made to listen during care on stress, oxygen saturation level and length of hospital stay

    Directory of Open Access Journals (Sweden)

    Diler Aydın

    2014-04-01

    Full Text Available Research was planned as an experimental study in order to determine the effect of Turkish music performance applied during care in the neonatal intensive care unit on stress indicators, oxygen saturation, peak heart rate, respiration value and length of hospital stay. It was an experimental study (experimental n: 30; control n: 30. Preterm infants were made to listen Turkish music for 30 minutes every day. Stress indicators, oxygen saturation, peak heart rate and respiration values observed prior to the care and during 30-minute Turkish music session were registered in the Patient Follow-up Form. No significant decrease was observed in the lengths of hospital stay, oxygen saturation levels and stress levels of babies in the experiment and control groups. It was also seen that peak heart rates and respiration values did not vary. As a conclusion, it was determined that Turkish music which preterm babies staying in the neonatal intensive care unit were made to listen did not affect peak heart rates and respiration values statistically significantly and they were normal. It was also seen that stress indicators were not affected.

  17. Near-infrared spectroscopy determined cerebral oxygenation with eliminated skin blood flow in young males

    DEFF Research Database (Denmark)

    Hirasawa, Ai; Kaneko, Takahito; Tanaka, Naoki; Funane, Tsukasa; Kiguchi, Masashi; Sørensen, Henrik; Secher, Niels H; Ogoh, Shigehiko

    2016-01-01

    We estimated cerebral oxygenation during handgrip exercise and a cognitive task using an algorithm that eliminates the influence of skin blood flow (SkBF) on the near-infrared spectroscopy (NIRS) signal. The algorithm involves a subtraction method to develop a correction factor for each subject......-detector distances (15 and 30 mm) with the algorithm using the individual correction factor, we expressed cerebral oxygenation without influence from scalp and scull blood flow. Validity of the estimated cerebral oxygenation was verified during cerebral neural activation (handgrip exercise and cognitive task). With...... pressure was applied to the temporal artery, estimated O2Hb was not affected by elimination of SkBF during handgrip exercise (P = 0.666) or the cognitive task (P = 0.105). These findings suggest that the algorithm with the individual correction factor allows for evaluation of changes in an accurate...

  18. Low FEV1, smoking history, and obesity are factors associated with oxygen saturation decrease in an adult population cohort

    Directory of Open Access Journals (Sweden)

    Vold ML

    2014-10-01

    Full Text Available Monica Linea Vold,1,3 Ulf Aasebø,1,2 Hasse Melbye3 1Department of Respiratory Medicine, University Hospital of North Norway, 2Department of Clinical Medicine, 3Department of Community Medicine, University of Tromsø, Tromsø, Norway Background: Worsening of pulmonary diseases is associated with a decrease in oxygen saturation (SpO2. Such a decrease in SpO2 and associated factors has not been previously evaluated in a general adult population. Aim: We sought to describe SpO2 in a sample of adults, at baseline and after 6.3 years, to determine whether factors predicting low SpO2 in a cross-sectional study were also associated with a decrease in SpO2 in this cohort. Methods: As part of the Tromsø Study, 2,822 participants were examined with pulse oximetry in Tromsø 5 (2001/2002 and Tromsø 6 (2007/2008. Low SpO2 by pulse oximetry was defined as an SpO2 ≤95%, and SpO2 decrease was defined as a ≥2% decrease from baseline to below 96%. Results: A total of 139 (4.9% subjects had a decrease in SpO2. Forced expiratory volume in 1 second (FEV1 <50% of the predicted value and current smoking with a history of ≥10 pack-years were the baseline characteristics most strongly associated with an SpO2 decrease in multivariable logistic regression (odds ratio 3.55 [95% confidence interval (CI 1.60–7.89] and 2.48 [95% CI 1.48–4.15], respectively. Male sex, age, former smoking with a history of ≥10 pack-years, body mass index ≥30 kg/m2, and C-reactive protein ≥5 mg/L were also significantly associated with an SpO2 decrease. A significant decrease in FEV1 and a new diagnosis of asthma or chronic obstructive pulmonary disease during the observation period most strongly predicted a fall in SpO2. A lower SpO2 decrease was observed in those who quit smoking and those who lost weight, but these tendencies were not statistically significant. Conclusion: A decrease in SpO2 was most strongly associated with severe airflow limitation and a history of

  19. Alteration of blood glucose levels in the rat following exposure to hyperbaric oxygen.

    Science.gov (United States)

    Eynan, Mirit; Mullokandov, Michael; Krinsky, Nitzan; Biram, Adi; Arieli, Yehuda

    2015-09-01

    Findings regarding blood glucose level (BGL) on exposure to hyperbaric oxygen (HBO) are contradictory. We investigated the influence of HBO on BGL, and of BGL on latency to central nervous system oxygen toxicity (CNS-OT). The study was conducted on five groups of rats: Group 1, exposure to oxygen at 2.5 atmospheres absolute (ATA), 90 min/day for 7 days; Group 2, exposure to oxygen once a week from 2 to 6 ATA in increments of 1 ATA/wk, for a period of time calculated as 60% of the latency to CNS-OT (no convulsions); Group 3, exposure to 6 ATA breathing a gas mixture with a pO2 of 0.21; Group 4, received 10 U/kg insulin to induce hypoglycemia before exposure to HBO; Group 5, received 33% glucose to induce hyperglycemia before exposure to HBO. Blood samples were drawn before and after exposures for measurement of BGL. No change was observed in BGL after exposure to oxygen at 2.5 ATA, 90 min/day for 7 days. BGL was significantly elevated after exposure to oxygen at 6 ATA until the appearance of convulsions, and following exposure to 4, 5, and 6 ATA without convulsions (P HBO exposure on elevation of BGL, starting at 4 ATA. This implies that BGL may serve as a marker for the generation of CNS-OT. PMID:26183474

  20. Blood gas analyzer utility in evaluating oxygen kinetics of the aqueous humor

    Directory of Open Access Journals (Sweden)

    Ismail Ersan

    2015-04-01

    Full Text Available Purpose: To measure the partial pressure of oxygen (PO2 and carbon dioxide (PCO2 and the pH of aqueous humor (AH and arterial blood samples from rabbits using a blood gas analyzer. Methods: Twenty New Zealand rabbits were anesthetized intramuscularly with ketamine and xylazine and were then allowed to breathe room air. Using a gas blood analyzer, arterial blood and AH samples were analyzed for PO2, PCO2, and pH. Results: The mean arterial blood pressure was 87.14 ± 15.0 mmHg. The mean blood and AH PO2 were 95.18 ± 11.76 mmHg and 88.83 ± 9.92 mmHg, the mean blood and AH PCO2 were 25.86 ± 5.46 mmHg and 29.50 ± 5.36 mmHg, and the mean blood and AH pH were 7.38 ± 0.06 and 7.33 ± 0.09, respectively. Conclusion: Conclusions: The blood gas analyzer was easily employed to evaluate the aqueous humor in rabbits. When comparing the results of studies evaluating aqueous PO2, care should be taken to determine the methods used in these studies.

  1. Enhanced production of nitric oxide, reactive oxygen species, and pro-inflammatory cytokines in very long chain saturated fatty acid-accumulated macrophages

    OpenAIRE

    Kiyanagi Takashi; Sumiyoshi Katsuhiko; Kitamura Yohei; Kume Atsumi; Miyazaki Tetsuro; Shimada Kazunori; Yanagisawa Naotake; Iesaki Takafumi; Inoue Nao; Daida Hiroyuki

    2008-01-01

    Abstract Background Deterioration of peroxisomal β-oxidation activity causes an accumulation of very long chain saturated fatty acids (VLCSFA) in various organs. We have recently reported that the levels of VLCSFA in the plasma and/or membranes of blood cells were significantly higher in patients with metabolic syndrome and in patients with coronary artery disease than the controls. The aim of the present study is to investigate the effect of VLCSFA accumulation on inflammatory and oxidative ...

  2. Blood flow and muscle oxygenation during low, moderate, and maximal sustained isometric contractions.

    Science.gov (United States)

    McNeil, Chris J; Allen, Matti D; Olympico, Eric; Shoemaker, J Kevin; Rice, Charles L

    2015-09-01

    A reduction of blood flow to active muscle will precipitate fatigue, and sustained isometric contractions produce intramuscular and compartmental pressures that can limit flow. The present study explored how blood flow and muscle oxygenation respond to isometric contractions at low, moderate, and maximal intensities. Over two visits, 10 males (26 ± 2 yr; means ± SD) performed 1-min dorsiflexion contractions at 30, 60, and 100% of maximal voluntary contraction (MVC) torque. Doppler ultrasound of the anterior tibial artery was used to record arterial diameter and mean blood velocity and to calculate absolute blood flow. The tissue oxygenation index (TOI) of tibialis anterior was acquired with near-infrared spectroscopy (NIRS). There was a progressive increase in blood flow at 30% MVC (peak of 289 ± 139% resting value), no change from rest until an increase in the final 10 s of exercise at 60% MVC (peak of 197 ± 102% rest), and an initial decrease (59 ± 30% resting value) followed by a progressive increase at 100% MVC (peak of 355 ± 133% rest). Blood flow was greater at 30 and 100% than 60% MVC during the last 30 s of exercise. TOI was ∼63% at rest and, within 30 s of exercise, reached steady-state values of ∼42%, ∼22%, and ∼22% for 30, 60, and 100% MVC, respectively. Even maximal contraction of the dorsiflexors is unable to cause more than a transient decrease of flow in the anterior tibial artery. Unlike dynamic or intermittent isometric exercise, our results indicate blood flow is not linearly graded with intensity or directly coupled with oxygenation during sustained isometric contractions. PMID:26084698

  3. Effects of anesthetic agents on brain blood oxygenation level revealed with ultra-high field MRI.

    Directory of Open Access Journals (Sweden)

    Luisa Ciobanu

    Full Text Available During general anesthesia it is crucial to control systemic hemodynamics and oxygenation levels. However, anesthetic agents can affect cerebral hemodynamics and metabolism in a drug-dependent manner, while systemic hemodynamics is stable. Brain-wide monitoring of this effect remains highly challenging. Because T(2*-weighted imaging at ultra-high magnetic field strengths benefits from a dramatic increase in contrast to noise ratio, we hypothesized that it could monitor anesthesia effects on brain blood oxygenation. We scanned rat brains at 7T and 17.2T under general anesthesia using different anesthetics (isoflurane, ketamine-xylazine, medetomidine. We showed that the brain/vessels contrast in T(2*-weighted images at 17.2T varied directly according to the applied pharmacological anesthetic agent, a phenomenon that was visible, but to a much smaller extent at 7T. This variation is in agreement with the mechanism of action of these agents. These data demonstrate that preclinical ultra-high field MRI can monitor the effects of a given drug on brain blood oxygenation level in the absence of systemic blood oxygenation changes and of any neural stimulation.

  4. Membrane oxygenator heat exchanger failure detected by unique blood gas findings.

    Science.gov (United States)

    Hawkins, Justin L

    2014-03-01

    Failure of components integrated into the cardiopulmonary bypass circuit, although rare, can bring about catastrophic results. One of these components is the heat exchanger of the membrane oxygenator. In this compartment, unsterile water from the heater cooler device is separated from the sterile blood by stainless steel, aluminum, or by polyurethane. These areas are glued or welded to keep the two compartments separate, maintaining sterility of the blood. Although quality control testing is performed by the manufacturer at the factory level, transport presents the real possibility for damage. Because of this, each manufacturer has included in the instructions for use a testing procedure for testing the integrity of the heat exchanger component. Water is circulated through the heat exchanger before priming and a visible check is made of the oxygenator bundle to check for leaks. If none are apparent, then priming of the oxygenator is performed. In this particular case, this procedure was not useful in detecting communication between the water and blood chambers of the oxygenator. PMID:24779125

  5. Near-infrared spectroscopy determined cerebral oxygenation with eliminated skin blood flow in young males.

    Science.gov (United States)

    Hirasawa, Ai; Kaneko, Takahito; Tanaka, Naoki; Funane, Tsukasa; Kiguchi, Masashi; Sørensen, Henrik; Secher, Niels H; Ogoh, Shigehiko

    2016-04-01

    We estimated cerebral oxygenation during handgrip exercise and a cognitive task using an algorithm that eliminates the influence of skin blood flow (SkBF) on the near-infrared spectroscopy (NIRS) signal. The algorithm involves a subtraction method to develop a correction factor for each subject. For twelve male volunteers (age 21 ± 1 yrs) +80 mmHg pressure was applied over the left temporal artery for 30 s by a custom-made headband cuff to calculate an individual correction factor. From the NIRS-determined ipsilateral cerebral oxyhemoglobin concentration (O2Hb) at two source-detector distances (15 and 30 mm) with the algorithm using the individual correction factor, we expressed cerebral oxygenation without influence from scalp and scull blood flow. Validity of the estimated cerebral oxygenation was verified during cerebral neural activation (handgrip exercise and cognitive task). With the use of both source-detector distances, handgrip exercise and a cognitive task increased O2Hb (P cognitive task (P = 0.105). These findings suggest that the algorithm with the individual correction factor allows for evaluation of changes in an accurate cerebral oxygenation without influence of extracranial blood flow by NIRS applied to the forehead. PMID:26018458

  6. Experimental study on therapy of ultraviolet blood irradiation and oxygenation in acute soman intoxication in rabbits

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-qing; MU Shi-jie; ZHANG Xiao-di; CHEN Rui; XIA Ai-jun; LIANG Xin; HAI Chun-xu

    2005-01-01

    Objective: To study the therapy effect of ultraviolet blood irradiation and oxygenation(UBIO) on blood AChe activity and lung injury due to acute soman intoxication in rabbits. Methods :Forty rabbits were randomly divided into 4 groups: normal control group, intoxication group, routine therapy group and UBIO therapy group. Blood AChe activity and artery blood gas were analyzed 2 h after intoxication. ACP and AKP activities in BALF were determined respectively. Results:Blood AChe activity in intoxication group was lower than that in normal control group (P<0. 05). BALF ACP and AKP activities in intoxication group were higher than that in normal control group. Blood AChe activities in UBIO therapy group increased and were higher than that in intoxication and routine therapy groups. Compared with intoxication group, BALF ACP and AKP activities were decreased (P<0.05) in UBIO therapy group,while artery blood pH, PaO2 and SaO2 increased (P<0.05). Conclusion: UBIO therapy can elevate blood AChe activity and alleviate lung injury induced by soman intoxication. So it may be a new way to treat acute soman intoxication.

  7. Investigating the impact of oxygen concentration and blood flow variation on photodynamic therapy

    Science.gov (United States)

    Penjweini, Rozhin; Kim, Michele M.; Finlay, Jarod C.; Zhu, Timothy C.

    2016-03-01

    Type II photodynamic therapy (PDT) is used for cancer treatment based on the combined action of a photosensitizer, a special wavelength of light, oxygen (3O2) and generation of singlet oxygen (1O2). Intra-patient and inter-patient variability of oxygen concentration ([3O2]) before and after the treatment as well as photosensitizer concentration and hemodynamic parameters such as blood flow during PDT has been reported. Simulation of these variations is valuable, as it would be a means for the rapid assessment of treatment effect. A mathematical model has been previously developed to incorporate the diffusion equation for light transport in tissue and the macroscopic kinetic equations for simulation of [3O2], photosensitizers in ground and triplet states and concentration of the reacted singlet oxygen ([1O₂]rx) during PDT. In this study, the finite-element based calculation of the macroscopic kinetic equations is done for 2-(1- Hexyloxyethyl)-2-devinyl pyropheophorbide (HPPH)-mediated PDT by incorporating the information of the photosensitizer photochemical parameters as well as the tissue optical properties, photosensitizer concentration, initial oxygen concentration ([3O2]0), blood flow changes and Φ that have been measured in mice bearing radiation-induced fibrosarcoma (RIF) tumors. Then, [1O2]rx calculated by using the measured [3O2] during the PDT is compared with [1O2]rx calculated based on the simulated [3O₂]; both calculations showed a reasonably good agreement. Moreover, the impacts of the blood flow changes and [3O2]0 on [1O2]rx have been investigated, which showed no pronounced effect of the blood flow changes on the long-term 1O2 generation. When [3O2]0 becomes limiting, small changes in [3O₂] have large effects on [1O2]rx.

  8. Red blood cell aggregation, aggregate strength and oxygen transport potential of blood are abnormal in both homozygous sickle cell anemia and sickle-hemoglobin C disease

    OpenAIRE

    Tripette, Julien; Alexy, Tamas; Hardy-Dessources, Marie-Dominique; Mougenel, Daniele; Beltan, Eric; Chalabi, Tawfik; Chout, Roger; Etienne-Julan, Maryse; Hue, Olivier; Meiselman, Herbert J.; Connes, Philippe

    2009-01-01

    Recent evidence suggests that red cell aggregation and the ratio of hematocrit to blood viscosity, an index of the oxygen transport potential of blood, might considerably modulate blood flow dynamics in the microcirculation. The findings of this study indicate that patients with sickle cell disease and those with sickle cell hemoglobin C disease have low ratios of hematocrit to blood viscosity as compared to normal controls. This may play a role in tissue hypoxia and clinical status of these ...

  9. The influence of ultraviolet blood irradiation and oxygenation on oxygen free radicals metabolism in rabbits with soman intoxication

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective: To investigate the effect of ultraviolet blood irradiation and oxygenation (UBIO) on the metabolism of oxygen free radicals in rabbits with acute soman intoxication. Methods: One hundred rabbits were randomly divided into 5 groups: normal control group, intoxication group, routine therapy group, UBIO therapy group and combined therapy group. After 14 d, the concentration of malondiadehyde (MDA) and activity of superoxide dismutase (SOD), glutathionperoxidase (GSH-Px), catalase (CAT)and total antioxidative capacity (T-AOC) in serum were determined respectively. Results: Compared with the normal control group, the concentration of MDA and activity of CAT in the intoxication group were significantly higher (P < 0. 05 ), but SOD, GSH-Px activity and T-AOC were significantly lower (P<0.05). After UBIO or combined therapy, serum MDA level was significantly lower in comparison with intoxication group (P<0.05), but the activity of SOD, GSH-Px, CAT and T AOC were higher than intoxication group(P<0.05). Conclusion: There is an obvious oxygen free radical injury in rabbits with acute soman intoxication. UBIO can improve the antioxidation ability of rabbits and may be applied to treat acute soman intoxication as adjunctive therapy.

  10. Transcutaneous partial oxygen tension and skin blood flow monitoring: Continuous, noninvasive measures of cardiorespiratory change

    OpenAIRE

    Mark W. Greenlee; Akita, M.

    1985-01-01

    Transcutaneous partial oxygen tension (tc pO₂) and skin blood flow (via heat clearance) were measured noninvasively in 22 male subjects who performed stress-inducing tasks (i.e. hand-grip exercise, cold pressor test, breath holding, hyperventilation and mirror-tracing). An analysis of variance and covariance was conducted for tc pO₂ heat clearance, heart rate, respiration rate, finger pulse volume and systolic/diastolic blood pressure. Results indicate that tc pO₂ can depict phasic cardioresp...

  11. Hepatic encephalopathy is associated with decreased cerebral oxygen metabolism and blood flow, not increased ammonia uptake

    DEFF Research Database (Denmark)

    Dam, Gitte; Keiding, Susanne; Munk, Ole L;

    2013-01-01

    tomography (PET)/computed tomography (CT). Ten patients with cirrhosis were studied during an acute episode of HE; nine were reexamined after recovery. Nine patients with cirrhosis with no history of HE served as controls. Mean CMRO(2) increased from 0.73 µmol oxygen/mL brain tissue/min during HE to 0.......91 µmol oxygen/mL brain tissue/min after recovery (paired t test; P <0.05). Mean CBF increased from 0.28 mL blood/mL brain tissue/min during HE to 0.38 mL blood/mL brain tissue/min after recovery (P <0.05). After recovery from HE, CMRO(2) and CBF were not significantly different from values in the control...

  12. Comparison of oxygen saturation levels in patients receiving Technegas by the conventional unassisted method vs. the positive ventilation delivery system (PVDS)

    International Nuclear Information System (INIS)

    Full text: The purpose of this study is to compare oxygen saturation levels (SaO2) in 289 patients undergoing conventional lung ventilation scintigraphy (control group) and 27 patients undergoing Positive Ventilation Delivery System (PVDS). The 27 patients where selected as their conventional method of inhalation proved to be inadequate or non-diagnostic. The patients underwent a second ventilation using PVDS, which improved the diagnostic quality of the ventilation image and assisted in clinical management decisions. Some patients in both the PVDS and the control group experienced a transient lowering in their SaO2. The mean initial SaO2 in the control group did not fall below 94.9% and in the PVDS group measured 90.6%. 93% (25/27) of patients in the PVDS group were assessed as non CO2 retaining, and received oxygen at 10L/min during Technegas inhalation. The mean trough saturation in the PVDS group was 91.7% which was significantly higher than that of the control group (86.9%). No patient in either group experienced any significant complication attributed to the transient tall in SaO2 during technegas administration. We conclude that oxygen supplied as part of the PVDS system ameliorates the transient reduction in SaO2 seen during standard Technegas administration. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  13. Linear coupling between cerebral blood flow and oxygen consumption in activated human cortex

    OpenAIRE

    Richard D. Hoge; Atkinson, Jeff; Gill, Brad; Crelier, Gérard R.; Marrett, Sean; Pike, G Bruce

    1999-01-01

    The aim of this study was to test the hypothesis that, within a specific cortical unit, fractional changes in cerebral blood flow (CBF) and cerebral metabolic rate of oxygen consumption (CMRO2) are coupled through an invariant relationship during physiological stimulation. This aim was achieved by simultaneously measuring relative changes in these quantities in human primary visual cortex (V1) during graded stimulation with patterns designed to selectively activate different populations of V1...

  14. Effects of Therapeutic Ultrasound on Intramuscular Blood Circulation and Oxygen Dynamics

    OpenAIRE

    Morishita, Katsuyuki; Karasuno, Hiroshi; Yokoi, Yuka; Morozumi, Kazunori; Ogihara, Hisayoshi; Ito, Toshikazu; Fujiwara, Takayuki; Fujimoto, Tetsuya; Abe, Koji

    2014-01-01

    Purpose: This study aimed to clarify the effects of therapeutic ultrasound on intramuscular local blood circulation (and oxygen dynamics) using near-infrared spectroscopy (NIRS). Participants: The participants were 11 healthy males. Methods: All participants performed all three trials; (1) the ultrasound (US group), (2) without powered ultrasound (placebo group), and (3) rest (control group). Ultrasound was applied at 3 MHz, 1.0 W/cm2, and 100% duty cycle for 10 minutes. Evaluation index were...

  15. Red blood cell (RBC) deformability, RBC aggregability and tissue oxygenation in hypertension.

    Science.gov (United States)

    Cicco, G; Pirrelli, A

    1999-01-01

    Arterial hypertension could be considered a progressive ischaemic syndrome interesting the macro and the microcirculation. In order to improve the clinical and therapeutic approach to the treatment of arterial hypertension, research has centered on blood flow to evaluate the different components and their very intricate relationships influencing the micro- and the macrocirculation. Of course the main problem is to study the link between the blood flow and the peripheral tissue oxygenation. During hypertension very important alterations in rheological, mechanical and biochemical characteristics of erythrocytes and of blood flow have been shown. It is very relevant the increase in blood viscosity, the decrease in red blood cell (RBC) deformability, the formation of RBC "rouleaux" and RBC aggregates. These hemorheological determinants can favour an increase of peripheral resistances and of arterial blood pressure, causing or worsening hypertension, a decrease in oxygen transport to tissue and peripheral perfusion, a decrease of the active exchange surface area in the microvasculature, especially in complicated hypertension. We have studied 320 patients: 123 with Essential Hypertension (EH) (M 59, F 64 aged 50 +/- 25 years); 81 with Secondary Hypertension (SH) without associated other pathologies influencing hemorheology (M 42, F 39 aged 48 +/- 20 years); 116 SH with other pathologies or conditions associated influencing hemorheology such as: diabetes, lipoidoproteinosis, obesity, smoking, HD, elderly, etc. (M 48, F 68 aged 46 +/- 20 years). Using a Laser-assisted Optical Rotational Red Cell Analyzer (LORCA) acc. to Hardeman (1994) we studied Elongation Index (EI) and aggregation kinetics of red blood cells in these patients. We also evaluated TcpO2 and TcpCO2 using a transcutaneous oxymeter (Microgas 7650, Kontron Instruments). In hypertensives we found a decrease in erythrocyte deformability (evaluated with EI), in erythrocyte aggregation time, a fibrinogenaemia

  16. Association between minor loading vein architecture and light- and CO2-saturated rates of photosynthetic oxygen evolution among Arabidopsis thaliana ecotypes from different latitudes

    Directory of Open Access Journals (Sweden)

    Christopher M Cohu

    2013-07-01

    Full Text Available Through microscopic analysis of veins and assessment of light- and CO2-saturated rates of photosynthetic oxygen evolution, we investigated the relationship between minor loading vein anatomy and photosynthesis of mature leaves in three ecotypes of Arabidopsis thaliana grown under four different combinations of temperature and photon flux density (PFD. All three ecotypes exhibited greater numbers and cross-sectional area of phloem cells as well as higher photosynthesis rates in response to higher PFD and especially lower temperature. The Swedish ecotype exhibited the strongest response to these conditions, the Italian ecotype the weakest response, and the Col-0 ecotype exhibited an intermediate response. Among all three ecotypes, strong linear relationships were found between light- and CO2-saturated rates of photosynthetic oxygen evolution and the number and area of either sieve elements or of companion and phloem parenchyma cells in foliar minor loading veins, with the Swedish ecotype showing the highest number of cells in minor loading veins (and largest minor veins coupled with unprecedented high rates of photosynthesis. Linear, albeit less significant, relationships were also observed between number and cross-sectional area of tracheids per minor loading vein versus light- and CO2-saturated rates of photosynthetic oxygen evolution. We suggest that sugar distribution infrastructure in the phloem is co-regulated with other features that set the upper limit for photosynthesis. The apparent genetic differences among Arabidopsis ecotypes should allow for future identification of the gene(s involved in augmenting sugar-loading and -transporting phloem cells and maximal rates of photosynthesis.

  17. Meal-induced changes in splanchnic blood flow and oxygen uptake in middle-aged healthy humans

    DEFF Research Database (Denmark)

    Madsen, Jan L; Søndergaard, Susanne B; Møller, Søren

    2006-01-01

    OBJECTIVE: For decades, the determination of changes in splanchnic blood flow and oxygen uptake after a meal has been used in the management of patients with suspected chronic intestinal ischaemia. However, little is known about the normal meal-induced responses. The aim of the present study was...... therefore to measure the splanchnic blood flow and oxygen uptake before and after a standardized meal in a group of middle-aged normal volunteers. MATERIAL AND METHODS: Splanchnic blood flow and oxygen uptake were determined at baseline and after a 3600-kJ mixed meal in 8 healthy women (50-70 years) and 10...

  18. Cerebral blood flow and oxygen metabolism in patients with Parkinson's disease

    International Nuclear Information System (INIS)

    The purpose of this study was to determine functional changes in the cerebral cortex and basal ganglia in Parkinson's disease (PD). Cerebral blood flow (CBF), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2) were determined using 0-15 positron emission tomography in 10 PD patients and five age-matched healthy volunteers. There was a tendency among PD patients towards a decreased CBF and CMRO2 in the cerebral cortex and basal ganglia. These values were significantly lower in the frontal cortex in the PD group than the control group. There was no difference in OEF between the groups. A more decreased cerebral oxygen metabolism was observed in patients staged as severer on the scale of Hoehn and Yahr. There was no correlation between cerebral oxygen metabolism and tremor, rigidity, or bradykinesis. A decreased cerebral oxygen metabolism was associated with mental disorders, such as depression, hallucination, and dementia. These results may provide an important clue for the understanding of mesocortical dopaminergic pathway and the relationship between PD and dementia. (N.K.)

  19. Arterial input function of an optical tracer for dynamic contrast enhanced imaging can be determined from pulse oximetry oxygen saturation measurements

    Science.gov (United States)

    Elliott, Jonathan T.; Wright, Eric A.; Tichauer, Kenneth M.; Diop, Mamadou; Morrison, Laura B.; Pogue, Brian W.; Lee, Ting-Yim; St. Lawrence, Keith

    2012-12-01

    In many cases, kinetic modeling requires that the arterial input function (AIF)—the time-dependent arterial concentration of a tracer—be characterized. A straightforward method to measure the AIF of red and near-infrared optical dyes (e.g., indocyanine green) using a pulse oximeter is presented. The method is motivated by the ubiquity of pulse oximeters used in both preclinical and clinical applications, as well as the gap in currently available technologies to measure AIFs in small animals. The method is based on quantifying the interference that is observed in the derived arterial oxygen saturation (SaO2) following a bolus injection of a light-absorbing dye. In other words, the change in SaO2 can be converted into dye concentration knowing the chromophore-specific extinction coefficients, the true arterial oxygen saturation, and total hemoglobin concentration. A simple error analysis was performed to highlight potential limitations of the approach, and a validation of the method was conducted in rabbits by comparing the pulse oximetry method with the AIF acquired using a pulse dye densitometer. Considering that determining the AIF is required for performing quantitative tracer kinetics, this method provides a flexible tool for measuring the arterial dye concentration that could be used in a variety of applications.

  20. A comparative study of supine lying, side lying and prone positioning on oxygen saturation, in mechanically ventilated patients, in acute respiratory failure

    Directory of Open Access Journals (Sweden)

    Prajakta S. Patil

    2015-07-01

    Methods: Total 33 subjects aged between 15-73 years, 21 male and 12 female patients were selected for study from ICU, Neurological trauma unit Pune. Inclusion criteria: All subjects with respiratory failure due to different pathologies like ARDS, Pulmonary edema, pneumonia, tuberculosis, collection of fluid in pleural cavity with underlying lung collapse. Exclusion criteria: Unstable cardiac conditions, unstable fractures, unstable hemodynamic, recently operated cardiac subjects. The patients were kept in supine position, lateral and prone and vitals like BP, HR, RR and oxygen saturation with help of pulse oximeter noted just before position. Thorough ET or tracheostomy suction was done. Before turning patient if any intercostal drain present was clamped. Results: Paired t-test was used. p values for prone and bilateral side lying positions was < 0.05 showing its significance for above mentioned 3-positions. p value for supine was not < 0.05 showing its non-significance. Conclusion: The study concluded that oxygen saturation improves in prone lying and side lying position as compared to supine lying. But this improvement is quiet significant in prone position as compared to side lying. [Int J Res Med Sci 2015; 3(7.000: 1627-1631

  1. Spatial mapping of blood flow and oxygen consumption in the human calf muscle using near-infrared spectroscopy

    Science.gov (United States)

    Fantini, Sergio; Hoimes, Matthew L.; Casavola, Claudia; Franceschini, Maria-Angela

    2001-05-01

    We have designed a new optical probe to perform spatially resolved measurements of blood flow and oxygen consumption over an area of about 4 x 4 cm2 of the lateral gastrocnemius muscle (calf muscle) of human subjects. The blood flow and the oxygen consumption were measured non- invasively with frequency-domain, near-infrared spectroscopy from the maximum rate of increase of the oxy- and deoxy- hemoglobin concentrations in the muscle during venous occlusion. In a preliminary test on one subject, involving measurements at rest and after exercise, we have found that the spatial variability of the measured blood flow and oxygen consumption is significantly greater than the variability of repeated measurements at a given tissue location. We have also observed a strong spatial dependence of the exercise-induced increase in blood flow and oxygen consumption.

  2. Cerebral blood flow and oxygen metabolism in dementia with Lewy bodies

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Yoshitomo; Takahashi, Satoshi; Yonezawa, Hisashi [Iwate Medical Univ., Morioka (Japan). School of Medicine

    2000-06-01

    Regional cerebral blood flow (rCBF), oxygen metabolism (rCMRO{sub 2}) and the oxygen extraction fraction (rOEF) were measured using the steady-state {sup 15}O technique and positron emission tomography (PET) in six patients with dementia with Lewy bodies (DLB), and compared with ten patients with Alzheimer disease (AD) and six normal controls. In the AD patients, rCBF and rCMRO{sub 2} were significantly decreased in the frontal, parietal, and temporal cortices compared with controls. In DLB patients, rCBF and rCMRO{sub 2} were decreased in the frontal, parietal, temporal, and occipital cortices compared with controls, and were decreased more diffusely than in AD patients. rCBF and rCMRO{sub 2} were significantly decreased in occipital cortex compared with AD patients. rOEF was significantly increased in the parieto-temporal cortex in AD patients compared with controls. In DLB patients, rOEF was significantly increased not only in the parieto-temporal cortex but also in the occipital and frontal cortices compared with controls, and was significantly increased in the occipital cortex compared with AD patients. The diffuse reduction of cerebral blood flow and oxygen metabolism including the occipital cortex may be related to visual hallucination and other visuospatial deficits frequently seen in DLB patients. The increase in rOEF may be mainly due to the reduction in the vascular bed associated with decreased activity in the vasodilatory cholinergic system. (author)

  3. Cerebral blood flow and oxygen metabolism in dementia with Lewy bodies

    International Nuclear Information System (INIS)

    Regional cerebral blood flow (rCBF), oxygen metabolism (rCMRO2) and the oxygen extraction fraction (rOEF) were measured using the steady-state 15O technique and positron emission tomography (PET) in six patients with dementia with Lewy bodies (DLB), and compared with ten patients with Alzheimer disease (AD) and six normal controls. In the AD patients, rCBF and rCMRO2 were significantly decreased in the frontal, parietal, and temporal cortices compared with controls. In DLB patients, rCBF and rCMRO2 were decreased in the frontal, parietal, temporal, and occipital cortices compared with controls, and were decreased more diffusely than in AD patients. rCBF and rCMRO2 were significantly decreased in occipital cortex compared with AD patients. rOEF was significantly increased in the parieto-temporal cortex in AD patients compared with controls. In DLB patients, rOEF was significantly increased not only in the parieto-temporal cortex but also in the occipital and frontal cortices compared with controls, and was significantly increased in the occipital cortex compared with AD patients. The diffuse reduction of cerebral blood flow and oxygen metabolism including the occipital cortex may be related to visual hallucination and other visuospatial deficits frequently seen in DLB patients. The increase in rOEF may be mainly due to the reduction in the vascular bed associated with decreased activity in the vasodilatory cholinergic system. (author)

  4. Meal-induced changes in splanchnic blood flow and oxygen uptake in middle-aged healthy humans

    DEFF Research Database (Denmark)

    Madsen, Jan Lysgård; Søndergaard, SB; Møller, Søren

    2006-01-01

    therefore to measure the splanchnic blood flow and oxygen uptake before and after a standardized meal in a group of middle-aged normal volunteers. MATERIAL AND METHODS: Splanchnic blood flow and oxygen uptake were determined at baseline and after a 3600-kJ mixed meal in 8 healthy women (50-70 years) and 10...... in middle-aged healthy humans. Our data may be relevant for the evaluation of corresponding data from patients with suspected chronic intestinal ischaemia....

  5. Coupling of cerebral blood flow and oxygen metabolism is conserved for chromatic and luminance stimuli in human visual cortex

    OpenAIRE

    Leontiev, Oleg; Buracas, Giedrius T.; Liang, Christine; Ances, Beau M.; Perthen, Joanna E.; Shmuel, Amir; Buxton, Richard B.

    2012-01-01

    The ratio of the changes in cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) during brain activation is a critical determinant of the magnitude of the blood oxygenation level dependent (BOLD) response measured with functional magnetic resonance imaging (fMRI). Cytochrome oxidase (CO), a key component of oxidative metabolism in the mitochondria, is non-uniformly distributed in visual area V1 in distinct blob and interblob regions, suggesting significant spatial variation...

  6. Effect of blood oxygenation on light penetration depth in rat kidney: preliminary investigation

    International Nuclear Information System (INIS)

    Assessment of the influence of blood O2 partial pressure on laser light penetration in rat kidney was made in situ. Light emitted from semiconductor laser diodes at near infra-red wavelegths was applied. Changes in O2 partial pressure were induced by allowing the animals to breath gas mixtures of different O2 fractions. The results suggest that O2 partial pressures can influence the extent of light penetration in tissues. Average optical depth of penetration in the wavelength range 775-805 nm has increased by 0.53 mm (28%) when the inspired O2 fraction was 55% compared with normally oxygenated ones. This is attributed to the fact that fully oxygenated blood is more transparent to light in the wavelength range 600 nm to 800 nm than deoxygenated blood in the same wavelength range. The results found in this preliminary work, could be valuable in the phototherapy of either deeply situated tumours or those found in pigmented tissues. (author). 21 refs., 3 figs., 1 table

  7. Simultaneous blood flow and blood oxygenation measurements using a combination of diffuse speckle contrast analysis and near-infrared spectroscopy

    Science.gov (United States)

    Seong, Myeongsu; Phillips, Zephaniah; Mai, Phuong Minh; Yeo, Chaebeom; Song, Cheol; Lee, Kijoon; Kim, Jae Gwan

    2016-02-01

    A combined diffuse speckle contrast analysis (DSCA)-near-infrared spectroscopy (NIRS) system is proposed to simultaneously measure qualitative blood flow and blood oxygenation changes in human tissue. The system employs an optical switch to alternate two laser sources at two different wavelengths and a CCD camera to capture the speckle image. Therefore, an optical density can be measured from two wavelengths for NIRS measurements and a speckle contrast can be calculated for DSCA measurements. In order to validate the system, a flow phantom test and an arm occlusion protocol for arterial and venous occlusion were performed. Shorter exposure times (<1 ms) show a higher drop (between 50% and 66%) and recovery of 1/KS2 values after occlusion (approximately 150%), but longer exposure time (3 ms) shows more consistent hemodynamic changes. For four subjects, the 1/KS2 values dropped to an average of 82.1±4.0% during the occlusion period and the average recovery of 1/KS2 values after occlusion was 109.1±0.8%. There was also an approximately equivalent amplitude change in oxyhemoglobin (OHb) and deoxyhemoglobin (RHb) during arterial occlusion (max RHb=0.0085±0.0024 mM/DPF, min OHb=-0.0057±0.0044 mM/DPF). The sensitivity of the system makes it a suitable modality to observe qualitative hemodynamic trends during induced physiological changes.

  8. Effect of acute and delayed hyperbaric oxygen therapy on cyanide whole blood levels during acute cyanide intoxication

    DEFF Research Database (Denmark)

    Lawson-Smith, P; Jansen, E C; Hilsted, Linda Maria;

    2011-01-01

    causing depletion of adenosine triphosphate. Hyperbaric oxygen (HBO2) is recommended for treating carbon monoxide poisoning. The therapeutic effect is due to a high oxygen pressure removing carbon monoxide from the cells. We hypothesise that HBO2 induces changes in whole-blood-cyanide by a competitive...

  9. Simple exercises that significantly increase cerebral blood flow and cerebral oxygenation

    CERN Document Server

    Gersten, Alexander; Raz, Amir; Fried, Robert

    2011-01-01

    We tested the hypothesis that simple exercises may significantly increase cerebral blood flow (CBF) and/or cerebral oxygenation. Eighteen subjects ranging in age from nineteen to thirty nine participated in a four-stage study during which measurements of end tidal CO_2 (EtCO2 - by capnometer) and local brain oxygenation (by near-infrared spectroscopy (NIRS) sensor) were taken. The four stages were 1) baseline, 2) breathing exercises, 3) solving an arithmetic problem, and 4) biofeedback. During the breathing exercises there was a significant increase in EtCO2 indicating a significant increase in global CBF. The increase in global CBF was estimated on the basis of a theoretical model. During the arithmetic and biofeedback tasks there was a significant increase in the local (Fp1) oxygenation, but it varied between the different participants. The results may lead to new clinical applications of CBF and brain oxygenation monitoring and behavioral control. We foresee future more detailed investigations in the contr...

  10. SU-E-T-326: The Oxygen Saturation (SO2) and Breath-Holding Time Variation Applied Active Breathing Control (ABC)

    International Nuclear Information System (INIS)

    Purpose: To study the oxygen saturation (SO2) and breath-holding time variation applied active breathing control (ABC) in radiotherapy of tumor. Methods: 24 volunteers were involved in our trials, and they all did breath-holding motion assisted by ELEKTA Active Breathing Coordinator 2.0 for 10 times respectively. And the patient monitor was used to observe the oxygen saturation (SO2) variation. The variation of SO2, and length of breath-holding time and the time for recovering to the initial value of SO2 were recorded and analyzed. Results: (1) The volunteers were divided into two groups according to the SO2 variation in breath-holding: A group, 14 cases whose SO2 reduction were more than 2% (initial value was 97% to 99%, while termination value was 91% to 96%); B group, 10 cases were less than 2% in breath-holding without inhaling oxygen. (2) The interfraction breath holding time varied from 8 to 20s for A group compared to the first breath-holding time, and for B group varied from 4 to 14s. (3) The breathing holding time of B group prolonged mean 8s, compared to A group. (4) The time for restoring to the initial value of SO2 was from 10s to 30s. And the breath-holding time shortened obviously for patients whose SO2 did not recover to normal. Conclusion: It is very obvious that the SO2 reduction in breath-holding associated with ABC for partial people. It is necessary to check the SO2 variation in breath training, and enough time should be given to recover SO2

  11. Local cerebral blood flow and local oxygen consumption in prolonged hemiplegic migraine

    International Nuclear Information System (INIS)

    This work gives the results of a study by positron emission tomography of the cerebral blood flow (CBF), oxygen-extraction rate (O2E) and oxygen consumption (CMRO2) during severe and prolonged attack of hemiplegic migraine. The salient facts observed are a high (CBF) in the brain hemisphere affected (ruling out the hypothesis of a persistent cerebral ischemia), together with a collapsed O2E (''luxury perfusion'') and especially preservation of the CMRO2 suggesting a decoupling not only between CBF and CMRO2 but also between CMRO2 and functional state of the tissue. Some time after the attack a new study showed the recoupling between CBF and CMRO2, but with the latter reduced in the affected hemisphere although the clinical and tomodensitometric state had returned to normal. These new observations should not however be improperly generalised to all migraines, given the unusual characteristics of the disorder in our patient

  12. Cerebral oxygen and glucose metabolism and blood flow in mitochondrial encephalomyopathy: a PET study

    International Nuclear Information System (INIS)

    Cerebral blood flow (CBF), oxygen metabolism (CMRO2), and glucose metabolism (CMRGlc) were measured using positron emission tomography in five patients diagnosed as having mitochondrial encephalomyopathy. The molar ratio between the oxygen and glucose consumptions was reduced diffusely, as CMRO2 was markedly decreased and CMRGlc was slightly reduced. The CBF showed less changes. The CBF increase on hypercapnia was smaller than normal, though this was not significant. CBF with hypocapnia demonstrated a significant reduction compared with the normal. These results suggest that oxidative metabolism is impaired and anaerobic glycolysis relatively stimulated, due to a primary defect of mitochondrial function, and that mild lactic acidosis occurs in brain tissue because of impaired utilisation of pyruvate in the TCA cycle. As these findings appear to indicate directly a characteristic of this disease, such measurements may be a useful tool for assessment of the pathophysiology and for diagnosis of mitochondrial encephalomyopathy. (orig.). With 1 fig., 4 tabs

  13. Impaired cerebral blood flow and oxygenation during exercise in type 2 diabetic patients

    DEFF Research Database (Denmark)

    Kim, Yu-Sok; Seifert, Thomas; Brassard, Patrice;

    2015-01-01

    Endothelial vascular function and capacity to increase cardiac output during exercise are impaired in patients with type 2 diabetes (T2DM). We tested the hypothesis that the increase in cerebral blood flow (CBF) during exercise is also blunted and, therefore, that cerebral oxygenation becomes.......05). In contrast, CBF increased ~20% during exercise in the control group while the brain uptake of lactate and glucose was similar in the two groups. In conclusion, these results suggest that impaired CBF and oxygenation responses to exercise in T2DM patients may relate to limited ability to increase cardiac...... affected and perceived exertion increased in T2DM patients. We quantified cerebrovascular besides systemic hemodynamic responses to incremental ergometer cycling exercise in eight male T2DM and seven control subjects. CBF was assessed from the Fick equation and by transcranial Doppler-determined middle...

  14. Modeling of a three-source perfusion and blood oxygenation sensor for transplant monitoring using multilayer Monte Carlo code

    Science.gov (United States)

    Ibey, Bennett L.; Lee, Seungjoon; Ericson, M. Nance; Wilson, Mark A.; Cote, Gerard L.

    2004-06-01

    A Multi-Layer Monte Carlo (MLMC) model was developed to predict the results of in vivo blood perfusion and oxygenation measurement of transplanted organs as measured by an indwelling optical sensor. A sensor has been developed which uses three-source excitation in the red and infrared ranges (660, 810, 940 nm). In vitro data was taken using this sensor by changing the oxygenation state of whole blood and passing it through a single-tube pump system wrapped in bovine liver tissue. The collected data showed that the red signal increased as blood oxygenation increased and infrared signal decreased. The center wavelength of 810 nanometers was shown to be quite indifferent to blood oxygenation change. A model was developed using MLMC code that sampled the wavelength range from 600-1000 nanometers every 6 nanometers. Using scattering and absorption data for blood and liver tissue within this wavelength range, a five-layer model was developed (tissue, clear tubing, blood, clear tubing, tissue). The theoretical data generated from this model was compared to the in vitro data and showed good correlation with changing blood oxygenation.

  15. Challenges in understanding the impact of blood pressure management on cerebral oxygenation in the preterm brain

    Directory of Open Access Journals (Sweden)

    Aminath eAzhan

    2012-12-01

    Full Text Available Systemic hypotension in preterm infants has been related to increased mortality, cerebrovascular lesions and neurodevelopmental morbidity. Treatment of hypotension with inotropic medications aims at preservation of end organ perfusion and oxygen delivery, especially the brain. The common inotropic medications in preterm infants include dopamine, dobutamine, adrenalin, with adjunctive use of corticosteroids in cases of refractory hypotension. Whether maintenance of mean arterial blood pressure (MAP by use of inotropic medication is neuroprotective or not remains unclear. This review explores the different inotropic agents and their effects on perfusion and oxygenation in the preterm brain, in clinical studies as well as in animal models. Dopamine and adrenalin, because of their -adrenergic vasoconstrictor actions, have raised concerns of reduction in cerebral blood flow (CBF. Several studies in hypotensive preterm infants have shown that dopamine elevates CBF together with increased MAP, in keeping with limited cerebro-autoregulation. Adrenaline is also effective in raising cerebral perfusion together with MAP in preterm infants. Experimental studies in immature animals show no cerebro-vasoconstrictive effects of dopamine or adrenaline, but demonstrate the consistent findings of increased cerebral perfusion and oxygenation with the use of dopamine, dobutamine and adrenaline, alongside with raised MAP. Both clinical and animal studies report the transitory effects of adrenaline in increasing plasma lactate, and blood glucose, which might render its use as a 2nd line therapy. To investigate the cerebral effects of inotropic agents in long-term outcome in hypotensive preterm infants, carefully designed prospective research possibly including preterm infants with permissive hypotension is required. Preterm animal models would be useful in investigating the relationship between the physiological effects of inotropes and histopathology outcomes in

  16. How bold is blood oxygenation level dependent (BOLD) magnetic resonance imaging of the kidney? Opportunities, challenges and future directions

    OpenAIRE

    Niendorf, T; Pohlmann, A.; Arakelyan, K.; Flemming, B; Cantow, K.; Hentschel, J.; Grosenick, D; Ladwig, M.; Reimann, H; Klix, S.; Waiczies, S; Seeliger, E.

    2015-01-01

    Renal tissue hypoperfusion and hypoxia are key elements in the pathophysiology of acute kidney injury and its progression to chronic kidney disease. Yet, in vivo assessment of renal haemodynamics and tissue oxygenation remains a challenge. Many of the established approaches are invasive, hence not applicable in humans. Blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) offers an alternative. BOLD-MRI is non-invasive and indicative of renal tissue oxygenation. Nonetheles...

  17. Blood oxygenation level-dependent response to intragastric load of corn oil emulsion in conscious rats.

    Science.gov (United States)

    Tsurugizawa, Tomokazu; Uematsu, Akira; Uneyama, Hisayuki; Torii, Kunio

    2009-12-01

    The postingestive actions after intragastric or oronasal stimulation of fat have been well investigated. The blood oxygenation level-dependent (BOLD) signal changes, however, after intragastric load of corn oil emulsion have yet to be elucidated. Here, using functional magnetic resonance imaging, we investigated the BOLD signal response to gut corn oil emulsion in nonanesthetized rats. Intragastrically infused 7% corn oil emulsion induced a BOLD signal increase in several brain regions, including the bilateral amygdala, hippocampus and the ventral tegmental area. These results indicate that the limbic system responds to gut corn oil emulsion and that activation of this system could promote the reinforcing action for food with high fat content. PMID:19918206

  18. Dynamics of Dissolved Oxygen in Relation to Saturation and Health of an Aquatic Body: A Case for Chilka Lagoon, India

    Directory of Open Access Journals (Sweden)

    B. S. R. V. Prasad

    2014-01-01

    Full Text Available Dissolved oxygen (DO is essential for an aquatic ecosystem since it controls the biological productivity. Here, we propose a unidimensional dynamic model for DO by incorporating biological (photosynthesis, respiration, and mineralization, physical (atmospheric reaeration and chemical (nitrification processes so characteristic of shallow coastal water bodies. The analytical study of the proposed model is focussed on supersaturation and undersaturation of oxygen in the water body. The controllability of the ecosystem health has also been investigated. Model results indicate that, while undersaturation of oxygen is largely governed by nitrification and Net Ecosystem Metabolism (NEM, the supersaturation is controlled by photosynthetic activity. The model results are corroborated with observed data collected from Chilka lagoon, India. Subsequently, a biogeochemical model to study the DO variations in Chilka lagoon has been constructed. The model is properly calibrated and validated with observed data. Two independent sets of data (2004-2005 and 2005-2006 were used for model calibration and validation and Chi-square tests supported its robustness (R2=0.982 and 0.987; P<0.05. The model was used to evaluate independently the influence of individual taxa (diatoms, microphytobenthos, and cyanophyceans on DO variations. Simulations indicate the vital role of microphytobenthos in lagoon DO dynamics and the overall wellbeing.

  19. The dual roles of red blood cells in tissue oxygen delivery

    DEFF Research Database (Denmark)

    Jensen, Frank Bo

    2009-01-01

    Vertebrate red blood cells (RBCs) seem to serve tissue oxygen delivery in two distinct ways. Firstly, RBCs enable the adequate transport of O2 between respiratory surfaces and metabolizing tissues by means of their high intracellular concentration of hemoglobin (Hb), appropriate allosteric...... interactions between Hb ligand-binding sites, and an adjustable intracellular chemical environment that allows fine-tuning of Hb O2 affinity. Secondly, RBCs may sense tissue O2 requirements via their degree of deoxygenation when they travel through the microcirculation and release vasodilatory compounds that...... enhance blood flow in hypoxic tissues. This latter function could be important in matching tissue O2 delivery with local O2 demand. Three main mechanisms by which RBCs can regulate their own distribution in the microcirculation have been proposed. These are: (1) deoxygenation-dependent release of ATP from...

  20. Integrated Measurements of Electrical Activity, Oxygen Tension, Blood Flow, and Ca2+ -Signaling in Rodents In Vivo

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Thomsen, Kirsten; Lauritzen, Martin

    2014-01-01

    in rodent preparation. We also describe methods for recording of cerebral blood flow (CBF), tissue partial pressure of oxygen (tpO2), and cytosolic calcium transients. We finally give examples where electrophysiology, blood flow, metabolism, and calcium transients have been studied together....

  1. EFFECT OF ACUPUNCTURE ON BLOOD OXYGEN FREE RADICAL AND NO LEVELS IN TREATMENT OF APOPLECTIC SEQUELAE

    Institute of Scientific and Technical Information of China (English)

    袁青; 马瑞玲; 靳瑞

    2003-01-01

    Objective: To observe the effect of acupuncture on blood oxygen free radical (OFR) and nitric oxide(NO) levels in the treatment of apoplectic sequelae. Methods: A total of 61 cases of apoplectic patients were subject-ed into this study and randomly divided into "JIN San Zhen" group (n=30) and control group (n=31). Blood lipid per-oxidase (LPO), superoxide dismutase (SOD), glutathione peroxidase(GSH-Px) and nitric oxide (NO) contents beforeand after acupuncture treatment were determined with radioimmunoassay. In both groups, acupuncture was given oncedaily, six times a week, with 4 weeks being a therapeutic course and with the interval between two weeks being aweek, 3 courses all together. In "JIN San Zhen" group, acupoints of "JIN San Zhen" were used predominately, whilein control group, scalp-point Motor Sensory Area (MS 8) was used as the main point. Results: Self-comparison showedthat after 3 courses of treatment, in both groups, LPO and NO levels decreased significantly ( P < 0.05 - 0.01 ), SODand GST-Px values increased considerably ( P< 0.05 - 0.01 ). Comparison between two groups indicated that the ef-fects of "JIN San Zhen" group are significantly superior to those of control group in raising blood SOD and GST-Px lev-els ( P< 0.05- 0.01 ) and in lowering blood NO content ( P< 0.01 ). Analysis on the correlation between the restora-tion of neural function and the changes of LPO, SOD and GST-Px levels suggested that the effect of acupuncture in im-proving neural function may be related to changes of the aforementioned indexes. Conclusion: Acupuncture therapy cansignificantly lower blood LPO and NO levels and evidently raise blood SOD and GST-Px levels in stroke patients.

  2. Diving Related Changes in the Blood Oxygen Stores of Rehabilitating Harbor Seal Pups (Phoca vitulina.

    Directory of Open Access Journals (Sweden)

    Amber Thomas

    Full Text Available Harbor seal (Phoca vitulina pups begin diving within hours of birth, stimulating the development of the blood oxygen (O2 stores necessary to sustain underwater aerobic metabolism. Since harbor seals experience a brief nursing period, the early-life development of these blood O2 stores is necessary for successful post-weaning foraging. If mothers and pups become prematurely separated, the pup may be transported to a wildlife rehabilitation center for care. Previous studies suggest that the shallow pools and lack of diving in rehabilitation facilities may lead to under-developed blood O2 stores, but diving behavior during rehabilitation has not been investigated. This study aimed to simultaneously study the diving behaviors and blood O2 store development of rehabilitating harbor seal pups. Standard hematology measurements (Hct, Hb, RBC, MCV, MCH, MCHC were taken to investigate O2 storage capacity and pups were equipped with time-depth recorders to investigate natural diving behavior while in rehabilitation. Linear mixed models of the data indicate that all measured blood parameters changed with age; however, when compared to literature values for wild harbor seal pups, rehabilitating pups have smaller red blood cells (RBCs that can store less hemoglobin (Hb and subsequently, less O2, potentially limiting their diving capabilities. Wild pups completed longer dives at younger ages (maximum reported <25 days of age: 9 min in previous studies than the captive pups in this study (maximum <25 days of age: 2.86 min. However, captivity may only affect the rate of development, as long duration dives were observed (maximum during rehabilitation: 13.6 min at 89 days of age. Further, this study suggests that there may be a positive relationship between RBC size and the frequency of long duration dives. Thus, rehabilitating harbor seal pups should be encouraged to make frequent, long duration dives to prepare themselves for post-release foraging.

  3. Discriminating between the effect of shunt and reduced VA/Q on arterial oxygen saturation is particularly useful in clinical practice.

    Science.gov (United States)

    Jones, J G; Jones, S E

    2000-01-01

    There is an extensive literature on methods for discriminating between an increased shunt and a reduced ratio of ventilation to perfusion. In this review we prefer the terms "VA/Q" and "reduced or low VA/Q" rather than "V/Q inequality" to refer to the effects on arterial oxygenation of reducing V/Q below 0.8 to about 0.1. Almost without exception the conventional methods for measuring shunt and reduced VA/Q are invasive as well as technically complex. For most clinicians who are dealing with a hypoxemic patient the relevance of these entities is not so obvious as to justify the time and difficulty in either understanding or measuring them. However this review shows that, while an increased shunt and a decreased VA/Q both reduce arterial oxygen saturation (SaO2) at a particular inspired oxygen concentration (PIO2), the effect of shunt and reduced VA/Q have important clinical differences on the relationship between PIO2 and SaO2. The review also outlines a simple non-invasive method for measuring shunt and reduced VA/Q which illustrates the value of discriminating between them in clinical practice. PMID:12580217

  4. Effects of diving and oxygen on autonomic nervous system and cerebral blood flow.

    Science.gov (United States)

    Winklewski, Pawel J; Kot, Jacek; Frydrychowski, Andrzej F; Nuckowska, Magdalena K; Tkachenko, Yurii

    2013-09-01

    Recreational scuba diving is a popular leisure activity with the number of divers reaching several millions worldwide. Scuba diving represents a huge challenge for integrative physiology. In mammalian evolution, physiological reflexes developed to deal with lack of oxygen, rather than with an excess, which makes adaptations to scuba diving more difficult to describe and understand than those associated with breath-hold diving. The underwater environment significantly limits the use of equipment to register the organism's functions, so, in most instances, scientific theories are built on experiments that model real diving to some extent, like hyperbaric exposures, dive reflexes or water immersion. The aim of this review is to summarise the current knowledge related to the influence exerted by physiological conditions specific to diving on the autonomic nervous system and cerebral blood flow. The main factors regulating cerebral blood flow during scuba diving are discussed as follows: 1) increased oxygen partial pressure; 2) immersion-related trigemino-cardiac reflexes and 3) exposure to cold, exercise and stress. Also discussed are the potential mechanisms associated with immersion pulmonary oedema. PMID:24122190

  5. Can we increase hepatic oxygen availability? The role of intentional hypercarbia.

    Science.gov (United States)

    Atallah, M M; Demian, A D; el-Diasty, T A; Ma Saied, M

    2000-06-01

    Our hypothesis is that hypercarbia produces sympathetic stimulant effect and local vasodilatation. We studied the effect of intentional hypercarbia (IHC) on hepatic venous oxygen saturation. The hepatic vein (HV) was cannulated in 15 patients through either the right internal jugular vein or the femoral vein to measure HV oxygen saturation and calculate oxygen content. The inferior vena cava (IVC) was cannulated in 6 patients above and below drainage of the hepatic veins for oxygen saturation and content difference along the IVC. IHC was achieved in awake patients by breathing oxygen enriched air at a flow rate of 2L/min for 10 min, and during anesthesia by increasing anesthetic dead space and reducing tidal volume. IHC increased HV blood oxygen saturation, decreased the arterio-hepatic vein oxygen content difference and decreased oxygen saturation difference and oxygen content difference along IVC. PMID:11126503

  6. Effects of cardiopulmonary bypass on gut blood flow, oxygen utilization, and intramucosal pH.

    Science.gov (United States)

    Ohri, S K; Becket, J; Brannan, J; Keogh, B E; Taylor, K M

    1994-05-01

    Studies documenting rises in endotoxin after cardiopulmonary bypass (CPB) have postulated gut mucosal hypoperfusion. We have investigated alterations in jejunal blood flow by laser Doppler flow measurement, intramucosal pH (pHi) by tonometry, and oxygen utilization in a canine model of hypothermic CPB (n = 11 dogs). After 10 minutes of hypothermic CPB, despite no major reduction in superior mesenteric artery flow, mucosal laser Doppler flow decreased to -38.2% +/- 9.3% of levels obtained before bypass (p = 0.008) and serosal laser Doppler flow, to -47.3% +/- 11.4% (p = 0.006). During the hypothermic phase, mesenteric oxygen consumption fell from 0.18 +/- 0.01 to 0.098 +/- 0.01 mL.min-1.kg-1 (p = 0.005), and mesenteric oxygen delivery fell from 1.97 +/- 0.39 to 1.14 +/- 0.12 mL.min-1.kg-1 (p = 0.05). There was no change in jejunal pHi. During the rewarming phase, there was a substantial increase in mucosal laser Doppler flow, peaking at +69.8% +/- 15.2% (p = 0.03), whereas serosal laser Doppler flow returned to values seen prior to CPB (-16.4% +/- 21.5%; p = 0.25). These changes coincided with a surge in oxygen consumption (0.33 +/- 0.042 mL.min-1.kg-1; p = 0.009), while mesenteric oxygen delivery remained depressed at 1.09 +/- 0.12 mL.min-1.kg-1 (p = 0.04). Jejunal pHi fell from a value of 7.36 +/- 0.04 before CPB to 7.12 +/- 0.07 (p = 0.02), thus indicating mucosal hypoxia. During the rewarming phase of hypothermic CPB, there is a disparity between mesenteric oxygen consumption and oxygen delivery with villus tip ischemia; these findings may explain the pathophysiology of endotoxemia during CPB. PMID:8179384

  7. Improved Apnea-Hypopnea Index and Lowest Oxygen Saturation After Maxillomandibular Advancement With or Without Counterclockwise Rotation in Patients With Obstructive Sleep Apnea

    DEFF Research Database (Denmark)

    Knudsen, Torben B.; Laulund, Anne Sofie; Ingerslev, Janne;

    2015-01-01

    - and postsurgical values of pharyngeal volume measured on computed tomogram or cone-beam computed tomogram and changes in Apnea-Hypopnea Index (AHI) and lowest oxygen saturation (LSAT) values after surgery. Datawere subjected to a meta-analysis based on odds ratios (OR) with 95% confidence intervals...... correlation between pharyngeal volume changes and surgical method used. Postoperative parameters included an AHI lower than 5 (OR = 14.9; 95% CI, 2.7-83.5; P = .002), an AHI lower than 20 (OR = 114.8; 95% CI, 23.5-561.1; P <.00001), pooled results of a 50% decrease in the AHI (OR = 6.1; 95% CI, 2.2-17.0; P...

  8. Carboxylated nanodiamond and re-oxygenation process of gamma irradiated red blood cells

    Energy Technology Data Exchange (ETDEWEB)

    Acosta-Elias, M. [Doctorado en Nanotecnologia, Universidad de Sonora (Mexico); Sarabia-Sainz, A.; Silva-Campa, E.; Angulo-Molina, A.; Soto-Puebla, D.; Barboza-Flores, M.; Melendrez, R.; Alvarez-Garcia, S.; Pedroza-Montero, M. [Departamento de Investigacion en Fisica, Universidad de Sonora, Hermosillo (Mexico); Pedroso-Santana, S. [Doctorado en Ciencias (Fisica), Universidad de Sonora, Hermosillo (Mexico); Santacruz-Gomez, K.; Castaneda, B. [Departamento de Fisica, Universidad de Sonora, Hermosillo (Mexico)

    2015-11-15

    Nanodiamonds (NDs) possess exceptional physical, chemical, and biological properties, which make them suitable for potential biomedical applications. They are biocompatible and their usefulness as effective Raman/fluorescence probes for labeling as well as for drug delivery has been demonstrated. Related to their biocompatibility, the interaction between NDs and red blood cells (RBCs) is of great interest. In this work, the influence of carboxylated NDs (cNDs) in the re-oxygenation capability of both γ-irradiated and stored RBCs was studied. The standard 25 Gy γ dose recommended to prevent transfusion associated graft-versus-host disease was used. A 5-day maximum storage time was used to evaluate the ''storage lesion''. The hemoglobin (Hb) oxygenation state was assessed by Raman microspectroscopy and the morphologic changes on cells were tracked by optical imaging. Our results show that irradiated RBCs have a better re-oxygenation capability and morphological recovery when they are in presence of cNDs. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Vitamin D Depletion in Pregnancy Decreases Survival Time, Oxygen Saturation, Lung Weight and Body Weight in Preterm Rat Offspring.

    Science.gov (United States)

    Lykkedegn, Sine; Sorensen, Grith Lykke; Beck-Nielsen, Signe Sparre; Pilecki, Bartosz; Duelund, Lars; Marcussen, Niels; Christesen, Henrik Thybo

    2016-01-01

    Animal studies suggest a role of vitamin D in fetal lung development although not studied in preterm animals. We tested the hypothesis that vitamin D depletion aggravates respiratory insufficiency in preterm rat offspring. Furthermore, the effects of vitamin D depletion on growth and lung surfactant were investigated. Female Sprague-Dawley rats were randomly assigned low vitamin D (VDL) or control diet before mating and followed with serum 25-hydroxyvitamin D (s-25(OH)D) determinations. After cesarean section at gestational day 19 (E19) or day 22 (E22), placental weight, birth weight, crown-rump-length (CRL), oxygenation (SaO2) at 30 min and survival time were recorded. The pup lungs were analyzed for phospholipid levels, surfactant protein A-D mRNA and the expression of the vitamin D receptor (VDR). S-25(OH)D was significantly lower in the VDL group at cesarean section (12 vs. 30nmol/L, p<0.0001). Compared to the controls, E19 VDL pups had lower birth weight (2.13 vs. 2.29g, p<0.001), lung weight (0.09 vs. 0.10g, p = 0.002), SaO2 (54% vs. 69%, p = 0.002) as well as reduced survival time (0.50 vs. 1.25h, p<0.0001). At E22, the VDL-induced pulmonary differences were leveled out, but VDL pups had lower CRL (4.0 vs. 4.5cm, p<0.0001). The phospholipid levels and the surfactant protein mRNA expression did not differ between the dietary groups. In conclusion, Vitamin D depletion led to lower oxygenation and reduced survival time in the preterm offspring, associated with reduced lung weight and birth weight. Further studies of vitamin D depletion in respiratory insufficiency in preterm neonates are warranted. PMID:27571350

  10. Global brain blood-oxygen level responses to autonomic challenges in obstructive sleep apnea.

    Directory of Open Access Journals (Sweden)

    Paul M Macey

    Full Text Available Obstructive sleep apnea (OSA is accompanied by brain injury, perhaps resulting from apnea-related hypoxia or periods of impaired cerebral perfusion. Perfusion changes can be determined indirectly by evaluation of cerebral blood volume and oxygenation alterations, which can be measured rapidly and non-invasively with the global blood oxygen level dependent (BOLD signal, a magnetic resonance imaging procedure. We assessed acute BOLD responses in OSA subjects to pressor challenges that elicit cerebral blood flow changes, using a two-group comparative design with healthy subjects as a reference. We separately assessed female and male patterns, since OSA characteristics and brain injury differ between sexes. We studied 94 subjects, 37 with newly-diagnosed, untreated OSA (6 female (age mean ± std: 52.1±8.1 yrs; apnea/hypopnea index [AHI]: 27.7±15.6 events/hr and 31 male 54.3±8.4 yrs; AHI: 37.4±19.6 events/hr, and 20 female (age 50.5±8.1 yrs and 37 male (age 45.6±9.2 yrs healthy control subjects. We measured brain BOLD responses every 2 s while subjects underwent cold pressor, hand grip, and Valsalva maneuver challenges. The global BOLD signal rapidly changed after the first 2 s of each challenge, and differed in magnitude between groups to two challenges (cold pressor, hand grip, but not to the Valsalva maneuver (repeated measures ANOVA, p<0.05. OSA females showed greater differences from males in response magnitude and pattern, relative to healthy counterparts. Cold pressor BOLD signal increases (mean ± adjusted standard error at the 8 s peak were: OSA 0.14±0.08% vs. Control 0.31±0.06%, and hand grip at 6 s were: OSA 0.08±0.03% vs. Control at 0.30±0.02%. These findings, indicative of reduced cerebral blood flow changes to autonomic challenges in OSA, complement earlier reports of altered resting blood flow and reduced cerebral artery responsiveness. Females are more affected than males, an outcome which may contribute to the sex

  11. Slowed muscle oxygen uptake kinetics with raised metabolism are not dependent on blood flow or recruitment dynamics.

    Science.gov (United States)

    Wüst, Rob C I; McDonald, James R; Sun, Yi; Ferguson, Brian S; Rogatzki, Matthew J; Spires, Jessica; Kowalchuk, John M; Gladden, L Bruce; Rossiter, Harry B

    2014-04-15

    Oxygen uptake kinetics (τVO2) are slowed when exercise is initiated from a raised metabolic rate. Whether this reflects the recruitment of muscle fibres differing in oxidative capacity, or slowed blood flow (Q) kinetics is unclear. This study determined τVO2 in canine muscle in situ, with experimental control over muscle activation and Q during contractions initiated from rest and a raised metabolic rate. The gastrocnemius complex of nine anaesthetised, ventilated dogs was isolated and attached to a force transducer. Isometric tetanic contractions (50 Hz; 200 ms duration) via supramaximal sciatic nerve stimulation were used to manipulate metabolic rate: 3 min stimulation at 0.33 Hz (S1), followed by 3 min at 0.67 Hz (S2). Circulation was initially intact (SPON), and subsequently isolated for pump-perfusion (PUMP) above the greatest value in SPON. Muscle VO2 was determined contraction-by-contraction using an ultrasonic flowmeter and venous oximeter, and normalised to tension-time integral (TTI). τVO2/TTI and τQ were less in S1SPON (mean ± s.d.: 13 ± 3 s and 12 ± 4 s, respectively) than in S2SPON (29 ± 19 s and 31 ± 13 s, respectively; P < 0.05). τVO2/TTI was unchanged by pump-perfusion (S1PUMP, 12 ± 4 s; S2PUMP, 24 ± 6 s; P < 0.001) despite increased O2 delivery; at S2 onset, venous O2 saturation was 21 ± 4% and 65 ± 5% in SPON and PUMP, respectively. VO2 kinetics remained slowed when contractions were initiated from a raised metabolic rate despite uniform muscle stimulation and increased O2 delivery. The intracellular mechanism may relate to a falling energy state, approaching saturating ADP concentration, and/or slowed mitochondrial activation; but further study is required. These data add to the evidence that muscle VO2 control is more complex than previously suggested. PMID:24469073

  12. Tackling the Saturation of Oxygen: The Use of Phosphorus and Sulphur as Proxies Within the Neutral ISM of Star-Forming Galaxies

    CERN Document Server

    James, Bethan L

    2015-01-01

    The abundance of oxygen in galaxies is widely used in furthering our understanding of galaxy formation and evolution. Unfortunately, direct measurements of O/H in the neutral gas are extremely difficult to obtain due to the fact that the only OI line available within the HST UV wavelength range (1150-3200A) is often saturated. As such, proxies for oxygen are needed to indirectly derive an O/H via the assumption that solar ratios based on local Milky Way sight lines hold in different environments. In this paper, we assess the validity of using two such proxies, PII and SII, within more typical star-forming environments. Using HST-COS FUV spectra of a sample of nearby star-forming galaxies, we find that P and S follow a trend, log(PII/SII)=1.73+/-0.18, which is in excellent agreement with the solar ratio of log(P/S)_sol=-1.71+/-0.04 over a large range of galaxy properties, i.e., metallicities in the range 0.03-3.2 Z_sol and HI column densities of log[N(HI)/cm^-2]=18.44-21.28. We additionally show evidence from ...

  13. Regional cerebral blood flow and oxygen consumption during normal human sleep

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Ken (Toho Univ., Tokyo (Japan). School of Medicine)

    1989-09-01

    Regional cerebral blood flow (rCBF), regional oxygen extraction fraction (rCEF) and regional cerebral metabolic rate for oxygen (rCMRO{sub 2}) were measured using the continuous inhalation technique for {sup 15}O with positron emission tomography (PET) during both wakefulness and sleep. Ten paid volunteers, with a mean age of 21.6 yrs., were deprived of sleep for a period of approximately 20 hours, and the experiments were performed mostly in the morning. {sup 15}O activity of both whole blood and the plasma, pixel count of PET, total arterial blood oxygen content were used for analysis of rCBF, rOEF and rCMRO{sub 2}. PET scannings were carried out mostly during the very light non-rapid eye movement (NREM) sleep, i.e. stage 1 and/or 2, and wakefulness. About 10 minutes after the start of continuous inhalation of {sup 15}O gas, the {sup 15}O activity of the brain was found to be in a steady-state condition. During this steady-state condition, PET scannings were performed for about 10 minutes. Regions of interest, square in shape and having an area of 2.8 cm{sup 3}, were set in each cortex on PET images of a horizontal cross-section of the brain, set at 45 mm above the orbitomeatal line. The rCBF and rCMRO{sub 2} were analysed in 5 of 10 male subjects during both wakefulness and NREM sleep, and only 3 were done during three sleep stages, including REM sleep. Levels of rCBF and rCMRO{sub 2} were found to be decreased in NREM sleep, and the decreasing rates were calculated at 10.2% and 7.6% from the level of wakefulness, respectively. There was no significant difference in the mean value of rOEF between wakefulness and NREM sleep. There were no significant regional differences found in the rate of decrease among the frontal, temporal and occipital cortices. It was considered that the decrease of rCBF and rCMRO{sub 2} during NREM sleep suggested a decrease of the activity levels in the cerebral functions. (author).

  14. Regional cerebral blood flow and oxygen consumption during normal human sleep

    International Nuclear Information System (INIS)

    Regional cerebral blood flow (rCBF), regional oxygen extraction fraction (rCEF) and regional cerebral metabolic rate for oxygen (rCMRO2) were measured using the continuous inhalation technique for 15O with positron emission tomography (PET) during both wakefulness and sleep. Ten paid volunteers, with a mean age of 21.6 yrs., were deprived of sleep for a period of approximately 20 hours, and the experiments were performed mostly in the morning. 15O activity of both whole blood and the plasma, pixel count of PET, total arterial blood oxygen content were used for analysis of rCBF, rOEF and rCMRO2. PET scannings were carried out mostly during the very light non-rapid eye movement (NREM) sleep, i.e. stage 1 and/or 2, and wakefulness. About 10 minutes after the start of continuous inhalation of 15O gas, the 15O activity of the brain was found to be in a steady-state condition. During this steady-state condition, PET scannings were performed for about 10 minutes. Regions of interest, square in shape and having an area of 2.8 cm3, were set in each cortex on PET images of a horizontal cross-section of the brain, set at 45 mm above the orbitomeatal line. The rCBF and rCMRO2 were analysed in 5 of 10 male subjects during both wakefulness and NREM sleep, and only 3 were done during three sleep stages, including REM sleep. Levels of rCBF and rCMRO2 were found to be decreased in NREM sleep, and the decreasing rates were calculated at 10.2% and 7.6% from the level of wakefulness, respectively. There was no significant difference in the mean value of rOEF between wakefulness and NREM sleep. There were no significant regional differences found in the rate of decrease among the frontal, temporal and occipital cortices. It was considered that the decrease of rCBF and rCMRO2 during NREM sleep suggested a decrease of the activity levels in the cerebral functions. (author)

  15. Effects of oxygen concentration and flow rate on cognitive ability and physiological responses in the elderly

    Institute of Scientific and Technical Information of China (English)

    Hyun-Jun Kim; Soon-Cheol Chung; Hyun-Kyung Park; Dae-Woon Lim; Mi-Hyun Choi; Hyun-Joo Kim; In-Hwa Lee; Hyung-Sik Kim; Jin-Seung Choi; Gye-Rae Tack

    2013-01-01

    The supply of highly concentrated oxygen positively affects cognitive processing in normal young adults. However, there have been few reports on changes in cognitive ability in elderly subjects following highly concentrated oxygen administration. This study investigated changes in cognitive ability, blood oxygen saturation (%), and heart rate (beats/min) in normal elderly subjects at three different levels of oxygen [21% (1 L/min), 93% (1 L/min), and 93% (5 L/min)] administered during a 1-back task. Eight elderly male (75.3 ± 4.3 years old) and 10 female (71.1 ± 3.9 years old) subjects, who were normal in cognitive ability as shown by a score of more than 24 points in the Mini-Mental State Examination-Korea, participated in the experiment. The experiment consisted of an adaptation phase after the start of oxygen administration (3 minutes), a control phase to obtain stable baseline measurements of heart rate and blood oxygen saturation before the task (2 minutes), and a task phase during which the 1-back task was performed (2 minutes). Three levels of oxygen were administered throughout the three phases (7 minutes). Blood oxygen saturation and heart rate were measured during each phase. Our results show that blood oxygen saturation increased, heart rate decreased, and response time in the 1-back task decreased as the concentration and amount of administered oxygen increased. This shows that administration of sufficient oxygen for optimal cognitive functioning increases blood oxygen saturation and decreases heart rate.

  16. Simultaneous blood-tissue exchange of oxygen, carbon dioxide, bicarbonate, and hydrogen ion.

    Science.gov (United States)

    Dash, Ranjan K; Bassingthwaighte, James B

    2006-07-01

    A detailed nonlinear four-region (red blood cell, plasma, interstitial fluid, and parenchymal cell) axially distributed convection-diffusion-permeation-reaction-binding computational model is developed to study the simultaneous transport and exchange of oxygen (O2) and carbon dioxide (CO2) in the blood-tissue exchange system of the heart. Since the pH variation in blood and tissue influences the transport and exchange of O2 and CO2 (Bohr and Haldane effects), and since most CO2 is transported as HCO3(-) (bicarbonate) via the CO2 hydration (buffering) reaction, the transport and exchange of HCO3(-) and H+ are also simulated along with that of O2 and CO2. Furthermore, the model accounts for the competitive nonlinear binding of O2 and CO2 with the hemoglobin inside the red blood cells (nonlinear O2-CO2 interactions, Bohr and Haldane effects), and myoglobin-facilitated transport of O2 inside the parenchymal cells. The consumption of O2 through cytochrome-c oxidase reaction inside the parenchymal cells is based on Michaelis-Menten kinetics. The corresponding production of CO2 is determined by respiratory quotient (RQ), depending on the relative consumption of carbohydrate, protein, and fat. The model gives a physiologically realistic description of O2 transport and metabolism in the microcirculation of the heart. Furthermore, because model solutions for tracer transients and steady states can be computed highly efficiently, this model may be the preferred vehicle for routine data analysis where repetitive solutions and parameter optimization are required, as is the case in PET imaging for estimating myocardial O2 consumption. PMID:16775761

  17. Successful hyperbaric oxygen therapy for refractory BK virus-associated hemorrhagic cystitis after cord blood transplantation.

    Science.gov (United States)

    Hosokawa, K; Yamazaki, H; Nakamura, T; Yoroidaka, T; Imi, T; Shima, Y; Ohata, K; Takamatsu, H; Kotani, T; Kondo, Y; Takami, A; Nakao, S

    2014-10-01

    BK virus-associated hemorrhagic cystitis (BKV-HC) is a common and major cause of morbidity in recipients of allogeneic hematopoietic stem cell transplantation. A 32-year-old woman developed severe BKV-HC on day 24 after cord blood transplantation (CBT). Despite supportive therapies - such as hyperhydration, forced diuresis, and urinary catheterization - macroscopic hematuria and bladder irritation persisted for over a month. Hyperbaric oxygen (HBO) therapy at 2.1 atmospheres for 90 min per day was started on day 64 after CBT. Macroscopic hematuria resolved within a week, and microscopic hematuria was no longer detectable within 2 weeks. Hematuria did not recur after 11 sessions of HBO therapy, and no significant side effects were observed during or after treatment. HBO therapy could thus be useful in controlling refractory BKV-HC after CBT. PMID:25040402

  18. Cerebral oxygen metabolism and cerebral blood flow in man during light sleep (stage 2)

    DEFF Research Database (Denmark)

    Madsen, P L; Schmidt, J F; Holm, S; Vorstrup, S; Lassen, N A; Wildschiødtz, Gordon

    We measured cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) during light sleep (stage 2) in 8 young healthy volunteers using the Kety-Schmidt technique with 133Xe as the inert gas. Measurements were performed during wakefulness and light sleep as verified by standard...... polysomnography. Unlike our previous study in man showing a highly significant 25% decrease in CMRO2 during deep sleep (stage 3-4) we found a modest but statistically significant decrease of 5% in CMRO2 during stage 2 sleep. Deep and light sleep are both characterized by an almost complete lack of mental activity....... They differ in respect of arousal threshold as a stronger stimulus is required to awaken a subject from deep sleep as compared to light sleep. Our results suggest that during non-rapid eye movement sleep cerebral metabolism and thereby cerebral synaptic activity is correlated to cerebral readiness...

  19. Continuous Perfusion of Saphenous Vein by Oxygenated Blood during Beating Coronary Surgery

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Mandegar

    2015-09-01

    Full Text Available Background: The saphenous vein remains the most commonly used conduit for coronary artery bypass surgery (CABG. However, the long-term success of surgical revascularization is largely limited by development of occlusion in vein grafts. Objectives: We sought to reduce graft ischemia by maintaining the blood flow into the harvested vein throughout surgery at lowest costs and without special devices. Patients and Methods: This study was conducted on three hundred patients aged 58.5 ± 8 years undergoing elective first-time off-pump CABG with saphenous veins. Results: In addition to preserving nutritional materials and oxygen, the veins harvested via this novel technique did not go into spasm and were not subjected to high-pressure distension, eventually resulting in minimal damage to the endothelium. Conclusions: This technique confers favorable myocardial function and protection in the presence of left ventricular dysfunction, especially in elderly patients.

  20. Effects of Changes in Colored Light on Brain and Calf Muscle Blood Concentration and Oxygenation

    Directory of Open Access Journals (Sweden)

    J. Weinzirl

    2011-01-01

    Full Text Available Color light therapy is a therapeutic method in complementary medicine. In color therapy, light of two contrasting colors is often applied in a sequential order. The aim of this study was to investigate possible physiological effects, i.e., changes in the blood volume and oxygenation in the brain and calf muscle of healthy subjects who were exposed to red and blue light in sequential order. The hypothesis was that if a subject is first exposed to blue and then red light, the effect of the red light will be enhanced due to the contrastingly different characteristics of the two colors. The same was expected for blue light, if first exposing a subject to red and then to blue light. Twelve healthy volunteers (six male, six female were measured twice on two different days by near-infrared spectroscopy during exposure to colored light. Two sequences of colored light were applied in a controlled, randomized, crossover design: first blue, then red, and vice versa. For the brain and muscle, the results showed no significant differences in blood volume and oxygenation between the two sequences, and a high interindividual physiological variability. Thus, the hypothesis had to be rejected. Comparing these data to results from a previous study, where subjects were exposed to blue and red light without sequential color changes, shows that the results of the current study appear to be similar to those of red light exposure. This may indicate that the exposure to red light was preponderant and thus effects of blue light were outweighed.

  1. Reduction in Cerebral Oxygenation After Prolonged Exercise in Hypoxia is Related to Changes in Blood Pressure.

    Science.gov (United States)

    Horiuchi, Masahiro; Dobashi, Shohei; Kiuchi, Masataka; Endo, Junko; Koyama, Katsuhiro; Subudhi, Andrew W

    2016-01-01

    We investigated the relation between blood pressure and cerebral oxygenation (COX) immediately after exercise in ten healthy males. Subjects completed an exercise and recovery protocol while breathing either 21% (normoxia) or 14.1% (hypoxia) O2 in a randomized order. Each exercise session included four sets of cycling (30 min/set, 15 min rest) at 50% of altitude-adjusted peak oxygen uptake, followed by 60 min of recovery. After exercise, mean arterial pressure (MAP; 87±1 vs. 84±1 mmHg, average values across the recovery period) and COX (68±1% vs. 58±1%) were lower in hypoxia compared to normoxia (Pblood pressure following exercise in hypoxia are (1) more pronounced than in normoxia, and (2) associated with reductions in COX. Together, these results suggest an impairment in cerebral autoregulation as COX followed changes in MAP more passively in hypoxia than in normoxia. These findings could help explain the increased risk for postexercise syncope at high altitude. PMID:26782200

  2. Influence of erythrocyte oxygenation and intravascular ATP on resting and exercising skeletal muscle blood flow in humans with mitochondrial myopathy

    DEFF Research Database (Denmark)

    Jeppesen, Tina D; Vissing, John; González-Alonso, José

    2012-01-01

    Oxygen (O(2)) extraction is impaired in exercising skeletal muscle of humans with mutations of mitochondrial DNA (mtDNA), but the muscle hemodynamic response to exercise has never been directly investigated. This study sought to examine the extent to which human skeletal muscle perfusion can...... healthy control subjects: 1) at rest during normoxia, hypoxia, hyperoxia and intra-femoral artery ATP infusion, and 2) during passive and dynamic one-legged knee-extensor exercises. At rest, blood flow (LBF), femoral arterial and venous blood oxygenation and plasma ATP were similar in the two groups...

  3. Role of hemoglobin from blood clam Scapharca kagoshimensis beyond oxygen transport.

    Science.gov (United States)

    Xu, Bin; Zhao, Jun; Jing, Zhao; Zhang, Yanan; Shi, Ying; Fan, Tingjun

    2015-05-01

    The evolutionary race between hosts and pathogens has led to a variety of adaptations. Little is known about the immunological role of hemoglobin (Hb) in antimicrobial immune responses. Results showed that a 31.2 kDa monodimer Hb (skHbI) and a 57.8 kDa heterotetramer Hb (skHbII) from the blood clam, Scapharca kagoshimensis, had phenoloxidase (PO)-like activities and antimicrobial activities. Both were found capable of oxidizing l-DOPA, catechol and hydroquinone. Their PO-like activities were visibly greatly inhibited by oxidase inhibitors, EDTA, and divalent metal ions, and greatly enhanced by isopropanol and Fe(2+), indicating that they have the properties of a metalloenzyme and a catecholase-type PO as well. They also showed obvious anti-bacterial activities against gram-positive bacteria but not against either gram-negative bacteria nor fungi. The anti-bacterial activities levels were a result of the generation of reactive oxygen species (ROS) of superoxide anions. These results indicate that skHbI and skHbII, not only function as iron-containing oxygen carriers, but also exert anti-bacterial activities and catecholase-type oxidizing activities. The fact that skHbII exerts high level of PO-like activity indicates different roles in the innate immunodefense system. These results may improve understanding of the multiple functions of invertebrate Hbs beyond serving as oxygen carriers and may provide insight into how the fundamental and universal mode of the innate immune system has persisted in respiratory proteins throughout the course of evolution. PMID:25700784

  4. Preparation, characterization and in vivo investigation of blood-compatible hemoglobin-loaded nanoparticles as oxygen carriers.

    Science.gov (United States)

    Lu, Mingzi; Zhao, Caiyan; Wang, Quan; You, Guoxing; Wang, Ying; Deng, Hongzhang; Chen, Gan; Xia, Sha; Zhao, Jingxiang; Wang, Bo; Li, Xianlei; Shao, Leihou; Wu, Yan; Zhao, Lian; Zhou, Hong

    2016-03-01

    Although many attempts have been made to design advanced hemoglobin-based oxygen carriers (HBOCs), no clinically viable product has been widely approved, because they do not perform normal blood functions, such as coagulation, hematologic reactions and stability. Additionally, the in vivo oxygenation of hemoglobin-loaded nanoparticles (HbPs) encapsulated with polymers has seldom been proved. Herein, HbPs of approximately 200nm with good stability were successfully fabricated and exhibited oxygen-carrying capacity. The HbPs preserve the biological and structure features of hemoglobin according to UV-vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy and circular dichroism (CD) spectral analysis. In vitro, the HbPs showed a viscosity comparable to that of blood with no obvious effects on red blood cell aggregation. At the same time, blood compatibility was characterized in terms of platelet function, clot strength, speed of clot formation, degree of fibrin cross-linking and hemolysis rate. After intravenous administration of HbPs to mice with controlled hemorrhages, blood flow recovery and maintenance of systemic oxygenation were observed. PMID:26708138

  5. Effect of intermittent hypoxia and exercise on blood rheology and oxygen transport in trained rats.

    Science.gov (United States)

    Núñez-Espinosa, Cristian; Douziech, Anne; Ríos-Kristjánsson, Juan Gabriel; Rizo, David; Torrella, Joan Ramon; Pagès, Teresa; Viscor, Ginés

    2014-02-01

    Intermittent hypobaric hypoxia (IHH) exposure, accompanied or not with active recovery, can help to skeletal muscle repair. However, the erythropoietic response elicited can disturb blood rheology and thus alter the oxygen delivery to tissues. Male Sprague-Dawley rats were studied in two basal states: untrained and trained and compared with early (1-3 days) and late (7-14 days) stages of damage recovery in three groups of trained rats that had suffered skeletal muscle injury: Control, passive recovery rats; HYP, rats exposed to IHH after muscle damage; and EHYP, trained rats that performed light aerobic exercise sessions in addition to IHH. Hematocrit, RBC count and hemoglobin were only elevated in the late stage of recovery in HYP (13%; 14% and 8%) and EHYP (18%; 13% and 15%) groups. Blood viscosity increased about double for EHYP rats. It is concluded that intermittent exposure to hypobaric hypoxia in combination with light aerobic exercise in normoxia has an erythropoietic effect, but also provides advantageous hemorheological conditions for the perfusion of damaged muscle. PMID:24373840

  6. A review of blood substitutes: examining the history, clinical trial results, and ethics of hemoglobin-based oxygen carriers

    OpenAIRE

    Jiin-Yu Chen; Michelle Scerbo; George Kramer

    2009-01-01

    The complications associated with acquiring and storing whole blood for transfusions have launched substantial efforts to develop a blood substitute. The history of these efforts involves a complicated mixture of science, ethics, and business. This review focuses on clinical trials of the three hemoglobin-based oxygen carriers (HBOC) that have progressed to Phase II or III clinical trials: He-mAssist (Baxter; Deerfield, IL, US), PolyHeme (Northfield; Evanston, IL, US), and Hemopure (Biopure; ...

  7. MR vascular fingerprinting: A new approach to compute cerebral blood volume, mean vessel radius, and oxygenation maps in the human brain.

    Science.gov (United States)

    Christen, T; Pannetier, N A; Ni, W W; Qiu, D; Moseley, M E; Schuff, N; Zaharchuk, G

    2014-04-01

    In the present study, we describe a fingerprinting approach to analyze the time evolution of the MR signal and retrieve quantitative information about the microvascular network. We used a Gradient Echo Sampling of the Free Induction Decay and Spin Echo (GESFIDE) sequence and defined a fingerprint as the ratio of signals acquired pre- and post-injection of an iron-based contrast agent. We then simulated the same experiment with an advanced numerical tool that takes a virtual voxel containing blood vessels as input, then computes microscopic magnetic fields and water diffusion effects, and eventually derives the expected MR signal evolution. The parameter inputs of the simulations (cerebral blood volume [CBV], mean vessel radius [R], and blood oxygen saturation [SO2]) were varied to obtain a dictionary of all possible signal evolutions. The best fit between the observed fingerprint and the dictionary was then determined by using least square minimization. This approach was evaluated in 5 normal subjects and the results were compared to those obtained by using more conventional MR methods, steady-state contrast imaging for CBV and R and a global measure of oxygenation obtained from the superior sagittal sinus for SO2. The fingerprinting method enabled the creation of high-resolution parametric maps of the microvascular network showing expected contrast and fine details. Numerical values in gray matter (CBV=3.1±0.7%, R=12.6±2.4μm, SO2=59.5±4.7%) are consistent with literature reports and correlated with conventional MR approaches. SO2 values in white matter (53.0±4.0%) were slightly lower than expected. Numerous improvements can easily be made and the method should be useful to study brain pathologies. PMID:24321559

  8. Serum Lactate Is not Correlated with Mixed or Central Venous Oxygen Saturation for Detecting Tissue Hypo Perfusion During Coronary Artery Bypass Graft Surgery: A Prospective Observational Study

    Directory of Open Access Journals (Sweden)

    Shahrbano Shahbazi

    2013-12-01

    Full Text Available Objectives:: Effective assessment of tissue perfusion is highly important during Coronary Artery Bypass Graft (CABG. Mixed venous O2 saturation (Svo2 is one of the best and routinely used markers of tissue perfusion. However, this method is costly and leads to considerable complications. Thus, the present study aimed to determine whether the Svo2 can be substituted with central venous saturation (Scvo2 and if there is any correlation between lactate level and Svo2. Methods:: This prospective observational study was conducted on 62 patients scheduled for CABG. After induction and maintenance of anesthesia, blood samples drawn from central venous, pulmonary artery, and radial artery were used to measure Scvo2, Svo2 and serum lactate level respectively before and after Cardio Pulmonary Bypass (CPB. Pearson’s correlation test was used to determine the correlation between Svo2 and Scvo2 as well as between Svo2 and serum lactate level. Besides, P < 0.05 was considered as statistically significant. Results:: Overall, 62 Patients, 33 males (53.2% and 29 females (46.8% were enrolled into the present study. The most common coexisting illness was hypertension detected in 33 patients (53.2% followed by hypercholesterolemia in 28 ones (44.4%. In this study, Svo2 was positively correlated with Scvo2 (r = 0.63, P < 0.001. However, no correlation was found between Svo2 and lactate (r = 0.124, P = 0.348. Conclusions:: In summary, Scvo2 is considered as the best substitute of Svo2 for detecting tissue hypo perfusion during CPB. Although the lactate level had been considered as an appropriate marker of tissue perfusion and ischemia, it was not correlated to Svo2 during CABG.

  9. Mechanical indentation improves cerebral blood oxygenation signal quality of functional near-infrared spectroscopy (fNIRS) during breath holding

    Science.gov (United States)

    Vogt, William C.; Romero, Edwin; LaConte, Stephen M.; Rylander, Christopher G.

    2013-03-01

    Functional near-infrared spectroscopy (fNIRS) is a well-known technique for non-invasively measuring cerebral blood oxygenation, and many studies have demonstrated that fNIRS signals can be related to cognitive function. However, the fNIRS signal is attenuated by the skin, while scalp blood content has been reported to influence cerebral oxygenation measurements. Mechanical indentation has been shown to increase light transmission through soft tissues by causing interstitial water and blood flow away from the compressed region. To study the effects of indentation on fNIRS, a commercial fNIRS system with 16 emitter/detector pairs was used to measure cerebral blood oxygenation at 2 Hz. This device used diffuse reflectance at 730 nm and 850 nm to calculate deoxy- and oxy-hemoglobin concentrations. A borosilicate glass hemisphere was epoxied over each sensor to function as both an indenter and a lens. After placing the indenter/sensor assembly on the forehead, a pair of plastic bands was placed on top of the fNIRS headband and strapped to the head to provide uniform pressure and tightened to approx. 15 N per strap. Cerebral blood oxygenation was recorded during a breath holding regime (15 second hold, 15 second rest, 6 cycles) in 4 human subjects both with and without the indenter array. Results showed that indentation increased raw signal intensity by 85 +/- 35%, and that indentation increased amplitude of hemoglobin changes during breath cycles by 313% +/- 105%. These results suggest that indentation improves sensing of cerebral blood oxygenation, and may potentially enable sensing of deeper brain tissues.

  10. A new method to measure local oxygen consumption in human skeletal muscle during dynamic exercise using near-infrared spectroscopy

    OpenAIRE

    Binzoni, Tiziano; Cooper, Chris E; Wittekind, Anna L.; Beneke, Ralph; Elwell, Clare E; Van De Ville, Dimitri; Leung, Terence S.

    2010-01-01

    Near infrared spectroscopy (NIRS) can readily report on changes in blood volume and oxygenation. However, it has proved more problematic to measure real-time changes in blood flow and oxygen consumption. Here we report the development of a novel method using NIRS to measure local oxygen consumption in human muscle. The method utilizes the blood volume changes induced by the muscle pump during rhythmically contracting exercising skeletal muscle. We found that the saturation of the blood during...

  11. Short term non-invasive ventilation post-surgery improves arterial blood-gases in obese subjects compared to supplemental oxygen delivery - a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Zoremba Norbert

    2011-05-01

    Full Text Available Abstract Background In the immediate postoperative period, obese patients are more likely to exhibit hypoxaemia due to atelectasis and impaired respiratory mechanics, changes which can be attenuated by non-invasive ventilation (NIV. The aim of the study was to evaluate the duration of any effects of early initiation of short term pressure support NIV vs. traditional oxygen delivery via venturi mask in obese patients during their stay in the PACU. Methods After ethics committee approval and informed consent, we prospectively studied 60 obese patients (BMI 30-45 undergoing minor peripheral surgery. Half were randomly assigned to receive short term NIV during their PACU stay, while the others received routine treatment (supplemental oxygen via venturi mask. Premedication, general anaesthesia and respiratory settings were standardized. We measured arterial oxygen saturation by pulse oximetry and blood gas analysis on air breathing. Inspiratory and expiratory lung function was measured preoperatively (baseline and at 10 min, 1 h, 2 h, 6 h and 24 h after extubation, with the patient supine, in a 30 degrees head-up position. The two groups were compared using repeated-measure analysis of variance (ANOVA and t-test analysis. Statistical significance was considered to be P Results There were no differences at the first assessment. During the PACU stay, pulmonary function in the NIV group was significantly better than in the controls (p Conclusion Early initiation of short term NIV during in the PACU promotes more rapid recovery of postoperative lung function and oxygenation in the obese. The effect lasted 24 hours after discontinuation of NIV. Patient selection is necessary in order to establish clinically relevant improvements. Trial Registration# DRKS00000751; http://www.germanctr.de

  12. [Early Detection of Iliac Artery Rupture by Sudden Steep Reduction of Regional Saturation of Oxygen at the Ipsilateral Foot during Transcatheter Aortic Valve Implantation--A Case Report].

    Science.gov (United States)

    Saito, Shun; Ishii, Hisanari

    2016-02-01

    An 80-year-old woman with severe aortic stenosis was planned to undergo transcatheter aortic valve implantation (TAVI) under general anesthesia. Due to severe stenosis of the femoral arteries, the left iliac artery was cut down and a 16 F Edwards SAPIEN Expandable Sheath (eSheath : Edwards Lifesciences, Irvine, CA) was inserted into the artery smoothly. After balloon aortic valvuloplasty (BAV), an artificial valve was tried to deploy but stuck in the middle of eSheath. Suddenly regional saturation of oxygen (rSO2) at the ipsilateral foot decreased steeply without other significant hemodynamic instabilities. At insertion site of eSheath, the left external iliac artery rupture occurred. To our surprise, there was almost no major bleeding because of the artery spasm and suppression of the large bore sheath. eSheath and the stuck valve were taken out together and TAVI was discontinued. The artery was replaced with a graft, and rSO2 of the foot recovered. Her aortic stenosis improved to moderate by balloon aortic valvuloplasty (BAV) according to transthoracic echocardiography. The patient was discharged on foot without complications. To our knowledge, this is a first report of a silent rupture of the iliac artery during TAVI to be detected by sudden decrease of the foot rSO2 and treated with no fatal events. PMID:27017778

  13. Effects of exposure to rice-crop residue burning smoke on pulmonary functions and oxygen saturation level of human beings in Patiala (India).

    Science.gov (United States)

    Agarwal, Ravinder; Awasthi, Amit; Singh, Nirankar; Gupta, Prabhat Kumar; Mittal, Susheel K

    2012-07-01

    Pulmonary Function Tests (PFTs) like Force Vital Capacity (FVC), Force Expiratory Volume in one second (FEV₁), Peak Expiratory Flow (PEF) and Force Expiratory Flow between 25 and 75% of FVC (FEF(25-75%)) and Oxygen Saturation (SpO₂) level of 50 healthy inhabitants with respect to rice crop residue burning were investigated for three rice cultivation periods from 2007 to 2009. The subjects were residents of five sampling sites selected in Patiala city. Concentration of Suspended Particulate Matter (SPM), Sulfur dioxide (SO₂), Nitrogen dioxide (NO₂) and Particulate Matter (PM) of size less than 10 and 2.5 μm (PM₁₀ and PM₂.₅) were measured by using High Volume Sampler (HVS) and Cascade Anderson Impactor. Results show that rice crop residue burning increases the pollution level in the ambient air, and PFTs undergo a significant decrease in their respective values. No significant change was seen in SpO₂ level during rice crop residue burning. In 2008, an increase of 10 μg m⁻³ in PM₂.₅, PM₁₀, SPM and NO₂ was associated significantly with decrease in FVC in percentages predicted -1.541, -1.002, -1.178, -0.232%, respectively. The decrease in air quality due to open rice crop residue burning has sub acute effect on pulmonary functions of healthy subjects and that SO₂ and NO₂ have less adverse effects on pulmonary functions than with different size Particulate Matter. PMID:22578846

  14. Imaging changes in blood volume and oxygenation in the newborn infant brain using three-dimensional optical tomography

    International Nuclear Information System (INIS)

    Induced haemodynamic and blood oxygenation changes occurring within the brain of a ventilated newborn infant have been imaged in three dimensions using optical tomography. Noninvasive measurements of the flight times of transmitted light were acquired during illumination of the brain by laser pulses at wavelengths of 780 nm and 815 nm. The oxygen and carbon dioxide partial pressures were adjusted through alterations to the ventilator settings, resulting in changes to the cerebral blood volume and oxygenation. Three-dimensional images were generated using the physiologically associated differences in the measured data, obviating the need for data calibration using a separate reference measurement. The results exhibit large changes in absorption coefficient at both wavelengths. Images corresponding to differences in concentrations of oxy- and deoxyhaemoglobin are in qualitative agreement with known physiological data

  15. A novel nano-sized bionic function interface for enhancing the ability of red blood cells to carry oxygen

    International Nuclear Information System (INIS)

    A nano-sized bionic function interface was prepared by immobilizing red blood cells onto a silver electrode, which was modified with cysteamine and colloidal gold. Scanning electron microscopy and electrochemical impedance spectroscopy were used to characterize its surface. Cyclic voltammograms in phosphate buffer solution of pH 7.0 exhibited a pair of redox peaks for oxygen at -378 and -207 mV, respectively. The reduction peak currents at -378 mV were linearly proportional to the oxygen concentration in the range from 12.6 μM to 1.39 mM. Cyclic voltammetry also indicated that the functional surface enhanced the ability of red blood cells to transport oxygen. (author)

  16. Quantitative spatially resolved measurement of tissue chromophore concentrations using photoacoustic spectroscopy: application to the measurement of blood oxygenation and haemoglobin concentration

    International Nuclear Information System (INIS)

    A new approach based on pulsed photoacoustic spectroscopy for non-invasively quantifying tissue chromophore concentrations with high spatial resolution has been developed. The technique is applicable to the quantification of tissue chromophores such as oxyhaemoglobin (HbO2) and deoxyhaemoglobin (HHb) for the measurement of physiological parameters such as blood oxygen saturation (SO2) and total haemoglobin concentration. It can also be used to quantify the local accumulation of targeted contrast agents used in photoacoustic molecular imaging. The technique employs a model-based inversion scheme to recover the chromophore concentrations from photoacoustic measurements. This comprises a numerical forward model of the detected time-dependent photoacoustic signal that incorporates a multiwavelength diffusion-based finite element light propagation model to describe the light transport and a time-domain acoustic model to describe the generation, propagation and detection of the photoacoustic wave. The forward model is then inverted by iteratively fitting it to measurements of photoacoustic signals acquired at different wavelengths to recover the chromophore concentrations. To validate this approach, photoacoustic signals were generated in a tissue phantom using nanosecond laser pulses between 740 nm and 1040 nm. The tissue phantom comprised a suspension of intralipid, blood and a near-infrared dye in which three tubes were immersed. Blood at physiological haemoglobin concentrations and oxygen saturation levels ranging from 2% to 100% was circulated through the tubes. The signal amplitude from different temporal sections of the detected photoacoustic waveforms was plotted as a function of wavelength and the forward model fitted to these data to recover the concentrations of HbO2 and HHb, total haemoglobin concentration and SO2. The performance was found to compare favourably to that of a laboratory CO-oximeter with measurement resolutions of ±3.8 g l-1 (±58 μM) and ±4

  17. Quantitative spatially resolved measurement of tissue chromophore concentrations using photoacoustic spectroscopy: application to the measurement of blood oxygenation and haemoglobin concentration

    Energy Technology Data Exchange (ETDEWEB)

    Laufer, Jan; Delpy, Dave; Elwell, Clare; Beard, Paul [Department of Medical Physics and Bioengineering, University College London, Malet Place Engineering Building, London WC1E 6BT (United Kingdom)

    2007-01-07

    A new approach based on pulsed photoacoustic spectroscopy for non-invasively quantifying tissue chromophore concentrations with high spatial resolution has been developed. The technique is applicable to the quantification of tissue chromophores such as oxyhaemoglobin (HbO{sub 2}) and deoxyhaemoglobin (HHb) for the measurement of physiological parameters such as blood oxygen saturation (SO{sub 2}) and total haemoglobin concentration. It can also be used to quantify the local accumulation of targeted contrast agents used in photoacoustic molecular imaging. The technique employs a model-based inversion scheme to recover the chromophore concentrations from photoacoustic measurements. This comprises a numerical forward model of the detected time-dependent photoacoustic signal that incorporates a multiwavelength diffusion-based finite element light propagation model to describe the light transport and a time-domain acoustic model to describe the generation, propagation and detection of the photoacoustic wave. The forward model is then inverted by iteratively fitting it to measurements of photoacoustic signals acquired at different wavelengths to recover the chromophore concentrations. To validate this approach, photoacoustic signals were generated in a tissue phantom using nanosecond laser pulses between 740 nm and 1040 nm. The tissue phantom comprised a suspension of intralipid, blood and a near-infrared dye in which three tubes were immersed. Blood at physiological haemoglobin concentrations and oxygen saturation levels ranging from 2% to 100% was circulated through the tubes. The signal amplitude from different temporal sections of the detected photoacoustic waveforms was plotted as a function of wavelength and the forward model fitted to these data to recover the concentrations of HbO{sub 2} and HHb, total haemoglobin concentration and SO{sub 2}. The performance was found to compare favourably to that of a laboratory CO-oximeter with measurement resolutions of {+-}3

  18. Deciphering phonemes from syllables in blood oxygenation level-dependent signals in human superior temporal gyrus.

    Science.gov (United States)

    Zhang, Qingtian; Hu, Xiaolin; Luo, Huan; Li, Jianmin; Zhang, Xiaolu; Zhang, Bo

    2016-03-01

    Linguistic units such as phonemes and syllables are important for speech perception. How the brain encodes these units is not well understood. Many neuroimaging studies have found distinct representations of consonant-vowel syllables that shared one phoneme and differed in the other phoneme (e.g. /ba/ and /da/), but it is unclear whether this discrimination ability is due to the neural coding of phonemes or syllables. We combined functional magnetic resonance imaging with multivariate pattern analysis to explore this question. Subjects listened to nine Mandarin syllables in a consonant-vowel form. We successfully decoded phonemes from the syllables based on the blood oxygenation level-dependent signals in the superior temporal gyrus (STG). Specifically, a classifier trained on the cortical patterns elicited by a set of syllables, which contained two phonemes, could distinguish the cortical patterns elicited by other syllables that contained the two phonemes. The results indicated that phonemes have unique representations in the STG. In addition, there was a categorical effect, i.e. the cortical patterns of consonants were similar, and so were the cortical patterns of vowels. Further analysis showed that phonemes exhibited stronger encoding specificity in the mid-STG than in the anterior STG. PMID:26751256

  19. Cotransport of hydroxyapatite nanoparticles and hematite colloids in saturated porous media: Mechanistic insights from mathematical modeling and phosphate oxygen isotope fractionation

    Science.gov (United States)

    Wang, Dengjun; Jin, Yan; Jaisi, Deb P.

    2015-11-01

    The fate and transport of individual type of engineered nanoparticles (ENPs) in porous media have been studied intensively and the corresponding mechanisms controlling ENPs transport and deposition are well-documented. However, investigations regarding the mobility of ENPs in the concurrent presence of another mobile colloidal phase such as naturally occurring colloids (colloid-mediated transport of ENPs) are largely lacking. Here, we investigated the cotransport and retention of engineered hydroxyapatite nanoparticles (HANPs) with naturally occurring hematite colloids in water-saturated sand columns under environmentally relevant transport conditions, i.e., pH, ionic strength (IS), and flow rate. Particularly, phosphate oxygen isotope fractionation of HANPs during cotransport was explored at various ISs and flow rates to examine the mechanisms controlling the isotope fractionation of HANPs in abiotic transport processes (physical transport). During cotransport, greater mobility of both HANPs and hematite occurred at higher pHs and flow rates, but at lower ISs. Intriguingly, the mobility of both HANPs and hematite was substantially lower during cotransport than the individual transport of either, attributed primarily to greater homo- and hetero-aggregation when both particles are copresent in the suspension. The shapes of breakthrough curves (BTCs) and retention profiles (RPs) during cotransport for both particles evolved from blocking to ripening with time and from flat to hyperexponential with depth, respectively, in response to decreases in pH and flow rate, and increases in IS. The blocking BTCs and RPs that are flat or hyperexponential can be well-approximated by a one-site kinetic attachment model. Conversely, a ripening model that incorporates attractive particle-particle interaction has to be employed to capture the ripening BTCs that are impacted by particle aggregation during cotransport. A small phosphate oxygen isotope fractionation (≤ 1.8

  20. Modelling of the Effect of End-Tidal Carbon Dioxide on Cerebral Oxygen Saturation in Beach Chair Position under General Anaesthesia.

    Science.gov (United States)

    Kim, So Yeon; Chae, Dong Woo; Chun, Yong-Min; Jeong, Kyu Hee; Park, Kyungsoo; Han, Dong Woo

    2016-07-01

    Patients undergoing shoulder surgery in the beach chair position (BCP) under general anaesthesia may be at risk of cerebral desaturation. Increasing end-tidal carbon dioxide (EtCO2 ) is the most convenient and powerful method for the management of cerebral desaturation. The purpose of this study was to investigate the quantitative relationship between EtCO2 and cerebral oxygen saturation (rSO2 ) and to identify the associated influencing factors. Fifty-one patients undergoing arthroscopic shoulder surgery in the BCP under general anaesthesia completed this study. Desflurane and remifentanil were used, and EtCO2 was steadily increased and then decreased by adjusting the ventilator settings every 3 min. so that time lag of rSO2 response to EtCO2 changes could be delineated. Near-infrared spectroscopy was used to monitor rSO2 response. An indirect response model was used to examine the relationship between EtCO2 and rSO2 . To determine the relevant covariates, a stepwise approach was used. There was a linear relationship between rSO2 and EtCO2 with a slight delay in the peak of rSO2 relative to EtCO2 . Increase in end-tidal desflurane concentration led to a slower response of rSO2 to the changes of EtCO2 (p = 0.0002). The presence of diabetes mellitus reduced the reactivity of rSO2 to EtCO2 changes (p < 0.0001). This model-based approach revealed that diabetes mellitus attenuates the response of rSO2 to changes in EtCO2 . The management of cerebral desaturation by hypercapnia in patients with diabetes may be less effective than in non-diabetic patients under general anaesthesia with BCP. PMID:26707006

  1. A venous outflow method for measurement of rapid changes of the cerebral blood flow and oxygen consumption in the rat.

    Science.gov (United States)

    Nilsson, B; Siesjö, B K

    1983-01-01

    A technique for continuous measurement of cerebral venous outflow in the rat is described. The method involves cannulation of one retroglenoid vein close to its exit from the skull, and diversion of cerebral venous blood through a closed extracorporal circuit with a drop recording device, the blood being returned to the central venous circulation via a catheter in the external jugular vein. Occlusion of the contralateral retroglenoid vein increases measured flow and minimizes extracerebral contamination of the diverted cerebral venous blood. The venous outflow system is not further isolated from cerebral or potential extracerebral collaterals. Thus, the mass of tissue drained cannot be exactly defined anatomically. However, the experiments involving changes of PP, arterial CO2 tension, and induction of epileptic seizure activity, and simultaneous indirect measurements with radioactive tracer technique, indicate that significant extracerebral contamination does not occur and that in short term measurements the venous outflow represents cerebral blood flow (CBF) in a constant mass of (dorsal and central, mainly forebrain) cerebral tissue. Measurement of arterial blood pressure and pressure in the cisterna magna allows calculation of cerebral perfusion pressure (PP). By simultaneous measurement of arterial and cerebral venous oxygen content changes in cerebral oxygen consumption (CMRO2) can be calculated. The method has been applied to document several situations of transient CBF and CMRO2 changes. PMID:6658967

  2. Arterial Oxygen Content Is Precisely Maintained by Graded Erythrocytotic Responses in Settings of High/Normal Serum Iron Levels, and Predicts Exercise Capacity: An Observational Study of Hypoxaemic Patients with Pulmonary Arteriovenous Malformations

    OpenAIRE

    Santhirapala, Vatshalan; Williams, Louisa C.; Tighe, Hannah C.; James E Jackson; Shovlin, Claire L.

    2014-01-01

    Background Oxygen, haemoglobin and cardiac output are integrated components of oxygen transport: each gram of haemoglobin transports 1.34 mls of oxygen in the blood. Low arterial partial pressure of oxygen (PaO2), and haemoglobin saturation (SaO2), are the indices used in clinical assessments, and usually result from low inspired oxygen concentrations, or alveolar/airways disease. Our objective was to examine low blood oxygen/haemoglobin relationships in chronically compensated states without...

  3. Arterial Oxygen Content Is Precisely Maintained by Graded Erythrocytotic Responses in Settings of High/Normal Serum Iron Levels, and Predicts Exercise Capacity: An Observational Study of Hypoxaemic Patients with Pulmonary Arteriovenous Malformations

    OpenAIRE

    Vatshalan Santhirapala; Williams, Louisa C.; Tighe, Hannah C.; Jackson, James E.; Shovlin, Claire L

    2014-01-01

    BACKGROUND: Oxygen, haemoglobin and cardiac output are integrated components of oxygen transport: each gram of haemoglobin transports 1.34 mls of oxygen in the blood. Low arterial partial pressure of oxygen (PaO2), and haemoglobin saturation (SaO2), are the indices used in clinical assessments, and usually result from low inspired oxygen concentrations, or alveolar/airways disease. Our objective was to examine low blood oxygen/haemoglobin relationships in chronically compensated states withou...

  4. Functional neuroanatomy in depressed patients with sexual dysfunction: blood oxygenation level dependent functional MR imaging

    International Nuclear Information System (INIS)

    To demonstrate the functional neuroanatomy associated with sexual arousal visually evoked in depressed males who have underlying sexual dysfunction using Blood Oxygenation Level Dependent-based fMRI. Ten healthy volunteers (age range 21-55: mean 32.5 years), and 10 depressed subjects (age range 23-51: mean 34.4 years, mean Beck Depression Inventory score of 39.6 ± 5.9, mean Hamilton Rating Scale Depression (HAMD)-17 score of 33.5 ± 6.0) with sexual arousal dysfunction viewed erotic and neutral video films during functional magnetic resonance imaging (fMRI) with 1.5 T MR scanner (GE Signa Horizon). The fMRI data were obtained from 7 oblique planes using gradient-echo EPI (flip angle/TR/TE=90 .deg. /6000 ms/50 ms). The visual stimulation paradigm began with 60 sec of black screen, 150 sec of neutral stimulation with a documentary video film, 30 sec of black screen, 150 sec of sexual stimulation with an erotic video film followed by 30 sec of black screen. The brain activation maps and their quantification were analyzed by SPM99 program. There was a significant difference of brain activation between two groups during visual sexual stimulation. In depressed subjects, the level of activation during the visually evoked sexual arousal was significantly less than that of healthy volunteers, especially in the cerebrocortical areas of the hypothalamus, thalamus, caudate nucleus, and inferior and superior temporal gyri. On the other hand, the cerebral activation patterns during the neutral condition in both groups showed no significant differences (ρ < 0.01). This study is the first demonstration of the functional neuroanatomy of the brain associated with sexual dysfunction in depressed patients using fMRI. In order to validate our physiological neuroscience results, further studies that would include patients with other disorders and sexual dysfunction, and depressed patients without sexual dysfunction and their treatment response are needed

  5. Functional neuroanatomy in depressed patients with sexual dysfunction: blood oxygenation level dependent functional MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jong Chul [Chonnam National Univ. Hospital, Kwangju (Korea, Republic of)

    2004-06-15

    To demonstrate the functional neuroanatomy associated with sexual arousal visually evoked in depressed males who have underlying sexual dysfunction using Blood Oxygenation Level Dependent-based fMRI. Ten healthy volunteers (age range 21-55: mean 32.5 years), and 10 depressed subjects (age range 23-51: mean 34.4 years, mean Beck Depression Inventory score of 39.6 {+-} 5.9, mean Hamilton Rating Scale Depression (HAMD)-17 score of 33.5 {+-} 6.0) with sexual arousal dysfunction viewed erotic and neutral video films during functional magnetic resonance imaging (fMRI) with 1.5 T MR scanner (GE Signa Horizon). The fMRI data were obtained from 7 oblique planes using gradient-echo EPI (flip angle/TR/TE=90 .deg. /6000 ms/50 ms). The visual stimulation paradigm began with 60 sec of black screen, 150 sec of neutral stimulation with a documentary video film, 30 sec of black screen, 150 sec of sexual stimulation with an erotic video film followed by 30 sec of black screen. The brain activation maps and their quantification were analyzed by SPM99 program. There was a significant difference of brain activation between two groups during visual sexual stimulation. In depressed subjects, the level of activation during the visually evoked sexual arousal was significantly less than that of healthy volunteers, especially in the cerebrocortical areas of the hypothalamus, thalamus, caudate nucleus, and inferior and superior temporal gyri. On the other hand, the cerebral activation patterns during the neutral condition in both groups showed no significant differences ({rho} < 0.01). This study is the first demonstration of the functional neuroanatomy of the brain associated with sexual dysfunction in depressed patients using fMRI. In order to validate our physiological neuroscience results, further studies that would include patients with other disorders and sexual dysfunction, and depressed patients without sexual dysfunction and their treatment response are needed.

  6. Do blood components affect the production of reactive oxygen species (ROS by equine synovial cells in vitro?

    Directory of Open Access Journals (Sweden)

    Patrícia M. Brossi

    2012-12-01

    Full Text Available Blood-derived products are commonly administered to horses and humans to treat many musculoskeletal diseases, due to their potential antioxidant and anti-inflammatory effects. Nevertheless, antioxidant effects have never been shown upon horse synovial fluid cells in vitro. If proved, this could give a new perspective to justify the clinical application of blood-derived products. The aim of the present study was to investigate the antioxidant effects of two blood-derived products - plasma (unconditioned blood product - UBP and a commercial blood preparation (conditioned blood product - CBP¹ - upon stimulated equine synovial fluid cells. Healthy tarsocrural joints (60 were tapped to obtain synovial fluid cells; these cells were pooled, processed, stimulated with lipopolysaccharide (LPS or phorbol 12-myristate 13-acetate (PMA, and evaluated by flow cytometry for the production of reactive oxygen species (ROS. Upon addition of any blood-derived product here used - UBP and CBP - there was a significant decrease in the oxidative burst of synovial fluid cells (P<0.05. There was no difference between UBP and CBP effects. In conclusion, treatment of stimulated equine synovial cells with either UBP or CBP efficiently restored their redox equilibrium.

  7. Effects of Cortical Spreading Depression on Synaptic Activity, Blood Flow and Oxygen Consumption in Rat Cerebral Cortex

    DEFF Research Database (Denmark)

    Hansen, Henning Piilgaard

    2010-01-01

    As the title of this thesis indicates I have during my PhD studied the effects of cortical spreading depression (CSD) on synaptic activity, blood flow and oxygen consumption in rat cerebral cortex. This was performed in vivo using an open cranial window approach in anesthetized rats. I applied...... two different sets of interneurons. Our data imply that for a given cortical area the amplitude of vascular signals will depend critically on the type of input and hence on the type of neurons activated. In the second study I investigated the effect of cortical spreading depression (CSD) on the evoked...... Laser-Doppler Flowmetry for measurements of cerebral blood flow, glass microelectrodes for recording of synaptic activity – local field potentials – and ongoing cortical electrical activity and a Clark type electrode for measurements of tissue partial pressure of oxygen (tpO2). Offline calculations of...

  8. In vivo measurements of regional hemoglobin oxygen saturation values and limb-to-arm ratios of near-infrared spectroscopy for tissue oxygenation monitoring of lower extremities in healthy subjects

    Directory of Open Access Journals (Sweden)

    Boezeman RP

    2014-12-01

    Full Text Available Reinout PE Boezeman,1 Johannes C Kelder,2 Frans GJ Waanders,3 Frans L Moll,4 Jean-Paul PM de Vries1 1Department of Vascular Surgery, St Antonius Hospital, Nieuwegein, the Netherlands; 2Department of Research and Developments, St Antonius Hospital, Nieuwegein, the Netherlands; 3Department of Perfusion, St Antonius Hospital, Nieuwegein, the Netherlands; 4Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, the Netherlands Objective: Near-infrared spectroscopy (NIRS is a noninvasive technique that allows monitoring of regional hemoglobin oxygen saturation (rSO2 values and might have a role in the diagnosis of peripheral arterial disease. We assessed the reproducibility and inter-subject variability of rSO2 values and rSO2 limb-to-arm ratios (LARs in lower extremities of healthy subjects. Methods: The rSO2 values and rSO2 LARs were calculated in eight healthy subjects without peripheral arterial disease. The rSO2 values were measured at rest at six fixed spots at each lower limb and a reference spot at each upper arm. NIRS provided the rSO2 values without involvement of any other processing technique. After measurements were completed, rSO2 LARs were calculated by dividing the rSO2 value of a lower extremity spot by the rSO2 value of the arm. Measurements were performed twice on 1 day and repeated on 4 different days. Results: Mean coefficients of variation of measurements of rSO2 values and rSO2 LARs at the same spot in the same subject were respectively less than 6% and 8% for every measurement spot over time. Coefficients of variation of measurements at the same spot between different subjects were less than 15% and 19% for every measurement spot respectively. Conclusion: NIRS is an easily applicable, noninvasive tool for measurement of tissue oxygenation of lower extremities in healthy subjects. The reproducibility of rSO2 values and rSO2 LARs at the same measurement spot in the same subject is good. Keywords: NIRS, rSO2

  9. Pulse oximetry optical sensor using oxygen-bound haemoglobin.

    Science.gov (United States)

    Cohen, Z J V; Haxha, S; Aggoun, A

    2016-05-01

    In this paper we report a unique approach to measuring oxygen saturation levels by utilising the wavelength of the haemoglobin instead of the conventional absorption difference. Two experiments are set up to measure the wavelength of the haemoglobin bound to oxygen at different oxygen saturation levels with the help of a spectrometer. We report a unique low cost and robust wavelength monitoring SpO2 sensor that measures the SpO2 by using the colour of the blood and not the absorption difference of oxyhaemoglobin and deoxyhaemoglobin. With use of a spectrometer, we show that the wavelength of the oxygen-bound haemoglobin has a relation to the oxygen saturation level. The proposed device is designed and experimentally implemented with a colour sensor to measure the SpO2 level of the blood. PMID:27137621

  10. Improvement of Brain Tissue Oxygenation by Inhalation of Carbogen

    DEFF Research Database (Denmark)

    Ashkanian, M.; Borghammer, P.; Gjedde, A.; Ostergaard, L.; Vafaee, M.

    2008-01-01

    confirmed by statistical cluster analysis. Oxygen and carbogen were equally potent in increasing oxygen saturation of arterial blood (Sa(O2)). The present data demonstrate that inhalation of carbogen increases both CBF and Sa(O2) in healthy adults. In conclusion we speculate that carbogen inhalation is...... sufficient for optimal oxygenation of healthy brain tissue, whereas carbogen induces concomitant increases of CBF and Sa(O2).......Hyperoxic therapy for cerebral ischemia is suspected to reduce cerebral blood flow (CBF), due to the vasoconstrictive effect of oxygen on cerebral arterioles. We hypothesized that vasodilation predominates when 5% CO(2) is added to the inhaled oxygen (carbogen). Therefore, we used positron emission...

  11. The association between forced expiratory volume in one second (FEV1) and pulse oximetric measurements of arterial oxygen saturation (SpO2) in the patients with COPD: A preliminary study

    OpenAIRE

    2014-01-01

    Background: The study was aimed to explore the association between arterial oxygen saturation (SpO2) and spirometer parameters of disease severity in chronic obstructive pulmonary disease (COPD) patients with a view to identify whether the pulse oximetry can be used as an alternative to arterial values in the clinical management of COPD patients in a routine practice. Materials and Methods: Thirty-one patients with COPD were included in this study. After evaluation of each patient through his...

  12. Measuring venous oxygenation using the photoplethysmograph waveform

    OpenAIRE

    Walton, Z. D.; Kyriacou, P. A.; Silverman, D. G.; Shelley, K. H.

    2010-01-01

    OBJECTIVE: We investigate the hypothesis that the photoplethysmograph (PPG) waveform can be analyzed to infer regional venous oxygen saturation. METHODS: Fundamental to the successful isolation of the venous saturation is the identification of PPG characteristics that are unique to the peripheral venous system. Two such characteristics have been identified. First, the peripheral venous waveform tends to reflect atrial contraction. Second, ventilation tends to move venous blood preferenti...

  13. Dehydration affects cerebral blood flow but not its metabolic rate for oxygen during maximal exercise in trained humans

    DEFF Research Database (Denmark)

    Trangmar, Steven J; Chiesa, Scott T; Stock, Christopher G;

    2014-01-01

    Intense exercise is associated with a reduction in cerebral blood flow (CBF), but regulation of CBF during strenuous exercise in the heat with dehydration is unclear. We assessed internal (ICA) and common carotid artery (CCA) haemodynamics (indicative of CBF and extra-cranial blood flow), middle...... cerebral artery velocity (MCA Vmean), arterial-venous differences and blood temperature in 10 trained males during incremental cycling to exhaustion in the heat (35°C) in control, dehydrated and rehydrated states. Dehydration reduced body mass (75.8 ± 3 vs. 78.2 ± 3 kg), increased internal temperature (38...... decline in cerebral perfusion with dehydration was accompanied by increased O2 extraction (P < 0.05), resulting in a maintained cerebral metabolic rate for oxygen (CMRO2). In all conditions, reductions in ICA and MCA Vmean were associated with declining cerebral vascular conductance, increasing jugular...

  14. Mapping of cerebral metabolic rate of oxygen using dynamic susceptibility contrast and blood oxygen level dependent MR imaging in acute ischemic stroke

    International Nuclear Information System (INIS)

    MR-derived cerebral metabolic rate of oxygen utilization (CMRO2) has been suggested to be analogous to PET-derived CMRO2 and therefore may be used for detection of viable tissue at risk for infarction. The purpose of this study was to evaluate MR-derived CMRO2 mapping in acute ischemic stroke in relation to established diffusion- and perfusion-weighted imaging. In 23 patients (mean age 63 ± 18.7 years, 11 women) with imaging findings for acute ischemic stroke, relative oxygen extraction fraction was calculated from quantitative transverse relaxation times (T2, T2*) and relative cerebral blood volume using a quantitative blood oxygenation level dependent (BOLD) approach in order to detect a local increase of deoxyhemoglobin. Relative CMRO2 (rCMRO2) maps were calculated by multiplying relative oxygen extraction fraction (rOEF) by cerebral blood flow, derived from PWI. After co-registration, rCMRO2 maps were evaluated in comparison with apparent diffusion coefficient (ADC) and time-to-peak (TTP) maps. Mean rCMRO2 values in areas with diffusion-restriction or TTP/ADC mismatch were compared with rCMRO2 values in the contralateral tissue. In tissue with diffusion restriction, mean rCMRO2 values were significantly decreased compared to perfusion-impaired (17.9 [95 % confidence interval 10.3, 25.0] vs. 58.1 [95 % confidence interval 50.1, 70.3]; P < 0.001) and tissue in the contralateral hemisphere (68.2 [95 % confidence interval 61.4, 75.0]; P < 0.001). rCMRO2 in perfusion-impaired tissue showed no significant change compared to tissue in the contralateral hemisphere (58.1 [95 % confidence interval 50.1, 70.3] vs. 66.7 [95 % confidence interval 53.4, 73.4]; P = 0.34). MR-derived CMRO2 was decreased within diffusion-restricted tissue and stable within perfusion-impaired tissue, suggesting that this technique may be adequate to reveal different pathophysiological stages in acute stroke. (orig.)

  15. Mapping of cerebral metabolic rate of oxygen using dynamic susceptibility contrast and blood oxygen level dependent MR imaging in acute ischemic stroke

    Energy Technology Data Exchange (ETDEWEB)

    Gersing, Alexandra S.; Schwaiger, Benedikt J. [Technical University Munich, Klinikum rechts der Isar, Department of Neuroradiology, Munich (Germany); University of California, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Ankenbrank, Monika; Toth, Vivien; Bauer, Jan S.; Zimmer, Claus [Technical University Munich, Klinikum rechts der Isar, Department of Neuroradiology, Munich (Germany); Janssen, Insa [Technical University Munich, Department of Neurosurgery, Munich (Germany); Kooijman, Hendrik [Philips Healthcare, Hamburg (Germany); Wunderlich, Silke [Technical University Munich, Department of Neurology, Munich (Germany); Preibisch, Christine [Technical University Munich, Klinikum rechts der Isar, Department of Neuroradiology, Munich (Germany); Technical University Munich, Department of Neurology, Munich (Germany)

    2015-12-15

    MR-derived cerebral metabolic rate of oxygen utilization (CMRO{sub 2}) has been suggested to be analogous to PET-derived CMRO{sub 2} and therefore may be used for detection of viable tissue at risk for infarction. The purpose of this study was to evaluate MR-derived CMRO{sub 2} mapping in acute ischemic stroke in relation to established diffusion- and perfusion-weighted imaging. In 23 patients (mean age 63 ± 18.7 years, 11 women) with imaging findings for acute ischemic stroke, relative oxygen extraction fraction was calculated from quantitative transverse relaxation times (T2, T2*) and relative cerebral blood volume using a quantitative blood oxygenation level dependent (BOLD) approach in order to detect a local increase of deoxyhemoglobin. Relative CMRO{sub 2} (rCMRO{sub 2}) maps were calculated by multiplying relative oxygen extraction fraction (rOEF) by cerebral blood flow, derived from PWI. After co-registration, rCMRO{sub 2} maps were evaluated in comparison with apparent diffusion coefficient (ADC) and time-to-peak (TTP) maps. Mean rCMRO{sub 2} values in areas with diffusion-restriction or TTP/ADC mismatch were compared with rCMRO{sub 2} values in the contralateral tissue. In tissue with diffusion restriction, mean rCMRO{sub 2} values were significantly decreased compared to perfusion-impaired (17.9 [95 % confidence interval 10.3, 25.0] vs. 58.1 [95 % confidence interval 50.1, 70.3]; P < 0.001) and tissue in the contralateral hemisphere (68.2 [95 % confidence interval 61.4, 75.0]; P < 0.001). rCMRO{sub 2} in perfusion-impaired tissue showed no significant change compared to tissue in the contralateral hemisphere (58.1 [95 % confidence interval 50.1, 70.3] vs. 66.7 [95 % confidence interval 53.4, 73.4]; P = 0.34). MR-derived CMRO{sub 2} was decreased within diffusion-restricted tissue and stable within perfusion-impaired tissue, suggesting that this technique may be adequate to reveal different pathophysiological stages in acute stroke. (orig.)

  16. Application of language blood oxygenation level dependent functional MRI in the navigating operation of neurosurgery

    International Nuclear Information System (INIS)

    Objective: To verify the accuracy of blood oxygenation level dependent (BOLD)-based activation using electrocortical stimulation mapping (ESM) and explore the value of language fMRI in the navigating operation of neurosurgery. Methods: In 8 cases with brain tumors, BOLD-fMRI examinations were done before the operations. Under the state of awake anesthesia,the patients were aroused and ESM was conducted. Point-to-point comparison between the BOLD signal activations and the ESM was carried out under the surveillance of the neuro-navigation technology. In order to observe the sensibility and specificity of BOLD activations, the location of BOLD activations and the point of ESM was compared to calculate the stimulating positive points inside the regions of BOLD signals (real positive), outside BOLD regions (pseudo- negative), the stimulating negative points inside the regions of BOLD signals (pseudo-positive), and outside BOLD region (real negative). Two kinds of criteria for assessment were used. One was that the positive stimulating points were located in BOLD regions, and the other was that the positive stimulating points were located within 1 cm around the range of BOLD regions. Removal of the lesions were conducted with the tissue 1 cm around the language region preserved, and the cortex inside 0.5-1.0 cm distance from the positive points were retained. Results: Of the 8 cases, only 6 finished the tasks. Among them, 3 cases were with astrocytoma of grade 2, 2 were with astrocytoma of grade 3, and one with glioblastoma. The total number of stimulating points was 48, among which the positive points were 11. When the first criteria was applied, the sensitivity was 72.7% (8/11), and the specificity was 81.8% (30/37). When the second criteria was applied, the sensitivity was 82.0% (9/11), and the specificity was 75.6% (28/37). Follow-up after operation showed no aphasia occurred. Conclusions: BOLD-fMRI had a high sensitivity and specificity in displaying the language

  17. Local cerebral blood flow (1CBF) and oxygen consumption (1CMRO2) in evolving irreversible ischemic infarction: a study with positron tomography and oxygen-15

    International Nuclear Information System (INIS)

    In 25 patients suffering from cerebral ischemia set up in the area of the internal carotid artery the local cerebral blood flow (lCBF) and local cerebral oxygen consumption (lCMRO2) were measured by the method of continuous inhalation of oxygen 15-labelled gas combined with positron emission tomography. These two local parameters and their ratio, the local oxygen extraction rate (lO2E), were studied inside the brain region tending spontaneously towards ischemic necrosis, a zone defined by means of repeated tomodensitometric examinations. The essential facts observed are the variability of the lCBF and the lO2E values, from extremely low to extremely high, whereas the collapse of the lCMRO2 is constant. Consequently this last parameter alone would be a good prognostic index, an lCMRO2 decrease to a level below about 70% of the controlateral value indicating that the necrosis is spontaneously irreparable. These results are discussed in the light of published data

  18. Elevated global cerebral blood flow, oxygen extraction fraction and unchanged metabolic rate of oxygen in young adults with end-stage renal disease: an MRI study

    International Nuclear Information System (INIS)

    To noninvasively assess global cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) in young adults with end-stage renal disease (ESRD). Thirty-six patients and 38 healthy volunteers were included and took part in MR examinations, blood and neuropsychological tests. CBF and OEF were measured by phase-contrast and T2-relaxation-under-spin-tagging MRI techniques, respectively. CMRO2 was computed from CBF, OEF and hematocrit according to Fick's principle. Correlations were performed between MR measurements, blood biochemistry measurements and neuropsychological test scores. Compared with controls, ESRD patients had elevated CBF (72.9 ± 12.5 vs. 63.8 ± 8.5 ml min-1 100 g-1, P < 0.001), elevated OEF (47.2 ± 10.2 vs. 35.8 ± 5.4 %, P < 0.001), but unaffected CMRO2 (199.5 ± 36.4 vs. 193.8 ± 28.6 μmol O2 min-1 100 g-1, P = 0.879). Hematocrit negatively correlated with CBF (r = -0.640, P < 0.001) and OEF (r = -0.701, P < 0.001), but not with CMRO2. Altered neuropsychological test scores of ESRD patients were associated with OEF and CBF, but not with CMRO2. There were weak relationships between eGFR and hematocrit (r = 0.308, P = 0.068) or CBF (r = 0.318, P = 0.059). Our findings suggested that anaemic young adults with ESRD may afford higher CBF and OEF to maintain a normal CMRO2. Despite this compensatory process, however, cognitive function was still impaired and its severity was correlated with their CBF and OEF abnormality. (orig.)

  19. Elevated global cerebral blood flow, oxygen extraction fraction and unchanged metabolic rate of oxygen in young adults with end-stage renal disease: an MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Gang; Lou, Yaxian; Pan, Zhiying; Liu, Ya [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Nanjing University of Aeronautics and Astronautics, College of Aivil Aviation, Nanjing, Jiangsu (China); Wen, Jiqiu; Li, Xue; Zhang, Zhe [Medical School of Nanjing University, National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing, Jiangsu (China); Lu, Hanzhang [University of Texas Southwestern Medical Center, Advanced Imaging Research Center, Dallas, TX (United States); Liu, Wei [Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, Guangdong (China); Liu, Hui [Siemens MR NEA Collaboration, Siemens Ltd., Shanghai (China); Chen, Huijuan; Kong, Xiang; Luo, Song; Jiang, Xiaolu; Zhang, Zongjun; Zhang, Long Jiang; Lu, Guang Ming [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China)

    2016-06-15

    To noninvasively assess global cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO{sub 2}) in young adults with end-stage renal disease (ESRD). Thirty-six patients and 38 healthy volunteers were included and took part in MR examinations, blood and neuropsychological tests. CBF and OEF were measured by phase-contrast and T2-relaxation-under-spin-tagging MRI techniques, respectively. CMRO{sub 2} was computed from CBF, OEF and hematocrit according to Fick's principle. Correlations were performed between MR measurements, blood biochemistry measurements and neuropsychological test scores. Compared with controls, ESRD patients had elevated CBF (72.9 ± 12.5 vs. 63.8 ± 8.5 ml min{sup -1} 100 g{sup -1}, P < 0.001), elevated OEF (47.2 ± 10.2 vs. 35.8 ± 5.4 %, P < 0.001), but unaffected CMRO{sub 2} (199.5 ± 36.4 vs. 193.8 ± 28.6 μmol O{sub 2} min{sup -1} 100 g{sup -1}, P = 0.879). Hematocrit negatively correlated with CBF (r = -0.640, P < 0.001) and OEF (r = -0.701, P < 0.001), but not with CMRO{sub 2}. Altered neuropsychological test scores of ESRD patients were associated with OEF and CBF, but not with CMRO{sub 2}. There were weak relationships between eGFR and hematocrit (r = 0.308, P = 0.068) or CBF (r = 0.318, P = 0.059). Our findings suggested that anaemic young adults with ESRD may afford higher CBF and OEF to maintain a normal CMRO{sub 2}. Despite this compensatory process, however, cognitive function was still impaired and its severity was correlated with their CBF and OEF abnormality. (orig.)

  20. Alterations in oxygen transport following WR-2721

    International Nuclear Information System (INIS)

    During the Phase I clinical trials of WR-2721 and alkylating agent chemotherapy, venous blood samples were obtained prior to and immediately following the WR-2721 infusion. The authors have observed a marked increase in the oxygen saturation of venous blood following WR-2721. The highest values generally occurred within the first 2 hours after the completion of the WR-2721 infusion. No significant differences were found between the pre and post WR-2721 values for either the venous pH, CO2, or bicarbonate levels. Despite increased P/sub v/O2, the patient's heart rates, blood pressures, or respiratory rates did not change pre and post WR-2721. In 12 patients oxygen-hemoglobin dissociation curves and intracellular red cell pH's were obtained before and after WR-2721. Despite the significant increase in oxygenation of venous blood after WR-2721, there were no changes in either oxygen-hemoglobin dissociation or intracellular red cell pH to account for this increase. The oxygen consumption of peripheral blood granulocytes was measured prior to and following 15 courses of WR-2721. A marked decrease in granulocyte oxygen consumption was observed in 6/8 patients who had a significant increase in P/sub v/O2. Our preliminary investigations suggest that the increased venous blood oxygen content may be secondary to a reduction in normal tissue oxygen consumption. WR-2721 may afford protection by both decreasing oxygen consumption and delivery to normal tissues and increasing intracellular sulfhydryls

  1. 脑氧饱和度监测在反屈氏位腹腔镜手术中的应用%Variation characteristics of cerebral tissue oxygen saturation in the reverse trendelenburg position during laparoscopic surgery

    Institute of Scientific and Technical Information of China (English)

    刘清海; 王天龙

    2014-01-01

    Objective To observe the variation characteristics of cerebral tissue oxygen saturation in the reverse (30°) Trendelenburg position during laparoscopic surgery.Methods Patients with gastric cancer undergoing laparoscopic surgery were monitored intraoperatively using the FORE-SIGHT cerebral oximeter.Two sensors were placed on the subject's forehead bilaterally for continuous monitoring of cerebral tissue oxygen saturation (SCTO2).The subjects were in the reverse Trendelenburg position during surgery.SCTO2,end-tidal carbon dioxide(PETCO2),mean arterial pressure (MAP) and Temperature were recorded every fifteen minutes after carbon dioxide pneumoperitoneum.Meanwhile,concentration of hemoglobin are examinated at preoperation and postoperation.All patients were followed up for neurological complications.Results 20 patients were monitored.The patients' age ranged from 34 to 80 years.The base value of SCTO2 was (72±6)% on the left sensor,and (72± 4)% on the right sensor.The SCTO2 maximum values were(84±5)% on the left sensor,and(81±4)% on the right sensor after 75 min carbon dioxide pneumoperitoneum.During pneumoperitoneum the SCTO2 values increased by (8±6)% on the left sensor,and (8±6)% on the right sensor.The maximum increasing amplitudes of SCTO2 were 15.49%(left) and 17.14%(right) respectively during CO2 pneumoperitoneum.The PETCO2 values before pneumoperitoneum,15 min and 75 min pneumoperitoneum were(33.8±2.3) mmHg,(38.4±2.8) mmHg and(40.8±2.2) mmHg,respectively.There were no significant difference in MAP,Temperature and hemoglobin concentration.Neurological complications of postoperation were not found.Conclusions The SCTO2 values increased under reverse trendelenburg and carbon dioxide pneumoperitoneum because of the raised FiO2 and cerebral blood flow due to hypercapnia which can contributed to maintain cerebral oxygen supply and demand balance.%目的 观察反屈氏位腹腔镜手术期间,患者

  2. Synergy between shear-induced migration and secondary flows on red blood cells transport in arteries: considerations on oxygen transport.

    Science.gov (United States)

    Biasetti, Jacopo; Spazzini, Pier Giorgio; Hedin, Ulf; Gasser, T Christian

    2014-08-01

    Shear-induced migration of red blood cells (RBCs) is a well-known phenomenon characterizing blood flow in the small vessels (micrometre to millimetre size) of the cardiovascular system. In large vessels, like the abdominal aorta and the carotid artery (millimetre to centimetre size), the extent of this migration and its interaction with secondary flows has not been fully elucidated. RBC migration exerts its influence primarily on platelet concentration, oxygen transport and oxygen availability at the luminal surface, which could influence vessel wall disease processes in and adjacent to the intima. Phillips' shear-induced particle migration model, coupled to the Quemada viscosity model, was employed to simulate the macroscopic behaviour of RBCs in four patient-specific geometries: a normal abdominal aorta, an abdominal aortic aneurysm (AAA), a normal carotid bifurcation and a stenotic carotid bifurcation. Simulations show a migration of RBCs from the near-wall region with a lowering of wall haematocrit (volume fraction of RBCs) on the posterior side of the normal aorta and on the lateral-external side of the iliac arteries. A marked migration is observed on the outer wall of the carotid sinus, along the common carotid artery and in the carotid stenosis. No significant migration is observed in the AAA. The spatial and temporal patterns of wall haematocrit are correlated with the near-wall shear layer and with the secondary flows induced by the vessel curvature. In particular, secondary flows accentuate the initial lowering in RBC near-wall concentration by convecting RBCs from the inner curvature side to the outer curvature side. The results reinforce data in literature showing a decrease in oxygen partial pressure on the inner curvature wall of the carotid sinus induced by the presence of secondary flows. The lowering of wall haematocrit is postulated to induce a decrease in oxygen availability at the luminal surface through a diminished concentration of

  3. Pulmonary blood flow and pressure as well as arterial blood oxygenation simulations in ventilated artificial patient supported by continuous rotary blood pump.

    OpenAIRE

    ZielińSki, Krzysztof; Golczewski, Tomasz; Fresiello, Libera; Di Molfetta, Arianna; Ferrari, Gianfranco; Kozarski, Maciej; Darowski, Marek

    2011-01-01

    Objectives: Our previous study suggested insignificant impairment of pulmonary circulation during artificial ventilation if the inspiration time is smaller than the duration of 2-3 heart cycles. This was due to pulmonary blood volume periodic changes. The aim of this study is to analyze the influence of left ventricular assistance by continuous rotary blood pump (RBP) on hemodynamic in ventilated, virtual patient. Methods: Virtual RBP was added to a previously elaborated hybrid (pneumonumeric...

  4. Regional changes in cerebral blood flow oxygenation can indicate global changes in cerebral blood flow during coronary artery occlusion in juvenile pigs

    International Nuclear Information System (INIS)

    Near infrared spectroscopy (NIRS) is a widely employed method for assessment of regional cerebral oxygenation (RcStO2). RcStO2 values are expected to vary with changes in the relative amount of oxyhaemoglobin. The present experimental study aimed to assess the response of RcStO2 to controlled alterations of carotid blood flow (CQ). Landrace pigs were anesthetized followed by surgical preparation. Cyclic variations in cardiac output were accomplished by intermittently occluding the main stem of the left coronary artery. A flow measurement probe for assessing CQ was placed around the left carotid artery. One NIRS probe was placed on the left ipsilateral forehead to assess regional cerebral oximetry. Simultaneous registration of CQ and RcStO2 was conducted. There was a strong correlation for variation in CQ and RcStO2 signal values. Based on coherence analysis the fraction of power of the RcStO2 that was coherent with the CQ signal reached 0.84 ± 0.12 (P < 0.05) for frequencies lower than 0.1 Hz. The agreement of the sample-to-sample co-variation, as assessed by the Pearson correlation coefficient, was 0.83 ± 0.08 (P < 0.05). One explanatory component for variations in cerebral oxygenation verified by NIRS should be attributed to variations in the cerebral blood flow. (paper)

  5. Coupling of cerebral blood flow and oxygen metabolism is conserved for chromatic and luminance stimuli in human visual cortex.

    Science.gov (United States)

    Leontiev, Oleg; Buracas, Giedrius T; Liang, Christine; Ances, Beau M; Perthen, Joanna E; Shmuel, Amir; Buxton, Richard B

    2013-03-01

    The ratio of the changes in cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO(2)) during brain activation is a critical determinant of the magnitude of the blood oxygenation level dependent (BOLD) response measured with functional magnetic resonance imaging (fMRI). Cytochrome oxidase (CO), a key component of oxidative metabolism in the mitochondria, is non-uniformly distributed in visual area V1 in distinct blob and interblob regions, suggesting significant spatial variation in the capacity for oxygen metabolism. The goal of this study was to test whether CBF/CMRO(2) coupling differed when these subpopulations of neurons were preferentially stimulated, using chromatic and luminance stimuli to preferentially stimulate either the blob or interblob regions. A dual-echo spiral arterial spin labeling (ASL) technique was used to measure CBF and BOLD responses simultaneously in 7 healthy human subjects. When the stimulus contrast levels were adjusted to evoke similar CBF responses (mean 65.4% ± 19.0% and 64.6% ± 19.9%, respectively for chromatic and luminance contrast), the BOLD responses were remarkably similar (1.57% ± 0.39% and 1.59% ± 0.35%) for both types of stimuli. We conclude that CBF-CMRO(2) coupling is conserved for the chromatic and luminance stimuli used, suggesting a consistent coupling for blob and inter-blob neuronal populations despite the difference in CO concentration. PMID:23238435

  6. Effect of some saturated and unsaturated fatty acids on prostaglandin biosynthesis in washed human blood platelets from (1-/sup 14/ C)arachidonic acid

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, K.C.; Awasthi, K.K.; Lindegard, P.; Tiwari, K.P.

    1982-03-01

    The effects of some saturated (lauric, palmitic and stearic) an unsaturated (linoleic, gamma-linolenic, alpha-linolenic and oleic) fatty acids at 0.1. 0.25 and 0.5 mM concentrations on the in vitro metabolization of (1-14 C) arachidonic acid by washed human blood platelets have been studied. Effects of these fatty acids were studied with intact as well as lysed platelet preparations. With intact platelet preparations it was found that (i) all unsaturated fatty acids enhanced the biosynthesis of TxB2, PGE2, PGD2 and PGF2 alpha, (ii) unsaturated fatty acids reduced the formation of HHT and HETE with the exception of oleic acid which showed very little effect, (iii) unsaturated fatty acids reduced the formation of MDA, whereas palmitic and stearic acids increased its formation and (iv) all unsaturated fatty acids reduced the synthesis of prostaglandin endoperoxides. These results support our previous observations where effects of fatty acids were examined at higher concentrations (10). At 0.1 mM FA concentration, inconsistent results were obtained. With lysed platelet preparations all cyclooxygenase products were reduced in presence of unsaturated fatty acids, whereas HETE formation was reduced only in presence of linoleic and gamma-linolenic acids. Electron micrographs of washed platelet suspensions were obtained with untreated platelet preparations and platelet preparations treated with 0.25 and 0.5 mM linoleic acid concentrations. The results are discussed in the light of a possible soap-like effect of FA salt on platelets.

  7. A review of blood substitutes: examining the history, clinical trial results, and ethics of hemoglobin-based oxygen carriers

    Directory of Open Access Journals (Sweden)

    Jiin-Yu Chen

    2009-01-01

    Full Text Available The complications associated with acquiring and storing whole blood for transfusions have launched substantial efforts to develop a blood substitute. The history of these efforts involves a complicated mixture of science, ethics, and business. This review focuses on clinical trials of the three hemoglobin-based oxygen carriers (HBOC that have progressed to Phase II or III clinical trials: HemAssist (Baxter; Deerfield, IL, US, PolyHeme (Northfield; Evanston, IL, US, and Hemopure (Biopure; Cambridge, MA, US. Published animal studies and clinical trials carried out in a perioperative setting have demonstrated that these products successfully transport and deliver oxygen, but all may induce hypertension and lead to unexpectedly low cardiac outputs. Overall, these studies suggest that HBOCs resulted in only modest blood saving during and after surgery, no improvement in mortality and an increased incidence of adverse reactions. To date, the results from these perioperative studies have not led to regulatory approval. All three companies instead chose to focus their efforts on large trials of trauma patients in the pre-hospital setting. Baxter abandoned the development of HemAssist after a trial in the U.S. was prematurely halted when the first 100 patients showed significantly increased mortality rates as compared to patients treated with blood products. Northfield's PolyHeme trial demonstrated a non-significant trend towards increased mortality and a very modest reduction in the subsequent need for blood. The testing of Biopure's Hemopure for trauma patients has been halted for several years because of FDA concerns over trial design and study justification. Ethical concerns have also been raised regarding the design and implementation of all HBOC clinical trials. Thus, the available evidence suggests that HemAssist, Polyheme, and Hemopure are associated with a significant level of cardiovascular dysfunction. The next generation of HBOCs remains

  8. Vascular Steal Explains Early Paradoxical Blood Oxygen Level-Dependent Cerebrovascular Response in Brain Regions with Delayed Arterial Transit Times

    Directory of Open Access Journals (Sweden)

    Julien Poublanc

    2013-04-01

    Full Text Available Introduction: Blood oxygen level-dependent (BOLD magnetic resonance imaging (MRI during manipulation of inhaled carbon dioxide (CO2 can be used to measure cerebrovascular reactivity (CVR and map regions of exhausted cerebrovascular reserve. These regions exhibit a reduced or negative BOLD response to inhaled CO2. In this study, we sought to clarify the mechanism behind the negative BOLD response by investigating its time delay (TD. Dynamic susceptibility contrast (DSC MRI with the injection of a contrast agent was used as the gold standard in order to provide measurement of the blood arrival time to which CVR TD could be compared. We hypothesize that if negative BOLD responses are the result of a steal phenomenon, they should be synchronized with positive BOLD responses from healthy brain tissue, even though the blood arrival time would be delayed. Methods: On a 3-tesla MRI system, BOLD CVR and DSC images were collected in a group of 19 patients with steno-occlusive cerebrovascular disease. For each patient, we generated a CVR magnitude map by regressing the BOLD signal with the end-tidal partial pressure of CO2 (PETCO2, and a CVR TD map by extracting the time of maximum cross-correlation between the BOLD signal and PETCO2. In addition, a blood arrival time map was generated by fitting the DSC signal with a gamma variate function. ROI masks corresponding to varying degrees of reactivity were constructed. Within these masks, the mean CVR magnitude, CVR TD and DSC blood arrival time were extracted and averaged over the 19 patients. CVR magnitude and CVR TD were then plotted against DSC blood arrival time. Results: The results show that CVR magnitude is highly correlated to DSC blood arrival time. As expected, the most compromised tissues with the longest blood arrival time have the lowest (most negative CVR magnitude. However, CVR TD shows a noncontinuous relationship with DSC blood arrival time. CVR TD is well correlated to DSC blood arrival time

  9. Effects of growth, diving history, and high altitude on blood oxygen capacity in harbor seals

    Science.gov (United States)

    Kodama, A. M.; Elsner, R.; Pace, N.

    1977-01-01

    Blood volume and body composition for diving and nondiving harbor seals were measured at six-week intervals during a 10-month period of captitivity. Whole body hematocrit, red cell volume per kg of lean body mass, and total circulating hemoglobin per kg lean body mass were significantly higher in the diving group, but relatively large blood volumes expressed in terms of body weight (11-12%) were found in both groups. A pair of harbor seals exposed to high altitude for about three months registered significant increases in red cell volume, blood hemoglobin levels, and blood volume expressed in terms of body weight; results of alveolar gas analyses indicate that hyperventilation also occurred. These typical mammalian responses to hypoxia suggest that the harbor seal's large blood volume and high hemoglobin content are an expression of phylogenetic control, and that in spite of its adaptability to apnea during its diving life, the animal cannot be considered preacclimatized to high altitude.

  10. Effect of Hyperbaric Oxygen Therapy on whole blood cyanide concentrations in carbon monoxide intoxicated patients from fire accidents

    Directory of Open Access Journals (Sweden)

    Hilsted Linda

    2010-06-01

    Full Text Available Abstract Background Hydrogen cyanide (HCN and carbon monoxide (CO may be important components of smoke from fire accidents. Accordingly, patients admitted to hospital from fire accidents may have been exposed to both HCN and CO. Cyanide (CN intoxication results in cytotoxic hypoxia leading to organ dysfunction and possibly death. While several reports support the use of hyperbaric oxygen therapy (HBO for the treatment of severe CO poisoning, limited data exist on the effect of HBO during CN poisoning. HBO increases the elimination rate of CO haemoglobin in proportion to the increased oxygen partial pressure and animal experiments have shown that in rats exposed to CN intoxication, HBO can increase the concentration of CN in whole blood. Objective The purpose of the present study was to determine whole blood CN concentrations in fire victims before and after HBO treatment. Materials and methods The patients included were those admitted to the hospital because of CO intoxication, either as fire victims with smoke inhalation injuries or from other exposures to CO. In thirty-seven of these patients we measured CN concentrations in blood samples, using a Conway/microdiffusion technique, before and after HBO. The blood samples consisted of the remaining 2 mL from the arterial blood gas analysis. CN concentration in blood from fire victims was compared to 12 patients from non-fire accidents but otherwise also exposed to CO intoxication. Results The mean WB-CN concentration before patients received HBO did not differ significantly between the two groups of patients (p = 0.42. The difference between WB-CN before and after HBO did not differ significantly between the two groups of patients (p = 0.7. Lactate in plasma before and after did not differ significantly between the two groups of patients. Twelve of the 25 fire patients and one of the non-fire patients had been given a dose of hydroxycobalamin before HBO. Discussion and Conclusion CN

  11. Influence of passive stretch on muscle blood flow, oxygenation and central cardiovascular responses in healthy young males.

    Science.gov (United States)

    Kruse, Nicholas T; Silette, Christopher R; Scheuermann, Barry W

    2016-05-01

    The aim of this study was to examine the effect of skeletal muscle stretching on peripheral, central, and autonomic cardiovascular responses in humans. Twelve healthy males completed a controlled passive stretch of the plantar flexors for 4 min at three different intensities. Doppler ultrasound velocimetry and imaging techniques assessed mean leg blood flow (MLBF), antegrade blood flow, and retrograde blood flow of the popliteal artery. Near-infrared spectroscopy assessed the concentration of deoxygenated hemoglobin + myoglobin ([HHb]) and the sum of its deoxygenated and oxygenated forms [i.e., blood volume ([Hbtot])]. Heart rate (HR) and mean arterial pressure were measured simultaneously to peripheral hemodynamic responses. During stretch there was an increase (P < 0.05) in antegrade and retrograde blood flow along with [HHb] and [Hbtot] relative to baseline, whereas MLBF was not altered. HR increased (P < 0.01) in a stretch intensity- and time-dependent manner, suggesting a threshold tension must be met that results in a mechanoreflex-mediated increase in HR. After stretch there was an increase (P < 0.05) in [Hbtot] and MLBF in each condition, suggesting that stretch creates a poststretch hyperemic response. Furthermore, retrograde blood flow was decreased (P < 0.05) after stretch in each stretch condition. Mean arterial pressure was decreased (P < 0.05) after moderate-intensity stretching. Collectively, our data provide novel mechanistic evidence on cardiovascular responses to skeletal muscle stretching in humans. Moreover, the reductions in MAP and retrograde blood flow suggest that stretch transiently reduces myogenic vascular tone in a poststretch resting period. PMID:26945077

  12. Quantification of tumour vasculature and hypoxia by immunohistochemical staining and HbO2 saturation measurements

    OpenAIRE

    Fenton, B. M.; Paoni, S F; Lee, J.; Koch, C.J. (Christian); Lord, E M

    1999-01-01

    Despite the possibility that tumour hypoxia may limit radiotherapeutic response, the underlying mechanisms remain poorly understood. A new methodology has been developed in which information from several sophisticated techniques is combined and analysed at a microregional level. First, tumour oxygen availability is spatially defined by measuring intravascular blood oxygen saturations (HbO2) cryospectrophotometrically in frozen tumour blocks. Second, hypoxic development is quantified in adjace...

  13. Renal Blood Oxygenation Level-dependent Imaging in Longitudinal Follow-up of Donated and Remaining Kidneys.

    Science.gov (United States)

    Seif, Maryam; Eisenberger, Ute; Binser, Tobias; Thoeny, Harriet C; Krauer, Fabienne; Rusch, Aurelia; Boesch, Chris; Vogt, Bruno; Vermathen, Peter

    2016-06-01

    Purpose To determine renal oxygenation changes associated with uninephrectomy and transplantation in both native donor kidneys and transplanted kidneys by using blood oxygenation level-dependent (BOLD) MR imaging. Materials and Methods The study protocol was approved by the local ethics committee. Thirteen healthy kidney donors and their corresponding recipients underwent kidney BOLD MR imaging with a 3-T imager. Written informed consent was obtained from each subject. BOLD MR imaging was performed in donors before uninephrectomy and in donors and recipients 8 days, 3 months, and 12 months after transplantation. R2* values, which are inversely related to tissue partial pressure of oxygen, were determined in the cortex and medulla. Longitudinal R2* changes were statistically analyzed by using repeated measures one-way analysis of variance with post hoc pair-wise comparisons. Results R2* values in the remaining kidneys significantly decreased early after uninephrectomy in both the medulla and cortex (P oxygen content. In donors, R2* remained significantly decreased in both the medulla and cortex at 3 (P < .01) and 12 (P < .01) months. In transplanted kidneys, R2* remained stable during the first year after transplantation, with no significant change. Among donors, cortical R2* was found to be negatively correlated with estimated glomerular filtration rate (R = -0.47, P < .001). Conclusion The results suggest that BOLD MR imaging may potentially be used to monitor renal functional changes in both remaining and corresponding transplanted kidneys. (©) RSNA, 2016. PMID:26744926

  14. Low Cerebral Oxygen Consumption and Blood Flow in Patients With Cirrhosis and an Acute Episode of Hepatic Encephalopathy

    DEFF Research Database (Denmark)

    Iversen, Peter; Bak, Lasse Kristoffer; Waagepetersen, Helle Sønderby;

    2009-01-01

    (15)O-water PET in 6 patients with liver cirrhosis and an acute episode of overt HE, 6 cirrhotic patients without HE, and 7 healthy subjects. RESULTS: Neither whole-brain CMRO(2) nor CBF differed significantly between cirrhotic patients without HE and healthy subjects, but were both significantly...... reductions in CMRO(2) and CBF in patients with HE were essentially generalized throughout the brain. CONCLUSIONS: The observations imply that reduced cerebral oxygen consumption and blood flow in cirrhotic patients with an acute episode of overt HE are associated with HE and not cirrhosis as such, and that...

  15. The whole blood oxygen binding properties of a large but presumably sluggish polar elasmobranch, the Greenland shark Somniosus microcephalus

    DEFF Research Database (Denmark)

    Steffensen, John Fleng

    2012-01-01

    Australian and New Zealand Society for Comparative Physiology and Biochemistry. Auckland, N.Z., December 2012. Herbert, N.A.1, Skov, p.V.l, Tirsgaard, B.z and Steffensen, J.F. Z Only a few species of elasmobranch live in cold polar waters and the Greenland shark (Somniosus microcephalus) is the...... most notable example. These extremely large and long-lived sharks are thought to be sluggish but their active hunting lifestyle has recently been questioned by the finding of mobile prey species in their stomach (i.e. squid, fish and seal). The whole blood oxygen binding property of S. microcephalus...

  16. Megalophallus as a sequela of priapism in sickle cell anemia: use of blood oxygen level-dependent magnetic resonance imaging.

    Science.gov (United States)

    Kassim, A A; Umans, H; Nagel, R L; Fabry, M E

    2000-09-01

    Priapism is a common complication of sickle cell anemia. We report a little known sequela of priapism: painless megalophallus, with significant penile enlargement. The patient had had an intense episode of priapism 9 years previously and his penis remained enlarged. Blood oxygen level-dependent magnetic resonance imaging revealed enlarged, hypoxic corpora cavernosa. Megalophallus probably resulted from permanent loss of elasticity of the tunica albuginea due to severe engorgement during the episode of priapism. This sequela needs to be recognized by physicians because no intervention is necessary and sexual function seems to remain intact. PMID:10962334

  17. Acute supplementation of N-acetylcysteine does not affect muscle blood flow and oxygenation characteristics during handgrip exercise.

    Science.gov (United States)

    Smith, Joshua R; Broxterman, Ryan M; Ade, Carl J; Evans, Kara K; Kurti, Stephanie P; Hammer, Shane M; Barstow, Thomas J; Harms, Craig A

    2016-04-01

    N-acetylcysteine (NAC; antioxidant and thiol donor) supplementation has improved exercise performance and delayed fatigue, but the underlying mechanisms are unknown. One possibility isNACsupplementation increases limb blood flow during severe-intensity exercise. The purpose was to determine ifNACsupplementation affected exercising arm blood flow and muscle oxygenation characteristics. We hypothesized thatNACwould lead to higher limb blood flow and lower muscle deoxygenation characteristics during severe-intensity exercise. Eight healthy nonendurance trained men (21.8 ± 1.2 years) were recruited and completed two constant power handgrip exercise tests at 80% peak power until exhaustion. Subjects orally consumed either placebo (PLA) orNAC(70 mg/kg) 60 min prior to handgrip exercise. Immediately prior to exercise, venous blood samples were collected for determination of plasma redox balance. Brachial artery blood flow (BABF) was measured via Doppler ultrasound and flexor digitorum superficialis oxygenation characteristics were measured via near-infrared spectroscopy. FollowingNACsupplementaiton, plasma cysteine (NAC: 47.2 ± 20.3 μmol/L vs.PLA: 9.6 ± 1.2 μmol/L;P = 0.001) and total cysteine (NAC: 156.2 ± 33.9 μmol/L vs.PLA: 132.2 ± 16.3 μmol/L;P = 0.048) increased. Time to exhaustion was not significantly different (P = 0.55) betweenNAC(473.0 ± 62.1 sec) andPLA(438.7 ± 58.1 sec). RestingBABFwas not different (P = 0.79) withNAC(99.3 ± 31.1 mL/min) andPLA(108.3 ± 46.0 mL/min).BABFwas not different (P = 0.42) during exercise or at end-exercise (NAC: 413 ± 109 mL/min;PLA: 445 ± 147 mL/min). Deoxy-[hemoglobin+myoglobin] and total-[hemoglobin+myoglobin] were not significantly different (P = 0.73 andP = 0.54, respectively) at rest or during exercise between conditions. We conclude that acuteNACsupplementation does not alter oxygen delivery during exercise in men. PMID:27044854

  18. The effects of graded changes in oxygen and carbon dioxide tension on coronary blood velocity independent of myocardial energy demand.

    Science.gov (United States)

    Boulet, Lindsey M; Stembridge, Mike; Tymko, Michael M; Tremblay, Joshua C; Foster, Glen E

    2016-08-01

    In humans, coronary blood flow is tightly regulated by microvessels within the myocardium to match myocardial energy demand. However, evidence regarding inherent sensitivity of the microvessels to changes in arterial partial pressure of carbon dioxide and oxygen is conflicting because of the accompanied changes in myocardial energy requirements. This study aimed to investigate the changes in coronary blood velocity while manipulating partial pressures of end-tidal CO2 (Petco2) and O2 (Peto2). It was hypothesized that an increase in Petco2 (hypercapnia) or decrease in Peto2 (hypoxia) would result in a significant increase in mean blood velocity in the left anterior descending artery (LADVmean) due to an increase in both blood gases and energy demand associated with the concomitant cardiovascular response. Cardiac energy demand was assessed through noninvasive measurement of the total left ventricular mechanical energy. Healthy subjects (n = 13) underwent a euoxic CO2 test (Petco2 = -8, -4, 0, +4, and +8 mmHg from baseline) and an isocapnic hypoxia test (Peto2 = 64, 52, and 45 mmHg). LADVmean was assessed using transthoracic Doppler echocardiography. Hypercapnia evoked a 34.6 ± 8.5% (mean ± SE; P < 0.01) increase in mean LADVmean, whereas hypoxia increased LADVmean by 51.4 ± 8.8% (P < 0.05). Multiple stepwise regressions revealed that both mechanical energy and changes in arterial blood gases are important contributors to the observed changes in LADVmean (P < 0.01). In summary, regulation of the coronary vasculature in humans is mediated by metabolic changes within the heart and an inherent sensitivity to arterial blood gases. PMID:27233761

  19. Independent component analysis applied to pulse oximetry in the estimation of the arterial oxygen saturation (SpO2) - a comparative study

    DEFF Research Database (Denmark)

    Jensen, Thomas; Duun, Sune Bro; Larsen, Jan; Haahr, Rasmus Grønbek; Toft, M. H.; Belhage, B.; Thomsen, Erik Vilain

    2009-01-01

    ), and Mean Field ICA (ICAMF). The signal processing includes pre-processing bandpass filtering to eliminate noise, and post-processing by calculating the SpO2. The algorithms are compared to the commercial state-of-the-art algorithm Discrete Saturation Transform (DST) by Masimo Corporation. It is...

  20. Calculating acid-base and oxygenation status during COPD exacerbation using mathematically arterialised venous blood

    DEFF Research Database (Denmark)

    Rees, Stephen Edward; Rychwicka-Kielek, Beate A; Andersen, Bjarne F;

    2012-01-01

    Abstract Background: Repeated arterial puncture is painful. A mathematical method exists for transforming peripheral venous pH, PCO2 and PO2 to arterial eliminating the need for arterial sampling. This study evaluates this method to monitor acid-base and oxygenation during admission for exacerbat......Abstract Background: Repeated arterial puncture is painful. A mathematical method exists for transforming peripheral venous pH, PCO2 and PO2 to arterial eliminating the need for arterial sampling. This study evaluates this method to monitor acid-base and oxygenation during admission...

  1. 联合脉搏血氧监测法评估急性卒中误吸风险临床价值研究%Water swallow test associated with oxygen saturation monitoring in accessing aspiration after acute stroke.

    Institute of Scientific and Technical Information of China (English)

    李巍; 孟然; 李占元; 张彤

    2011-01-01

    Objective To evaluate the value of water swallow test associated with oxygen saturation monitoring in accessing aspiration after acute stroke. Methods 117 acute stroke patients admitted to our hospital between April 2005 and July 2007 were enrolled. The risk of aspiration in the 117 patients was assessed with the routine method (cranial nerve examination,water swallow test) and the combination of water swallow test and oxygen saturation monitoring (cranial nerve examination, the combination of water swallow test and oxygen saturation monitoring) within 24 hours on admission. Results 47 cases (40. 2% ) were with aspiration risk in the combination of water swallow test and oxygen saturation monitoring; while 25 cases (21. 4% ) were noted with aspiration risk under the routine method; this indicates that the ratio of aspiration risk achieved by combination method was significantly higher than the routine method ( P < 0. 001). The sensitivity on predicting aspiration pneumonia in the combination of water swallow test and oxygen saturation monitoring method was 82. 4% , and that of the routine method was 41. 2% .statistical significance of sensitivity was noted between both methods {P =0. 001). Conclusion Combination of water swallow test and oxygen saturation monitoring may be used in evaluating the aspiration risk and aspiration pneumonitis of patients with stroke.%目的 探讨联合脉搏血氧监测法对急性卒中误吸风险的评估价值.方法 选择2005年4月至2007年7月首都医科大学附属北京世纪坛医院连续收治的急性脑卒中患者117例.急性脑卒中患者入院后24 h内分别按普通检查法(颅神经检查和洼田饮水试验)及联合脉搏血氧监测法(颅神经检查、洼田饮水试验联合同步的脉搏血氧监测法)评估患者的误吸风险.结果 联合脉搏血氧监测法发现存在误吸风险的患者47例(40.2%),常规检查法为25例(21.4%),该方法评估误吸风险的比率

  2. Influence of residual oxygen-15-labeled carbon monoxide radioactivity on cerebral blood flow and oxygen extraction fraction in a dual-tracer autoradiographic method

    International Nuclear Information System (INIS)

    Cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), oxygen extraction fraction (OEF), and cerebral blood volume (CBV) are quantitatively measured with positron emission tomography (PET) with 15O gases. Kudomi et al. developed a dual tracer autoradiographic (DARG) protocol that enables the duration of a PET study to be shortened by sequentially administrating 15O2 and C15O2 gases. In this protocol, before the sequential PET scan with 15O2 and C15O2 gases (15O2-C15O2 PET scan), a PET scan with C15O should be preceded to obtain CBV image. C15O has a high affinity for red blood cells and a very slow washout rate, and residual radioactivity from C15O might exist during a 15O2-C15O2 PET scan. As the current DARG method assumes no residual C15O radioactivity before scanning, we performed computer simulations to evaluate the influence of the residual C15O radioactivity on the accuracy of measured CBF and OEF values with DARG method and also proposed a subtraction technique to minimize the error due to the residual C15O radioactivity. In the simulation, normal and ischemic conditions were considered. The 15O2 and C15O2 PET count curves with the residual C15O PET counts were generated by the arterial input function with the residual C15O radioactivity. The amounts of residual C15O radioactivity were varied by changing the interval between the C15O PET scan and 15O2-C15O2 PET scan, and the absolute inhaled radioactivity of the C15O gas. Using the simulated input functions and the PET counts, the CBF and OEF were computed by the DARG method. Furthermore, we evaluated a subtraction method that subtracts the influence of the C15O gas in the input function and PET counts. Our simulations revealed that the CBF and OEF values were underestimated by the residual C15O radioactivity. The magnitude of this underestimation depended on the amount of C15O radioactivity and the physiological conditions. This underestimation was corrected by the subtraction method. This

  3. Effect of cold rolling on the oxidation resistance of T91 steel in oxygen-saturated stagnant liquid lead-bismuth eutectic at 450 °C and 550 °C

    Science.gov (United States)

    Dong, Hong; Ye, Zhongfei; Wang, Pei; Li, Dianzhong; Zhang, Yutuo; Li, Yiyi

    2016-08-01

    The compatibility of T91 steels having different preparation processes with oxygen-saturated stagnant lead-bismuth eutectic have been investigated at 450 °C and 550 °C. It is found that cold rolling decreases the thickness of the oxide scale of T91 steel by forming a continuous enhanced Cr-rich belt in the inner oxide layer next to the internal oxidation zone, which is attributed to the rapid diffusion of Cr induced by numerous non-equilibrium grain boundaries and migrating dislocations.

  4. Muscle tissue saturation in humans studied with two non-invasive optical techniques: a comparative study

    Science.gov (United States)

    Shaharin, Alfi; Krite Svanberg, Emilie; Ellerström, Ida; Subash, Arman Ahamed; Khoptyar, Dmitry; Andersson-Engels, Stefan; Åkeson, Jonas

    2013-11-01

    Muscle tissue saturation (StO2) has been measured with two non-invasive optical techniques and the results were compared. One of the techniques is widely used in the hospitals - the CW-NIRS technique. The other is the photon timeof- flight spectrometer (pTOFS) developed in the Group of Biophotonics, Lund University, Sweden. The wavelengths used in both the techniques are 730 nm and 810 nm. A campaign was arranged to perform measurements on 21 (17 were taken for comparison) healthy adult volunteers (8 women and 13 men). Oxygen saturations were measured at the right lower arm of each volunteer. To observe the effects of different provocations on the oxygen saturation a blood pressure cuff was attached in the upper right arm. For CW-NIRS, the tissue saturation values were in the range from 70-90%, while for pTOFS the values were in the range from 55-60%.

  5. Blood flow and oxygenation changes due to low-frequency repetitive transcranial magnetic stimulation of the cerebral cortex

    Science.gov (United States)

    Mesquita, Rickson C.; Faseyitan, Olufunsho K.; Turkeltaub, Peter E.; Buckley, Erin M.; Thomas, Amy; Kim, Meeri N.; Durduran, Turgut; Greenberg, Joel H.; Detre, John A.; Yodh, Arjun G.; Hamilton, Roy H.

    2013-06-01

    Transcranial magnetic stimulation (TMS) modulates processing in the human brain and is therefore of interest as a treatment modality for neurologic conditions. During TMS administration, an electric current passing through a coil on the scalp creates a rapidly varying magnetic field that induces currents in the cerebral cortex. The effects of low-frequency (1 Hz), repetitive TMS (rTMS) on motor cortex cerebral blood flow (CBF) and tissue oxygenation in seven healthy adults, during/after 20 min stimulation, is reported. Noninvasive optical methods are employed: diffuse correlation spectroscopy (DCS) for blood flow and diffuse optical spectroscopy (DOS) for hemoglobin concentrations. A significant increase in median CBF (33%) on the side ipsilateral to stimulation was observed during rTMS and persisted after discontinuation. The measured hemodynamic parameter variations enabled computation of relative changes in cerebral metabolic rate of oxygen consumption during rTMS, which increased significantly (28%) in the stimulated hemisphere. By contrast, hemodynamic changes from baseline were not observed contralateral to rTMS administration (all parameters, p>0.29). In total, these findings provide new information about hemodynamic/metabolic responses to low-frequency rTMS and, importantly, demonstrate the feasibility of DCS/DOS for noninvasive monitoring of TMS-induced physiologic effects.

  6. Cerebral blood flow and oxygen metabolism in senile dementia of Alzheimer's type and vascular dementia with deep white matter changes

    International Nuclear Information System (INIS)

    Regional cerebral blood flow (rCBF), cerebral metabolic rate of oxygen (rCMRO2), oxygen extraction fraction (rOEF), and cerebral blood volume (rCBV) were investigated using positron emission tomography (PET) in 16 patients with senile dementia of Alzheimer's type (SDAT), and compared with those of 6 nondemented and 3 demented patients with deep white matter high signal (DWMH) on T2-weighted MRI and 6 controls. rCBF, rCMRO2 and rCBV were determined using C15O2, 15O2 and C15O, respectively. rCBF and CMRO2 were significantly decreased in the frontal, parietal and temporal cortex (P 2 was significantly reduced in only the frontal and temporal cortex of demented patients (P < 0.05). rOEF was significantly increased in the parietal cortex of patients with SDAT and in the white matter of patients with SDAT or DWMH (P < 0.05), and the increase in the frontal white matter significantly paralleled the progression of dementia in patients with SDAT (P < 0.05). rCBV was significantly decreased in the parietal and temporal cortex of patients with SDAT (P < 0.05), but not in any areas of those with DWMH. (orig.)

  7. Replacing the Transfusion of 1–2 Units of Blood with Plasma Expanders that Increase Oxygen Delivery Capacity: Evidence from Experimental Studies

    Directory of Open Access Journals (Sweden)

    Amy G. Tsai

    2014-10-01

    Full Text Available At least a third of the blood supply in the world is used to transfuse 1–2 units of packed red blood cells for each intervention and most clinical trials of blood substitutes have been carried out at this level of oxygen carrying capacity (OCC restoration. However, the increase of oxygenation achieved is marginal or none at all for molecular hemoglobin (Hb products, due to their lingering vasoactivity. This has provided the impetus for the development of “oxygen therapeutics” using Hb-based molecules that have high oxygen affinity and target delivery of oxygen to anoxic areas. However it is still unclear how these oxygen carriers counteract or mitigate the functional effects of anemia due to obstruction, vasoconstriction and under-perfusion. Indeed, they are administered as a low dosage/low volume therapeutic Hb (subsequently further diluted in the circulatory pool and hence induce extremely small OCC changes. Hyperviscous plasma expanders provide an alternative to oxygen therapeutics by increasing the oxygen delivery capacity (ODC; in anemia they induce supra-perfusion and increase tissue perfusion (flow by as much as 50%. Polyethylene glycol conjugate albumin (PEG-Alb accomplishes this by enhancing the shear thinning behavior of diluted blood, which increases microvascular endothelial shear stress, causes vasodilation and lowering peripheral vascular resistance thus facilitating cardiac function. Induction of supra-perfusion takes advantage of the fact that ODC is the product of OCC and blood flow and hence can be maintained by increasing either or both. Animal studies suggest that this approach may save a considerable fraction of the blood supply. It has an additional benefit of enhancing tissue clearance of toxic metabolites.

  8. Relationship of efficiency indices with performance, heart rate, oxygen consumption, blood parameters, and estimated heat production in Nellore steers.

    Science.gov (United States)

    Chaves, A S; Nascimento, M L; Tullio, R R; Rosa, A N; Alencar, M M; Lanna, D P

    2015-10-01

    The objective of this study was to examine the relationship of efficiency indices with performance, heart rate, oxygen consumption, blood parameters, and estimated heat production (EHP) in Nellore steers. Eighteen steers were individually lot-fed diets of 2.7 Mcal ME/kg DM for 84 d. Estimated heat production was determined using oxygen pulse (OP) methodology, in which heart rate (HR) was monitored for 4 consecutive days. Oxygen pulse was obtained by simultaneously measuring HR and oxygen consumption during a 10- to 15-min period. Efficiency traits studied were feed efficiency (G:F) and residual feed intake (RFI) obtained by regression of DMI in relation to ADG and midtest metabolic BW (RFI). Alternatively, RFI was also obtained based on equations reported by the NRC's to estimate individual requirement and DMI (RFI calculated by the NRC [1996] equation [RFI]). The slope of the regression equation and its significance was used to evaluate the effect of efficiency indices (RFI, RFI, or G:F) on the traits studied. A mixed model was used considering RFI, RFI, or G:F and pen type as fixed effects and initial age as a covariate. For HR and EHP variables, day was included as a random effect. There was no relationship between efficiency indices and back fat depth measured by ultrasound or daily HR and EHP ( > 0.05). Because G:F is obtained in relation to BW, the slope of G:F was positive and significant ( RFI and RFI ( RFI. Oxygen consumption per beat was not related to G:F; however, it was lower for RFI- and RFI-efficient steers, and consequently, oxygen volume (mL·min·kg) and OP (μL O·beat·kg) were also lower ( RFI and RFI ( > 0.05); however, G:F-efficient steers showed lower hematocrit and hemoglobin concentrations ( < 0.05). Differences in EHP between efficient and inefficient animals were not directly detected. Nevertheless, differences in oxygen consumption and OP were detected, indicating that the OP methodology may be useful to predict growth efficiency. PMID

  9. Effects of acetazolamide on cerebral blood flow and brain tissue oxygenation

    DEFF Research Database (Denmark)

    Lassen, N A; Friberg, L; Kastrup, J;

    1987-01-01

    Oral administration of 1 g of acetazolamide to 8 normal subjects studied at sea level and in normoxia caused an acute increase in cerebral blood flow (CBF). During the subsequent prolonged oral treatment with 1 g of acetazolamide daily, CBF returned to normal within 2 days. The alveolar CO2 tensi...

  10. Average blood flow and oxygen uptake in the human brain during resting wakefulness

    DEFF Research Database (Denmark)

    Madsen, P L; Holm, S; Herning, M; Lassen, N A

    1993-01-01

    tracer between the brain and its venous blood is not reached. As a consequence, normal values for CBF and CMRO2 of 54 ml 100 g-1 min-1 and 3.5 ml 100 g-1 min-1 obtained with the Kety-Schmidt technique are an overestimation of the true values. Using the Kety-Schmidt technique we have performed 57...

  11. Early outcome and blood-brain barrier integrity after co-administered thrombolysis and hyperbaric oxygenation in experimental stroke

    Directory of Open Access Journals (Sweden)

    Michalski Dominik

    2011-06-01

    Full Text Available Abstract Background After promising results in experimental stroke, normobaric (NBO or hyperbaric oxygenation (HBO have recently been discussed as co-medication with tissue plasminogen activator (tPA for improving outcome. This study assessed the interactions of hyperoxia and tPA, focusing on survival, early functional outcome and blood-brain barrier (BBB integrity following experimental stroke. Methods Rats (n = 109 underwent embolic middle cerebral artery occlusion or sham surgery. Animals were assigned to: Control, NBO (60-minute pure oxygen, HBO (60-minute pure oxygen at 2.4 absolute atmospheres, tPA, or HBO+tPA. Functional impairment was assessed at 4 and 24 hours using Menzies score, followed by intravenous application of FITC-albumin as a BBB permeability marker, which was allowed to circulate for 1 hour. Further, blood sampling was performed at 5 and 25 hours for MMP-2, MMP-9, TIMP-1 and TIMP-2 concentration. Results Mortality rates did not differ significantly between groups, whereas functional improvement was found for NBO, tPA and HBO+tPA. NBO and HBO tended to stabilize BBB and to reduce MMP-2. tPA tended to increase BBB permeability with corresponding MMP and TIMP elevation. Co-administered HBO failed to attenuate these early deleterious effects, independent of functional improvement. Conclusions The long-term consequences of simultaneously applied tPA and both NBO and HBO need to be addressed by further studies to identify therapeutic potencies in acute stroke, and to avoid unfavorable courses following combined treatment.

  12. One-legged endurance training: leg blood flow and oxygen extraction during cycling exercise

    DEFF Research Database (Denmark)

    Rud, B; Foss, O; Krustrup, Peter; Secher, Niels H.; Hallén, J

    2012-01-01

    Aim: As a consequence of enhanced local vascular conductance, perfusion of muscles increases with exercise intensity to suffice the oxygen demand. However, when maximal oxygen uptake (VO(2) max) and cardiac output are approached, the increase in conductance is blunted. Endurance training increases...... muscle metabolic capacity, but to what extent that affects the regulation of muscle vascular conductance during exercise is unknown. Methods: Seven weeks of one-legged endurance training was carried out by twelve subjects. Pulmonary VO(2) during cycling and one-legged cycling was tested before and after...... training, while VO(2) of the trained leg (TL) and control leg (CL) during cycling was determined after training. Results: VO(2) max for cycling was unaffected by training, although one-legged VO(2) max became 6.7 (2.3)% (mean ± SE) larger with TL than with CL. Also TL citrate synthase activity was higher...

  13. Retinal oxygen extraction in humans

    Science.gov (United States)

    Werkmeister, René M.; Schmidl, Doreen; Aschinger, Gerold; Doblhoff-Dier, Veronika; Palkovits, Stefan; Wirth, Magdalena; Garhöfer, Gerhard; Linsenmeier, Robert A.; Leitgeb, Rainer A.; Schmetterer, Leopold

    2015-01-01

    Adequate function of the retina is dependent on proper oxygen supply. In humans, the inner retina is oxygenated via the retinal circulation. We present a method to calculate total retinal oxygen extraction based on measurement of total retinal blood flow using dual-beam bidirectional Doppler optical coherence tomography and measurement of oxygen saturation by spectrophotometry. These measurements were done on 8 healthy subjects while breathing ambient room air and 100% oxygen. Total retinal blood flow was 44.3 ± 9.0 μl/min during baseline and decreased to 18.7 ± 4.2 μl/min during 100% oxygen breathing (P < 0.001) resulting in a pronounced decrease in retinal oxygen extraction from 2.33 ± 0.51 μl(O2)/min to 0.88 ± 0.14 μl(O2)/min during breathing of 100% oxygen. The method presented in this paper may have significant potential to study oxygen metabolism in hypoxic retinal diseases such as diabetic retinopathy. PMID:26503332

  14. Probing Brain Oxygenation with Near Infrared spectroscopy, the Role of Carbon Dioxide and Blood Pressure

    CERN Document Server

    Gersten, Alexander

    2015-01-01

    The fundamentals of near infrared spectroscopy (NIRS) are reviewed. Among the major factors controlling the cerebral blood flow (CBF), the effect of PaCO2 is peculiar in that it violates autoregulatory CBF mechanisms and allows to explore the full range of the CBF. A simple physical model, with a four parameter formula, relating the CBF to PaCO2 is presented. It can be used to transform the fits of one animal to the fits of another one. It enable the use of rats data as monkeys data simply by rescaling the PaCO2 values and the CBF data. Controlled breathing can change the PaCO2. Experiments on human subjects relating the PaCO2 to rSO2, measured with brain oximeters, are presented. A simple model relating the mean blood pressure to CBF is worked out.

  15. Embryonic mouse blood flow and oxygen correlate with early pancreatic differentiation

    OpenAIRE

    Shah, Sohail R.; ESNI, FARZAD; Jakub, Adam; Paredes, Jose; Lath, Nikesh; Malek, Marcus; Potoka, Douglas A.; Prasadan, Krishna; Mastroberardino, Pier G.; Shiota, Chiyo; Guo, Ping; Miller, Kelly A.; Hackam, David J.; Burns, R. Cartland; Tulachan, Sidhartha S.

    2010-01-01

    The mammalian embryo represents a fundamental paradox in biology. Its location within the uterus, especially early during development when embryonic cardiovascular development and placental blood flow are not well-established, leads to an obligate hypoxic environment. Despite this hypoxia, the embryonic cells are able to undergo remarkable growth, morphogenesis, and differentiation. Recent evidence suggests that embryonic organ differentiation, including pancreatic β-cells, is tightly regulat...

  16. The association between forced expiratory volume in one second (FEV1 and pulse oximetric measurements of arterial oxygen saturation (SpO2 in the patients with COPD: A preliminary study

    Directory of Open Access Journals (Sweden)

    Mohammad Emami Ardestani

    2014-01-01

    Full Text Available Background: The study was aimed to explore the association between arterial oxygen saturation (SpO2 and spirometer parameters of disease severity in chronic obstructive pulmonary disease (COPD patients with a view to identify whether the pulse oximetry can be used as an alternative to arterial values in the clinical management of COPD patients in a routine practice. Materials and Methods: Thirty-one patients with COPD were included in this study. After evaluation of each patient through history taking, physical examination and chest X-ray, SpO2 % and data regarding spirometry (FEV1% predicted and FEV1/FVC % predicted in all patients were measured. Linear correlations among the variables were analyzed using the regression analysis. Results: In total 31 COPD patients according to the criteria established by the Global Initiative for Chronic Obstructive Disease (GOLD were included in the study. There was not statistically significant correlation between FEV1 % predicted and SpO2 values (P > 0.05, but a great correlation existed between FEV1/FVC % predicted and SpO2 values (r = 0.556, P < 0.001. Median SpO2 values did not differ between GOLD stages (Kruskal-Wallis test: P = 0.17. Conclusion: The study may demonstrate that oxygen saturation measured by pulse oximetry appears to be independent of the degree of airways obstruction as quantified by the FEV1; although further evidence needs to be assessed these preliminary findings.

  17. Comparison of cerebral oxygen saturation in premature infants by near-infrared spatially resolved spectroscopy: observations on probe-dependent bias

    DEFF Research Database (Denmark)

    Sorensen, Line C; Leung, Terence S; Greisen, Gorm

    2008-01-01

    oxygenation index (c-TOI) was measured using NIRO 300 (Hamamatsu Photonics KK). c-TOI was measured at several positions in each infant. c-TOI varied over time, increasing in the first third and decreasing in the last third of the study period (p<10(-6)). Two probes were used in the study, and a highly...

  18. Oxygen administration in the care of neonates: a double-edged sword

    Institute of Scientific and Technical Information of China (English)

    Phyllis A. Dennery

    2010-01-01

    Objective To evaluate the use of oxygen in neonates in the past, present and future Data sources The data are mainly from Pubmed with relevant published articles from the 1940s to the present with some information gathered from web searches.Study selection Studies evaluating the use of oxygen in premature and term infants through history with original milestone articles included.Results There are still many unknowns about the proper use of oxygen in preterm and term infants but many studies suggest that both liberal use (resulting in a blood oxygen saturation of greater than 94%) as well as restrictive use (resulting in a blood oxygen saturation of less than 80%-85%) are detrimental and have long term consequences on the infant.Conclusions Definitive studies evaluating the appropriate concentration and duration of supplemental oxygen are ongoing and will help in the management of term and preterm infants requiring oxygen.

  19. Measurement of local blood flow and oxygen consumption in evolving irreversible cerebral infarction: an in vivo study in man

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) allows in vivo measurement of local cerebral blood flow (1CBF), oxygen consumption rate (1CMRO2) and glucose utilisation (1CMRG1c) in man. Although 1CMRG1c is accessible in animals, this is not the case for 1CMRO2, an excellent index of local functional state. PET imaging of the local interrelationship of CBF and metabolism in completed ischemic stroke has attracted considerable interest because of its potential to differentiate irreversibly damaged from viable tissue on the basis of the CBF- metabolism patterns. Several qualitative or semi-quantitative pioneering studies provided a limited insight into this question, while the single truly quantitative study was only briefly reported. We report here a detailed study of the local CBF-CMRO2 quantitative patterns in irreversibly infarcted brain regions

  20. Increased regional homogeneity of blood oxygen level-dependent signals in occipital cortex of early blind individuals.

    Science.gov (United States)

    Liu, Chong; Liu, Yong; Li, Weilan; Wang, Dawei; Jiang, Tianzi; Zhang, Yunting; Yu, Chunshui

    2011-03-01

    Although resting-state functional magnetic resonance imaging has shown altered functional connectivity between visual and other brain areas in the early blind individuals, it cannot answer which brain area's local activities are changed. In this study, regional homogeneity, a measure of the homogeneity of the local blood oxygen level-dependent signals, was used for the first time to investigate the changes in the resting-state brain activity in the early blind individuals. Compared with age-matched and sex-matched sighted individuals, the early blind individuals showed increased regional homogeneity only in the occipital areas, which might be explained by the abnormal cortical development and/or experience-dependent plasticity, resulted from an early visual deprivation. PMID:21304328

  1. Cerebral misery perfusion diagnosed using hypercapnic blood-oxygenation-level-dependent contrast functional magnetic resonance imaging: a case report

    Directory of Open Access Journals (Sweden)

    D'Souza Olympio

    2010-02-01

    Full Text Available Abstract Introduction Cerebral misery perfusion represents a failure of cerebral autoregulation. It is an important differential diagnosis in post-stroke patients presenting with collapses in the presence of haemodynamically significant cerebrovascular stenosis. This is particularly the case when cortical or internal watershed infarcts are present. When this condition occurs, further investigation should be done immediately. Case presentation A 50-year-old Caucasian man presented with a stroke secondary to complete occlusion of his left internal carotid artery. He went on to suffer recurrent seizures. Neuroimaging demonstrated numerous new watershed-territory cerebral infarcts. No source of arterial thromboembolism was demonstrable. Hypercapnic blood-oxygenation-level-dependent-contrast functional magnetic resonance imaging was used to measure his cerebrovascular reserve capacity. The findings were suggestive of cerebral misery perfusion. Conclusions Blood-oxygenation-level-dependent-contrast functional magnetic resonance imaging allows the inference of cerebral misery perfusion. This procedure is cheaper and more readily available than positron emission tomography imaging, which is the current gold standard diagnostic test. The most evaluated treatment for cerebral misery perfusion is extracranial-intracranial bypass. Although previous trials of this have been unfavourable, the results of new studies involving extracranial-intracranial bypass in high-risk patients identified during cerebral perfusion imaging are awaited. Cerebral misery perfusion is an important and under-recognized condition in which emerging imaging and treatment modalities present the possibility of practical and evidence-based management in the near future. Physicians should thus be aware of this disorder and of recent developments in diagnostic tests that allow its detection.

  2. Fiberoptic monitoring of central venous oxygen saturation (PediaSat in small children undergoing cardiac surgery: continuous is not continuous [v3; ref status: indexed, http://f1000r.es/3qt

    Directory of Open Access Journals (Sweden)

    Francesca G. Iodice

    2014-06-01

    Full Text Available Background: Monitoring of superior vena cava saturation (ScvO2 has become routine in the management of pediatric patients undergoing cardiac surgery. The objective of our study was to evaluate the correlation between continuous ScvO2 by the application of a fiber-optic oximetry catheter (PediaSat and intermittent ScvO2 by using standard blood gas measurements. These results were compared to those obtained by cerebral near infrared spectroscopy (cNIRS. Setting: Tertiary pediatric cardiac intensive care unit (PCICU. Methods and main results: A retrospective study was conducted in consecutive patients who were monitored with a 4.5 or 5.5 F PediaSat catheter into the right internal jugular vein. An in vivo calibration was performed once the patient was transferred to the PCICU and re-calibration took place every 24 hours thereafter. Each patient had a NIRS placed on the forehead. Saturations were collected every 4 hours until extubation. Ten patients with a median age of 2.2 (0.13-8.5 years and a weight of 12.4 (3.9-24 kg were enrolled. Median sampling time was 32 (19-44 hours: 64 pairs of PediaSat and ScVO2 saturations showed a poor correlation (r=0.62, 95% CI 44-75; p<0.0001 and Bland Altman analysis for repeated measures showed an average difference of 0.34 with a standard deviation of 7,9 and 95% limits of agreement from -15 to 16. Thirty-six pairs of cNIRS and ScVO2 saturations showed a fair correlation (r=0.79, 95% CI 0.60-0.89; p<0.0001 an average difference of -1.4 with a standard deviation of 6 and 95% limits of agreement from -13 to 10. Analysis of median percentage differences between PediaSat and ScvO2 saturation over time revealed that, although not statistically significant, the change in percentage saturation differences was clinically relevant after the 8th hour from calibration (from -100 to +100%. Conclusion: PediaSat catheters showed unreliable performance in our cohort. It should be further investigated whether repeating

  3. Comparison of the effects of on-pump and off-pump coronary artery bypass surgery on cerebral oxygen saturation using near-infrared spectroscopy

    OpenAIRE

    Demir, Guray; Çukurova, Zafer; Eren, Gülay; Hergünsel, Oya

    2014-01-01

    Background Central nervous system complications are the most clinically important of those affecting mortality in patients undergoing coronary artery surgery. Newly developed sophisticated techniques and surgical interventions obviating the need for cardiopulmonary pumps have facilitated avoidance of these complications. In this study, we compared the impact of on-pump and off-pump coronary artery bypass surgery on cerebral oxygenation using near-infrared spectroscopy. Methods This study incl...

  4. Cerebral tissue oxygenation index and superior vena cava blood flow in the very low birth weight infant.

    LENUS (Irish Health Repository)

    Moran, M

    2012-02-01

    BACKGROUND: Superior vena cava (SVC) flow assesses blood flow from the upper body, including the brain. Near infrared spectroscopy (NIRS) provides information on brain perfusion and oxygenation. AIM: To assess the relationship between cerebral tissue oxygenation index (cTOI) and cardiac output measures in the very low birth weight (VLBW) infant in the first day of life. METHODS: A prospective observational cohort study. Neonates with birth weight less than 1500 g (VLBW) were eligible for enrollment. Newborns with congenital heart disease, major congenital malformations and greater than Papile grade1 Intraventricular Haemorrhage on day 1 of life were excluded. Echocardiographic evaluation of SVC flow was performed in the first 24 h of life. Low SVC flow states were defined as a flow less than 40 mL\\/kg\\/min. cTOI was measured using NIRO 200 Hamamatsu. RESULTS: Twenty-seven VLBW neonates had both echocardiography and NIRS performed. The median (range) gestation was 29\\/40 (25 + 3 to 31 + 5 weeks) and median birth weight was 1.2 kg (0.57-1.48 kg). The mean (SD) TOI was 68.1 (7.9)%. The mean (SD) SVC flow was 70.36(39.5) mLs\\/kg\\/min. The correlation coefficient of cerebral tissue oxygenation and SVC flow was r = 0.53, p-value 0.005. There was a poor correlation between right and left ventricular output and cTOI which is not surprising considering the influence of intra- and extracardiac shunts. CONCLUSION: There is a positive relationship between cerebral TOI values and SVC flow in the very low birth infant on day one of life.

  5. The relationship between the cerebral blood flow, oxygen consumption and glucose metabolism in primary degenerative dementia

    International Nuclear Information System (INIS)

    The CBF, CMRO2 and CMRGlu were measured in patients with primary degenerative dementia including 5 patients with dementia of Alzheimer's type and 4 patients with Pick's disease, and then the correlation between the cerebral blood flow and energy metabolism was evaluated. The control subjects consisted of 5 age-matched normal volunteers. The CBF, CMRO2 and CMRGlu decreased in the bilateral frontal, temporal and parietal regions in the patients with Alzheimer's dementia, while they decreased in the bilateral frontal and temporal regions in the patients with Pick's disease. Both the CBF and CMRO2 were closely correlated with each other. However, the CMRGlu was more severely impaired than the CBF or CMRO2 in both pathological conditions. These results suggested that CMRGlu began to decrease before the reduction of the aerobic metabolism and thus measuring the CMRGlu is considered to be the most sensitive method for detecting abnormal regions in primary degenerative dementia. (author)

  6. MUSCLE METABOLISM WITH BLOOD FLOW RESTRICTION IN CHRONIC FATIGUE SYNDROME

    OpenAIRE

    McCully, Kevin K; Smith, Sinclair; Rajaei, Sheeva; Leigh, John S.; Natelson, Benjamin H

    2003-01-01

    The purpose of this study was to determine if chronic fatigue syndrome (CFS) is associated with reduced blood flow and muscle oxidative metabolism. Patients with CFS according to CDC criteria (n=19) were compared to normal sedentary subjects (n = 11). Muscle blood flow was measured in the femoral artery with Doppler ultrasound after exercise. Muscle metabolism was measured in the medial gastrocnemius muscle using 31P magnetic resonance spectroscopy (MRS). Muscle oxygen saturation and blood vo...

  7. Simultaneous mapping of temporally-resolved blood flow velocity and oxygenation in femoral artery and vein during reactive hyperemia

    Directory of Open Access Journals (Sweden)

    Langham Michael C

    2011-10-01

    Full Text Available Abstract Background Post-occlusive hyperemia is often used as a paradigm to evaluate vascular reactivity, for example by measuring post-ischemic flow-mediated dilation, arterial blood flow or temporally resolved venous blood oxygenation (HbO2. Here we demonstrate the feasibility of a simultaneous measurement of blood flow and HbO2 in the femoral circulation as part of a single procedure. Methods A multi-echo GRE pulse sequence was designed and implemented to collect velocity-encoded projections in addition to full-image echoes for field mapping as a means to quantify intravascular magnetic susceptibility. The method's feasibility was evaluated at 3T in a small pilot study involving two groups of healthy subjects (mean ages 26 ± 1.6 and 59 ± 7.3 years, N = 7 and 5, respectively in terms of six parameters characterizing the time-course of reactive hyperemia and their sensitivity to differentiate age effects. The reproducibility was assessed on two of the seven young healthy subjects with three repeated measurements. Results The physiological parameters agree with those obtained with current methods that quantify either velocity or HbO2 alone. Of the six measures of vascular reactivity, one from each group was significantly different in the two subject groups (p Conclusion The proposed method is able quantify multiple parameters that may lead to more detailed assessment of peripheral vascular reactivity in a single cuff paradigm rather than in separate procedures as required previously, thereby improving measurement efficiency and patient comfort.

  8. Saturated fat (image)

    Science.gov (United States)

    ... saturated fats. Vegetable sources of saturated fat include coconut and palm oils. When looking at a food ... saturated fats. Vegetable sources of saturated fat include coconut and palm oils. When looking at a food ...

  9. Feasibilities of combination of hyperbaric oxygenation, ultraviolet blood irradiation, hemisorption in treating patients with sepsis as a complication of acute inflammatory diseases of abdomen

    International Nuclear Information System (INIS)

    Consideration is given to correlation of efficiency of results of treating patients with sepsis during traditional intensive therapy and during complex treatment, including hemosorption, hyperbaric oxygenation, ultraviolet blood irradiation, based on studying clinical picture, biochemical and immunological indices. Increase of treatment efficiency when using mentioned therapeutic measures, particularly their different combinations, is shown. 69 refs

  10. Distinct alterations in sublingual microcirculatory blood flow and hemoglobin oxygenation in on-pump and off-pump coronary artery bypass graft surgery

    NARCIS (Netherlands)

    B. Atasever; C. Boer; P. Goedhart; J. Biervliet; J. Seyffert; R. Speekenbrink; L. Schwarte; B. de Mol; C. Ince

    2011-01-01

    The authors hypothesized that cardiopulmonary bypass (CPB) (on-pump) is associated with more severe changes in the microcirculatory blood flow and tissue oxygenation as compared with off-pump coronary artery bypass surgery. An observational study. A university hospital and teaching hospital. Patient

  11. A Decrease in Spatially Resolved Near-Infrared Spectroscopy-Determined Frontal Lobe Tissue Oxygenation by Phenylephrine Reflects Reduced Skin Blood Flow

    DEFF Research Database (Denmark)

    Ogoh, Shigehiko; Sato, Kohei; Okazaki, Kazunobu;

    2014-01-01

    BACKGROUND: Spatially resolved near-infrared spectroscopy-determined frontal lobe tissue oxygenation (ScO2) is reduced with administration of phenylephrine, while cerebral blood flow may remain unaffected. We hypothesized that extracranial vasoconstriction explains the effect of phenylephrine on Sc...

  12. Validation of quantitative estimation of tissue oxygen extraction fraction and deoxygenated blood volume fraction in phantom and in vivo experiments by using MRI.

    Science.gov (United States)

    Sedlacik, Jan; Reichenbach, Jürgen R

    2010-04-01

    The blood oxygenation level dependent signal of cerebral tissue can be theoretically derived using a network model formed by randomly oriented infinitely long cylinders. The validation of this model by phantom and in vivo experiments is still an object of research. A network phantom was constructed of solid polypropylene strings immersed in silicone oil, which essentially eliminated the effect of spin diffusion. The volume fraction and magnetic property of the string network was predetermined by independent methods. Ten healthy volunteers were measured for in vivo demonstration. The gradient echo sampled spin echo signal was evaluated with the cylinder network model. We found a strong interdependency between the two network characterizing parameters deoxygenated blood volume and oxygen extraction fraction. Here, different sets of deoxygenated blood volume/oxygen extraction fraction values were able to describe the measured signal equally well. However, by setting one parameter constant to a predetermined value, reasonable estimates of the other parameter were obtained. The same behavior was found for the in vivo demonstration. The signal theory of the cylinder network was validated by a well-characterized phantom. However, the found interdependency that was found between deoxygenated blood volume and oxygen extraction fraction requires an independent estimation of one variable to determine reliable values of the other parameter. PMID:20373392

  13. Effects of breathing a hyperoxic hypercapnic gas mixture on blood oxygenation and vascularity of head-and-neck tumors as measured by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Purpose: For head-and-neck tumors, breathing a hyperoxic hypercapnic gas mixture and administration of nicotinamide has been shown to result in a significantly improved tumor response to accelerated radiotherapy (ARCON, Accelerated Radiotherapy with CarbOgen and Nicotinamide). This may be caused by improved tumor oxygenation, possibly mediated by vascular effects. In this study, both blood oxygenation and vascular effects of breathing a hyperoxic hypercapnic gas mixture (98% O2+2% CO2) were assessed by magnetic resonance imaging (MRI) in patients with head-and-neck tumors. Methods and Materials: Tumor vascularity and oxygenation were investigated by dynamic gadolinium contrast-enhanced MRI and blood oxygen level dependent (BOLD) MRI, respectively. Eleven patients with primary head-and-neck tumors were each measured twice; with and without breathing the hyperoxic hypercapnic gas mixture. Results: BOLD MR imaging revealed a significant increase of the MRI time constant of transverse magnetization decay (T2*) in the tumor during hypercapnic hyperoxygenation, which correlates to a decrease of the deoxyhemoglobin concentration. No changes in overall tumor vascularity were observed, as measured by the gadolinium contrast uptake rate in the tumor. Conclusion: Breathing a hyperoxic hypercapnic gas mixture improves tumor blood oxygenation in patients with head-and-neck tumors, which may contribute to the success of the ARCON therapy

  14. Spontaneous calcium waves in Bergman glia increase with age and hypoxia and may reduce tissue oxygen

    OpenAIRE

    Mathiesen, Claus; Brazhe, Alexey; Thomsen, Kirsten; Lauritzen, Martin

    2012-01-01

    Glial calcium (Ca2+) waves constitute a means to spread signals between glial cells and to neighboring neurons and blood vessels. These waves occur spontaneously in Bergmann glia (BG) of the mouse cerebellar cortex in vivo. Here, we tested three hypotheses: (1) aging and reduced blood oxygen saturation alters wave activity; (2) glial Ca2+ waves change cerebral oxygen metabolism; and (3) neuronal and glial wave activity is correlated. We used two-photon microscopy in the cerebellar cortexes of...

  15. The leveling-off of oxygen uptake is related to blood lactate accumulation. Retrospective study of 94 elite rowers.

    Science.gov (United States)

    Lacour, Jean-René; Messonnier, Laurent; Bourdin, Muriel

    2007-09-01

    To assess whether the ability to demonstrate a plateau in oxygen consumption VO2 could be related to adaptation to exercise, the data obtained over a period of 10 years on 94 elite oarsmen who had participated in annual testing were re-evaluated. The test consisted in an incremental step protocol until volitional exhaustion. VO2, heart rate (HR), blood lactate ([La]b) and respiratory exchange ratio (RER) were measured at each step. The maximal oxygen consumption (VO2max), the power corresponding to VO2maxPamax and the maximal power achieved (Ppeak) were recorded. Thirty-eight oarsmen achieved a VO2 plateau and were designated as Pla; 56 did not and were designed as N-Pla. The Pla and N-Pla VO2max, Pamax and maximal HR values were similar. In comparison with N-Pla, the Pla group displayed a rightward shift of the [La]b versus power curve, accounted for by both the increased percentage of VO2max corresponding to 4 mmol l(-1) and the decreased value of [La]b corresponding to Pamax (P<0.05). Pla oarsmen attained a higher Ppeak expressed as % of Pamax (P<0.05) and also showed better ergometer performance (P<0.05). In a sub-group of 53 oarsmen constituted on the basis of Pamax values close to 400 W, for a given power output, the Pla subjects had significantly lower HR, RER, and [La]b values at each sub-maximal stage of the test. These results suggest that achieving a [Formula: see text] plateau during completion of an incremental step protocol accounts for greater muscle ability to maintain homeostasis during exercise. These differences give the oarsmen an advantage in rowing competitions. PMID:17564723

  16. Rejection of false saturation data in optical pulse-oximeter

    Science.gov (United States)

    Scalise, Lorenzo; Marchionni, Paolo; Carnielli, Virgilio

    2010-04-01

    Pulse oximetry (PO) is a non-invasive medical device used for monitoring of the arterial oxygen saturation (SaO2) and in particular of haemoglobin oxygenation in blood. Oxygen saturation is commonly used in any setting where the patient blood oxygen saturation is unstable, including Neonatal Intensive Care Unit (NICU). The main factor affecting PO's output data is the presence of voluntary or involuntary motion artifacts or imperfect skin-sensor contact. Various methods have been employed to reject motion artifact but have met with little success. The aim of the present work is to propose a novel measurement procedure for real-time monitoring and validation of the oxygen saturation data as measured in standard pulse oxymeter. The procedure should be able to individuate and reject erroneous saturation data due to incorrect transducer-skin contact or motion artifact. In the case of short sequences of rejected SpO2 data (time durationECG (HRECG), the heart rate as measured by the pulse oximeter (HRSAT) and the SpO2 value. In order to remove the erroneous SpO2 values reported in the rough data in coincidence of motion artifact (top, right), we have implemented a specific algorithm which provides at the output a new sequence of SpO2 data (validated SpO2 data). With the aim to "rescue" SpO2 value rejected by the previously presented algorithm, we have implemented an algorithm able to provide the "most-probable" SpO2 values in the case of single rejected values or in the case of short sequences of invalidated data (validated by the use of our method (corresponding to a total time of 16 hr, 8min and 40s). The use of the proposed algorithm aiming to "rescue" data from short sequences of rejected data (validated data of the 2.5%t(equivalent to 8hr, 40 min and 16s), allowing a percent of usable data of the 95.7%. Once implemented in clinic, it could be used to identify the period of the day in which the percent of rejected data increase or correlate this data to clinical

  17. Scientific Opinion on the substantiation of a health claim related to the consumption of 2 g/day of plant stanols (as plant stanol esters as part of a diet low in saturated fat and a two-fold greater reduction in blood LDL-cholesterol concentrations compared to the consumption of a diet low in saturated fat alone pursuant to Article 14 of Regulation (EC No 1924/2006

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA

    2013-04-01

    Full Text Available Following an application from McNeil Nutritionals and Raisio Nutrition Ltd, submitted for authorisation of a health claim pursuant to Article 14 of Regulation (EC No 1924/2006 via the Competent Authority of the United Kingdom, the Panel on Dietetic Products, Nutrition and Allergies (NDA was asked to deliver an opinion on the scientific substantiation of a health claim related to the consumption of 2 g/day of plant stanols (as plant stanol esters as part of a diet low in saturated fat and a two-fold greater reduction in blood LDL-cholesterol concentrations compared to the consumption of a diet low in saturated fat alone. The food that is the subject of the health claim, plant stanol esters, is sufficiently characterised. The applicant provided five human intervention studies for the scientific substantiation of the claim. The Panel notes that the design of the studies submitted did not allow an evaluation of the quantitative effects of diets low in saturated fat per se on blood LDL-cholesterol concentrations. Therefore, the effect of consuming 2 g/day plant stanols as part of a diet low in saturated fat relative to the effect of consuming a diet low in saturated fat alone cannot be determined on a quantitative basis. The Panel considers that the evidence provided by the applicant does not establish that the consumption of 2 g/day of plant stanols (as plant stanol esters as part of a diet low in saturated fat results in a two-fold greater reduction in LDL-cholesterol concentrations compared with consuming a diet low in saturated fat alone. A claim on plant stanol esters and reduction of blood LDL-cholesterol concentrations (irrespective of the background diet has already been authorised in the European Union.

  18. Involvement of Calcium, Reactive Oxygen Species, and ATP in Hexavalent Chromium-Induced Damage in Red Blood Cells

    Directory of Open Access Journals (Sweden)

    Rong Zhang

    2014-11-01

    Full Text Available Aim: The aim of this study was to investigate the mechanisms of Cr6+-induced red blood cells (RBCs damage. Methods: The effect of Cr6+ exposure on RBCs was evaluated by hemolytic rate and blood gas assays. After exposure to 20 μM Cr6+, the percentage of phosphatidylserine (PS-exposing cells, intracellular Ca2+, reactive oxygen species (ROS, and ATP levels were evaluated, and cell morphology was observed. RBCs were exposed to Cr6+ in different Ringer solutions to investigate the role of changes of Ca2+, ROS, and ATP levels in eryptosis and morphology. Results: The Cr6+-induced damage of RBCs was dose-dependent. After a 6 h incubation with Cr6+, RBCs exhibited significant Ca2+ influx, ROS increase, ATP depletion, and PS exposure, but displayed no obvious change in morphology at this time point. After 24 h Cr6+ exposure, the RBCs decreased in size, appeared to be spike-like, and had decreased forward scatter. Inhibition of Ca2+ influx attenuated PS-exposure caused by 6 h Cr6+ exposure, but did not prevent 24 h Cr6+ exposure-induced morphological change in RBCs. Inhibition of rapid ATP consumption using adenine significantly ameliorated Cr6+-caused PS-exposure at 12 h, 24 h and 48 h, and prevented 24 h Cr6+ incubation-induced morphological change in RBCs. Conclusion: Cr6+ can lead to eryptosis. Ca2+ influx, increased ROS levels, and rapid ATP consumption are closely related to Cr6+-induced RBCs damage. Ca2+ influx plays an extremely important role in Cr6+-mediated toxicity.

  19. Oxygen uptake, heart rate and blood lactate concentration during a normal training session of an aerobic dance class.

    Science.gov (United States)

    De Angelis, M; Vinciguerra, G; Gasbarri, A; Pacitti, C

    1998-07-01

    The aim of this research was to investigate the physiological responses and, in particular, the participation of lactic acid anaerobic metabolism in aerobic dance, which is claimed to be pure aerobic exercise. In contrast to previous studies, that have put subjects in very unfamiliar situations, the parameters were monitored in the familiar context of gymnasium, practice routine and habitual instructor. A group of 30 skilled fairly well-trained women performed their usual routine, a combination of the two styles: low (LI) and high impact (HI), and were continuously monitored for heart rate (HR) and every 8 min for blood lactate concentration ([La-]b). Of the group, 15 were tested to determine their maximal aerobic power (VO2max) using a cycle-ergometer. They were also monitored during the routine for oxygen uptake (VO2) by a light telemetric apparatus. The oxygen pulses of the routine and of the corresponding exercise intensity in the incremental test were not statistically different. The mean values in the exercise session were: peak HR 92.8 (SD 7.8)% of the subject's maximal theoretical value, peak VO2 99.5 (SD 12.4)% of VO2max, maximal [La-]b 6.1 (SD 1.7) mmol x l(-1), and mean 4.8 (SD 1.3) mmol x l(-1). Repeated measures ANOVA found statistically significant differences between the increasing [La-]b values (P < 0.001). In particular, the difference between the [La-]b values at the end of the mainly LI phase and those of the LI-HI combination phase, and the difference between the samples during the combination LI-HI phase were both statistically significant (both P = 0.002 and P = 0.002). The similar oxygen pulses confirmed the validity of the present experiment design and the reliability of HR monitoring in this activity. The HR, VO2 and, above all, the increase of [La-]b to quite high values, showing a non steady state, demonstrated the high metabolic demand made by this activity that involved lactic acid metabolism at a much higher level than expected. PMID

  20. Oxygenation of saturated and unsaturated hydrocarbons with sodium periodate catalyzed by manganese(III) tetra-arylporphyrins, to study the axial ligation of imidazole

    Indian Academy of Sciences (India)

    Reza Tayebee

    2006-09-01

    Competitive oxygenation of cyclooctene and tetralin with sodium periodate catalyzed by MnIII(TPP)OAc, TPP = meso-tetraphenylporphyrin; MnIII (TNP)OAc, TNP = meso-tetrakis(1-naphthyl) porphyrin; MnIII (TMP)OAc, TMP = meso-tetrakis(2,4,6-trimethyl-phenyl)porphyrin; MnIII (TDCPP)OAc, TDCPP = meso-tetrakis(2,6-dichlorophenyl) porphyrin, and MnIII (TPNMe2-TFPP)OAc, TPNMe2-TFPP = meso-tetrakis(para-NMe2-tetrafluorophenyl)porphyrin, was carried out in the presence or absence of imidazole. This study showed that, in the absence of imidazole, selectivity for epoxide formation was high with electron-rich catalysts such as Mn(TPP)OAc, Mn(TNP)OAc and Mn(TMP)OAc, but low with electron-deficient catalysts such as Mn(TDCPP)OAc and Mn(TPNMe2-TFPP)OAc. Presumably, not only the axial ligation of imidazole to the four-coordinate Mn(III)-center, but also the steric and electronic influences of aryl-substituents on the porphyrin periphery affect the selectivity of the catalytic oxidation reaction.

  1. Effect of ultraviolet blood irradiation and oxygenation on nerve function and function of the red blood cell membrane pump in patients with acute cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    Jiaquan Wang; Chun Mao; Kaifu Ma; Shiqing Wang

    2006-01-01

    BACKGROUND: Ultraviolet blood irradiation and oxygenation (UBIO) has obtained better clinical effect in treating acute cerebral infarction, but the mechanism underlying this effect remains unclear.OBJECTIVE: To observe the effect of UBIO on the nerve function and activities of K+-Na+-ATPase and Ca2+-Mg2+-ATPase activities on the red blood cell (RBC) membrane of patients with acute cerebral infarction.DESIGN: A randomized and controlled study.SETTING: Department of Neurology, Xiangfan Central Hospital.PARTICIPANTS: From January 2000 to December 2001, excluding those above 70 years old, 58 cases of 700 patients with acute cerebral infarction admitted in the Department of Neurology, Xiangfan Central Hospital, were recruited and divided into two groups according to the random number table: UBIO treated group (n=28), including 17 males and 11 females, aged 40-68 years; and control group (n=30), including 20males and 10 females, aged 44-69 years. All the patients agreed to participate in the therapeutic program and detected items. The general informations were comparable without obvious differences between the two groups (P > 0.05).METHODS: ① The patients in both groups received routine treatments, besides, those in the UBIO treated group were given UBIO treatment by using the XL-200 type therapeutic apparatus produced in Shijiazhuang, whose ultraviolet wave was set at 253.7 nm with the energy density of 0.568 J/m2 per second, UBIO treatment started from the second day after admission, once every other day, with a single course consisting of 5-7 treatments. ② In the UBIO treated group, the venous blood was sampled before and after the first, third and the completion of the treatment course respectively, the venous blood was taken at each corresponding time point in the control group. After centrifugation of the blood at 10 000 rounds per minute,the RBC membrane was separated and then the activities of K+-Na+-ATPase and Ca2+-Mg2+-ATPase were detected by means of

  2. Multi-regional investigation of the relationship between functional MRI blood oxygenation level dependent (BOLD activation and GABA concentration.

    Directory of Open Access Journals (Sweden)

    Ashley D Harris

    Full Text Available Several recent studies have reported an inter-individual correlation between regional GABA concentration, as measured by MRS, and the amplitude of the functional blood oxygenation level dependent (BOLD response in the same region. In this study, we set out to investigate whether this coupling generalizes across cortex. In 18 healthy participants, we performed edited MRS measurements of GABA and BOLD-fMRI experiments using regionally related activation paradigms. Regions and tasks were the: occipital cortex with a visual grating stimulus; auditory cortex with a white noise stimulus; sensorimotor cortex with a finger-tapping task; frontal eye field with a saccade task; and dorsolateral prefrontal cortex with a working memory task. In contrast to the prior literature, no correlation between GABA concentration and BOLD activation was detected in any region. The origin of this discrepancy is not clear. Subtle differences in study design or insufficient power may cause differing results; these and other potential reasons for the discrepant results are discussed. This negative result, although it should be interpreted with caution, has a larger sample size than prior positive results, and suggests that the relationship between GABA and the BOLD response may be more complex than previously thought.

  3. Blood oxygenation level-dependent MRI of the skeletal muscle during ischemia in patients with peripheral arterial occlusive disease

    International Nuclear Information System (INIS)

    Purpose: to compare calf muscle Blood Oxygenation Level-Dependent (BOLD) response during ischemia in patients suffering from peripheral arterial occlusive disease (PAOD) and age-matched non-PAOD subjects. Materials and methods: PAOD patients with symptoms of intermittent calf claudication and an age-matched control group underwent T2*-weighted single-shot multi-echo planar imaging on a whole-body MR scanner at 1.5 T. The muscle BOLD signal in the calf was acquired during 60 sec of baseline and 240 sec of ischemia induced by cuff compression. T2* time courses in four calf muscles were evaluated. Results: significant differences in the mean T2* values were noted after 150 sec of measurement (p < 0.05). Patients with PAOD revealed a significantly reduced BOLD signal decrease compared to an age-matched control group. Conclusion: potential cause for this observation may be changes in the structure and/or the metabolic turnover of the muscle in PAOD patients. (orig.)

  4. Statistical mapping of effects of middle cerebral artery occlusion (MCAO) on blood flow and oxygen consumption in porcine brain.

    Science.gov (United States)

    Watanabe, Hideaki; Sakoh, Masaharu; Andersen, Flemming; Rodell, Anders; Sørensen, Jens Christian; Østergaard, Leif; Mouridsen, Kim; Cumming, Paul

    2007-02-15

    The volume of cerebral tissue perturbed in experimental models of middle cerebral artery occlusion (MCAO) can be highly variable. Thus, the territories of reduced cerebral blood flow (CBF) or oxygen consumption (CMRO(2)) following MCAO might properly be defined using statistical parametric mapping within a population. In order to establish such a method, we mapped CBF and CMRO(2) in 18 pigs with acute MCAO. Parametric maps were flipped about the axis of symmetry, and CBF and CMRO(2) in the infarcted hemisphere were calculated as percentages of the magnitudes in mirror-image pixels. There were log-linear relationships between the volumes of affected tissue and the percentages of normal CFB or CMRO(2). This graphical analysis showed that the volume of the core deficit was smaller for CBF that for CMRO(2), but expanded more rapidly with decreasing CBF deficit than did the corresponding volumes of reduced CMRO(2). Thus, acute changes in CBF and CMRO(2) following MCAO in the pig can be defined as probabilistic volumes. PMID:17129609

  5. Blood oxygenation level-dependent MRI of the skeletal muscle during ischemia in patients with peripheral arterial occlusive disease

    Energy Technology Data Exchange (ETDEWEB)

    Potthast, Silke [Unispital Basel, Inst. fuer Radiologie (Switzerland); Schulte, A. [Univ. Hospital Ulm (Germany). Clinic for Radiation Therapy and Radiooncology; Kos, S.; Bilecen, D. [Unispital Basel, Interventional Radiology (Switzerland); Aschwanden, M. [Unispital Basel (Switzerland). Angiologie

    2009-12-15

    Purpose: to compare calf muscle Blood Oxygenation Level-Dependent (BOLD) response during ischemia in patients suffering from peripheral arterial occlusive disease (PAOD) and age-matched non-PAOD subjects. Materials and methods: PAOD patients with symptoms of intermittent calf claudication and an age-matched control group underwent T2*-weighted single-shot multi-echo planar imaging on a whole-body MR scanner at 1.5 T. The muscle BOLD signal in the calf was acquired during 60 sec of baseline and 240 sec of ischemia induced by cuff compression. T2* time courses in four calf muscles were evaluated. Results: significant differences in the mean T2* values were noted after 150 sec of measurement (p < 0.05). Patients with PAOD revealed a significantly reduced BOLD signal decrease compared to an age-matched control group. Conclusion: potential cause for this observation may be changes in the structure and/or the metabolic turnover of the muscle in PAOD patients. (orig.)

  6. A microfluidic system enabling Raman measurements of the oxygenation cycle in single optically trapped red blood cells.

    Science.gov (United States)

    Ramser, Kerstin; Enger, Jonas; Goksör, Mattias; Hanstorp, Dag; Logg, Katarina; Käll, Mikael

    2005-04-01

    Using a lab-on-a-chip approach we demonstrate the possibility of selecting a single cell with certain properties and following its dynamics after an environmental stimulation in real time using Raman spectroscopy. This is accomplished by combining a micro Raman set-up with optical tweezers and a microfluidic system. The latter gives full control over the media surrounding the cell, and it consists of a pattern of channels and reservoirs defined by electron beam lithography that is moulded into rubber silicon (PDMS). Different buffers can be transported through the channels using electro-osmotic flow, while the resonance Raman response of an optically trapped red blood cell (RBC) is simultaneously registered. This makes it possible to monitor the oxygenation cycle of the cell in real time and to investigate effects like photo-induced chemistry caused by the illumination. The experimental set-up has high potential for in vivo monitoring of cellular drug response using a variety of spectroscopic probes. PMID:15791341

  7. Resonance Raman study of the oxygenation cycle of optically trapped single red blood cells in a microfluidic system

    Science.gov (United States)

    Ramser, Kerstin; Logg, Katarina; Enger, Jonas; Goksor, Mattias; Kall, Mikael; Hanstorp, Dag

    2004-10-01

    The average environmental response of red blood cells (RBCs) is routinely measured in ensemble studies, but in such investigations valuable information on the single cell level is obscured. In order to elucidate this hidden information is is important to enable the selection of single cells with certain properties while subsequent dynamics triggered by environmental stimulation are recorded in real time. It is also desirable to manipulate and control the cells under phsyiological conditions. As shown here, this can be achieved by combining optical tweezers with a confocal Raman set-up equipped with a microfluidic system. A micro-Raman set-up is combined with an optical trap with separate optical paths, lasers and objectives, which enables the acquisition of resonance Raman profils of single RBCs. The microfluidic system, giving full control over the media surrounding the cell, consists of a pattern of channels and reservoirs produced by electron beam lithography and moulded in PDMS. Fresh Hepes buffer or buffer containing sodium dithionite are transported through the channels using electro-osmotic flow, while the direct Raman response of the single optically trapped RBC is registered in another reservoir in the middle of the channel. Thus, it is possible to monitor the oxygenation cycle in a single cell and to study photo-induced chemistry. This experimental set-up has high potential for monitoring the drug response or conformational changes caused by other environmental stimuli for many types of single functional cells since "in vivo" conditions can be created.

  8. Preoperative 3T high field blood oxygen level dependent functional magnetic resonance imaging for glioma involving sensory cortical areas

    Institute of Scientific and Technical Information of China (English)

    LI Shao-wu; WANG Jiang-fei; JIANG Tao; LI Shou-wei; ZHANG Wen-bo; LI Zi-xiao; ZHANG Zhong; DAI Jian-ping; WANG Zhong-cheng

    2010-01-01

    Background Localization of sensory cortical areas during the operation is essential to preserve the sensory function.Intraoperative direct electrostimulation under awake anesthesia is the golden standard but time-consuming. We applied 3T high field blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to identify the relationship between glioma and cortical sensory areas preoperatively and to guide intraoperative direct electrostimulation for quick and precise localization.Methods Five glioma patients with sensory cortex involvement by or next to the lesion had preoperative BOLD fMRI to determine the spatial relationship of cortical sensory areas to the tumours. Bilateral hand opposite movement was performed by these patients for fMRI. Precentral and postcentral gyri were identified by electrical stimulation during the operation. Karnofsky Performance Status scores of the patients' pre- and postoperative and the role of BOLD fMRI were evaluated.Results The cortical sensory areas were all activated in five glioma patients involving postcentral gyrus areas by BOLDf MRI with bilateral hand opposite movement. The detected activation areas corresponded with the results from cortical electrical stimulation.Conclusions The relationship between cortical sensory areas and tumour can be accurately shown by BOLD fMRI before operation. And the information used to make the tumour resection could obtain good clinical results.

  9. Measurement of brain oxygenation changes using dynamic T1-weighted imaging

    DEFF Research Database (Denmark)

    Haddock, Bryan; Larsson, Henrik B W; Hansen, Adam E;

    2013-01-01

    Magnetic resonance imaging (MRI) has proven useful in evaluating oxygenation in several types of tissue and blood. This study evaluates brain tissue oxygenation changes between normoxia and hyperoxia in healthy subjects using dynamic T1 and T2*-weighted imaging sequences. The change in FiO2 induced...... by hyperoxia caused a significant decrease in T1. A model to determine changes in tissue oxygen tension from the T1-weighted MRI signal is presented based on previous findings that T1 is sensitive to oxygen tension whereas T2* is sensitive to blood saturation. The two sequences produce results with...

  10. Accuracy and Precision of MR Blood Oximetry Based On the Long Paramagnetic Cylinder Approximation of Large Vessels

    OpenAIRE

    Langham, Michael C; Magland, Jeremy F; Epstein, Charles L.; Floyd, Thomas F; Wehrli, Felix W.

    2009-01-01

    An accurate non-invasive method to measure hemoglobin oxygen saturation (%HbO2) of deep-lying vessels without catheterization would have many clinical applications. Quantitative MRI may be the only imaging modality that can address this difficult and important problem. MR susceptometry-based oximetry for measuring blood oxygen saturation in large vessels models the vessel as a long paramagnetic cylinder immersed in an external field. The intravascular magnetic susceptibility relative to surro...

  11. Oxygenation to Bovine Blood in Artificial Heart and Lung Using Vibrating Flow Pump: Experiment and Numerical Analysis Based on Non-Newtonian Model

    Science.gov (United States)

    Shintaku, Hirofumi; Yonemura, Tsubasa; Tsuru, Kazuaki; Isoyama, Takashi; Yambe, Tomoyuki; Kawano, Satoyuki

    In this study, we construct an experimental apparatus for a prototype artificial heart and lung (AHL) by installing hollow fibers into the cylindrical tube of the vibrating flow pump (VFP). The oxygenation characteristics are investigated both by experiments using bovine blood and by numerical analyses based on the computational fluid dynamics. The analyses are carried out at the Reynolds numbers Re ranged from O(1) to O(103), which are determined based on the experimental conditions. The blood flow and the diffusion of oxygen gas are analyzed based on the Newtonian/non-Newtonian, unsteady, incompressible and axisymmetric Navier-Stokes equations, and the advection-diffusion equation. The results show that the oxygenation rate increases in proportion to Re1/3, where the phenomenon corresponds to the decreasing thickness of the concentration boundary layer with Re. Although the effects of the vibrating flow and the rheology of the blood are clearly appeared on the velocity field, their effects on the gas exchange are relatively small at the ranges of prescribed Reynolds numbers. Furthermore, the numerical results in terms of the oxygenation rate are compared with the experimental ones. The basic design data of VFP were accumulated for the development of AHL in the clinical applications.

  12. Circulation time determined by carotid angiography in patients with chronic internal Carotid artery occlusion. Comparison with cerebral blood flow and oxygen metabolism measured by PET

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroshi; Inugami, Atsushi (Research Inst. for Brain and Blood Vessels, Akita (Japan)); Shishido, Fumio (and others)

    1994-10-01

    The degree of collateral circulation in patients with unilaterally chronic internal carotid artery occlusion was estimated by mean transit time of contrast material in rapid sequence carotid angiography (Angiographic MTT), and compared with cerebral blood flow and oxygen metabolism measured by PET. In normal density region on X-ray CT, a significant negative correlation was observed between Angiographic MTT and cerebral blood flow (CBF). This indicates that cerebral blood flow can be estimated by Angiographic MTT. It has been reported that the ratio of cerebral blood volume (CBV) to CBF (CBV/CBF), i.e., mean transit time determined by PET well agreed with OEF, and is good indicator for brain circulation reserve. In this study, no significant correlation was observed between Angiographic MTT and CBV/CBF. However, a significant positive correlation was observed between Angiographic MTT and oxygen extraction fraction (OEF), and no significant correlation was observed between Angiographic MTT and oxygen consumption rate (CMRO[sub 2]). These indicates that Angiographic MTT may be indicator for brain circulation reserve. (author).

  13. 睡眠呼吸紊乱对慢性阻塞性肺疾病夜间血氧的影响%Effects of sleep disordered breathing in patients with chronic obstructive pulmonary disease nocturnal oxygen saturation

    Institute of Scientific and Technical Information of China (English)

    于苓; 王慧玲; 谢广宏

    2013-01-01

    Objective To investigate the effects of nocturnal sleep breathing disturbance on arterial oxygen saturation in chronic obstructive pulmonary disease (COPD) patients with wakingoxygen saturation of >90%. Sixty-six patients were divided into stable COPD group (n=22), acute embittering chronic obstructive pulmonary disease (AECOPD) group (n=20), overlap syndrome group (n=24) and control group (n=10). COPD patients with waking SaO2>90%are apt to show nocturnal hypoxemia. The disease situation is associated with the hyoxemia in patients with COPD.%观察清醒状态血氧饱和度大于90%的COPD患者夜间睡眠呼吸紊乱对动脉血氧的影响,为临床重视和治疗COPD夜间低氧血症、防止并发症提供依据。选择COPD患者66例,包括AECOPD 20例、COPD稳定期22例、重叠综合征组24例,设正常对照组10例。提示COPD患者夜间睡眠时存在低通气状态,以合并阻塞型睡眠呼吸暂停综合症最为严重,可使清醒状态下血氧饱和度大于90%的COPD患者夜间睡眠发生低氧血症,COPD病情严重程度与动脉血氧下降存在一定联系。

  14. The preliminary study of Ultraviolet-Irradiated and Oxygenated Blood Transfusion Therapy(UOBT) for Experimental Cerebral Infarction of Animal Brain Model

    Institute of Scientific and Technical Information of China (English)

    Su Xiu-Chu; Feng You-Qi; Zhou gang; Wu jun-yi

    2000-01-01

    In this presented study, we have developed a photochemical model of cerebral in farction in rabbit with stable and reproducible infarct size and extent. This model is similar to the pathological changes in human cerebral infarction. Using this model, therapeutic effects and mechanisms of UOBT on brain ischemic injury were invetigated in rabbits following the photochemical infarcnon The results showed that UOBT could significantly reduce the mtarcted size, and improve the cerebral blood flow compared with the control animals treated with non-u-radiated ad non-oxygenated blood transfusion. These data suggest that the UOBT may have a therapeutic potential for clinical rehabilitation effect in stroke treatment

  15. Correlation between quantitative EEG and cerebral blood flow and oxygen metabolism in patients with dementia of Alzheimer type

    International Nuclear Information System (INIS)

    Quantitative scalp EEG and cerebral blood flow (CBF) and oxygen metabolism (CMRO2) measured by the steady-state 15O technique and positron emission tomography were studied in 19 patients with mild to moderate dementia of Alzheimer type (DAT) and age-matched controls (EEG=19, PET=6). Scalp electrodes were placed according to the international 10-20 method except for Cz, T3, and T4. To evaluate the relative changes in power for each frequency band between the two groups, the percentage power fraction (percentage power for each frequency band at a site compared to the total power at that site; %delta for 2.0-3.8 Hz, %theta for 4.0-7.8 Hz, %alpha for 8.0-12.8 Hz, %beta for 13.0-25.4 Hz) was calculated. Compared with controls, DAT patients showed a significant decrease in %alpha, while significant increases in %theta at all electrodes, and significant increases in %delta at the temporal, parietal and occipital electrodes were observed. The patient group displayed a significant decrease in rCBF and rCMRO2 in the parietal, temporal and frontal cortices, but the reduction in rCMRO2 was less remarkable than that of rCBF. %Theta at P3, O1 and O2 showed a significant negative correlation with rCBF, and %theta at P3, O1showed a significant negative correlation with rCMRO2. %Delta at P3, P4 and T5 was significantly negatively correlated with rCBF in the corresponding regions, and %alpha at almost all the electrodes (except O1, F3, P3) was significantly positively correlated with rCBF in the corresponding regions. %Delta and %alpha did not show any significant correlation with rCMRO2. (author)

  16. Preoperative blood oxygen level-dependent functional magnetic resonance imaging in patients with gliomas involving the motor cortical areas

    Institute of Scientific and Technical Information of China (English)

    XIE Jian; CHEN Xu-zhu; JIANG Tao; LI Shou-wei; LI Zi-xiao; ZHANG Zhong; DAI Jian-ping; WANG Zhong-cheng

    2008-01-01

    Background Blood oxygen level-dependent(BOLD)functional magnetic resonance imaging(fMRI)plays an important role in identifying functional cortical areas of the brain.especially In patients with gliomas.This study aimed to assess the value of fMRI in presurgical planning and functional outcome of patients with gliomas in the motor cortical areas.Methods Twenty-six patients with gliomas in the motor cortex were recruited in the study.Before operation.fMRI was performed in each patient to obtain the mapping of bilateral hands area on the primary sensorimotor cortex.This examination was performed on a 3.0T scanner with a bilateral hands movement paradigm.During microsurgery under awake anesthesia,the motor area was identified using direct electrical stimulation and compared with preoperative mapping.Finally the tumor was resected as much as possible with the motor cortex preserved in each patlent.Karnofsky performance status(KPS)was evaluated in all patients before and after operation.Results Twenty-three patients showed a successful fMRI mapping.Among them,19 were calssified to be grade Ⅲ;4,grade Ⅱ;3,grade Ⅰ.The operation time was about 7 hours in the 23 patients,8.5 hours in the other 3.The pre- and pOstODerative KPS score was 82.3±8.6 and 94.2±8.1,respectively.Conclusions Preoperative fMRI of the hand motor area shows a high consistency with intraoperative cortical electronic stimulation.Combined use of the two methods shows a maximum benefit in surgical treatment.

  17. The effects of anticholinergic drugs on regional cerebral blood flow, and oxygen metabolism in previously untreated patients with Parkinson's disease

    International Nuclear Information System (INIS)

    Regional cerebral blood flow (rCBF) and oxygen metabolism (rCMRO2) were measured using the steady-state 15O technique and positron emission tomography (PET) in six previously untreated patients with Parkinson's disease before and after trihexyphenidyl (THP) treatment. The patients comprised of 4 men and 2 women with Hoehn-Yahr stage II-III. Their ages at the onset of the study ranged from 46 to 57 years (mean±SD, 51.8±3.7) and the duration of the illness ranged from 10 to 48 months (mean±SD, 28.8±15.5). The PET study, assessments of the disability and cognitive function were undergone twice. The first time assessments were done was when the patients were not receiving any drugs, and the second time was one to three months after administration of 6 mg THP. All patients showed clinical improvement after THP treatment. The mean disability score of Unified Parkinson's Disease Rating Scale decreased from 35.1 (SD±11.3) to 25.7 (SD±11.6). The cognitive function assessed by Hasegawa's dementia rating scale-revised, Mini-Mental State Examination, Wechsler Adult Intelligence Scale-Revised, and Wechsler Memory Scale-Revised, were not significantly different before and after the THP treatment. After the THP treatment, rCBF and rCMRO2 decreased significantly in the striatum (about 15%) and all cerebral cortices (about 10%) on both sides contralateral and ipsilateral to the predominantly symptomatic limbs. We conclude that an anticholinergic THP decreases the rCBF and rCMRO2 significantly in the cerebral cortices without cognitive impairment in early untreated patients with Parkinson's disease. (author)

  18. Visible light optical coherence tomography measure retinal oxygen metabolic response to systemic oxygenation (Conference Presentation)

    Science.gov (United States)

    Yi, Ji; Liu, Wenzhong; Chen, Siyu; Backman, Vadim; Sheibani, Nader; Sorenson, Christine M.; Fawzi, Amani A.; Linsenmeier, Robert A.; Zhang, Hao F.

    2016-03-01

    The lack of capability to quantify oxygen metabolism noninvasively impedes both fundamental investigation and clinical diagnosis of a wide spectrum of diseases including all the major blinding diseases such as age-related macular degeneration, diabetic retinopathy, and glaucoma. Using visible light optical coherence tomography (vis-OCT), we demonstrated accurate and robust measurement of retinal oxygen metabolic rate (rMRO2) noninvasively in rat eyes. The rMRO2 was calculated by concurrent measurement of blood flow and blood oxygen saturation (sO2). Blood flow was calculated by the principle of Doppler optical coherence tomography, where the phase shift between two closely spaced A-lines measures the axial velocity. The distinct optical absorption spectra of oxy- and deoxy-hemoglobin provided the contrast for sO2 measurement, combined with the spectroscopic analysis of vis-OCT signal within the blood vessels. We continuously monitored the regulatory response of oxygen consumption to a progressive hypoxic challenge. We found that both oxygen delivery, and rMRO2 increased from the highly regulated retinal circulation (RC) under hypoxia, by 0.28+/-0.08 μL/min (p<0.001), and 0.20+/-0.04 μL/min (p<0.001) per 100 mmHg systemic pO2 reduction, respectively. The increased oxygen extraction compensated for the deficient oxygen supply from the poorly regulated choroidal circulation (CC).

  19. Whole blood-oxygen binding properties of four cold-temperate marine fishes: blood affinity is independent of pH-dependent binding, routine swimming performance, and environmental hypoxia

    DEFF Research Database (Denmark)

    Herbert, Neill A; Skov, Peter V; Wells, Rufus M G;

    2006-01-01

    The relationship between whole blood-oxygen affinity (P(50)) and pH-dependent binding (i.e., cooperativity and the Bohr [ Phi ] and Root effects) was examined statistically under standardized conditions (10.0 degrees Celsius) in four unrelated cold-temperate marine fishes that differ widely in...... swimming performance and the predicted low O(2) response of each species. The ecotype of the four marine species was also unrelated to pH-dependent binding because no difference in the Bohr effect was apparent ( Phi varied insignificantly from -0.90 to -1.06), and differences in the magnitude of the...... their swimming performance and their expected responses to hypoxia: cod (Gadus morhua), herring (Clupea harengus), mackerel (Scomber scombrus), and plaice (Pleuronectes platessa). An unexpected difference in blood-oxygen affinity was found (herring>plaice>mackerel>cod), and this was independent of both...

  20. A genome-wide association study of saturated, mono- and polyunsaturated red blood cell fatty acids in the Framingham Heart Offspring Study.

    Science.gov (United States)

    Tintle, N L; Pottala, J V; Lacey, S; Ramachandran, V; Westra, J; Rogers, A; Clark, J; Olthoff, B; Larson, M; Harris, W; Shearer, G C

    2015-03-01

    Most genome-wide association studies have explored relationships between genetic variants and plasma phospholipid fatty acid proportions, but few have examined apparent genetic influences on the membrane fatty acid profile of red blood cells (RBC). Using RBC fatty acid data from the Framingham Offspring Study, we analyzed over 2.5 million single nucleotide polymorphisms (SNPs) for association with 14 RBC fatty acids identifying 191 different SNPs associated with at least 1 fatty acid. Significant associations (pFADS (chromosome 11) and ELOVL (chromosome 6) regions. Multiple SNPs explained 8-14% of the variation in 3 high abundance (>11%) fatty acids, but only 1-3% in 4 low abundance (genes influence tissue fatty acid content and pathways modulated by fatty acids. PMID:25500335

  1. Combination of blood oxygen level–dependent functional magnetic resonance imaging and visual evoked potential recordings for abnormal visual cortex in two types of amblyopia

    OpenAIRE

    Wang, Xinmei; Cui, Dongmei; Zheng, Ling; Yang, Xiao; Yang, Hui; Zeng, Junwen

    2012-01-01

    Purpose To elucidate the different neuromechanisms of subjects with strabismic and anisometropic amblyopia compared with normal vision subjects using blood oxygen level–dependent functional magnetic resonance imaging (BOLD-fMRI) and pattern-reversal visual evoked potential (PR-VEP). Methods Fifty-three subjects, age range seven to 12 years, diagnosed with strabismic amblyopia (17 cases), anisometropic amblyopia (20 cases), and normal vision (16 cases), were examined using the BOLD-fMRI and PR...

  2. Influence of skin blood flow and source-detector distance on near-infrared spectroscopy-determined cerebral oxygenation in humans

    DEFF Research Database (Denmark)

    Hirasawa, Ai; Yanagisawa, Shintaro; Tanaka, Naoki;

    2015-01-01

    semi-recumbent position, while extracranial blood flow was restricted by application of four different pressures (+20 to +80 mmHg) to the left temporal artery. The O2 Hb was measured at the forehead via a multidistance probe (source-detector distance; 15, 22·5 and 30 mm), and SkBF was determined by...... to 30 mm. Therefore, new algorithms need to be developed for unbiased NIRS detection of cerebral oxygenation....

  3. The effects of altitude/hypoxic training on oxygen delivery capacity of the blood and aerobic exercise capacity in elite athletes – a meta-analysis

    Science.gov (United States)

    Park, Hun-young; Hwang, Hyejung; Park, Jonghoon; Lee, Seongno; Lim, Kiwon

    2016-01-01

    [Purpose] This study was designed as a meta-analysis of randomized controlled trials comparing effectiveness of altitude/hypoxic training (experimental) versus sea-level training (control) on oxygen delivery capacity of the blood and aerobic exercise capacity of elite athletes in Korea. [Methods] Databases (Research Information Service System, Korean studies Information Service System, National Assembly Library) were for randomized controlled trials comparing altitude/hypoxic training versus sea-level training in elite athletes. Studies published in Korea up to December 2015 were eligible for inclusion. Oxygen delivery capacity of the blood was quantified by red blood cell (RBC), hemoglobin (Hb), hematocrit (Hct), erythropoietin (EPO); and aerobic exercise capacity was quantified by maximal oxygen consumption (VO2max). RBC, Hb, Hct, VO2max represented heterogeneity and compared post-intervention between altitude/hypoxic training and sea-level training in elite athletes by a random effect model meta-analysis. EPO represented homogeneity and meta-analysis performed by a fixed effect model. Eight independent studies with 156 elite athletes (experimental: n = 82, control: n = 74) were included in the metaanalysis. [Results] RBC (4.499×105 cell/ul, 95 % CI: 2.469 to 6.529), Hb (5.447 g/dl, 95 % CI: 3.028 to 7.866), Hct (3.639 %, 95 % CI: 1.687 to 5.591), EPO (0.711 mU/mL, 95% CI: 0.282 to 1.140), VO2max (1.637 ml/kg/min, 95% CI: 0.599 to 1.400) showed significantly greater increase following altitude/hypoxic training, as compared with sea-level training. [Conclusion] For elite athletes in Korea, altitude/ hypoxic training appears more effective than sea-level training for improvement of oxygen delivery capacity of the blood and aerobic exercise capacity. PMID:27298808

  4. Effects of the Oxygen-Carrying Solution OxyVita C on the Cerebral Microcirculation and Systemic Blood Pressures in Healthy Rats

    Directory of Open Access Journals (Sweden)

    Rania Abutarboush

    2014-11-01

    Full Text Available The use of hemoglobin-based oxygen carriers (HBOC as oxygen delivering therapies during hypoxic states has been hindered by vasoconstrictive side effects caused by depletion of nitric oxide (NO. OxyVita C is a promising oxygen-carrying solution that consists of a zero-linked hemoglobin polymer with a high molecular weight (~17 MDa. The large molecular weight is believed to prevent extravasation and limit NO scavenging and vasoconstriction. The aim of this study was to assess vasoactive effects of OxyVita C on systemic blood pressures and cerebral pial arteriole diameters. Anesthetized healthy rats received four intravenous (IV infusions of an increasing dose of OxyVita C (2, 25, 50, 100 mg/kg and hemodynamic parameters and pial arteriolar diameters were measured pre- and post-infusion. Normal saline was used as a volume-matched control. Systemic blood pressures increased (P ≤ 0.05 with increasing doses of OxyVita C, but not with saline. There was no vasoconstriction in small (<50 µm and medium-sized (50–100 µm pial arterioles in the OxyVita C group. In contrast, small and medium-sized pial arterioles vasoconstricted in the control group. Compared to saline, OxyVita C showed no cerebral vasoconstriction after any of the four doses evaluated in this rat model despite increases in blood pressure.

  5. Effects of oxygenation and the stress hormones adrenaline and cortisol on the viscosity of blood from the trout oncorhynchus mykiss

    DEFF Research Database (Denmark)

    Sørensen, Bodil; Weber, Roy

    1995-01-01

    Although the concentrations of the stress hormones adrenaline and cortisol in rainbow trout (Oncorhynchus mykiss) blood increase upon hypoxic exposure, the combined effects of these hormones and O2 lack upon fish blood rheology have not been investigated. Deoxygenated blood taken by caudal puncture...

  6. Measuring tissue oxygenation

    Science.gov (United States)

    Soyemi, Olusola O. (Inventor); Soller, Babs R. (Inventor); Yang, Ye (Inventor)

    2009-01-01

    Methods and systems for calculating tissue oxygenation, e.g., oxygen saturation, in a target tissue are disclosed. In some embodiments, the methods include: (a) directing incident radiation to a target tissue and determining reflectance spectra of the target tissue by measuring intensities of reflected radiation from the target tissue at a plurality of radiation wavelengths; (b) correcting the measured intensities of the reflectance spectra to reduce contributions thereto from skin and fat layers through which the incident radiation propagates; (c) determining oxygen saturation in the target tissue based on the corrected reflectance spectra; and (d) outputting the determined value of oxygen saturation.

  7. Clinical usefulness of positron emission tomography in the evaluation of regional cerebral blood flow and cerebral oxygen metabolism under glycerol and carbon dioxide loadings

    Energy Technology Data Exchange (ETDEWEB)

    Tanada, Shuji; Yonekura, Yoshiharu; Senda, Michio

    1987-02-01

    Cerebral blood flow (CBF) and oxygen metabolism (CMRO/sub 2/) were studied in normal cerebral cortices by positron emission tomography using continuous inhalation method of oxygen-15 labeled carbon dioxide and oxygen, and single inhalation method of oxygen-15 labeled carbon monoxide. The values of CBF, CMRO/sub 2/, and oxygen extraction fraction (OEF) in cerebral cortices of 18 healthy normal volunteers represented 40 +- 7 ml/100 ml/min, 3.2 +- 0.5 ml O/sub 2//100 ml/min, and 0.43 +- 0.07, respectively. In cases with glycerol loading, CBF increased in 10/14 cases. Studies of 6 cases with intracranial pressure indicated the presence of mechanism by which depressed CMRO/sub 2/ improved and was kept in normal values. The loading of 5% carbon dioxide showed an increase in CBF in cases with cerebral infarction, which implied the good cerebral vascular response to the elevated arterial carbon dioxide, but no particular changes were observed in CMRO/sub 2/ which seemed to be less responsive to the elevated arterial carbon dioxide level. In cases with moyamoya disease, 5% carbon dioxide loading showed no changes in CBF and CMRO/sub 2/. This suggested the poor cerebral vascular response to the elevation of arterial carbon dioxide, while X-ray CT failed to demonstrate any abnormalities in corresponding areas. Positron emission tomography proved to have a great potentiality regarding the evaluation of the changes in cerebral blood flow and cerebral oxygen metabolism under various loadings.

  8. The role of tissue oxygen tension in the control of local blood flow in the microcirculation of skeletal muscles

    DEFF Research Database (Denmark)

    Ngo, Thuc Anh

    2010-01-01

    . In a separate study we examined if low or high oxygen caused any change in the intracellular Ca2+ concentration of isolated mouse cremaster arterioles using fluorescent microscopy. Cremaster arterioles were isolated by gentle microdissection, loaded with Fura-PE3 (calcium fluorescent dye) and placed...... high oxygen perfusate. Possible explanations for these findings could be: a) that the oxygen sensing mechanism was damaged during the dissection procedure, b) changes in oxygen tension does not cause changes in the intracellular Ca2+ concentration, but rather changes the Ca2+ sensitivity of contractive...

  9. Angioplasty and stenting for severe vertebral artery oriifce stenosis:effects on cerebellar function remodeling veriifed by blood oxygen level-dependent functional magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    Bo Liu; Zhiwei Li; Peng Xie

    2014-01-01

    Vertebral artery oriifce stenting may improve blood supply of the posterior circulation of the brain to regions such as the cerebellum and brainstem. However, previous studies have mainly focused on recovery of cerebral blood lfow and perfusion in the posterior circulation after inter-ventional therapy. This study examined the effects of functional recovery of local brain tissue on cerebellar function remodeling using blood oxygen level-dependent functional magnetic reso-nance imaging before and after interventional therapy. A total of 40 Chinese patients with severe unilateral vertebral artery oriifce stenosis were enrolled in this study. Patients were equally and randomly assigned to intervention and control groups. The control group received drug treat-ment only. The intervention group received vertebral artery oriifce angioplasty and stenting+identical drug treatment to the control group. At 13 days after treatment, the Dizziness Handicap Inventory score was compared between the intervention and control groups. Cerebellar function remodeling was observed between the two groups using blood oxygen level-dependent function-al magnetic resonance imaging. The improvement in dizziness handicap and cerebellar function was more obvious in the intervention group than in the control group. Interventional therapy for severe vertebral artery oriifce stenosis may effectively promote cerebellar function remodeling and exert neuroprotective effects.

  10. A new hemodynamic model shows that temporal perturbations of cerebral blood flow and metabolic rate of oxygen cannot be measured individually using functional near-infrared spectroscopy

    International Nuclear Information System (INIS)

    A recent dynamic model relates the functional near-infrared spectroscopy (fNIRS) measurements to hemodynamic and metabolic parameters. This note reports modified expressions of the new model in terms of cerebral blood volume (CBV), blood flow (CBF) and metabolic rate of oxygen (CMRO2). On the basis of these modified expressions, the new model reproduces known steady state relationships between hemoglobin concentration, CBF and CMRO2, and yields time-dependent relationships that describe transient changes. This new model allows for the translation of the fNIRS measurements into dynamic measures of ΔCBV/CBV0 and the difference ΔCBF/CBF0 – ΔCMRO2/CMRO2|0, provided that some baseline physiological parameters and a relationship between overall, arterial and venous blood volume changes are assumed. (note)

  11. Preservation of canine myocardial high-energy phosphates during low-flow ischemia with modification of hemoglobin–oxygen affinity

    OpenAIRE

    Weiss, Robert G.; Mejia, Marco A.; Kass, David A.; DiPaula, Anthony F.; Becker, Lewis C; Gerstenblith, Gary; Chacko, V P

    1999-01-01

    Conventional approaches for the treatment of myocardial ischemia increase coronary blood flow or reduce myocardial demand. To determine whether a rightward shift in the hemoglobin–oxygen saturation curve would reduce the metabolic and contractile effects of a myocardial oxygen-supply imbalance, we studied the impact of a potent synthetic allosteric modifier of hemoglobin–oxygen affinity, a 2-[4-[[(3,5-disubstituted anilino)carbonyl]methyl] phenoxy] -2-methylproprionic acid derivative (RSR13),...

  12. Quantification of tumour vasculature and hypoxia by immunohistochemical staining and HbO2 saturation measurements.

    Science.gov (United States)

    Fenton, B M; Paoni, S F; Lee, J; Koch, C J; Lord, E M

    1999-02-01

    Despite the possibility that tumour hypoxia may limit radiotherapeutic response, the underlying mechanisms remain poorly understood. A new methodology has been developed in which information from several sophisticated techniques is combined and analysed at a microregional level. First, tumour oxygen availability is spatially defined by measuring intravascular blood oxygen saturations (HbO2) cryospectrophotometrically in frozen tumour blocks. Second, hypoxic development is quantified in adjacent sections using immunohistochemical detection of a fluorescently conjugated monoclonal antibody (ELK3-51) to a nitroheterocyclic hypoxia marker (EF5), thereby providing information relating to both the oxygen consumption rates and the effective oxygen diffusion distances. Third, a combination of fluorescent (Hoechst 33342 or DiOC7(3)) and immunohistological (PECAM-1/CD31) stains is used to define the anatomical vascular densities and the fraction of blood vessels containing flow. Using a computer-interfaced microscope stage, image analysis software and a 3-CCD colour video camera, multiple images are digitized, combined to form a photo-montage and revisited after each of the three staining protocols. By applying image registration techniques, the spatial distribution of HbO2 saturations is matched to corresponding hypoxic marker intensities in adjacent sections. This permits vascular configuration to be related to oxygen availability and allows the hypoxic marker intensities to be quantitated in situ. PMID:10027314

  13. Blood oxygenation level dependent functional MRI study on the changes of motor cortex in patients with amyotrophic lateral sclerosis

    International Nuclear Information System (INIS)

    Objective: To study the changes of motor cortex in patients with amyotrophic lateral sclerosis (ALS) while executing sequential finger tapping movement by using blood oxygenation level dependent (BOLD) functional MRI. Methods: Fifteen patients with definite or probable ALS and 15 age and gender matched normal controls were enrolled in the BOLD study, and all the subjects were right-handed with no other diseases or any recent medication history. A 3.0 T MR scanner' was employed and gradient echo EPI (GRE-EPI)sequence was used to acquire the functional images. Subjects executed sequential finger tapping movement at a frequency of 1-2 Hz during a block design task. fMRI data were analyzed by using statistical parametric mapping (SPM) 2. Volume of activated brain areas was compared with the use of a Student's t-test. Results: Bilateral primary sensorimotor cortex (PSM), bilateral posterior aspect of premotor area (PA), bilateral supplementary motor area (SMA), contralateral inferior lateral premotor area (ILPA), bilateral parietal region (PAR), and ipsilateral cerebellum showed activation in both ALS patients and normal controls when executing the same motor task. The activation areas in bilateral PSM and bilateral posterior aspect of PA ( right hand ipsilateral activation: ALS (924.5±141.1) mm3, control (829.9± 98.4) mm3, P=0.05; right hand contralateral activation: ALS (9143.8±702.8) mm3, control (8638.8±506.4) mm3 P3, control (902.5±3 184.2)mm, P3, control (5934.6±616.4) mm3, P3, control (4710.7±416.3) mm3, P3, control (3688.9±672.3) mm3, P3, control (254.3±84.4) mm3, P3, control (1689.0±719.6) mm3, P<0.05) were significantly larger in ALS patients than in normal controls. Extra activation areas including ipsilateral ILPA, contralateral cerebellum and bilateral posterior limb of internal capsule were only detected in ALS patients. Conclusions: Similar activation areas were seen in both groups while executing the same motor task, but the activated areas

  14. THE INFLUENCE OF HYPERBARIC OXYGEN THERAPY ENVIRONMENT ON BLOOD PRESSURE AND PULSE OF PERSONNEL IN OXYGEN-CABIN%高压氧治疗环境对舱内人员血压和脉搏的影响

    Institute of Scientific and Technical Information of China (English)

    李红玲; 薛新萍; 牛蕾蕾; 张会萍

    2013-01-01

    目的 探讨高压氧治疗环境对舱内人员血压和脉搏的影响.方法 随机选择高压氧治疗组(患者)136例,高气压环境组(健康正常的陪舱人员)30例,使用欧姆龙智能电子血压计分别在进舱前、加压吸氧(1.8ATA)、稳压吸氧(2.2ATA)、稳压休息(2.2ATA)、吸氧结束(减压前2.2ATA)、减压结束出舱后测量进舱人员的血压和脉搏.测量体位一般取坐位(9例患者取卧位),全部测量右侧上肢肱动脉.测量时间均在上午8:00~10:00高压氧治疗时间段,连续测量2d,取平均值.结果 2组人员在高压氧治疗环境中,无论血压还是脉搏都有波动,减压出舱时收缩压和舒张压与入舱时相比有升高趋势,而脉搏有减慢趋势,但各个时间段之间差异均无统计学意义( P>0.05).结论在2.2ATA治疗压力下,高压氧治疗环境对患者和陪舱人员的血压和脉搏无明显影响.%Objective To observe the influence of hyperbaric oxygen therapy ( HBOT ) environment on blood pressure and pulse of personnel in oxygen-cabin. Methods The blood pressure and pulse of 136 patients with HBOT and 30 accompanying personnel were measured by OmRon Automatic Electronic Device at entering oxygen-cabin, forcing oxygen uptake( 1. 8ATA), stable pressure oxygen uptake( 2. 2ATA ), stable pressure rest( 2. 2ATA ), oxygen uptake end ( 2. 2ATA )and coming out oxygen-cabin from the 8 a. m to 10 a. m. Results At different times during hyperbaric oxygen therapy process, there were small fluctuations in blood pressure and pulse, but the differences were not statistically significant ( P > 0. 05 ). Conclusion Under 2. 2ATA treatment pressure, hyperbaric oxygen therapy maybe has no significant effect on blood pressure and pulse of patients and accompanying personnel.

  15. Blood acid-base balance as a function of water oxygenation: a study at two different ambient CO2 levels in the dogfish, Scyliorhinus canicula.

    Science.gov (United States)

    Truchot, J P; Toulmond, A; Dejours, P

    1980-07-01

    In the unanesthetized dogfish, Scyliorhinus canicula, oxygen and carbon dioxide partial pressures and concentrations in inspired and expired water and the acid-base balance of arterial blood, pHa and PcCO2, were determined. Each dogfish was exposed to waters differing in oxygenation and in CO2 levels, which was controlled with a pH-CO2-stat device, for successive 2- to 3-h periods. The four ambient conditions were: normoxia-normocapnia (inspired PO2, PIO2 ca 160 Torr; PICO2 ca 0.3 Torr), hyperoxia-normocapnia (PIO2 ca 730 Torr), hyperoxia-hypercapnia (PICO2 ca 1.0 Torr); normoxia-hypercapnia. At both low and high ambient CO2, the inspired-expired O2 and CO2 concentration differences increased in hyperoxia. Ventilation was depressed, and concomitantly, PACO2 increased and the arterial plasma pH decreased. The hypercapnic acidosis was rapidly but only partially compensated by an increase of the plasma bicarbonate concentration. Due to the buffer action of carbonate in sea water, low and high ambient CO2 levels corresponded respectively to high and low values of the CO2 capacitance coefficient, betaWCO2. At both ambient oxygenation levels, the expired-inspired PCO2 difference was greater at low than at high betaWCO2. At a given ambient CO2 level, expired PCO2, PECO2, wash higher in hyperoxia than in normoxia; an effect more marked at low than at high betaWCO2. Thus, the water capacitance coeffcient betaWCO2 is an important factor determining PECO2 values and probably arterial blood acid-base balance. As a general conclusion, the acid-base balance of the arterial blood in the dogfish is very much dependent on the conditions of the oxygenation and acid-base balance of the ambient water which consequently should be carefully controlled. PMID:6771856

  16. Microbial community dynamics and methane, carbon dioxide, oxygen, and nitrous oxide concentrations in upland forest and riparian soils across a seasonal gradient of fully saturated soils to completely dried soils

    Science.gov (United States)

    Jones, R. T.; McGlynn, B. L.; McDermott, T.; Dore, J. E.

    2015-12-01

    Gas concentrations (CH4, CO2, N2O, and O2), soil properties (soil water content and pH), and microbial community composition were measured from soils at 32 sites across the Stringer Creek Watershed in the Tenderfoot Creek Experimental Forest 7 times between June 3, 2013 and September 20, 2013. Soils were fully saturated during the initial sampling period and dried down over the course of the summer. Soils and gas were sampled from 5cm and 20cm at each site and also at 50cm at eight riparian sites. In total, 496 individual soil samples were collected. Soil moisture ranged from 3.7% to fully saturated; soil pH ranged from 3.60 to 6.68. Methane concentrations in soils ranged from 0.426 ppm to 218 ppm; Carbon dioxide concentrations ranged from 550 ppm to 42,990 ppm; Nitrous oxide concentrations ranged from 0.220 ppm to 2.111 ppm; Oxygen concentrations ranged from 10.2% to 21.5%. Soil microbial communities were characterized by DNA sequences covering the V4 region of the 16S rRNA gene. DNA sequences were generated (~30,000,000 sequences) from the 496 soil samples using the Illumina MiSeq platform. Operational Taxonomic Units were generated using USEARCH, and representative sequences were taxonomically classified according the Ribosomal Database Project's taxonomy scheme. Analysis of similarity revealed that microbial communities found within a landscape type (high upland forest, low upland forest, riparian) were more similar than among landscape types (R = 0.600; ptests to determine how community structure co-varies with the soil environment and gas concentrations. All variables measured significantly co-varied with microbial community membership (pH: R = 0.712, p < 0.001; CO2: R = 0.578, p < 0.001; O2: R = 0.517, p < 0.001; Soil moisture: R = 0.408, p < 0.001; N2O: R = 0.218, p = 0.003; CH4: R = 0.195, p = 0.008). Despite the rather low co-variation between methane concentrations and microbial community composition, relative abundances of methanotrophic and

  17. Decrease of reactive-oxygen-producing granulocytes and release of IL-10 into the peripheral blood following leukocytapheresis in patients with active ulcerative colitis

    Institute of Scientific and Technical Information of China (English)

    Hiroyuki Hanai; Kenji Takai; Takayuki Iida; Ken Takeuchi; Fumitoshi Watanabe; Yasuhiko Maruyama; Masataka Kikuyama; Tatsuo Tanaka; Kenji Kondo; Kou Tanaka

    2005-01-01

    AIM: To investigate the clinical efficacy of leukocytapheresis (LCAP) in patients with active ulcerative colitis (UC), and to elucidate the mechanisms by determining the changes in the cytokine levels in the peripheral blood and of the functions of the peripheral blood leukocytes in these patients.METHODS: The subjects were 19 patients with active UC, with a mean clinical activity index (CAI) of 9.2. The LCAP was conducted using Cellsorba E. In each session of LCAP, 2-3 L of blood at the flow rate of 30-50 mL/min was processed. The treatment was carried out in approximately 1-h sessions, once a week, for 5-10 wk. Blood samples for determination of the cytokine levels were collected from the inflow side of the column (site of dehematization; at the start of LCAP) and outflow side of the column (at the end of LCAP). Blood samples for the determination of reactive-oxygen-producing cells were collected from the peripheral blood before and after LCAP.RESULTS: LCAP resulted in clinical improvement in all the 19 patients of UC recruited for this study. Remission (CAI: ≤4) was noted in 15 (79%) of the 19 patients. The blood level of the pro-inflammatory cytoline IL-6 was found to be decreased following treatment by LCAP, and the level of the anti-inflammatory cytokine IL-10 at the outflow side of the LCAP column was found to be significantly elevated as compared to that at the inflow side of the column. The reactive-oxygen-producing granulocytes in the peripheral blood of UC patients was increased as compared to that in healthy persons and the increase was found to be decreased following treatment by LCAP.CONCLUSION: LCAP exerted a high therapeutic efficacy in patients with active UC. Our findings suggest that LCAP is associated with enhanced production of the inhibitory cytokine IL-10 to indirectly inhibit the functions of the inflammatory leukocytes, and that inflammation is also considerably attenuated by the direct removal of reactiveoxygen-producing neutrophils from

  18. Hyperbaric oxygen therapy for cerebral blood flow and electroencephalogram in patients with acute cerebral infarction Choice for therapeutic occasion

    Institute of Scientific and Technical Information of China (English)

    Lei Chen; Fei Li; Dexiang Gu

    2007-01-01

    BACKGROUND: Hyperbaric oxygen (HBO) therapy increases blood oxygen content, changes cerebral blood flow (CBF) and cerebral metabolism. Its therapeutic effects on cerebrovascular disease have been fully confirmed, but the occasion for HBO therapy is still unclear.OBJECTIVE: To observe the therapeutic effects of HBO therapy at different time on CBF and electroencephalogram (EEG) in patients with acute cerebral infarction (CI).DESIGN: Randomized controlled trial.SETTING: Department of Neurology, Shidong Hospital, Yangpu District of Shanghai.PARTICIPANTS: Ninety-six inpatients with acute CI, admitted to Department of Neurology, Shidong Hospital, Yangpu District of Shanghai from January 2001 to December 2006, were involved in this experiment. The involved participants met the diagnosis criteria of acute CI and confirmed by skull CT or MRI. They all were patients with moderate CI (16- 30 points) according to neurologic deficit score formulated by Chinese Medical Association. Informed consents of detected items and therapeutic regimen were obtained from all the involved participants. They were randomized into two groups with 48 in each:early-stage treatment group and advanced-stage treatment group. Among the 48 patients in the early-stage treatment group, 21 male and 27 female, aged 53 -68 years, 22 patients were found with basal ganglia infarction, 10 with brain lobe infarction, 16 with multiple infarction, 27 accompanied with hypertension and 2 accompanied with diabetes mellitus. Among the 48 patients in the advanced-stage treatment group, 23 male and 25 female, aged 52 - 71 years, 25 patients were found with basal ganglia infarction, 10 with brain lobe infarction, 12 with multiple infarction, 1 with brain stem infarction, 28 accompanied with hypertension and 1 accompanied with diabetes mellitus.METHODS: After admission, patients of two groups received routine drug treatment. ① Patients in the early-stage treatment group and advanced-stage treatment group began to

  19. Serum albumin--a non-saturable carrier

    DEFF Research Database (Denmark)

    Brodersen, R; Honoré, B; Larsen, F G

    1984-01-01

    The shape of binding isotherms for sixteen ligands to human serum albumin showed no signs of approaching saturation at high ligand concentrations. It is suggested that ligand binding to serum albumin is essentially different from saturable binding of substrates to enzymes, of oxygen to haemoglobin......, etc. Binding to serum albumin appears to be non-saturable. Udgivelsesdato: 1984-Feb...

  20. Increases in arterial blood oxygen during exercise in the lemon shark (Negaprion brevirostris)

    DEFF Research Database (Denmark)

    BUSHNELL, PG; LUTZ, PL; STEFFENSEN, JF;

    1982-01-01

    Polyethylene cannulae were implanted in pre- and post-branchial blood vessels allowing nonstressful blood sampling over a variety of activity ranges in an active tropical elasmobranch, the lemon shark (Negaprion brevirostris). TheP 50 was found to be 11.8 Torr at 24°C and pH of 7.7. A Bohr shift of...

  1. Autoradiographic determination of regional cerebral blood flow and metabolism in conscious rats after fluid resuscitation from haemorrhage with a haemoglobin-based oxygen carrier.

    Science.gov (United States)

    Waschke, K F; Albrecht, D M; van Ackern, K; Kuschinsky, W

    1994-10-01

    The effects of resuscitation fluids on the brain have been investigated in previous studies by global measurements of cerebral blood flow and metabolism. In this study we have examined the effects of a novel haemoglobin-based oxygen carrier on local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) after resuscitation from a volume-controlled haemorrhage of 30 min (3.0 ml/100 g body weight) with ultrapurified, polymerized, bovine haemoglobin (UPBHB). LCBF and LCGU were measured in 34 brain structures of conscious rats 2 h after resuscitation using quantitative iodo(14C)antipyrine and 2-(14C)-deoxy-D-glucose methods. The data were compared with a control group without haemorrhage and fluid resuscitation. In the haemorrhage group, LCBF increased after resuscitation by 12-56% in the different brain structures (mean 36%). LCGU changed less (0 to +18%, mean +9%). In the control group there was a close relationship between LCGU and LCBF (r = 0.95). After fluid resuscitation the relationship was preserved (r = 0.95), although it was reset at a higher ratio of LCBF to LCGU (P < 0.05). We conclude that fluid resuscitation of a 30 min volume-controlled haemorrhage using the haemoglobin-based oxygen carrier, UPBHB, induced a moderate degree of heterogeneity in the resulting changes of LCGU and LCBF. Local disturbances of cerebral blood flow or metabolism were not observed. PMID:7999496

  2. Outcomes of acute exacerbations in COPD in relation to pre-hospital oxygen therapy

    DEFF Research Database (Denmark)

    Ringbaek, Thomas J; Terkelsen, Jakob; Lange, Peter

    2015-01-01

    . METHODS: In an audit of 405 consecutive patients with AECOPD arriving by ambulance to Hvidovre Hospital, details of transit time, oxygen administration, saturation, and arterial blood gases were registered. Outcomes were respiratory acidosis, need of supported ventilation, length of hospitalisation, and...

  3. A theoretical model for the effects of reduced hemoglobin-oxygen affinity on tumor oxygenation

    International Nuclear Information System (INIS)

    Purpose: To develop a theoretical model for oxygen delivery to tumors, and to use the model to simulate the effects of changing the affinity of hemoglobin for oxygen on tumor oxygenation. Methods and Materials: Hemoglobin affinity is expressed in terms of P50, the partial pressure of oxygen (Po2) at half saturation. Effects of changing P50 on arterial Po2 are predicted using an effective vessel approach to describe diffusive oxygen transport in the lungs, assuming fixed systemic oxygen demand and fixed blood flow rate. The decline in oxygen content of blood as it flows through normal tissue before entering the tumor region is assumed fixed. The hypoxic fraction of the tumor region is predicted using a three-dimensional simulation of diffusion from a network of vessels whose geometry is derived from observations of tumor microvasculature in the rat. Results: In air-breathing rats, predicted hypoxic fraction decreases with moderate increases in P50, but increases with further increases of P50, in agreement with previous experimental results. In rats breathing hyperoxic gases, and in humans breathing either normoxic or hyperoxic gases, increased P50 is predicted to improve tumor oxygenation. Conclusions: The results support the administration of synthetic agents to increase P50 during radiation treatment of tumors

  4. Effects of exercise mode on the peak oxygen uptake and blood lactate response in boys aged 11-12 years

    Directory of Open Access Journals (Sweden)

    Fabiana Andrade Machado

    2006-09-01

    Full Text Available The objective of this study was to analyze the effects of exercise mode (running x cycling on the indexesrelated to aerobic fitness (VO2peak and blood lactate response to exercise in children. Participated of this study 20 active boys apparently healthy (age = 11.48 + 0.41 yr.; body mass = 41.38 + 10.45 kg; stature = 147.45 + 6.56 cm, with sexual maturational level 1 and 2 (pubic hair, which performed two incremental tests, with stages of 3 minutes until voluntary exhaustion, in treadmill (TR and cycle ergometer (CE, to the determination of peak oxygen uptake (VO2peak and lactate threshold (LT. The VO2peak was determined through the higher value obtained at intervals of 15 seconds. The LT was determined as the exercise intensity where the first and sustained increase of blood lactate above rest level occurred. The VO2peak (45.16 + 5.98 x 42.93 + 7.51 ml/kg/min, maximal heart rate (196.5 + 6.98 x 187.3 + 9.27 bpm, VO2 at LL (31.82 + 10.09 x 25.19 + 7.36 ml/kg/min and HR at LL (150.5 + 17.75 x 131.3 + 12.98 bpm were significantly higher in TR than CE, respectively. Thus, similar to adults, boys of 11 to 12 years present higher aerobic indexes (submaximal and maximal in running than cycling, which can haveimportant implications for healthy professionals that utilize exercise for the healthy promotion, rehabilitation and experimental designs. RESUMO O objetivo deste estudo foi analisar os efeitos do modo de exercício (corrida x ciclismo sobre os índices relacionados com a aptidão aeróbia (VO2pico e resposta de lactato ao exercício em crianças. Participaram doestudo 20 meninos, aparentemente saudáveis e ativos (idade = 11,48 + 0,41 anos; massa corporal = 41,38 + 10,45 kg; estatura = 147,45 + 6,56 cm, com níveis de maturação sexual 1 e 2 (pilosidade pubiana, que realizaram dois testes incrementais, com estágios de 3 minutos até a exaustão voluntária, em esteira rolante (ER e bicicleta ergométrica (BE, para a determinação do pico do

  5. Gas exchange and the coagulation system of the blood during the effect on the body of high concentrations of oxygen and carbon dioxide

    Science.gov (United States)

    Palosh, L.; Agadzhanyan, N. A.; Davydov, G. A.; Rybakov, B. K.; Sergiyenko, A. S.

    1974-01-01

    Maximum permissible concentrations of oxygen and carbon dioxide in a controlled atmosphere were determined by evaluating their effects on human gas exchange, blood coagulation, and tolerances to acute hypoxia, acceleration, and physical loads. It was found that functional disturbances depend on the concentration of respiratory gases and the length of stay in an altered atmosphere. By changing the atmospheric composition and by bringing the gaseous environment into accordance with the work and rest regimen and energy expenditures, the general reactivity of the body changes favorably.

  6. Relationships between human vitality and mitochondrial respiratory parameters, reactive oxygen species production and dNTP levels in peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Maynard, Scott; Keijzers, Guido; Gram, Martin; Desler, Claus; Bendix, Laila; Budtz-Jørgensen, Esben; Molbo, Drude; Croteau, Deborah L; Osler, Merete; Stevnsner, Tinna V.; Rasmussen, Lene Juel; Dela, Flemming; Avlund, Kirsten; Bohr, Vilhelm

    2013-01-01

    . Therefore, we measured a number of cellular parameters related to mitochondrial activity in peripheral blood mononuclear cells (PBMCs) isolated from middle-aged men, and tested for association with vitality. These parameters estimate mitochondrial respiration, reactive oxygen species (ROS) production, and......Low vitality (a component of fatigue) in middle-aged and older adults is an important complaint often identified as a symptom of a disease state or side effect of a treatment. No studies to date have investigated the potential link between dysfunctional mitochondrial ATP production and low vitality...

  7. Relationships between human vitality and mitochondrial respiratory parameters, reactive oxygen species production and dNTP levels in peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Maynard, Scott; Keijzers, Guido; Gram, Martin; Madsen, Claus Desler; Bendix, Laila; Budtz-Jørgensen, Esben; Molbo, Drude; Croteau, Deborah L; Osler, Merete; Stevnsner, Tinna V.; Rasmussen, Lene Juel; Dela, Flemming; Avlund, Kirsten; Bohr, Vilhelm A

    . Therefore, we measured a number of cellular parameters related to mitochondrial activity in peripheral blood mononuclear cells (PBMCs) isolated from middle-aged men, and tested for association with vitality. These parameters estimate mitochondrial respiration, reactive oxygen species (ROS) production, and......Low vitality (a component of fatigue) in middle-aged and older adults is an important complaint often identified as a symptom of a disease state or side effect of a treatment. No studies to date have investigated the potential link between dysfunctional mitochondrial ATP production and low vitality...

  8. Anemia and Oxygen Delivery.

    Science.gov (United States)

    Bliss, Stuart

    2015-09-01

    Clinical assessment of tissue oxygenation is challenging. Anemia reflects a decreased oxygen carrying capacity of the blood and its significance in the perioperative setting relates largely to the associated risk of insufficient oxygen delivery and cellular hypoxia. Until meaningful clinical measures of tissue oxygenation are available in veterinary practice, clinicians must rely on evaluation of a patient's hemodynamic and ventilatory performance, along with biochemical and hemogasometric measurements. Blood transfusion is used commonly for treatment of perioperative anemia, and may improve tissue oxygenation by normalizing the rheologic properties of blood and enhancing perfusion, independent of increases in oxygen carrying capacity. PMID:26033442

  9. Effects of carvedilol and propranolol on circulatory regulation and oxygenation in cirrhosis

    DEFF Research Database (Denmark)

    Hobolth, Lise; Bendtsen, Flemming; Hansen, Erik F; Møller, Søren

    2014-01-01

    =16) or propranolol (n=13). Cardiac, systemic and splanchnic parameters along with oxygen saturation and plasma renin were measured at inclusion and after 3 months. RESULTS: Arterial blood pressure, heart rate, and cardiac output decreased equally, central circulation time and systemic vascular...... oxygen gradient remained constant in both groups. Hepatic venous pressure gradient decreased equally in the carvedilol and propranolol groups (-17% and -20%, non significant). CONCLUSIONS: Systemic haemodynamics and pulmonary effects of carvedilol and propranolol are modest and this study could not...

  10. Changes in blood hemoglobin and blood gases PaO2 and PaCO2 in severe COPD overa three-year telemonitored program of long-term oxygen treatment

    Directory of Open Access Journals (Sweden)

    Dal Negro Roberto W

    2012-07-01

    Full Text Available Abstract Background Information on the effects of long-term oxygen treatment (LTOT on blood hemoglobin (Hb in severe COPD are limited. The aim was to assess blood Hb values in severe COPD, and investigate the time-course of both Hb and blood gas changes during a 3-year telemetric LTOT. Methods A cohort of 132 severe COPD patients (94 males; 71.4 years ± 8.8 sd, newly admitted to the tele-LTOT program, was investigated. Subjects were divided according to their original blood Hb: group A: 2 and PaCO2 (mmHg, SaO2 (%, and BMI were measured at LTOT admission (t0, and at least quarterly over three years (t1-t3. Wilcoxon test was used to compare t0 vs. t1 values; linear regression to assess a possible Hb-BMI relationship; ANOVA to compare changes in Hb time-courses over the 3 years. Results LTOT induced a systematic increase of PaO2, and changes were significant since the first year (from 52.1 mmHg ± 6.6sd to 65.1 mmHg ± 8.7 sd, p 2 were quite similar. Comparable and equally significant trends were seen in all subgroups (p 2 dropped within the first year of LTOT (from 49.4 mmHg ± 9.1sd to 45.9 mmHg ±7.5 sd, p 0-t1 comparison proved significant (p 2 decline over the remaining two years (p  15 g/dl (ANOVA p 2, PaCO2 and SaO2 dramatically improved. In anemic subjects effects were smaller and slower, oxygenation being equally ameliorated by LTOT. Conclusions LTOT effects on Hb and PaCO2 are regulated by an Hb-dependent gradient which seems independent of the original impairment of blood gases and of effects on oxygenation.

  11. Effect of hyperbaric oxygen therapy on whole blood cyanide concentrations in carbon monoxide intoxicated patients from fire accidents

    DEFF Research Database (Denmark)

    Lawson-Smith, Pia; Jansen, Erik C; Hilsted, Linda;

    2010-01-01

    Hydrogen cyanide (HCN) and carbon monoxide (CO) may be important components of smoke from fire accidents. Accordingly, patients admitted to hospital from fire accidents may have been exposed to both HCN and CO. Cyanide (CN) intoxication results in cytotoxic hypoxia leading to organ dysfunction and...... possibly death. While several reports support the use of hyperbaric oxygen therapy (HBO) for the treatment of severe CO poisoning, limited data exist on the effect of HBO during CN poisoning. HBO increases the elimination rate of CO haemoglobin in proportion to the increased oxygen partial pressure and...

  12. Increased plasma noradrenaline concentration in patients with chronic obstructive lung disease: relation to haemodynamics and blood gases

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Christensen, N J; Kok-Jensen, A;

    1980-01-01

    . Plasma noradrenaline (NA) concentration averaged 0.51 ng/ml and was inversely correlated to arterial oxygen saturation and mixed venous oxygen saturation, and positively correlated to arterial carbon dioxide tension and mean pulmonary arterial pressure. Oxygen inhalation did not change plasma NA...... present. Plasma adrenaline concentration was normal. The results point to enhanced sympathetic nervous activity in patients with chronic obstructive lung disease, probably caused by the deranged blood gases. The pulmonary haemodynamic changes and increased pulse rate may, at least partly, be due to...

  13. Cord blood testing

    Science.gov (United States)

    ... to evaluate the oxygen, carbon dioxide, and pH levels) Blood sugar level Blood type and Rh Complete blood count ( ... means you have a blood infection (septicemia). High levels of blood sugar (glucose) in the cord blood may be found ...

  14. Can abdominal NIRS detect changes in intestinal blood flow and risk of NEC in premature piglets?

    Science.gov (United States)

    Necrotizing enterocolitis (NEC) is major gut disease in preterm newborns. Intestinal ischemia may be an early contributing factor that precipitates NEC. Near-infrared spectroscopy (NIRS) is a non-invasive method of measuring local tissue oxygen saturation and indicator of blood flow. Our aim was t...

  15. Calibration of a prototype NIRS oximeter against two commercial devices on a blood-lipid phantom

    DEFF Research Database (Denmark)

    Hyttel-Sorensen, Simon; Kleiser, Stefan; Wolf, Martin; Greisen, Gorm

    2013-01-01

    In a blood-lipid liquid phantom the prototype near-infrared spectroscopy oximeter OxyPrem was calibrated against the INVOS® 5100c adult sensor in respect to values of regional tissue oxygen haemoglobin saturation (rStO2) for possible inclusion in the randomised clinical trial - SafeBoosC. In...

  16. The role of perfusion in the oxygen extraction capability of skin and skeletal muscle.

    Science.gov (United States)

    Thorn, Clare E; Shore, Angela C

    2016-05-15

    Oxygen extraction (OE) by all cells is dependent on an adequate supply of oxygen in proximal blood vessels and the cell's need and ability to uptake that oxygen. Here the role of blood flow in regulating OE in skin and skeletal muscle was investigated in lean and obese men. OE was derived by two optical reflectance spectroscopy techniques: 1) from the rate of fall in mean blood saturation during a 4 min below knee arterial occlusion, and thus no blood flow, in calf skin and skeletal muscle and 2) in perfused, unperturbed skin, using the spontaneous falls in mean blood saturation induced by vasomotion in calf and forearm skin of 24 subjects, 12 lean and 12 obese. OE in perfused skin was significantly higher in lean compared with obese subjects in forearm (Mann-Whitney, P obese subjects no longer differed (P = 0.23, not significant). In contrast in skeletal muscle with arterial occlusion and no blood flow, the difference in OE between lean and obese subjects occurred, with obese subjects exhibiting significantly higher OE (P obesity. In resting skeletal muscle other mechanism(s), independent of blood flow, are implicated in oxygen extraction. PMID:27016577

  17. Improved tumor oxygenation and survival in glioblastoma patients who show increased blood perfusion after cediranib and chemoradiation

    OpenAIRE

    Batchelor, Tracy T.; Gerstner, Elizabeth R.; Emblem, Kyrre E; Dan G Duda; Kalpathy-Cramer, Jayashree; Snuderl, Matija; Ancukiewicz, Marek; Polaskova, Pavlina; Pinho, Marco C.; Jennings, Dominique; Plotkin, Scott R.; Chi, Andrew S.; Eichler, April F.; Dietrich, Jorg; Hochberg, Fred H.

    2013-01-01

    This study demonstrates that antiangiogenic therapy increases tumor blood perfusion in a subset of newly diagnosed glioblastoma patients, and that it is these patients who survive longer when this expensive and potentially toxic therapy is combined with standard radiation and chemotherapy. This study provides fresh insights into the selection of glioblastoma patients most likely to benefit from antiangiogenic treatments.

  18. Acute effects of nicotine and smoking on blood flow, tissue oxygen, and aerobe metabolism of the skin and subcutis

    DEFF Research Database (Denmark)

    Sørensen, Lars Tue; Jørgensen, Stig; Petersen, Lars Jelstrup;

    2009-01-01

    BACKGROUND: Nicotine released from tobacco smoke causing reduction in blood flow has been suggested as causative for postoperative wound complications in smokers, but the mechanism remains unknown. MATERIALS AND METHODS: In eight healthy male smokers and eight ex-smokers, the cutaneous and...

  19. Modeling oxygenation in venous blood and skeletal muscle in response to exercise using near-infrared spectroscopy

    OpenAIRE

    Lai, Nicola; Zhou, Haiying; Saidel, Gerald M.; Wolf, Martin; McCully, Kevin; Gladden, L. Bruce; Cabrera, Marco E.

    2009-01-01

    Noninvasive, continuous measurements in vivo are commonly used to make inferences about mechanisms controlling internal and external respiration during exercise. In particular, the dynamic response of muscle oxygenation (\\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in ...

  20. Simultaneous measurement of cerebral blood flow and oxygen extraction fraction by positron emission tomography: theoretical study and experimental evidence of cerebral blood flow measurement with the C15O2 continuous inhalation technique

    International Nuclear Information System (INIS)

    The method of the continuous inhalation technique of oxygen-15 labelled CO2 coupled with positron emission tomography for the measurement of cerebral blood flow (C.B.F.) is described. An indirect experimental verification that this technique allowed the measurement of C.B.F. has been carried out in baboons by showing the expected change in the measured parameter with variations in the PaCO2. A critical investigation of the C15O2 model was performed. The amount of tracer present in the cerebral vascular pool has a negligible effect on C.B.F. value. The use of a mean brain-blood partition coefficient of water instead of that specific to gray or to white matter is commented upon, and its influence on the final C.B.F. value is studied. Lastly, the problem of the limited diffusion of water across the blood-brain-barrier is discussed. The study of the combined effects of gray-white mixing and limited wates extraction of the C.B.F. value shows that the C15O2 technique tends to understimate real C.B.F., and that this error is more severe with high flows and even gray white mixing. These limitations do not depart from the possibility to estimate in the same brain locus not only C.B.F. but oxygen utilization as well by the consecutive inhalation of C15O2 and 15O2. The advantages of this possibility has already been shown in a number of clinical studies

  1. Artificial blood

    Directory of Open Access Journals (Sweden)

    Sarkar Suman

    2008-01-01

    Full Text Available Artificial blood is a product made to act as a substitute for red blood cells. While true blood serves many different functions, artificial blood is designed for the sole purpose of transporting oxygen and carbon dioxide throughout the body. Depending on the type of artificial blood, it can be produced in different ways using synthetic production, chemical isolation, or recombinant biochemical technology. Development of the first blood substitutes dates back to the early 1600s, and the search for the ideal blood substitute continues. Various manufacturers have products in clinical trials; however, no truly safe and effective artificial blood product is currently marketed. It is anticipated that when an artificial blood product is available, it will have annual sales of over $7.6 billion in the United States alone.

  2. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  3. Broadband diffuse optical spectroscopy assessment of hemorrhage- and hemoglobin-based blood substitute resuscitation

    OpenAIRE

    Lee, Jangwoen; Kim, Jae G.; Mahon, Sari; Tromberg, Bruce J; Mukai, David; Kreuter, Kelly; Saltzman, Darin; Patino, Renee; Goldberg, Robert; Brenner, Matthew

    2009-01-01

    Hemoglobin-based oxygen carriers (HBOCs) are solutions of cell-free hemoglobin (Hb) that have been developed for replacement or augmentation of blood transfusion. It is important to monitor in vivo tissue hemoglobin content, total tissue hemoglobin [THb], oxy- and deoxy-hemoglobin concentrations ([OHb], [RHb]), and tissue oxygen saturation (StO2=[OHb]/[THb]×100%) to evaluate effectiveness of HBOC transfusion. We designed and constructed a broadband diffuse optical spectroscopy (DOS) prototype...

  4. Non-arterial assessment of blood gas status in patients with chronic pulmonary disease.

    OpenAIRE

    Elborn, J. S.; Finch, M B; Stanford, C. F.

    1991-01-01

    Assessment of blood gas status is important in the management of patients with chronic pulmonary disease. Arterial puncture is often painful and may damage the arterial wall. Measurement of oxygen saturation by transcutaneous oximetry offers a non-invasive alternative to arterial methods but does not allow assessment of partial pressure of carbon dioxide. We have examined the value of oximetry and dorsal hand venous carbon dioxide as an alternative to arterial puncture. Transcutaneous oxygen ...

  5. Left anterior descending coronary artery blood flow and left ventricular unloading during extracorporeal membrane oxygenation support in a swine model of acute cardiogenic shock.

    Science.gov (United States)

    Brehm, Christoph; Schubert, Sarah; Carney, Elizabeth; Ghodsizad, Ali; Koerner, Michael; McCoach, Robert; El-Banayosy, Aly

    2015-02-01

    The impact of extracorporeal membrane oxygenation (ECMO) support on coronary blood flow and left ventricular unloading is still debated. This study aimed to further characterize the influence of ECMO on coronary artery blood flow and its ability to unload the left ventricle in a short-term model of acute cardiogenic shock. Seven anesthetized pigs were intubated and then underwent median sternotomy and cannulation for venoarterial (VA) ECMO. Flow in the left anterior descending (LAD) artery, left atrial pressure (LAP), left ventricular end-diastolic pressure (LVEDP), and mean arterial pressure (MAP) were measured before and after esmolol-induced cardiac dysfunction and after initiating VA-ECMO support. Induction of acute cardiogenic shock was associated with short-term increases in LAP from 8 ± 4 mm Hg to 18 ± 14 mm Hg (P = 0.9) and LVEDP from 5 ± 2 mm Hg to 13 ± 17 mm Hg (P = 0.9), and a decrease in MAP from 63 ± 16 mm Hg to 50 ± 24 mm Hg (P = 0.3). With VA-ECMO support, blood flow in the LAD increased from 28 ± 25 mL/min during acute unsupported cardiogenic shock to 67 ± 50 mL/min (P = 0.003), and LAP and LVEDP decreased to 8 + 5 mm Hg (P = 0.7) and 5 ± 3 mm Hg (P = 0.5), respectively. In this swine model of acute cardiogenic shock, VA-ECMO improved coronary blood flow and provided some degree of left ventricular unloading for the short duration of the study. PMID:24935151

  6. Effects of Intensified Vasodilatory Antihypertensive Treatment on Renal Function, Blood supply and Oxygenation in Chronic Kidney Disease

    DEFF Research Database (Denmark)

    Khatir, Dinah Sherzad; Pedersen, Michael; Ivarsen, Per;

    2015-01-01

    Background: Progression of Chronic kidney disease (CKD) may result from tissue hypoxia induced by small artery structural narrowing, with increased renal vascular resistance (RVR) and impaired blood supply. We investigated whether vasodilating therapy (VT) is superior to non-vasodilating therapy...... increased by 39% (P<0.01) while RVR remained unchanged. Cortical and medullary R2* values were not affected by VT and nonVT. After 18 months GFR decline was similar in the two groups (3.0 vs. 3.3 ml/min/1.73 m2). Conclusions: In CKD, long-term VT reduced both peripheral and RVR, but was not associated with...

  7. Partial blood oxygen pressure and pulmonary ventilation changes in patients with fractures with a view to traumatic fat embolism development.

    Science.gov (United States)

    Kroupa, J; Kusák, I

    1983-01-01

    The body's response to the effects of mechanical injury, taking the form of shock during the first hours and the onset of fat embolism in the subsequent period, is substantially higher in patients with multiple or associated injuries, both as regards the severity of manifestations and prognostic risk. Also the death rate due to this sort of complication is seen rising. Two groups of injured persons with isolated (n = 33) and multiple fractures (n = 33) were used to show that dynamic follow-up of PaO2 in the blood could serve as a criterion of the risk of fat embolism development in the body and, in particular, as a prognostic criterion for the progress of fat embolism. Special point was made of findings demonstrating a time relationship between PaO2 deterioration in the early post-injury period (up to 24-36 hours) as compared with the period of 48-72 hours after the injury. PaO2 is seen dropping rapidly in injured persons showing signs of fat embolism syndrome development. The decrease can be recorded as early as the free interval phase, i.e. prior to the manifestation of the clinical signs of fat embolism. The findings of low PaO2 levels in the blood are in accordance with respiratory ventilation disturbances and impaired diffusion documented in our investigation. PMID:6409565

  8. Gluon saturation in a saturated environment

    Science.gov (United States)

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan

    2011-07-01

    A bootstrap equation for self-quenched gluon shadowing leads to a reduced magnitude of broadening for partons propagating through a nucleus. Saturation of small-x gluons in a nucleus, which has the form of transverse momentum broadening of projectile gluons in pA collisions in the nuclear rest frame, leads to a modification of the parton distribution functions in the beam compared with pp collisions. In nucleus-nucleus collisions all participating nucleons acquire enhanced gluon density at small x, which boosts further the saturation scale. Solution of the reciprocity equations for central collisions of two heavy nuclei demonstrate a significant, up to several times, enhancement of QsA2, in AA compared with pA collisions.

  9. Gluon saturation in a saturated environment

    International Nuclear Information System (INIS)

    A bootstrap equation for self-quenched gluon shadowing leads to a reduced magnitude of broadening for partons propagating through a nucleus. Saturation of small-x gluons in a nucleus, which has the form of transverse momentum broadening of projectile gluons in pA collisions in the nuclear rest frame, leads to a modification of the parton distribution functions in the beam compared with pp collisions. In nucleus-nucleus collisions all participating nucleons acquire enhanced gluon density at small x, which boosts further the saturation scale. Solution of the reciprocity equations for central collisions of two heavy nuclei demonstrate a significant, up to several times, enhancement of QsA2, in AA compared with pA collisions.

  10. Studies of cerebral blood flow, cerebral oxygen metabolism, cerebral glucose metabolism, and tissue pH in human acute cerebral infarction using positron emission tomography

    International Nuclear Information System (INIS)

    This preliminary PET study was designed to investigate physiological and biochemical changes in acute cerebral infarction by positron emission tomography (PET). PET studies were performed in six patients with acute cerebral infarction within 48 hours after onset of stroke using continuous inhalation of C15O2 for cerebral blood flow (CBF), 15O2 for cerebral metabolic rate for oxygen (CMRO2), 11CO for cerebral blood volume, the intravenous injection of 11C-dimethyloxazolidinedione for tissue pH and the intravenous injection of 18F-fluorodeoxyglucose for cerebral metabolic rate for glucose (CMRGlu). Metabolic coupling index (MCI) image was made from CBF image and CMRGlu image to investigate relation between CBF and CMRGlu. Aslo oxygen glucose index (OGI) image was made from CMRO2 image and CMRG lu image to investigate relation between CMRO2 and CMRGlu. Preliminary resul ts demonstrate that reduction of CBF, CMRO2, and CMRGlu in the affected co rtex except for reperfusion case. Increase of OER was recognized four of six cases. Patterns of MCI and OGI in the cortex which CMRO2 value is less than 65 μmol/100g/min were different from those in the cortex which CMRO2 value is more than 65. MCI of the affected cortex (CMRO22>=65). OGI of the affected cortex (CMRO22>=65). Two patients showed decrease of tissue pH and reperfusion case showed increase of tissue pH in infarcted area as compared to contralateral cortex. In addition it was suggested that threshold of CBF for tissue pH was approximately 14ml/100g/min. (J.P.N.)

  11. Airborne particulate matter PM2.5 from Mexico City affects the generation of reactive oxygen species by blood neutrophils from asthmatics: an in vitro approach

    Directory of Open Access Journals (Sweden)

    Ceballos Guillermo

    2009-06-01

    Full Text Available Abstract Background The Mexico City Metropolitan Area is densely populated, and toxic air pollutants are generated and concentrated at a higher rate because of its geographic characteristics. It is well known that exposure to particulate matter, especially to fine and ultra-fine particles, enhances the risk of cardio-respiratory diseases, especially in populations susceptible to oxidative stress. The aim of this study was to evaluate the effect of fine particles on the respiratory burst of circulating neutrophils from asthmatic patients living in Mexico City. Methods In total, 6 subjects diagnosed with mild asthma and 11 healthy volunteers were asked to participate. Neutrophils were isolated from peripheral venous blood and incubated with fine particles, and the generation of reactive oxygen species was recorded by chemiluminescence. We also measured plasma lipoperoxidation susceptibility and plasma myeloperoxidase and paraoxonase activities by spectrophotometry. Results Asthmatic patients showed significantly lower plasma paraoxonase activity, higher susceptibility to plasma lipoperoxidation and an increase in myeloperoxidase activity that differed significantly from the control group. In the presence of fine particles, neutrophils from asthmatic patients showed an increased tendency to generate reactive oxygen species after stimulation with fine particles (PM2.5. Conclusion These findings suggest that asthmatic patients have higher oxidation of plasmatic lipids due to reduced antioxidant defense. Furthermore, fine particles tended to increase the respiratory burst of blood human neutrophils from the asthmatic group. On the whole, increased myeloperoxidase activity and susceptibility to lipoperoxidation with a concomitant decrease in paraoxonase activity in asthmatic patients could favor lung infection and hence disrupt the control of asthmatic crises.

  12. Respiratory properties of blood and hemoglobin solutions from the piranha

    DEFF Research Database (Denmark)

    Wood, S.C.; Weber, Roy E.; Powers, D.

    1979-01-01

    1. Respiratory properties of piranha blood are distinguished from those of other fish primarily by the high CO2 buffering capacity (?HCO3/-?pH= 19.6mmol/l for oxygenated blood and 39.1 mmol/l for deoxygenated blood). 2. The concentration of nucleoside triphosphates (NTP) and the half-saturation t......1. Respiratory properties of piranha blood are distinguished from those of other fish primarily by the high CO2 buffering capacity (?HCO3/-?pH= 19.6mmol/l for oxygenated blood and 39.1 mmol/l for deoxygenated blood). 2. The concentration of nucleoside triphosphates (NTP) and the half......-saturation tension (P50) of whole blood were found to be inversely related to body size. 3. The higher P50 in smaller fish, analogous to values obtained in previous studies involving interspecies comparisons, could be adaptive to a higher weight-specific metabolic rate. 4. Both ATP and guanosine triphosphate (GTP...

  13. Oxygenation of the calf muscle during an incremental, intermittent walking exercise assessed by NIRS

    Science.gov (United States)

    Härtel, S.; Kutzner, C.; Schneider, D.; Grieger, S.; Neumaier, M.; Kohl-Bareis, M.

    2011-07-01

    We use near infrared spectroscopy (NIRS) for the non-invasive assessment of calf oxygenation during a new walking protocol in healthy subjects of different fitness levels. The protocol increases the exercise power by an increase of the skew rather than speed, and the incremental power steps are intermitted by a 30 s rest which serves for blood sampling. The NIRS measurement parameter of tissue oxygenation are discussed, and a high correlation of the oxygen saturation (tissue oxygenation index) difference between exercise and rest period with exercise power is observed. This difference parameter can be interpreted as strongly linked to blood flow rather than oxygenation. This finding is supported by comparison with spirometry data. The effect of training is discussed. The exercise protocol is suited for testing unfit, or older subjects and the data discussed here servers as a test for a larger trial with heart clinic patients.

  14. Effect of oxygen plasma treatment on surface charge and wettability of PVC blood bag-In vitro assay

    International Nuclear Information System (INIS)

    Wettability and zeta potential studies were performed to characterize the hydrophobicity and surface charge of PVC blood bag samples and evaluate the effect of these properties on fibroblast cells growth. The surface properties of PVC and plasma treated PVC were compared by water drop contact angle and zeta potential measurement. Light microscopy was used to study the behavior of cell attachment and growth on these surfaces. Water drop contact angle measurement shows that the plasma treated PVC becomes more hydrophilic and wettability increased. Zeta potential and in vitro cell culture measurements noticed that the plasma treated PVC surface is more negatively charge and consequently attachment of the L929 fibroblast cells decreased on this surface

  15. Influence of oxygen on asexual blood cycle and susceptibility of Plasmodium falciparum to chloroquine: requirement of a standardized in vitro assay

    Directory of Open Access Journals (Sweden)

    Minodier Philippe

    2007-04-01

    Full Text Available Abstract Objective The main objective of this study was to assess the influence of gas mixtures on in vitro Plasmodium falciparum growth and 50% inhibitory concentration (IC50 for chloroquine. Methods The study was performed between February 2004 and December 2005. 136 Plasmodium falciparum isolates were used to evaluate gas mixtures effect on IC50 for chloroquine by isotopic microtest. The oxygen effect on asexual blood cycle of 3D7 and W2 clones was determined by thin blood smears examination and tritiated hypoxanthine uptake. Results From 5% O2 to 21% O2 conditions, no parasiticide effect of O2 concentration was observed in vitro on the clones 3D7 and W2. A parasitostatic effect was observed during the exposure of mature trophozoïtes and schizonts at 21% O2 with an increase in the length of schizogony. The chloroquine IC50 at 10% O2 were significantly higher than those at 21% O2, means of 173.5 nM and 121.5 nM respectively (p in vitro resistant to chloroquine (IC50 > 100 nM at 10% O2, 17 were sensitive to chloroquine (IC50 2. Conclusion Based on these results, laboratories should use the same gas mixture to realize isotopic microtest. Further studies on comparison of isotopic and non-isotopic assays are needed to establish a standardized in vitro assay protocol to survey malaria drug resistance.

  16. High content of pyridinic- and pyrrolic-nitrogen-modified carbon nanotubes derived from blood biomass for the electrocatalysis of oxygen reduction reaction in alkaline medium

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted -- Highlights: •An ORR electrocatalyst was fabricated from blood biomass and carbon nanotube. •The N-CNT catalyst exhibits good ORR activity, methanol resistance and stability. •The pyrolysis process produces high contents of pyridinic and pyrrolic N species. •The pyridinic-N group may play more important role in the active sites for ORR. -- Abstract: Here we present a facile synthetic route to design nitrogen-doped nanostructured carbon-based electrocatalyst for oxygen reduction reaction (ORR) by the copyrolysis of blood biomass from pig and carbon nanotubes (CNTs) at high temperatures. The nitrogen-doped CNTs obtained at 800 °C not only results in excellent ORR activity with four-electron transfer selectivity in alkaline medium, but also exhibits superior methanol-tolerant property and long-term stability. It is confirmed that high-temperature pyrolysis processes can facilitate to produce higher contents of pyridinic- and pyrrolic-N binding groups in electrocatalysts, contributing to the enhancement of ORR performance in terms of onset potential, half-wave potential, and limited current density. We also propose that the planar-N configuration may be the active site that is responsible for the improved ORR electrocatalytic performance. The straight-forward and cheap synthesis of the active and stable electrocatalyst makes it a promising candidate for electrochemical power sources such as fuel cells or metal-air batteries

  17. Saturated Domino Coverings

    CERN Document Server

    Buchanan, Andrew; Ryba, Alex

    2011-01-01

    A domino covering of a board is saturated if no domino is redundant. We introduce the concept of a fragment tiling and show that a minimal fragment tiling always corresponds to a maximal saturated domino covering. The size of a minimal fragment tiling is the domination number of the board. We define a class of regular boards and show that for these boards the domination number gives the size of a minimal X-pentomino covering. Natural sequences that count maximal saturated domino coverings of square and rectangular boards are obtained. These include the new sequences A193764, A193765, A193766, A193767, and A193768 of OEIS.

  18. The value of brain blood perfusion SPECT imaging in evaluation of the curative effect of hyperbaric oxygen in patients with ischemic brain injury

    International Nuclear Information System (INIS)

    Objective: Brain blood flow SPECT perfusion can detect changes in brain blood flow. The obiective of this study was to explore the clinical value of SPECT perfusion imaging in brain ischemic injury due to traumatic at before and after hyperbaric oxygen (HBO)treatment.Methods: Sixty-five cases of secondary ischemic brain injury patients were randomly divided into two groups. One was with HBO treatment group and the other was with conventional treatment. All had brain perfusion SPECT at before and after treatment. Computer region of interest (ROI)technology was applied in the cross-sectional images using lo-cat mirror ratio (Ra) method to determine cerebral ischemic lesions. The t-test was used to analyze the quantitative data. It would be considered as abnormal if the brain perfusion SPECT reduce Ra ≤ 0.9 aftertreatment. Results: In HBO treatment group.regional cerebral blood flow (rCBF) before and after treatment to reduce the district Ra values were 0.58 ± 0.1l and 0.82 ± 0.12 (t=7.327, P<0.01). In con-ventional treatment group. Rcbf before and after treatment to reduce the district Ra values were 0.6l ± 0.13 and 0.73 ± 0.12 (t=2.153. P=0.038). IncreaSed Rcbf at ischemic lesions in HBO treatment group was 0.24 ± 0.08 and was 0.12 ± 0.06 for conventional treatment group (t=2.571. P=0.015). Conclusions: Brain SPECT imaging could sensitively reflect the rCBF before and after treatment and was considered to be useful for therapeutic monitoring of HBO treatment efficacy. (authors)

  19. Monitoring tissue oxygen availability with near infrared spectroscopy (NIRS) in health and disease

    DEFF Research Database (Denmark)

    Boushel, R; Langberg, Henning; Olesen, J; Gonzales-Alonzo, J; Bülow, J; Kjaer, M

    2001-01-01

    vessels (arterioles, capillaries and venules). Refinement of NIRS hardware and the algorithms used to deconvolute the light absorption signal have improved the resolution and validity of cytochrome oxidase measurements. NIRS has been applied to measure oxygenation in a variety of tissues including muscle...... along with the assessment of tissue O2 saturation. The venular O2 saturation can be estimated with NIRS by applying venous occlusion and measuring changes in oxygenated vs. total hemoglobin. These various measurements provide the opportunity to evaluate several important metabolic and circulatory......Near infrared spectroscopy (NIRS) is becoming a widely used research instrument to measure tissue oxygen (O2) status non-invasively. Continuous-wave spectrometers are the most commonly used devices, which provide semi-quantitative changes in oxygenated and deoxygenated hemoglobin in small blood...

  20. Label-free oxygen-metabolic photoacoustic microscopy in vivo

    Science.gov (United States)

    Yao, Junjie; Maslov, Konstantin I.; Zhang, Yu; Xia, Younan; Wang, Lihong V.

    2011-07-01

    Almost all diseases, especially cancer and diabetes, manifest abnormal oxygen metabolism. Accurately measuring the metabolic rate of oxygen (MRO2) can be helpful for fundamental pathophysiological studies, and even early diagnosis and treatment of disease. Current techniques either lack high resolution or rely on exogenous contrast. Here, we propose label-free metabolic photoacoustic microscopy (mPAM) with small vessel resolution to noninvasively quantify MRO2 in vivo in absolute units. mPAM is the unique modality for simultaneously imaging all five anatomical, chemical, and fluid-dynamic parameters required for such quantification: tissue volume, vessel cross-section, concentration of hemoglobin, oxygen saturation of hemoglobin, and blood flow speed. Hyperthermia, cryotherapy, melanoma, and glioblastoma were longitudinally imaged in vivo. Counterintuitively, increased MRO2 does not necessarily cause hypoxia or increase oxygen extraction. In fact, early-stage cancer was found to be hyperoxic despite hypermetabolism.

  1. Muscle oxygenation during exercise under hypoxic conditions assessed by spatially resolved broadband NIR spectroscopy

    Science.gov (United States)

    Geraskin, Dmitri; Platen, Petra; Franke, Julia; Andre, Christiane; Bloch, Wilhelm; Kohl-Bareis, Matthias

    2005-08-01

    Near-infrared spectroscopy (NIRS) is used for the non-invasive measurement of muscle oxygenation during an incremental cycle test in healthy volunteers. A broad band spatially resolved system is used that allows the reliability of current algorithms to be inspected with the main emphasis on tissue oxygen saturation (SO2) and oxygenated and deoxygenated haemoglobin concentrations. Physiological conditions were modulated by changing oxygen supply from normal (21 % O2 in inspired air) to conditions corresponding to 2000 and 4000 m altitude above sea level (15.4 and 11.9 % O2). Under these hypoxic conditions the decrease in SO2 with increased exercise power is highly correlated with the oxygen content of the inspired air. There is a clear correlation with physiological parameters (heart rate, pulse oxymetry, blood gas, lactate, spirometric data). Skin oxygenation parameters are compared to those of muscle.

  2. Evaluation of Fagara zanthoxyloides root extract in sickle cell anemia blood in vitro.

    Science.gov (United States)

    Honig, G R; Farnsworth, N R; Ferenc, C; Vida, L N

    1975-01-01

    An aqueous extract was prepared from roots of Fagara zanthoxyloides and examined for evidence of an antisickling effect in vitro. Addition of 25 mg/ml of the extract to fresh blood samples from sickle anemia subjects produced no change in the blood oxygen dissociation curves, and approximately equal percentages of sickled cells were observed at comparable oxygen saturation levels in the presence or absence of the extract. These observations fail to confirm previous reports describing an antisickling effect of root extracts of Fagara zanthoxyloides. PMID:1202311

  3. 自体血液回收联合控制性降压减少输血及对脑组织氧合和乳酸代谢的影响%Combined autologous transfusion with controlled hypotension to reduce blood transfusion and the influence on brain tissue oxygenation and lactate metabolism

    Institute of Scientific and Technical Information of China (English)

    侯南丽; 袁莉; 刘爱杰; 王世端; 武贞芝

    2014-01-01

    Objective To observe the effects of blood salvage and controlled hypotension which can reduce allogeneic blood transfusion on brain tissue oxygenation and lactic acid metabolism in patients with spinal surgery, and to determine the efficacy and safety of combination. Methods Sixty patients scheduled for spinal surgery with ASA grade I-Ⅱ levels in our hospital from December 2011 to May 2013 were randomly divided into two groups with 30 cases in each:Experimental Group (blood salvage combing controlled hypotension) or Control Group. General anesthesia was chosen in all patients. Blood samples were taken from the right jugular bulb and radial arterial simultaneously before surgery (T0), the end of surgery(T2) and 24 hours after surgery (T3) for blood gas analysis. Arterial oxygen partial pressure (PaO2), arterial oxygen saturation degree (SaO2), jugular bulb blood oxygen partial pressure (PjvO2), jugular bulb oxygen saturation (SjvO2), arterial and venous blood lactic acid (LacA, Lacjv) were recorded. Cerebral arterial oxygen content (CaO2), jugular bulb oxygen content (CjvO2), cerebral oxygen consumption C (ajv) O2 , cerebral oxygen uptake rate (CERO2) and difference in arterial and venous lactic acid content (ADVL) were calculated according to Fick formula. T1 is the stable point of intraoperative controlled hypotension. Patients' infusion volume,blood loss,autologous blood transfusion,allogeneic blood transfusion and the hemoglobin levels were recorded at each time point of these two groups. Results There was no significant difference in age, body weight, heart rate (HR), preoperative hemoglobin level (Hb) and preoperative coagulation index between two groups(P>0.05). Allogeneic blood transfusion volumes were significantly less in Experimental Group than those in Control Croup (P0.05). The CaO2, CjvO2 decreased significantly at the end of surgery(T2) and 24 hours after surgery (T3)compared with T0 (P0.05). Blood pressure was significantly lower in Control Group

  4. Reduced blood flow response to acetazolamide reflects pre-existing vasodilation and decreased oxygen metabolism in major cerebral arterial occlusive disease

    International Nuclear Information System (INIS)

    A decrease in the cerebral blood flow (CBF) response to acetazolamide may indicate an increase in cerebral blood volume (CBV) caused by reduced perfusion pressure in patients with major cerebral artery steno-occlusive lesions. However, a decrease in cerebral metabolic rate of oxygen (CMRO2) caused by ischemic changes may also decrease the CBF response to acetazolamide by decreasing the production of carbon dioxide. The purpose of this study was to determine whether the values of CBV and CMRO2 are independent predictors of the CBF response to acetazolamide in major cerebral arterial occlusive disease. We used positron emission tomography to study 30 patients with major cerebral artery steno-occlusive lesions. The CBF response to acetazolamide was assessed by measuring baseline CBF and CBF 10 min after an intravenous injection of 1 g of acetazolamide. Multivariate analysis was used to test the independent predictive value of the CBV and CMRO2 at baseline with respect to the percent change in CBF during acetazolamide administration. Both increased CBV and decreased CMRO2 were significant and independent predictors of the reduced CBF response to acetazolamide. CBV accounted for 25% of the variance in the absolute change in CBF during acetazolamide administration and 42% of the variance in the percent change in CBF, whereas CMRO2 accounted for 19% and 4% of the variance, respectively. In patients with major cerebral arterial occlusive disease, a decrease in CMRO2 may contribute to the reduced CBF response to acetazolamide, although an increase in CBV appears to be the major contributing factor. (orig.)

  5. Acute ascorbic acid ingestion increases skeletal muscle blood flow and oxygen consumption via local vasodilation during graded handgrip exercise in older adults.

    Science.gov (United States)

    Richards, Jennifer C; Crecelius, Anne R; Larson, Dennis G; Dinenno, Frank A

    2015-07-15

    Human aging is associated with reduced skeletal muscle perfusion during exercise, which may be a result of impaired endothelium-dependent dilation and/or attenuated ability to blunt sympathetically mediated vasoconstriction. Intra-arterial infusion of ascorbic acid (AA) increases nitric oxide-mediated vasodilation and forearm blood flow (FBF) during handgrip exercise in older adults, yet it remains unknown whether an acute oral dose can similarly improve FBF or enhance the ability to blunt sympathetic vasoconstriction during exercise. We hypothesized that 1) acute oral AA would improve FBF (Doppler ultrasound) and oxygen consumption (V̇o2) via local vasodilation during graded rhythmic handgrip exercise in older adults (protocol 1), and 2) AA ingestion would not enhance sympatholysis in older adults during handgrip exercise (protocol 2). In protocol 1 (n = 8; 65 ± 3 yr), AA did not influence FBF or V̇o2 during rest or 5% maximal voluntary contraction (MVC) exercise, but increased FBF (199 ± 13 vs. 248 ± 16 ml/min and 343 ± 24 vs. 403 ± 33 ml/min; P forearm vascular conductance (FVC). In protocol 2 (n = 10; 63 ± 2 yr), following AA, FBF was similarly elevated during 15% MVC (∼ 20%); however, vasoconstriction to reflex increases in sympathetic activity during -40 mmHg lower-body negative pressure at rest (ΔFVC: -16 ± 3 vs. -16 ± 2%) or during 15% MVC (ΔFVC: -12 ± 2 vs. -11 ± 4%) was unchanged. Our collective results indicate that acute oral ingestion of AA improves muscle blood flow and V̇o2 during exercise in older adults via local vasodilation. PMID:25980023

  6. THE DETERMINATION OF CORRELATION LINKAGES BETWEEN LEVEL OF REACTIVE OXYGEN SPECIES, CONTENTS OF NEUTROPHILES AND BLOOD GAS COMPOSITION IN EXPERIMENTAL ACUTE LUNG INJURY.

    Science.gov (United States)

    Marushchak, M; Krynytska, I; Petrenko, N; Klishch, I

    2016-04-01

    Acute lung injury (ALI) remains a major cause of acute respiratory failure and death of patients. Despite the achievements at the current stage in treatment, morbidity and mortality of ALI remain high. However, a deeper understanding of the pathogenetic links of ALI, identifying of the predictors that positively or negatively influence on the course of the syndrome, the correlation between some pathogenetic mechanisms will improve therapeutic strategies for patients with ALI, which makes the actuality of this study. The aim of the research was to detect additional pathogenetic mechanisms of the acute lung injury development in rats based on a comparative analysis of the correlations between the level of reactive oxygen species in blood and bronchoalveolar lavage, contents of neutrophils and blood gas composition. The experiments were performed on 54 white nonlinear mature male rats 200-220g in weight. The animals were divided into 5 groups: the 1st - control group (n=6), the 2nd - animals affected by hydrochloric acid for 2 hours (n=12), the 3rd - animals affected by hydrochloric acid for 6 hours (n=12), the 4th - animals affected by hydrochloric acid for 12 hours (n=12), the 5th - animals affected by hydrochloric acid for 24 hours (n=12). Correlation analysis was performed between all the studied indices. Coefficient of linear correlation (r) and its fidelity (p) was calculated that was accordingly denoted in the tables (correlation matrices). The correlation coefficient was significant at palveoli. On this background non-specific inflammatory reaction is developed at lung microvessels level with violation of lung homeostasis, which is iniciated by neutrophils' activation, which are producing ROS. PMID:27249444

  7. A Novel β-Globin Chain Hemoglobin Variant, Hb Allentown [β137(H15)Val→Trp (GTG>TGG) HBB: c.412_413delinsTG, p.Val138Trp], Associated with Low Oxygen Saturation, Intermittent Aplastic Crises and Splenomegaly.

    Science.gov (United States)

    Collier, Anderson B; Coon, Lea M; Monteleone, Philip; Umaru, Samuel; Swanson, Kenneth C; Hoyer, James D; Oliveira, Jennifer L

    2016-03-01

    Hemoglobin (Hb) variants may be associated with low oxygen saturation and exacerbated episodes of anemia from common stressors such as viral infections. These attributes frequently cause increased clinical concern and unnecessary and expensive testing if not considered early in the evaluation of the patient. Some clinically significant Hb variants result in a normal Hb electrophoresis result, which can be method-dependent. Herein we describe a patient with low oxygen saturation and a history of hemolytic anemia who was subsequently found to carry a novel, unstable β-globin variant that we have named Hb Allentown [β137(H15)Val→Trp (GTG>TGG) HBB: c.412_413delinsTG, p.Val138Trp] for the place of identification of the variant. Hb Allentown is formed by a rare double nucleotide substitution within the same codon. Additionally, positive identification of rare Hb variants characterized by a single method is discouraged, as the Hb variant was misclassified as Hb S-South End or β6(A3)Glu→Val;β132(H10)Lys→Asn (HBB: c.[20A > T;399A > C]) by the initial laboratory. PMID:26681102

  8. Blood and Lymph Diseases

    Science.gov (United States)

    ... in direct contact with the external environment, the circulatory system acts as a transport system for these cells. Two distinct fluids move through the circulatory system: blood and lymph. Blood carries oxygen and nutrients ...

  9. Tissue oxygenation and muscular substrate turnover in two subjects with high hemoglobin oxygen affinity.

    OpenAIRE

    Wranne, B; Berlin, G; Jorfeldt, L; Lund, N.

    1983-01-01

    Oxygen transport to and substrate turnover in leg muscle were studied at rest and during light and heavy upright bicycle exercise in two brothers with a hereditary hemoglobinopathy associated with high oxygen affinity (P50 = 13 mmHg). Femoral venous oxygen tension was below normal and femoral venous oxygen saturation above normal at rest and during exercise. Thus, the arterial-femoral venous oxygen saturation difference was decreased. Despite a compensatory increase in hemoglobin concentratio...

  10. Prognostic Significance of Transverse Relaxation Rate (R2*) in Blood Oxygenation Level-Dependent Magnetic Resonance Imaging in Patients with Invasive Breast Cancer

    Science.gov (United States)

    Choi, Hye Young; Ko, Eun Sook; Han, Boo-Kyung; Kim, Eun Ju; Kim, Sun Mi; Lim, Yaeji; Kim, Rock Bum

    2016-01-01

    Objective To examine the relationship between magnetic resonance transverse relaxation rate (R2*) and prognostic factors. Materials and Methods A total of 159 women with invasive ductal carcinomas (IDCs) underwent breast magnetic resonance imaging (MRI) including blood oxygenation level-dependent (BOLD) sequence at 3 T. The distribution of the measured R2* values were analyzed, and the correlation between R2* and various prognostic factors (age, tumor size, histologic grade, lymphovascular invasion, and axillary lymph node status, as well as expression of estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, p53, and Ki-67) were retrospectively assessed using patient medical records. Results The baseline R2* values of the IDCs were very heterogeneous with wide range among the patients. The mean R2* value was (32.8 ± 14.0) Hz with a median of 29.3 Hz (range 13.5–109.4 Hz). In multivariate analysis, older age was associated with decreased R2* value (P = 0.011) and IDCs with p53-overexpression showed higher R2* values than those without p53-overexpression group (P = 0.031). Other prognostic factors were not significantly correlated with R2* value. Conclusion In this study, R2* values were significantly correlated with age and expression of p53. Further studies are necessary to determine the prognostic value of BOLD-MRI. PMID:27384310

  11. Regional cerebral blood flow and oxygen metabolism in patients with ischemic stroke studied with high resolution pet and the O-15 labelled gas steady-state method

    International Nuclear Information System (INIS)

    Although regional cerebral blood flow (rCBF) studies have considerably increased pathophysiological knowledge in ischemic cerebrovascular disease, sometimes the results of such studies do not correlate with neurological abnormalities observed in the subjects being examined. Because regional neuronal activities always couple to the regional energy metabolism of brain tissue, simultaneous observation of rCBF and regional energy metabolism, such as regional oxygen consumption (rCMRO/sub 2/) and regional glucose consumption (rCMRG1), will provide greater understanding of the pathophysiology of the disease than rCBF study alone. Positron emission tomography (PET) using the 0-15 labelled gas steady-state method offers simultaneous measurement of rCBF and rCMRO/sub 2/ in vivo, and demonstrates imbalance between rCBF and rCMRO/sub 2/ in an ischemic lesion in a human brain. However, clinical PET studies in ischemic cerebrovascular disease reported previously, have been carried out using low resolution (more than 15 mm in the full width at half maximum; FWHM) PET. This report presents preliminary results using a high resolution tomograph; Headtome III and 0-15 labelled gas steady state method to investigate ischemic cerebrovascular disease

  12. Blood oxygenation level-dependent MR imaging as a predictor of therapeutic response to concurrent chemoradiotherapy in cervical cancer: a preliminary experience

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chan Kyo; Park, Sung Yoon; Park, Byung Kwan [Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Samsung Medical Center, Seoul (Korea, Republic of); Park, Won; Huh, Seung Jae [Sungkyunkwan University School of Medicine, Department of Radiation Oncology, Samsung Medical Center, Seoul (Korea, Republic of)

    2014-07-15

    To investigate the value of blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) as a predictor of therapeutic response in cervical cancer patients undergoing concurrent chemoradiotherapy (CCRT). Thirty consecutive patients with biopsy-proven cervical cancer were examined by BOLD MRI before (preTx) and after CCRT (postTx). The R2* value (s{sup -1}) was calculated in the tumour and normal myometrium for preTx and postTx studies. Final tumour responses, as determined by changes of tumour size or volume on MRI, were correlated with tumour R2* values at preTx. The mean R2* values of tumours at preTx (21.1) were significantly lower than those at postTx (39.4 s{sup -1}) (p < 0.001), while those of normal myometrium were similar between preTx and postTx (p = 0.363). At preTx, tumour R2* values showed significantly negative correlation with final tumour size response (p = 0.022, Spearman's coefficient = -0.415). However, tumour R2* values at preTx were not associated with final tumour volume response (p = 0.069). BOLD MRI at 3 T, as an imaging biomarker, may have the potential to evaluate therapeutic response in cervical cancers. The association between BOLD MRI findings and CCRT responses warrants further validation. (orig.)

  13. Regional placental blood oxygen level dependent (BOLD) changes with gestational age in normally developing pregnancies using long duration R2* mapping in utero

    Science.gov (United States)

    Dighe, Manjiri; Kim, Yun Jung; Seshamani, Sharmishtaa; Blazejewska, Ania I.; Mckown, Susan; Caucutt, Jason; Gatenby, Christopher; Studholme, Colin

    2016-03-01

    The aim of this study was to examine the use of R2* mapping in maternal and fetal sub-regions of the placenta with the aim of providing a reference for blood oxygenation levels during normative development. There have been a number of MR relaxation studies of placental tissues in-utero, but none have reported R2* value changes with age, or examined differences in sub-regions of the placenta. Here specialized long-duration Multi-frame R2* imaging was used to create a stable estimate for R2* values in different placental regions in healthy pregnant volunteers not imaged for clinical reasons. 27 subjects were recruited and scanned up to 3 times during their pregnancy. A multi-slice dual echo EPI based BOLD acquisition was employed and repeated between 90 and 150 times over 3 to 5 minutes to provide a high accuracy estimate of the R2* signal level. Acquisitions were also repeated in 13 cases within a visit to evaluate reproducibility of the method in a given subject. Experimental results showed R2* measurements were highly repeatable within a visit with standard deviation of (0.76). Plots of all visits against gestational age indicated clear correlations showing decreases in R2* with age. This increase was consistent was also consistent over time in multiple visits of the same volunteer during their pregnancy. Maternal and fetal regional changes with gestational age followed the same trend with increase in R2* over the gestational age.

  14. MO-G-BRF-06: Radiotherapy and Prompt Oxygen Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Kissick, M; Campos, D; Adamson, E; Niles, D; Torres, A; L, Che Fru; Kimple, R; Fain, S; Kogel, A van der [University of Wisconsin - Madison, Madison, WI (United States); Jacques, S [Oregon Health ' Science University, Portland, OR (United States)

    2014-06-15

    Purpose: Adaptive radiotherapy requires a knowledge of the changing local tumor oxygen concentrations for times on the order of the treatment time, a time scale far shorter than cell death and proliferation. This knowledge will be needed to guide hypofractionated radiotherapy. Methods: A diffuse optical probe system was developed to spatially average over the whole interior of athymic Sprague Dawley nude mouse xenografts of human head and neck cancers. The blood volume and hemoglobin saturation was measured in real time. The quantities were measured with spectral fitting before and after 10 Gy of radiation is applied. An MRI BOLD scan is acquired before and after 10 Gy that measures regional changes in R2* which is inversely proportional to oxygen availability. Simulations were performed to fit the blood oxygen dynamics and infer changes in hypoxia within the tumor. Results: The optical probe measured nearly constant blood volume and a significant drop in hemoglobin saturation of about 30% after 10 Gy over the time scale of less than 30 minutes. The averaged R2* within the tumor volume increased by 15% after the 10 Gy dose, which is consistent with the optical results. The simulations and experiments support likely dynamic metabolic changes and/or fast vasoconstrictive signals are occurring that change the oxygen concentrations significantly, but not cell death or proliferation. Conclusion: Significant oxygen changes were observed to occur within 30 minutes, coinciding with the treatment time scale. This dynamic is very important for patient specific adaptive therapy. For hypofractionated therapy, the local instantaneous oxygen content is likely the most important variable to control. The invention of a bedside device for the purpose of measuring the instantaneous response to large radiation doses would be an important step to future improvements in outcome.

  15. MO-G-BRF-06: Radiotherapy and Prompt Oxygen Dynamics

    International Nuclear Information System (INIS)

    Purpose: Adaptive radiotherapy requires a knowledge of the changing local tumor oxygen concentrations for times on the order of the treatment time, a time scale far shorter than cell death and proliferation. This knowledge will be needed to guide hypofractionated radiotherapy. Methods: A diffuse optical probe system was developed to spatially average over the whole interior of athymic Sprague Dawley nude mouse xenografts of human head and neck cancers. The blood volume and hemoglobin saturation was measured in real time. The quantities were measured with spectral fitting before and after 10 Gy of radiation is applied. An MRI BOLD scan is acquired before and after 10 Gy that measures regional changes in R2* which is inversely proportional to oxygen availability. Simulations were performed to fit the blood oxygen dynamics and infer changes in hypoxia within the tumor. Results: The optical probe measured nearly constant blood volume and a significant drop in hemoglobin saturation of about 30% after 10 Gy over the time scale of less than 30 minutes. The averaged R2* within the tumor volume increased by 15% after the 10 Gy dose, which is consistent with the optical results. The simulations and experiments support likely dynamic metabolic changes and/or fast vasoconstrictive signals are occurring that change the oxygen concentrations significantly, but not cell death or proliferation. Conclusion: Significant oxygen changes were observed to occur within 30 minutes, coinciding with the treatment time scale. This dynamic is very important for patient specific adaptive therapy. For hypofractionated therapy, the local instantaneous oxygen content is likely the most important variable to control. The invention of a bedside device for the purpose of measuring the instantaneous response to large radiation doses would be an important step to future improvements in outcome

  16. Changes in blood gas transport of altitude native soccer players near sea-level and sea-level native soccer players at altitude (ISA3600)

    OpenAIRE

    Wachsmuth, Nadine; Kley, Marlen; Spielvogel, Hilde; Aughey, Robert J; Gore, Christopher J; Bourdon, Pitre C.; Hammond, Kristal; Sargent, Charli; Roach, Gregory D.; Sanchez, Rudy Soria; Claros, Jesus C Jimenez; Schmidt, Walter F; Garvican-Lewis, Laura A

    2013-01-01

    Objectives The optimal strategy for soccer teams playing at altitude is not known, that is, ‘fly-in, fly-out’ versus short-term acclimatisation. Here, we document changes in blood gas and vascular volumes of sea-level (Australian, n=20) and altitude (Bolivian, n=19) native soccer players at 3600 m. Methods Haemoglobin-oxygen saturation (Hb-sO2), arterial oxygen content (CaO2), haemoglobin mass (Hbmass), blood volume (BV) and blood gas concentrations were measured before descent (Bolivians onl...

  17. Comparison of a New Miniaturized Extracorporeal Membrane Oxygenation System With Integrated Rotary Blood Pump to a Standard System in a Porcine Model of Acute Lung Injury.

    Science.gov (United States)

    Pilarczyk, Kevin; Heckmann, Jens; Lyskawa, Kathrin; Strauß, Andreas; Haake, Nils; Wiese, Ingo; Jakob, Heinz; Kamler, Markus; Pizanis, Nikolaus

    2016-07-01

    Extracorporeal membrane oxygenation (ECMO) is used for severe acute respiratory distress syndrome. However, available ECMO systems are large and not well designed for fast delivery, emergency implantation, and interhospital transfer. Therefore, a new miniaturized oxygenator with integrated rotary blood pump (ILIAS) was developed and compared with a standard ECMO system in a large animal model. Acute lung injury was induced with repeated pulmonary saline lavage in 14 pigs until PaO2 /FiO2 -ratio was <100 mm Hg with a positive-end-expiratory-pressure of 5 mbar. Pigs were assigned to the following three groups: group 1 (n = 4): control group with conventional ventilation; group 2 (n = 5): standard vv-ECMO; group 3 (n = 5): vv-ILIAS. Gas exchange, hemodynamics, hemolysis, and coagulation activation were examined over a period of 8 h. No device failed during the observation period. PaCO2 decreased from 59.40 ± 4.14 mm Hg to 48.62 ± 4.50 mm Hg after 1 h in the ILIAS group compared with an improvement of PaCO2 from 48.86 ± 7.45 to 40.10 ± 6.02 in the conventional ECMO group (P = not significant [n.s.]). ARDS-induced respiratory acidosis was controlled promptly with a pH of 7.2 ± 0.1 at baseline increasing to 7.4 ± 0.1 in both study groups after 60 min of ECMO support. Mean carbon dioxide transfer was comparable between the conventional ECMO and ILIAS (211.36 ± 78.39 mL/min vs. 219.99 ± 76.72 mL/min, P = n.s.). PaO2 /FiO2 increased from 118.4 ± 15.5 mm Hg to 179.1 ± 72.4 mm Hg in the ILIAS group compared with an improvement of oxygenation from 107.1 ± 24.9 mm Hg to 179.0 ± 45.7 mm Hg in the standard ECMO group (P = n.s.). Mean oxygen transfer was calculated with 136.09 ± 30.25 mL/min for the ILIAS and 129.05 ± 36.28 mL/min for the standard ECMO. Hemodynamic instability or significant activation of the plasmatic coagulation was not

  18. Arterial and venous oxygen partial pressure and utilization factor η, resp., and 133Xe muscle clearance after UV irradiation of skin or blood of healthy persons and patients with occlusive arterial disease and psoriasis, resp

    International Nuclear Information System (INIS)

    In three teams of test persons series of UV irradiations of the skin (λmax 365 nm) and of the blood (λmax 254 nm) were performed, and moreover pseudoirradiations of the blood as placebo and infrared irradiations of the skin were carried out. UV irradiations of the blood increased the factor η (O2 utilization) in all test persons. In healthy persons and patients with psoriasis UV irradiations of the skin involved a homogeneous, but less distinct effect, this was, however, not the case in patients with vascular diseases. According to the results of the 133Xe muscle clearance the improved utilization of oxygen does not result from increased peripheral blood supply. (author)

  19. Pulsatile blood flow in human bone assessed by laser-Doppler flowmetry and the interpretation of photoplethysmographic signals

    International Nuclear Information System (INIS)

    Human bone blood flow, mean blood speed and the number of moving red blood cells were assessed (in arbitrary units), as a function of time, during one cardiac cycle. The measurements were obtained non-invasively on five volunteers by laser-Doppler flowmetry at large interoptode spacing. The investigated bones included: patella, clavicle, tibial diaphysis and tibial malleolus. As hypothesized, we found that in all bones the number of moving cells remains constant during cardiac cycles. Therefore, we concluded that the pulsatile nature of blood flow must be completely determined by the mean blood speed and not by changes in blood volume (vessels dilation). Based on these results, it is finally demonstrated using a mathematical model (derived from the radiative transport theory) that photoplethysmographic (PPG) pulsations observed by others in the literature, cannot be generated by oscillations in blood oxygen saturation, which is physiologically linked to blood speed. In fact, possible oxygen saturation changes during pulsations decrease the amplitude of PPG pulsations due to specific features of the PPG light source. It is shown that a variation in blood oxygen saturation of 3% may induce a negative change of ∼1% in the PPG signal. It is concluded that PPG pulsations are determined by periodic ‘positive’ changes of the reduced scattering coefficient of the tissue and/or the absorption coefficient at constant blood volume. No explicit experimental PPG measurements have been performed. As a by-product of this study, an estimation of the arterial pulse wave velocity obtained from the analysis of the blood flow pulsations give a value of 7.8 m s−1 (95% confidence interval of the sample mean distribution: [6.7, 9.5] m s−1), which is perfectly compatible with data in the literature. We hope that this note will contribute to a better understanding of PPG signals and to further develop the domain of the vascular physiology of human bone. (note)

  20. A role for haemolymph oxygen capacity in heat tolerance of eurythermal crabs.

    Directory of Open Access Journals (Sweden)

    FolcoGiomi

    2013-05-01

    Full Text Available Heat tolerance in aquatic ectotherms is constrained by a mismatch, occurring at high temperatures, between oxygen delivery and demand which compromises the maintenance of aerobic scope. The present study analyses how the wide thermal tolerance range of an eurythermal model species, the green crab Carcinus maenas is supported and limited by its ability to sustain efficient oxygen transport to tissues. Similar to other eurytherms, C. maenas sustains naturally occurring acute warming events through the integrated response of circulatory and respiratory systems. The response of C. maenas to warming is characterized by two phases. During initial warming, oxygen consumption and heart rate increase while stroke volume and haemolymph oxygen partial pressures decrease. During further warming, dissolved oxygen levels in the venous compartment decrease below the threshold of full haemocyanin oxygen saturation. The progressive release of haemocyanin bound oxygen with further warming follows an exponential pattern, thereby saving energy in oxygen transport and causing an associated leveling off of metabolic rate. According to the concept of oxygen and capacity limited thermal tolerance, this indicates that the thermal tolerance window is widened by the increasing contribution of haemocyanin oxygen transport and associated energy savings in cardiocirculation. Haemocyanin bound oxygen sustains cardiac performance to cover the temperature range experienced by C. maenas in the field. To our knowledge this is the first study providing evidence of a relationship between thermal tolerance and blood (haemolymph oxygen transport in eurythermal invertebrates.