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Sample records for blood oxygen saturation

  1. Brain oxygen saturation assessment in neonates using T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy

    DEFF Research Database (Denmark)

    Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra Ma

    2017-01-01

    saturation in the sagittal sinus (R(2 )= 0.49, p = 0.023), but no significant correlations could be demonstrated with frontal and whole brain cerebral blood flow. These results suggest that measuring oxygen saturation by T2-prepared blood imaging of oxygen saturation is feasible, even in neonates. Strong...... sinus. A strong linear relation was found between the oxygen saturation measured by magnetic resonance imaging and the oxygen saturation measured by near-infrared spectroscopy (R(2 )= 0.64, p ..., and magnetic resonance imaging measures of frontal cerebral blood flow, whole brain cerebral blood flow and venous oxygen saturation in the sagittal sinus (R(2 )= 0.71, 0.50, 0.65; p 

  2. Blood oxygen saturation determined by transmission spectrophotometry of hemolyzed blood samples

    Science.gov (United States)

    Malik, W. M.

    1967-01-01

    Use of the Lambert-Beer Transmission Law determines blood oxygen saturation of hemolyzed blood samples. This simplified method is based on the difference in optical absorption properties of hemoglobin and oxyhemoglobin.

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

    International Nuclear Information System (INIS)

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

    2007-01-01

    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 (SpO 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 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 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. Both pulse

  4. 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

  5. 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

  6. The Choroidal Eye Oximeter - An instrument for measuring oxygen saturation of choroidal blood in vivo

    Science.gov (United States)

    Laing, R. A.; Danisch, L. A.; Young, L. R.

    1975-01-01

    The Choroidal Eye Oximeter is an electro-optical instrument that noninvasively measures the oxygen saturation of choroidal blood in the back of the human eye by a spectrophotometric method. Since choroidal blood is characteristic of blood which is supplied to the brain, the Choroidal Eye Oximeter can be used to monitor the amount of oxygen which is supplied to the brain under varying external conditions. The instrument consists of two basic systems: the optical system and the electronic system. The optical system produces a suitable bi-chromatic beam of light, reflects this beam from the fundus of the subject's eye, and onto a low-noise photodetector. The electronic system amplifies the weak composite signal from the photodetector, computes the average oxygen saturation from the area of the fundus that was sampled, and displays the value of the computed oxygen saturation on a panel meter.

  7. Cerebral tissue oxygen saturation and extraction in preterm infants before and after blood transfusion

    NARCIS (Netherlands)

    van Hoften, Jacorina C. R.; Verhagen, Elise A.; Keating, Paul; ter Horst, Hendrik J.; Bos, Arend F.

    Objective Preterm infants often need red blood cell (RBC) transfusions. The aim of this study was to determine whether haemoglobin levels before transfusion were associated with regional cerebral tissue oxygen saturation (r(c)SO(2)) and fractional tissue oxygen extraction (FTOE) and whether RBC

  8. Photoacoustic measurements of red blood cell oxygen saturation in blood bags in situ

    Science.gov (United States)

    Pinto, Ruben N.; Bagga, Karan; Douplik, Alexandre; Acker, Jason P.; Kolios, Michael C.

    2017-03-01

    Red blood cell (RBC) transfusion is a critical component of the health care services. RBCs are stored in blood bags in hypothermic temperatures for a maximum of 6 weeks post donation. During this in vitro storage period, RBCs have been documented to undergo changes in structure and function due to mechanical and biochemical stress. Currently, there are no assessment methods that monitor the quality of RBCs within blood bags stored for transfusion. Conventional assessment methods require the extraction of samples, consequently voiding the sterility of the blood bags and potentially rendering them unfit for transfusions. It is hypothesized that photoacoustic (PA) technology can provide a rapid and non-invasive indication of RBC quality. In this study, a novel PA setup was developed for the acquisition of oxygen saturation (SO2) of two blood bags in situ. These measurements were taken throughout the lifespan of the blood bags (42 days) and compared against the clinical gold standard method of the blood gas analyzer (BGA). SO2 values of the blood bags increased monotonically throughout the storage period. A strong correlation between PA SO2 and BGA SO2 was found, however, PA values were on average 3.5% lower. Both techniques found the bags to increase by an SO2 of approximately 20%, and measured very similar rates of SO2 change. Future work will be focused on determining the cause of discrepancy between SO2 values acquired from PA versus BGA, as well as establishing links between the measured SO2 increase and other changes in RBC in situ.

  9. Systematic instrumental errors between oxygen saturation analysers in fetal blood during deep hypoxemia.

    Science.gov (United States)

    Porath, M; Sinha, P; Dudenhausen, J W; Luttkus, A K

    2001-05-01

    During a study of artificially produced deep hypoxemia in fetal cord blood, systematic errors of three different oxygen saturation analysers were evaluated against a reference CO oximeter. The oxygen tensions (PO2) of 83 pre-heparinized fetal blood samples from umbilical veins were reduced by tonometry to 1.3 kPa (10 mm Hg) and 2.7 kPa (20 mm Hg). The oxygen saturation (SO2) was determined (n=1328) on a reference CO oximeter (ABL625, Radiometer Copenhagen) and on three tested instruments (two CO oximeters: Chiron865, Bayer Diagnostics; ABL700, Radiometer Copenhagen, and a portable blood gas analyser, i-STAT, Abbott). The CO oximeters measure the oxyhemoglobin and the reduced hemoglobin fractions by absorption spectrophotometry. The i-STAT system calculates the oxygen saturation from the measured pH, PO2, and PCO2. The measurements were performed in duplicate. Statistical evaluation focused on the differences between duplicate measurements and on systematic instrumental errors in oxygen saturation analysis compared to the reference CO oximeter. After tonometry, the median saturation dropped to 32.9% at a PO2=2.7 kPa (20 mm Hg), defined as saturation range 1, and to 10% SO2 at a PO2=1.3 kPa (10 mm Hg), defined as range 2. With decreasing SO2, all devices showed an increased difference between duplicate measurements. ABL625 and ABL700 showed the closest agreement between instruments (0.25% SO2 bias at saturation range 1 and -0.33% SO2 bias at saturation range 2). Chiron865 indicated higher saturation values than ABL 625 (3.07% SO2 bias at saturation range 1 and 2.28% SO2 bias at saturation range 2). Calculated saturation values (i-STAT) were more than 30% lower than the measured values of ABL625. The disagreement among CO oximeters was small but increasing under deep hypoxemia. Calculation found unacceptably low saturation.

  10. Misconceptions in Reporting Oxygen Saturation

    NARCIS (Netherlands)

    Toffaletti, John; Zijlstra, Willem G.

    2007-01-01

    BACKGROUND: We describe some misconceptions that have become common practice in reporting blood gas and cooximetry results. In 1980, oxygen saturation was incorrectly redefined in a report of a new instrument for analysis of hemoglobin (Hb) derivatives. Oxygen saturation (sO(2)) was redefined as the

  11. The effect of sensory stimulation provided by family on arterial blood oxygen saturation in critical care patients.

    Science.gov (United States)

    Yousefi, Hojatollah; Naderi, Mojgan; Daryabeigi, Reza

    2015-01-01

    Stressors in the intensive care unit (ICU) impair patients' comfort, excite the stress response, and increase oxygen consumption in their body. Non-medical interventions are recommended by several studies as a treatment to improve comfort in the ICU patients. Sensory stimulation is one of the most important interventions. Since arterial blood oxygen saturation is an important index of patients' clinical and respiratory condition, this study aimed to investigate the effect of sensory stimulation provided by family on arterial blood oxygen saturation in critical care patients. This study is a clinical trial conducted on 64 patients hospitalized in the ICU wards of Al-Zahra and Kashani hospitals in Isfahan, Iran in 2012 and 2013. The patients were selected by simple sampling method and were randomly assigned to two groups (study and control). Patients' arterial blood oxygen saturations were measured 10 min before, immediately after, 10 min and 30 min after sensory stimulation in the study group, and simultaneously in the control group without any intervention. Repeated measures analysis of variance (ANOVA) showed a significant difference in the mean of arterial blood oxygen saturation levels 10 min before, immediately after, 10 min and 30 min after sensory stimulation in the study group (P 0.18). Application of sensory stimulations as a nursing and non-medical intervention by the family members improves comfort and increases the level of blood oxygen saturation in critical care patients.

  12. High-affinity hemoglobin and blood oxygen saturation in diving emperor penguins.

    Science.gov (United States)

    Meir, Jessica U; Ponganis, Paul J

    2009-10-01

    The emperor penguin (Aptenodytes forsteri) thrives in the Antarctic underwater environment, diving to depths greater than 500 m and for durations longer than 23 min. To examine mechanisms underlying the exceptional diving ability of this species and further describe blood oxygen (O2) transport and depletion while diving, we characterized the O2-hemoglobin (Hb) dissociation curve of the emperor penguin in whole blood. This allowed us to (1) investigate the biochemical adaptation of Hb in this species, and (2) address blood O2 depletion during diving, by applying the dissociation curve to previously collected partial pressure of O2 (PO2) profiles to estimate in vivo Hb saturation (SO2) changes during dives. This investigation revealed enhanced Hb-O2 affinity (P50=28 mmHg, pH 7.5) in the emperor penguin, similar to high-altitude birds and other penguin species. This allows for increased O2 at low blood PO2 levels during diving and more complete depletion of the respiratory O2 store. SO2 profiles during diving demonstrated that arterial SO2 levels are maintained near 100% throughout much of the dive, not decreasing significantly until the final ascent phase. End-of-dive venous SO2 values were widely distributed and optimization of the venous blood O2 store resulted from arterialization and near complete depletion of venous blood O2 during longer dives. The estimated contribution of the blood O2 store to diving metabolic rate was low and highly variable. This pattern is due, in part, to the influx of O2 from the lungs into the blood during diving, and variable rates of tissue O2 uptake.

  13. Evaluation of Nd:YAG laser on partial oxygen saturation of pulpal blood in anterior hypersensitive teeth.

    Science.gov (United States)

    Birang, Reza; Kaviani, Naser; Mohammadpour, Mehdi; Abed, Ahmad Moghareh; Gutknecht, Norbert; Mir, Maziar

    2008-07-01

    Dentine hypersensitivity has of long been known to be a common clinical problem in dental practices. Lasers have recently come to play a prominent role in the treatment of this disorder. They might, however, cause dental pulp damage. This study was conducted to evaluate the effect of Nd:yttrium-aluminum-garnet (YAG) laser on partial oxygen saturation of pulpal blood in sensitive anterior teeth. In this clinical trial, 65 hypersensitive teeth were selected and randomly allocated to two groups. The study group involved Nd:YAG laser treatment, while no treatment was employed for the control group. Using a pulse oximetry system, evaluations were preformed of the partial oxygen saturation in the pulpal blood before, immediately after, 1 week after, and 1 month after the treatment. The results were analyzed using the SPSS software and repeated-measures analysis of variance and paired-samples t tests. The mean partial oxygen saturation of the blood was found to be 85.4% in the study group, which was not significantly different from that of the control group. No significant differences were observed in the control group between the means obtained from pretreatment and post-treatment intervals (P > 0.05). The Post-treatment partial oxygen saturation mean rose to 89.3% (P = 0.001) and remained constant throughout the following week after it. However, no significant differences were found between the pretreatment partial oxygen saturation mean and the same measurement 1 month after treatment (P = 0.702). Nd:YAG laser therapy for dentine desensitization of anterior teeth caused no persistent changes in the partial oxygen saturation of pulpal blood. It may, therefore, be concluded that the diffusion of heat induced by the Nd:YAG laser into the pulp within the limit of the desensitization parameters cause no irreversible damages in the dental pulp.

  14. Intra-dialytic blood oxygen saturation (SO2): association with dialysis hypotension (the SOGLIA Study).

    Science.gov (United States)

    Mancini, E; Perazzini, C; Gesualdo, L; Aucella, F; Limido, A; Scolari, F; Savoldi, S; Tramonti, M; Corazza, L; Atti, M; Severi, S; Bolasco, P; Santoro, A

    2017-12-01

    Intradialytic hypotension (IDH) has a dramatic impact on the main outcomes of dialysis patients. Early warning of hemodynamic worsening during dialysis would enable preventive measures to be taken. Blood oxygen saturation (SO 2 ) is used for hemodynamic monitoring in the critical care setting and may provide useful information about IDH onset. To evaluate whether short- and medium-term variations in the SO 2 signal (ST-SO 2var , MT-SO 2var ,) during dialysis are a predictor of IDH. In this 3-month observational cohort study, 51 hypotension-prone chronic hemodialysis (HD) patients, with vascular access by arteriovenous fistula (AVF) or central venous catheter (CVC), were enrolled. Continuous non-invasive blood SO 2 was monitored (fc = 0.2 Hz) by an optical sensor on the arterial line of the extracorporeal circulation; blood pressure (every 30 min), symptoms and their time of appearance were noted. Predictive power of IDH was expressed by the area under curve (AUC) sensitivity and specificity based on intradialytic variations in SO 2 . A total of 1290 HD sessions were analyzed. Overall, off-line ST-SO 2var analysis proved able to correctly predict IDH in 67 % of the sessions where IDH occurred. The best predictive performance was found in the presence of highly arterialized AVF (SO 2  > 95 %) (75 % sensitivity; AUC 0.825; p < 0.05). On the contrary, in sessions with CVC, IDH prediction proved more efficient by MT-SO 2var (AUC 0.575; p = 0.01). Intradialytic SO 2 variability could be a valid parameter to detect in advance the hemodynamic worsening that precedes IDH. Appropriate timely intervention could help prevent IDH onset.

  15. Dual-wavelength photothermal optical coherence tomography for blood oxygen saturation measurement

    Science.gov (United States)

    Yin, Biwei; Kuranov, Roman V.; McElroy, Austin B.; Milner, Thomas E.

    2013-03-01

    We report design and demonstration of a dual wavelength photothermal (DWP) optical coherence tomography (OCT) system for imaging of a phantom microvessel and measurement of hemoglobin oxygen saturation (SO2) level. The DWP-OCT system contains a swept-source (SS) two-beam phase-sensitive (PhS) OCT system (1060 nm) and two intensity modulated photothermal excitation lasers (770 nm and 800 nm). The PhS-OCT probe beam (1060 nm) and photothermal excitation beams are combined into one single-mode optical fiber. A galvanometer based two-dimensional achromatic scanning system is designed to provide 14 μm lateral resolution for the PhS-OCT probe beam (1060 nm) and 13 μm lateral resolution for photothermal excitation beams. DWP-OCT system's sensitivity is 102 dB, axial resolution is 13 μm in tissue and uses a real-time digital dispersion compensation algorithm. Noise floor for optical pathlength measurements is 300 pm in the signal frequency range (380-400 Hz) of photothermal modulation frequencies. Blood SO2 level is calculated from measured optical pathlength (op) signal in a 300 μm diameter microvessel phantom introduced by the two photothermal excitation beams. En-face and B-scan images of a phantom microvessel are recorded, and six blood samples' SO2 levels are measured using DWP-OCT and compared with values provided by a commercial blood oximeter. A mathematical model indicates thermal diffusion introduces a systematic artifact that over-estimates SO2 values and is consistent with measured data.

  16. Investigating Functional Extension of Optical Coherence Tomography for Spectroscopic Analysis of Blood Oxygen Saturation

    Science.gov (United States)

    Chen, Siyu

    Over the past two decades, optical coherence tomography (OCT) has been successfully applied to various fields of biomedical researching and clinical studies, including cardiology, urology, dermatology, dentistry, oncology, and most successfully, ophthalmology. This dissertation seeks to extend the current OCT practice, which is still largely morphology-based, into a new dimension, functional analysis of metabolic activities in vivo. More specifically, the investigation is focused on retrieving blood oxygen saturation (sO2) using intrinsic hemoglobin optical absorption contrast. Most mammalian cells rely on aerobic respiration to support cellular function, which means they consume oxygen to create adenosine triphosphate (ATP). Metabolic rate of oxygen (MRO2), a key hemodynamic parameter, characterizes how much oxygen is consumed during a given period of time, reflecting the metabolic activity of the target tissue. For example, retinal neurons are highly active and almost entirely rely on the moment-to-moment oxygen supply from retinal circulations. Thus, variation in MRO2 reveals the instantaneous activity of these neurons, shedding light on the physiological and pathophysiological change of cellular functions. Eventually, measuring MRO2 can potentially provide a biomarker for early-stage disease diagnosis, and serve as one benchmark for evaluating effectiveness of medical intervention during disease management. Essential in calculating MRO2, blood sO2 measurements using spectroscopic OCT analysis has been attempted as early as 2003. OCT is intrinsically sensitive to the blood optical absorption spectrum due to its wide-band illumination and detection scheme relying on back-scattered photon. However, accurate retrieval of blood sO2 using conventional near infrared (NIR) OCT systems in vivo has remained challenging. It was not until the development of OCT systems using visible light illumination (vis-OCT) when accurate measurement of blood sO2 was reported in live

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

    International Nuclear Information System (INIS)

    Dunaev, A V; Palmer, S G; Stewart, N A; Sokolovski, S G; Rafailov, E U; Sidorov, V V; Krupatkin, A I; Rafailov, I E

    2014-01-01

    Multi-functional laser non-invasive diagnostic systems allow the study of a number of microcirculatory parameters, including index of blood microcirculation (I m ) (by laser Doppler flowmetry, LDF) and oxygen saturation (S t O 2 ) 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)

  18. Photoplethysmographic signals and blood oxygen saturation values during artificial hypothermia in healthy volunteers

    International Nuclear Information System (INIS)

    Shafique, M; Kyriacou, P A

    2012-01-01

    Pulse oximetry utilizes the technique of photoplethysmography to estimate arterial oxygen saturation (SpO 2 ) values. During hypothermia, the amplitude of the photoplethysmograph (PPG) is compromised which can lead to inaccurate estimation of SpO 2 . A new mutlimode PPG/pulse oximeter sensor was developed to investigate the behaviour of PPGs during conditions of induced hypothermia (hand immersed in an ice bath). PPG measurements from 20 volunteers were conducted and SpO 2 values were estimated at all stages of the experiment. Good quality PPG signals were observed from the majority of the volunteers at almost all hand temperatures. At low temperature ranges, from 13 to 21 °C, the failure rate to estimate SpO 2 values from the multimode transreflectance PPG sensor was 2.4% as compared to the commercial pulse oximeter with a failure rate of 70%. (paper)

  19. Effects of blood transfusion on oxygen extraction ratio and central venous saturation in children after cardiac surgery.

    Science.gov (United States)

    Nasser, Bana; Tageldein, Mohmad; AlMesned, Abdulrahman; Kabbani, Mohammad

    2017-01-01

    Red blood cell transfusion is common in critically ill children after cardiac surgery. Since the threshold for hemoglobin (Hb) transfusion need is not well defined, the threshold Hb level at which dependent critical oxygen uptake-to-delivery (VO2-DO2) status compensation is uncertain. To assess the effects of blood transfusion on the oxygen extraction ratio (O2ER) and central venous oxygen saturation (ScvO2) to identify a critical O2ER value that could help us determine the critical need for blood transfusion. Prospective, observational cohort study. Cardiac Surgical Intensive Care Unit at Prince Sultan Cardiac Center in Qassim, Saudi Arabia. Between January 2013 and December 2015, we included all children with cardiac disease who underwent surgery and needed a blood transfusion. Demographic and laboratory data with physiological parameters before and 1 and 6 hours after transfusion were recorded and O2ER before and 6 hours after transfusion was computed. Cases were divided into two groups based on O2ER: Patients with increased O2ER (O2ER > 40%) and normal patients without increased O2ER (O2ER transfusion. Changes in O2ER and ScvO2 following blood transfusion. Of 103 patients who had blood transfusion, 75 cases had normal O2ER before transfusion while 28 cases had increased O2ER before transfusion. Following blood transfusion, O2ER and ScvO2 improved in the group that had increased O2ER before transfusion, but not in the group that had normal O2ER before transfusion. The clinical and hemodynamic indicators O2ER and ScvO2 may be considered as markers that can indicate a need for blood transfusion. The limitation of this study is the small number of patients that had increased O2ER before transfusion. There were few available variables to assess oxygen consumption.

  20. Inspiratory Muscle Training and Arterial Blood Oxygen Saturation in Patients With Chronic Obstructive Pulmonary Disease

    Directory of Open Access Journals (Sweden)

    Bakhshandeh Bavarsad

    2015-01-01

    Full Text Available Background One of the problems of the patients with chronic obstructive pulmonary disease (COPD is the weakness of the respiratory muscles that causes oxygen desaturation at rest and activity and decreases exercise tolerance. Objectives This study aimed to investigate the effect of inspiratory muscle training on arterial oxygen saturation (SPO2. Patients and Methods Forty patients with mild to very severe COPD were recruited for this study, which is a randomized control trail. The patients were randomized to IMT (inspiratory muscle training and control group. Training was performed with Respivol (a kind of inspiratory muscle trainer for 8 weeks (15 min/d for 6 d/week. SPSS software version 16 was used to analyze the data by performing independent t test, paired t test, and Fisher exact test. Results Results showed that, after 8 weeks of inspiratory muscle training, there was a little increase (but not statistically significant improvement in SPO2 (from 92.6 ± 8.71 % to 95.13 ± 7.08 %, with P = 0.06, whereas it remained unchanged in the control group (from 96.0 ± 3.46 % to 96.4 ± 3.35 % with P = 0.51. No statistically significant difference was seen between the two groups (P > 0.05. Conclusions Although inspiratory muscles training can prevent desaturation, which is caused by activity, it fails to improve it.

  1. A new fibre optic pulse oximeter probe for monitoring splanchnic organ arterial blood oxygen saturation.

    Science.gov (United States)

    Hickey, M; Samuels, N; Randive, N; Langford, R; Kyriacou, P A

    2012-12-01

    A new, continuous method of monitoring splanchnic organ oxygen saturation (SpO(2)) would make the early detection of inadequate tissue oxygenation feasible, reducing the risk of hypoperfusion, severe ischaemia, and, ultimately, death. In an attempt to provide such a device, a new fibre optic based reflectance pulse oximeter probe and processing system were developed followed by an in vivo evaluation of the technology on seventeen patients undergoing elective laparotomy. Photoplethysmographic (PPG) signals of good quality and high signal-to-noise ratio were obtained from the small bowel, large bowel, liver and stomach. Simultaneous peripheral PPG signals from the finger were also obtained for comparison purposes. Analysis of the amplitudes of all acquired PPG signals indicated much larger amplitudes for those signals obtained from splanchnic organs than those obtained from the finger. Estimated SpO(2) values for splanchnic organs showed good agreement with those obtained from the finger fibre optic probe and those obtained from a commercial device. These preliminary results suggest that a miniaturized 'indwelling' fibre optic sensor may be a suitable method for pre-operative and post-operative evaluation of splanchnic organ SpO(2) and their health. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  2. Performance evaluation of photoacoustic oximetry imaging systems using a dynamic blood flow phantom with tunable oxygen saturation

    Science.gov (United States)

    Vogt, William C.; Zhou, Xuewen; Andriani, Rudy; Wear, Keith A.; Garra, Brian S.; Pfefer, Joshua

    2018-02-01

    Photoacoustic Imaging (PAI) is an emerging technology with strong potential for broad clinical applications from breast cancer detection to cerebral monitoring due to its ability to compute maps of blood oxygen saturation (SO2) distribution in deep tissues using multispectral imaging. However, no well-validated consensus test methods currently exist for evaluating oximetry-specific performance characteristics of PAI devices. We have developed a phantombased flow system capable of rapid SO2 adjustment to serve as a test bed for elucidation of factors impacting SO2 measurement and quantitative characterization of device performance. The flow system is comprised of a peristaltic pump, membrane oxygenator, oxygen and nitrogen gas, and in-line oxygen, pH, and temperature sensors that enable real-time estimation of SO2 reference values. Bovine blood was delivered through breast-relevant tissue phantoms containing vessel-mimicking fluid channels, which were imaged using a custom multispectral PAI system. Blood was periodically drawn for SO2 measurement in a clinical-grade CO-oximeter. We used this flow phantom system to evaluate the impact of device parameters (e.g.,wavelength-dependent fluence corrections) and tissue parameters (e.g. fluid channel depth, blood SO2, spectral coloring artifacts) on oximetry measurement accuracy. Results elucidated key challenges in PAI oximetry and device design trade-offs, which subsequently allowed for optimization of system performance. This approach provides a robust benchtop test platform that can support PAI oximetry device optimization, performance validation, and clinical translation, and may inform future development of consensus test methods for performance assessment of photoacoustic oximetry imaging systems.

  3. Theoretical model for optical oximetry at the capillary level: exploring hemoglobin oxygen saturation through backscattering of single red blood cells

    Science.gov (United States)

    Liu, Rongrong; Spicer, Graham; Chen, Siyu; Zhang, Hao F.; Yi, Ji; Backman, Vadim

    2017-02-01

    Oxygen saturation (sO2) of red blood cells (RBCs) in capillaries can indirectly assess local tissue oxygenation and metabolic function. For example, the altered retinal oxygenation in diabetic retinopathy and local hypoxia during tumor development in cancer are reflected by abnormal sO2 of local capillary networks. However, it is far from clear whether accurate label-free optical oximetry (i.e., measuring hemoglobin sO2) is feasible from dispersed RBCs at the single capillary level. The sO2-dependent hemoglobin absorption contrast present in optical scattering signal is complicated by geometry-dependent scattering from RBCs. We present a numerical study of backscattering spectra from single RBCs based on the first-order Born approximation, considering practical factors: RBC orientations, size variation, and deformations. We show that the oscillatory spectral behavior of RBC geometries is smoothed by variations in cell size and orientation, resulting in clear sO2-dependent spectral contrast. In addition, this spectral contrast persists with different mean cellular hemoglobin content and different deformations of RBCs. This study shows for the first time the feasibility of, and provides a theoretical model for, label-free optical oximetry at the single capillary level using backscattering-based imaging modalities, challenging the popular view that such measurements are impossible at the single capillary level.

  4. Non-invasive evaluation of blood oxygen saturation and hematocrit from T1 and T2 relaxation times: In-vitro validation in fetal blood.

    Science.gov (United States)

    Portnoy, Sharon; Seed, Mike; Sled, John G; Macgowan, Christopher K

    2017-12-01

    We propose an analytical method for calculating blood hematocrit (Hct) and oxygen saturation (sO 2 ) from measurements of its T 1 and T 2 relaxation times. Through algebraic substitution, established two-compartment relationships describing R1=T1-1 and R2=T2-1 as a function of hematocrit and oxygen saturation were rearranged to solve for Hct and sO 2 in terms of R 1 and R 2 . Resulting solutions for Hct and sO 2 are the roots of cubic polynomials. Feasibility of the method was established by comparison of Hct and sO 2 estimates obtained from relaxometry measurements (at 1.5 Tesla) in cord blood specimens to ground-truth values obtained by blood gas analysis. Monte Carlo simulations were also conducted to assess the effect of T 1 , T 2 measurement uncertainty on precision of Hct and sO 2 estimates. Good agreement was observed between estimated and ground-truth blood properties (bias = 0.01; 95% limits of agreement = ±0.13 for Hct and sO 2 ). Considering the combined effects of biological variability and random measurement noise, we estimate a typical uncertainty of ±0.1 for Hct, sO 2 estimates. Results demonstrate accurate quantification of Hct and sO 2 from T 1 and T 2 . This method is applicable to noninvasive fetal vessel oximetry-an application where existing oximetry devices are unusable or require risky blood-sampling procedures. Magn Reson Med 78:2352-2359, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  5. 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.

  6. One hour effects of salbutamol and formoterol on blood pressure, heart rate and oxygen saturation in asthmatics

    Directory of Open Access Journals (Sweden)

    Geraldo Andrade Capuchinho-Júnior

    2008-05-01

    Full Text Available Aim: To analyse systolic (SBP and diastolic blood pressure (DBP, partial oxygen saturation (SpO2 and heart rate (HR disorders for an hour after short and long acting ß2-agonists. Material and methods: Twenty-four severe persistent asthma Pulmonology outpatients at Hospital Universitario Gaffree e Guinle were selected. SBP, DBP, SpO2 and HR values were determined before and after 400 μg of salbutamol and 12 μg of formoterol, on different days, with a minimum interval of 24 hours. Results: All patients showed ventilatory obstruction, as seen by a reduced FEV1/FVC ratio. There was no statistical SBP/DBP/HR difference after bronchodilator agents, but SpO2 increased with salbutamol. Conclusion: A standard dose of salbutamol and formoterol does not cause haemodynamic disorder. Resumo: Objectivo: Analisar os possíveis efeitos do uso de β-2-agonistas, de curta e longa duração, nas pressões arteriais sistólica (PAS e diastólica (PAD, na saturação parcial de oxigénio (SpO2 e na frequência cardíaca (FC, durante o período de uma hora. Material e métodos: Vinte e quatro doentes com asma persistente grave, em tratamento no ambulatório de Pneumologia do Hospital Universitário Gaffrée e Guinle, foram seleccionados para um ensaio clínico sequencial e cruzado. Os valores da PAS, PAD, SpO2 e FC foram registados antes e após o uso de broncodilatadores, salbutamol 400 μg e formoterol 12 μg, em dias diferentes, com intervalo mínimo de 24 horas. Resultados: Todos os doentes apresentaram distúrbio ventilatório obstrutivo, identificado pela redução da relação entre o volume expiratório forçado no primeiro segundo (VEMS e a capacidade vital forçada (CVF. Após o uso de substância broncodilatadora, não houve variação significativa nas PAS e PAD, nem na FC; porém, a SpO2 aumentou com o uso de salbutamol. Conclusão: Não foram observadas

  7. The effects of arterial carbon dioxide partial pressure and sevoflurane on capillary venous cerebral blood flow and oxygen saturation during craniotomy.

    Science.gov (United States)

    Klein, Klaus Ulrich; Glaser, Martin; Reisch, Robert; Tresch, Achim; Werner, Christian; Engelhard, Kristin

    2009-07-01

    Intraoperative routine monitoring of cerebral blood flow and oxygenation remains a technological challenge. Using the physiological principle of carbon dioxide reactivity of cerebral vasculature, we investigated a recently developed neuromonitoring device (oxygen-to-see, O2C device) for simultaneous measurements of regional cerebral blood flow (rvCBF), blood flow velocity (rvVelo), oxygen saturation (srvO2), and hemoglobin amount (rvHb) at the capillary venous level in patients subjected to craniotomy. Twenty-six neurosurgical patients were randomly assigned to anesthesia with 1.4% or 2.0% sevoflurane end-tidal concentration. After craniotomy, a fiberoptic probe was applied on a macroscopically healthy surface of cerebral tissue next to the site of surgery. Simultaneous measurements in 2 and 8 mm cerebral depth were performed in each patient during lower (35 mm Hg) and higher (45 mm Hg) levels (random order) of arterial carbon dioxide partial pressure (PaCO2). The principle of these measurements relies on the combination of laser-Doppler flowmetry (rvCBF, rvVelo) and photo-spectrometry (srvO2, rvHb). Linear models were fitted to test changes of end points (rvCBF, rvVelo, srvO2, rvHb) in response to lower and higher levels of PaCO2, 1.4% and 2.0% sevoflurane end-tidal concentration, and 2 and 8 mm cerebral depth. RvCBF and rvVelo were elevated by PaCO2 independent of sevoflurane concentration in 2 and 8 mm depth of cerebral tissue (P oxygen was decreased by elevated PaCO2. Unchanged levels of rvHb signify that there was no blood loss during measurements. Data suggest that the device allows detection of local changes in blood flow and oxygen saturation in response to different PaCO2 levels in predominant venous cerebral microvessels.

  8. 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)

    Sheraz, S.; Siddiqi, F.A.

    2015-01-01

    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)

  9. [Study of blood oxygen saturation, heart rate changes and plateau reaction of the Antarctic Kunlun station investigation team in different plateau environments].

    Science.gov (United States)

    Zhao, Shun-yun; Wu, Xin-min; Guo, Ya-min; Zhang, Shu-shun; An, Yan-ming; Li, Bing; Wang, Hao

    2013-06-11

    To explore the blood oxygen saturation and heart rate changes of the Antarctic explorers. During August 2010 to April 2011, the changes in blood oxygen saturation, heart rate and plateau reaction of 16 Antarctic expedition team in different plateau environments (Tibetan plateau versus Antarctic plateau) were monitored with the noninvasive pulse oximeter MD300-C. The extent of acute mountain sickness was determined according to the Lake Louise Consensus acute mountain reaction symptom scores and judgment method. The changes of blood oxygen saturation, heart rate at different altitudes of 110, 3650, 4300 m (96.8% ± 1.2%,89.1% ± 1.2%, 86.1% ± 2.0%, (75.0 ± 5.4) times/min, (104.0 ± 4.3) times/min, (113.0 ± 5.2) times/min,F = 214.155, 240.088,both P rate at different altitudes of 2000, 2500, 3000, 3500 and 4087 m(91.9% ± 1.3%,90.5% ± 1.3%,87.6% ± 1.4%,85.0% ± 1.8%,81.5% ± 2.2%, (85.9 ± 3.2) times/min, (90.6 ± 2.8) times/min, (97.8 ± 4.1) times/min, (102.0 ± 3.4) times/min, (106.3 ± 3.9) times/min, F = 105.418, 90.174, both P rate were both correlated with the risk of altitude sickness (r = -0.446 and 0.565, both P rate of the Antarctic explorers. And with the increases of altitude, the risk of altitude sickness gradually increases.

  10. Renal vein oxygen saturation in renal artery stenosis

    DEFF Research Database (Denmark)

    Nielsen, K; Rehling, M; Henriksen, Jens Henrik Sahl

    1992-01-01

    Renal vein oxygen-saturation was measured in 56 patients with arterial hypertension and unilateral stenosis or occlusion of the renal artery. Oxygen-saturation in blood from the ischaemic kidney (84.4%, range 73-93%) was significantly higher than that from the 'normal' contralateral kidney (81...... than its blood flow. This is probably due to decreased filtration fraction and filtered sodium with subsequent reduction in absolute tubular re-absorption of sodium ions....

  11. Diffuse reflectance spectroscopy for the measurement of tissue oxygen saturation

    International Nuclear Information System (INIS)

    Sircan-Kucuksayan, A; Canpolat, M; Uyuklu, M

    2015-01-01

    Tissue oxygen saturation (StO 2 ) is a useful parameter for medical applications. A spectroscopic method has been developed to detect pathologic tissues, due to a lack of normal blood circulation, by measuring StO 2 . In this study, human blood samples with different levels of oxygen saturation have been prepared and spectra were acquired using an optical fiber probe to investigate the correlation between the oxygen saturation levels and the spectra. A linear correlation between the oxygen saturation and ratio of the intensities (760 nm to 790 nm) of the spectra acquired from blood samples has been found. In a validation study, oxygen saturations of the blood samples were estimated from the spectroscopic measurements with an error of 2.9%. It has also 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. Spectra were acquired from the forearms of 30 healthy volunteers to estimate StO 2 prior to, at the beginning of, after 2 min, and at the release of total vascular occlusion. The average StO 2 of a forearm before and after the two minutes occlusion was significantly different. The results suggested that optical reflectance spectroscopy is a sensitive method to estimate the StO 2 levels of human tissue. The technique developed to measure StO 2 has potential to detect ischemia in real time. (paper)

  12. Femoral venous oxygen saturation is no surrogate for central venous oxygen saturation

    NARCIS (Netherlands)

    van Beest, Paul A.; van der Schors, Alice; Liefers, Henriëtte; Coenen, Ludo G. J.; Braam, Richard L.; Habib, Najib; Braber, Annemarije; Scheeren, Thomas W. L.; Kuiper, Michaël A.; Spronk, Peter E.

    2012-01-01

    Objective: The purpose of our study was to determine if central venous oxygen saturation and femoral venous oxygen saturation can be used interchangeably during surgery and in critically ill patients. Design: Prospective observational controlled study. Setting: Nonacademic university-affiliated

  13. TECHNIQUES OF EVALUATION OF HEMOGLOBIN OXYGEN SATURATION IN CLINICAL OPHTHALMOLOGY

    Directory of Open Access Journals (Sweden)

    S. Yu. Petrov

    2016-01-01

    Full Text Available Oxygen content in body fluids and tissues is an important indicator of life support functions. A number of ocular pathologies, e.g. glaucoma, are of presumable vascular origin which means altered blood supply and oxygen circulation. Most oxygen is transported in the blood in the association with hemoglobin. When passing through the capillaries, hemoglobin releases oxygen, converting from oxygenated form to deoxygenated form. This process is accompanied by the changes in spectral characteristics of hemoglobin which result in different colors of arterial and venous blood. Photometric technique for the measurement of oxygen saturation in blood is based on the differences in light absorption by different forms of hemoglobin. The measurement of saturation is called oximetry. Pulse oximetry with assessment of tissue oxygenation is the most commonly used method in medicine. The degree of hemoglobin oxygen saturation in the eye blood vessels is the most accessible for noninvasive studies during ophthalmoscopy and informative. Numerous studies showed the importance of this parameter for the diagnosis of retinopathy of various genesis, metabolic status analysis in hyperglycemia, diagnosis and control of treatment of glaucoma and other diseases involving alterations in eye blood supply. The specific method for evaluation of oxygen concentration is the measurement of pressure of oxygen dissolved in the blood, i.e. partial pressure of oxygen. In ophthalmological practice, this parameter is measured in anterior chamber fluid evaluating oxygen level for several ophthalmopathies including different forms of glaucoma, for instillations of hypotensive eye drops as well as in vitreous body near to the optic disc under various levels of intraocular pressure. Currently, monitoring of oxygen saturation in retinal blood vessels, i.e. retinal oximetry, is well developed. This technique is based on the assessment of light absorption by blood depending on

  14. Cerebral and Renal Oxygen Saturation Are Not Compromised in the Presence of Retrograde Blood Flow in either the Ascending or Descending Aorta in Term or Near-Term Infants with Left-Sided Obstructive Lesions

    NARCIS (Netherlands)

    van der Laan, Michelle E.; Mebius, Mirthe J.; Roofthooft, Marcus T. R.; Bos, Arend F.; Berger, Rolf M. F.; Kooi, Elisabeth M. W.

    2017-01-01

    Background: In infants with left-sided obstructive lesions (LSOL), the presence of retrograde blood flow in either the ascending or descending aorta may lead to diminished cerebral and renal blood flow, respectively. Objectives: Our aim was to compare cerebral and renal tissue oxygen saturation

  15. A general model to calculate the spin-lattice (T1) relaxation time of blood, accounting for haematocrit, oxygen saturation and magnetic field strength.

    Science.gov (United States)

    Hales, Patrick W; Kirkham, Fenella J; Clark, Christopher A

    2016-02-01

    Many MRI techniques require prior knowledge of the T1-relaxation time of blood (T1bl). An assumed/fixed value is often used; however, T1bl is sensitive to magnetic field (B0), haematocrit (Hct), and oxygen saturation (Y). We aimed to combine data from previous in vitro measurements into a mathematical model, to estimate T1bl as a function of B0, Hct, and Y. The model was shown to predict T1bl from in vivo studies with a good accuracy (± 87 ms). This model allows for improved estimation of T1bl between 1.5-7.0 T while accounting for variations in Hct and Y, leading to improved accuracy of MRI-derived perfusion measurements. © The Author(s) 2015.

  16. Oxygenation of saturated and unsaturated hydrocarbons with ...

    Indian Academy of Sciences (India)

    Unknown

    Oxygenation of saturated and unsaturated hydrocarbons with sodium periodate. 431. Table 1. Competitive oxygenation of tetralin and cyclooctene with sodium periodate catalyzed by different manga- .... Teacher Education University. My grateful thanks also extend to Dr D Mohajer for his useful sugges- tions. References. 1.

  17. The role of central venous oxygen saturation, blood lactate, and central venous-to-arterial carbon dioxide partial pressure difference as a goal and prognosis of sepsis treatment.

    Science.gov (United States)

    Wittayachamnankul, Borwon; Chentanakij, Boriboon; Sruamsiri, Kamphee; Chattipakorn, Nipon

    2016-12-01

    The current practice in treatment of severe sepsis and septic shock is to ensure adequate oxygenation and perfusion in patients, along with prompt administration of antibiotics, within 6 hours from diagnosis, which is considered the "golden hour" for the patients. One of the goals of treatment is to restore normal tissue perfusion. With this goal in mind, some parameters have been used to determine the success of treatment and mortality rate; however, none has been proven to be the best predictor of mortality rate in sepsis patients. Despite growing evidence regarding the prognostic indicators for mortality in sepsis patients, inconsistent reports exist. This review comprehensively summarizes the reports regarding the frequently used parameters in sepsis including central venous oxygen saturation, blood lactate, and central venous-to-arterial carbon dioxide partial pressure difference, as prognostic indicators for clinical outcomes in sepsis patients. Moreover, consistent findings and inconsistent reports for their pathophysiology and the potential mechanisms for their use as well as their limitations in sepsis patients are presented and discussed. Finally, a schematic strategy for potential management and benefits in sepsis patients is proposed based upon these current available data. There is currently no ideal biomarker that can indicate prognosis, predict progression of the disease, and guide treatment in sepsis. Further studies are needed to be carried out to identify the ideal biomarker that has all the desired properties. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. 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.

  19. Investigation of photoplethysmographic signals and blood oxygen saturation values on healthy volunteers during cuff-induced hypoperfusion using a multimode PPG/SpO₂ sensor.

    Science.gov (United States)

    Shafique, M; Kyriacou, P A; Pal, S K

    2012-06-01

    Photoplethysmography (PPG) is a technique widely used to monitor volumetric blood changes induced by cardiac pulsations. Pulse oximetry uses the technique of PPG to estimate arterial oxygen saturation values (SpO₂). In poorly perfused tissues, SpO₂ readings may be compromised due to the poor quality of the PPG signals. A multimode finger PPG probe that operates simultaneously in reflectance, transmittance and a combined mode called "transreflectance" was developed, in an effort to improve the quality of the PPG signals in states of hypoperfusion. Experiments on 20 volunteers were conducted to evaluate the performance of the multimode PPG sensor and compare the results with a commercial transmittance pulse oximeter. A brachial blood pressure cuff was used to induce artificial hypoperfusion. Results showed that the amplitude of the transreflectance AC PPG signals were significantly different (p signals obtained from the other two conventional PPG sensors (reflectance and transmittance). At induced brachial pressures between 90 and 135 mmHg, the reflectance finger pulse oximeter failed 25 times (failure rate 42.2 %) to estimate SpO₂ values, whereas the transmittance pulse oximeter failed 8 times (failure rate 15.5 %). The transreflectance pulse oximeter failed only 3 times (failure rate 6.8 %) and the commercial pulse oximeter failed 17 times (failure rate 29.4 %).

  20. Femoral venous oxygen saturation is no surrogate for central venous oxygen saturation

    NARCIS (Netherlands)

    van Beest, Paul A.; van der Schors, Alice; Liefers, Henriette; Coenen, Ludo G. J.; Braam, Richard L.; Habib, Najib; Braber, Annemarije; Scheeren, Thomas W. L.; Kuiper, Michael A.; Spronk, Peter E.

    2012-01-01

    Objective:  The purpose of our study was to determine if central venous oxygen saturation and femoral venous oxygen saturation can be used interchangeably during surgery and in critically ill patients. Design:  Prospective observational controlled study. Setting:  Nonacademic university-affiliated

  1. Society of cardiovascular anesthesiologists: the effect of blood pressure regulation during aortic coarctation repair on brain, kidney, and muscle oxygen saturation measured by near-infrared spectroscopy: a randomized, clinical trial

    NARCIS (Netherlands)

    Moerman, Annelies; Bové, Thierry; François, Katrien; Jacobs, Stefan; Deblaere, Isabel; Wouters, Patrick; de Hert, Stefan

    2013-01-01

    In this study, we compared the effects of 3 frequently used arterial blood pressure-regulating agents on brain (rScO2), renal (SrO2), and muscle (SmO2) oxygen saturation, during aortic coarctation repair in children. Based on the reported adverse effect of sodium nitroprusside (SNP) on left-sided

  2. Relating oxygen partial pressure, saturation and content: the haemoglobin-oxygen dissociation curve.

    Science.gov (United States)

    Collins, Julie-Ann; Rudenski, Aram; Gibson, John; Howard, Luke; O'Driscoll, Ronan

    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 (S O2 ) and partial pressure, haemoglobin concentration and cardiac output, including its distribution. The haemoglobin-oxygen dissociation curve, a graphical representation of the relationship between oxygen satur-ation 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 S O2 in blood from patients with normal pH and S O2 >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 (S pO2 ) 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 (S aO2 ) as many patients who are not at risk of hypercapnic respiratory failure or metabolic acidosis and have acceptable S pO2 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.

  3. Oxygen general saturation after bronchography under general ...

    African Journals Online (AJOL)

    Thirty-six patients undergoing bronchography or bronchoscopy under general anaesthesia were continuously monitored by pulse oximetry for 5 hours after these procedures. Significant falls in oxygen saturation were observed in the first hour and were of most clinical relevance in patients with preexisting pulmonary ...

  4. Central venous oxygen saturation during hypovolaemic shock in humans

    DEFF Research Database (Denmark)

    Madsen, P; Iversen, H; Secher, N H

    1993-01-01

    We compared central venous oxygen saturation and central venous pressure (CVP) as indices of the effective blood volume during 50 degrees head-up tilt (anti-Trendelenburg's position) induced hypovolaemic shock in eight healthy subjects. Head-up tilt increased thoracic electrical impedance from 31...... (28-36) (median and range) to 34 (30-40) Ohm, mean arterial pressure (MAP) from 79 (70-88) to 86 (80-99) mmHg, heart rate (HR) from 67 (56-71) to 99 (78-119) beats min-1 (p ....05) but thereafter remained stable. In contrast, central venous oxygen saturation showed a linear decrease with time from 0.75 (0.69-0.78) at rest to 0.60 (0.49-0.67) (p measurement of central venous oxygen saturation...

  5. In vivo detection of hemoglobin oxygen saturation and carboxyhemoglobin saturation with multiwavelength photoacoustic microscopy.

    Science.gov (United States)

    Chen, Zhongjiang; Yang, Sihua; Xing, Da

    2012-08-15

    A method for noninvasively detecting hemoglobin oxygen saturation (SO2) and carboxyhemoglobin saturation (SCO) in subcutaneous microvasculature with multiwavelength photoacoustic microscopy is presented. Blood samples mixed with different concentrations of carboxyhemoglobin were used to test the feasibility and accuracy of photoacoustic microscopy compared with the blood-gas analyzer. Moreover, fixed-point detection of SO2 and SCO in mouse ear was obtained, and the changes from normoxia to carbon monoxide hypoxia were dynamically monitored in vivo. Experimental results demonstrate that multiwavelength photoacoustic microscopy can detect SO2 and SCO, which has future potential clinical applications.

  6. Interleaved quantitative BOLD: Combining extravascular R2' - and intravascular R2-measurements for estimation of deoxygenated blood volume and hemoglobin oxygen saturation.

    Science.gov (United States)

    Lee, Hyunyeol; Englund, Erin K; Wehrli, Felix W

    2018-03-23

    Quantitative BOLD (qBOLD), a non-invasive MRI method for assessment of hemodynamic and metabolic properties of the brain in the baseline state, provides spatial maps of deoxygenated blood volume fraction (DBV) and hemoglobin oxygen saturation (HbO 2 ) by means of an analytical model for the temporal evolution of free-induction-decay signals in the extravascular compartment. However, mutual coupling between DBV and HbO 2 in the signal model results in considerable estimation uncertainty precluding achievement of a unique set of solutions. To address this problem, we developed an interleaved qBOLD method (iqBOLD) that combines extravascular R 2 ' and intravascular R 2 mapping techniques so as to obtain prior knowledge for the two unknown parameters. To achieve these goals, asymmetric spin echo and velocity-selective spin-labeling (VSSL) modules were interleaved in a single pulse sequence. Prior to VSSL, arterial blood and CSF signals were suppressed to produce reliable estimates for cerebral venous blood volume fraction (CBV v ) as well as venous blood R 2 (to yield HbO 2 ). Parameter maps derived from the VSSL module were employed to initialize DBV and HbO 2 in the qBOLD processing. Numerical simulations and in vivo experiments at 3 T were performed to evaluate the performance of iqBOLD in comparison to the parent qBOLD method. Data obtained in eight healthy subjects yielded plausible values averaging 60.1 ± 3.3% for HbO 2 and 3.1 ± 0.5 and 2.0 ± 0.4% for DBV in gray and white matter, respectively. Furthermore, the results show that prior estimates of CBV v and HbO 2 from the VSSL component enhance the solution stability in the qBOLD processing, and thus suggest the feasibility of iqBOLD as a promising alternative to the conventional technique for quantifying neurometabolic parameters. Copyright © 2018. Published by Elsevier Inc.

  7. 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.

  8. Development of an oxygen saturation measuring system by using near-infrared spectroscopy

    Science.gov (United States)

    Kono, K.; Nakamachi, E.; Morita, Y.

    2017-08-01

    Recently, the hypoxia imaging has been recognized as the advanced technique to detect cancers because of a strong relationship with the biological characterization of cancer. In previous studies, hypoxia imaging systems for endoscopic diagnosis have been developed. However, these imaging technologies using the visible light can observe only blood vessels in gastric mucous membrane. Therefore, they could not detect scirrhous gastric cancer which accounts for 10% of all gastric cancers and spreads rapidly into submucous membrane. To overcome this problem, we developed a measuring system of blood oxygen saturation in submucous membrane by using near-infrared (NIR) spectroscopy. NIR, which has high permeability for bio-tissues and high absorbency for hemoglobin, can image and observe blood vessels in submucous membrane. NIR system with LED lights and a CCD camera module was developed to image blood vessels. We measured blood oxygen saturation using the optical density ratio (ODR) of two wavelengths, based on Lambert-Beer law. To image blood vessel clearly and measure blood oxygen saturation accurately, we searched two optimum wavelengths by using a multilayer human gastric-like phantom which has same optical properties as human gastric one. By using Monte Carlo simulation of light propagation, we derived the relationship between the ODR and blood oxygen saturation and elucidated the influence of blood vessel depth on measuring blood oxygen saturation. The oxygen saturation measuring methodology was validated with experiments using our NIR system. Finally, it was confirmed that our system can detect oxygen saturation in various depth blood vessels accurately.

  9. Correlation of results obtained by in-vivo optical spectroscopy with measured blood oxygen saturation using a positive linear regression fit

    Science.gov (United States)

    McCormick, Patrick W.; Lewis, Gary D.; Dujovny, Manuel; Ausman, James I.; Stewart, Mick; Widman, Ronald A.

    1992-05-01

    Near infrared light generated by specialized instrumentation was passed through artificially oxygenated human blood during simultaneous sampling by a co-oximeter. Characteristic absorption spectra were analyzed to calculate the ratio of oxygenated to reduced hemoglobin. A positive linear regression fit between diffuse transmission oximetry and measured blood oxygenation over the range 23% to 99% (r2 equals .98, p signal was observed in the patient over time. The procedure was able to be performed clinically without difficulty; rSO2 values recorded continuously demonstrate the usefulness of the technique. Using the same instrumentation, arterial input and cerebral response functions, generated by IV tracer bolus, were deconvoluted to measure mean cerebral transit time. Date collected over time provided a sensitive index of changes in cerebral blood flow as a result of therapeutic maneuvers.

  10. In vivo integrated photoacoustic and confocal microscopy of hemoglobin oxygen saturation and oxygen partial pressure.

    Science.gov (United States)

    Wang, Yu; Hu, Song; Maslov, Konstantin; Zhang, Yu; Xia, Younan; Wang, Lihong V

    2011-04-01

    We developed dual-modality microscope integrating photoacoustic microscopy (PAM) and fluorescence confocal microscopy (FCM) to noninvasively image hemoglobin oxygen saturation (sO₂) and oxygen partial pressure (pO₂) in vivo in single blood vessels with high spatial resolution. While PAM measures sO₂ by imaging hemoglobin optical absorption at two wavelengths, FCM quantifies pO₂ using phosphorescence quenching. The variations of sO₂ and pO₂ values in multiple orders of vessel branches under hyperoxic (100% oxygen) and normoxic (21% oxygen) conditions correlate well with the oxygen-hemoglobin dissociation curve. In addition, the total concentration of hemoglobin is imaged by PAM at an isosbestic wavelength.

  11. Quantification of photocatalytic oxygenation of human blood.

    Science.gov (United States)

    Subrahmanyam, Aryasomayajula; Thangaraj, Paul R; Kanuru, Chandrasekhar; Jayakumar, Albert; Gopal, Jayashree

    2014-04-01

    Photocatalytic oxygenation of human blood is an emerging concept based on the principle of photocatalytic splitting of water into oxygen and hydrogen. This communication reports: (i) a design of a photocatalytic cell (PC) that separates the blood from UV (incident) radiation source, (ii) a pH, temperature and flow controlled circuit designed for quantifying the oxygenation of human blood by photocatalysis and (iii) measuring the current efficacy of ITO/TiO2 nano thin films in oxygenating human blood in a dynamic circuit in real time. The average increase in oxygen saturation was around 5% above baseline compared to control (p<0.0005). We believe this is one of the first attempts to quantify photocatalytic oxygenation of human blood under controlled conditions. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

  12. Correlation between Oxygen Saturation and Hemoglobin and Hematokrit Levels in Tetralogy of Fallot Patients

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    Farhatul Inayah Adiputri

    2016-03-01

    Full Text Available Background: Hemoglobin and hematocrit levels increase in Tetralogy of Fallot (TOF but the oxygen saturation declines. Reduced hemoglobin in circulating blood as a parameter of cyanosis does not indicate rising hemoglobin due to the ‘not-working’ hemoglobins that affect the oxygen saturation. Increasing hematocrit is the result of secondary erythrocytosis caused by declining oxygen level in blood, which is related to the oxygen saturation. This study was conducted to find the correlation between oxygen saturation and hemoglobin and hematocrite levels in TOF patients. Methods: This study was undertaken at Dr. Hasan Sadikin General Hospital in the period of January 2011 to December 2012 using the cross-sectional analytic method with total sampling technique. Inclusion criteria were medical records of TOF patients diagnosed based on echocardiography that included data on oxygen saturation, hemoglobin, and hematocrite. Exclusion criteria was the history of red blood transfusion. Results: Thirty medical records of TOF patiens from Dr. Hasan Sadikin General Hospital Bandung were included in this study. Due to skewed data distribution, Spearman correlation test was used to analyze the data. There was a significant negative correlation between oxygen saturation and hematocrit level (r= -0.412; p=0.024 and insignificant correlation between oxygen saturation and hemoglobin (r=-0.329; p= 0.076. Conclusions: There is a weak negative correlation between oxygen saturation and hematocrite levels

  13. Cerebral and Renal Oxygen Saturation Are Not Compromised in the Presence of Retrograde Blood Flow in either the Ascending or Descending Aorta in Term or Near-Term Infants with Left-Sided Obstructive Lesions.

    Science.gov (United States)

    van der Laan, Michelle E; Mebius, Mirthe J; Roofthooft, Marcus T R; Bos, Arend F; Berger, Rolf M F; Kooi, Elisabeth M W

    2017-01-01

    In infants with left-sided obstructive lesions (LSOL), the presence of retrograde blood flow in either the ascending or descending aorta may lead to diminished cerebral and renal blood flow, respectively. Our aim was to compare cerebral and renal tissue oxygen saturation (rSO2) between infants with LSOL with antegrade and retrograde blood flow in the ascending aorta and with and without diastolic backflow in the descending aorta. Based on 2 echocardiograms, the study group was categorized according to the direction of blood flow in the ascending and descending aorta. We measured cerebral and renal rSO2 using near-infrared spectroscopy and calculated fractional tissue oxygen extraction (FTOE). Nineteen infants with LSOL, admitted to the NICU between 0 and 28 days after birth, were included. Infants with antegrade blood flow (n = 12) and infants with retrograde blood flow in the ascending aorta (n = 7) had similar cerebral rSO2 and FTOE during both echocardiograms. Only during the first echocardiogram, infants with retrograde blood flow in the ascending aorta had lower renal FTOE (0.14 vs. 0.32, p = 0.04) and tended to have higher renal rSO2 (80 vs. 65%, p = 0.09). The presence of diastolic backflow in the descending aorta was not associated with cerebral or renal rSO2 and FTOE during the first (n = 8) as well as the second echocardiogram (n = 10). Retrograde blood flow in the ascending aorta was not associated with cerebral oxygenation, while diastolic backflow in the descending aorta was not associated with renal oxygenation in infants with LSOL. © 2017 S. Karger AG, Basel.

  14. Monitor hemoglobin concentration and oxygen saturation in living mouse tail using photoacoustic CT scanner

    Science.gov (United States)

    Liu, Bo; Kruger, Robert; Reinecke, Daniel; Stantz, Keith M.

    2010-02-01

    Purpose: The purpose of this study is to use PCT spectroscopy scanner to monitor the hemoglobin concentration and oxygen saturation change of living mouse by imaging the artery and veins in a mouse tail. Materials and Methods: One mouse tail was scanned using the PCT small animal scanner at the isosbestic wavelength (796nm) to obtain its hemoglobin concentration. Immediately after the scan, the mouse was euthanized and its blood was extracted from the heart. The true hemoglobin concentration was measured using a co-oximeter. Reconstruction correction algorithm to compensate the acoustic signal loss due to the existence of bone structure in the mouse tail was developed. After the correction, the hemoglobin concentration was calculated from the PCT images and compared with co-oximeter result. Next, one mouse were immobilized in the PCT scanner. Gas with different concentrations of oxygen was given to mouse to change the oxygen saturation. PCT tail vessel spectroscopy scans were performed 15 minutes after the introduction of gas. The oxygen saturation values were then calculated to monitor the oxygen saturation change of mouse. Results: The systematic error for hemoglobin concentration measurement was less than 5% based on preliminary analysis. Same correction technique was used for oxygen saturation calculation. After correction, the oxygen saturation level change matches the oxygen volume ratio change of the introduced gas. Conclusion: This living mouse tail experiment has shown that NIR PCT-spectroscopy can be used to monitor the oxygen saturation status in living small animals.

  15. Validation of the Nonin 8600V Pulse Oximeter for heart rate and oxygen saturation measurements in rats.

    Science.gov (United States)

    Bernard, Susan L; An, Dowon; Glenny, Robb W

    2004-05-01

    This report validates the use and limitations of the Nonin Pulse Oximeter for measuring heart rate and oxygen saturation in rats. Eight anesthetized Sprague-Dawley rats were intubated and catheterized. Oxygen saturation was directly measured from arterial blood by using a Radiometer OSM3 Hemoximeter adjusted for rat blood as well as indirectly by using the Nonin Pulse Oximeter. Oxygen saturation was changed by varying the level of inhaled oxygen. Heart rate was measured in two ways: 1) by using the signal from the Nonin Pulse Oximeter and 2) by counting the pressure pulses from the transduced blood pressure. There was excellent agreement between heart rate values measured by the Nonin Pulse Oximeter and that measured by counting the pulses from the arterial blood pressure recording. The Nonin Pulse Oximeter underestimated oxygen saturations by about 3% to 5% compared to the Hemoximeter. Overall, the pulse oximeter reflected important trends in oxygen saturations, making it a useful tool for laboratory animal medicine.

  16. 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.

  17. The influence of systemic hemodynamics and oxygen transport on cerebral oxygen saturation in neonates after the Norwood procedure.

    Science.gov (United States)

    Li, Jia; Zhang, Gencheng; Holtby, Helen; Guerguerian, Anne-Marie; Cai, Sally; Humpl, Tilman; Caldarone, Christopher A; Redington, Andrew N; Van Arsdell, Glen S

    2008-01-01

    Ischemic brain injury is an important morbidity in neonates after the Norwood procedure. Its relationship to systemic hemodynamic oxygen transport is poorly understood. Sixteen neonates undergoing the Norwood procedure were studied. Continuous cerebral oxygen saturation was measured by near-infrared spectroscopy. Continuous oxygen consumption was measured by respiratory mass spectrometry. Pulmonary and systemic blood flow, systemic vascular resistance, oxygen delivery, and oxygen extraction ratio were derived with measurements of arterial, and superior vena cava and pulmonary venous gases and pressures at 2- to 4-hour intervals during the first 72 hours in the intensive care unit. Mean cerebral oxygen saturation was 66% +/- 12% before the operation, reduced to 51% +/- 13% on arrival in the intensive care unit, and remained low during the first 8 hours; it increased to 56% +/- 9% at 72 hours, still significantly lower than the preoperative level (P blood flow and oxygen delivery (P blood flow (P = .001) and hemoglobin (P = .02) and negatively correlated with systemic vascular resistance (P = .003). It was not correlated with oxygen consumption (P > .05). Cerebral oxygen saturation decreased significantly in neonates during the early postoperative period after the Norwood procedure and was significantly influenced by systemic hemodynamic and metabolic events. As such, hemodynamic interventions to modify systemic oxygen transport may provide further opportunities to reduce the risk of cerebral ischemia and improve neurodevelopmental outcomes.

  18. Agreement between arterial partial pressure of carbon dioxide and saturation of hemoglobin with oxygen values obtained by direct arterial blood measurements versus noninvasive methods in conscious healthy and ill foals.

    Science.gov (United States)

    Wong, David M; Alcott, Cody J; Wang, Chong; Bornkamp, Jennifer L; Young, Jessica L; Sponseller, Brett A

    2011-11-15

    To determine agreement between indirect measurements of end-tidal partial pressure of carbon dioxide (PetCO(2)) and saturation of hemoglobin with oxygen as measured by pulse oximetry (SpO(2)) with direct measurements of PaCO(2) and calculated saturation of hemoglobin with oxygen in arterial blood (SaO(2)) in conscious healthy and ill foals. Validation study. 10 healthy and 21 ill neonatal foals. Arterial blood gas analysis was performed on healthy and ill foals examined at a veterinary teaching hospital to determine direct measurements of PaCO(2) and PaO(2) along with SaO(2). Concurrently, PetCO(2) was measured with a capnograph inserted into a naris, and SpO(2) was measured with a reflectance probe placed at the base of the tail. Paired values were compared by use of Pearson correlation coefficients, and level of agreement was assessed with the Bland-Altman method. Mean ± SD difference between PaCO(2) and PetCO(2) was 0.1 ± 5.0 mm Hg. There was significant strong correlation (r = 0.779) and good agreement between PaCO(2) and PetCO(2). Mean ± SD difference between SaO(2) and SpO(2) was 2.5 ± 3.5%. There was significant moderate correlation (r = 0.499) and acceptable agreement between SaO(2) and SpO(2). Both PetCO(2) obtained by use of nasal capnography and SpO(2) obtained with a reflectance probe are clinically applicable and accurate indirect methods of estimating and monitoring PaCO(2) and SaO(2) in neonatal foals. Indirect methods should not replace periodic direct measurement of corresponding parameters.

  19. Retinal oxygen saturation before and after glaucoma surgery.

    Science.gov (United States)

    Nitta, Eri; Hirooka, Kazuyuki; Shimazaki, Takeru; Sato, Shino; Ukegawa, Kaori; Nakano, Yuki; Tsujikawa, Akitaka

    2017-08-01

    This study compared retinal vessel oxygen saturation before and after glaucoma surgery. Retinal oxygen saturation in glaucoma patients was measured using a non-invasive spectrophotometric retinal oximeter. Adequate image quality was found in 49 of the 108 consecutive glaucoma patients recruited, with 30 undergoing trabeculectomy, 11 EX-PRESS and eight trabeculotomy. Retinal oxygen saturation measurements in the retinal arterioles and venules were performed at 1 day prior to and at approximately 10 days after surgery. Statistical analysis was performed using a Student's t-test. After glaucoma surgery, intraocular pressure (IOP) decreased from 19.8 ± 7.7 mmHg to 9.0 ± 5.7 mmHg (p glaucoma surgery had an effect on the retinal venous oxygen saturation. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  20. Rapid determination of oxygen saturation and vascularity for cancer detection.

    Directory of Open Access Journals (Sweden)

    Fangyao Hu

    Full Text Available A rapid heuristic ratiometric analysis for estimating tissue hemoglobin concentration and oxygen saturation from measured tissue diffuse reflectance spectra is presented. The analysis was validated in tissue-mimicking phantoms and applied to clinical measurements in head and neck, cervical and breast tissues. The analysis works in two steps. First, a linear equation that translates the ratio of the diffuse reflectance at 584 nm and 545 nm to estimate the tissue hemoglobin concentration using a Monte Carlo-based lookup table was developed. This equation is independent of tissue scattering and oxygen saturation. Second, the oxygen saturation was estimated using non-linear logistic equations that translate the ratio of the diffuse reflectance spectra at 539 nm to 545 nm into the tissue oxygen saturation. Correlations coefficients of 0.89 (0.86, 0.77 (0.71 and 0.69 (0.43 were obtained for the tissue hemoglobin concentration (oxygen saturation values extracted using the full spectral Monte Carlo and the ratiometric analysis, for clinical measurements in head and neck, breast and cervical tissues, respectively. The ratiometric analysis was more than 4000 times faster than the inverse Monte Carlo analysis for estimating tissue hemoglobin concentration and oxygen saturation in simulated phantom experiments. In addition, the discriminatory power of the two analyses was similar. These results show the potential of such empirical tools to rapidly estimate tissue hemoglobin in real-time spectral imaging applications.

  1. 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.

  2. 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.

    Science.gov (United States)

    Abbasinia, Mohammad; Irajpour, Alireza; Babaii, Atye; Shamali, Mehdi; Vahdatnezhad, Jahanbakhsh

    2014-09-01

    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. 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. 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.

  3. Oxygen saturation index and severity of hypoxic respiratory failure.

    Science.gov (United States)

    Rawat, Munmun; Chandrasekharan, Praveen K; Williams, Ashley; Gugino, Sylvia; Koenigsknecht, Carmon; Swartz, Daniel; Ma, Chang Xing; Mathew, Bobby; Nair, Jayasree; Lakshminrusimha, Satyan

    2015-01-01

    The oxygenation index (OI = mean airway pressure, MAP × FiO2 × 100 : PaO2) is used to assess the severity of hypoxic respiratory failure (HRF) and persistent pulmonary hypertension of the newborn (PPHN). An indwelling arterial line or arterial punctures are necessary to obtain PaO2 for the calculation of OI. Oxygenation can be continuously and noninvasively assessed using pulse oximetry. The use of the oxygen saturation index (OSI = MAP × FiO2 × 100 : SpO2) can be an alternate method of assessing the severity of HRF. To evaluate the correlation between OSI and OI in the following: (1) neonates with HRF and (2) a lamb model of meconium aspiration syndrome. Human neonates: a retrospective chart review of 74 ventilated late preterm/term neonates with indwelling arterial access and SpO2 values in the first 24 h of life was conducted. OSI and OI were calculated and correlated. Lamb model: arterial blood gases were drawn and preductal SpO2 was documented in 40 term newborn lambs with asphyxia and meconium aspiration. OI and OSI were calculated and correlated with pulmonary vascular resistance (PVR). Mean values of OSI and OI showed a correlation coefficient of 0.952 in neonates (mean value of 308 observations in 74 neonates) and 0.948 in lambs (mean value of 743 observations in 40 lambs). In lambs, with increasing PVR, there was a decrease in OI and OSI. OSI correlates significantly with OI in infants with HRF. This noninvasive measure may be used to assess the severity of HRF and PPHN in neonates without arterial access. © 2015 S. Karger AG, Basel

  4. Validation of the CORB75 (confusion, oxygen saturation, respiratory rate, blood pressure, and age ≥ 75 years) as a simpler pneumonia severity rule.

    Science.gov (United States)

    Ochoa-Gondar, O; Vila-Corcoles, A; Rodriguez-Blanco, T; Hospital, I; Salsench, E; Ansa, X; Saun, N

    2014-04-01

    This study compares the ability of two simpler severity rules (classical CRB65 vs. proposed CORB75) in predicting short-term mortality in elderly patients with community-acquired pneumonia (CAP). A population-based study was undertaken involving 610 patients ≥ 65 years old with radiographically confirmed CAP diagnosed between 2008 and 2011 in Tarragona, Spain (350 cases in the derivation cohort, 260 cases in the validation cohort). Severity rules were calculated at the time of diagnosis, and 30-day mortality was considered as the dependent variable. The area under the receiver operating characteristic curves (AUC) was used to compare the discriminative power of the severity rules. Eighty deaths (46 in the derivation and 34 in the validation cohorts) were observed, which gives a mortality rate of 13.1 % (15.6 % for hospitalized and 3.3 % for outpatient cases). After multivariable analyses, besides CRB (confusion, respiration rate ≥ 30/min, systolic blood pressure AUC statistics for predicting mortality in the derivation and validation cohorts were 0.79 and 0.82, respectively. In the derivation cohort, a CORB75 score ≥ 2 showed 78.3 % sensitivity and 65.5 % specificity for mortality (in the validation cohort, these were 82.4 and 71.7 %, respectively). The proposed CORB75 scoring system has good discriminative power in predicting short-term mortality among elderly people with CAP, which supports its use for severity assessment of these patients in primary care.

  5. Reliable monitoring of oxygen saturation via pulse oximetry: Which ...

    African Journals Online (AJOL)

    This study focuses on identifying the best site for placement of pulse oximeter probe accurate measuring of oxygen saturation. Twenty-three healthy male volunteers aged 20 to 40 years old were recruited in this study. Cold pressor test was done to stim 460 measurements of SpO2level were obtained throughout the study.

  6. 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

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    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

  7. Prediction of saturation using the carbon/oxygen log

    Energy Technology Data Exchange (ETDEWEB)

    Horner, S.C.; Sanyal, S.K.

    1984-09-01

    This project investigates the nature of Dresser-Atlas Carbon/Oxygen Log gamma ray spectra. It presents an attempt to improve the signal-to-noise ratio of the C/O and Si/Ca parameters used by Dresser-Atlas to determine oil saturation. Two techniques were developed to subtract the Compton background from the spectral data. Neither technique significantly improves the accuracy of the cased-hole prediction of oil saturation. However, it has been shown that it is possible to develop a satisfactory correlation for oil saturation on a well-by-well basis. This correlation can then be used to generate oil-in-place from the C/O and Si/Ca ratios. 17 references.

  8. 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.

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    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.

  9. Cerebral oxygen saturation and cardiac output during anaesthesia in sitting position for neurosurgical procedures: a prospective observational study.

    Science.gov (United States)

    Schramm, P; Tzanova, I; Hagen, F; Berres, M; Closhen, D; Pestel, G; Engelhard, K

    2016-10-01

    Neurosurgical operations in the dorsal cranium often require the patient to be positioned in a sitting position. This can be associated with decreased cardiac output and cerebral hypoperfusion, and possibly, inadequate cerebral oxygenation. In the present study, cerebral oxygen saturation was measured during neurosurgery in the sitting position and correlated with cardiac output. Perioperative cerebral oxygen saturation was measured continuously with two different monitors, INVOS ® and FORE-SIGHT ® . Cardiac output was measured at eight predefined time points using transoesophageal echocardiography. Forty patients were enrolled, but only 35 (20 female) were eventually operated on in the sitting position. At the first time point, the regional cerebral oxygen saturation measured with INVOS ® was 70 (sd 9)%; thereafter, it increased by 0.0187% min -1 (P<0.01). The cerebral tissue oxygen saturation measured with FORE-SIGHT ® started at 68 (sd 13)% and increased by 0.0142% min -1 (P<0.01). The mean arterial blood pressure did not change. Cardiac output was between 6.3 (sd 1.3) and 7.2 (1.8) litre min -1 at the predefined time points. Cardiac output, but not mean arterial blood pressure, showed a positive and significant correlation with cerebral oxygen saturation. During neurosurgery in the sitting position, the cerebral oxygen saturation slowly increases and, therefore, this position seems to be safe with regard to cerebral oxygen saturation. Cerebral oxygen saturation is stable because of constant CO and MAP, while the influence of CO on cerebral oxygen saturation seems to be more relevant. NCT01275898. © The Author 2016. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Retinal Vessel Oxygen Saturation during 100% Oxygen Breathing in Healthy Individuals.

    Directory of Open Access Journals (Sweden)

    Olof Birna Olafsdottir

    Full Text Available To detect how systemic hyperoxia affects oxygen saturation in retinal arterioles and venules in healthy individuals.Retinal vessel oxygen saturation was measured in 30 healthy individuals with a spectrophotometric retinal oximeter (Oxymap T1. Oximetry was performed during breathing of room air, 100% oxygen (10 minutes, 6L/min and then again room air (10 minutes recovery.Mean oxygen saturation rises modestly in retinal arterioles during 100% oxygen breathing (94.5%±3.8 vs. 92.0%±3.7% at baseline, p<0.0001 and dramatically in retinal venules (76.2%±8.0% vs. 51.3%±5.6%, p<0.0001. The arteriovenous difference decreased during 100% oxygen breathing (18.3%±9.0% vs. 40.7%±5.7%, p<0.0001. The mean diameter of arterioles decreased during 100% oxygen breathing compared to baseline (9.7±1.4 pixels vs. 10.3±1.3 pixels, p<0.0001 and the same applies to the mean venular diameter (11.4±1.2 pixels vs. 13.3±1.5 pixels, p<0.0001.Breathing 100% oxygen increases oxygen saturation in retinal arterioles and more so in venules and constricts them compared to baseline levels. The dramatic increase in oxygen saturation in venules reflects oxygen flow from the choroid and the unusual vascular anatomy and oxygen physiology of the eye.

  11. Design of pulse oximetry signal based on personal computer for detection oxygen saturation

    International Nuclear Information System (INIS)

    Umi Salamah; Margi Sasono

    2015-01-01

    The lack or excess of oxygen in the blood will cause healthy and body system disorder. At certain level, the disease can lead to death. For that reason, the information about oxygen saturation in blood becomes important to be identified. One of the devices used to monitor the blood oxygen saturation is pulse oximetry. This research attempt to designed Pulse Oximetry based on personal computer using red LED and infrared as its light source, while the light sensor using photodiode. The designed Pulse Oximetry is a non-invasive instrumentation which LED drivers is placed on the fingertips. The LED light goes through the finger will be a signal that is fed to the photodiode and will be converted into digital signals by ADC (Analog to Digital Converter) and will be processed further by a personal computer to display the pulse oximetry graphics. This study uses Delphi 7, Microsoft Excel, and Mt Lab as its software.This designed pulse oximetry has been tested in two peoples: sample A, male 38 years; and sample B, a woman 23 years old. Oxygen saturation of sample A is 80.75, while the sample B is 90.75. (author)

  12. A technique for measuring oxygen saturation in biological tissues based on diffuse optical spectroscopy

    Science.gov (United States)

    Kleshnin, Mikhail; Orlova, Anna; Kirillin, Mikhail; Golubiatnikov, German; Turchin, Ilya

    2017-07-01

    A new approach to optical measuring blood oxygen saturation was developed and implemented. This technique is based on an original three-stage algorithm for reconstructing the relative concentration of biological chromophores (hemoglobin, water, lipids) from the measured spectra of diffusely scattered light at different distances from the probing radiation source. The numerical experiments and approbation of the proposed technique on a biological phantom have shown the high reconstruction accuracy and the possibility of correct calculation of hemoglobin oxygenation in the presence of additive noise and calibration errors. The obtained results of animal studies have agreed with the previously published results of other research groups and demonstrated the possibility to apply the developed technique to monitor oxygen saturation in tumor tissue.

  13. 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.

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

    Science.gov (United States)

    Di Caprio, Giuseppe; Stokes, Chris; Higgins, John M; Schonbrun, Ethan

    2015-08-11

    Oxygen is transported throughout the body by hemoglobin (Hb) in red blood cells (RBCs). Although the oxygen affinity of blood is well-understood and routinely assessed in patients by pulse oximetry, variability at the single-cell level has not been previously measured. In contrast, single-cell measurements of RBC volume and Hb concentration are taken millions of times per day by clinical hematology analyzers, and they 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 Hb concentration for individual RBCs in high throughput. We find that the variability in single-cell saturation peaks at an oxygen partial pressure of 2.9%, which corresponds to the maximum slope of the oxygen-Hb dissociation curve. In addition, single-cell oxygen affinity is positively correlated with Hb concentration but independent of osmolarity, which suggests variation in the Hb to 2,3-diphosphoglycerate (2-3 DPG) ratio on a cellular level. By quantifying the functional behavior of a cellular population, our system adds a dimension to blood cell analysis and other measurements of single-cell variability.

  15. [Tissue oxygen saturation in the critically ill patient].

    Science.gov (United States)

    Gruartmoner, G; Mesquida, J; Baigorri, F

    2014-05-01

    Hemodynamic resuscitation seeks to correct global macrocirculatory parameters of pressure and flow. However, current evidence has shown that despite the normalization of these global parameters, microcirculatory and regional perfusion alterations can persist, and these alterations have been independently associated with a poorer patient prognosis. This in turn has lead to growing interest in new technologies for exploring regional circulation and microcirculation. Near infra-red spectroscopy allows us to monitor tissue oxygen saturation, and has been proposed as a noninvasive, continuous and easy-to-obtain measure of regional circulation. The present review aims to summarize the existing evidence on near infra-red spectroscopy and its potential clinical role in the resuscitation of critically ill patients in shock. Copyright © 2013 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  16. 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

  17. 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...... patients with diagnosed PDR were included. We performed wide-field fluorescein angiography (WFA) (Optomap; Optos PLC., Dunfermline, Scotland, UK) and retinal oximetry (Oxymap model T1; Oxymap, software version 2.4.2, Reykjavik, Iceland) at baseline and three months after PRP by a navigated laser (NAVILAS...

  18. Comparison of oxygen saturation values and measurement times by pulse oximetry in various parts of the body.

    Science.gov (United States)

    Yönt, Gülendam Hakverdioğlu; Korhan, Esra Akin; Khorshid, Leyla

    2011-11-01

    The aim of this study, which included 40 patients, was to compare the values pulse oximetry and the measurement times in various regions of the body. Data were analyzed using intraclass correlation coefficient test and paired-sample test. The confidence power value was found to be .81 for the comparison of oxygen saturation values by arterial blood gas analysis and measurement by the forehead probe. It was found that the time for oxygen saturation measurement using the forehead probe was shorter than those using the finger and toe probes. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Nocturnal oxygen saturation profiles of healthy term infants.

    Science.gov (United States)

    Terrill, Philip Ian; Dakin, Carolyn; Hughes, Ian; Yuill, Maggie; Parsley, Chloe

    2015-01-01

    Pulse oximetry is used extensively in hospital and home settings to measure arterial oxygen saturation (SpO2). Interpretation of the trend and range of SpO2 values observed in infants is currently limited by a lack of reference ranges using current devices, and may be augmented by development of cumulative frequency (CF) reference-curves. This study aims to provide reference oxygen saturation values from a prospective longitudinal cohort of healthy infants. Prospective longitudinal cohort study. Sleep-laboratory. 34 healthy term infants were enrolled, and studied at 2 weeks, 3, 6, 12 and 24 months of age (N=30, 25, 27, 26, 20, respectively). Full overnight polysomnography, including 2 s averaging pulse oximetry (Masimo Radical). Summary SpO2 statistics (mean, median, 5th and 10th percentiles) and SpO2 CF plots were calculated for each recording. CF reference-curves were then generated for each study age. Analyses were repeated with sleep-state stratifications and inclusion of manual artefact removal. Median nocturnal SpO2 values ranged between 98% and 99% over the first 2 years of life and the CF reference-curves shift right by 1% between 2 weeks and 3 months. CF reference-curves did not change with manual artefact removal during sleep and did not vary between rapid eye movement (REM) and non-REM sleep. Manual artefact removal did significantly change summary statistics and CF reference-curves during wake. SpO2 CF curves provide an intuitive visual tool for evaluating whether an individual's nocturnal SpO2 distribution falls within the range of healthy age-matched infants, thereby complementing summary statistics in the interpretation of extended oximetry recordings in infants. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  20. Compliance in oxygen saturation targeting in preterm infants : a systematic review

    NARCIS (Netherlands)

    van Zanten, Henriëtte A; Tan, Ratna N G B; van den Hoogen, Agnes; Lopriore, Enrico; te Pas, Arjan B

    2015-01-01

    UNLABELLED: During oxygen therapy in preterm infants, targeting oxygen saturation is important for avoiding hypoxaemia and hyperoxaemia, but this can be very difficult and challenging for neonatal nurses. We systematically reviewed the qualitative and quantitative studies investigating the

  1. [Near-infrared spectroscopy in sepsis therapy : predictor of a low central venous oxygen saturation].

    Science.gov (United States)

    Lichtenstern, C; Koch, C; Röhrig, R; Rosengarten, B; Henrich, M; Weigand, M A

    2012-10-01

    Early goal-directed hemodynamic optimization has become a cornerstone of sepsis therapy. One major defined goal is to achieve adequate central venous oxygen saturation (SO(2)). This study aimed to investigate the correlation between central venous SO(2) and frontal cerebral near-infrared spectroscopy (NIRS) measurement in patients with severe sepsis and septic shock. The NIRS method provides non-invasive measurement of regional oxygen saturation (rSO(2)) in tissues approximately 2 cm below the optical NIRS sensors which depends on arterial, capillary and venous blood. Thus this system gives site-specific real-time data about the balance of oxygen supply and demand. This was a secondary analysis from a prospective study of surgical intensive care (ICU) patients in the early phase of severe sepsis or septic shock. Bilateral cerebral rSO(2), central venous SO(2), arterial oxygen saturation (S(a)O(2)) and other surrogate parameters of oxygen supply, such as hemoglobin, partial pressure of oxygen and oxygen content in arterial blood were recorded. A total of 16 ICU patients (4 women, median age 65.5 years) were included in the study. As sepsis focus an intra-abdominal infection was detected in 62.5 % of patients, severe pneumonia was determined in 31.3 % and skin and soft tissue infections were recognized in 12.5 %. At study inclusion 50 % of patients had septic shock, the median sequential organ failure assessment (SOFA) score was 10.2 (interquartile range 5.25-8.75) and the median acute physiology and chronic health evaluation II (APACHE II) score was 26 (range 23.25-29.75). Mortality at day 28 was 37.5 %. Minimum rSO(2) (median 58) and right-sided rSO(2) (median 58) values showed a significant correlation in the analysis of receiver operating characteristics (area under the curve 0.844, p= 0.045). A central venous SO(2)< 70 % was indicated by rSO(2)< 56.5 with sensitivity and specificity of 75 % and 100 %, respectively. Cerebral NIRS could provide a fast and easily

  2. 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

  3. [Sedation with intravenous midazolam during upper gastrointestinal endoscopy--changes in hemodynamics, oxygen saturation and memory].

    Science.gov (United States)

    Mizuno, Ju; Matsuki, Michiko; Gouda, Yoshinori; Nishiyama, Tomoki; Hanaoka, Kazuo

    2003-09-01

    Cardiorespiratory adverse effects are often observed in patients undergoing upper gastrointestinal endoscopy with sedation. In this study, we examined hemodynamics, oxygen saturation and memory during upper gastrointestinal endoscopy under sedation with intravenous midazolam. Eight healthy outpatients without any obvious complications received intravenous midazolam 5 mg for sedation for upper gastrointestinal endoscopy. Blood pressure, heart rate and percutaneous arterial oxygen saturation (SpO2) were measured before, during and after endoscopy. After the arousal by intravenous flumazenil, we inquired the patients about the level of memory during the endoscopy. Blood pressure decreased significantly two minutes after midazolam administration, but increased significantly after the insertion of an endoscope which was not different from the control value. Heart rate increased significantly one and three minutes after the insertion of the endoscope. SpO2 decreased significantly after midazolam administration and stayed at around 95%. No patients remembered the procedure. Sedation with intravenous midazolam during upper gastrointestinal endoscopy is useful to control the cardiovascular responses, and to obtain amnesia. However, a decrease in SpO2 should be watched carefully.

  4. Blood conservation with membrane oxygenators and dipyridamole.

    Science.gov (United States)

    Teoh, K H; Christakis, G T; Weisel, R D; Madonik, M M; Ivanov, J; Wong, P Y; Mee, A V; Levitt, D; Benak, A; Reilly, P

    1987-07-01

    Cardiopulmonary bypass induces platelet activation and dysfunction, which result in platelet deposition and depletion. Reduced platelet numbers and abnormal platelet function may contribute to postoperative bleeding. A membrane oxygenator may preserve platelets and reduce bleeding more than a bubble oxygenator, and the antiplatelet agent dipyridamole may protect platelets intraoperatively and reduce bleeding postoperatively. A prospective randomized trial was performed in 44 patients undergoing elective coronary artery bypass grafting to assess the effects of the membrane oxygenator and dipyridamole on platelet counts, platelet activation products, and postoperative bleeding. Patients who were randomized to receive a bubble oxygenator and no dipyridamole had the lowest postoperative platelet counts, the greatest blood loss, and the most blood products transfused. Platelet counts were highest and blood loss was least in patients randomized to receive a membrane oxygenator and dipyridamole (p less than .05). A bubble oxygenator with dipyridamole and a membrane oxygenator without dipyridamole resulted in intermediate postoperative platelet counts and blood loss. Arterial thromboxane B2 and platelet factor 4 concentrations were elevated on cardiopulmonary bypass in all groups. Both the membrane oxygenator and dipyridamole were independently effective (by multivariate analysis) in preserving platelets. Optimal blood conservation was achieved with a membrane oxygenator and dipyridamole.

  5. Assessment of oxygen saturation in dental pulp of permanent teeth with periodontal disease.

    Science.gov (United States)

    Giovanella, Larissa Bergesch; Barletta, Fernando Branco; Felippe, Wilson Tadeu; Bruno, Kely Firmino; de Alencar, Ana Helena Gonçalves; Estrela, Carlos

    2014-12-01

    In individuals with periodontal disease, dental pulp status should be determined before a treatment plan is made. Pulse oximeters are promising diagnostic tools to evaluate pulp vascularization. This study used pulse oximetry to determine the level of oxygen saturation in dental pulp of intact permanent teeth with periodontal attachment loss (PAL) and gingival recession (GR) and to evaluate the correlation between periodontal disease and level of oxygen saturation in the pulp. This study included 67 anterior teeth of 35 patients; all teeth showed intact crowns, PAL, a periodontal pocket (PP), and GR. The teeth underwent periodontal examination, cold and electric pulp testing, and pulse oximetry measurements. The Pearson correlation coefficient and a linear regression coefficient were calculated to evaluate the degree of correlation between periodontal disease markers (PAL, PP, and GR) and the level of oxygen saturation in dental pulp. These tests also evaluated possible associations between oxygen saturation and cold and electric pulp testing. PAL, PP, and GR had negative correlations with oxygen saturation in dental pulp. Conversely, no statistically significant association was found between oxygen saturation in dental pulp and the response to electric sensibility testing. Oxygen saturation was lower in the pulp of permanent teeth with PAL, PP, and GR, indicating that periodontal disease correlates with the level of oxygen saturation in the pulp. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  6. [Regional cerebral oxygen saturation as a marker of hemodynamic state following cardiac surgery].

    Science.gov (United States)

    García-Hernández, J A; Aldemira-Liz, A; Martínez-López, A I; Cayuela, A; Charlo-Molina, M T; Cano-Franco, J; Loscertales-Abril, M

    2013-10-01

    Regional cerebral oxygen saturation (rSO₂) is a measure of the general state of perfusion and oxygenation. We aim to analyze the relationship between this and various hemodynamic and respiratory parameters. Forty-three patients, operated on between October 2011 and July 2012, were included in this prospective observational descriptive study. The following parameters were measured: mean arterial pressure, both arterial and central venous oxygen saturation and partial pressures of oxygen and carbon dioxide, and lactate levels. From these parameters, the oxygenation index and the oxygen extraction ratio were calculated. These measurements were studied to evaluate whether rSO₂ correlated significantly with the other parameters. The average age and weight of the patients were 27.3 months and 9.2 kg, respectively. The rSO₂ correlated positively with both central venous oxygen saturation (r=0.73, P 0.4) between the rSO₂ and central venous oxygen saturation, and between the rSO₂ and oxygen extraction ratio. Regional cerebral oxygen saturation correlates well with hemodynamic parameters - mean arterial pressure, venous saturation, and the tissue oxygen extraction. However, it does not correlate with respiratory parameters. Copyright © 2012 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  7. 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...

  8. Comparison of oxygen saturation values obtained from fingers on physically restrained or unrestrained sides of the body.

    Science.gov (United States)

    Korhan, Esra Akin; Yönt, Gülendam Hakverdioğlu; Khorshid, Leyla

    2011-01-01

    The aim of this study was to compare semiexperimentally the pulse oximetry values obtained from a finger on restrained or unrestrained sides of the body. The pulse oximeter provides a noninvasive measurement of the oxygen saturation of hemoglobin in arterial blood. One of the procedures most frequently applied to patients in intensive care units is the application of physical restraint. Circulation problems are the most important complication in patients who are physically restrained. Evaluation of oxygen saturation from body parts in which circulation is impeded or has deteriorated can cause false results. The research sample consisted of 30 hospitalized patients who participated in the study voluntarily and who were concordant with the inclusion criteria of the study. Patient information and patient follow-up forms were used for data collection. Pulse oximetry values were measured simultaneously using OxiMax Nellcor finger sensors from fingers on the restrained and unrestrained sides of the body. Numeric and percentile distributions were used in evaluating the sociodemographic properties of patients. A significant difference was found between the oxygen saturation values obtained from a finger of an arm that had been physically restrained and a finger of an arm that had not been physically restrained. The mean oxygen saturation value measured from a finger of an arm that had been physically restrained was found to be 93.40 (SD, 2.97), and the mean oxygen saturation value measured from a finger of an arm that had not been physically restrained was found to be 95.53 (SD, 2.38). The results of this study indicate that nurses should use a finger of an arm that is not physically restrained when evaluating oxygen saturation values to evaluate them correctly.

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

    Directory of Open Access Journals (Sweden)

    Krishna P. Shetty

    2016-03-01

    Full Text Available 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.

  10. High or low oxygen saturation and severe retinopathy of prematurity: a meta-analysis.

    Science.gov (United States)

    Chen, Minghua L; Guo, Lei; Smith, Lois E H; Dammann, Christiane E L; Dammann, Olaf

    2010-06-01

    Low oxygen saturation appears to decrease the risk of severe retinopathy of prematurity (ROP) in preterm newborns when administered during the first few weeks after birth. High oxygen saturation seems to reduce the risk at later postmenstrual ages (PMAs). However, previous clinical studies are not conclusive individually. To perform a systematic review and meta-analysis to report the association between severe ROP incidence of premature infants with high or low target oxygen saturation measured by pulse oximetry. Studies were identified through PubMed and Embase literature searches through May 2009 by using the terms "retinopathy of prematurity and oxygen" or "retinopathy of prematurity and oxygen therapy." We selected 10 publications addressing the association between severe ROP and target oxygen saturation measured by pulse oximetry. Using a random-effects model we calculated the summary-effect estimate. We visually inspected funnel plots to examine possible publication bias. Low oxygen saturation (70%-96%) in the first several postnatal weeks was associated with a reduced risk of severe ROP (risk ratio [RR]: 0.48 [95% confidence interval (CI): 0.31-0.75]). High oxygen saturation (94%-99%) at > or = 32 weeks' PMA was associated with a decreased risk for progression to severe ROP (RR: 0.54 [95% CI: 0.35-0.82]). Among preterm infants with a gestational age of large randomized clinical trial with long-term developmental follow-up is warranted to confirm this meta-analytic result.

  11. EFFECTIVENESS OF AUTOGENIC DRAINAGE VERSUS POSTURAL DRAINAGE ON OXYGEN SATURATION IN PATIENTS WITH CHRONIC BRONCHITIS WITH 15 MINUTES POST THERAPY

    OpenAIRE

    V. Kiran; Dr. Bhimasen .S; E. Mastanaiah; A. Thiruppathi

    2014-01-01

    Background: Patients with COPD will have more amount of secretions. To clear the secretions by using of different bronchial hygiene techniques like postural drainage and autogenic drainage technique, manual hyperventilation technique ,active cycle breathing technique .Hence in this study to compare the short-term effects of postural drainage with clapping (PD) and autogenic drainage (AD) on level of oxygen saturation in blood, and amount of sputum recovery. Methodology: The study was done ...

  12. 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.

  13. The effect of tourniquet deflation on hemodynamics and regional cerebral oxygen saturation in aged patients undergoing total knee replacement surgery.

    Science.gov (United States)

    Song, Inkyung; Kim, Dong Yeon; Kim, Youn Jin

    2012-11-01

    Inflation and deflation of a pneumatic tourniquet used in total knee replacement surgery induces various changes in patient's hemodynamic and metabolic status, which may result in serious complications, especially in aged patients. Near-infrared spectroscopy (NIRS) is a monitoring device designed to estimate the regional cerebral oxygen saturation. We evaluated the effect of tourniquet deflation on hemodynamics and regional cerebral oxygen saturation in aged patients undergoing total knee replacement surgery, using NIRS. Twenty-eight American Society of Anesthesiologists physical status I or II patients, over the age of sixty-five years undergoing total knee replacement surgery, were included. Under general anesthesia, the mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), stroke volume (SV), and regional cerebral oxygen saturation (rSO(2)) were recorded before induction of anesthesia and every 2 min after tourniquet deflation for 20 min. Arterial blood gas analysis was performed 5 min before, in addition to 0, and 10 min after tourniquet deflation. The decrease of rSO(2) was not significant during 20-min deflation period. MAP, CO and SV showed significant decrease during 2 to 12, 4 to 6 and 2 to 6-min period after tourniquet deflation, respectively (P deflation caused significant changes in hemodynamic and metabolic status, but not in regional cerebral oxygen saturation. It is recommended to monitor neurologic status, as well as hemodynamic and metabolic status to avoid serious complications, especially in aged patients.

  14. Macular Retinal Vessel Oxygen Saturation Elevation in Chinese Central Serous Chorioretinopathy

    Directory of Open Access Journals (Sweden)

    Cheng Li

    2017-01-01

    Full Text Available Purpose. To evaluate the retinal vessel oxygen saturation in central serous chorioretinopathy (CSC cases among the Chinese. Methods. Relative oxygen saturation of retinal blood vessels was measured in 33 Chinese patients with single-eye CSC using the Oxymap T1 retinal oximeter. The contralateral eyes were the control. The mean saturation of the retinal arteriole (AS and venule (VS, arteriovenous difference (AVS, and arteriole and venule diameters (AD, VD was analyzed in the optic disc area and macular region. Results. In the optic disc area, the inferotemporal quadrant (TI AS (93.2 ± 10.2% and inferonasal quadrant (NI VS (61.3 ± 7.3% were higher in the affected eyes than in the contralateral eyes (88.7 ± 7.7% and 56.9 ± 6.5% and AVS in NI (36.7 ± 10.4% decreased compared to the contralateral eyes (41.5 ± 11.2%. The VD in TI was expanded (19.9 ± 2.5 pixels versus 18.1 ± 3.4 pixels. Around the macular region, AS was 93.6 ± 7.6%, higher than in the contralateral eyes (89.5 ± 6.3%. No other significant changes were found. Conclusions. AS increased in the TI, and VS decreased in the NI in the eyes with CSC. In addition, AS also increased around the macular region, suggesting that these are contributors to CSC pathophysiology.

  15. 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

  16. 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.

  17. Oxygen Saturation in the Dental Pulp of Maxillary Premolars in Different Age Groups - Part 1.

    Science.gov (United States)

    Estrela, Carlos; Serpa, Giuliano C; Alencar, Ana Helena G; Bruno, Kely F; Barletta, Fernando B; Felippe, Wilson T; Estrela, Cyntia R A; Souza, João B

    2017-01-01

    The aim of this study was to determine oxygen saturation levels in the dental pulp of maxillary premolars in different age groups. A total of 120 human maxillary premolars with normal dental pulps were selected covering the following age groups: 20-24, 25-29, 30-34, 35-39 and 40-44 years (n=24 each group). Oxygen saturation was assessed using pulse oximetry. Analysis of variance was used to assess differences in oxygen saturation levels and Tukey's test was used to identify the age groups that differed from each other. Significance was set at 0.05. Mean oxygen saturation of 120 premolars was 86.20% considering all age groups. Significantly reduced levels were found in the oldest group compared to the other groups: 40 to 44 years - 80.00% vs. 89.71, 87.67, 88.71, and 84.80% for age groups 20-24, 25-29, 30-34, 35-39 years, respectively. The mean oxygen saturation levels were similar between 20 and 39 years of age (86.20%) in the whole sample, but reduced significantly in the 40-44-year age group, suggesting that older patients present lower oxygen saturation results even in the absence of pulp tissue injury.

  18. 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...

  19. Evaluation of arterial oxygen saturation using RGB camera-based remote photoplethysmography

    Science.gov (United States)

    Nishidate, Izumi; Nakano, Kazuya; McDuff, Daniel; Niizeki, Kyuichi; Aizu, Yoshihisa; Haneishi, Hideaki

    2018-02-01

    Plethysmogram is the periodic variation in blood volume due to the cardiac pulse traveling through the body. Photo-plethysmograph (PPG) has been widely used to assess the cardiovascular system such as heart rate, blood pressure, cardiac output, vascular compliance. We have previously proposed a non-contact PPG imaging method using a digital red-green-blue camera. In the method, the Monte Carlo simulation for light transport is used to specify a relationship among the RGB-values and the concentrations of oxygenated hemoglobin (CHbO) and deoxygenated hemoglobin (CHbR). The total hemoglobin concentration (CHbT) can be calculated as a sum of CHbO and CHbR. Applying the fast Fourier transform (FFT) band pass filters to each pixel of the sequential images for CHbT along the time line, two-dimentional plethysmogram can be reconstructed. In this study, we further extend the method to imaging the arterial oxygen saturation (SaO2). The PPG signals for both CHbO and CHbR are extracted by the FFT band pass filter and the pulse wave amplitudes (PWAs) of CHbO and CHbR are calculated. We assume that the PWA for CHbO and that for CHbR are decreased and increased as SaO2 is decreased. The ratio of PWA for CHbO and that for CHbR are associated to the reference value of SaO2 measured by a commercially available pulse oximeter, which provide an empirical formula to estimate SaO2 from the PPG signal at each pixel of RGB image. In vivo animal experiments with rats during varying the fraction of inspired oxygen (FiO2) demonstrated the feasibility of the proposed method.

  20. Oxygen saturation in children with and without obstructive sleep apnea using the phone-oximeter.

    Science.gov (United States)

    Garde, Ainara; Karlen, Walter; Dehkordi, Parastoo; Wensley, David; Ansermino, J Mark; Dumont, Guy A

    2013-01-01

    Obstructive sleep apnea (OSA) in children can lead to daytime sleepiness, growth failure and developmental delay. Polysomnography (PSG), the gold standard to diagnose OSA is highly resource intensive and is confined to the sleep laboratory. In this study we propose to identify children with OSA using blood oxygen saturation (SpO2) obtained from the Phone Oximeter. This portable, in-home device is able to monitor patients over multiple nights, causes less sleep disturbance and facilitates a more natural sleep pattern. The proposed algorithm analyzes the SpO2 signal in the time and frequency domain using a 90-s sliding window. Three spectral parameters are calculated from the power spectral density (PSD) to evaluate the modulation in the SpO2 due to the oxyhemoblobin desaturations. The power P, slope S in the discriminant band (DB), and ratio R between P and total power are calculated for each window. Tendency and variability indices, number of SpO2 desaturations and time spent under 2% or 3% of baseline saturation level are computed for each time window. The statistical distribution of the temporal evolution of all parameters is analyzed to identify 68 children, 30 with OSA and 38 without OSA (nonOSA). This characterization was evaluated by a feature selection based on a linear discriminant. The combination of temporal and spectral parameters provided the best leave one out crossvalidation results with an accuracy of 86.8%, a sensitivity of 80.0%, and a specificity of 92.1% using only 5 parameters. The median of R, mean of P and S and mean and standard deviation of the number of desaturations below 3% of baseline saturation level, were the most representative parameters. Hence, a better knowledge of SpO2 dynamics could help identifying children with OSA with the Phone Oximeter.

  1. Prognostic value of cerebral tissue oxygen saturation during neonatal extracorporeal membrane oxygenation.

    Directory of Open Access Journals (Sweden)

    Marie-Philippine Clair

    Full Text Available Extracorporeal membrane oxygenation support is indicated in severe and refractory respiratory or circulatory failures. Neurological complications are typically represented by acute ischemic or hemorrhagic lesions, which induce higher morbidity and mortality. The primary goal of this study was to assess the prognostic value of cerebral tissue oxygen saturation (StcO2 on mortality in neonates and young infants treated with ECMO. A secondary objective was to evaluate the association between StcO2 and the occurrence of cerebral lesions.This was a prospective study in infants < 3 months of age admitted to a pediatric intensive care unit and requiring ECMO support.The assessment of cerebral perfusion was made by continuous StcO2 monitoring using near-infrared spectroscopy (NIRS sensors placed on the two temporo-parietal regions. Neurological lesions were identified by MRI or transfontanellar echography.Thirty-four infants <3 months of age were included in the study over a period of 18 months. The ECMO duration was 10±7 days. The survival rate was 50% (17/34 patients, and the proportion of brain injuries was 20% (7/34 patients. The mean StcO2 during ECMO in the non-survivors was reduced in both hemispheres (p = 0.0008 right, p = 0.03 left compared to the survivors. StcO2 was also reduced in deceased or brain-injured patients compared to the survivors without brain injury (p = 0.002.StcO2 appears to be a strong prognostic factor of survival and of the presence of cerebral lesions in young infants during ECMO.

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

    Science.gov (United States)

    Abel, Gemma; Allen, John; Drinnan, Michael

    2014-09-01

    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.

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

    International Nuclear Information System (INIS)

    Abel, Gemma; Allen, John; Drinnan, Michael

    2014-01-01

    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)

  4. Effects of spinal immobilization at a 20° angle on cerebral oxygen saturations measured by INVOS™.

    Science.gov (United States)

    Aksel, Gökhan

    2018-01-01

    In this study, we aimed to investigate whether performing the immobilization at 20° instead of 0° changes cerebral oxygenation. 33 volunteers were put in a hard cervical collar and backboard at 0° and immobilized for 30min. The cerebral oxygen saturations of the volunteers were measured at 1, 5, and 30min after the start of the procedure (Group 1). The volunteers were asked to return the day after the Group 1 procedure but at the same time. Serial cerebral oxygen saturations were obtained at the same time intervals as in Group 1, but for Group 2, the backboard was set to 20°. When the cerebral oxygen saturations of the two groups were compared, there was a slight decrease when the backboard position was changed from 0° to 20°, but it was not statistically significant (P=0.220 and P=0.768, respectively). The results revealed that immobilizing the patients with a spinal backboard at 20° instead of 0° did not alter the cerebral oxygen saturations. Our study results revealed that spinal immobilization at 20°, which was a new suggestion for spinal immobilization following a report that this position reduced the decrease in pulmonary function secondary to spinal immobilization, did not alter the cerebral oxygenation, so this suggestion is safe at least from the standpoint of cerebral oxygenation. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. 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.

  6. 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.

  7. Lower early postnatal oxygen saturation target and risk of ductus arteriosus closure failure.

    Science.gov (United States)

    Inomata, Kei; Taniguchi, Shinji; Yonemoto, Hiroki; Inoue, Takeshi; Kawase, Akihiko; Kondo, Yuichi

    2016-11-01

    Early postnatal hyperoxia is a major risk factor for retinopathy of prematurity (ROP) in extremely premature infants. To reduce the occurrence of ROP, we adopted a lower early postnatal oxygen saturation (SpO 2 ) target range (85-92%) from April 2011. Lower SpO 2 target range, however, may lead to hypoxemia and an increase in the risk of ductus arteriosus (DA) closure failure. The aim of this study was therefore to determine whether a lower SpO 2 target range, during the early postnatal stage, increases the risk of DA closure failure. Infants born at closure failure in period 2 (21%) was significantly higher than that in period 1 (1%). On multivariate logistic regression analysis, the lower oxygen saturation target range was an independent risk factor for DA closure failure. Lower early postnatal oxygen saturation target range increases the risk of DA closure failure. © 2016 Japan Pediatric Society.

  8. Retinal oxygen saturation in relation to retinal thickness in diabetic macular edema

    DEFF Research Database (Denmark)

    Blindbæk, Søren Leer; Peto, Tunde; Grauslund, Jakob

    to retinal thickness in patients with diabetic macular edema (DME). Methods: We included 18 patients with DME that all had central retinal thickness (CRT) >300 µm and were free of active proliferative diabetic retinopathy. Optical coherence tomography (Topcon 3D OCT-2000 spectral domain OCT) was used...... for paracentral edema, the oxygen saturation in the upper and lower temporal arcade branches were compared to the corresponding upper and lower subfield thickness. Spearman’s rank was used to calculate correlation coefficients between CRT and retinal oximetry. Results: Median age and duration of diabetes was 59....... 92.3%, p=0.52). We found no correlation between CRT and retinal oxygen saturation, even when accounting for paracentral edema (p>0.05). Furthermore, there was no difference in retinal oxygen saturation between the macular hemisphere that was more or less affected by DME (p>0.05). Conclusion: Patients...

  9. Detection of cerebral arterial gas embolism using regional cerebral oxygen saturation, quantitative electroencephalography, and brain oxygen tension in the swine

    NARCIS (Netherlands)

    Weenink, R. P.; Hollmann, M. W.; Stevens, M. F.; Kager, J.; van Gulik, T. M.; van Hulst, R. A.

    2014-01-01

    Cerebral air emboli occur as a complication of invasive medical procedures. The sensitivity of cerebral monitoring methods for the detection of air emboli is not known. This study investigates the utility of electroencephalography and non-invasively measured cerebral oxygen saturation in the

  10. Sodium addition and/or oxygen saturation of iohexol during normal and reduced perfusion pressure

    International Nuclear Information System (INIS)

    Baath, L.

    1990-01-01

    The influence on contractile force (CF) and the propensity for ventricular fibrillation (VF) from infusing the non-ionic contrast medium iohexol during normal (75 cm H 2 O) and reduced perfusion pressure (35 cm H 2 O) were investigated in the isolated rabbit heart. Both during normal and reduced perfusion pressure iohexol (150 mg I/ml) with oxygen saturation caused a smaller reduction of CF than iohexol without oxygen. During reduced pressure iohexol with sodium addition (28 mM NaCl) caused less depression of CF than iohexol without sodium. The combination of sodium addition and oxygen saturation had the least influence on CF. Iohexol (350 mg I/ml) without sodium had a similar fibrillatory propensity during both normal and reduced pressure. Enriching iohexol with 28 mM NaCl decreased the risk of VF. The decrease was similar during both normal and reduced pressure. The risk of VF from oxygen saturation of iohexol (350 mg I/ml, without sodium) was similar during both normal and reduced pressure. It is concluded that a small addition of sodium and/or oxygen saturation of a non-ionic monomeric contrast medium have beneficial effects on the heart both during normal perfusion pressure and during ischemia. (orig.)

  11. Cerebral blood flow and oxygen metabolism after subarachnoid hemorrhage

    International Nuclear Information System (INIS)

    Ito, Hidemichi; Sakurai, Takashi; Hayashi, Tatsuo; Hashimoto, Takuo

    2004-01-01

    The mechanism of reduction of cerebral circulation in the early phase of aneurysmal subarachnoid hemorrhage (SAH) has not yet been clarified. Previous studies have variously indicated that cerebral blood flow (CBF) reduction may be due to cerebral vasospasm, an elevation in intracranial pressure (ICP), constriction of intraparenchymal arterioles, or metabolic reduction. The aim of this study is to investigate the relationship between cerebral circulation and oxygen metabolism. In 36 patients with aneurysmal SAH, the values of mean cerebral blood flow (mCBF), cerebral metabolic rate of oxygen (GMRO 2 ) and oxygen extraction fraction (OEF) were measured by using single photon emission computed tomography (SPECT) with arterial blood drawing and oxygen saturation of internal jugular bulb blood (SjO 2 ) in the acute stage (1-3 days after onset) and the spasm stage (7-10 days after onset). The patients in our study were selected by using the following criteria: no history of cerebrovascular or cardiopulmonary diseases; under the age of 70; the ruptured aneurysm was treated by clipping or coil embolization within 72 hours after onset; no symptoms of cerebral vasospasm; no signs of cerebral ischemic change on CT scans. These patients were divided into 2 groups according to the World Federation of Neurological Surgeons (WFNS) grading classification; the mild group (Grades I and II) consisted of 27 cases and the severe group (Grade IV) consisted of 9 cases. We studied differences in mCBF CMRO 2 , and OEF between the mild group and severe group. In the mild group, mCBF, CMRO 2 , and OEF were significantly higher than in the severe group during both the acute and the spasm stage. Also mCBF showed a direct correlation with CMRO 2 . All the patients were kept under the following conditions: the bed was positioned so that the upper body was raised at an angle at 30 deg; blood pressure was maintained at 130-150 mmHg and PaCO 2 of arterial blood was maintained at 35-40 mmHg; ICP

  12. Lack of differences in the regional variation of oxygen saturation in larger retinal vessels in diabetic maculopathy and proliferative diabetic retinopathy.

    Science.gov (United States)

    Jørgensen, Christina Mørup; Bek, Toke

    2017-06-01

    Diabetic retinopathy is characterised by morphological lesions in the ocular fundus related to disturbances in retinal blood flow. The two vision threatening forms of retinopathy show specific patterns of distribution of retinal lesions with proliferative diabetic retinopathy (PDR) developing secondary to ischaemia and hypoxia in the retinal periphery and diabetic maculopathy (DM) developing secondary to hyperperfusion and increased vascular permeability in the macular area. These differences in the distribution of retinal lesions might be reflected in regional differences in oxygen saturation in the larger retinal vessels. Dual-wavelength retinal oximetry was performed in 30 normal persons, 30 patients with DM and 30 patients with PDR, and the oxygen saturation was measured in peripapillary vessels supplying the four retinal quadrants and in branches from the upper temporal arcades supplying, respectively, the macular area and the retinal periphery. The overall oxygen saturation was significantly higher in diabetic patients than in normal persons and the arteriovenous (AV) saturation difference significantly lower in the patients with DM. The regional variation in oxygen saturation was similar in the three studied groups with a decreasing saturation from the upper nasal through the lower nasal, lower temporal and the upper temporal peripapillary vessels, and with a significantly higher oxygen saturation in venules draining the macular area than in venules draining the retinal periphery. The regional differences in retinal lesions in vision threatening diabetic retinopathy are not reflected in regional differences in the oxygen saturation of larger retinal vessels. The development of vision threatening diabetic retinopathy depends on other factors, such as, for example, regional differences in the retinal microcirculation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

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

    Science.gov (United States)

    Kusku, Aysegul; Demir, Guray; Cukurova, Zafer; Eren, Gulay; Hergunsel, Oya

    2014-01-01

    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. 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 (15mg 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 60min. Pre- and postoperative haemoglobin levels were measured. The variations in data obtained and their correlations with the cerebral oxygen levels were investigated. 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. 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 not result in deterioration of cognitive functioning

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

    Science.gov (United States)

    Kusku, Aysegul; Demir, Guray; Cukurova, Zafer; Eren, Gulay; Hergunsel, Oya

    2014-01-01

    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. 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 (15mg 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 60min. Pre- and postoperative haemoglobin levels were measured. The variations in data obtained and their correlations with the cerebral oxygen levels were investigated. 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. 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 not result in deterioration of cognitive functioning

  15. Changes in retinal oxygen saturation after intravitreal aflibercept in patients with diabetic macular edema

    DEFF Research Database (Denmark)

    Blindbæk, Søren Leer; Peto, Tunde; Grauslund, Jakob

    2017-01-01

    Design of study: Three months prospective interventional study. Purpose: To evaluate changes in retinal arterial and venous oxygen saturation after intravitreal aflibercept in patients with diabetic macular edema (DME). Methods: We included 17 patients with DME, central retinal thickness (CRT) >300...

  16. 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.

  17. Reduced deep regional cerebral venous oxygen saturation in hemodialysis patients using quantitative susceptibility mapping.

    Science.gov (United States)

    Chai, Chao; Liu, Saifeng; Fan, Linlin; Liu, Lei; Li, Jinping; Zuo, Chao; Qian, Tianyi; Haacke, E Mark; Shen, Wen; Xia, Shuang

    2018-02-01

    Cerebral venous oxygen saturation (SvO 2 ) is an important indicator of brain function. There was debate about lower cerebral oxygen metabolism in hemodialysis patients and there were no reports about the changes of deep regional cerebral SvO 2 in hemodialysis patients. In this study, we aim to explore the deep regional cerebral SvO 2 from straight sinus using quantitative susceptibility mapping (QSM) and the correlation with clinical risk factors and neuropsychiatric testing . 52 hemodialysis patients and 54 age-and gender-matched healthy controls were enrolled. QSM reconstructed from original phase data of 3.0 T susceptibility-weighted imaging was used to measure the susceptibility of straight sinus. The susceptibility was used to calculate the deep regional cerebral SvO 2 and compare with healthy individuals. Correlation analysis was performed to investigate the correlation between deep regional cerebral SvO 2 , clinical risk factors and neuropsychiatric testing. The deep regional cerebral SvO 2 of hemodialysis patients (72.5 ± 3.7%) was significantly lower than healthy controls (76.0 ± 2.1%) (P deep regional cerebral SvO 2 in patients. The Mini-Mental State Examination (MMSE) scores of hemodialysis patients were significantly lower than healthy controls (P deep regional cerebral SvO 2 did not correlate with MMSE scores (P = 0.630). In summary, the decreased deep regional cerebral SvO 2 occurred in hemodialysis patients and dialysis duration, parathyroid hormone, hematocrit, hemoglobin and red blood cell may be clinical risk factors.

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

    Science.gov (United States)

    Prasetyono, Theddeus O H; Adianto, Senja

    2013-09-01

    The aim of this study was to collect important data on the time of oxygen saturation change in relation to skin flap color alteration using non-invasive pulse oximetry to evaluate its ability to provide continuous monitoring of skin flap perfusion. An experimental study on the monitoring of blood perfusion of 20 tube-island groin flaps of 10 male New Zealand rabbits was performed using pulse oximetry. The animals were randomly assigned to one of two groups representing a blockage of either arterial or venous blood flow. The oxygen saturation change and clinical color alteration were monitored from the beginning of vessel clamping until the saturation became undetectable. The result was analyzed by the t-test using SSPS ver. 10.0. The mean times from the vessel clamping until the saturation became undetectable were 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 clamping was 34.5±11.72 minutes, while the alteration in flaps with artery clamping could not be detected until 2.5 hours after clamping. The use of neonate-type reusable flex sensor-pulse oximetry is objective and effective in early detection of arterial and vein blockage. It provides real-time data on vessel occlusion, which in turn will allow for early salvaging. The detection periods of both arterial occlusion and venous congestion are much earlier than the color alteration one may encounter clinically.

  19. 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 BackgroundThe aim of this study was to collect important data on the time of oxygen saturation change in relation to skin flap color alteration using non-invasive pulse oximetry to evaluate its ability to provide continuous monitoring of skin flap perfusion.MethodsAn experimental study on the monitoring of blood perfusion of 20 tube-island groin flaps of 10 male New Zealand rabbits was performed using pulse oximetry. The animals were randomly assigned to one of two groups representing a blockage of either arterial or venous blood flow. The oxygen saturation change and clinical color alteration were monitored from the beginning of vessel clamping until the saturation became undetectable. The result was analyzed by the t-test using SSPS ver. 10.0.ResultsThe mean times from the vessel clamping until the saturation became undetectable were 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 clamping was 34.5±11.72 minutes, while the alteration in flaps with artery clamping could not be detected until 2.5 hours after clamping.ConclusionsThe use of neonate-type reusable flex sensor-pulse oximetry is objective and effective in early detection of arterial and vein blockage. It provides real-time data on vessel occlusion, which in turn will allow for early salvaging. The detection periods of both arterial occlusion and venous congestion are much earlier than the color alteration one may encounter clinically.

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

    International Nuclear Information System (INIS)

    Vachon, A.; Lecomte, C.; Berleur, F.

    1986-04-01

    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 T 1 and T 2 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 T 2 weakly modified by spin exchange between paramagnetic spin probe and oxygen in triplet state, P1/2 is inversely proportional to T 1 , 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 T 1 (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

  1. 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...... 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. Multimodal...

  2. Hypoxia, Color Vision Deficiencies, and Blood Oxygen Saturation

    Science.gov (United States)

    2013-11-01

    using the Dvorine Pseudoisochromatic Plate Test (2nd edition, Psychological Corporation, Baltimore, MD) illuminated by True Daylight Illuminator T8...Plant, G.T. (1994). Insights into the different exploits of colour in the visual cortex. Proc Biol Sci, 258 (1353), 327-334. Barbur, J.L...Aviat Space Environ Med, 80, 933-940. Crow, T.J.,& Kelman, G.R.(1973). Psychological effects of mild acute hypoxia. Br J Anaesth, 45, 335-337

  3. Hypoxia, color vision deficiencies, and blood oxygen saturation.

    Science.gov (United States)

    2013-11-01

    Chromatic thresholds were measured using the Cambridge Color Test (CCT), Color Assessment and Diagnosis : (CAD) test, and Cone Specific Contrast Test at ground and 3780 m (12,400 ft) for subjects with normal color : vision and red-green color vision ...

  4. Optimization measurement of muscle oxygen saturation under isometric studies using FNIRS

    Science.gov (United States)

    Halim, A. A. A.; Laili, M. H.; Salikin, M. S.; Rusop, M.

    2018-05-01

    Development of functional near infrared spectroscopy (fNIRS) technologies has advanced quantification signal using multiple wavelength and detector to investigate hemodynamic response in human muscle. These non-invasive technologies have been widely used to solve the propagation of light inside the tissues including the absorption, scattering coefficient and to quantify the oxygenation level of haemoglobin and myoglobin in human muscle. The goal of this paper is to optimize the measurement of muscle oxygen saturation during isometric exercise using functional near infrared spectroscopy (fNIRS). The experiment was carried out on 15 sedentary healthy male volunteers. All volunteers are required to perform an isometric exercise at three assessment of muscular fatigue's level on flexor digitalis (FDS) muscle in the human forearm using fNIRS. The slopes of the signals have been highlighted to evaluate the muscle oxygen saturation of regional muscle fatigue. As a result, oxygen saturation slope from 10% exercise showed steeper than the first assessment at 30%-50% of fatigues level. The hemodynamic signal response showed significant value (p=0.04) at all three assessment of muscular fatigue's level which produce a p-value (p<0.05) measured by fNIRS. Thus, this highlighted parameter could be used to estimate fatigue's level of human and could open other possibilities to study muscle performance diagnosis.

  5. Evaluation of different near-infrared spectroscopy technologies for assessment of tissue oxygen saturation during a vascular occlusion test.

    Science.gov (United States)

    Steenhaut, Kevin; Lapage, Koen; Bové, Thierry; De Hert, Stefan; Moerman, Annelies

    2017-12-01

    An increasing number of NIRS devices are used to provide measurements of peripheral tissue oxygen saturation (S t O 2 ). The aim of the present study is to test the hypothesis that despite technological differences between devices, similar trend values will be obtained during a vascular occlusion test. The devices compared are NIRO-200NX, which measures S t O 2 and oxyhemoglobin by spatially resolved spectroscopy and the Beer-Lambert law, respectively, and INVOS 5100C and Foresight Elite, which both measure S t O 2 with the Beer-Lambert law, enhanced with the spatial resolution technique. Forty consenting adults scheduled for CABG surgery were recruited. The respective sensors of the three NIRS devices were applied over the brachioradial muscle. Before induction of anesthesia, 3 min of ischemia were induced by inflating a blood pressure cuff at the upper arm, whereafter cuff pressure was rapidly released. Tissue oxygenation measurements included baseline, minimum and maximum values, desaturation and resaturation slopes, and rise time. Comparisons between devices were performed with the Kruskal-Wallis test with post hoc Mann-Whitney pairwise comparisons. Agreement was evaluated using Bland-Altman plots. Oxyhemoglobin measured with NIRO responded faster than the other NIRS technologies to changes in peripheral tissue oxygenation (20 vs. 27-40 s, p ≤ 0.01). When comparing INVOS with Foresight, oxygenation changes were prompter (upslope 311 [92-523]%/min vs. 114[65-199]%/min, p ≤ 0.01) and more pronounced (minimum value 36 [21-48] vs. 45 [40-51]%, p ≤ 0.01) with INVOS. Significant differences in tissue oxygen saturation measurements were observed, both within the same device as between different devices using the same measurement technology.

  6. 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.

  7. Oxygen breathing accelerates decompression from saturation at 40 msw in 70-kg swine.

    Science.gov (United States)

    Petersen, Kyle; Soutiere, Shawn E; Tucker, Kathryn E; Dainer, Hugh M; Mahon, Richard T

    2010-07-01

    Submarine disaster survivors can be transferred from a disabled submarine at a pressure of 40 meters of seawater (msw) to a new rescue vehicle; however, they face an inherently risky surface interval before recompression and an enormous decompression obligation due to a high likelihood of saturation. The goal was to design a safe decompression protocol using oxygen breathing and a trial-and-error methodology. We hypothesized that depth, timing, and duration of oxygen breathing during decompression from saturation play a role to mitigate decompression outcomes. Yorkshire swine (67-75 kg), compressed to 40 msw for 22 h, underwent one of three accelerated decompression profiles: (1) 13.3 h staged air decompression to 18 msw, followed by 1 h oxygen breathing, then dropout; (2) direct decompression to 18 msw followed by 1 h oxygen breathing then dropout; and (3) 1 h oxygen prebreathe at 40 msw followed by 1 h mixed gas breathing at 26 msw, 1 h oxygen breathing at 18 msw, and 1 h ascent breathing oxygen. Animals underwent 2-h observation for signs of DCS. Profile 1 (14.3 h total) resulted in no deaths, no Type II DCS, and 20% Type I DCS. Profile 2 (2.1 h total) resulted in 13% death, 50% Type II DCS, and 75% Type I DCS. Profile 3 (4.5 h total) resulted in 14% death, 21% Type II DCS, and 57% Type I DCS. No oxygen associated seizures occurred. Profile 1 performed best, shortening decompression with no death or severe DCS, yet it may still exceed emergency operational utility in an actual submarine rescue.

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

    International Nuclear Information System (INIS)

    Quintanar, L.; Stolik, S.; Rosa, J. de la; Moreno, E.

    2012-01-01

    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)

  9. EFFECTIVENESS OF AUTOGENIC DRAINAGE VERSUS POSTURAL DRAINAGE ON OXYGEN SATURATION IN PATIENTS WITH CHRONIC BRONCHITIS WITH 15 MINUTES POST THERAPY

    Directory of Open Access Journals (Sweden)

    V. Kiran

    2014-12-01

    Full Text Available Background: Patients with COPD will have more amount of secretions. To clear the secretions by using of different bronchial hygiene techniques like postural drainage and autogenic drainage technique, manual hyperventilation technique ,active cycle breathing technique .Hence in this study to compare the short-term effects of postural drainage with clapping (PD and autogenic drainage (AD on level of oxygen saturation in blood, and amount of sputum recovery. Methodology: The study was done on 60 patients with COPD. Dividing Patients into two group and patients were treated with PD or AD in separate Groups. The effectiveness of the treatment was measured up to 6 days. Pulse oximetry was monitored and sputum was collected immediately after treatment and 15 minutes following each treatment. Results: The results of the study shown that there was significant difference in the amount of sputum recovered with AD (14.0±3.5 g vs PD (24.4±3.0 g and significant differences in Oxygen saturation; during PD fell from 93.3±0.7% to 91.2±0.8% (p<0.01 and required 15 min following treatment to return to baseline. Oxygen saturation did not fall during AD and increased to gradually following complete treatment days (baseline, 93.3±0.8%; p<0.01. Conclusion: Hence this study concludes that Autogenic drainage is more effective in improving spo2 in COPD & does not cause a sudden fall in spo2 as occurs in Postural drainage immediately after therapy. And it can be better tolerated by patients with COPD while producing fewer benefits in sputum clearance. In concern to mean amount of secretion removal Postural is found to be more effective

  10. Degradation of phospholipids under different types of irradiation and varying oxygen saturation

    Czech Academy of Sciences Publication Activity Database

    Vyšín, Luděk; Tomanová, K.; Pavelková, T.; Wagner, Richard; Davídková, Marie; Múčka, V.; Čuba, V.; Juha, Libor

    2017-01-01

    Roč. 56, č. 3 (2017), s. 241-247 ISSN 0301-634X R&D Projects: GA ČR GA13-28721S; GA ČR(CZ) GBP108/12/G108; GA MŠk LM2015056 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : lipid peroxidation * DOPC * gamma rays * eectrons * protons * oxygen saturation Subject RIV: BO - Biophysics OBOR OECD: Biophysics Impact factor: 2.398, year: 2016

  11. Changes in Oxygen Partial Pressure in the Vitreous Body and Arterial Blood of Rabbits Depending on Oxygen Concentration in Inspired Mixture.

    Science.gov (United States)

    Amkhanitskaya, L I; Nikolaeva, G V; Sokolova, N A

    2015-07-01

    We demonstrated that the vitreous body of one-month-old rabbits becomes a "reservoir" for storage and accumulation of oxygen after exposure to additional oxygenation of the organism (O2 concentrations in inspired gas mixture were 40, 60, 85, and 99%). The higher was O2 concentration in inspired mixture, the higher was oxygen saturation of the blood and vitreous body. O2 concentration of 40% was relatively safe for eye tissues. O2 concentration >60% induced oxygen accumulation in the vitreous body, which can be a provoking factor for the development of oxygen-induced pathologies.

  12. Skin Blood Perfusion and Oxygenation Colour Affect Perceived Human Health

    Science.gov (United States)

    Stephen, Ian D.; Coetzee, Vinet; Law Smith, Miriam; Perrett, David I.

    2009-01-01

    Skin blood perfusion and oxygenation depends upon cardiovascular, hormonal and circulatory health in humans and provides socio-sexual signals of underlying physiology, dominance and reproductive status in some primates. We allowed participants to manipulate colour calibrated facial photographs along empirically-measured oxygenated and deoxygenated blood colour axes both separately and simultaneously, to optimise healthy appearance. Participants increased skin blood colour, particularly oxygenated, above basal levels to optimise healthy appearance. We show, therefore, that skin blood perfusion and oxygenation influence perceived health in a way that may be important to mate choice. PMID:19337378

  13. Monitoring mixed venous oxygen saturation in patients with obstructive shock after massive pulmonary embolism.

    Science.gov (United States)

    Krivec, Bojan; Voga, Gorazd; Podbregar, Matej

    2004-05-31

    Patients with massive pulmonary embolism and obstructive shock usually require hemodynamic stabilization and thrombolysis. Little is known about the optimal and proper use of volume infusion and vasoactive drugs, or about the titration of thrombolytic agents in patients with relative contraindication for such treatment. The aim of the study was to find the most rapidly changing hemodynamic variable to monitor and optimize the treatment of patients with obstructive shock following massive pulmonary embolism. Ten consecutive patients hospitalized in the medical intensive care unit in the community General Hospital with obstructive shock following massive pulmonary embolism were included in the prospective observational study. Heart rate, systolic arterial pressure, central venous pressure, mean pulmonary-artery pressure, cardiac index, total pulmonary vascular-resistance index, mixed venous oxygen saturation, and urine output were measured on admission and at 1, 2, 3, 4, 8, 12, and 16 hours. Patients were treated with urokinase through the distal port of a pulmonary-artery catheter. At 1 hour, mixed venous oxygen saturation, systolic arterial pressure and cardiac index were higher than their admission values (31+/-10 vs. 49+/-12%, p<0.0001; 86+/-12 vs. 105+/-17 mmHg, p<0.01; 1.5+/-0.4 vs. 1.9+/-0.7 L/min/m2, p<0.05; respectively), whereas heart rate, central venous pressure, mean pulmonary-artery pressure and urine output remained unchanged. Total pulmonary vascular-resistance index was lower than at admission (29+/-10 vs. 21+/-12 mmHg/L/min/m2, p<0.05). The relative change of mixed venous oxygen saturation at hour 1 was higher than the relative changes of all other studied variables (p<0.05). Serum lactate on admission and at 12 hours correlated to mixed venous oxygen saturation (r=-0.855, p<0.001). In obstructive shock after massive pulmonary embolism, mixed venous oxygen saturation changes more rapidly than other standard hemodynamic variables.

  14. 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.

  15. The Effect of Non-nutritive Sucking on Transcutaneous Oxygen Saturation in Neonates under the Nasal Continuous Positive Airway Pressure (CPAP

    Directory of Open Access Journals (Sweden)

    Mousa Ahmadpour-kacho

    2017-03-01

    Full Text Available BackgroundSeveral beneficial effects of non-nutritive sucking in infants, including the physiological stability, relaxation, better transition from tube feeding to oral feeding have been reported. But its effect on oxygen saturation in neonates under the Nasal Continuous Positive Airway Pressure (NCPAPو (is not so clear. This study aimed to investigate the effects of non-nutritive sucking on transcutaneous oxygen saturation levels of neonates treated with NCPAP.Materials and MethodsThis quasi-experimental study was done on 25 preterm neonates, hospitalized with a diagnosis of respiratory distress, required NCPAP, in the neonatal intensive care unit (NICU at the Ayatollah Rouhani Hospital and Babol Clinic, North of Iran. Non-nutritive sucking was elicited by a standard pacifier appropriate to their age one hour a day, and the mean oxygen saturation was measured before and after intervention by cardiopulmonary monitoring (Saadat Co., Iran. Data analyzed using SPSS-18.0 software.ResultsIn the 25 cases studied, the mean oxygen saturation values ​​before performing non-nutritive sucking was 96.31±2.88%, which was changed to 98.35±1.6% after intervention, and this increase was statistically significant (P = 0.004.Results showed that the gender, birth weight and gestational age of neonates had no effect on mean Blood oxygen saturation (SpO2level.ConclusionAccording to the results, using the non-nutritive sucking in premature neonates under the NCPAP, can improve oxygenation.

  16. Intelligent Approach for Analysis of Respiratory Signals and Oxygen Saturation in the Sleep Apnea/Hypopnea Syndrome

    Science.gov (United States)

    Moret-Bonillo, Vicente; Alvarez-Estévez, Diego; Fernández-Leal, Angel; Hernández-Pereira, Elena

    2014-01-01

    This work deals with the development of an intelligent approach for clinical decision making in the diagnosis of the Sleep Apnea/Hypopnea Syndrome, SAHS, from the analysis of respiratory signals and oxygen saturation in arterial blood, SaO2. In order to accomplish the task the proposed approach makes use of different artificial intelligence techniques and reasoning processes being able to deal with imprecise data. These reasoning processes are based on fuzzy logic and on temporal analysis of the information. The developed approach also takes into account the possibility of artifacts in the monitored signals. Detection and characterization of signal artifacts allows detection of false positives. Identification of relevant diagnostic patterns and temporal correlation of events is performed through the implementation of temporal constraints. PMID:25035712

  17. Mental abilities and performance efficacy under a simulated 480 meters helium-oxygen saturation diving

    Directory of Open Access Journals (Sweden)

    gonglin ehou

    2015-07-01

    Full Text Available Stress in extreme environment severely disrupts human physiology and mental abilities. The present study investigated the cognition and performance efficacy of four divers during a simulated 480 meters helium-oxygen saturation diving. We analyzed the spatial memory, 2D/3D mental rotation functioning, grip strength, and hand-eye coordination ability in four divers during the 0 – 480 meters compression and decompression processes of the simulated diving. The results showed that except for its mild decrease on grip strength, the high atmosphere pressure condition significantly impaired the hand-eye coordination (especially at 300 meters, the reaction time and correct rate of mental rotation, as well as the spatial memory (especially as 410 meters, showing high individual variability. We conclude that the human cognition and performance efficacy are significantly affected during deep water saturation diving.

  18. 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.

  19. [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.

  20. An efficient optimization method to improve the measuring accuracy of oxygen saturation by using triangular wave optical signal

    Science.gov (United States)

    Li, Gang; Yu, Yue; Zhang, Cui; Lin, Ling

    2017-09-01

    The oxygen saturation is one of the important parameters to evaluate human health. This paper presents an efficient optimization method that can improve the accuracy of oxygen saturation measurement, which employs an optical frequency division triangular wave signal as the excitation signal to obtain dynamic spectrum and calculate oxygen saturation. In comparison to the traditional method measured RMSE (root mean square error) of SpO2 which is 0.1705, this proposed method significantly reduced the measured RMSE which is 0.0965. It is notable that the accuracy of oxygen saturation measurement has been improved significantly. The method can simplify the circuit and bring down the demand of elements. Furthermore, it has a great reference value on improving the signal to noise ratio of other physiological signals.

  1. Efeitos do salbutamol e do formoterol sobre pressão arterial, frequência cardíaca e saturação de oxigénio em asmáticos, durante uma hora One hour effects of salbutamol and formoterol on blood pressure, heart rate and oxygen saturation in asthmatics

    Directory of Open Access Journals (Sweden)

    Geraldo Andrade Capuchinho-Júnior

    2008-06-01

    Full Text Available Objectivo: Analisar os possíveis efeitos do uso de β -2 -agonistas, de curta e longa duração, nas pressões arteriais sistólica (PAS e diastólica (PAD, na saturação parcial de oxigénio (SpO2 e na frequência cardíaca (FC, durante o período de uma hora. Material e métodos: Vinte e quatro doentes com asma persistente grave, em tratamento no ambulatório de Pneumologia do Hospital Universitário Gaffrée e Guinle, foram seleccionados para um ensaio clínico sequencial e cruzado. Os valores da PAS, PAD, SpO2 e FC foram registados antes e após o uso de broncodilatadores, salbutamol 400 µg e formoterol 12 µg, em dias diferentes, com intervalo mínimo de 24 horas. Resultados: Todos os doentes apresentaram distúrbio ventilatório obstrutivo, identificado pela redução da relação entre o volume expiratório forçado no primeiro segundo (VEMS e a capacidade vital forçada (CVF. Após o uso de substância broncodilatadora, não houve variação significativa nas PAS e PAD, nem na FC; porém, a SpO2 aumentou com o uso de salbutamol. Conclusão: Não foram observadas alterações hemodinâmicas significativas após o uso de salbutamol e formoterol nas doses preconizadas.Aim: To analyse systolic (SBP and diastolic blood pressure (DBP, partial oxygen saturation (SpO2 and heart rate (HR disorders for an hour after short and long acting ß2-agonists. Material and methods: Twenty-four severe persistent asthma Pulmonology outpatients at Hospital Universitário Gaffrée e Guinle were selected. SBP, DBP, SpO2 and HR values were determined before and after 400 µg of salbutamol and 12 µg of formoterol, on different days, with a minimum interval of 24 hours. Results: All patients showed ventilatory obstruction, as seen by a reduced FEV1/FVC ratio. There was no statistical SBP/DBP/HR difference after bronchodilator agents, but SpO2 increased with salbutamol. Conclusion: A standard dose of salbutamol and formoterol does not cause haemodynamic

  2. The effect of tourniquet deflation on hemodynamics and regional cerebral oxygen saturation in aged patients undergoing total knee replacement surgery

    OpenAIRE

    Song, Inkyung; Kim, Dong Yeon; Kim, Youn Jin

    2012-01-01

    Background Inflation and deflation of a pneumatic tourniquet used in total knee replacement surgery induces various changes in patient's hemodynamic and metabolic status, which may result in serious complications, especially in aged patients. Near-infrared spectroscopy (NIRS) is a monitoring device designed to estimate the regional cerebral oxygen saturation. We evaluated the effect of tourniquet deflation on hemodynamics and regional cerebral oxygen saturation in aged patients undergoing tot...

  3. Changes in retinal venular oxygen saturation predict activity of proliferative diabetic retinopathy 3 months after panretinal photocoagulation

    DEFF Research Database (Denmark)

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

    2018-01-01

    .4 to -1.4), focal: -4.5% (95% CI -12.1 to 3.2)). In a multiple logistic regression model, increment in global retinal venular oxygen saturation (OR 1.30 per 1%-point increment, p=0.017) and decrement in AV oxygen saturation difference (OR 0.72 per 1%-point increment, p=0.016) at 3M independently predicted...

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

    International Nuclear Information System (INIS)

    Ogawa, S.; Lee, T.M.; Kay, A.R.; Tank, D.W.

    1990-01-01

    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

  5. A system for oxygen-15 labeled blood for medical applications

    International Nuclear Information System (INIS)

    Subramanyam, R.; Bucelewicz, W.M.; Hoop, B. Jr.; Jones, S.C.

    1977-01-01

    Oxygen-15 labeled compounds in blood have been used successfully for cerebral circulation and cerebral oxygen metabolism measurements. The present paper describes a system for the rapid sequential production of 15 O-HgB, C 15 O-Hgb and H 2 15 O in blood under sterile and pyrogen-free conditions. A tonometer has been adopted for labeling blood without hemolysis and foam production. (author)

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

    OpenAIRE

    Caprio, Di; Stokes, Chris; 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....

  7. Neuroprotection of hyperbaric oxygen therapy in sub-acute traumatic brain injury: not by immediately improving cerebral oxygen saturation and oxygen partial pressure.

    Science.gov (United States)

    Zhou, Bao-Chun; Liu, Li-Jun; Liu, Bing

    2016-09-01

    Although hyperbaric oxygen (HBO) therapy can promote the recovery of neural function in patients who have suffered traumatic brain injury (TBI), the underlying mechanism is unclear. We hypothesized that hyperbaric oxygen treatment plays a neuroprotective role in TBI by increasing regional transcranial oxygen saturation (rSO 2 ) and oxygen partial pressure (PaO 2 ). To test this idea, we compared two groups: a control group with 20 healthy people and a treatment group with 40 TBI patients. The 40 patients were given 100% oxygen of HBO for 90 minutes. Changes in rSO 2 were measured. The controls were also examined for rSO 2 and PaO 2 , but received no treatment. rSO 2 levels in the patients did not differ significantly after treatment, but levels before and after treatment were significantly lower than those in the control group. PaO 2 levels were significantly decreased after the 30-minute HBO treatment. Our findings suggest that there is a disorder of oxygen metabolism in patients with sub-acute TBI. HBO does not immediately affect cerebral oxygen metabolism, and the underlying mechanism still needs to be studied in depth.

  8. Study of Al-Si Alloy Oxygen Saturation on Its Microstructure and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Arkady Finkelstein

    2017-07-01

    Full Text Available One of the main goals of modern materials research is obtaining different microstructures and studying their influence on the mechanical properties of metals; aluminum alloys are particularly of interest due to their advanced performance. Traditionally, their required properties are obtained by alloying process, modification, or physical influence during solidification. The present work describes a saturation of the overheated AlSi7Fe1 casting alloy by oxides using oxygen blowing approach in overheated alloy. Changes in metals’ microstructural and mechanical properties are also described in the work. An Al10SiFe intermetallic complex compound was obtained as a preferable component to Al2O3 precipitation on it, and its morphology was investigated by scanning electron microscopy. The mechanical properties of the alloy after the oxygen blowing treatment are discussed in this work.

  9. Study of Al-Si Alloy Oxygen Saturation on Its Microstructure and Mechanical Properties.

    Science.gov (United States)

    Finkelstein, Arkady; Schaefer, Arseny; Chikova, Оlga; Borodianskiy, Konstantin

    2017-07-11

    One of the main goals of modern materials research is obtaining different microstructures and studying their influence on the mechanical properties of metals; aluminum alloys are particularly of interest due to their advanced performance. Traditionally, their required properties are obtained by alloying process, modification, or physical influence during solidification. The present work describes a saturation of the overheated AlSi₇Fe₁ casting alloy by oxides using oxygen blowing approach in overheated alloy. Changes in metals' microstructural and mechanical properties are also described in the work. An Al 10 SiFe intermetallic complex compound was obtained as a preferable component to Al₂O₃ precipitation on it, and its morphology was investigated by scanning electron microscopy. The mechanical properties of the alloy after the oxygen blowing treatment are discussed in this work.

  10. Effects of targeting lower versus higher arterial oxygen saturations on death or disability in preterm infants.

    Science.gov (United States)

    Askie, Lisa M; Darlow, Brian A; Davis, Peter G; Finer, Neil; Stenson, Ben; Vento, Maximo; Whyte, Robin

    2017-04-11

    The use of supplemental oxygen in the care of extremely preterm infants has been common practice since the 1940s. Despite this, there is little agreement regarding which oxygen saturation (SpO₂) ranges to target to maximise short- or long-term growth and development, while minimising harms. There are two opposing concerns. Lower oxygen levels (targeting SpO₂ at 90% or less) may impair neurodevelopment or result in death. Higher oxygen levels (targeting SpO₂ greater than 90%) may increase severe retinopathy of prematurity or chronic lung disease.The use of pulse oximetry to non-invasively assess neonatal SpO₂ levels has been widespread since the 1990s. Until recently there were no randomised controlled trials (RCTs) that had assessed whether it is better to target higher or lower oxygen saturation levels in extremely preterm infants, from birth or soon thereafter. As a result, there is significant international practice variation and uncertainty remains as to the most appropriate range to target oxygen saturation levels in preterm and low birth weight infants. 1. What are the effects of targeting lower versus higher oxygen saturation ranges on death or major neonatal and infant morbidities, or both, in extremely preterm infants?2. Do these effects differ in different types of infants, including those born at a very early gestational age, or in those who are outborn, without antenatal corticosteroid coverage, of male sex, small for gestational age or of multiple birth, or by mode of delivery? We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 4), MEDLINE via PubMed (1966 to 11 April 2016), Embase (1980 to 11 April 2016) and CINAHL (1982 to 11 April 2016). We also searched clinical trials databases, conference proceedings and the reference lists of retrieved articles for randomised controlled trials. Randomised controlled trials that enrolled babies born at less than 28

  11. Blood oxygen transport in common map turtles during simulated hibernation.

    Science.gov (United States)

    Maginniss, Leigh A; Ekelund, Summer A; Ultsch, Gordon R

    2004-01-01

    We assessed the effects of cold and submergence on blood oxygen transport in common map turtles (Graptemys geographica). Winter animals were acclimated for 6-7 wk to one of three conditions at 3 degrees C: air breathing (AB-3 degrees C), normoxic submergence (NS-3 degrees C), and hypoxic (PO2=49 Torr) submergence (HS-3 degrees C). NS-3 degrees C turtles exhibited a respiratory alkalosis (pH 8.07; PCO2=7.9 Torr; [lactate]=2.2 mM) relative to AB-3 degrees C animals (pH 7.89; PCO2=13.4 Torr; [lactate]=1.1 mM). HS-3 degrees C animals experienced a profound metabolic acidosis (pH 7.30; PCO2=7.9 Torr; [lactate]=81 mM). NS-3 degrees C turtles exhibited an increased blood O2 capacity; however, isoelectric focusing revealed no seasonal changes in the isohemoglobin (isoHb) profile. Blood O2 affinity was significantly increased by cold acclimation; half-saturation pressures (P50's) for air-breathing turtles at 3 degrees and 22 degrees C were 6.5 and 18.8 Torr, respectively. P50's for winter animals submerged in normoxic and hypoxic water were 5.2 and 6.5 Torr, respectively. CO2 Bohr slopes (Delta logP50/Delta pH) were -0.15, -0.16, and -0.07 for AB-3 degrees C, NS-3 degrees C, and HS-3 degrees C turtles, respectively; the corresponding value for AB-22 degrees C was -0.37. The O2 equilibrium curve (O2EC) shape was similar for AB-3 degrees C and NS-3 degrees C turtles; Hill plot n coefficients ranged from 1.8 to 2.0. The O2EC shape for HS-3 degrees C turtles was anomalous, exhibiting high O2 affinity below P50 and a right-shifted segment above half-saturation. We suggest that increases in Hb-O2 affinity and O2 capacity enhance extrapulmonary O2 uptake by turtles overwintering in normoxic water. The anomalous O2EC shape and reduced CO2 Bohr effect of HS-3 degrees C turtles may also promote some aerobic metabolism in hypoxic water.

  12. Near-infrared spectroscopy during stagnant ischemia estimates central venous oxygen saturation and mixed venous oxygen saturation discrepancy in patients with severe left heart failure and additional sepsis/septic shock

    OpenAIRE

    Mo?ina, Hugo; Podbregar, Matej

    2010-01-01

    Introduction Discrepancies of 5-24% between superior vena cava oxygen saturation (ScvO2) and mixed venous oxygen saturation (SvO2) have been reported in patients with severe heart failure. Thenar muscle tissue oxygenation (StO2) measured with near-infrared spectroscopy (NIRS) during arterial occlusion testing decreases slower in sepsis/septic shock patients (lower StO2 deoxygenation rate). The StO2 deoxygenation rate is influenced by dobutamine. The aim of this study was to determine the rela...

  13. Central venous oxygen saturation in septic shock - a marker of cardiac output, microvascular shunting and/or dysoxia?

    DEFF Research Database (Denmark)

    Haase, Nicolai; Perner, Anders

    2011-01-01

    Shock therapy aims at increasing central venous oxygen saturation (ScvO2), which is a marker of inadequate oxygen delivery. In this issue of Critical Care, Textoris and colleagues challenge this notion by reporting that high levels of ScvO2 are associated with mortality in patients with septic sh...

  14. Growth of the microalgae Neochloris oleoabundans at high partial oxygen pressures and sub-saturating light intensity

    NARCIS (Netherlands)

    Sousa, C.A.; Winter, de L.; Janssen, M.G.J.; Vermue, M.H.; Wijffels, R.H.

    2012-01-01

    The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at sub-saturating light intensity in a fully-controlled stirred tank photobioreactor. At the three partial oxygen pressures tested (PO2=0.24; 0.63; 0.84 bar), the specific growth rate was 1.38; 1.36 and 1.06

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

    International Nuclear Information System (INIS)

    Nissen, Johanna C.; Haneder, Stefan; Schoenberg, Stefan O.; Michaely, Henrik J.

    2010-01-01

    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 * -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.)

  16. Assessment of Arterial Oxygen Saturation by Pulse Oximetry Before, During and After Electroconvulsive Therapy

    Directory of Open Access Journals (Sweden)

    SH Tarig

    2006-07-01

    Full Text Available Introduction & Objective: Electroconvulsive therapy (ECT is used widely in psychiatric practice. The goal of anesthesia for ECT is the prevention of complications such as discomfort, fractures, aspiration of gastric contents and hypoxia. However, general anesthesia can cause some adverse effects as hypoxia. Prevention and treatment of hypoxia is important due to its undesirable effects on seizure duration and cardiovascular system. This study was designed to detect the incidence and probable times of desaturation in patients receiving ECT. Materials & Methods: This prospective randomized clinical trial was carried out on 100 patients (18-50 y/o with ASA I or II who were scheduled for ECT. After pre-oxygenation and similar anesthesia induction the patients received ECT. The patients were ventilated by oxygen and face masked until the return of their spontaneous respiration with adequate tidal volume and respiratory rate. Then they were transferred to recovery room where there was no oxygen supplementation. Oxygen saturation was measured by a Nell core pulse oximeter and was recorded at six stages: before and after anesthesia induction, during ECT, after ECT, 5 minutes after entering recovery room and before leaving there. The data were analyzed by standard statistical tests using SPSS software Results: Data analysis revealed that desaturation was not noticed at any stage except for the 5th stage (5 minutes after entering recovery room, when 13% of patients developed Sao2% less than 90%. Also there was a significant difference between Sao2% of patients between this stage (5th and other stages (p<0.001. Conclusion: According to our findings, appropriate oxygen supplementation and pulse oximetry monitoring during recovery period after ECT can be recommend

  17. Accuracy of pulse oximetry in detection of oxygen saturation in patients admitted to the intensive care unit of heart surgery: comparison of finger, toe, forehead and earlobe probes.

    Science.gov (United States)

    Seifi, Sohila; Khatony, Alireza; Moradi, Gholamreza; Abdi, Alireza; Najafi, Farid

    2018-01-01

    Heart surgery patients are more at risk of poor peripheral perfusion, and peripheral capillary oxygen saturation (SpO2) measurement is regular care for continuous analysis of blood oxygen saturation in these patients. With regard to controversial studies on accuracy of the current pulse oximetry probes and lack of data related to patients undergoing heart surgery, the present study was conducted to determine accuracy of pulse oximetry probes of finger, toe, forehead and earlobe in detection of oxygen saturation in patients admitted to intensive care units for coronary artery bypass surgery. In this clinical trial, 67 patients were recruited based on convenience sampling method among those admitted to intensive care units for coronary artery bypass surgery. The SpO2 value was measured using finger, toe, forehead and earlobe probes and then compared with the standard value of arterial oxygen saturation (SaO2). Data were entered into STATA-11 software and analyzed using descriptive, inferential and Bland-Altman statistical analyses. Highest and lowest correlational mean values of SpO2 and SaO2 were related to finger and earlobe probes, respectively. The highest and lowest agreement of SpO2 and SaO2 were related to forehead and earlobe probes. The SpO2 of earlobe probes due to lesser mean difference, more limited confidence level and higher agreement ration with SaO2 resulted by arterial blood gas (ABG) analysis had higher accuracy. Thus, it is suggested to use earlobe probes in patients admitted to the intensive care unit for coronary artery bypass surgery. Registration of this trial protocol has been approved in Iranian Registry of Clinical Trials at 2018-03-19 with reference IRCT20100913004736N22. "Retrospectively registered."

  18. Simultaneous estimation of arterial and venous oxygen saturation using a camera

    Science.gov (United States)

    van Gastel, Mark; Liang, Hangbing; Stuijk, Sander; de Haan, Gerard

    2018-02-01

    Optical monitoring of arterial blood oxygenation, SpO2, using cameras has recently been shown feasible by measuring the relative amplitudes of the remotely sensed PPG waveforms captured at different wavelengths. SvO2 measures the venous blood oxygenation which together with SpO2 provides an indication of tissue oxygen consumption. In contrast to SpO2 it usually still requires a blood sample from a pulmonary artery catheter. In this work we present a method which suggests simultaneous estimation of SpO2 and SvO2 with a camera. Contrary to earlier work, our method does not require external cuffs leading to better usability and improved comfort. Since the arterial blood varies synchronously with the heart rate, all frequencies outside the heart rate band are typically filtered out for SpO2 measurements. For SvO2 estimation, we include intensity variations in the respiratory frequency range since respiration modulates venous blood due to intrathoracic pressure variations in the chest and abdomen. Consequently, under static conditions, the two dominant components in the PPG signals are respiration and pulse. By measuring the amplitude ratios of these components, it seems possible to monitor both SpO2 and SvO2 continuously. We asked healthy subjects to follow an auditory breathing pattern while recording the face and hand. Results show a difference in estimated SpO2 and SvO2 values in the range 5-30 percent for both anatomical locations, which is normal for healthy people. This continuous, non-contact, method shows promise to alert the clinician to a change in patient condition sooner than SpO2 alone.

  19. Multi-modal in vivo imaging of brain blood oxygenation, blood flow and neural calcium dynamics during acute seizures

    Science.gov (United States)

    Ringuette, Dene; Jeffrey, Melanie A.; Carlen, Peter L.; Levi, Ofer

    2016-03-01

    Dysfunction of the vascular endothelium has been implicated in the development of epilepsy. To better understand the relation between vascular function and seizure and provide a foundation for interpreting results from functional imaging in chronic disease models, we investigate the relationship between intracellular calcium dynamics and local cerebral blood flow and blood oxygen saturation during acute seizure-like events and pharmacological seizure rescue. To probe the relation between the aforementioned physiological markers in an acute model of epilepsy in rats, we integrated three different optical modalities together with electrophysiological recordings: Laser speckle contrast imaging (LSCI) was used to study changes in flow speeds, Intrinsic optical signal imaging (IOSI) was used to monitor changes in oxygenated, de-oxygenated, and total hemoglobin concentration, and Calcium-sensitive dye imaging was used to monitor intracellular calcium dynamics. We designed a dedicated cortical flow chamber to remove superficial blood and dye resulting from the injection procedure, which reduced spurious artifacts. The near infrared light used for IOSI and LSCI was delivered via a light pipe integrated with the flow chamber to minimize the effect of fluid surface movement on illumination stability. Calcium-sensitive dye was injected via a glass electrode used for recording the local field potential. Our system allowed us to observe and correlate increases in intracellular calcium, blood flow and blood volume during seizure-like events and provide a quantitative analysis of neurovascular coupling changes associated with seizure rescue via injection of an anti-convulsive agent.

  20. [Association between oxygen saturation and cognitive function in older adults from longevity areas in China].

    Science.gov (United States)

    Su, L Q; Yin, Z X; Xu, N; Lyu, Y B; Luo, J S; Shi, X M

    2016-07-06

    To explore the relationship between oxygen saturation (SpO2) and cognitive function in older adults from longevity areas in China. A total of 2 285 participants aged ≥65 years according to the 2012 Chinese Longitudinal Healthy Longevity Survey were included in this study. Among them, 1 739 participants aged 65-99 years were randomly selected, and 546 participants aged ≥100 years were totally involved. A standardized questionaire was used to collect the information of demographic characteristics, life styles, disease history, etc. Cognitive function was evaluated using the Mini Mental State Examination Scale. Arterial oxygen saturation and heart rate were measured by pulse oximetry. Differences in cognitive function between the low SpO2 group (cognitive function. The total score of cognitive function was 22.6±9.7 for the 1 922 participants in the normal SpO2 group, and 18.8 ± 11.0 for the 363 participants in the low SpO2 group (t=6.11, Pcognitive impairment in the low SpO2 group was 36.6% (n=133), and 22.9% (n=441) in the normal SpO2 group (χ(2)=30.44, Pcognitive impairment increased with each year of increased age (OR 1.07; (95% CI: 1.05-1.09), Pcognitive impairment (OR 1.64; (95% CI: 1.11-2.43), OR 1.73; (95% CI: 1.27-2.35), OR 3.54; (95% CI: 2.62-4.79), OR 1.38; (95% CI: 1.02-1.86), OR 2.05; (95% CI: 1.34-3.13), OR 1.83; (95% CI: 1.13-2.97), respectively, Page group showed that the association between SpO2 and cognitive impairment was most significant in participants aged ≥90 years (OR 1.58; (95% CI: 1.09-2.28), P=0.016). Low oxygen saturation was associated with higher risk of cognitive impairment in our population of elderly adults.

  1. Blood oxygen and carbon dioxide transport in man

    OpenAIRE

    McElderry, Linda A.

    1981-01-01

    The effect of long term domiciliary oxygen therapy on the position and shape of the oxygen dissociation curve, together with other haematologic variables such as 2,3- diphosphoglycerate (2,3-DPG), haemoglobin concentration, packed cell volume, mean corpuscular haemoglobin concentration, and arterial blood gas and pH values, has been studied in patients with chronic bronchitis. Twenty-six patients were randomly allocated to receive either no oxygen therapy or 15 hours p...

  2. Oxygen dissociation curves of whole blood from the Egyptian free ...

    African Journals Online (AJOL)

    Tadarida aegyptiaca (mean body mass 13.5 g) is a fast flying insectivorous bat that hunts in open areas for extended periods, covering extensive distances during its foraging bouts. Whole blood samples taken from the wing arteries were analysed for 2,3-diphosphoglyceric acid, oxygen affinity and pH. The mean oxygen ...

  3. Cardiac function and oxygen saturation during maximal breath-holding in air and during whole-body surface immersion.

    Science.gov (United States)

    Marabotti, Claudio; Piaggi, Paolo; Menicucci, Danilo; Passera, Mirko; Benassi, Antonio; Bedini, Remo; L'Abbate, Antonio

    2013-09-01

    The magnitude of the oxygen-sparing effect induced by the diving response in humans is still under debate. We wished to compare cardiovascular changes during maximal breath-holding (BH) in air and during whole-body immersion at the surface in a group of BH divers. Twenty-one divers performed a maximal static apnea in air or during whole-body immersion. Dopplerechocardiography, arterial blood pressure and haemoglobin saturation (SaO₂) were obtained at the beginning of, and at 1/3, 2/3 and maximal BH time. BH time was on the average 3.6 ± 0.4 min, with no differences between the two conditions. SaO₂ significantly decreased during BH in both conditions, but was significantly higher during immersion as compared to the dry (P = 0.04). In both conditions, BH induced a significant linear increase in right ventricular diameter (P whole-body immersion, associated with reduced LV ejection fraction and progressive hindrance to diastolic filling. For a similar apnea duration, SaO₂ decreased less during immersed BH, indicating an O₂-sparing effect of diving, suggesting that interruption of apnea was not triggered by a threshold critical value of blood O₂ desaturation.

  4. Toe blood pressure and leg muscle oxygenation with body posture.

    Science.gov (United States)

    Rosales-Velderrain, Armando; Cardno, Michael; Mateus, Jaime; Kumar, Ravindra; Schlabs, Thomas; Hargens, Alan R

    2011-05-01

    In 1980 Katkov and Chestukhin measured blood pressures and oxygenation invasively at various body tilt angles at different locations on the body, including the foot. To our knowledge, such measurements have not been performed noninvasively. Therefore, the purpose of this study was to measure toe blood pressure (TBP) and lower limb muscle oxygenation noninvasively at various body tilt angles, and to assess the use of a Finometer for noninvasive TBP measurements. Our noninvasive results are compared with those performed by Katkov and Chestukhin. We hypothesized that: 1) the Finometer provides a noninvasive measurement of TBP at different tilt angles; and 2) muscle oxygenation is highest with 0 and -6 degrees, and decreases with increased head-up tilt (HUT). There were 10 subjects who were exposed to different body tilt angles (-6, 0, 10, 30, 70, and 90 degrees). At each angle we measured TBP noninvasively with a Finometer and muscle tissue oxygenation by near infrared spectroscopy. We found a strong correlation between TBP using the Finometer and TBP predicted by adding the hydrostatic component due to body tilt to the standard arm blood pressure measurement. At 10, 30, 70, and 90 degrees both TBP and tissue oxygenation were significantly different from the 0 degree (supine) level. Oxygenation decreased and TBP increased with higher HUT angles. No differences were observed in TBP or oxygenation between -6 and 0 degree. The Finometer accurately measures TBP noninvasively with body tilt. Also, muscle oxygenation is highest at small HUT angles and decreases with increased HUT.

  5. COMPARISON OF THE EFFECTIVENESS OF TWO LEVELS OF SUCTION PRESSURE ON OXYGEN SATURATION IN PATIENTS WITH ENDOTRACHEAL TUBE

    Directory of Open Access Journals (Sweden)

    Muhaji

    2017-12-01

    Full Text Available Background: Endotracheal suctioning is one of the common supportive measures in intensive care units (ICU, which may be related to complications such as hypoxia. However, a questionable efficacy is still identified to choose suctioning pressure between 130 mmHg and 140 mmHg that is effective for patients with endotracheal tube. Objective: To compare the effectiveness of 130 mmHg and 140 mmHg suctioning pressure on oxygen saturation in patients with endotracheal tube. Methods: This research used a quasy experimental design with pretest and posttest group. The study was conducted from 31 January to 1 March 2017 in the Hospital of Panti Wilasa Citarum and Hospital of Roemani Muhammadiyah Semarang. There were 30 samples recruited using consecutive sampling, with 15 assigned in the 130 mmHg and 140 mmHg suctioning pressure group. Pulse oximetry was used to measure oxygen saturation. Paired t-test and Independent t-test were used for data analysis. Results: Findings showed that there was a statistically significant effect of 130 and 140 mmHg suctioning pressure on oxygen saturation in patients with ETT with p-value <0.05. There was a significant mean difference of oxygen saturation between 130 mmHg and 140 mmHg suctioning pressure group with p-value 0.004 (<0.05. The mean difference of oxygen saturation between both groups was 13.157. Conclusion: The 140 mmHg suctioning pressure is more effective compared with 130 mmHg suctioning pressure in increasing oxygen saturation in patients with ETT.

  6. Near-simultaneous hemoglobin saturation and oxygen tension maps in mouse brain using an AOTF microscope.

    Science.gov (United States)

    Shonat, R D; Wachman, E S; Niu, W; Koretsky, A P; Farkas, D L

    1997-09-01

    A newly developed microscope using acousto-optic tunable filters (AOTFs) was used to generate in vivo hemoglobin saturation (SO2) and oxygen tension (PO2) maps in the cerebral cortex of mice. SO2 maps were generated from the spectral analysis of reflected absorbance images collected at different wavelengths, and PO2 maps were generated from the phosphorescence lifetimes of an injected palladium-porphyrin compound using a frequency-domain measurement. As the inspiratory O2 was stepped from hypoxia (10% O2), through normoxia (21% O2), to hyperoxia (60% O2), measured SO2 and PO2 levels rose accordingly and predictably throughout. A plot of SO2 versus PO2 in different arterial and venous regions of the pial vessels conformed to the sigmoidal shape of the oxygen-hemoglobin dissociation curve, providing further validation of the two mapping procedures. The study demonstrates the versatility of the AOTF microscope for in vivo physiologic investigation, allowing for the generation of nearly simultaneous SO2 and PO2 maps in the cerebral cortex, and the frequency-domain detection of phosphorescence lifetimes. This class of study opens up exciting new possibilities for investigating the dynamics of hemoglobin and O2 binding during functional activation of neuronal tissues.

  7. Investigation of spatial resolution dependent variability in transcutaneous oxygen saturation using point spectroscopy system

    Science.gov (United States)

    Philimon, Sheena P.; Huong, Audrey K. C.; Ngu, Xavier T. I.

    2017-08-01

    This paper aims to investigate the variation in one’s percent mean transcutaneous oxygen saturation (StO2) with differences in spatial resolution of data. This work required the knowledge of extinction coefficient of hemoglobin derivatives in the wavelength range of 520 - 600 nm to solve for the StO2 value via an iterative fitting procedure. A pilot study was conducted on three healthy subjects with spectroscopic data collected from their right index finger at different arbitrarily selected distances. The StO2 value estimated by Extended Modified Lambert Beer (EMLB) model revealed a higher mean StO2 of 91.1 ± 1.3% at a proximity distance of 30 mm compared to 60.83 ± 2.8% at 200 mm. The results showed a high correlation between data spatial resolution and StO2 value, and revealed a decrease in StO2 value as the sampling distance increased. The preliminary findings from this study contribute to the knowledge of the appropriate distance range for consistent and high repeatability measurement of skin oxygenation.

  8. A numerical two layer model for blood oxygenation in lungs

    International Nuclear Information System (INIS)

    Aminatai, A.

    2001-01-01

    In the modelling of the simultaneous transport of O 2 and CO 2 in the pulmonary circulation described in our earlier studies, the blood has been treated as a homogeneous layer of haemoglobin solution. Since the size of the erythrocyte is not negligible in comparison with that of the capillary, the blood can no longer be considered as a homogeneous fluid and hence, It is worthwhile to consider the blood flow as a two-phase flow consisting of cells and plasma. In the present study, the heterogeneous nature of blood has been proposed by considering the axial train model for the flow [whitmore (1967)], in order to analyze the effect of cell free plasma layer on the process of blood oxygenation in pulmonary capillaries. The proposed model consists of a core of suspended erythrocytes surrounded by a cell free plasma layer near the wall. The coupled system of convective diffusion equaions together with the physiologically relevant boundary, entrance and interface conditions is solved numerically by a four-point semi-implicit scheme to gether with a fixed point iterative technique. The distance traversed by the blood before getting fully oxygenated is computed. It is shown that the core haematocrit and the thickness of the cell depleted layer affect the oxygenation process significantly. It is found that (i) oxygen takes longest and carbondioxide is the fastest to attain equilibraton, (ii) the blood is completely oxygenated within one-fifth part of its transit and (iii) the rate of oxygenation is smaller in case of homogeneous model than that in heterogenous model in the capillary. Finally, the effect of various physiological parameters on the rate of oxygenation has been examined

  9. New hybrid reflectance optical pulse oximetry sensor for lower oxygen saturation measurement and for broader clinical application

    Science.gov (United States)

    Nogawa, Masamichi; Ching, Chong Thong; Ida, Takeyuki; Itakura, Keiko; Takatani, Setsuo

    1997-06-01

    A new reflectance pulse oximeter sensor for lower arterial oxygen saturation (Sa)2) measurement has been designed and evaluated in animals prior to clinical trials. The new sensor incorporates ten light emitting diode chips for each wavelength of 730 and 880 nm mounted symmetrically and at the radial separation distance of 7 mm around a photodiode chip. The separation distance of 7 mm was chosen to maximize the ratio of the pulsatile to the average plethysmographic signal level at each wavelength. The 730 and 880 wavelength combination was determined to obtain a linear relationship between the reflectance ratio of the 730 and 880 nm wavelengths and Sa)2. In addition to these features of the sensor, the Fast Fourier Transform method was employed to compute the pulsatile and average signal level at each wavelength. The performance of the new reflectance pulse oximeter sensor was evaluated in dogs in comparison to the 665/910 nm sensor. As predicted by the theoretical simulation based on a 3D photon diffusion theory, the 730/880 nm sensor demonstrated an excellent linearity over the SaO2 range from 100 to 30 percent. For the SaO2 range between 100 and 70 percent, the 665/910 and 730/880 sensors showed the standard error of around 3.5 percent and 2.1 percent, respectively, in comparison to the blood samples. For the range between 70 and 30 percent, the standard error of the 730/880 nm sensor was only 2.7 percent, while that of the 665/910 nm sensor was 9.5 percent. The 730/880 sensor showed improved accuracy for a wide range of SaO2 particularly over the range between 70 and 30 percent. This new reflectance sensor can provide noninvasive measurement of SaO2 accurately over the wide saturation range from 100 to 30 percent.

  10. 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.

  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

    2016-06-30

    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. Low pO2 Contributes to Potential Error in Oxygen Saturation Calculations Using a Point-of-Care Assay.

    Science.gov (United States)

    Gunsolus, Ian L; Love, Sara A; Kohl, Louis P; Schmidt, Martin; Apple, Fred S

    2017-12-20

    The present study addressed the accuracy of calculated oxygen saturation (sO2) using point-of-care (POC) testing compared with measured values on a blood gas analyzer. In total, 3,323 sO2 values were measured in 1,180 patients using a CO-oximeter (ABL 800 Flex; Radiometer, Copenhagen, Denmark). Measured parameters were then used to calculate an expected sO2 for the POC method (Abbott i-STAT; Abbott POC, Princeton, NJ). Cases in which calculated sO2 differed from measured sO2 by 10% or more were analyzed. Of the 3,323 comparisons performed, 260 (8%) showed discrepancies (± ≥10%) between measured and calculated sO2 values. Ninety-four of discrepant measurements (245 of 260) occurred when pO2 was less than 50 mm Hg. pH and bicarbonate distributions shifted to lower values in discrepant vs nondiscrepant cases. Our results suggest that the likelihood of discrepant sO2 is 27% among patients with pO2 less than 50 mm Hg. Direct measurement of sO2 by CO-oximetry is strongly suggested in this clinical scenario. © American Society for Clinical Pathology, 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  13. 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 in...

  14. Comparison of emissions and performance between saturated cyclic oxygenates and aromatics in a heavy-duty diesel engine

    NARCIS (Netherlands)

    Zhou, L.; Boot, M.D.; Johansson, B.H.

    2013-01-01

    Emissions and fuel economy are evaluated for two types of biofuels, namely 2-phenyl ethanol and cyclohexaneethanol. Both are derived from lignin, a form of lignocellulosic biomass. The former and latter oxygenates have an aromatic and aliphatic (i.e. saturated) ring structure, respectively. Two

  15. Short-term Effects of Air Pollution on Oxygen Saturation in a Cohort of Senior Adults in Steubenville, OH

    Science.gov (United States)

    Luttmann-Gibson, Heike; Sarnat, Stefanie Ebelt; Suh, Helen H.; Coull, Brent A.; Schwartz, Joel; Zanobetti, Antonella; Gold, Diane R.

    2014-01-01

    Objective We examine whether ambient air pollution is associated with oxygen saturation in 32 elderly subjects in Steubenville. Methods We used linear mixed models to examine the effects of fine particles (PM2.5), sulfate (SO42-), elemental carbon (EC), and gases on median oxygen saturation. Results An interquartile range (IQR) increase of 13.4 μg/m3 in PM2.5 on the previous day was associated with a decrease of -0.18% (95% CI: -0.31 to -0.06), and a 5.1 μg/m3 IQR increase in SO42- on the previous day was associated with a decrease of -0.16% (95% CI: -0.27 to -0.04) in oxygen saturation during the initial 5-min rest period of the protocol. Conclusions Increased exposure to air pollution, including the non-traffic pollutant SO42- from industrial sources, led to changes in oxygen saturation that may reflect particle-induced pulmonary inflammatory or vascular responses. PMID:24451609

  16. Short-term effects of air pollution on oxygen saturation in a cohort of senior adults in Steubenville, Ohio.

    Science.gov (United States)

    Luttmann-Gibson, Heike; Sarnat, Stefanie Ebelt; Suh, Helen H; Coull, Brent A; Schwartz, Joel; Zanobetti, Antonella; Gold, Diane R

    2014-02-01

    We examine whether ambient air pollution is associated with oxygen saturation in 32 elderly subjects in Steubenville, Ohio. We used linear mixed models to examine the effects of fine particulate matter less than 2.5 μm (PM(2.5)), sulfate (SO(4)(-2)), elemental carbon, and gases on median oxygen saturation. An interquartile range increase of 13.4 μg/m in PM(2.5) on the previous day was associated with a decrease of -0.18% (95% confidence interval: -0.31 to -0.06) and a 5.1 μg/m(3) interquartile range increase in SO(4)(-2) on the previous day was associated with a decrease of -0.16% (95% confidence interval: -0.27 to -0.04) in oxygen saturation during the initial 5-minute rest period of the protocol. Increased exposure to air pollution, including the nontraffic pollutant SO(4)(-2) from industrial sources, led to changes in oxygen saturation that may reflect particle-induced pulmonary inflammatory or vascular responses.

  17. T2-prepared velocity selective labelling : A novel idea for full-brain mapping of oxygen saturation

    NARCIS (Netherlands)

    Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra M A; van Bel, Frank; Benders, Manon J N L; Hendrikse, Jeroen; Petersen, Esben T

    2016-01-01

    BACKGROUND AND AIM: Disturbances in cerebral oxygenation saturation (SO2) have been linked to adverse outcome in adults, children, and neonates. In intensive care, the cerebral SO2 is increasingly being monitored by Near-InfraRed Spectroscopy (NIRS). Unfortunately NIRS has a limited penetration

  18. Monitoring of blood oxygenation in brain by resonance Raman spectroscopy

    DEFF Research Database (Denmark)

    Brazhe, Nadezda A; Thomsen, Kirsten; Lønstrup, Micael

    2018-01-01

    Blood oxygenation in cerebral vessels is an essential parameter to evaluate brain function and to investigate the coupling between local blood flow and neuronal activity. We apply resonance Raman spectroscopy in vivo to study hemoglobin oxygenation in cortex vessels of anesthetized ventilated mice....... We demonstrate that the pairs of Raman peaks at 1355 and1375 cm-1(symmetric vibrations of pyrrol half-rings in the heme molecule), 1552 and 1585 cm-1and 1602 and 1638 cm-1(vibrations of methine bridges in heme molecule) are reliable markers for quantitative estimation of the relative amount...

  19. Assessment of muscle tissue oxygen saturation after out-of-hospital cardiac arrest.

    Science.gov (United States)

    Orban, Jean-Christophe; Scarlatti, Audrey; Danin, Pierre-Eric; Dellamonica, Jean; Bernardin, Gilles; Ichai, Carole

    2015-12-01

    Pathophysiology of cardiac arrest corresponds to an ischemia-reperfusion syndrome with deep impairment of microcirculation. Muscular tissue oxygen saturation (StO2) is a noninvasive method of evaluation of microcirculation. Our study was aimed at assessing the prognosis value of muscular StO2 in patients admitted for out-of-hospital cardiac arrest (OHCA) and treated with hypothermia. We conducted a prospective bicentric observational study including OHCA patients treated with therapeutic hypothermia. Baseline StO2, derived variables (desaturation and resaturation slopes), and lactate levels were compared at different times between patients with good and poor outcomes. Prognosis was assessed by the Cerebral Performance Category (CPC) score at 6 months after admission (CPC 1-2, good outcome; CPC 3-5, poor outcome). Forty-four patients were included, 17 good and 27 poor outcomes at 6 months. At admission, StO2 and lactate levels were lower in good outcome patients. Desaturation and resaturation slopes did not differ between groups. After an OHCA treated with therapeutic hypothermia, StO2 was correlated with outcome. Further research is needed to better understand the pathophysiological process underlying our results. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Evaluation of pulse-oximetry oxygen saturation taken through skin protective covering

    Science.gov (United States)

    James, Jyotsna; Tiwari, Lokesh; Upadhyay, Pramod; Sreenivas, Vishnubhatla; Bhambhani, Vikas; Puliyel, Jacob M

    2006-01-01

    Background The hard edges of adult finger clip probes of the pulse oximetry oxygen saturation (POOS) monitor can cause skin damage if used for prolonged periods in a neonate. Covering the skin under the probe with Micropore surgical tape or a gauze piece might prevent such injury. The study was done to see if the protective covering would affect the accuracy of the readings. Methods POOS was studied in 50 full-term neonates in the first week of life. After obtaining consent from their parents the neonates had POOS readings taken directly (standard technique) and through the protective covering. Bland-Altman plots were used to compare the new method with the standard technique. A test of repeatability for each method was also performed. Results The Bland-Altman plots suggest that there is no significant loss of accuracy when readings are taken through the protective covering. The mean difference was 0.06 (SD of 1.39) and 0.04 (SD 1.3) with Micropore and gauze respectively compared to the standard method. The mean difference was 0.22 (SD 0.23) on testing repeatability with the standard method. Conclusion Interposing Micropore or gauze does not significantly affect the accuracy of the POOS reading. The difference between the standard method and the new method was less than the difference seen on testing repeatability of the standard method. PMID:16677394

  1. Development of theoretical oxygen saturation calibration curve based on optical density ratio and optical simulation approach

    Science.gov (United States)

    Jumadi, Nur Anida; Beng, Gan Kok; Ali, Mohd Alauddin Mohd; Zahedi, Edmond; Morsin, Marlia

    2017-09-01

    The implementation of surface-based Monte Carlo simulation technique for oxygen saturation (SaO2) calibration curve estimation is demonstrated in this paper. Generally, the calibration curve is estimated either from the empirical study using animals as the subject of experiment or is derived from mathematical equations. However, the determination of calibration curve using animal is time consuming and requires expertise to conduct the experiment. Alternatively, an optical simulation technique has been used widely in the biomedical optics field due to its capability to exhibit the real tissue behavior. The mathematical relationship between optical density (OD) and optical density ratios (ODR) associated with SaO2 during systole and diastole is used as the basis of obtaining the theoretical calibration curve. The optical properties correspond to systolic and diastolic behaviors were applied to the tissue model to mimic the optical properties of the tissues. Based on the absorbed ray flux at detectors, the OD and ODR were successfully calculated. The simulation results of optical density ratio occurred at every 20 % interval of SaO2 is presented with maximum error of 2.17 % when comparing it with previous numerical simulation technique (MC model). The findings reveal the potential of the proposed method to be used for extended calibration curve study using other wavelength pair.

  2. White Matter Damage Relates to Oxygen Saturation in Children With Sickle Cell Anemia Without Silent Cerebral Infarcts.

    Science.gov (United States)

    Kawadler, Jamie M; Kirkham, Fenella J; Clayden, Jonathan D; Hollocks, Matthew J; Seymour, Emma L; Edey, Rosanna; Telfer, Paul; Robins, Andrew; Wilkey, Olu; Barker, Simon; Cox, Tim C S; Clark, Chris A

    2015-07-01

    Sickle cell anemia is associated with compromised oxygen-carrying capability of hemoglobin and a high incidence of overt and silent stroke. However, in children with no evidence of cerebral infarction, there are changes in brain morphometry relative to healthy controls, which may be related to chronic anemia and oxygen desaturation. A whole-brain tract-based spatial statistics analysis was carried out in 25 children with sickle cell anemia with no evidence of abnormality on T2-weighted magnetic resonance imaging (13 male, age range: 8-18 years) and 14 age- and race-matched controls (7 male, age range: 10-19 years) to determine the extent of white matter injury. The hypotheses that white matter damage is related to daytime peripheral oxygen saturation and steady-state hemoglobin were tested. Fractional anisotropy was found to be significantly lower in patients in the subcortical white matter (corticospinal tract and cerebellum), whereas mean diffusivity and radial diffusivity were higher in patients in widespread areas. There was a significant negative relationship between radial diffusivity and oxygen saturation (Plevel negative relationship between radial diffusivity and hemoglobin (Pcell anemia, and provides for the first time direct evidence of a relationship between brain microstructure and markers of disease severity (eg, peripheral oxygen saturation and steady-state hemoglobin). This study suggests that diffusion tensor imaging metrics may serve as a biomarker for future trials of reducing hypoxic exposure. © 2015 American Heart Association, Inc.

  3. Therapeutic effect of forearm low level light treatment on blood flow, oxygenation, and oxygen consumption

    Science.gov (United States)

    Wang, Pengbo; Sun, Jiajing; Meng, Lingkang; Li, Zebin; Li, Ting

    2018-02-01

    Low level light/laser therapy (LLLT) is considered as a novel, non-invasive, and potential therapy in a variety of psychological and physical conditions, due to its effective intricate photobiomodulation. The mechanism of LLLT is that when cells are stimulated by photons, mitochondria produce a large quantity of ATP, which accelerates biochemical responses in the cell. It is of great significance to gain a clear insight into the change or interplay of various physiological parameters. In this study, we used functional near-infrared spectroscopy (fNIRS) and venous-occlusion plethysmography to measure the LLLT-induced changes in blood flow, oxygenation, and oxygen consumption in human forearms in vivo. Six healthy human participants (4 males and 2 females) were administered with 810-nm light emitted by LED array in ten minutes and blood flow, oxygenation and oxygen consumption were detected in the entire experiment. We found that LLLT induced an increase of blood flow and oxygen consumption on the treated site. Meanwhile, LLLT took a good role in promoting oxygenation of regional tissue, which was indicated by a significant increase of oxygenated hemoglobin concentration (Δ[HbO2]), a nearly invariable deoxygenated hemoglobin concentration (Δ[Hb]) and a increase of differential hemoglobin concentration (Δ[HbD] = Δ[HbO2] - Δ[Hb]). These results not only demonstrate enormous potential of LLLT, but help to figure out mechanisms of photobiomodulation.

  4. CELL RESPIRATION STUDIES : II. A COMPARATIVE STUDY OF THE OXYGEN CONSUMPTION OF BLOOD FROM NORMAL INDIVIDUALS AND PATIENTS WITH INCREASED LEUCOCYTE COUNTS (SEPSIS; CHRONIC MYELOGENOUS LEUCEMIA).

    Science.gov (United States)

    Daland, G A; Isaacs, R

    1927-06-30

    1. The oxygen consumption of blood of normal individuals, when the hemoglobin is saturated with oxygen, is practically zero within the limits of experimental error of the microspirometer used. 2. The oxygen consumed in a microspirometer by the blood of patients with chronic myelogenous leucemia with a high white blood cell count, and of one with leucocytosis from sepsis, was proportional to the number of adult polymorphonuclear neutrophils in the blood. 3. No correlation could be made between the rate of oxygen absorption and the total number of white blood cells in the blood, or the total number of immature cells, or the number of red blood cells, or the amount of oxyhemoglobin. 4. The blood of patients with chronic myelogenous leucemia continued to use oxygen in the microspirometer longer than that of normal individuals, and the hemoglobin, in the leucemic bloods, became desaturated even though exposed to air. 5. In blood in which the bulk. of the cells were immature and the mature cells few, the oxygen consumption was lower than in blood in which the mature cells predominated. The rate of oxygen consumption of the immature cells was relatively low as compared to the mature. 6. The slower rate of oxygen absorption by the immature leucocytes in chronic myelogenous leucemia as compared to the mature cells, places them, in accord with Warburg's reports, in the class of the malignant tissues in this respect rather than in the group of young or embryonic cells.

  5. Blood banking-induced alteration of red blood cell oxygen release ability.

    Science.gov (United States)

    Li, Yaojin; Xiong, Yanlian; Wang, Ruofeng; Tang, Fuzhou; Wang, Xiang

    2016-05-01

    Current blood banking procedures may not fully preserve red blood cell (RBC) function during storage, contributing to the decrease of RBC oxygen release ability. This study was undertaken to evaluate the impact of routine cold storage on RBC oxygen release ability. RBC units were collected from healthy donors and each unit was split into two parts (whole blood and suspended RBC) to exclude possible donor variability. Oxygen dissociation measurements were performed on blood units stored at 4 °C during a 5-week period. 2,3-diphosphoglycerate levels and fluorescent micrographs of erythrocyte band 3 were also analysed. P50 and oxygen release capacity decreased rapidly during the first 3 weeks, and then did not change significantly. In contrast, the kinetic properties (PO2-t curve and T*50) of oxygen release changed slowly during the first 3 weeks of storage, but then decreased significantly in the last 2 weeks. 2,3-diphosphoglycerate decreased quickly during the first 3 weeks of storage to almost undetectable levels. Band 3 aggregated significantly during the last 2 weeks of storage. RBC oxygen release ability appears to be sensitive to routine cold storage. The thermodynamic characteristics of RBC oxygen release ability changed mainly in the first 3 weeks of storage, due to the decrease of 2,3-diphosphoglycerate, whereas the kinetic characteristics of RBC oxygen release ability decreased significantly at the end of storage, probably affected by alterations of band 3.

  6. Improved sample capsule for determination of oxygen in hemolyzed blood

    Science.gov (United States)

    Malik, W. M.

    1967-01-01

    Sample capsule for determination of oxygen in hemolyzed blood consists of a measured section of polytetrafluoroethylene tubing equipped at each end with a connector and a stopcock valve. This method eliminates errors from air entrainment or from the use of mercury or syringe lubricant.

  7. 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)

    Duenzl, B.

    1981-01-01

    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 O 2 -saturation and the Hb-content were determined. By altering the maternal placental blood circulation the fetal arterial O 2 -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.) [de

  8. Calibration-free technique for the measurement of oxygen saturation changes in muscles of marine mammals and its proof of concept

    Science.gov (United States)

    Ortega-Martinez, Antonio; Goenka, Chhavi; Booker, Marloes; Grange, Robert M. H.; Hindle, Allyson G.; Franco, Walfre

    2018-02-01

    Marine mammals possess impressive breath-holding capabilities made possible by physiological adjustments during dives. Studying marine mammals in their natural environment unravels vital information about these physiological adjustments particularly when we can monitor altered dive behavior in response to stressful situations such as human-induced oceanic disturbances, presence of predators and altered prey distributions. An important indicator of physiological status during submergence is the change in oxygen saturation in the muscles and blood of these mammals. In this work, we aim to investigate oxygen storage and consumption in the muscles of free-diving elephant seals when exposed to disturbances such as sonar or predator sounds while they are at sea. Optical oxygen sensors are a mature technology with multiple medical applications that provide a way to measure oxygenation changes in biological tissues in a minimally invasive manner. While these sensors are well calibrated and readily available for humans, they are still inadequate for marine mammals primarily due to a very small number of test candidates and therefore little data is available for validation and calibration. We propose a probe geometry and associated mathematical model for measuring muscle oxygenation in seals based on near infrared diffuse transport with no need for calibration. A prototype based on this concept has been designed and tested on humans and rats. We use the test results to discuss the advantages and limitations of the approach. We also detail the constraints on size, sensor location, electronics, light source properties and detector characteristics posed by the unique biology of seals.

  9. Clinical score and arterial oxygen saturation in children with wheezing associated respiratory illness (WARI).

    Science.gov (United States)

    Sritippayawan, S; Deerojanawong, J; Prapphal, N

    2000-10-01

    To determine the correlation between clinical score (based on respiratory rate, chest wall retractions, air entry, wheezing, consciousness and audible wheezing) and arterial oxygen saturation (SaO2: measured by pulse oximetry) as well as the most appropriate total score for predicting hypoxemia (SaO2 WARI). 70 children (1 month-5 years old) hospitalized in the Department of Pediatrics, Chulalongkorn Hospital with the diagnosis of WARI from January 1, 1996 to December 31, 1996 were studied. Half of them were diagnosed to have acute lower respiratory tract infection (LRI) with wheezing while the remainder had reactive airway disease (RAD). Cross sectional, analytical study. In each group of patients, the clinical score and SaO2 were assessed by the same pediatrician throughout the study. The correlation between the clinical signs and SaO2 as well as the cut off point of total score for predicting hypoxemia were analyzed. The sensitivity, specificity and accuracy of that total score in predicting hypoxemia were also calculated. In both groups of patients (acute LRI with wheezing and RAD group), the clinical signs correlated with SaO2 were wheezing (rs = -0.67 and -0.47 respectively) and chest wall retractions (rs = -0.57 and -0.59 respectively). Total score was also correlated with SaO2 (rs = -0.68 and -0.5 respectively). The cut off point of total score in predicting hypoxemia was 4 providing 80 per cent sensitivity in both groups with accuracy 74.3 per cent and 80 per cent respectively. This clinical score may be used to assess the severity of hypoxemia in WARI patients. Wheezing, chest wall retractions and total score correlated well with SaO2. The total score > 4 was most appropriate in predicting hypoxemia in both children with RAD and wheezing associated with LRI.

  10. 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.

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

    International Nuclear Information System (INIS)

    Negargar, S.; Mahmoudpour, A.; Taheri, R.; Sarvin, S.

    2007-01-01

    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)

  12. Oxygen affinity and Bohr effect responses to 2,3-diphosphoglycerate in equine and human blood.

    Science.gov (United States)

    diBella, G; Scandariato, G; Suriano, O; Rizzo, A

    1996-05-01

    The dependence of blood oxygen affinity and the Bohr effect on the concentration of 2,3-diphosphoglycerate (DPG) in erythrocytes was investigated in 24 trotter horses and 24 healthy men. The oxygen tension at half saturation and standard conditions (P50st at pH 7.4, PCO2(40) mmHg and 37 degrees C) and the carbon dioxide or fixed-acid-induced Bohr effect (dlogP50/dpH) were determined. Samples of fresh blood and blood depleted of or enriched with DPG were studied. In the absence of measurable DPG, the equine and human blood had similar mean (SD) values of P50st (16.6 [0.6] and 16.2 [0.7] mmHg, respectively). In both species these values increased with increasing DPG, but the response of equine blood was significantly lower, at least up to physiological values (P50st = 24.6 [0.6] and 26.2 [0.7]) mmHg; DPG = 14([1.8] and 12.8 [1.2] mumol gHb-1, respectively, in fresh blood). For concentrations above 20 to 25 mumol gHb-1 of DPG the difference between the values of P50st in the two species tended to decrease because the response in human blood reached a plateau. The interactions between the Bohr effect and the concentration of DPG showed that in the horses, as in the men, the level of DPG played an important role in governing the relative magnitude of carbon dioxide and fixed acid factors. The difference between them, which is associated with the oxylabile carbamino binding, was greatest in DPG-depleted blood, but whereas in the men the difference was suppressed by an above normal DPG concentration, in the horses it was still measurable.

  13. Changes in retinal venular oxygen saturation predict activity of proliferative diabetic retinopathy 3 months after panretinal photocoagulation.

    Science.gov (United States)

    Torp, Thomas Lee; Kawasaki, Ryo; Wong, Tien Yin; Peto, Tunde; Grauslund, Jakob

    2018-03-01

    Proliferative diabetic retinopathy (PDR) is a severe blinding condition. We investigated whether retinal metabolism, measured by retinal oximetry, may predict PDR activity after panretinal laser photocoagulation (PRP). We performed a prospective, interventional, clinical study of patients with treatment-naive PDR. Wide-field fluorescein angiography (OPTOS, Optomap) and global and focal retinal oximetry (Oxymap T1) were performed at baseline (BL), and 3 months (3M) after PRP. Angiographic findings were used to divide patients according to progression or non-progression of PDR after PRP. We evaluated differences in global and focal retinal oxygen saturation between patients with and without progression of PDR after PRP treatment. We included 45 eyes of 37 patients (median age and duration of diabetes were 51.6 and 20 years). Eyes with progression of PDR developed a higher retinal venous oxygen saturation than eyes with non-progression at 3M (global: +5.9% (95% CI -1.5 to 12.9), focal: +5.4%, (95% CI -4.1 to 14.8)). Likewise, progression of PDR was associated with a lower arteriovenular (AV) oxygen difference between BL and 3M (global: -6.1%, (95% CI -13.4 to -1.4), focal: -4.5% (95% CI -12.1 to 3.2)). In a multiple logistic regression model, increment in global retinal venular oxygen saturation (OR 1.30 per 1%-point increment, p=0.017) and decrement in AV oxygen saturation difference (OR 0.72 per 1%-point increment, p=0.016) at 3M independently predicted progression of PDR. Development of higher retinal venular and lower AV global oxygen saturation independently predicts progression of PDR despite standard PRP and might be a potential non-invasive marker of angiogenic disease activity. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  14. Improved arterial blood oxygenation following intravenous infusion of cold supersaturated dissolved oxygen solution.

    Science.gov (United States)

    Grady, Daniel J; Gentile, Michael A; Riggs, John H; Cheifetz, Ira M

    2014-01-01

    One of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model. Juvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer's lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control. Five swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P < 0.05) and a significant decrease in PaCO2 (P < 0.05), with a corresponding normalization in arterial blood pH. Additionally, there was a significant decrease in core body temperature (P < 0.05) when compared to the baseline preinfusion state. A cold, supersaturated dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model.

  15. Angiotensin-converting enzyme genotype and arterial oxygen saturation at high altitude in Peruvian Quechua.

    Science.gov (United States)

    Bigham, Abigail W; Kiyamu, Melisa; León-Velarde, Fabiola; Parra, Esteban J; Rivera-Ch, Maria; Shriver, Mark D; Brutsaert, Tom D

    2008-01-01

    The I-allele of the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been associated with performance benefits at high altitude (HA). In n = 142 young males and females of largely Quechua origins in Peru, we evaluated 3 specific hypotheses with regard to the HA benefits of the I-allele: (1) the I-allele is associated with higher arterial oxygen saturation (Sa(O(2))) at HA, (2) the I-allele effect depends on the acclimatization state of the subjects, and (3) the putative I-allele effect on Sa(O(2)) is mediated by the isocapnic hypoxic ventilatory response (HVR, l/min(1)/% Sa(O(2))(1)). The subject participants comprised two different study groups including BLA subjects (born at low altitude) who were lifelong sea-level residents transiently exposed to hypobaric hypoxia (<24 h) and BHA subjects (born at HA) who were lifelong residents of HA. To control for the possibility of population stratification, Native American ancestry proportion (NAAP) was estimated as a covariate for each individual using a panel of 70 ancestry-informative molecular markers (AIMS). At HA, resting and exercise Sa(O(2)) was strongly associated with the ACE genotype, p = 0.008 with approximately 4% of the total variance in Sa(O(2)) attributed to ACE genotype. Moreover, I/I individuals maintained approximately 2.3 percentage point higher Sa(O(2)) compared to I/D and D/D. This I-allele effect was evident in both BLA and BHA groups, suggesting that acclimatization state has little influence on the phenotypic expression of the ACE gene. Finally, ACE genotype was not associated with the isocapnic HVR, although HVR had a strong independent effect on Sa(O(2)) (p = 0.001). This suggests that the I-allele effect on Sa(O(2)) is not mediated by the peripheral control of breathing, but rather by some other central cardiopulmonary effect of the ACE gene on the renin-angiotensin-aldosterone system (RAAS).

  16. Prognostic value of brachioradialis muscle oxygen saturation index and vascular occlusion test in septic shock patients.

    Science.gov (United States)

    Marín-Corral, J; Claverias, L; Bodí, M; Pascual, S; Dubin, A; Gea, J; Rodriguez, A

    2016-05-01

    To compare rSO2 (muscle oxygen saturation index) static and dynamic variables obtained by NIRS (Near Infrared Spectroscopy) in brachioradialis muscle of septic shock patients and its prognostic implications. Prospective and observational study. Intensive care unit. Septic shock patients and healthy volunteers. The probe of a NIRS device (INVOS 5100) was placed on the brachioradialis muscle during a vascular occlusion test (VOT). Baseline, minimum and maximum rSO2 values, deoxygenation rate (DeOx), reoxygenation slope (ReOx) and delta value. Septic shock patients (n=35) had lower baseline rSO2 (63.8±12.2 vs. 69.3±3.3%, p<0.05), slower DeOx (-0.54±0.31 vs. -0.91±0.35%/s, p=0.001), slower ReOx (2.67±2.17 vs. 9.46±3.5%/s, p<0.001) and lower delta (3.25±5.71 vs. 15.1±3.9%, p<0.001) when compared to healthy subjects (n=20). Among septic shock patients, non-survivors showed lower baseline rSO2 (57.0±9.6 vs. 69.8±11.3%, p=0.001), lower minimum rSO2 (36.0±12.8 vs. 51.3±14.8%, p<0.01) and lower maximum rSO2 values (60.6±10.6 vs. 73.3±11.2%, p<0.01). Baseline rSO2 was a good mortality predictor (AUC 0.79; 95%CI: 0.63-0.94, p<0.01). Dynamic parameters obtained with VOT did not improve the results. Septic shock patients present an important alteration of microcirculation that can be evaluated by NIRS with prognostic implications. Monitoring microvascular reactivity in the brachioradialis muscle using VOT with our device does not seem to improve the prognostic value of baseline rSO2. Copyright © 2015 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

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

    International Nuclear Information System (INIS)

    Budidha, K; Kyriacou, P A

    2014-01-01

    For the last two decades, pulse oximetry has been used as a standard procedure for monitoring arterial oxygen saturation (SpO 2 ). However, SpO 2 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 SpO 2 , 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 SpO 2 in the human auditory canal. A pilot study was carried out in 15 healthy volunteers to validate the feasibility of measuring PPGs and SpO 2  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 SpO 2  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 SpO 2 s even in the presence of

  18. In-vivo quantitative measurement of tissue oxygen saturation of human webbing using a transmission type continuous-wave near-infrared spectroscopy

    Science.gov (United States)

    Aizimu, Tuerxun; Adachi, Makoto; Nakano, Kazuya; Ohnishi, Takashi; Nakaguchi, Toshiya; Takahashi, Nozomi; Nakada, Taka-aki; Oda, Shigeto; Haneishi, Hideaki

    2018-02-01

    Near-infrared spectroscopy (NIRS) is a noninvasive method for monitoring tissue oxygen saturation (StO2). Many commercial NIRS devices are presently available. However, the precision of those devices is relatively poor because they are using the reflectance-model with which it is difficult to obtain the blood volume and other unchanged components of the tissue. Human webbing is a thin part of the hand and suitable to measure spectral transmittance. In this paper, we present a method for measuring StO2 of human webbing from a transmissive continuous-wave nearinfrared spectroscopy (CW-NIRS) data. The method is based on the modified Beer-Lambert law (MBL) and it consists of two steps. In the first step, we give a pressure to the upstream region of the measurement point to perturb the concentration of deoxy- and oxy-hemoglobin as remaining the other components and measure the spectral signals. From the measured data, spectral absorbance due to the components other than hemoglobin is calculated. In the second step, spectral measurement is performed at arbitrary time instance and the spectral absorbance obtained in the step 1 is subtracted from the measured absorbance. The tissue oxygen saturation (StO2) is estimated from the remained data. The method was evaluated on an arterial occlusion test (AOT) and a venous occlusion test (VOT). In the evaluation experiment, we confirmed that reasonable values of StO2 were obtained by the proposed method.

  19. Cerebral blood oxygenation measurements in neonates with optoacoustic technique

    Science.gov (United States)

    Herrmann, Stephen; Petrov, Irene Y.; Petrov, Yuriy; Richardson, C. Joan; Fonseca, Rafael A.; Prough, Donald S.; Esenaliev, Rinat O.

    2017-03-01

    Cerebral hypoxia is a major contributor to neonatal/infant mortality and morbidity including severe neurological complications such as mental retardation, cerebral palsy, motor impairment, and epilepsy. Currently, no technology is capable of accurate monitoring of neonatal cerebral oxygenation. We proposed to use optoacoustics for this application by probing the superior sagittal sinus (SSS), a large central cerebral vein. We developed and built a multi-wavelength, optical parametric oscillator (OPO) and laser diode optoacoustic systems for measurement of SSS blood oxygenation in the reflection mode through open anterior or posterior fontanelles and in the transmission mode through the skull in the occipital area. In this paper we present results of initial tests of the laser diode system for neonatal cerebral oxygenation measurements. First, the system was tested in phantoms simulating neonatal SSS. Then, using the data obtained in the phantoms, we optimized the system's hardware and software and tested it in neonates admitted in the Neonatal Intensive Care Unit. The laser diode system was capable of detecting SSS signals in the reflection mode through the open anterior and posterior fontanelles as well as in the transmission mode through the skull with high signal-to-noise ratio. Using the signals measured at different wavelengths and algorithms developed for oxygenation measurements, the laser diode system provided real-time, continuous oxygenation monitoring with high precision at all these locations.

  20. Relationship between retinal blood flow and arterial oxygen.

    Science.gov (United States)

    Cheng, Richard W; Yusof, Firdaus; Tsui, Edmund; Jong, Monica; Duffin, James; Flanagan, John G; Fisher, Joseph A; Hudson, Chris

    2016-02-01

    Vascular reactivity, the response of the vessels to a vasoactive stimulus such as hypoxia and hyperoxia, can be used to assess the vascular range of adjustment in which the vessels are able to compensate for changes in PO2. Previous studies in the retina have not accurately quantified retinal vascular responses and precisely targeted multiple PaO2 stimuli at the same time as controlling the level of carbon dioxide, thus precluding them from modelling the relationship between retinal blood flow and oxygen. The present study modelled the relationship between retinal blood flow and PaO2, showing them to be a combined linear and hyperbolic function. This model demonstrates that the resting tonus of the vessels is at the mid-point and that they have great vascular range of adjustment, compensating for decreases in oxygen above a PETCO2 of 32-37 mmHg but being limited below this threshold. Retinal blood flow (RBF) increases in response to a reduction in oxygen (hypoxia) but decreases in response to increased oxygen (hyperoxia). However, the relationship between blood flow and the arterial partial pressure of oxygen has not been quantified and modelled in the retina, particularly in the vascular reserve and resting tonus of the vessels. The present study aimed to determine the limitations of the retinal vasculature by modelling the relationship between RBF and oxygen. Retinal vascular responses were measured in 13 subjects for eight different blood gas conditions, with the end-tidal partial pressure of oxygen (PETCO2) ranging from 40-500 mmHg. Retinal vascular response measurements were repeated twice; using the Canon laser blood flowmeter (Canon Inc., Tokyo, Japan) during the first visit and using Doppler spectral domain optical coherence tomography during the second visit. We determined that the relationship between RBF and PaO2 can be modelled as a combination of hyperbolic and linear functions. We concluded that RBF compensated for decreases in arterial oxygen content

  1. Estimating skin blood saturation by selecting a subset of hyperspectral imaging data

    Science.gov (United States)

    Ewerlöf, Maria; Salerud, E. Göran; Strömberg, Tomas; Larsson, Marcus

    2015-03-01

    Skin blood haemoglobin saturation (?b) can be estimated with hyperspectral imaging using the wavelength (λ) range of 450-700 nm where haemoglobin absorption displays distinct spectral characteristics. Depending on the image size and photon transport algorithm, computations may be demanding. Therefore, this work aims to evaluate subsets with a reduced number of wavelengths for ?b estimation. White Monte Carlo simulations are performed using a two-layered tissue model with discrete values for epidermal thickness (?epi) and the reduced scattering coefficient (μ's ), mimicking an imaging setup. A detected intensity look-up table is calculated for a range of model parameter values relevant to human skin, adding absorption effects in the post-processing. Skin model parameters, including absorbers, are; μ's (λ), ?epi, haemoglobin saturation (?b), tissue fraction blood (?b) and tissue fraction melanin (?mel). The skin model paired with the look-up table allow spectra to be calculated swiftly. Three inverse models with varying number of free parameters are evaluated: A(?b, ?b), B(?b, ?b, ?mel) and C(all parameters free). Fourteen wavelength candidates are selected by analysing the maximal spectral sensitivity to ?b and minimizing the sensitivity to ?b. All possible combinations of these candidates with three, four and 14 wavelengths, as well as the full spectral range, are evaluated for estimating ?b for 1000 randomly generated evaluation spectra. The results show that the simplified models A and B estimated ?b accurately using four wavelengths (mean error 2.2% for model B). If the number of wavelengths increased, the model complexity needed to be increased to avoid poor estimations.

  2. Impaired Muscle Oxygenation and Elevated Exercise Blood Pressure in Hypertensive Patients: Links With Vascular Stiffness.

    Science.gov (United States)

    Dipla, Konstantina; Triantafyllou, Areti; Koletsos, Nikolaos; Papadopoulos, Stavros; Sachpekidis, Vasileios; Vrabas, Ioannis S; Gkaliagkousi, Eugenia; Zafeiridis, Andreas; Douma, Stella

    2017-08-01

    This study examined in vivo (1) skeletal muscle oxygenation and microvascular function, at rest and during handgrip exercise, and (2) their association with macrovascular function and exercise blood pressure (BP), in newly diagnosed, never-treated patients with hypertension and normotensive individuals. Ninety-one individuals (51 hypertensives and 40 normotensives) underwent office and 24-hour ambulatory BP, arterial stiffness, and central aortic BP assessment, followed by a 5-minute arterial occlusion and a 3-minute submaximal handgrip exercise. Changes in muscle oxygenated and deoxygenated hemoglobin and tissue oxygen saturation were continuously monitored by near-infrared spectroscopy and beat-by-beat BP by Finapres. Hypertensives had higher ( P age and body mass index (BMI) adjusted). When exercising at the same submaximal intensity, hypertensives required a significantly greater ( P hypertension exhibit prominent reductions in in vivo indices of skeletal muscle oxidative capacity, suggestive of mitochondrial dysfunction, and blunted muscle microvascular reactivity. These dysfunctions were associated with higher aortic systolic BP and arterial stiffness. Dysregulations in muscle oxygen delivery/utilization and microvascular stiffness, in hypertensive patients, partially contribute to their exaggerated BP during exercise. © 2017 American Heart Association, Inc.

  3. Determination of the PO2 temperature blood factor from oxygen dissociation curves.

    Science.gov (United States)

    Hérigault, R A; Soulard, C D; Teisseire, B P; Laurent, D N

    1983-01-01

    The variation with saturation of the temperature coefficient of PO2 in human blood (delta log PO2/delta T) was determined by continuous recording of the oxygen dissociation curve (ODC), at 37 degrees C and 25 degrees C, on the same blood samples. PCO2 and pH were held constant through an ODC run, and PCO2 was reduced at 25 degrees C to the value measured by anaerobic cooling of the same sample. delta log PO2/delta T was calculated from isosaturation points on the 37 and 25 degrees C curves. The temperature coefficient was also computed as an independent check on this method by determination of the effects of temperature (25, 30, 37 and 40 degrees C) on hemoglobin ligand interaction: fixed acid Bohr effect (delta log PO2/delta pH), carbamino-formation (delta log PO2/delta log PCO2) and hemoglobin oxygen affinity. The values of delta log PO2/delta T ratio obtained from the two different approaches were found to be in good agreement. The coefficient decreased when [H+] concentration was increased. A linear relationship between the Bohr factor and the temperature was found: delta log PO2/delta pH = 0.00267 T-0.520 (r = 0.85; n = 40) At 25 degrees C, the carbamino-formation was one order of magnitude lower than at 37 degrees C. Acid-base state and saturation value appeared to be major determinant factors for the temperature correction coefficient to be applied to blood PO2 values measured at standard (37 degrees C) temperature.

  4. Growth of the microalgae Neochloris oleoabundans at high partial oxygen pressures and sub-saturating light intensity.

    Science.gov (United States)

    Sousa, Cláudia; de Winter, Lenneke; Janssen, Marcel; Vermuë, Marian H; Wijffels, René H

    2012-01-01

    The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at sub-saturating light intensity in a fully-controlled stirred tank photobioreactor. At the three partial oxygen pressures tested (P(O)₂= 0.24; 0.63; 0.84 bar), the specific growth rate was 1.38; 1.36 and 1.06 day(-1), respectively. An increase of the P(CO)₂from 0.007 to 0.02 bar at P(O₂) of 0.84 bar resulted in an increase in the growth rate from 1.06 to 1.36 day(-1). These results confirm that the reduction of algal growth at high oxygen concentrations at sub-saturating light conditions is mainly caused by competitive inhibition of Rubisco. This negative effect on growth can be overcome by restoring the O(2)/CO(2) ratio by an increase in the partial carbon dioxide pressure. In comparison to general practice (P(O(2)) = 0.42 bar), working at partial O(2) pressure of 0.84 bar could reduce the energy requirement for degassing by a factor of 3-4. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Blood transfusion in preterm infants improves intestinal tissue oxygenation without alteration in blood flow.

    Science.gov (United States)

    Banerjee, J; Leung, T S; Aladangady, N

    2016-11-01

    The objective of the study was to investigate the splanchnic blood flow velocity and oximetry response to blood transfusion in preterm infants according to postnatal age. Preterm infants receiving blood transfusion were recruited to three groups: 1-7 (group 1; n = 20), 8-28 (group 2; n = 21) and ≥29 days of life (group 3; n = 18). Superior mesenteric artery (SMA) peak systolic (PSV) and diastolic velocities were measured 30-60 min pre- and post-transfusion using Doppler ultrasound scan. Splanchnic tissue haemoglobin index (sTHI), tissue oxygenation index (sTOI) and fractional tissue oxygen extraction (sFTOE) were measured from 15-20 min before to post-transfusion using near-infrared spectroscopy. The mean pretransfusion Hb in group 1, 2 and 3 was 11, 10 and 9 g/dl, respectively. The mean (SD) pretransfusion SMA PSV in group 1, 2 and 3 was 0·63 (0·32), 0·81 (0·33) and 0·97 (0·40) m/s, respectively, and this did not change significantly following transfusion. The mean (SD) pretransfusion sTOI in group 1, 2 and 3 was 36·7 (19·3), 44·6 (10·4) and 41·3 (10·4)%, respectively. The sTHI and sTOI increased (P transfusion in all groups. On multivariate analysis, changes in SMA PSV and sTOI following blood transfusion were not associated with PDA, feeding, pretransfusion Hb and mean blood pressure. Pretransfusion baseline splanchnic tissue oximetry and blood flow velocity varied with postnatal age. Blood transfusion improved intestinal tissue oxygenation without altering mesenteric blood flow velocity irrespective of postnatal ages. © 2016 International Society of Blood Transfusion.

  6. Renal blood flow and oxygenation drive nephron progenitor differentiation.

    Science.gov (United States)

    Rymer, Christopher; Paredes, Jose; Halt, Kimmo; Schaefer, Caitlin; Wiersch, John; Zhang, Guangfeng; Potoka, Douglas; Vainio, Seppo; Gittes, George K; Bates, Carlton M; Sims-Lucas, Sunder

    2014-08-01

    During kidney development, the vasculature develops via both angiogenesis (branching from major vessels) and vasculogenesis (de novo vessel formation). The formation and perfusion of renal blood vessels are vastly understudied. In the present study, we investigated the regulatory role of renal blood flow and O2 concentration on nephron progenitor differentiation during ontogeny. To elucidate the presence of blood flow, ultrasound-guided intracardiac microinjection was performed, and FITC-tagged tomato lectin was perfused through the embryo. Kidneys were costained for the vasculature, ureteric epithelium, nephron progenitors, and nephron structures. We also analyzed nephron differentiation in normoxia compared with hypoxia. At embryonic day 13.5 (E13.5), the major vascular branches were perfused; however, smaller-caliber peripheral vessels remained unperfused. By E15.5, peripheral vessels started to be perfused as well as glomeruli. While the interior kidney vessels were perfused, the peripheral vessels (nephrogenic zone) remained unperfused. Directly adjacent and internal to the nephrogenic zone, we found differentiated nephron structures surrounded and infiltrated by perfused vessels. Furthermore, we determined that at low O2 concentration, little nephron progenitor differentiation was observed; at higher O2 concentrations, more differentiation of the nephron progenitors was induced. The formation of the developing renal vessels occurs before the onset of blood flow. Furthermore, renal blood flow and oxygenation are critical for nephron progenitor differentiation. Copyright © 2014 the American Physiological Society.

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

    International Nuclear Information System (INIS)

    Yoshikawa, Hideto; Fueki, Noboru; Suzuki, Hisaharu; Sakuragawa, Norio; Iio, Masaaki

    1992-01-01

    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 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 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)

  8. Effects of Hemoglobin-Based Oxygen Carriers on Blood Coagulation

    Directory of Open Access Journals (Sweden)

    Kimia Roghani

    2014-12-01

    Full Text Available For many decades, Hemoglobin-based oxygen carriers (HBOCs have been central in the development of resuscitation agents that might provide oxygen delivery in addition to simple volume expansion. Since 80% of the world population lives in areas where fresh blood products are not available, the application of these new solutions may prove to be highly beneficial (Kim and Greenburg 2006. Many improvements have been made to earlier generation HBOCs, but various concerns still remain, including coagulopathy, nitric oxide scavenging, platelet interference and decreased calcium concentration secondary to volume expansion (Jahr et al. 2013. This review will summarize the current challenges faced in developing HBOCs that may be used clinically, in order to guide future research efforts in the field.

  9. The application of extended modified Lambert Beer model for measurement of blood carboxyhemoglobin and oxyhemoglobin saturation

    Directory of Open Access Journals (Sweden)

    Audrey Huong

    2014-05-01

    Full Text Available This work presents the use of extended Modified Lambert Beer (MLB model for accurate and continuous monitoring of percent blood carboxyhemoglobin (COHb (SCO and oxyhemoglobin (OxyHb saturation (SO2 via a fitting procedure. This quantification technique is based on the absorption characteristics of hemoglobin derivatives in the wavelength range of 520–600 nm to give the best estimates of the required parameters. A comparison of the performance of the developed model and MLB law is made using attenuation data from Monte Carlo simulations for a two-layered skin model. The results revealed a lower mean absolute error of 0.4% in the values estimated by the developed model as compared to 10% that is given by the MLB law. This study showed that the discussed approach is able to provide consistent and accurate measurement of blood SO2 and SCO across different skin pigmentations suggesting that it may potentially be used as an alternative means for clinical diagnosis of carbon monoxide (CO poisoning.

  10. Photoplethysmography for blood volumes and oxygenation changes during intermittent vascular occlusions.

    Science.gov (United States)

    Abay, T Y; Kyriacou, P A

    2018-06-01

    Photoplethysmography (PPG) is an optical technique that measures blood volume variations. The main application of dual-wavelength PPG is pulse oximetry, in which the arterial oxygen saturation (SpO[Formula: see text]) is calculated noninvasively. However, the PPG waveform contains other significant physiological information that can be used in conjunction to SpO[Formula: see text] for the assessment of oxygenation and blood volumes changes. This paper investigates the use of near infrared spectroscopy (NIRS) processing techniques for extracting relative concentration changes of oxygenated ([Formula: see text]HbO[Formula: see text]), reduced ([Formula: see text]HHb) and total haemoglobin ([Formula: see text]tHb) from dual-wavelength PPG signals during intermittent pressure-increasing vascular occlusions. A reflectance PPG sensor was attached on the left forearm of nineteen (n = 19) volunteers, along with a reference NIRS sensor positioned on the same forearm, above the left brachioradialis. The investigation protocol consisted of seven intermittent and pressure-increasing vascular occlusions. Relative changes in haemoglobin concentrations were obtained by applying the modified Beer-Lambert law to PPG signals, while oxygenation changes were estimated by the difference between red and infrared attenuations of DC PPGs (A[Formula: see text] = [Formula: see text]A[Formula: see text] - [Formula: see text]A[Formula: see text]) and by the conventional SpO[Formula: see text]. The [Formula: see text]HbO[Formula: see text], [Formula: see text]HHb, [Formula: see text]tHb from the PPG signals indicated significant changes in perfusion induced by either partial and complete occlusions (p < 0.05). The trends in the variables extracted from PPG showed good correlation with the same parameters measured by the reference NIRS monitor. Bland and Altman analysis of agreement between PPG and NIRS showed underestimation of the magnitude of changes by the PPG. A[Formula: see text

  11. A blood-oxygenation-dependent increase in blood viscosity due to a static magnetic field

    International Nuclear Information System (INIS)

    Yamamoto, Toru; Nagayama, Yuki; Tamura, Mamoru

    2004-01-01

    As the magnetic field of widely used MR scanners is one of the strongest magnetic fields to which people are exposed, the biological influence of the static magnetic field of MR scanners is of great concern. One magnetic interaction in biological subjects is the magnetic torque on the magnetic moment induced by biomagnetic substances. The red blood cell is a major biomagnetic substance, and the blood flow may be influenced by the magnetic field. However, the underlying mechanisms have been poorly understood. To examine the mechanisms of the magnetic influence on blood viscosity, we measured the time for blood to fall through a glass capillary inside and outside a 1.5 T MR scanner. Our in vitro results showed that the blood viscosity significantly increased in a 1.5 T MR scanner, and also clarified the mechanism of the interaction between red blood cells and the external magnetic field. Notably, the blood viscosity increased depending on blood oxygenation and the shear rate of the blood flow. Thus, our findings suggest that even a 1.5 T magnetic field may modulate blood flow

  12. Do dental procedures affect lung function and arterial oxygen saturation in asthmatic patients?

    Directory of Open Access Journals (Sweden)

    Magdy Mahmoud Emara

    2013-04-01

    Conclusion: Asthmatic patients may be at a higher risk of developing oxygen desaturation after dental procedures regardless of their type with and without local anesthesia and a decrease in PEF after dental procedures with local anesthesia.

  13. Dietary saturated and unsaturated fats as determinants of blood pressure and vascular function.

    Science.gov (United States)

    Hall, Wendy L

    2009-06-01

    The amount and type of dietary fat have long been associated with the risk of CVD. Arterial stiffness and endothelial dysfunction are important risk factors in the aetiology of CHD. A range of methods exists to assess vascular function that may be used in nutritional science, including clinic and ambulatory blood pressure monitoring, pulse wave analysis, pulse wave velocity, flow-mediated dilatation and venous occlusion plethysmography. The present review focuses on the quantity and type of dietary fat and effects on blood pressure, arterial compliance and endothelial function. Concerning fat quantity, the amount of dietary fat consumed habitually appears to have little influence on vascular function independent of fatty acid composition, although single high-fat meals postprandially impair endothelial function compared with low-fat meals. The mechanism is related to increased circulating lipoproteins and NEFA which may induce pro-inflammatory pathways and increase oxidative stress. Regarding the type of fat, cross-sectional data suggest that saturated fat adversely affects vascular function whereas polyunsaturated fat (mainly linoleic acid (18 : 2n-6) and n-3 PUFA) are beneficial. EPA (20 : 5n-3) and DHA (22 : 6n-3) can reduce blood pressure, improve arterial compliance in type 2 diabetics and dyslipidaemics, and augment endothelium-dependent vasodilation. The mechanisms for this vascular protection, and the nature of the separate physiological effects induced by EPA and DHA, are priorities for future research. Since good-quality observational or interventional data on dietary fatty acid composition and vascular function are scarce, no further recommendations can be suggested in addition to current guidelines at the present time.

  14. 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.

  15. Blood Transfusion Strategies in Patients Undergoing Extracorporeal Membrane Oxygenation

    Directory of Open Access Journals (Sweden)

    Hyoung Soo Kim

    2017-02-01

    Full Text Available Extracorporeal membrane oxygenation (ECMO is frequently associated with bleeding and coagulopathy complications, which may lead to the need for transfusion of multiple blood products. However, blood transfusions are known to increase morbidity and mortality, as well as hospital cost, in critically ill patients. In current practice, patients on ECMO receive a transfusion, on average, of 1-5 packed red blood cells (RBCs/day, with platelet transfusion accounting for the largest portion of transfusion volume. Generally, adult patients require more transfusions than neonates or children, and patients receiving venovenous ECMO for respiratory failure tend to need smaller transfusion volumes compared to those receiving venoarterial ECMO for cardiac failure. Observation studies have reported that a higher transfusion volume was associated with increased mortality. To date, the evidence for transfusion in patients undergoing ECMO is limited; most knowledge on transfusion strategies was extrapolated from studies in critically ill patients. However, current data support a restrictive blood transfusion strategy for ECMO patients, and a low transfusion trigger seems to be safe and reasonable.

  16. Detection of haemoglobins with abnormal oxygen affinity by single blood gas analysis and 2,3-diphosphoglycerate measurement.

    Science.gov (United States)

    Guerrini, G; Morabito, A; Samaja, M

    2000-10-01

    The aim is to determine if a single measurement of blood 2,3-diphosphoglycerate combined with gas analysis (pH, PCO2, PO2 and saturation) can identify the cause of an altered blood-oxygen affinity: the presence of an abnormal haemoglobin or a red cell disorder. The population (n=94) was divided into healthy controls (A, n=14), carriers of red cell disorders (B, n=72) and carriers of high oxygen affinity haemoglobins (C, n=8). Those variables were measured both in samples equilibrated at selected PCO2 and PO2 and in venous blood. In the univariable approach applied to equilibrated samples, we correctly identified C subjects in 93.6% or 96.8% of the cases depending on the selected variable, the standard P50 (PO2 at which 50% of haemoglobin is oxygenated) or a composite variable calculated from the above measurements. After introducing the haemoglobin concentration as a further discriminating variable, the A and B subjects were correctly identified in 91.9% or 94.2% of the cases, respectively. These figures become 93.0% or 86.1%, and 93.7% or 94.9% of the cases when using direct readings from venous blood, thereby avoiding the blood equilibration step. This test is feasible also in blood samples stored at 4 degrees C for 48 h, or at room temperature for 8 h.

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

    International Nuclear Information System (INIS)

    Grandia, Fidel; Domenech, Cristina; Arcos, David; Duro, Lara

    2006-11-01

    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 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

  18. 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

  19. 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.

  20. Cerebral blood flow and cerebral oxygen metabolism in thalamic hemorrhage

    International Nuclear Information System (INIS)

    Yasui, Nobuyuki; Asakura, Ken

    1987-01-01

    Cerebral blood flow (CBF), cerebral oxygen consumption (CMRO 2 ), oxygen extraction fraction (OEF) and cerebral blood volume (CBV) were studied in 20 cases of thalamic hemorrhage using positron CT and 15 O labeled gas steady-state inhalation method. CBF reduction was limited around the thalamus in the small sized hematoma. CBF were significantly diminished in the mean cortical, parietal, temporal, basal ganglia and thalamic area ipsilateral and cerebellar cortex contralateral to the medium sized hematoma. There was bilateral and diffuse CBF reduction in the large sized hematoma which was caused by increased intracranial pressure. CMRO 2 value were similary changed as CBF. OEF change showed within normal limit. Diffuse CBV reduction was observed in the large sized hematoma. This reduction was the result of decreased vascular bed caused by mass effect of the hematoma and hydrocephalus. Effect of surgical treatment such as ventricular drainage and hematoma evacuation were also discussed in correlation to CBF in some case using positron and single photon ECT. (author)

  1. 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

  2. Hypercapnic Acidosis Preserves Gastric Mucosal Microvascular Oxygen Saturation in a Canine Model of Hemorrhage.

    NARCIS (Netherlands)

    Schwartges, Ingo; Picker, Olaf; Beck, Christopher; Scheeren, Thomas W. L.; Schwarte, Lothar A.

    2010-01-01

    The authors aimed to clarify the effects of hypercapnic acidosis and its timing on gastric mucosal oxygenation in a canine model of hemorrhage. This was designed as a prospective, controlled, randomized animal study set in a university research laboratory. Five chronically instrumented dogs were

  3. Assessment of tissue oxygen saturation during a vascular occlusion test using near-infrared spectroscopy: the role of probe spacing and measurement site studied in healthy volunteers

    NARCIS (Netherlands)

    Bezemer, R.; Lima, A.; Myers, D.; Klijn, E.; Heger, M.; Goedhart, P.T.; Bakker, J.; Ince, C.

    2009-01-01

    INTRODUCTION: To assess potential metabolic and microcirculatory alterations in critically ill patients, near-infrared spectroscopy (NIRS) has been used, in combination with a vascular occlusion test (VOT), for the non-invasive measurement of tissue oxygen saturation (StO2), oxygen consumption, and

  4. The effect of glycerol on regional cerebral blood flow, blood volume and oxygen metabolism

    International Nuclear Information System (INIS)

    Ishikawa, Masatsune; Kikuchi, Haruhiko; Nagata, Izumi; Yamagata, Sen; Taki, Waro; Kobayashi, Akira; Yonekura, Yoshiharu; Nishizawa, Sadahiko.

    1989-01-01

    Using positron emission tomography with 15 O-labelled CO 2 , O 2 and CO gases, the effects of glycerol on regional cerebral blood flow (CBF), blood volume (CBV) and oxygen metabolism (CMRO 2 ) were investigated in 6 patients with meningioma accompanying peritumoral brain edema. The same study was done in 5 normal volunteers. The changes of blood gases, hematocrit and hemoglobin were also examined. After a drip infusion of glycerol, the regional CBF increased not only in the peritumoral cortex and white matter but also in the intact cortex and white matter on the contralateral side. The increase of CBF was extensive and substantially there were no regional differences. In contrast, the changes of CMRO 2 were not significant. This was derived from the increase in oxygen extraction fraction throughout extensive areas including the peritumoral area. There were no changes in CBV. Hematocrit and hemoglobin decreased to a small degree. In the normal volunteers, the same findings were noted. Thus, glycerol increases the functional reserve for cerebral oxygen metabolism, not only in the peritumoral regions but also in the intact regions. The effects of glycerol on hemodynamics and metabolism were discussed with reference to some differences from mannitol. (author)

  5. Simultaneous, noninvasive, in vivo, continuous monitoring of hematocrit, vascular volume, hemoglobin oxygen saturation, pulse rate and breathing rate in humans and other animal models using a single light source

    Science.gov (United States)

    Dent, Paul; Tun, Sai Han; Fillioe, Seth; Deng, Bin; Satalin, Josh; Nieman, Gary; Wilcox, Kailyn; Searles, Quinn; Narsipur, Sri; Peterson, Charles M.; Goodisman, Jerry; Mostrom, James; Steinmann, Richard; Chaiken, J.

    2018-02-01

    We previously reported a new algorithm "PV[O]H" for continuous, noninvasive, in vivo monitoring of hematocrit changes in blood and have since shown its utility for monitoring in humans during 1) hemodialysis, 2) orthostatic perturbations and 3) during blood loss and fluid replacement in a rat model. We now show that the algorithm is sensitive to changes in hemoglobin oxygen saturation. We document the phenomenology of the effect and explain the effect using new results obtained from humans and rat models. The oxygen sensitivity derives from the differential absorption of autofluorescence originating in the static tissues by oxy and deoxy hemoglobin. Using this approach we show how to perform simultaneous, noninvasive, in vivo, continuous monitoring of hematocrit, vascular volume, hemoglobin oxygen saturation, pulse rate and breathing rate in mammals using a single light source. We suspect that monitoring of changes in this suite of vital signs can be provided with improved time response, sensitivity and precision compared to existing methodologies. Initial results also offer a more detailed glimpse into the systemic oxygen transport in the circulatory system of humans.

  6. Red blood cell transfusions and tissue oxygenation in anemic hematology outpatients.

    Science.gov (United States)

    Yuruk, Koray; Bartels, Sebastiaan A; Milstein, Dan M J; Bezemer, Rick; Biemond, Bart J; Ince, Can

    2012-03-01

    There is little clinical evidence that red blood cell (RBC) transfusions improve oxygen availability at the microcirculatory level. We tested the hypotheses that anemia in chronically anemic patients with relatively healthy microcirculation would be associated with low tissue hemoglobin (Hb) and tissue oxygenation levels and that these conditions would be improved after RBC transfusions. Near-infrared spectroscopy (NIRS) was used to determine tissue oxygen saturation (StO(2)) and tissue Hb index (THI; an index of the amount of Hb in the NIRS measurement volume) in the thenar eminence and sublingual tissue before and 30 minutes after RBC transfusions in 20 chronically anemic hematology outpatients. Data are presented as median (25%-75%). The patients received three (two to three) bags of RBCs in saline-adenine-glucose-mannitol with an age of 21 (7-21) days, which was infused intravenously at the rate of 0.7 bag/hr. RBC transfusions significantly increased hematocrit level from 26% (24%-28%) to 32% (30%-34%; p viscosity from 3.4 (3.1-3.5) mPa/sec to 4.2 (4.0-4.5) mPa/sec (p < 0.0001), thenar StO(2) from 81% (80%-84%) to 86% (81%-89%; p = 0.002), thenar THI from 11.2 (9.3-13.3) AU to 13.7 (9.7-15.3) AU (p = 0.024), sublingual StO(2) from 86% (81%-89%) to 91% (86%-92%; p < 0.0001), and sublingual THI from 15.2 (13.0-17.4) AU to 17.2 (13.5-19.7) AU (p = 0.040). Although anemia in chronically anemic hematology outpatients was not associated with low StO(2) and THI levels, RBC transfusions were successful in improving these variables. © 2011 American Association of Blood Banks.

  7. Methods of Blood Oxygen Level-Dependent Magnetic Resonance Imaging Analysis for Evaluating Renal Oxygenation

    Directory of Open Access Journals (Sweden)

    Fen Chen

    2018-03-01

    Full Text Available Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI has recently been utilized as a noninvasive tool for evaluating renal oxygenation. Several methods have been proposed for analyzing BOLD images. Regional ROI selection is the earliest and most widely used method for BOLD analysis. In the last 20 years, many investigators have used this method to evaluate cortical and medullary oxygenation in patients with ischemic nephropathy, hypertensive nephropathy, diabetic nephropathy, chronic kidney disease (CKD, acute kidney injury and renal allograft rejection. However, clinical trials of BOLD MRI using regional ROI selection revealed that it was difficult to distinguish the renal cortico-medullary zones with this method, and that it was susceptible to observer variability. To overcome these deficiencies, several new methods were proposed for analyzing BOLD images, including the compartmental approach, fractional hypoxia method, concentric objects (CO method and twelve-layer concentric objects (TLCO method. The compartmental approach provides an algorithm to judge whether the pixel belongs to the cortex or medulla. Fractional kidney hypoxia, measured by using BOLD MRI, was negatively correlated with renal blood flow, tissue perfusion and glomerular filtration rate (GFR in patients with atherosclerotic renal artery stenosis. The CO method divides the renal parenchyma into six or twelve layers of thickness in each coronal slice of BOLD images and provides a R2* radial profile curve. The slope of the R2* curve associated positively with eGFR in CKD patients. Indeed, each method invariably has advantages and disadvantages, and there is generally no consensus method so far. Undoubtedly, analytic approaches for BOLD MRI with better reproducibility would assist clinicians in monitoring the degree of kidney hypoxia and thus facilitating timely reversal of tissue hypoxia.

  8. Metabolism of Citrate and Other Carboxylic Acids in Erythrocytes As a Function of Oxygen Saturation and Refrigerated Storage

    Directory of Open Access Journals (Sweden)

    Travis Nemkov

    2017-10-01

    Full Text Available State-of-the-art proteomics technologies have recently helped to elucidate the unanticipated complexity of red blood cell metabolism. One recent example is citrate metabolism, which is catalyzed by cytosolic isoforms of Krebs cycle enzymes that are present and active in mature erythrocytes and was determined using quantitative metabolic flux analysis. In previous studies, we reported significant increases in glycolytic fluxes in red blood cells exposed to hypoxia in vitro or in vivo, an observation relevant to transfusion medicine owing to the potential benefits associated with hypoxic storage of packed red blood cells. Here, using a combination of steady state and quantitative tracing metabolomics experiments with 13C1,2,3-glucose, 13C6-citrate, 13C515N2-glutamine, and 13C1-aspartate via ultra-high performance liquid chromatography coupled on line with mass spectrometry, we observed that hypoxia in vivo and in vitro promotes consumption of citrate and other carboxylates. These metabolic reactions are theoretically explained by the activity of cytosolic malate dehydrogenase 1 and isocitrate dehydrogenase 1 (abundantly represented in the red blood cell proteome, though moonlighting functions of additional enzymes cannot be ruled out. These observations enhance understanding of red blood cell metabolic responses to hypoxia, which could be relevant to understand systemic physiological and pathological responses to high altitude, ischemia, hemorrhage, sepsis, pulmonary hypertension, or hemoglobinopathies. Results from this study will also inform the design and testing of novel additive solutions that optimize red blood cell storage under oxygen-controlled conditions.

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

    International Nuclear Information System (INIS)

    Tsisar, V.P.; Fedirko, V.N.; Eliseeva, O.I.

    2007-01-01

    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 Fe 3 O 4 . Inner part of double oxide based on the matrix is composed of Fe 3 O 4 for Armco-Fe, Fe 1+x Cr 2-x O 4 for martensitic 0.2 C-13 Cr and ferritic-martensitic EP823 steels and Fe 1+x Cr 2- xO 4 +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

  10. Alveolar gas exchange and tissue oxygenation during incremental treadmill exercise, and their associations with blood O2 carrying capacity

    Directory of Open Access Journals (Sweden)

    Antti-Pekka E. Rissanen

    2012-07-01

    Full Text Available The magnitude and timing of oxygenation responses in highly active leg muscle, less active arm muscle, and cerebral tissue, have not been studied with simultaneous alveolar gas exchange measurement during incremental treadmill exercise. Nor is it known, if blood O2 carrying capacity affects the tissue-specific oxygenation responses. Thus, we investigated alveolar gas exchange and tissue (m. vastus lateralis, m. biceps brachii, cerebral cortex oxygenation during incremental treadmill exercise until volitional fatigue, and their associations with blood O2 carrying capacity in 22 healthy men. Alveolar gas exchange was measured, and near-infrared spectroscopy (NIRS was used to monitor relative concentration changes in oxy- (Δ[O2Hb], deoxy- (Δ[HHb] and total hemoglobin (Δ[tHb], and tissue saturation index (TSI. NIRS inflection points (NIP, reflecting changes in tissue-specific oxygenation, were determined and their coincidence with ventilatory thresholds (anaerobic threshold (AT, respiratory compensation point (RC; V-slope method was examined. Blood O2 carrying capacity (total hemoglobin mass (tHb-mass was determined with the CO-rebreathing method. In all tissues, NIPs coincided with AT, whereas RC was followed by NIPs. High tHb-mass associated with leg muscle deoxygenation at peak exercise (e.g., Δ[HHb] from baseline walking to peak exercise vs. tHb-mass: r = 0.64, p < 0.01, but not with arm muscle- or cerebral deoxygenation. In conclusion, regional tissue oxygenation was characterized by inflection points, and tissue oxygenation in relation to alveolar gas exchange during incremental treadmill exercise resembled previous findings made during incremental cycling. It was also found out, that O2 delivery to less active m. biceps brachii may be limited by an accelerated increase in ventilation at high running intensities. In addition, high capacity for blood O2 carrying was associated with a high level of m. vastus lateralis deoxygenation at peak

  11. Zolpidem reduces the blood oxygen level-dependent signal during visual system stimulation.

    Science.gov (United States)

    Licata, Stephanie C; Lowen, Steven B; Trksak, George H; Maclean, Robert R; Lukas, Scott E

    2011-08-15

    Zolpidem is a short-acting imidazopyridine hypnotic that binds at the benzodiazepine binding site on specific GABA(A) receptors to enhance fast inhibitory neurotransmission. The behavioral and receptor pharmacology of zolpidem has been studied extensively, but little is known about its neuronal substrates in vivo. In the present within-subject, double-blind, and placebo-controlled study, blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) at 3 Tesla was used to assess the effects of zolpidem within the brain. Healthy participants (n=12) were scanned 60 min after acute oral administration of zolpidem (0, 5, 10, or 20mg), and changes in BOLD signal were measured in the visual cortex during presentation of a flashing checkerboard. Heart rate and oxygen saturation were monitored continuously throughout the session. Zolpidem (10 and 20mg) reduced the robust visual system activation produced by presentation of this stimulus, but had no effects on physiological activity during the fMRI scan. Zolpidem's modulation of the BOLD signal within the visual cortex is consistent with the abundant distribution of GABA(A) receptors localized in this region, as well as previous studies showing a relationship between increased GABA-mediated neuronal inhibition and a reduction in BOLD activation. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Zolpidem reduces the blood oxygen level-dependent signal during visual system stimulation

    Science.gov (United States)

    Licata, Stephanie C.; Lowen, Steven B.; Trksak, George H.; MacLean, Robert R.; Lukas, Scott E.

    2011-01-01

    Zolpidem is a short-acting imidazopyridine hypnotic that binds at the benzodiazepine binding site on specific GABAA receptors to enhance fast inhibitory neurotransmission. The behavioral and receptor pharmacology of zolpidem has been studied extensively, but little is known about its neuronal substrates in vivo. In the present within-subject, double-blind, and placebo-controlled study, blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) at 3 Tesla was used to assess the effects of zolpidem within the brain. Healthy participants (n=12) were scanned 60 minutes after acute oral administration of zolpidem (0, 5, 10, or 20 mg), and changes in BOLD signal were measured in the visual cortex during presentation of a flashing checkerboard. Heart rate and oxygen saturation were monitored continuously throughout the session. Zolpidem (10 and 20 mg) reduced the robust visual system activation produced by presentation of this stimulus, but had no effects on physiological activity during the fMRI scan. Zolpidem’s modulation of the BOLD signal within the visual cortex is consistent with the abundant distribution of GABAA receptors localized in this region, as well as previous studies showing a relationship between increased GABA-mediated neuronal inhibition and a reduction in BOLD activation. PMID:21640782

  13. Acute effect of glucose on cerebral blood flow, blood oxygenation, and oxidative metabolism.

    Science.gov (United States)

    Xu, Feng; Liu, Peiying; Pascual, Juan M; Xiao, Guanghua; Huang, Hao; Lu, Hanzhang

    2015-02-01

    While it is known that specific nuclei of the brain, for example hypothalamus, contain glucose-sensing neurons thus their activity is affected by blood glucose level, the effect of glucose modulation on whole-brain metabolism is not completely understood. Several recent reports have elucidated the long-term impact of caloric restriction on the brain, showing that animals under caloric restriction had enhanced rate of tricarboxylic acid cycle (TCA) cycle flux accompanied by extended life span. However, acute effect of postprandial blood glucose increase has not been addressed in detail, partly due to a scarcity and complexity of measurement techniques. In this study, using a recently developed noninvasive MR technique, we measured dynamic changes in global cerebral metabolic rate of O2 (CMRO2 ) following a 50 g glucose ingestion (N = 10). A time dependent decrease in CMRO2 was observed, which was accompanied by a reduction in oxygen extraction fraction (OEF) with unaltered cerebral blood flow (CBF). At 40 min post-ingestion, the amount of CMRO2 reduction was 7.8 ± 1.6%. A control study without glucose ingestion was performed (N = 10), which revealed no changes in CMRO2 , CBF, or OEF, suggesting that the observations in the glucose study was not due to subject drowsiness or fatigue after staying inside the scanner. These findings suggest that ingestion of glucose may alter the rate of cerebral metabolism of oxygen in an acute setting. © 2014 Wiley Periodicals, Inc.

  14. Cutaneous Mitochondrial PO2, but Not Tissue Oxygen Saturation, Is an Early Indicator of the Physiologic Limit of Hemodilution in the Pig.

    Science.gov (United States)

    Römers, Luuk H L; Bakker, Charlotte; Dollée, Nathalie; Hoeks, Sanne E; Lima, Alexandre; Raat, Nicolaas J H; Johannes, Tanja; Stolker, Robert J; Mik, Egbert G

    2016-07-01

    Hemodilution is a consequence of fluid replacement during blood loss and is limited by the individual ability to compensate for decreasing hemoglobin level. We tested the ability of a novel noninvasive method for measuring cutaneous mitochondrial PO2 (mitoPO2) to detect this threshold early. Anesthetized and ventilated pigs were hemodynamically monitored and randomized into a hemodilution (n = 12) or a time control (TC) group (n = 14). MitoPO2 measurements were done by oxygen-dependent delayed fluorescence of protoporphyrin IX after preparation of the skin with 20% 5-aminolevulinic acid cream. Tissue oxygen saturation (StO2) was measured with near infrared spectroscopy on the thoracic wall. After baseline measurements, progressive normovolemic hemodilution was performed in the hemodilution group in equal steps (500 ml blood replaced by 500 ml Voluven; Fresenius Kabi AG, Germany). Consecutive measurements were performed after 20-min stabilization periods and repeated 8 times or until the animal died. The TC animals remained stable with regard to hemodynamics and mitoPO2. In the hemodilution group, mitoPO2 became hemoglobin-dependent after reaching a threshold of 2.6 ± 0.2 g/dl. During hemodilution, hemoglobin and mitoPO2 decreased (7.9 ± 0.2 to 2.1 ± 0.2 g/dl; 23.6 ± 2 to 9.9 ± 0.8 mmHg), but StO2 did not. Notably, mitoPO2 dropped quite abruptly (about 39%) at the individual threshold. We observed that this decrease in mitoPO2 occurred at least one hemodilution step before changes in other conventional parameters. Cutaneous mitoPO2 decreased typically one hemodilution step before occurrence of significant alterations in systemic oxygen consumption and lactate levels. This makes mitoPO2 a potential early indicator of the physiologic limit of hemodilution and possibly a physiologic trigger for blood transfusion.

  15. Influence of the depth of sedation on regional cerebral oxygen saturation monitoring in neurosurgery of supratentorial gliomas

    Directory of Open Access Journals (Sweden)

    ZHANG Kai⁃ying

    2012-12-01

    Full Text Available Objective To investigate the influence on regional cerebral oxygen saturation (rScO2 of sedation depth during anesthesia induction and maintenance in supratentorial glioma resections. Methods Thirty patients with Ⅰ - Ⅱ supratentorial glioma (graded by American Society of Anesthesiologists underwent elective supratentorial glioma resection were included in this study. Rocuronium, sufentanil and propofol were used for anesthesia induction. After trachea cannula, total intravenous anesthesia (TIVA was maintained with plasma concentration of propofol 2.80-3.20 μg/ml and remifentanil 0.10-0.20 μg/(kg·min. Thirty groups of rScO2, bispectral index (BIS, mean arterial pressure (MAP and heart rate (HR were recorded continuously till the incision. Results During anesthesia induction, BIS decreased along with the infusion of anesthetics, and there was significant negative correlation between BIS and rScO2 (r = ⁃0.803, P = 0.001. During anesthesia maintenance, rScO2 and BIS were not significantly related (r = 0.147, P = 0.396. Conclusion The rScO2 monitoring can reflect the influence of sedation depth on cerebral oxygen delivery and consumption balance during supratentorial glioma resection under TIVA.

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

    International Nuclear Information System (INIS)

    Morillo, Daniel S; Rojas, Juan L; Crespo, Luis F; León, Antonio; Gross, Nicole

    2009-01-01

    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 (SaO 2 ) signals from overnight pulse oximetry could yield essential information on the diagnosis of sleep apnea hypopnea syndrome (SAHS). SaO 2 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 SD 1 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

  17. 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.

  18. 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.

  19. Projections of climate-driven changes in tuna vertical habitat based on species-specific differences in blood oxygen affinity.

    Science.gov (United States)

    Mislan, K A S; Deutsch, Curtis A; Brill, Richard W; Dunne, John P; Sarmiento, Jorge L

    2017-10-01

    Oxygen concentrations are hypothesized to decrease in many areas of the ocean as a result of anthropogenically driven climate change, resulting in habitat compression for pelagic animals. The oxygen partial pressure, pO 2 , at which blood is 50% saturated (P 50 ) is a measure of blood oxygen affinity and a gauge of the tolerance of animals for low ambient oxygen. Tuna species display a wide range of blood oxygen affinities (i.e., P 50 values) and therefore may be differentially impacted by habitat compression as they make extensive vertical movements to forage on subdaily time scales. To project the effects of end-of-the-century climate change on tuna habitat, we calculate tuna P 50 depths (i.e., the vertical position in the water column at which ambient pO 2 is equal to species-specific blood P 50 values) from 21st century Earth System Model (ESM) projections included in the fifth phase of the Climate Model Intercomparison Project (CMIP5). Overall, we project P 50 depths to shoal, indicating likely habitat compression for tuna species due to climate change. Tunas that will be most impacted by shoaling are Pacific and southern bluefin tunas-habitat compression is projected for the entire geographic range of Pacific bluefin tuna and for the spawning region of southern bluefin tuna. Vertical shifts in P 50 depths will potentially influence resource partitioning among Pacific bluefin, bigeye, yellowfin, and skipjack tunas in the northern subtropical and eastern tropical Pacific Ocean, the Arabian Sea, and the Bay of Bengal. By establishing linkages between tuna physiology and environmental conditions, we provide a mechanistic basis to project the effects of anthropogenic climate change on tuna habitats. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  20. [BEHAVIOR OF HEMOGLOBIN CONCENTRATION, HEMATOCRIT AND OXYGEN SATURATION IN COLOMBIAN UNIVERSITY POPULATION AT DIFFERENT ALTITUDES].

    Science.gov (United States)

    Trompetero González, Andrea Catalina; Cristancho Mejía, Edgar; Benavides Pinzón, William Fernando; Serrato Roa, Mauricio; Landinez Macias, María Paula; Rojas, Joel

    2015-11-01

    the development of this research is base on the growing interest in understanding the adaptations to chronic hipoxia mainly in the range of intermediate altitudes (1 500-3 000 m.s.n.m) and the need to establish parameters of normality in the variables [Hb], Hct and SO2 for diagnostic and characterization of the population purposes. to analyze the behavior of the [Hb], Hct and SaO2 at different intermediate altitudes (970 m.s.n.m, 1 520 m.s.n.m, 1 728 m.s.n.m, 1 923 m.s.n.m, 2 180 m.s.n.m and 2 600 m.s.n.m) in order to contribute to the knowledge of the high altitude physiology and the clinical field to support the diagnosis of anemia. clinically healthy subjects with low levels of physical activity and food consumption report containing iron. Total of 264 participants of both genders between 18 and 30 years. The blood samples were collected from the antecubital vein and the earlobe and analyzed in a radiometer. A non-parametric statistical analysis was performed. with increasing of altitude, [Hb] and Hct values were increased while the SO2 decreased. Men showed higher values than women in [Hb] and Hct, related to lower values of SO2 than women. a threshold variable was not found, perhaps because of the small distance between the altitudes. The values reported were similar but not identical to other studies. This difference could be explained by genetic diversity among populations. this study allows for the first values of characterization of the study population. All altitudes were above the cutoff for the diagnosis of anemia ([Hb] 12 g/dl). Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  1. BLOOD COMPATIBILITY OF 2 DIFFERENT TYPES OF MEMBRANE-OXYGENATOR DURING CARDIOPULMONARY BYPASS IN INFANTS

    NARCIS (Netherlands)

    GU, YJ; BOONSTRA, PW; AKKERMAN, C; MUNGROOP, H; TIGCHELAAR, [No Value; VANOEVEREN, W

    1994-01-01

    The contact of blood with the artificial extracorporeal circuit causes a systemic inflammatory response due to blood activation. In this study, we compared two different paediatric membrane oxygenators used for extracorporeal circulation: a hollow fibre membrane oxygenator (Dideco Masterflo D-701,

  2. Oxygen consumption and blood flow coupling in human motor cortex during intense finger tapping

    DEFF Research Database (Denmark)

    Seyedi Vafaee, Manouchehr; Vang, Kim; Bergersen, Linda H

    2012-01-01

    Rates of cerebral blood flow (CBF) and glucose consumption (CMR(glc)) rise in cerebral cortex during continuous stimulation, while the oxygen-glucose index (OGI) declines as an index of mismatched coupling of oxygen consumption (cerebral metabolic rate of oxygen-CMRO(2)) to CBF and CMR(glc). To t...

  3. 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.

  4. Noninvasive in vivo optical characterization of blood flow and oxygen consumption in the superficial plexus of skin

    Science.gov (United States)

    Liasi, Faezeh Talebi; Samatham, Ravikant; Jacques, Steven L.

    2017-11-01

    Assessing the metabolic activity of a tissue, whether normal, damaged, aged, or pathologic, is useful for diagnosis and evaluating the effects of drugs. This report describes a handheld optical fiber probe that contacts the skin, applies pressure to blanch the superficial vascular plexus of the skin, then releases the pressure to allow refill of the plexus. The optical probe uses white light spectroscopy to record the time dynamics of blanching and refilling. The magnitude and dynamics of changes in blood content and hemoglobin oxygen saturation yield an estimate of the oxygen consumption rate (OCR) in units of attomoles per cell per second. The average value of OCR on nine forearm sites on five subjects was 10±5 (amol/cell/s). This low-cost, portable, rapid, noninvasive optical probe can characterize the OCR of a skin site to assess the metabolic activity of the epidermis or a superficial lesion.

  5. Toward translating near-infrared spectroscopy oxygen saturation data for the non-invasive prediction of spatial and temporal hemodynamics during exercise

    Science.gov (United States)

    Ellwein, Laura; Samyn, Margaret M.; Danduran, Michael; Schindler-Ivens, Sheila; Liebham, Stacy; LaDisa, John F.

    2016-01-01

    Image-based computational fluid dynamics (CFD) studies conducted at rest have shown that atherosclerotic plaque in the thoracic aorta (TA) correlates with adverse wall shear stress (WSS), but there is a paucity of such data under elevated flow conditions. We developed a pedaling exercise protocol to obtain phase contrast magnetic resonance imaging (PC-MRI) blood flow measurements in the TA and brachiocephalic arteries during three-tiered supine pedaling at 130%, 150%, and 170% of resting heart rate (HR), and relate these measurements to noninvasive tissue oxygen saturation (StO2) acquired by near-infrared spectroscopy (NIRS) while conducting the same protocol. Local quantification of WSS indices by CFD revealed low time-averaged WSS on the outer curvature of the ascending aorta and the inner curvature of the descending aorta (dAo) that progressively increased with exercise, but that remained low on the anterior surface of brachiocephalic arteries. High oscillatory WSS observed on the inner curvature of the aorta persisted during exercise as well. Results suggest locally continuous exposure to potentially deleterious indices of WSS despite benefits of exercise. Linear relationships between flow distributions and tissue oxygen extraction calculated from StO2 were found between the left common carotid versus cerebral tissue (r2=0.96) and the dAo versus leg tissue (r2=0.87). A resulting six-step procedure is presented to use NIRS data as a surrogate for exercise PC-MRI when setting boundary conditions for future CFD studies of the TA under simulated exercise conditions. Relationships and ensemble averaged PC-MRI inflow waveforms are provided in an online repository for this purpose. PMID:27376865

  6. 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.

  7. Negative blood oxygen level dependent signals during speech comprehension.

    Science.gov (United States)

    Rodriguez Moreno, Diana; Schiff, Nicholas D; Hirsch, Joy

    2015-05-01

    Speech comprehension studies have generally focused on the isolation and function of regions with positive blood oxygen level dependent (BOLD) signals with respect to a resting baseline. Although regions with negative BOLD signals in comparison to a resting baseline have been reported in language-related tasks, their relationship to regions of positive signals is not fully appreciated. Based on the emerging notion that the negative signals may represent an active function in language tasks, the authors test the hypothesis that negative BOLD signals during receptive language are more associated with comprehension than content-free versions of the same stimuli. Regions associated with comprehension of speech were isolated by comparing responses to passive listening to natural speech to two incomprehensible versions of the same speech: one that was digitally time reversed and one that was muffled by removal of high frequencies. The signal polarity was determined by comparing the BOLD signal during each speech condition to the BOLD signal during a resting baseline. As expected, stimulation-induced positive signals relative to resting baseline were observed in the canonical language areas with varying signal amplitudes for each condition. Negative BOLD responses relative to resting baseline were observed primarily in frontoparietal regions and were specific to the natural speech condition. However, the BOLD signal remained indistinguishable from baseline for the unintelligible speech conditions. Variations in connectivity between brain regions with positive and negative signals were also specifically related to the comprehension of natural speech. These observations of anticorrelated signals related to speech comprehension are consistent with emerging models of cooperative roles represented by BOLD signals of opposite polarity.

  8. 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.

  9. Relationship between muscle oxygenation by NIRS and blood lactate

    International Nuclear Information System (INIS)

    Xu Guodong; Mao Zongzhen; Ye Yanjie; Lv Kunru

    2011-01-01

    The aim of the study was to investigate the relationship of muscle oxygenation in term of oxy-hemoglobin concentration change (ΔHbO 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 ΔHbO 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, ΔHbO 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 ΔHbO 2 and the concurrency of crucial turning points between ΔHbO 2 and BLA was revealed. This relationship between ΔHbO 2 and BLA presented in the increasing load training suggested that ΔHbO 2 might be capable for taking the place of the invasively measured parameter BLA. Considering that ΔHbO 2 can be noninvasively measured by NIRS, ΔHbO 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. A multiplexed electronic architecture for opto-electronic patch sensor to effectively monitor heart rate and oxygen saturation

    Science.gov (United States)

    Yan, Liangwen; Hu, Sijung; Alharbi, Samah; Blanos, Panagiotis

    2018-02-01

    To effectively capture human vital signs, a multi-wavelength optoelectronic patch sensor (MOEPS), together with a schematic architecture of electronics, was developed to overcome the drawbacks of present photoplethysmographic (PPG) sensors. To obtain a better performance of in vivo physiological measurement, the optimal illuminations, i.e., light emitting diodes (LEDs) in the MOEPS, whose wavelength is automatically adjusted to each specific subject, were selected to capture better PPG signals. A multiplexed electronic architecture has been well established to properly drive the MOEPS and effectively capture pulsatile waveforms at rest. The protocol was designed to investigate its performance with the participation of 11 healthy subjects aged between 18 and 30. The signals obtained from green (525nm) and orange (595nm) illuminations were used to extract heart rate (HR) and oxygen saturation (SpO2%). These results were compared with data, simultaneously acquired, from a commercial ECG and a pulse oximeter. Considering the difficulty for current devices to attain the SpO2%, a new computing method, to obtain the value of SpO2%, is proposed depended on the green and orange wavelength illuminations. The values of SpO2% between the MOEPS and the commercial Pulse Oximeter devics showed that the results were in good agreement. The values of HR showed close correlation between commercial devices and the MOEPS (HR: r1=0.994(Green); r2=0.992(Orange); r3=0.975(Red); r4=0.990(IR)).

  11. Low blood flow at onset of moderate-intensity exercise does not limit muscle oxygen uptake

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Mortensen, Stefan P; Saltin, Bengt

    2010-01-01

    The effect of low blood flow at onset of moderate-intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5-min one-legged knee-extensor exercise bout (24 +/- 1 W, mean +/- SD) without (Con) and with (double blockade; DB) arterial infusion...... of inhibitors of nitric oxide synthase (N(G)-monomethyl-l-arginine) and cyclooxygenase (indomethacin) to inhibit the synthesis of nitric oxide and prostanoids, respectively. Leg blood flow and leg oxygen delivery throughout exercise was 25-50% lower (P ... +/- 12 vs. 262 +/- 39 ml/min). The present data demonstrate that muscle blood flow and oxygen delivery can be markedly reduced without affecting muscle oxygen uptake in the initial phase of moderate-intensity exercise, suggesting that blood flow does not limit muscle oxygen uptake at the onset...

  12. Laser Doppler imaging, thermographic imaging, and tissue oxygen saturation measurements detect early skin reactions during breast radiotherapy

    Science.gov (United States)

    Harrison, David K.; Harrison, Eileen M.; Newton, David J.; Windsor, Phyllis M.

    2001-05-01

    A range of acute skin reactions, ranging from mild erythema to moist desquamation, can be seen in patients receiving standard fractionated radiotherapy to the breast for conservation therapy of breast carcinoma. In a number of cases these reactions can cause considerable discomfort and seriously affect the patient's quality of life. In previous studies we have used the techniques of laser Doppler imaging, digital thermographic imaging and lightguide spectrophotometry to study oxygen supply and blood flow in inflammatory reactions induced experimentally in forearm skin. The present study is an attempt to use the same techniques to investigate whether any or all of them can detect changes in breast skin very early on in the course of radiotherapy treatment. A further aim of the longer term study is to investigate to what extent these early changes may be able to predict the occurrence later of severe acute or delayed reactions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Herold, S.

    1985-03-01

    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.

  14. 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.)

  15. Evaluation of Renal Blood Flow and Oxygenation in CKD Using Magnetic Resonance Imaging.

    Science.gov (United States)

    Khatir, Dinah S; Pedersen, Michael; Jespersen, Bente; Buus, Niels H

    2015-09-01

    Animal studies suggest that progression of chronic kidney disease (CKD) is related to renal hypoxia. With renal blood supply determining oxygen delivery and sodium absorption being the main contributor to oxygen consumption, we describe the relationship between renal oxygenation, renal artery blood flow, and sodium absorption in patients with CKD and healthy controls. Cross-sectional study. 62 stable patients with CKD stages 3 to 4 (mean age, 61±13 [SD] years) and 24 age- and sex-matched controls. CKD versus control status. Renal artery blood flow, tissue oxygenation (relative changes in deoxyhemoglobin concentration of the renal medulla [MR2*] and cortex [CR2*]), and sodium absorption. Renal artery blood flow was determined by phase-contrast magnetic resonance imaging (MRI); MR2* and CR2* were determined by blood oxygen level-dependent MRI. Ultrafiltered and reabsorbed sodium were determined from measured glomerular filtration rate (mGFR) and 24-hour urine collections. mGFR in patients was 37% that of controls (36±15 vs 97±23 mL/min/1.73 m(2); P renal artery blood flow was 72% that of controls (319 vs 443 mL/min; P renal artery blood flow or sodium absorption. Increasing arterial blood oxygen tension by breathing 100% oxygen had very small effects on CR2*, but reduced MR2* in both groups. Only renal artery blood flow was determined and thus regional perfusion could not be related to CR2* or MR2*. In CKD, reductions of mGFR and reabsorbed sodium are more than double that of renal artery blood flow, whereas cortical and medullary oxygenation are within the range of healthy persons. Reduction in glomerular filtration fraction may prevent renal hypoxia in CKD. Copyright © 2015 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  16. Low oxygen saturation and severe anemia in compound heterozygous Hb Louisville [β42(CD1)Phe→Leu] and Hb La Desirade [β129(H7)Ala→Val].

    Science.gov (United States)

    Kamseng, Parin; Trakulsrichai, Satariya; Trachoo, Objoon; Yimniam, Walaiporn; Panthan, Bhakbhoom; Jittorntam, Paisan; Niparuck, Pimjai; Sanguanwit, Pitsucha; Wananukul, Winai; Jindadamrongwech, Sumalee

    2017-03-01

    To investigate the cause(s) of a Thai male proband presenting low oxygen saturation by pulse oximetry (SpO 2 ) and severe anemia. As Hb variant was suspected, Hb typing was determined by high-performance liquid chromatography and capillary electrophoresis, and subsequently Hb variant was identified by DNA sequencing. Complete blood counts were performed using automated blood cell counter and oxygen saturation was measured by pulse oximetry. Proband was compound heterozygous for Hb Louisville [β42(CD1)Phe→Leu] and Hb La Desirade [β129(H7)Ala→Val]. Of the proband's two sons, one was compound heterozygous for Hb Louisville and Hb E and the other for Hb La Desirade and Hb E. The former son had similar clinical features and laboratory findings with those of the proband while the latter showed had no abnormal clinical manifestations. This the first report of compound heterozygosity of Hb Louisville and Hb La Desirade in an individual of Southeast Asian ethnicity. Hb variant identification is crucial for genetic counseling and appropriate treatment in regions where hemoglobinopathies are common.

  17. TH-AB-209-05: Validating Hemoglobin Saturation and Dissolved Oxygen in Tumors Using Photoacoustic Computed Tomographic Spectroscopic Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Burnett, J; Sick, J; Liu, B [Purdue University, West Lafayette, IN (United States); Cao, N [University of Washington Medical Center, Seattle, WA (United States); Nakshatri, H; Mendonca, M [Indiana University - Purdue University Indianapolis, Indianapolis, IN (United States); Stantz, K [Purdue University, West Lafayette, IN (United States); Indiana University - Purdue University Indianapolis, Indianapolis, IN (United States)

    2016-06-15

    Purpose: Photoacoustic computed tomographic spectroscopy (PCT-S) provides intra-tumor measurements of oxygenation with high spatial resolution (0.2mm) and temporal fidelity (1–2 minutes) without the need for exogenous agents or ionizing radiation, thus providing a unique in vivo assay to measure SaO{sub 2} and investigate acute and chronic forms of hypoxia. The goal of this study is to validate in vivo SaO{sub 2} levels within tail artery of mice and the relationship between SaO{sub 2} and pO{sub 2} within subcutaneous breast tumors using PCT-S imaging, pulse oximetry and an OxyLite probe. Methods: A closed circuit phantom was fabricated to control blood oxygenation levels, where SaO{sub 2} was measured using a co-oximeter and pO{sub 2} using an Oxylite probe. Next, SaO{sub 2} levels within the tail arteries of mice (n=3) were measured using PCT-S and pulse oximetry while breathing high-to-low oxygen levels (6-cycles). Finally, PCT-S was used to measure SaO{sub 2} levels in MCF-7, MCF-7-VEGF165, and MDA-MB-231 xenograft breast tumors and compared to Oxylite pO{sub 2} levels values. Results: SaO{sub 2} and pO{sub 2} data obtained from the calibration phantom was fit to Hill’s equation: aO{sub 2} levels between 88 and 52% demonstrated a linear relationship (r2=0.96) and a 3.2% uncertainty between PCT-S values relative to pulse oximetry. Scatter plots of localized PCT-S measured SaO2 and Oxylite pO{sub 2} levels in MCF-7/MCF-7-VEGF165 and MDA-MD-231 breast tumors were fit to Hill’s equation: P50=17.2 and 20.7mmHg, and n=1.76 and 1.63. These results are consistent with sigmoidal form of Hill’s equation, where the lower P{sub 50} value is indicative of an acidic tumor microenvironment. Conclusion: The results demonstrate photoacoustic imaging can be used to measure SaO{sub 2} cycling and intra-tumor oxygenation, and provides a powerful in vivo assay to investigate the role of hypoxia in radiation, anti-angiogenic, and immunotherapies.

  18. Closed Loop Control of Oxygen Delivery and Oxygen Generation

    Science.gov (United States)

    2017-08-01

    were used for this study and were connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen...connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen based on the oxygen saturation...2017-4119, 28 Aug 2017. oximetry (SpO2) and intermittent arterial blood sampling for arterial oxygen tension (partial pressure of oxygen [PaO2]) and

  19. Gas exchange efficiency of an oxygenator with integrated pulsatile displacement blood pump for neonatal patients.

    Science.gov (United States)

    Schlanstein, Peter C; Borchardt, Ralf; Mager, Ilona; Schmitz-Rode, Thomas; Steinseifer, Ulrich; Arens, Jutta

    2014-01-01

    Oxygenators have been used in neonatal extracorporeal membrane oxygenation (ECMO) since the 1970s. The need to develop a more effective oxygenator for this patient cohort exists due to their size and blood volume limitations. This study sought to validate the next design iteration of a novel oxygenator for neonatal ECMO with an integrated pulsatile displacement pump, thereby superseding an additional blood pump. Pulsating blood flow within the oxygenator is generated by synchronized active air flow expansion and contraction of integrated silicone pump tubes and hose pinching valves located at the oxygenator inlet and outlet. The current redesign improved upon previous prototypes by optimizing silicone pump tube distribution within the oxygenator fiber bundle; introduction of an oval shaped inner fiber bundle core, and housing; and a higher fiber packing density, all of which in combination reduced the priming volume by about 50% (50 to 27 mL and 41 to 20 mL, respectively). Gas exchange efficiency was tested for two new oxygenators manufactured with different fiber materials: one with coating and one with smaller pore size, both capable of long-term use (OXYPLUS® and CELGARD®). Results demonstrated that the oxygen transfer for both oxygenators was 5.3-24.7 mlO2/min for blood flow ranges of 100-500 mlblood/min. Carbon dioxide transfer for both oxygenators was 3.7-26.3 mlCO2/min for the same blood flow range. These preliminary results validated the oxygenator redesign by demonstrating an increase in packing density and thus in gas transfer, an increase in pumping capacity and a reduction in priming volume.

  20. 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

    2009-01-01

    We examine various independent component analysis (ICA) digital signal processing algorithms for estimating the arterial oxygen saturation (SpO2) as measured by a reflective pulse oximeter. The ICA algorithms examined are FastICA, Maximum Likelihood ICA (ICAML), Molgedey and Schuster ICA (ICAMS......), 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...

  1. Relationship between intraoperative regional cerebral oxygen saturation trends and cognitive decline after total knee replacement: a post-hoc analysis.

    Science.gov (United States)

    Salazar, Fátima; Doñate, Marta; Boget, Teresa; Bogdanovich, Ana; Basora, Misericordia; Torres, Ferran; Gracia, Isabel; Fàbregas, Neus

    2014-01-01

    Bilateral regional brain oxygen saturation (rSO2) trends, reflecting intraoperative brain oxygen imbalance, could warn of brain dysfunction. Various types of cognitive impairment, such as memory decline, alterations in executive function or subjective complaints, have been described three months after surgery. Our aim was to explore the potential utility of rSO2 values as a warning sign for the development of different types of decline in postoperative psychological function. Observational post-hoc analysis of data for the patient sample (n = 125) of a previously conducted clinical trial in patients over the age of 65 years undergoing total knee replacement under spinal anesthesia. Demographic, hemodynamic and bilateral rSO2 intraoperative values were recorded. An absolute rSO2 value of 20% or >25% below baseline were chosen as relevant cutoffs. Composite function test scores were created from baseline to three months for each patient and adjusted for the mean (SD) score changes for a control group (n = 55). Tests were used to assess visual-motor coordination and executive function (VM-EF) (Wechsler Digit Symbol-Coding and Visual Reproduction, Trail Making Test) and memory (Auditory Verbal Learning, Wechsler Memory Scale); scales were used to assess psychological symptoms. We observed no differences in baseline rSO2 values; rSO2 decreased significantly in all patients during surgery (P Left and right rSO2 values were asymmetric in patients who had memory decline (mean [SD] left-right ratio of 95.03 [8.51] vs 101.29 [6.7] for patients with no changes, P = 0.0012). The mean right-left difference in rSO2 was also significant in these patients (-2.87% [4.73%], lower on the right, P = 0.0034). Detection of a trend to asymmetry in rSO2 values can warn of possible postoperative onset of memory decline. Psychological symptoms and memory decline were common three months after knee replacement in our patients over the age of 65 years.

  2. Dependence of diameters and oxygen saturation of retinal vessels on visual field damage and age in primary open-angle glaucoma.

    Science.gov (United States)

    Ramm, Lisa; Jentsch, Susanne; Peters, Sven; Sauer, Lydia; Augsten, Regine; Hammer, Martin

    2016-05-01

    To investigate the interrelationship between the oxygen supply of the retina and its regulation with the severity of primary open-angle glaucoma (POAG). Central retinal artery (CRAE) and vein (CRVE) diameters and oxygen saturation of peripapillary retinal vessels in 41 patients suffering from POAG (64.1 ± 12.9 years) and 40 healthy volunteers (63.6 ± 14.1 years) were measured using the retinal vessel analyzer. All measures were taken before and during flicker light stimulation. The mean retinal nerve fiber layer thickness (RNFLT) was determined by OCT and the visual field mean defect (MD) was identified using perimetry. In glaucoma patients, CRAE (r = -0.48 p = 0.002) and CRVE (r = -0.394 p = 0.014) at baseline were inversely related to MD, while arterial and venous oxygen saturation showed no significant dependence on the severity of the damage. However, the flicker light-induced change in arterio-venous difference in oxygen saturation was correlated with the MD (r = 0.358 p = 0.027). The diameters of arteries and veins at baseline decreased with reduction of the mean RNFLT (arteries: r = 0.718 p field loss, may be explained by a reduction of the retinal metabolic demand with progressive loss of neuronal tissue in glaucoma. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  3. Effects of beach-chair position and induced hypotension on cerebral oxygen saturation in patients undergoing arthroscopic shoulder surgery.

    Science.gov (United States)

    Lee, Jae Hoon; Min, Kyeong Tae; Chun, Yong-Min; Kim, Eun Jung; Choi, Seung Ho

    2011-07-01

    We investigated the effects of the beach-chair position and induced hypotension on regional cerebral oxygen saturation (rSO(2)) in patients undergoing arthroscopic shoulder surgery by using near-infrared spectroscopy. Twenty-eight patients scheduled for arthroscopic shoulder surgery were enrolled prospectively. After induction of anesthesia, mechanical ventilation was controlled to maintain Paco(2) at 35 to 40 mm Hg. Anesthesia was maintained with sevoflurane and remifentanil. After radial artery cannulation, mean arterial pressure (MAP) was measured at the external auditory meatus level and maintained between 60 and 65 mm Hg. The rSO(2) was measured by use of near-infrared spectroscopy. MAP and rSO(2) were recorded at the following times: before induction (T(0)), immediately after induction (T(1) [baseline]), after beach-chair position (T(2)), immediately after induced hypotension (T(3)), 1 hour after induced hypotension (T(4)), and after supine position at the end of surgery (T(5)). Cerebral desaturation was defined as a reduction in rSO(2) to less than 80% of baseline value for 15 seconds or greater. A total of 27 patients were evaluated until the end of this study. The MAP at T(2) was significantly lower than that at T(1). The MAP values at T(3) and T(4) were significantly lower than those at T(1) and T(2). The rSO(2) at T(2) was significantly lower than that at T(1). Unlike the pattern of change in the MAP, there was no additional decrease in rSO(2) at T(3) and T(4). There were 2 patients who had an episode of cerebral desaturation. The beach-chair position combined with induced hypotension significantly decreases rSO(2) in patients undergoing shoulder arthroscopic surgery under general anesthesia. Level IV, study of nonconsecutive patients without consistently applied reference gold standard. Copyright © 2011 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  4. Red blood cell transfusions and tissue oxygenation in anemic hematology outpatients

    NARCIS (Netherlands)

    Yuruk, Koray; Bartels, Sebastiaan A.; Milstein, Dan M. J.; Bezemer, Rick; Biemond, Bart J.; Ince, Can

    2012-01-01

    BACKGROUND: There is little clinical evidence that red blood cell (RBC) transfusions improve oxygen availability at the microcirculatory level. We tested the hypotheses that anemia in chronically anemic patients with relatively healthy microcirculation would be associated with low tissue hemoglobin

  5. Association between regional quadriceps oxygenation and blood oxygen saturation during normoxic one-legged dynamic knee extension

    DEFF Research Database (Denmark)

    Esaki, Kazuki; Hamaoka, Takafumi; Rådegran, Göran

    2005-01-01

    -peak. There was a significant correlation between O(2-NIRS) and S(fv)o2(VL-p: r (2) = 0.62, VL-d: r2 = 0.35, RF-p: r2 = 0.62, with a moderate variation among individuals at each site; residual values = 4.83 - 11.75). These data indicate that NIRS measurement provides a reflection of S(fv)o2 during 20-60% WR-peak of normoxic 1L-KEE....

  6. Effect of blood transfusion on intestinal blood flow and oxygenation in extremely preterm infants during first week of life.

    Science.gov (United States)

    Banerjee, Jayanta; Leung, Terence S; Aladangady, Narendra

    2016-04-01

    Extremely preterm infants receive frequent blood transfusions in the first week of life. The aim of this study was to measure the effect of blood transfusion on intestinal blood flow and oxygenation during the first week of life in extremely preterm infants. Superior mesenteric artery (SMA) peak systolic velocity (PSV) and diastolic velocities were measured 30 to 60 minutes before and after transfusion. Splanchnic tissue hemoglobin index (sTHI), splanchnic tissue oxygenation index (sTOI), and splanchnic fractional tissue oxygen extraction (sFTOE) were measured continuously from 15 to 20 minutes before to after transfusion along with vital variables. Twenty infants were studied (median gestational age, 26 weeks). Ten infants were partially fed (15-68 mL/kg/day). Heart rate and SaO2 remained unaltered; blood pressure increased significantly (p transfusion. Mean SMA PSV (p = 0.63) and diastolic velocity (p = 0.65) remained unaltered. Mean pretransfusion SMA PSV was similar in partially fed (0.78 m/sec) compared to unfed infants (0.52 m/sec; p = 0.06) and the response to transfusion was not dissimilar. There was a significant increase in sTHI (mean difference, 32.3%; p transfusion. There was no significant difference in sTHI or sTOI between fed and unfed infants and their response to transfusion. Blood transfusion increased blood pressure and intestinal tissue oxygenation but did not alter blood flow velocities. Partial feeding had no impact on intestinal blood flow and tissue oxygenation changes. © 2015 AABB.

  7. TRANSFUSION RESTORES BLOOD VISCOSITY AND REINSTATES MICROVASCULAR CONDITIONS FROM HEMORRHAGIC SHOCK INDEPENDENT OF OXYGEN CARRYING CAPACITY

    OpenAIRE

    Cabrales, Pedro; Intaglietta, Marcos; Tsai, Amy G.

    2007-01-01

    Systemic and microvascular hemodynamic responses to transfusion of oxygen using functional and non-functional packed fresh red blood cells (RBCs) from hemorrhagic shock were studied in the hamster window chamber model to determine the significance of RBCs on rheological and oxygen transport properties. Moderate hemorrhagic shock was induced by arterial controlled bleeding of 50% of the blood volume, and a hypovolemic state was maintained for one hour. Volume restitution was performed by infus...

  8. Vagal activity and oxygen saturation response to hypoxia: Effects of aerobic fitness and rating of hypoxia tolerance

    Directory of Open Access Journals (Sweden)

    Tomáš Macoun

    2017-10-01

    Full Text Available Background: A reduction in the inspired oxygen fraction (FiO2 induces a decline in arterial oxygen saturation (SpO2 and changes of heart rate variability (HRV. It has been shown that SpO2 and HRV responses to similar levels of acute normobaric hypoxia are inter-individual variable. Variable response may be influenced by normoxia reached maximal oxygen uptake (VO2max value. Objective: The primary aim was to assess HRV and the SpO2 response to hypoxia, and examine the association with normoxic VO2max. Methods: Supine HRV and SpO2 were monitored during normobaric hypoxia (FiO2 = 9.6% for 10 minutes in 28 subjects, aged 23.7 ± 1.7 years. HRV was evaluated by using both spectral and time domain HRV analysis. Low frequency (LF, 0.05-0.15 Hz and high frequency (HF, 0.15-0.50 Hz power together with square root of the mean of the squares of the successive differences (rMSSD were calculated and transformed by natural logarithm (Ln. Based on the SpO2 in hypoxia, subjects were divided into Resistant (RG, SpO2 ≥ 70.9%, n = 14 and Sensitive (SG, SpO2 < 70.9%, n = 14 groups. Perceived hypoxia tolerance was self-scored on a 4-level scale. Results: VO2max was higher in SG (62.4 ± 7.2 ml ⋅ kg-1 ⋅ min-1 compared with RG (55.5 ± 7.1 ml ⋅ kg-1 ⋅ min-1, p = .017, d = 0.97. A significant relationship (r = -.45, p = .017 between hypoxic-normoxic difference in SpO2 and normoxic VO2max level was found. Vagal activity (Ln rMSSD was significantly decreased (SG: p < .001, d = 2.64; RG: p < .001, d = 1.22, while sympathetic activity (Ln LF/HF was relatively increased (p < .001, d = -1.40 in only the SG during hypoxia. Conclusions: Results show that subjects with a higher aerobic capacity exhibited a greater decline in SpO2, accompanied by greater autonomic cardiac disturbances during hypoxia. The SpO2 reduction was associated with perceived hypoxia comfort/discomfort. The hypoxia

  9. Association between intraoperative tissue oxygenation, arterial blood pressure and noradrenaline use in urological patients

    NARCIS (Netherlands)

    Spruit, R.J.; Schwarte, L.A.; Hakenberg, O.W.; Scheeren, T.

    2011-01-01

    Background and Goal of Study: Inadequate tissue oxygenation should be prevented during surgery as it might cause postoperative morbidity. In this observational study we looked at factors that might influence tissue oxygenation (StO2) such as blood pressure and use of vasoactive drugs. Materials and

  10. Cerebral time domain-NIRS: Reproducibility analysis, optical properties, hemoglobin species and tissue oxygen saturation in a cohort of adult subjects

    OpenAIRE

    Giacalone, Giacomo; Zanoletti, Marta; Contini, Davide; Rebecca, Re; Spinelli, Lorenzo; Roveri, Luisa; Torricelli, Alessandro

    2017-01-01

    The reproducibility of cerebral time-domain near-infrared spectroscopy (TD-NIRS) has not been investigated so far. Besides, reference intervals of cerebral optical properties, of absolute concentrations of deoxygenated-hemoglobin (HbR), oxygenated-hemoglobin (HbO), total hemoglobin (HbT) and tissue oxygen saturation (StO2) and their variability have not been reported. We have addressed these issues on a sample of 88 adult healthy subjects. TD-NIRS measurements at 690, 785, 830 nm were fitted ...

  11. Effect of 2,3-diphosphoglycerate on oxygen affinity of blood in sickle cell anemia

    Science.gov (United States)

    Charache, Samuel; Grisolia, Santiago; Fiedler, Adam J.; Hellegers, Andre E.

    1970-01-01

    Blood of patients with sickle cell anemia (SS) exhibits decreased affinity for oxygen, although the oxygen affinity of hemoglobin S is the same as that of hemoglobin A. SS red cells contain more 2,3-diphosphoglycerate (DPG) than normal erythrocytes. The oxygen affinity of hemolyzed red cells is decreased by added DPG, and hemolysates prepared from SS red cells do not differ from normal hemolysates in this regard. Reduction of oxygen affinity to the levels found in intact SS red cells required DPG concentrations in excess of those found in most SS patients. The same was true of oxygen affinity of patients with pyruvate kinase deficiency. Other organic phosphates, as well as inorganic ions, are known to alter the oxygen affinity of dilute solutions of hemoglobin. These substances, the state of aggregation of hemoglobin molecules, and cytoarchitectural factors probably play roles in determining oxygen affinity of both normal and SS red cells. PMID:5443181

  12. Renal Blood Flow, Glomerular Filtration Rate, and Renal Oxygenation in Early Clinical Septic Shock.

    Science.gov (United States)

    Skytte Larsson, Jenny; Krumbholz, Vitus; Enskog, Anders; Bragadottir, Gudrun; Redfors, Bengt; Ricksten, Sven-Erik

    2018-06-01

    Data on renal hemodynamics, function, and oxygenation in early clinical septic shock are lacking. We therefore measured renal blood flow, glomerular filtration rate, renal oxygen consumption, and oxygenation in patients with early septic shock. Prospective comparative study. General and cardiothoracic ICUs. Patients with norepinephrine-dependent early septic shock (n = 8) were studied within 24 hours after arrival in the ICU and compared with postcardiac surgery patients without acute kidney injury (comparator group, n = 58). None. Data on systemic hemodynamics and renal variables were obtained during two 30-minute periods. Renal blood flow was measured by the infusion clearance of para-aminohippuric acid, corrected for renal extraction of para-aminohippuric acid. Renal filtration fraction was measured by renal extraction of chromium-51 labeled EDTA. Renal oxygenation was estimated from renal oxygen extraction. Renal oxygen delivery (-24%; p = 0.037) and the renal blood flow-to-cardiac index ratio (-21%; p = 0.018) were lower, renal vascular resistance was higher (26%; p = 0.027), whereas renal blood flow tended to be lower (-19%; p = 0.068) in the septic group. Glomerular filtration rate (-32%; p = 0.006) and renal sodium reabsorption (-29%; p = 0.014) were both lower in the septic group. Neither renal filtration fraction nor renal oxygen consumption differed significantly between groups. Renal oxygen extraction was significantly higher in the septic group (28%; p = 0.022). In the septic group, markers of tubular injury were elevated. In early clinical septic shock, renal function was lower, which was accompanied by renal vasoconstriction, a lower renal oxygen delivery, impaired renal oxygenation, and tubular sodium reabsorption at a high oxygen cost compared with controls.

  13. Hypoxemia Episodes during Day and Night and Their Impact on Oxygen Saturation Targeting in Mechanically Ventilated Preterm Infants.

    Science.gov (United States)

    Jain, Deepak; D'Ugard, Carmen; Bello, Jose; Bancalari, Eduardo; Claure, Nelson

    2018-01-01

    Hypoxemia episodes (HE) occur frequently in ventilated preterm infants and hinder the achievement of arterial oxygen saturation (SpO2) targets. These episodes may increase the risk for retinopathy of prematurity and neurodevelopmental disability. There are no data on the variation in HE and SpO2 targeting between day and night. The aim of this study was to evaluate the difference between day and night on the frequency and severity of HE and achievement of SpO2 targets. Twenty-four mechanically ventilated preterm infants with ≥4 episodes of SpO2 day (9 a.m. to 5 p.m.) were compared to the night (9 p.m. to 5 a.m.) for the frequency of HE and proportion of time within and outside the target SpO2 range (90-95%). The frequency of severe HE (SpO2 night compared to the day (1.6 ± 1.0 vs. 2.4 ± 1.3 episodes/h, p = 0.008, and 0.53 ± 0.35 vs. 0.90 ± 0.54 episodes/h, p = 0.018). There was no difference in mean episode duration. The frequency and duration of mild HE (SpO2 night compared to the day (5.9 ± 2.7 vs. 7.1 ± 2.5 episodes/h, p = 0.003, and 72 ± 15 vs. 87 ± 25 s, p = 0.01, respectively). The proportion of time in severe hypoxemia (SpO2 95%) was greater, during the night compared to the day. The mean FiO2 did not differ between day and night. In this group of infants with frequent HE, nighttime was associated with fewer episodes when compared to daytime. This is likely due to less handling and sensory stimulation during the night. The increase in time spent with hyperoxemia during the night is likely to be due to more tolerance of high SpO2 with less proactive weaning of FiO2. © 2017 S. Karger AG, Basel.

  14. 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

  15. Heart Rate and Oxygen Saturation Change Patterns During 6-min Walk Test in Subjects With Chronic Thromboembolic Pulmonary Hypertension.

    Science.gov (United States)

    Inagaki, Takeshi; Terada, Jiro; Yahaba, Misuzu; Kawata, Naoko; Jujo, Takayuki; Nagashima, Kengo; Sakao, Seiichiro; Tanabe, Nobuhiro; Tatsumi, Koichiro

    2017-12-26

    The 6-min walk test (6MWT) is commonly performed to assess functional status in patients with chronic thromboembolic pulmonary hypertension. However, changes in heart rate and oxygen saturation ( S pO 2 ) patterns during 6MWT in patients with chronic thromboembolic pulmonary hypertension remain unclear. Thirty-one subjects with chronic thromboembolic pulmonary hypertension were retrospectively evaluated to examine the relationships between the change in heart rate (Δheart rate), heart rate acceleration time, slope of heart rate acceleration, heart rate recovery during the first minute after 6MWT (HRR1), change in S pO 2 (Δ S pO 2 ), S pO 2 reduction time, and S pO 2 recovery time during 6MWT, and the severity of pulmonary hemodynamics assessed by right heart catheterization and echocardiography. Subjects with severe chronic thromboembolic pulmonary hypertension had significantly longer heart rate acceleration time (144.9 ± 63.9 s vs 96.0 ± 42.5 s, P = .033), lower Δheart rate (47.4 ± 16.9 vs 61.8 ± 13.6 beats, P = .02), and lower HRR1 (13.3 ± 9.0 beats vs 27.1 ± 9.2 beats, P pulmonary hypertension. Subjects with severe chronic thromboembolic pulmonary hypertension also had significantly longer S pO 2 reduction time (178.3 ± 70.3 s vs 134.3 ± 58.4 s, P = .03) and S pO 2 recovery time (107.6 ± 35.3 s vs 69.8 ± 32.7 s, P = .004) than did subjects with mild chronic thromboembolic pulmonary hypertension. Multivariate linear regression analysis showed only mean pulmonary arterial pressure independently was associated with heart rate acceleration time and slope of heart rate acceleration. Heart rate and S pO 2 change patterns during 6MWT is predominantly associated with pulmonary hemodynamics in subjects with chronic thromboembolic pulmonary hypertension. Evaluating heart rate and S pO 2 change patterns during 6MWT may serve a safe and convenient way to follow the change in pulmonary hemodynamics. Copyright © 2017 by Daedalus Enterprises.

  16. Optoacoustic technique for noninvasive monitoring of blood oxygenation: a feasibility study

    Science.gov (United States)

    Esenaliev, Rinat O.; Larina, Irina V.; Larin, Kirill V.; Deyo, Donald J.; Motamedi, Massoud; Prough, Donald S.

    2002-08-01

    Replacement of invasive monitoring of cerebral venous oxygenation with noninvasive techniques offers great promise in the management of life-threatening neurologic illnesses including traumatic brain injury. We developed and built an optoacoustic system to noninvasively monitor cerebral venous oxygenation; the system includes a nanosecond Nd:YAG laser and a specially designed optoacoustic probe. We tested the system in vitro in sheep blood with experimentally varied oxygenation. Our results demonstrated that (1) the amplitude and temporal profile of the optoacoustic waves increase with blood oxygenation in the range from 24% to 92%, (2) optoacoustic signals can be detected despite optical and acoustic attenuation by thick bone, and (3) the system is capable of real-time and continuous measurements. These results suggest that the optoacoustic technique is technically feasible for continuous, noninvasive monitoring of cerebral venous oxygenation.

  17. 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......, and (2) whether blood flow is coupled to oxidative metabolism. 2. Seven individuals performed dynamic plantar flexion from 1 to 9 W. Radial artery and popliteal venous blood were sampled for O2, peritendinous blood flow was determined by 133Xe-washout, calf blood flow by plethysmography, cardiac output...

  18. 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 Lajord

    2013-01-01

    Studies have shown decreased cerebral oxygen metabolism (CMRO(2)) and blood flow (CBF) in patients with cirrhosis with hepatic encephalopathy (HE). It remains unclear, however, whether these disturbances are associated with HE or with cirrhosis itself and how they may relate to arterial blood...... associated with HE rather than the liver disease as such. The changes in CMRO(2) and CBF could not be linked to blood ammonia concentration or CMRA....

  19. 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.

  20. 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.

  1. Oxygen radical-scavenging capacities of peptides from swine blood

    African Journals Online (AJOL)

    USER

    2010-08-02

    Aug 2, 2010 ... ... a basic factor in maintaining life and health (Stadtman and Levine, 2003). ... these problems, peptides from swine blood (PSB) was obtained by the ... (0.05 µm ceramic membrane), ultra-filtration (1000 Da), and spray-drying.

  2. Quantification of modulated blood oxygenation levels in single cerebral veins by investigating their MR signal decay

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacik, Jan [St. Jude Children' s Research Hospital, Memphis, TN (United States). Div. of Translational Imaging Research; University Clinics Jena (Germany). Medical Physics Group; Rauscher, Alexander [University Clinics Jena (Germany). Medical Physics Group; British Columbia Univ., Vancouver (Canada). MRI Research Centre; Reichenbach, Juergen R. [University Clinics Jena (Germany). Medical Physics Group

    2009-07-01

    The transverse magnetization of a single vein and its surrounding tissue is subject to spin dephasing caused by the local magnetic field inhomogeneity which is induced by the very same vessel. This phenomenon can be approximated and simulated by applying the model of an infinitely long and homogeneously magnetized cylinder embedded in a homogeneous tissue background. It is then possible to estimate the oxygenation level of the venous blood by fitting the simulated magnetization-time-course to the measured signal decay. In this work we demonstrate the ability of this approach to quantify the blood oxygenation level (Y) of small cerebral veins in vivo, not only under normal physiologic conditions (Y{sub native}=0.5-0.55) but also during induced changes of physiologic conditions which affect the cerebral venous blood oxygenation level. Changes of blood's oxygenation level induced by carbogen (5% CO{sub 2}, 95% O{sub 2}) and caffeine were observed and quantified, resulting in values of Y{sub carbogen}=0.7 and Y{sub caffeine}=0.42, respectively. The proposed technique may ultimately help to better understand local changes in cerebral physiology during neuronal activation by quantifying blood oxygenation in veins draining active brain areas. It may also be beneficial in clinical applications where it may improve diagnosis of cerebral pathologies as well as monitoring of responses to therapy. (orig.)

  3. The 30-second rule: the effects of prolonged intubation attempts on oxygen saturation and heart rate in preterm infants in the delivery room.

    Science.gov (United States)

    Wozniak, Madeline; Arnell, Kathy; Brown, Melissa; Gonzales, Sarah; Lazarus, Danielle; Rich, Wade; Katheria, Anup

    2018-04-01

    A duration of 30 seconds has been shown to improve the success rate of intubation attempts without any decompensation. There is limited data regarding the detrimental effects of prolonged intubation attempts in preterm infants. The aim was to determine the effect of prolonged intubation attempts on heart rate and oxygen saturation in preterm infants. We retrospectively reviewed videos and physiologic data collected during delivery room (DR) resuscitations. Infants who had a functioning pulse oximeter at the time of intubation in the delivery room were analyzed using video and analog recordings. The duration of the intubation attempt was defined as the time the laryngoscope blade was in the infant's mouth. Prolonged intubations were defined as intubations over 30 seconds. Baseline heart rate and saturations were defined as the heart rate and saturation immediately prior to the intubation attempt. Video recording was used to determine time laryngoscope was in the mouth, what other procedures were performed, and whether there was recovery between attempts. Analog data including heart rate, airway pressure and saturation was also recorded. There were 52 intubation attempts in 28 infants. The median (IQR) birth weight and gestational age were 795 (705, 972) grams and 25 (25, 27) weeks. The duration of an intubation attempt was 35 (27, 46) seconds with number of attempts 2 (1, 2). There were 34 intubation attempts greater than 30 seconds (prolonged group) and 18 attempts less than or equal to 30 seconds (short group). Longer attempts did not affect intubation success (successful 34 [25,37] seconds vs. unsuccessful 41[29, 53] seconds; P=0.05). Infants in the prolonged group had a greater decrease in oxygen saturation percentage from baseline (5±8 percent, short intubation group and 13±27 prolonged intubation group; P=0.004). There was also a significant decrease in heart rate beats per minute between the two groups (6±9 in the short intubation group and 23±29

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

    International Nuclear Information System (INIS)

    Otsuka, Makoto; Ichiya, Yuici; Kuwabara, Yasuo

    1989-01-01

    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)

  5. Image-Based Modeling of Blood Flow and Oxygen Transfer in Feto-Placental Capillaries.

    Directory of Open Access Journals (Sweden)

    Philip Pearce

    Full Text Available During pregnancy, oxygen diffuses from maternal to fetal blood through villous trees in the placenta. In this paper, we simulate blood flow and oxygen transfer in feto-placental capillaries by converting three-dimensional representations of villous and capillary surfaces, reconstructed from confocal laser scanning microscopy, to finite-element meshes, and calculating values of vascular flow resistance and total oxygen transfer. The relationship between the total oxygen transfer rate and the pressure drop through the capillary is shown to be captured across a wide range of pressure drops by physical scaling laws and an upper bound on the oxygen transfer rate. A regression equation is introduced that can be used to estimate the oxygen transfer in a capillary using the vascular resistance. Two techniques for quantifying the effects of statistical variability, experimental uncertainty and pathological placental structure on the calculated properties are then introduced. First, scaling arguments are used to quantify the sensitivity of the model to uncertainties in the geometry and the parameters. Second, the effects of localized dilations in fetal capillaries are investigated using an idealized axisymmetric model, to quantify the possible effect of pathological placental structure on oxygen transfer. The model predicts how, for a fixed pressure drop through a capillary, oxygen transfer is maximized by an optimal width of the dilation. The results could explain the prevalence of fetal hypoxia in cases of delayed villous maturation, a pathology characterized by a lack of the vasculo-syncytial membranes often seen in conjunction with localized capillary dilations.

  6. Oxygen Saturation Surrounding Deep Water Formation Events in the Labrador Sea From Argo-O2 Data

    Science.gov (United States)

    Wolf, Mitchell K.; Hamme, Roberta C.; Gilbert, Denis; Yashayaev, Igor; Thierry, Virginie

    2018-04-01

    Deep water formation supplies oxygen-rich water to the deep sea, spreading throughout the ocean by means of the global thermohaline circulation. Models suggest that dissolved gases in newly formed deep water do not come to equilibrium with the atmosphere. However, direct measurements during wintertime convection are scarce, and the controls over the extent of these disequilibria are poorly quantified. Here we show that, when convection reached deeper than 800 m, oxygen in the Labrador Sea was consistently undersaturated at -6.1% to -7.6% at the end of convection. Deeper convection resulted in greater undersaturation, while convection ending later in the year resulted in values closer to equilibrium, from which we produce a predictive relationship. We use dissolved oxygen data from six profiling Argo floats in the Labrador Sea between 2003 and 2016, allowing direct observations of wintertime convection. Three of the six optode oxygen sensors displayed substantial average in situ drift of -3.03 μmol O2 kg-1 yr-1 (-0.94% O2 yr-1), which we corrected to stable deepwater oxygen values from repeat ship surveys. Observations of low oxygen intrusions during restratification and a simple mixing calculation demonstrate that lateral processes act to lower the oxygen inventory of the central Labrador Sea. This suggests that the Labrador Sea is a net sink for atmospheric oxygen, but uncertainties in parameterizing gas exchange limit our ability to quantify the net uptake. Our results constrain the oxygen concentration of newly formed Labrador Sea Water and allow more precise estimates of oxygen utilization and nutrient regeneration in this water mass.

  7. 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)

    Dobson, M.P.; Leiper, C.A.; Lee, K.; Dixson, H.

    2000-01-01

    Full text: The purpose of this study is to compare oxygen saturation levels (SaO 2 ) 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 SaO 2 . The mean initial SaO 2 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 CO 2 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 SaO 2 during technegas administration. We conclude that oxygen supplied as part of the PVDS system ameliorates the transient reduction in SaO 2 seen during standard Technegas administration. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  8. Barley seed radiosensitivity following post-hydration in oxygen-, nitrogen- and nitrous oxide-saturated water, 1

    International Nuclear Information System (INIS)

    Singh, S.P.; Kesavan, P.C.

    1990-01-01

    Dry (∼3.5 and 4.0 per cent moisture content) barley seeds were exposed to 350 Gy of 60 Co-γ-rays in vacuo and post-hydrated at 4degC for 8 h in O 2 -, N 2 -, or N 2 O-saturated water. The effect of caffeine and t-butyl alcohol (t-BuOH) dissolved in the post-hydration medium on the magnitude of damage developing under these three different gaseous circumstances was studied. The post-irradiation damage and its modification by caffeine and t-BuOH was assessed in terms of 8-day-old seedling injury, peroxidase activity and total peroxides in the 8-day-old seedlings. Post-irradiation O 2 -saturated hydration caused maximal 8-day-old seedling injury, and increased peroxidase activity with concomitant reduction in total peroxides. Both caffeine and t-BuOH afforded significant radioprotection against post-irradiation O 2 -dependent damage. Post-irradiation N 2 O-saturated hydration was even more significantly radioprotective than the N 2 -saturated post-hydration. Under these circumstances, t-BuOH exerted no effect whatsoever on the N 2 - and N 2 O-mediated post-irradiation damage. Caffeine, on the other hand, significantly potentiated these two components of damage. A brief consideration of the physicochemical events which possibly account for the observed effects is presented. (author)

  9. Low blood flow at onset of moderate intensity exercise does not limit muscle oxygen uptake

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Mortensen, Stefan Peter; Saltin, Bengt

    2010-01-01

    The effect of low blood flow at onset of moderate intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5 minute one-legged knee-extensor exercise bout (24+/-1 (+/-S.D.) W) without (CON) and with (double blockade; DB) arterial infusion of i....... Additionally, prostanoids and/or NO appear to play important roles in elevating skeletal muscle blood flow in the initial phase of exercise. Key words: Oxygen delivery, oxygen extraction, nitric oxide, prostanoids.......The effect of low blood flow at onset of moderate intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5 minute one-legged knee-extensor exercise bout (24+/-1 (+/-S.D.) W) without (CON) and with (double blockade; DB) arterial infusion...... of inhibitors of nitric oxide synthase (NOS; L-NMMA) and cyclooxygenase (COX; indomethacin) in order to inhibit the synthesis of nitric oxide (NO) and prostanoids, respectively.. Leg blood flow and leg oxygen delivery throughout exercise was 25-50 % lower (P

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

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Wei-Chiang [School of Oral Hygiene, Taipei Medical University, Taipei 110, Taiwan (China); Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); Chang, Fang-Mo [School of Dentistry, Taipei Medical University, Taipei 110, Taiwan (China); Yang, Tzu-Sen [Master Program in Graduate Institute of Nanomedicine and Medical Engineering, Taipei Medical University, Taipei 110, Taiwan (China); Ou, Keng-Liang [School of Dentistry, Taipei Medical University, Taipei 110, Taiwan (China); Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei 110, Taiwan (China); Department of Dentistry, Taipei Medical University-Shuang-Ho Hospital, Taipei 235, Taiwan (China); Lin, Che-Tong [School of Dentistry, Taipei Medical University, Taipei 110, Taiwan (China); Peng, Pei-Wen, E-mail: apon@tmu.edu.tw [School of Dental Technology, Taipei Medical University, Taipei 110, Taiwan (China)

    2016-11-01

    Titanium dioxide (TiO{sub 2}) 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{sup 4+} chemical state was determined to be present on oxygen-PIII-treated surfaces, which consisted of nanocrystalline TiO{sub 2} 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. - Highlights: • The Ti{sup 4+} chemical state was determined to be present on oxygen-PIII-treated surfaces. • The nanocrystalline TiO{sub 2} with a rutile structure was formed on titanium surfaces. • A nanoporous TiO{sub 2} layer in the rutile phase prepared using oxygen PIII treatment can be used to prolong blood clot formation.

  11. 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.

  12. Limitations of quantitative photoacoustic measurements of blood oxygenation in small vessels

    International Nuclear Information System (INIS)

    Sivaramakrishnan, Mathangi; Maslov, Konstantin; Zhang, Hao F; Stoica, George; Wang, Lihong V

    2007-01-01

    We investigate the feasibility of obtaining accurate quantitative information, such as local blood oxygenation level (sO 2 ), with a spatial resolution of about 50 μm from spectral photoacoustic (PA) measurements. The optical wavelength dependence of the peak values of the PA signals is utilized to obtain the local blood oxygenation level. In our in vitro experimental models, the PA signal amplitude is found to be linearly proportional to the blood optical absorption coefficient when using ultrasonic transducers with central frequencies high enough such that the ultrasonic wavelengths are shorter than the light penetration depth into the blood vessels. For an optical wavelength in the 578-596 nm region, with a transducer central frequency that is above 25 MHz, the sensitivity and accuracy of sO 2 inversion is shown to be better than 4%. The effect of the transducer focal position on the accuracy of quantifying blood oxygenation is found to be negligible. In vivo oxygenation measurements of rat skin microvasculature yield results consistent with those from in vitro studies, although factors specific to in vivo measurements, such as the spectral dependence of tissue optical attenuation, dramatically affect the accuracy of sO 2 quantification in vivo

  13. Corrosion behavior of austenitic and ferritic/martensitic steels in oxygen-saturated liquid Pb-Bi eutectic at 450circC and 550circC

    OpenAIRE

    倉田 有司; 二川 正敏; 斎藤 滋

    2005-01-01

    Static corrosion tests of various austenitic and ferritic/martensitic steels were conducted in oxygen-saturated liquid Pb-Bi at 450circC and 550circC for 3000h to study the effects of temperature and alloying elements on corrosion behavior. Oxidation, grain boundary corrosion, dissolution and penetration were observed. The corrosion depth decreases at 450circC with increasing Cr content in steels regardless of ferritic/martensitic or austenitic steels. Appreciable dissolution of Ni and Cr doe...

  14. 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 (CIs) and P...... 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

  15. 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...

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

    DEFF Research Database (Denmark)

    Hirasawa, Ai; Kaneko, Takahito; Tanaka, Naoki

    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. ...

  17. Intraoperative changes of transcranial Doppler velocity: relation to arterial oxygen content and whole-blood viscosity

    NARCIS (Netherlands)

    Schuurman, P. R.; Albrecht, K. W.

    1999-01-01

    The association of arterial oxygen content (CaO2) and viscosity with transcranial Doppler (TCD) blood flow velocity in the middle cerebral artery was studied in 20 adults without cerebrovascular disease undergoing abdominal surgery associated with significant fluctuations in hematology. TCD

  18. Tulathromycin disturbs blood oxidative and coagulation status | Er ...

    African Journals Online (AJOL)

    ... (white and red blood cells) and arterial blood gas parameters (packed cell volume, ... excess in vitro, oxygen saturation, sodium and potassium) were also determined. Tulathromycin increased (P < 0.05) the levels of malondialdehyde, nitric ...

  19. BLOOD SUBSTITUTES: EVOLUTION FROM NON-CARRYING TO OXYGEN AND GAS CARRYING FLUIDS

    Science.gov (United States)

    Cabrales, Pedro; Intaglietta, Marcos

    2013-01-01

    The development of oxygen (O2) carrying blood substitutes has evolved from the goal of replicating blood O2 transports properties to that of preserving microvascular and organ function, reducing the inherent or potential toxicity of the material used to carry O2, and treating pathologies initiated by anemia and hypoxia. Furthermore, the emphasis has shifted from blood replacement fluid to “O2 therapeutics” that restore tissue oxygenation to specific tissues regions. This review covers the different alternatives, potential and limitations of hemoglobin based O2 carriers (HBOCs) and perfluorocarbon based O2 carriers (PFCOCs), with emphasis on the physiological conditions disturbed in the situation that they will be used. It describes how concepts learned from plasma expanders without O2 carrying capacity can be applied to maintain O2 delivery and summarizes the microvascular responses due to HBOCs and PFCOCs. This review also presents alternative applications of HBOCs and PFCOCs namely: 1) How HBOC O2 affinity can be engineered to target O2 delivery to hypoxic tissues; and 2) How the high gas solubility of PFCOCs provides new opportunities for carrying, dissolving and delivering gases with biological activity. It is concluded that current blood substitutes development has amplified their applications horizon by devising therapeutic functions for oxygen carriers requiring limited O2 delivery capacity restoration. Conversely, full, blood-like O2 carrying capacity re-establishment awaits control of O2 carrier toxicity. PMID:23820271

  20. 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 tension...... decreased gradually to 70% of the control value, indicating hyperventilation. At sea level hyperventilation will not increase brain oxygenation significantly in normal man, as the arterial oxygen content only increases minimally, while CBF is unchanged. At high altitude the beneficial effects...... of acetazolamide on the symptoms of acute mountain sickness may well be due to an improved oxygen supply to the brain, as hyperventilation will, at the low ambient PO2, cause a significant increase of the arterial oxygen content, while CBF presumably is unaffected by the drug. During hypoxia at high altitude...

  1. Cerebral oxygenation in the beach chair position for shoulder surgery in regional anesthesia: impact on cerebral blood flow and neurobehavioral outcome.

    Science.gov (United States)

    Aguirre, José A; Märzendorfer, Olivia; Brada, Muriel; Saporito, Andrea; Borgeat, Alain; Bühler, Philipp

    2016-12-01

    Beach chair position is considered a potential risk factor for central neurological events particularly if combined with low blood pressure. The aim of this study was to assess the impact of regional anesthesia on cerebral blood flow and neurobehavioral outcome. This is a prospective, assessor-blinded observational study evaluating patients in the beach chair position undergoing shoulder surgery under regional anesthesia. University hospital operating room. Forty patients with American Society of Anesthesiologists classes I-II physical status scheduled for elective shoulder surgery. Cerebral saturation and blood flow of the middle cerebral artery were measured prior to anesthesia and continued after beach chair positioning until discharge to the postanesthesia care unit. The anesthesiologist was blinded for these values. Controlled hypotension with systolic blood pressure≤100mm Hg was maintained during surgery. Neurobehavioral tests and values of regional cerebral saturation, bispectral index, the mean maximal blood flow of the middle cerebral artery, and invasive blood pressure were measured prior to regional anesthesia, and measurements were repeated after placement of the patient on the beach chair position and every 20 minutes thereafter until discharge to postanesthesia care unit. The neurobehavioral tests were repeated the day after surgery. The incidence of cerebral desaturation events was 5%. All patients had a significant blood pressure drop 5 minutes after beach chair positioning, measured at the heart as well as the acoustic meatus levels, when compared with baseline values (Psurgery (Pshoulder surgery had no major impact on cerebral blood flow and cerebral oxygenation. However, some impact on neurobehavioral outcome 24 hours after surgery was observed. Copyright © 2016 Elsevier Inc. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gong, G; Yin, Y [Shandong Cancer Hospital, Jinan, Shandong (China)

    2014-06-01

    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.

  3. The influence of external factors on the accuracy of non-invasive measuring of oxygen in blood

    Directory of Open Access Journals (Sweden)

    Y. M. Snizhko

    2016-05-01

    Full Text Available In this paper we investigated a pulse oximetry-based method for mobile devices. This method obtains bio-signals related to blood pulsation in transparent parts of body. The most widely accepted field for use of this method is hospital care. In these cases a pulse oximeter is the best solution for the monitoring of emergency patients. A promising field for pulse oximetry is physical exercise. It only requires simple clips such as ear-clips, finger-clips, headbands etc. However this method presents some difficulties: weak signal, noise ratio, motion artefacts, low perfusion. We used a MAX30100 Oximeter and Heart Rate Sensor integrated circuit to obtain signals of blood pulse waves from red and infrared light emission diodes (LED. This device measures the oxygen saturation of a person’s blood by placing an LED and a photodetector against the thin skin of a person’s body, such as a fingertip, wrist or earlobe. The MAX30100 is a 14-pin surface mount integrated circuit that contains sensors for measuring a person’s heart rate. It can also indirectly determine the oxygen saturation of a person’s blood. The MAX30100 provides a complete pulse oximetry and heart rate measurement solution for medical monitors and wearable fitness devices. As each LED emits light into a person’s finger, the integrated photodetector measures variations in light caused by changes in blood volume. An integrated 16-bit analog to digital converter (ADC with programmable sample rate converts the photodetector output to a digital value. The MAX30100 filters out ambient light that can interfere with an accurate reading. Data are read through a serial I2C interface to computer for further processing. The LED current can be programmed from 0 to 50 mA with proper supply voltage. The LED pulse width can be programmed from 200 µs to 1.6 ms to optimize measurement accuracy and power consumption based on use cases. The SpO2 algorithm is relatively insensitive to the wavelength

  4. 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.

  5. 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.

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

    International Nuclear Information System (INIS)

    Ciobanu, Luisa; Reynaud, Olivier; Le Bihan, Denis; Uhrig, Lynn; Jarraya, Bechir

    2012-01-01

    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 T2'*-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 7 T and 17.2 T under general anesthesia using different anesthetics (isoflurane, ketamine-xylazine, medetomidine). We showed that the brain/vessels contrast in T2'*- weighted images at 17.2 T varied directly according to the applied pharmacological anesthetic agent, a phenomenon that was visible, but to a much smaller extent at 7 T. 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. (authors)

  7. 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

    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...... healthy men (52-76 years). Splanchnic blood flow was measured during hepatic vein catheterization by indirect Fick principle with indocyanine green as the indicator. Splanchnic oxygen uptake was calculated from splanchnic blood flow and the arteriovenous oxygen difference. RESULTS: The meal induced...

  8. Effect of hypoxia on cerebral blood flow regulation during rest and exercise : role of cerebral oxygen delivery on performance

    OpenAIRE

    Fan, J.-L.

    2014-01-01

    Adequate supply of oxygen to the brain is critical for maintaining normal brain function. Severe hypoxia, such as that experienced during high altitude ascent, presents a unique challenge to brain oxygen (O2) supply. During high-intensity exercise, hyperventilation-induced hypocapnia leads to cerebral vasoconstriction, followed by reductions in cerebral blood flow (CBF), oxygen delivery (DO2), and tissue oxygenation. This reduced O2 supply to the brain could potentially account for the reduce...

  9. Influence of partial pressure of oxygen in blood samples on measurement performance in glucose-oxidase-based systems for self-monitoring of blood glucose.

    Science.gov (United States)

    Baumstark, Annette; Schmid, Christina; Pleus, Stefan; Haug, Cornelia; Freckmann, Guido

    2013-11-01

    Partial pressure of oxygen (pO2) in blood samples can affect blood glucose (BG) measurements, particularly in systems that employ the glucose oxidase (GOx) enzyme reaction on test strips. In this study, we assessed the impact of different pO2 values on the performance of five GOx systems and one glucose dehydrogenase (GDH) system. Two of the GOx systems are labeled by the manufacturers to be sensitive to increased blood oxygen content, while the other three GOx systems are not. Aliquots of 20 venous samples were adjusted to the following pO2 values: oxygen sensitive. © 2013 Diabetes Technology Society.

  10. 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...... exhibited lower viscosities than oxygenated samples at low shear rates, whereas the opposite was true at high shear rates. However, blood from cannulated trout had similar viscosities in its deoxygenated and oxygenated states. In the deoxygenated state, addition of adrenaline lowered viscosity at low shear...... rates and increased it at high shear rates, resembling the effects of deoxygenation observed in blood taken by venepuncture. In oxygenated blood on the contrary, no marked adrenaline effects were observed. In deoxygenated blood, addition of cortisol lowered viscosity at all measured shear rates compared...

  11. Zolpidem reduces the blood oxygen level-dependent signal during visual system stimulation

    OpenAIRE

    Licata, Stephanie C.; Lowen, Steven B.; Trksak, George H.; MacLean, Robert R.; Lukas, Scott E.

    2011-01-01

    Zolpidem is a short-acting imidazopyridine hypnotic that binds at the benzodiazepine binding site on specific GABAA receptors to enhance fast inhibitory neurotransmission. The behavioral and receptor pharmacology of zolpidem has been studied extensively, but little is known about its neuronal substrates in vivo. In the present within-subject, double-blind, and placebo-controlled study, blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) at 3 Tesla was used to assess...

  12. New principle for measuring arterial blood oxygenation, enabling motion-robust remote monitoring

    OpenAIRE

    Mark van Gastel; Sander Stuijk; Gerard de Haan

    2016-01-01

    Finger-oximeters are ubiquitously used for patient monitoring in hospitals worldwide. Recently, remote measurement of arterial blood oxygenation (SpO2) with a camera has been demonstrated. Both contact and remote measurements, however, require the subject to remain static for accurate SpO2 values. This is due to the use of the common ratio-of-ratios measurement principle that measures the relative pulsatility at different wavelengths. Since the amplitudes are small, they are easily corrupted ...

  13. Noninvasive diffuse optical monitoring of head and neck tumor blood flow and oxygenation during radiation delivery

    Science.gov (United States)

    Dong, Lixin; Kudrimoti, Mahesh; Cheng, Ran; Shang, Yu; Johnson, Ellis L.; Stevens, Scott D.; Shelton, Brent J.; Yu, Guoqiang

    2012-01-01

    This study explored using a novel diffuse correlation spectroscopy (DCS) flow-oximeter to noninvasively monitor blood flow and oxygenation changes in head and neck tumors during radiation delivery. A fiber-optic probe connected to the DCS flow-oximeter was placed on the surface of the radiologically/clinically involved cervical lymph node. The DCS flow-oximeter in the treatment room was remotely operated by a computer in the control room. From the early measurements, abnormal signals were observed when the optical device was placed in close proximity to the radiation beams. Through phantom tests, the artifacts were shown to be caused by scattered x rays and consequentially avoided by moving the optical device away from the x-ray beams. Eleven patients with head and neck tumors were continually measured once a week over a treatment period of seven weeks, although there were some missing data due to the patient related events. Large inter-patient variations in tumor hemodynamic responses were observed during radiation delivery. A significant increase in tumor blood flow was observed at the first week of treatment, which may be a physiologic response to hypoxia created by radiation oxygen consumption. Only small and insignificant changes were found in tumor blood oxygenation, suggesting that oxygen utilizations in tumors during the short period of fractional radiation deliveries were either minimal or balanced by other effects such as blood flow regulation. Further investigations in a large patient population are needed to correlate the individual hemodynamic responses with the clinical outcomes for determining the prognostic value of optical measurements. PMID:22312579

  14. An applicable approach for extracting human heart rate and oxygen saturation during physical movements using a multi-wavelength illumination optoelectronic sensor system

    Science.gov (United States)

    Alharbi, Samah; Hu, Sijung; Mulvaney, David; Blanos, Panagiotis

    2018-02-01

    The ability to gather physiological parameters such as heart rate (HR) and oxygen saturation (SpO2%) during physical movement allows to continuously monitor personal health status without disrupt their normal daily activities. Photoplethysmography (PPG) based pulse oximetry and similar principle devices are unable to extract the HR and SpO2% reliably during physical movement due to interference in the signals that arise from motion artefacts (MAs). In this research, a flexible reflectance multi-wavelength optoelectronic patch sensor (OEPS) has been developed to overcome the susceptibility of conventional pulse oximetry readings to MAs. The OEPS incorporates light embittered diodes as illumination sources with four different wavelengths, e.g. green, orange, red, and infrared unlike the conventional pulse oximetry devices that normally measure the skin absorption of only two wavelengths (red and infrared). The additional green and orange wavelengths were found to be distinguish to the absorption of deoxyhemoglobin (RHb) and oxyhemoglobin (HbO2). The reliability of extracting physiological parameters from the green and orange wavelengths is due to absorbed near to the surface of the skin, thereby shortening the optical path and so effectively reducing the influence of physical movements. To compensate of MAs, a three-axis accelerometer was used as a reference with help of adaptive filter to reduce MAs. The experiments were performed using 15 healthy subjects aged 20 to 30. The primary results show that there are no significant difference of heart rate and oxygen saturation measurements between commercial devices and OEPS Green (r=0.992), Orange(r=0.984), Red(r=0.952) and IR(r=0.97) and SpO2% (r = 0.982, p = 0.894).

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

    DEFF Research Database (Denmark)

    Lykkedegn, Sine; Sorensen, Grith Lykke; Beck-Nielsen, Signe Sparre

    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

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

    Directory of Open Access Journals (Sweden)

    Sine Lykkedegn

    Full Text Available 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(OHD 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(OHD 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.

  17. Factors associated with blood oxygen partial pressure and carbon dioxide partial pressure regulation during respiratory extracorporeal membrane oxygenation support: data from a swine model.

    Science.gov (United States)

    Park, Marcelo; Mendes, Pedro Vitale; Costa, Eduardo Leite Vieira; Barbosa, Edzangela Vasconcelos Santos; Hirota, Adriana Sayuri; Azevedo, Luciano Cesar Pontes

    2016-01-01

    The aim of this study was to explore the factors associated with blood oxygen partial pressure and carbon dioxide partial pressure. The factors associated with oxygen - and carbon dioxide regulation were investigated in an apneic pig model under veno-venous extracorporeal membrane oxygenation support. A predefined sequence of blood and sweep flows was tested. Oxygenation was mainly associated with extracorporeal membrane oxygenation blood flow (beta coefficient = 0.036mmHg/mL/min), cardiac output (beta coefficient = -11.970mmHg/L/min) and pulmonary shunting (beta coefficient = -0.232mmHg/%). Furthermore, the initial oxygen partial pressure and carbon dioxide partial pressure measurements were also associated with oxygenation, with beta coefficients of 0.160 and 0.442mmHg/mmHg, respectively. Carbon dioxide partial pressure was associated with cardiac output (beta coefficient = 3.578mmHg/L/min), sweep gas flow (beta coefficient = -2.635mmHg/L/min), temperature (beta coefficient = 4.514mmHg/ºC), initial pH (beta coefficient = -66.065mmHg/0.01 unit) and hemoglobin (beta coefficient = 6.635mmHg/g/dL). In conclusion, elevations in blood and sweep gas flows in an apneic veno-venous extracorporeal membrane oxygenation model resulted in an increase in oxygen partial pressure and a reduction in carbon dioxide partial pressure 2, respectively. Furthermore, without the possibility of causal inference, oxygen partial pressure was negatively associated with pulmonary shunting and cardiac output, and carbon dioxide partial pressure was positively associated with cardiac output, core temperature and initial hemoglobin.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Shin; Ujike, Takashi; Kuroki, Soemu; Sakamoto, Shizuki; Soeda, Toshiyuki; Terashi, Akiro; Iio, Masaaki

    1988-10-01

    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 (CMRO/sub 2/) 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 CMRO/sub 2/ 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. Cerebral blood flow and oxygen metabolism in patients with Parkinson's disease

    International Nuclear Information System (INIS)

    Kitamura, Shin; Ujike, Takashi; Kuroki, Soemu; Sakamoto, Shizuki; Soeda, Toshiyuki; Terashi, Akiro; Iio, Masaaki.

    1988-01-01

    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 (CMRO 2 ) 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 CMRO 2 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.)

  20. Cerebral time domain-NIRS: reproducibility analysis, optical properties, hemoglobin species and tissue oxygen saturation in a cohort of adult subjects.

    Science.gov (United States)

    Giacalone, Giacomo; Zanoletti, Marta; Contini, Davide; Re, Rebecca; Spinelli, Lorenzo; Roveri, Luisa; Torricelli, Alessandro

    2017-11-01

    The reproducibility of cerebral time-domain near-infrared spectroscopy (TD-NIRS) has not been investigated so far. Besides, reference intervals of cerebral optical properties, of absolute concentrations of deoxygenated-hemoglobin (HbR), oxygenated-hemoglobin (HbO), total hemoglobin (HbT) and tissue oxygen saturation (StO 2 ) and their variability have not been reported. We have addressed these issues on a sample of 88 adult healthy subjects. TD-NIRS measurements at 690, 785, 830 nm were fitted with the diffusion model for semi-infinite homogenous media. Reproducibility, performed on 3 measurements at 5 minutes intervals, ranges from 1.8 to 6.9% for each of the hemoglobin species. The mean ± SD global values of HbR, HbO, HbT, StO 2 are respectively 24 ± 7 μM, 33.3 ± 9.5 μM, 57.4 ± 15.8 μM, 58 ± 4.2%. StO 2 displays the narrowest range of variability across brain regions.

  1. Neonatal oxidative stress depends on oxygen blood pressure in umbilical artery.

    Science.gov (United States)

    Proietti, F; De Bernardo, G; Longini, M; Sordino, D; Scaramuzzini, G; Tataranno, M L; Belvisi, E; Bazzini, F; Perrone, S; Buonocore, G

    2016-01-01

    With advancing gestation, partial pressure of oxygen (pO2) and pH fall significantly. Hypoxia is a main factor inducing free radical generation and thereby oxidative stress (OS). Placental and fetal tissue response when oxygen becomes restricted is complex and partially known. We tested the hypothesis that changes in umbilical artery and vein blood gas concentrations modulate OS occurrence in the newborn. Seventy umbilical artery and vein plasma samples were collected from healthy term newborns immediately after delivery. F2 Isoprostanes (F2-Isop) were measured in all samples as reliable markers of lipid peroxidation. Significantly lower pCO2 and higher pO2 and pH were found in umbilical vein than in artery, as expected. A positive correlation was detected between pH and pO2 only in umbilical artery (p=0.019). F2-Isop levels were no different between artery and vein in cord blood. Significant correlations were found between F2-Isop and pCO2 (p=0.025) as well as between F2-Isop and pH in umbilical vein (p=0.027). F2-Isop correlated with pCO2 (p=0.007) as well as with pO2 values (p=0.005) in umbilical artery blood. Oxidative stress (OS) in newborns depends on oxygen concentrations in umbilical artery. OS biomarkers significantly correlate with pO2 and in umbilical artery but not in umbilical vein. In normoxic conditions fetal-maternal gas exchanges occurring in placenta re-establish normal higher oxygen levels in umbilical vein than artery, with a normal production of free radicals without any deleterious effects.

  2. Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia

    Energy Technology Data Exchange (ETDEWEB)

    Clanet, M

    1987-06-18

    Studies of experimentally-induced ischaemia have shown that the intensity of neuronal suffering is related to the fall in perfusion rate. Below a certain level, called functional threshold, cerebral function is reversibly altered, whereas at a lower level (tissue necrosis threshold) the damage inflicted on neurons is irreversible. Between these two thresholds lies a ''penumbra zone''. This concept of thresholds must be mitigated by 2 parameters: duration of ischaemia and selective vulnerability of the various structures affected. Variations in blood flow rate only indirectly affect the state of tissues. Techniques developed from positron emission tomography make it possible to evaluate the metabolic activity of brain tissue in vivo: oxygen consumption (CMRO/sub 2/), oxygen extraction (EO/sub 2/) and glucose consumption (CMRG) which are thus correlated to cerebral blood flow and cerebral blood volume, sometimes also to tissue pH. Normal relations between blood flow rate and metabolism may be altered. Misery perfusion reflects a fall in cerebral blood flow with an increase in EO/sub 2/ and often a decrease in CMRO/sub 2/, whereas luxury perfusion reflects an increase in cerebral blood flow rate with reduction of CMRO/sub 2/, EO/sub 2/ and CMRG. The type of alteration encountered in human ischaemia varies according to the nature of the accident: studies of transient accidents emphasize the different haemodynamic aspects of occlusion of the wider arteries. The metabolic and haemodynamic profiles of established ischaemic accidents vary according to their type and to the time of the study, reflecting the complexity of the physiopathological mechanisms involved; they are frequently associated with metabolic repercussions at a distance from the ischaemic focus, which supports the concept of diaschisis.

  3. Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia

    International Nuclear Information System (INIS)

    Clanet, M.

    1987-01-01

    Studies of experimentally-induced ischaemia have shown that the intensity of neuronal suffering is related to the fall in perfusion rate. Below a certain level, called functional threshold, cerebral function is reversibly altered, whereas at a lower level (tissue necrosis threshold) the damage inflicted on neurons is irreversible. Between these two thresholds lies a ''penumbra zone''. This concept of thresholds must be mitigated by 2 parameters: duration of ischaemia and selective vulnerability of the various structures affected. Variations in blood flow rate only indirectly affect the state of tissues. Techniques developed from positron emission tomography make it possible to evaluate the metabolic activity of brain tissue in vivo: oxygen consumption (CMRO 2 ), oxygen extraction (EO 2 ) and glucose consumption (CMRG) which are thus correlated to cerebral blood flow and cerebral blood volume, sometimes also to tissue pH. Normal relations between blood flow rate and metabolism may be altered. Misery perfusion reflects a fall in cerebral blood flow with an increase in EO 2 and often a decrease in CMRO 2 , whereas luxury perfusion reflects an increase in cerebral blood flow rate with reduction of CMRO 2 , EO 2 and CMRG. The type of alteration encountered in human ischaemia varies according to the nature of the accident: studies of transient accidents emphasize the different haemodynamic aspects of occlusion of the wider arteries. The metabolic and haemodynamic profiles of established ischaemic accidents vary according to their type and to the time of the study, reflecting the complexity of the physiopathological mechanisms involved; they are frequently associated with metabolic repercussions at a distance from the ischaemic focus, which supports the concept of diaschisis [fr

  4. Regional cerebral blood flow and oxygen metabolism in normal pressure hydrocephalus after subarachnoid hemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Masatsune; Kikuchi, Haruhiko; Taki, Waro; Kobayashi, Akira; Nishizawa, Sadahiko; Yonekura, Yoshiharu; Konishi, Junji [Kyoto Univ. (Japan). Faculty of Medicine

    1989-05-01

    To clarify the pathophysiology of normal pressure hydrocephalus (NPH) after subarachnoid hemorrhage, the authors measured cerebral blood flow (CBF), cerebral oxygen metabolic rates (CMRO{sub 2}), the cerebral oxygen extraction fraction (OEF), and cerebral blood volume (CBV) in eight normal volunteers, six SAH patients with NPH, and seven patients without NPH by {sup 15}O-labeled gas and positron emission tomography (PET). In the NPH group, PET revealed a decrease in CBF in the lower regions of the cerebral cortex and a diffuse decrease in CMRO{sub 2}. The decrease in CBF in the lower frontal, temporal, and occipital cortices was significantly greater in the NPH than in the non-NPH group. Reduction of CMRO{sub 2} was also more extensive in the NPH group, and both CBF and CMRO{sub 2} were more markedly decreased in the lower frontal region. OEF was increased in all areas in both of the patient groups, but the increase was not significant in most areas. CBF, CMRO{sub 2} and OEF did not significantly differ between the non-NPH group and the normal volunteers. There was no significant difference in CBV among the three groups. These results indicate that NPH involves impairment of cerebral oxygen metabolism in the lower regions of the cerebral cortex, particularly in the lower frontal region. (author).

  5. Comparison of extracapillary and endocapillary blood flow oxygenators for open heart surgery in dogs: efficiency of gas exchange and platelet conservation.

    Science.gov (United States)

    Hoshi, Katsuichiro; Tanaka, Ryou; Shibazaki, Akira; Nagashima, Yukiko; Hirao, Hidehiro; Namiki, Ryosuke; Takashima, Kazuaki; Noishiki, Yasuharu; Yamane, Yoshihisa

    2003-03-01

    The goal of the current study was to compare the efficiency of gas exchange and platelet conservation of a new extracapillary blood flow oxygenator versus an endocapillary blood flow oxygenator during open heart surgery with extracorporeal circulation in dogs. Dilation and remodeling of the right ventricular outflow tract of dogs was performed using a patch graft technique to simulate pulmonary stenosis. Sequential pre- and post-operative blood analysis revealed that gas exchange efficiency and platelet conservation was significantly greater with the extracapillary blood flow oxygenator than with the endocapillary blood flow oxygenator. However, the priming volume of the extracapillary blood flow oxygenator was significantly greater, leading to hemodilution. We conclude that while the extracapillary blood flow oxygenator provided benefits in terms of gas exchange and platelet conservation, development of a smaller extracapillary blood flow type oxygenator to reduce hemodilution effects would be beneficial.

  6. [Values of mixed venous oxygen saturation and difference of mixed venous-arterial partial pressure of carbon dioxide in monitoring of oxygen metabolism and treatment after open-heart operation].

    Science.gov (United States)

    Pan, Chuanliang; Zhang, Haiying; Liu, Jianping

    2014-10-01

    To explore the clinic values of early goal directed treatment (EGDT) with the target of mixed venous oxygen saturation (SvO₂) and difference of mixed venous-arterial partial pressure of carbon dioxide (Pv-aCO₂) in monitoring of oxygen metabolism and treatment for patients post open-heart operation. A prospective study was conducted. The adult patients admitted to Third People's Hospital of Chengdu from December 2011 to March 2014 with SvO₂2 mmol/L when admitted in intensive care unit (ICU) were selected on whom elective open-heart operation and pulmonary artery catheter examination were done. All patients received EGDT with the target of SvO₂≥0.65 and Pv-aCO₂<6 mmHg (1 mmHg=0.133 kPa) and were divided into three groups by the values of SvO₂and Pv-aCO₂at 6-hour after ICU admission: A group with SvO₂≥0.65 and Pv-aCO₂<6 mmHg, B group with SvO₂≥0.65 and Pv-aCO₂≥6 mmHg, and C group with SvO₂<0.65. Then the changes and prognosis of the patients in different groups were observed. 103 cases were included, 44 in A group, 31 in B group and 28 in C group. The acute physiology and chronic health evaluation II (APACHEII) score in group A were significantly lower than that in group B or C at 6, 24, 48 and 72 hours (T6, T24, T48, T72) of ICU admission (T6: 11.4 ± 5.8 vs. 13.9 ± 5.4, 13.7 ± 6.4; T24: 8.8 ± 3.7 vs. 10.8 ± 4.8, 11.8 ± 5.4; T48: 8.7 ± 4.1 vs. 9.6 ± 4.2, 10.2 ± 5.1; T72: 7.5 ± 3.4 vs. 8.6 ± 2.9, 9.2 ± 4.2, all P<0.05), and the sequential organ failure assessment (SOFA) showed the same tendency (T6: 6.5 ± 4.3 vs. 8.0 ± 3.8, 9.1 ± 4.5; T24: 6.6 ±3.6 vs. 8.6 ± 3.9, 8.5 ± 3.3; T48: 5.2 ± 3.4 vs. 7.0 ± 3.6, 7.6 ± 5.1; T72: 4.6 ± 2.4 vs. 5.8 ± 2.5, 6.8 ± 3.5, all P<0.05). The values of blood lactic acid (mmol/L) in group A and B were significant lower than that in group C at T6, T24, T48 and T72 (T6: 1.60 ± 0.95, 2.20 ± 1.02 vs. 2.55 ± 1.39; T24: 2.26 ± 1.26, 2.70 ± 1.36 vs. 3.34 ± 2.36; T48: 2.01 ± 1.15, 2.17

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

    International Nuclear Information System (INIS)

    Baron, J.C.; Lebrun-Grandie, P.; Serdaru, M.; Bousser, M.G.; Lhermitte, F.; Cabanis, E.

    1982-09-01

    This work gives the results of a study by positron emission tomography of the cerebral blood flow (CBF), oxygen-extraction rate (O 2 E) and oxygen consumption (CMRO 2 ) 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 O 2 E (''luxury perfusion'') and especially preservation of the CMRO 2 suggesting a decoupling not only between CBF and CMRO 2 but also between CMRO 2 and functional state of the tissue. Some time after the attack a new study showed the recoupling between CBF and CMRO 2 , 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 [fr

  8. Changes in hemoglobin-oxygen affinity with shape variations of red blood cells

    Science.gov (United States)

    Chowdhury, Aniket; Dasgupta, Raktim; Majumder, Shovan K.

    2017-10-01

    Shape variations of red blood cells (RBCs) are known to occur upon exposure to various drugs or under diseased conditions. The commonly observed discocytic RBCs can be transformed to echinocytic or stomatocytic shape under such conditions. Raman spectra of the three major shape variations, namely discocyte, echinocyte, and stomatocyte, of RBCs were studied while subjecting the cells to oxygenated and deoxygenated conditions. Analysis of the recorded spectra suggests an increased level of hemoglobin (Hb)-oxygen affinity for the echinocytes. Also, some level of Hb degradation could be noticed for the deoxygenated echinocytes. The effects may arise from a reduced level of intracellular adenosine triphosphate in echinocytic cells and an increased fraction of submembrane Hb.

  9. 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...... 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...... at higher workloads in T2DM patients and their work capacity and increase in cardiac output were only ~80% of that established in the control subjects. CBF and cerebral oxygenation were reduced during exercise in T2DM patients (P

  10. Tackling the Saturation of Oxygen: The Use of Phosphorus and Sulfur as Proxies within the Neutral Interstellar Medium of Star-forming Galaxies

    Science.gov (United States)

    James, B.; Aloisi, A.

    2018-02-01

    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, as the only O I line available within the Hubble Space Telescope (HST) UV wavelength range (1150–3200 Å) is often saturated. As such, proxies for oxygen are needed to indirectly derive 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, P II and S II, within more typical star-forming environments. Using HST-Cosmic Origins Spectrograph (COS) far-UV (FUV) spectra of a sample of nearby star-forming galaxies (SFGs) and the oxygen abundances in their ionized gas, we demonstrate that both P and S are mildly depleted with respect to O and follow a trend, log(P II/S II) = -1.73 +/- 0.18, in excellent agreement with the solar ratio of {log}{({{P}}/{{S}})}ȯ =-1.71 +/- 0.04 over the large range of metallicities (0.03–3.2 Z ⊙) and H I column densities ({log}[N(H I)/cm‑2] =18.44–21.28) spanned by the sample. From literature data we show evidence that both elements individually trace oxygen according to their respective solar ratios across a wide range of environments. Our findings demonst-rate that the solar ratios of {log}{({{P}}/{{O}})}ȯ =-3.28+/- 0.06 and {log}{({{S}}/{{O}})}ȯ =-1.57+/- 0.06 can both be used to derive reliable O/H abundances in the neutral gas of local and high-redshift SFGs. The difference between O/H in the ionized- and neutral gas phases is studied with respect to metallicity and H I content. The observed trends are consistent with galactic outflows and/or star formation inefficiency affecting the most metal-poor galaxies, with the possibility of primordial gas accretion at all metallicities.

  11. Interplay of crystal fractionation, sulfide saturation and oxygen fugacity on the iron isotope composition of arc lavas: An example from the Marianas

    Science.gov (United States)

    Williams, H. M.; Prytulak, J.; Woodhead, J. D.; Kelley, K. A.; Brounce, M.; Plank, T.

    2018-04-01

    Subduction zone systems are central to a multitude of processes from the evolution of the continental crust to the concentration of metals into economically viable deposits. The interplay between oxygen fugacity, sulfur saturation, fluid exsolution and fractionating mineral assemblages that gives rise to typical arc magma chemical signatures is, however, still poorly understood and novel geochemical approaches are required to make further progress. Here we examine a well-characterized suite of arc lavas from the Marianas (W. Pacific) for their stable Fe isotope composition. In agreement with previous work and mass balance considerations, contributions from sediments and/or fluids are shown to have negligible effect on Fe isotopes. Instead, we focus on disentangling processes occurring during basalt through dacite differentiation using a sample suite from the island of Anatahan. Anatahan whole rock Fe isotope compositions (δ57Fe) range from -0.05 ± 0.05 to 0.17 ± 0.03 (2 S.D.)‰. A fractionation model is constructed, where three distinct stages of differentiation are required to satisfy the combined major and trace element and isotopic observations. In particular, the sequestration of isotopically heavy Fe into magnetite and isotopically light Fe into sulfide melts yields important constraints. The data require that lavas are first undersaturated with respect to crystalline or molten sulfide, followed by the crystallisation of magnetite, which then triggers late sulfide saturation. The model demonstrates that the final stage of removal of liquid or crystalline sulfide can effectively sequester Cu (and presumably other chalcophiles) and that late stage exsolution of magmatic fluids or brines may not be required to do this, although these processes are not mutually exclusive. Finally, the new Fe isotope data are combined with previous Tl-Mo-V stable isotope determinations on the same samples. Importantly, the multi-valent transition metal stable isotope systems of

  12. Differences in prefrontal blood oxygenation during an acute multitasking stressor in ecstasy polydrug users.

    Science.gov (United States)

    Roberts, C A; Wetherell, M A; Fisk, J E; Montgomery, C

    2015-01-01

    Cognitive deficits are well documented in ecstasy (3,4-methylenedioxymethamphetamine; MDMA) users, with such deficits being taken as evidence of dysregulation of the serotonin (5-hydroxytryptamine; 5-HT) system. More recently neuroimaging has been used to corroborate these deficits. The present study aimed to assess multitasking performance in ecstasy polydrug users, polydrug users and drug-naive individuals. It was predicted that ecstasy polydrug users would perform worse than non-users on the behavioural measure and this would be supported by differences in cortical blood oxygenation. In the study, 20 ecstasy-polydrug users, 17 polydrug users and 19 drug-naive individuals took part. On day 1, drug use history was taken and questionnaire measures were completed. On day 2, participants completed a 20-min multitasking stressor while brain blood oxygenation was measured using functional near infrared spectroscopy (fNIRS). There were no significant differences between the three groups on the subscales of the multitasking stressor. In addition, there were no significant differences on self-report measures of perceived workload (NASA Task Load Index). In terms of mood, ecstasy users were significantly less calm and less relaxed compared with drug-naive controls. There were also significant differences at three voxels on the fNIRS, indicating decreased blood oxygenation in ecstasy users compared with drug-naive controls at voxel 2 (left dorsolateral prefrontal cortex), voxel 14 and voxel 16 (right dorsolateral prefrontal cortex), and compared with polydrug controls at V14. The results of the present study provide support for changes in brain activation during performance of demanding tasks in ecstasy polydrug users, which could be related to cerebral vasoconstriction.

  13. Some problems of treating acute arterial obstruction using hyperbaric oxygenation ultraviolet irradiation of blood and hemosorption

    International Nuclear Information System (INIS)

    Karyakin, A.M.

    1988-01-01

    Up-to-date state of the problem of acute arterial obstruction (AAO) is considered and clinical observations of patients with acute emboli and thrombosis of abdominal aorta and main arteries of lower extremitics are analyzed. Complex of detoxication therapy and measures on controlling AAO in patients during postoperation period is presented. Complex application of hemosorption, ultraviolet irradiation of autoblood and hyperbaric oxygenation enabled to achieve correction of some indices. Reliable evidences of high therapeutic efficiency of combined application of mentioned methods to patients with reconstructed blood flow are presented. 38 refs.; 3 tabs

  14. Arterial Spin Labeling and Blood Oxygen Level-Dependent MRI Cerebrovascular Reactivity in Cerebrovascular Disease

    DEFF Research Database (Denmark)

    Smeeing, Diederik P J; Hendrikse, Jeroen; Petersen, Esben T

    2016-01-01

    BACKGROUND: The cerebrovascular reactivity (CVR) results of blood oxygen level-dependent (BOLD) and arterial spin labeling (ASL) MRI studies performed in patients with cerebrovascular disease (steno-occlusive vascular disease or stroke) were systematically reviewed. SUMMARY: Thirty-one articles...... found a significant lower ASL CVR in the ipsilateral hemispheres of patients compared to controls. KEY MESSAGES: This review brings support for a reduced BOLD and ASL CVR in the ipsilateral hemisphere of patients with cerebrovascular disease. We suggest that future studies will be performed in a uniform...... way so reference values can be established and could be used to guide treatment decisions in patients with cerebrovascular disease....

  15. Three-dimensional multispectral optoacoustic mesoscopy reveals melanin and blood oxygenation in human skin in vivo.

    Science.gov (United States)

    Schwarz, Mathias; Buehler, Andreas; Aguirre, Juan; Ntziachristos, Vasilis

    2016-01-01

    Optical imaging plays a major role in disease detection in dermatology. However, current optical methods are limited by lack of three-dimensional detection of pathophysiological parameters within skin. It was recently shown that single-wavelength optoacoustic (photoacoustic) mesoscopy resolves skin morphology, i.e. melanin and blood vessels within epidermis and dermis. In this work we employed illumination at multiple wavelengths for enabling three-dimensional multispectral optoacoustic mesoscopy (MSOM) of natural chromophores in human skin in vivo operating at 15-125 MHz. We employ a per-pulse tunable laser to inherently co-register spectral datasets, and reveal previously undisclosed insights of melanin, and blood oxygenation in human skin. We further reveal broadband absorption spectra of specific skin compartments. We discuss the potential of MSOM for label-free visualization of physiological biomarkers in skin in vivo. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. 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

    -blocker metoprolol). At baseline and following 18 months of therapy we determined forearm resistance by venous occlusion plethysmography. Using magnetic resonance imaging (MRI) renal artery blood flow was measured for calculation of RVR, and blood oxygen level dependent (BOLD) MRI was used as a marker of renal...

  17. Blood transfusion improves renal oxygenation and renal function in sepsis-induced acute kidney injury in rats

    NARCIS (Netherlands)

    L. Zafrani (Lara); B. Ergin (Bulent); Kapucu, A. (Aysegul); C. Ince (Can)

    2016-01-01

    textabstractBackground: The effects of blood transfusion on renal microcirculation during sepsis are unknown. This study aimed to investigate the effect of blood transfusion on renal microvascular oxygenation and renal function during sepsis-induced acute kidney injury. Methods: Twenty-seven Wistar

  18. Blood transfusion improves renal oxygenation and renal function in sepsis-induced acute kidney injury in rats

    NARCIS (Netherlands)

    Zafrani, Lara; Ergin, Bulent; Kapucu, Aysegul; Ince, Can

    2016-01-01

    The effects of blood transfusion on renal microcirculation during sepsis are unknown. This study aimed to investigate the effect of blood transfusion on renal microvascular oxygenation and renal function during sepsis-induced acute kidney injury. Twenty-seven Wistar albino rats were randomized into

  19. Healthy Dental Pulp Oxygen Saturation Rates in Subjects with Homozygous Sickle Cell Anemia: A Cross-Sectional Study Nested in a Cohort.

    Science.gov (United States)

    Souza, Soraia de Fátima Carvalho; Thomaz, Erika Bárbara Abreu Fonseca; Costa, Cyrene Piazera Silva

    2017-12-01

    To compare the percentage of arterial oxygen saturation (SpO 2 ) in healthy teeth with confirmed pulp vitality between individuals with sickle cell anemia (HbSS) and normal hemoglobin A (HbAA). This is a cross-sectional study nested within a cohort. Samples (n = 2543) comprised teeth with intact crowns and pulp vitality confirmed by thermal sensitivity tests and no history of caries, periodontal disease, or dental trauma. A total of 728 teeth of 113 individuals with HbSS and 1815 teeth of 246 individuals with HbAA were evaluated. Data analysis was performed using the χ 2 and Mann-Whitney tests and Spearman correlation analysis (α = 0.05). The study groups were comparable in terms of age, race, and sex (P > .05). Subjects with HbSS exhibited lower median SpO 2 levels in the body and upper teeth, excluding canines, than subjects with HbAA (P  .05). Compared with individuals with HbAA, those with HbSS exhibited lower SpO 2 in maxillary teeth with confirmed pulp vitality, except in the canines. There was no correlation between SpO 2 levels of the body and dental pulp in individuals with HbSS or HbAA. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  20. Combining central venous-to-arterial partial pressure of carbon dioxide difference and central venous oxygen saturation to guide resuscitation in septic shock.

    Science.gov (United States)

    Du, Wei; Liu, Da-Wei; Wang, Xiao-Ting; Long, Yun; Chai, Wen-Zhao; Zhou, Xiang; Rui, Xi

    2013-12-01

    Central venous oxygen saturation (Scvo2) is a useful therapeutic target when treating septic shock. We hypothesized that combining Scvo2 and central venous-to-arterial partial pressure of carbon dioxide difference (△Pco2) may provide additional information about survival. We performed a retrospective analysis of 172 patients treated for septic shock. All patients were treated using goal-directed therapy to achieve Scvo2 ≥ 70%. After 6 hours of treatment, we divided patients into 4 groups based on Scvo2 (<70% or ≥ 70%) and △Pco2 (<6 mm Hg or ≥ 6 mm Hg). Overall, 28-day mortality was 35.5%. For patients in whom the Scvo2 target was not achieved at 6 hours, mortality was 50.0%, compared with 29.5% in those in whom Scvo2 exceeded 70% (P = .009). In patients with Scvo2 ≥ 70%, mortality was lower if △Pco2 was <6 mm Hg than if △Pco2 was ≥ 6 mm Hg (56.1% vs 16.1%, respectively; P < .001) and 6-hour lactate clearance was superior (0.01 ± 0.61 vs 0.21 ± 0.31, respectively; P = .016). The combination of Scvo2 and △Pco2 appears to predict outcome in critically ill patients resuscitated from septic shock better than Scvo2 alone. Patients who meet both targets appear to clear lactate more efficiently. © 2013.

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

    International Nuclear Information System (INIS)

    Acosta-Elias, M.; Sarabia-Sainz, A.; Silva-Campa, E.; Angulo-Molina, A.; Soto-Puebla, D.; Barboza-Flores, M.; Melendrez, R.; Alvarez-Garcia, S.; Pedroza-Montero, M.; Pedroso-Santana, S.; Santacruz-Gomez, K.; Castaneda, B.

    2015-01-01

    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)

  2. 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)

  3. Prefrontal oxygenation correlates to the responses in facial skin blood flows during exposure to pleasantly charged movie

    OpenAIRE

    Matsukawa, Kanji; Endo, Kana; Asahara, Ryota; Yoshikawa, Miho; Kusunoki, Shinya; Ishida, Tomoko

    2017-01-01

    Abstract Our laboratory reported that facial skin blood flow may serve as a sensitive tool to assess an emotional status. Cerebral neural correlates during emotional interventions should be sought in relation to the changes in facial skin blood flow. To test the hypothesis that prefrontal activity has positive relation to the changes in facial skin blood flow during emotionally charged stimulation, we examined the dynamic changes in prefrontal oxygenation (with near‐infrared spectroscopy) and...

  4. Effects of exercise training on calf muscle oxygen extraction and blood flow in patients with peripheral artery disease.

    Science.gov (United States)

    Baker, Wesley B; Li, Zhe; Schenkel, Steven S; Chandra, Malavika; Busch, David R; Englund, Erin K; Schmitz, Kathryn H; Yodh, Arjun G; Floyd, Thomas F; Mohler, Emile R

    2017-12-01

    We employed near-infrared optical techniques, diffuse correlation spectroscopy (DCS), and frequency-domain near-infrared spectroscopy (FD-NIRS) to test the hypothesis that supervised exercise training increases skeletal muscle microvascular blood flow and oxygen extraction in patients with peripheral artery disease (PAD) who experience claudication. PAD patients ( n = 64) were randomly assigned to exercise and control groups. Patients in the exercise group received 3 mo of supervised exercise training. Calf muscle blood flow and oxygen extraction were optically monitored before, during, and after performance of a graded treadmill protocol at baseline and at 3 mo in both groups. Additionally, measurements of the ankle-brachial index (ABI) and peak walking time (PWT) to maximal claudication were made during each patient visit. Supervised exercise training was found to increase the maximal calf muscle blood flow and oxygen extraction levels during treadmill exercise by 29% (13%, 50%) and 8% (1%, 12%), respectively [ P group population were significantly higher than corresponding changes in the control group ( P training also increased PWT by 49% (18%, 101%) ( P = 0.01). However, within statistical error, the ABI, resting calf muscle blood flow and oxygen extraction, and the recovery half-time for hemoglobin\\myoglobin desaturation following cessation of maximal exercise were not altered by exercise training. The concurrent monitoring of both blood flow and oxygen extraction with the hybrid DCS/FD-NIRS instrument revealed enhanced muscle oxidative metabolism during physical activity from exercise training, which could be an underlying mechanism for the observed improvement in PWT. NEW & NOTEWORTHY We report on noninvasive optical measurements of skeletal muscle blood flow and oxygen extraction dynamics before/during/after treadmill exercise in peripheral artery disease patients who experience claudication. The measurements tracked the effects of a 3-mo supervised

  5. Reduced hypoxic ventilatory response with preserved blood oxygenation in yoga trainees and Himalayan Buddhist monks at altitude: evidence of a different adaptive strategy?

    Science.gov (United States)

    Bernardi, Luciano; Passino, Claudio; Spadacini, Giammario; Bonfichi, Maurizio; Arcaini, Luca; Malcovati, Luca; Bandinelli, Gabriele; Schneider, Annette; Keyl, Cornelius; Feil, Paul; Greene, Richard E; Bernasconi, Carlo

    2007-03-01

    Yoga induces long-term changes in respiratory function and control. We tested whether it represents a successful strategy for high-altitude adaptation. We compared ventilatory, cardiovascular and hematological parameters in: 12 Caucasian yoga trainees and 12 control sea-level residents, at baseline and after 2-week exposure to high altitude (Pyramid Laboratory, Nepal, 5,050 m), 38 active lifestyle high-altitude natives (Sherpas) and 13 contemplative lifestyle high-altitude natives with practice of yoga-like respiratory exercises (Buddhist monks) studied at 5,050 m. At baseline, hypoxic ventilatory response (HVR), red blood cell count and hematocrit were lower in Caucasian yoga trainees than in controls. After 14 days at altitude, yoga trainees showed similar oxygen saturation, blood pressure, RR interval compared to controls, but lower HVR (-0.44 +/- 0.08 vs. -0.98 +/- 0.21 l/min/m/%SaO(2), P monks was lower than in Sherpas (-0.23 +/- 0.05 vs. -0.63 +/- 0.09 l/min/m/%SaO(2), P monks as compared to Sherpas. In conclusion, Caucasian subjects practicing yoga maintain a satisfactory oxygen transport at high altitude, with minimal increase in ventilation and with reduced hematological changes, resembling Himalayan natives. Respiratory adaptations induced by the practice of yoga may represent an efficient strategy to cope with altitude-induced hypoxia.

  6. Time-Dependent Behavior of Microvascular Blood Flow and Oxygenation: A Predictor of Functional Outcomes.

    Science.gov (United States)

    Kuliga, Katarzyna Z; Gush, Rodney; Clough, Geraldine F; Chipperfield, Andrew John

    2018-05-01

    This study investigates the time-dependent behaviour and algorithmic complexity of low-frequency periodic oscillations in blood flux (BF) and oxygenation signals from the microvasculature. Microvascular BF and oxygenation (OXY: oxyHb, deoxyHb, totalHb, and SO 2 %) was recorded from 15 healthy young adult males using combined laser Doppler fluximetry and white light spectroscopy with local skin temperature clamped to 33  °C and during local thermal hyperaemia (LTH) at 43 °C. Power spectral density of the BF and OXY signals was evaluated within the frequency range (0.0095-1.6 Hz). Signal complexity was determined using the Lempel-Ziv (LZ) algorithm. Fold increase in BF during LTH was 15.6 (10.3, 22.8) and in OxyHb 4.8 (3.5, 5.9) (median, range). All BF and OXY signals exhibited multiple oscillatory components with clear differences in signal power distribution across frequency bands at 33 and 43 °C. Significant reduction in the intrinsic variability and complexity of the microvascular signals during LTH was found, with mean LZ complexity of BF and OxyHb falling by 25% and 49%, respectively ( ). These results provide corroboration that in human skin microvascular blood flow and oxygenation are influenced by multiple time-varying oscillators that adapt to local influences and become more predictable during increased haemodynamic flow. Recent evidence strongly suggests that the inability of microvascular networks to adapt to an imposed stressor is symptomatic of disease risk which might be assessed via BF and OXY via the combination signal analysis techniques described here.

  7. Blood transfusion improves renal oxygenation and renal function in sepsis-induced acute kidney injury in rats.

    Science.gov (United States)

    Zafrani, Lara; Ergin, Bulent; Kapucu, Aysegul; Ince, Can

    2016-12-20

    The effects of blood transfusion on renal microcirculation during sepsis are unknown. This study aimed to investigate the effect of blood transfusion on renal microvascular oxygenation and renal function during sepsis-induced acute kidney injury. Twenty-seven Wistar albino rats were randomized into four groups: a sham group (n = 6), a lipopolysaccharide (LPS) group (n = 7), a LPS group that received fluid resuscitation (n = 7), and a LPS group that received blood transfusion (n = 7). The mean arterial blood pressure, renal blood flow, and renal microvascular oxygenation within the kidney cortex were recorded. Acute kidney injury was assessed using the serum creatinine levels, metabolic cost, and histopathological lesions. Nitrosative stress (expression of endothelial (eNOS) and inducible nitric oxide synthase (iNOS)) within the kidney was assessed by immunohistochemistry. Hemoglobin levels, pH, serum lactate levels, and liver enzymes were measured. Fluid resuscitation and blood transfusion both significantly improved the mean arterial pressure and renal blood flow after LPS infusion. Renal microvascular oxygenation, serum creatinine levels, and tubular damage significantly improved in the LPS group that received blood transfusion compared to the group that received fluids. Moreover, the renal expression of eNOS was markedly suppressed under endotoxin challenge. Blood transfusion, but not fluid resuscitation, was able to restore the renal expression of eNOS. However, there were no significant differences in lactic acidosis or liver function between the two groups. Blood transfusion significantly improved renal function in endotoxemic rats. The specific beneficial effect of blood transfusion on the kidney could have been mediated in part by the improvements in renal microvascular oxygenation and sepsis-induced endothelial dysfunction via the restoration of eNOS expression within the kidney.

  8. 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

  9. Determination of blood oxygenation in the brain by time-resolved reflectance spectroscopy: influence of the skin, skull, and meninges

    Science.gov (United States)

    Hielscher, Andreas H.; Liu, Hanli; Wang, Lihong; Tittel, Frank K.; Chance, Britton; Jacques, Steven L.

    1994-07-01

    Near infrared light has been used for the determination of blood oxygenation in the brain but little attention has been paid to the fact that the states of blood oxygenation in arteries, veins, and capillaries differ substantially. In this study, Monte Carlo simulations for a heterogeneous system were conducted, and near infrared time-resolved reflectance measurements were performed on a heterogeneous tissue phantom model. The model was made of a solid polyester resin, which simulates the tissue background. A network of tubes was distributed uniformly through the resin to simulate the blood vessels. The time-resolved reflectance spectra were taken with different absorbing solutions filled in the network. Based on the simulation and experimental results, we investigated the dependence of the absorption coefficient obtained from the heterogeneous system on the absorption of the actual absorbing solution filled in the tubes. We show that light absorption by the brain should result from the combination of blood and blood-free tissue background.

  10. Blood pressure and calf muscle oxygen extraction during plantar flexion exercise in peripheral artery disease.

    Science.gov (United States)

    Luck, J Carter; Miller, Amanda J; Aziz, Faisal; Radtka, John F; Proctor, David N; Leuenberger, Urs A; Sinoway, Lawrence I; Muller, Matthew D

    2017-07-01

    Peripheral artery disease (PAD) is an atherosclerotic vascular disease that affects 200 million people worldwide. Although PAD primarily affects large arteries, it is also associated with microvascular dysfunction, an exaggerated blood pressure (BP) response to exercise, and high cardiovascular mortality. We hypothesized that fatiguing plantar flexion exercise that evokes claudication elicits a greater reduction in skeletal muscle oxygenation (SmO 2 ) and a higher rise in BP in PAD compared with age-matched healthy subjects, but low-intensity steady-state plantar flexion elicits similar responses between groups. In the first experiment, eight patients with PAD and eight healthy controls performed fatiguing plantar flexion exercise (from 0.5 to 7 kg for up to 14 min). In the second experiment, seven patients with PAD and seven healthy controls performed low-intensity plantar flexion exercise (2.0 kg for 14 min). BP, heart rate (HR), and SmO 2 were measured continuously using near-infrared spectroscopy (NIRS). SmO 2 is the ratio of oxygenated hemoglobin to total hemoglobin, expressed as a percent. At fatigue, patients with PAD had a greater increase in mean arterial BP (18 ± 2 vs. vs. 10 ± 2 mmHg, P = 0.029) and HR (14 ± 2 vs. 6 ± 2 beats/min, P = 0.033) and a greater reduction in SmO 2 (-54 ± 10 vs. -12 ± 4%, P = 0.001). However, both groups had similar physiological responses to low-intensity, nonpainful plantar flexion exercise. These data suggest that patients with PAD have altered oxygen uptake and/or utilization during fatiguing exercise coincident with an augmented BP response. NEW & NOTEWORTHY In this laboratory study, patients with peripheral artery disease performed plantar flexion exercise in the supine posture until symptoms of claudication occurred. Relative to age- and sex-matched healthy subjects we found that patients had a higher blood pressure response, a higher heart rate response, and a greater reduction in skeletal muscle oxygenation as

  11. 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).

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

    International Nuclear Information System (INIS)

    Takahashi, Ken

    1989-01-01

    Regional cerebral blood flow (rCBF), regional oxygen extraction fraction (rCEF) and regional cerebral metabolic rate for oxygen (rCMRO 2 ) were measured using the continuous inhalation technique for 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. 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 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 15 O gas, the 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 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 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 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 2 during NREM sleep suggested a decrease of the activity levels in the cerebral functions. (author)

  13. Regional oxygen saturation index (rSO2) in brachioradialis and deltoid muscle. Correlation and prognosis in patients with respiratory sepsis.

    Science.gov (United States)

    Rodríguez, A; Claverias, L; Marín, J; Magret, M; Rosich, S; Bodí, M; Trefler, S; Pascual, S; Gea, J

    2015-03-01

    To compare oxygen saturation index (rSO2) obtained simultaneously in two different brachial muscles. Prospective and observational study. Intensive care unit. Critically ill patients with community-acquired pneumonia. Two probes of NIRS device (INVOS 5100) were simultaneously placed on the brachioradialis (BR) and deltoid (D) muscles. rSO2 measurements were recorded at baseline (ICU admission) and at 24h. Demographic and clinical variables were registered. Pearson's correlation coefficient was used to assess the association between continuous variables. The consistency of the correlation was assessed using the intraclass correlation coefficient (ICC) and Bland-Altman plot. The predictive value of the rSO2 for mortality was calculated by ROC curve. Nineteen patients were included with an ICU mortality of 21.1%. The rSO2 values at baseline and at 24h were significantly higher in D than in BR muscle. Values obtained simultaneously in both limbs showed a strong correlation and adequate consistency: BR (r=0.95; p0.001) but a wide limit of agreement. Non-survivors had rSO2 values significantly lower than survivors at all times of the study. No patient with rSO2 >60% in BR died, and only 17.6% died with an rSO2 value >60% in D. Both muscles showed consistent discriminatory power for mortality. Both BR and D muscles were appropriate for measuring rSO2. Copyright © 2013 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

  14. Pulse Oximetry for the Detection of Obstructive Sleep Apnea Syndrome: Can the Memory Capacity of Oxygen Saturation Influence Their Diagnostic Accuracy?

    Directory of Open Access Journals (Sweden)

    Carlos A. Nigro

    2011-01-01

    Full Text Available Objective. To assess the diagnostic ability of WristOx 3100 using its three different recording settings in patients with suspected obstructive sleep apnea syndrome (OSAS. Methods. All participants (135 performed the oximetry (three oximeters WristOx 3100 and polysomnography (PSG simultaneously in the sleep laboratory. Both recordings were interpreted blindly. Each oximeter was set to one of three different recording settings (memory capabilities 0.25, 0.5, and 1 Hz. The software (nVision 5.1 calculated the adjusted O2 desaturation index-mean number of O2 desaturation per hour of analyzed recording ≥2, 3, and 4% (ADI2, 3, and 4. The ADI2, 3, and 4 cutoff points that better discriminated between subjects with or without OSAS arose from the receiver-operator characteristics (ROCs curve analysis. OSAS was defined as a respiratory disturbance index (RDI ≥ 5. Results. 101 patients were included (77 men, mean age 52, median RDI 22.6, median BMI 27.4 kg/m2. The area under the ROCs curves (AUC-ROCs of ADI2, 3, and 4 with different data storage rates were similar (AUC-ROCs with data storage rates of 0.25/0.5/1 Hz: ADI2: 0.958/0.948/0.965, ADI3: 0.961/0.95/0.966, and ADI4: 0.957/0.949/0.963, P NS. Conclusions. The ability of WristOx 3100 to detect patients with OSAS was not affected by the data storage rate of the oxygen saturation signal. Both memory capacity of 0.25, 0.5, or 1 Hz showed a similar performance for the diagnosis of OSAS.

  15. 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

    1991-01-01

    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 rather than...

  16. 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.

  17. Cerebral blood flow and oxygen consumption during ethanol withdrawal in the rat.

    Science.gov (United States)

    Hemmingsen, R; Barry, D I; Hertz, M M; Klinken, L

    1979-09-14

    The ethanol withdrawal syndrome in man and animals is characterized by signs of CNS hyperactivity although a direct measurement of a physiological variable reflecting this CNS hyperactivity has never been performed in untreated man or in animals. We induced ethanol dependence in the rat by means of intragastric intubation with a 20% w/v ethanol solution, thus keeping the animals in a state of continuous severe intoxication for 3--4 days; during the subsequent state of withdrawal characterized by tremor, rigidity, stereotyped movements and general seizures a 25% increase in cerebral oxygen consumption (CMRO2) could be measured; this increase was not due to catecholamines originating from adrenal medulla as adrenomedullectomized animals showed a similar increase in CMRO2 (28%); the withdrawing animals showed a corresponding cerebral blood flow (CBF) increase. The elevated CMRO2 and CBF could be reduced to normal by administration of a beta-adrenergic receptor blocker (propranolol 2 mg/kg i.v.), and hence the increased CMRO2 during ethanol withdrawal could be related to catecholaminergic systems in the brain, e.g. the noradrenergic locus coeruleus system which is anatomically well suited as a general activating system. This interpretation is supported by the earlier neurochemical finding of an increased cerebral noradrenaline turnover during ethanol withdrawal. The exact mechanism underlying the increased cerebral oxygen consumption during ethanol withdrawal and the effect of propranolol on cerebral function during this condition remains to be clarified.

  18. Reduction of blood oxygen levels enhances postprandial cardiac hypertrophy in Burmese python (Python bivittatus).

    Science.gov (United States)

    Slay, Christopher E; Enok, Sanne; Hicks, James W; Wang, Tobias

    2014-05-15

    Physiological cardiac hypertrophy is characterized by reversible enlargement of cardiomyocytes and changes in chamber architecture, which increase stroke volume and via augmented convective oxygen transport. Cardiac hypertrophy is known to occur in response to repeated elevations of O2 demand and/or reduced O2 supply in several species of vertebrate ectotherms, including postprandial Burmese pythons (Python bivittatus). Recent data suggest postprandial cardiac hypertrophy in P. bivittatus is a facultative rather than obligatory response to digestion, though the triggers of this response are unknown. Here, we hypothesized that an O2 supply-demand mismatch stimulates postprandial cardiac enlargement in Burmese pythons. To test this hypothesis, we rendered animals anemic prior to feeding, essentially halving blood oxygen content during the postprandial period. Fed anemic animals had heart rates 126% higher than those of fasted controls, which, coupled with a 71% increase in mean arterial pressure, suggests fed anemic animals were experiencing significantly elevated cardiac work. We found significant cardiac hypertrophy in fed anemic animals, which exhibited ventricles 39% larger than those of fasted controls and 28% larger than in fed controls. These findings support our hypothesis that those animals with a greater magnitude of O2 supply-demand mismatch exhibit the largest hearts. The 'low O2 signal' stimulating postprandial cardiac hypertrophy is likely mediated by elevated ventricular wall stress associated with postprandial hemodynamics. © 2014. Published by The Company of Biologists Ltd.

  19. 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 exacerbation of chronic obstructive pulmonary disease (COPD). Methods: Simultaneous arterial and peripheral venous blood was analysed. Venous values were used to calculate arterial pH, PCO2 and PO2, with these compared to measured values using Bland-Altman analysis and scatter plots. Calculated values of PO2......H, PCO2 and PO2 were 7.432±0.047, 6.8±1.7 kPa and 9.2±1.5 kPa, respectively. Calculated and measured arterial pH and PCO2 agreed well, differences having small bias and SD (0.000±0.022 pH, -0.06±0.50 kPa PCO2), significantly better than venous blood alone. Calculated PO2 obeyed the clinical rules...

  20. Numerical Investigation of Oxygenated and Deoxygenated Blood Flow through a Tapered Stenosed Arteries in Magnetic Field.

    Directory of Open Access Journals (Sweden)

    M Y Abdollahzadeh Jamalabadi

    Full Text Available Current paper is focused on transient modeling of blood flow through a tapered stenosed arteries surrounded a by solenoid under the presence of heat transfer. The oxygenated and deoxygenated blood are considered here by the Newtonian and Non-Newtonian fluid (power law and Carreau-Yasuda models. The governing equations of bio magnetic fluid flow for an incompressible, laminar, homogeneous, non-Newtonian are solved by finite volume method with SIMPLE algorithm for structured grid. Both magnetization and electric current source terms are well thought-out in momentum and energy equations. The effects of fluid viscosity model, Hartmann number, and magnetic number on wall shear stress, shearing stress at the stenosis throat and maximum temperature of the system are investigated and are optimized. The current study results are in agreement with some of the existing findings in the literature and are useful in thermal and mechanical design of spatially varying magnets to control the drug delivery and biomagnetic fluid flows through tapered arteries.

  1. 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. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Impact of partial pressure of oxygen in blood samples on the performance of systems for self-monitoring of blood glucose.

    Science.gov (United States)

    Schmid, Christina; Baumstark, Annette; Pleus, Stefan; Haug, Cornelia; Tesar, Martina; Freckmann, Guido

    2014-03-01

    The partial pressure of oxygen (pO2) in blood samples can affect glucose measurements with oxygen-sensitive systems. In this study, we assessed the influence of different pO2 levels on blood glucose (BG) measurements with five glucose oxidase (GOD) systems and one glucose dehydrogenase (GDH) system. All selected GOD systems were indicated by the manufacturers to be sensitive to increased oxygen content of the blood sample. Venous blood samples of 16 subjects (eight women, eight men; mean age, 52 years; three with type 1 diabetes, four with type 2 diabetes, and nine without diabetes) were collected. Aliquots of each sample were adjusted to the following pO2 values: ≤45 mm Hg, approximately 70 mm Hg, and ≥150 mm Hg. For each system, five consecutive measurements on each sample were performed using the same test strip lot. Relative differences between the mean BG value at a pO2 level of approximately 70 mm Hg, which was considered to be similar to pO2 values in capillary blood samples, and the mean BG value at pO2 levels ≤45 mm Hg and ≥150 mm Hg were calculated. The GOD systems showed mean relative differences between 11.8% and 44.5% at pO2 values ≤45 mm Hg and between -14.6% and -21.2% at pO2 values ≥150 mm Hg. For the GDH system, the mean relative differences were -0.3% and -0.2% at pO2 values ≤45 mm Hg and ≥150 mm Hg, respectively. The magnitude of the pO2 impact on BG measurements seems to vary among the tested oxygen-sensitive GOD systems. The pO2 range in which oxygen-sensitive systems operate well should be provided in the product information.

  3. Prefrontal blood flow and oxygenation measured by NIRS during long-term memory tasks are impaired by acute hyperglycemia (Conference Presentation)

    Science.gov (United States)

    Harris, R. Luke; Bell, Lindsay; Reimer, Andrea; Pettersen, Jacqueline A.; Siakaluk, Paul; Duffels, Brian

    2017-02-01

    Our goal was to use 2-channel frequency domain near-infrared spectroscopy (NIRS) to investigate the hemodynamic and metabolic mechanisms underlying hyperglycemia-associated long-term memory impairment. We hypothesized that prefrontal cortex (PFC) oxygen saturation (%Sat) and perfusion (tHb, i.e. total hemoglobin) would decrease due to hyperglycemia during learning, and then increase during recall. During learning, participants' blood glucose was manipulated with beverages containing either 47.4 mg saccharine control (CON, n = 10), or 50 g dextrose + 23.7 mg saccharine (GLC, n = 10). In the Symbol-Digit Modalities Test (SMDT) participants matched nine symbols to corresponding digits (1-9 inclusive), completing 105 learning and 15 testing trials on day 1 and 15 testing trials on day 2. From learning to recall, CON SMDT performance was unchanged, but GLC SMDT performance was decreased 11% (P = 0.0173). There were significant interactions (2-way ANOVA) between the CON-GLC treatment effects and the learning-recall effects for both PFC perfusion and oxygen saturation. Specifically, comparing learning to recall, CON exhibited no tHb differences but for GLC there was a large tHb decrease during learning with a partial recovery toward CON values during recall (P = 0.0012); and, comparing learning to recall, CON exhibited a large %Sat decrease but GLC exhibited a large %Sat increase (P = 0.021). We speculate that, during learning, after overnight fasting (CON) the PFC demands more hemodynamic and metabolic resources and "works" harder, but with readily available sugar (GLC) the PFC exhibits decreased "effort."

  4. Extraction of water labeled with oxygen 15 during single-capillary transit. Influence of blood pressure, osmolarity, and blood-brain barrier damage

    International Nuclear Information System (INIS)

    Go, K.G.; Lammertsma, A.A.; Paans, A.M.; Vaalburg, W.; Woldring, M.G.

    1981-01-01

    By external detection, the influence of arterial blood pressure (BP), osmolarity, and cold-induced blood-brain barrier damage was assessed on the extraction of water labeled with oxygen 15 during single-capillary transit in the rat. There was an inverse relation between arterial BP and extraction that was attributable to the influence of arterial BP on cerebral blood flow (CBF) and the relation between CBF and extraction. Neither arterial BP nor osmolarity of the injected bolus had any direct effect on extraction of water 15O, signifying that the diffusional exchange component (determined by blood flow) of extraction greatly surpasses the convection flow contribution by hydrostatic or osmotic forces. Damage to the blood-brain barrier did not change its permeability to water

  5. Removal of cellular-type hemoglobin-based oxygen carrier (hemoglobin-vesicles) from blood using centrifugation and ultrafiltration.

    Science.gov (United States)

    Sakai, Hiromi; Sou, Keitaro; Horinouchi, Hirohisa; Tsuchida, Eishun; Kobayashi, Koichi

    2012-02-01

    The hemoglobin-vesicle (HbV) is an artificial oxygen carrier encapsulating a concentrated hemoglobin solution in a phospholipid vesicle (liposome). During or after transporting oxygen, macrophages capture HbVs in the reticuloendothelial system (RES) with an approximate circulation half-life of 3 days. Animal studies show transient splenohepatomegaly after large doses, but HbVs were completely degraded, and the components were excreted in a few weeks. If a blood substitute is used for emergency use until red blood cell transfusion becomes available or for temporary use such as a priming fluid for an extracorporeal circuit, then one option would be to remove HbVs from the circulating blood without waiting a few weeks for removal by the RES. Using a mixture of beagle dog whole blood and HbV, we tested the separation of HbV using a centrifugal Fresenius cell separator and an ultrafiltration system. The cell separator system separated the layers of blood cell components from the HbV-containing plasma layer by centrifugal force, and then the HbV was removed from plasma phase by the ultrafiltration system. The HbVs (250-280 nm) are larger than plasma proteins (blood cell components (> 3 µm). The size of HbVs is advantageous to be separated from the original blood components, and the separated blood components can be returned to circulation. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  6. The association between lactate, mean arterial pressure, central venous oxygen saturation and peripheral temperature and mortality in severe sepsis: a retrospective cohort analysis.

    Science.gov (United States)

    Houwink, Aletta P I; Rijkenberg, Saskia; Bosman, Rob J; van der Voort, Peter H J

    2016-03-12

    During resuscitation in severe sepsis and septic shock, several goals are set. However, usually not all goals are equally met. The aim of this study is to determine the relative importance of the different goals, such as mean arterial pressure (MAP), lactate, central venous oxygen saturation (ScvO2) and central to forefoot temperature (delta-T), and how they relate to intensive care unit (ICU) and hospital mortality. In a retrospective cohort study in a 20-bed mixed medical and surgical ICU of a teaching hospital we studied consecutive critically ill patients who were admitted for confirmed infection and severe sepsis or septic shock between 2008 and 2014. All validated MAP, lactate levels, ScvO2 and delta-T for the first 24 hours of ICU treatment were extracted from a clinical database. Logistic regression analyses were performed on validated measurements in the first hour after admission and on mean values over 24 hours. Patients were categorized by MAP (24-hour mean below or above 65 mmHg) and lactate (24-hour mean below or above 2 mmol/l) for Cox regression analysis. From 837 patients, 821 were eligible for analysis. All had MAP and lactate measurements. The delta-T was available in 812 (99%) and ScvO2 was available for 193 out of these patients (23.5%). Admission lactate (p < 0.001) and admission MAP (p < 0.001) were independent predictors of ICU and hospital mortality. The 24-hour mean values for lactate, MAP and delta-T were all independent predictors of ICU mortality. Hospital mortality was independently predicted by the 24-hour mean lactate (odds ratio (OR) 1.34, 95% confidence interval (CI) 1.30-1.40, p = 0.001) mean MAP (OR 0.96, 95% CI 0.95-0.97, p = 0.001) and mean delta-T (OR 1.09, 95% CI 1.06-1.12, p = 0.001). Patients with a 24-hour mean lactate below 2 mmol/l and a 24-hour mean MAP above 65 mmHg had the best survival, followed by patients with a low lactate and a low MAP. Admission MAP and lactate independently predicted ICU and hospital mortality

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

    Science.gov (United States)

    Laufer, Jan; Delpy, Dave; Elwell, Clare; Beard, Paul

    2007-01-01

    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

  8. 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

  9. 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)

    Laufer, Jan; Delpy, Dave; Elwell, Clare; Beard, Paul

    2007-01-01

    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 2 ) and deoxyhaemoglobin (HHb) for the measurement of physiological parameters such as blood oxygen saturation (SO 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 2 and HHb, total haemoglobin concentration and SO 2 . The performance was found to compare favourably to that of a laboratory CO-oximeter with measurement resolutions of ±3.8 g l -1 (±58

  10. Effects of zilpaterol hydrochloride on methane production, total body oxygen consumption, and blood metabolites in finishing beef steers

    Science.gov (United States)

    An indirect calorimetry experiment was conducted to determine the effects of feeding zilpaterol hydrochloride (ZH) for 20 d on total body oxygen consumption, respiratory quotient, methane production, and blood metabolites in finishing beef steers. Sixteen Angus steers (initial BW = 555 ± 12.7 kg) w...

  11. Rejuvenation of stored human red blood cells reverses the renal microvascular oxygenation deficit in an isovolemic transfusion model in rats

    NARCIS (Netherlands)

    Raat, Nicolaas J. H.; Hilarius, Petra M.; Johannes, Tanja; de Korte, Dirk; Ince, Can; Verhoeven, Arthur J.

    2009-01-01

    BACKGROUND: Storage of red blood cells (RBCs) results in various biochemical changes, including a decrease in cellular adenosine triphosphate and 2,3-diphosphoglycerate acid. Previously it was shown that stored human RBCs show a deficit in the oxygenation of the microcirculation in the gut of

  12. Relation of Mitochondrial Oxygen Consumption in Peripheral Blood Mononuclear Cells to Vascular Function in Type 2 Diabetes Mellitus

    Science.gov (United States)

    Hartman, Mor-Li; Shirihai, Orian S.; Holbrook, Monika; Xu, Guoquan; Kocherla, Marsha; Shah, Akash; Fetterman, Jessica L.; Kluge, Matthew A.; Frame, Alissa A.; Hamburg, Naomi M.; Vita, Joseph A.

    2014-01-01

    Recent studies have shown mitochondrial dysfunction and increased production of reactive oxygen species in peripheral blood mononuclear cells (PBMC’s) and endothelial cells from patients with diabetes mellitus. Mitochondria oxygen consumption is coupled to ATP production and also occurs in an uncoupled fashion during formation of reactive oxygen species by components of the electron transport chain and other enzymatic sites. We therefore hypothesized that diabetes would be associated with higher total and uncoupled oxygen consumption in PBMC’s that would correlate with endothelial dysfunction. We developed a method to measure oxygen consumption in freshly isolated PBMC’s and applied it to 26 patients with type 2 diabetes mellitus and 28 non-diabetic controls. Basal (192±47 vs. 161±44 pMoles/min, P=0.01), uncoupled (64±16 vs. 53±16 pMoles/min, P=0.007), and maximal (795±87 vs. 715±128 pMoles/min, P=0.01) oxygen consumption rates were higher in diabetic patients compared to controls. There were no significant correlations between oxygen consumption rates and endothelium-dependent flow-mediated dilation measured by vascular ultrasound. Non-endothelium-dependent nitroglycerin-mediated dilation was lower in diabetics (10.1±6.6 vs. 15.8±4.8%, P=0.03) and correlated with maximal oxygen consumption (R= −0.64, P=0.001). In summary, we found that diabetes mellitus is associated with a pattern of mitochondrial oxygen consumption consistent with higher production of reactive oxygen species. The correlation between oxygen consumption and nitroglycerin-mediated dilation may suggest a link between mitochondrial dysfunction and vascular smooth muscle cell dysfunction that merits further study. Finally, the described method may have utility for assessment of mitochondrial function in larger scale observational and interventional studies in humans. PMID:24558030

  13. Detection of Acute Tubular Necrosis Using Blood Oxygenation Level-Dependent (BOLD MRI

    Directory of Open Access Journals (Sweden)

    Frederic Bauer

    2017-12-01

    Full Text Available Background/Aims: To date, there is no imaging technique to assess tubular function in vivo. Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI measures tissue oxygenation based on the transverse relaxation rate (R2*. The present study investigates whether BOLD MRI can assess tubular function using a tubule-specific pharmacological maneuver. Methods: Cross sectional study with 28 participants including 9 subjects with ATN-induced acute kidney injury (AKI, 9 healthy controls, and 10 subjects with nephron sparing tumor resection (NSS with clamping of the renal artery serving as a model of ischemia/reperfusion (I/R-induced subclinical ATN (median clamping time 15 min, no significant decrease of eGFR, p=0.14. BOLD MRI was performed before and 5, 7, and 10 min after intravenous administration of 40 mg furosemide. Results: Urinary neutrophil gelatinase-associated lipocalin was significantly higher in ATN-induced AKI and NSS subjects than in healthy controls (p=0.03 and p=0.01, respectively. Before administration of furosemide, absolute medullary R2*, cortical R2*, and medullary/cortical R2* ratio did not significantly differ between ATN-induced AKI vs. healthy controls and between NSS-I/R vs. contralateral healthy kidneys (p>0.05 each. Furosemide led to a significant decrease in the medullary and cortical R2* of healthy subjects and NSS contralateral kidneys (p<0.05 each, whereas there was no significant change of R2* in ATN-induced AKI and the NSS-I/R kidneys (p>0.05 each. Conclusion: BOLD-MRI is able to detect even mild tubular injury but necessitates a tubule-specific pharmacological maneuver, e.g. blocking the Na+-K+-2Cl- transporter by furosemide.

  14. Simultaneous imaging of cerebral partial pressure of oxygen and blood flow during functional activation and cortical spreading depression

    Science.gov (United States)

    Sakadžić, Sava; Yuan, Shuai; Dilekoz, Ergin; Ruvinskaya, Svetlana; Vinogradov, Sergei A.; Ayata, Cenk; Boas, David A.

    2009-01-01

    We developed a novel imaging technique that provides real-time two-dimensional maps of the absolute partial pressure of oxygen and relative cerebral blood flow in rats by combining phosphorescence lifetime imaging with laser speckle contrast imaging. Direct measurement of blood oxygenation based on phosphorescence lifetime is not significantly affected by changes in the optical parameters of the tissue during the experiment. The potential of the system as a novel tool for quantitative analysis of the dynamic delivery of oxygen to support brain metabolism was demonstrated in rats by imaging cortical responses to forepaw stimulation and the propagation of cortical spreading depression waves. This new instrument will enable further study of neurovascular coupling in normal and diseased brain. PMID:19340106

  15. Influence of Partial Pressure of Oxygen in Blood Samples on Measurement Performance in Glucose-Oxidase-Based Systems for Self-Monitoring of Blood Glucose

    Science.gov (United States)

    Baumstark, Annette; Schmid, Christina; Pleus, Stefan; Haug, Cornelia; Freckmann, Guido

    2013-01-01

    Background Partial pressure of oxygen (pO2) in blood samples can affect blood glucose (BG) measurements, particularly in systems that employ the glucose oxidase (GOx) enzyme reaction on test strips. In this study, we assessed the impact of different pO2 values on the performance of five GOx systems and one glucose dehydrogenase (GDH) system. Two of the GOx systems are labeled by the manufacturers to be sensitive to increased blood oxygen content, while the other three GOx systems are not. Methods Aliquots of 20 venous samples were adjusted to the following pO2 values: pO2 ~70 mmHg, which is considered to be similar to pO2 in capillary blood samples, and the mean BG result at pO2 pO2 pO2 ≥150 mmHg. For both pO2 levels, relative differences of all tested GOx systems were significant (p pO2 values pO2 variations lead to clinically relevant BG measurement deviations in GOx systems, even in GOx systems that are not labeled as being oxygen sensitive. PMID:24351177

  16. Myocardial Blood Volume Is Associated with Myocardial Oxygen Consumption: An Experimental Study with CMR in a Canine Model

    Science.gov (United States)

    McCommis, Kyle S.; Zhang, Haosen; Goldstein, Thomas A.; Misselwitz, Bernd; Abendschein, Dana R.; Gropler, Robert J.; Zheng, Jie

    2009-01-01

    OBJECTIVES To evaluate the feasibility of cardiovascular MR (CMR) to determine regional myocardial perfusion and O2 metabolism, and assess the role of myocardial blood volume (MBV) on oxygen supply. BACKGROUND Coronary artery disease presents as an imbalance of myocardial oxygen supply and demand. We have developed relevant CMR methods to determine the relationship of myocardial blood flow (MBF) and MBV to oxygen consumption (MVO2) during pharmacologic hyperemia. METHODS Twenty-one mongrel dogs were studied with varying stenosis severities imposed on the proximal left anterior descending (LAD) coronary artery. MBF and MBV were determined by CMR first-pass perfusion, while the oxygen extraction fraction (OEF) and MVO2 were determined by the myocardial Blood-Oxygen-Level-Dependent (BOLD) effect and Fick’s law, respectively. MR imaging was performed at rest, and during either dipyridamole-induced vasodilation or dobutamine-induced hyperemia. Regional differences in myocardial perfusion and oxygenation were then evaluated. RESULTS Dipyridamole and dobutamine both led to 145–200% increases in MBF and 50–80% increases in MBV in normal perfused myocardium. As expected, MVO2 increased more significantly with dobutamine (~175%) than dipyridamole (~40%). Coronary stenosis resulted in an attenuation of MBF, MBV, and MVO2 in both the LAD-subtended stenosis region and the left circumflex subtended remote region. Liner regression analysis showed that MBV reserve appears to be more correlated with MVO2 reserve during dobutamine stress than MBF reserve, particularly in the stenotic regions. Conversely, MBF reserve appears to be more correlated with MVO2 reserve during dipyridamole, although neither of these differences was significant. CONCLUSIONS Noninvasive evaluation of both myocardial perfusion and oxygenation by CMR facilitates direct monitoring of regional myocardial ischemia and provides a valuable tool for better understanding microvascular pathophysiology. These

  17. Regional blood flow distribution and oxygen metabolism during mesenteric ischemia and congestion.

    Science.gov (United States)

    Cruz, Ruy J; Garrido, Alejandra G; Ribeiro, Cristiane M F; Harada, Tomoyuki; Rocha-e-Silva, Mauricio

    2010-06-01

    Acute mesenteric ischemia is a potentially fatal vascular emergency with mortality rates ranging between 60% and 80%. Several studies have extensively examined the hemodynamic and metabolic effects of superior mesenteric artery occlusion. On the other hand, the cardiocirculatory derangement and the tissue damage induced by intestinal outflow obstruction have not been investigated systematically. For these reasons we decided to assess the initial impact of venous mesenteric occlusion on intestinal blood flow distribution, and correlate these findings with other systemic and regional perfusion markers. Fourteen mongrel dogs were subjected to 45 min of superior mesenteric artery (SMAO) or vein occlusion (SMVO), and observed for 120 min after reperfusion. Systemic hemodynamics were evaluated using Swan-Ganz and arterial catheters. Regional blood flow (ultrasonic flow probes), intestinal O(2)-derived variables, and mesenteric-arterial and tonometric-arterial pCO(2) gradients (D(mv-a)pCO(2) and D(t-a)pCO(2)) were also calculated. SMVO was associated with hypotension and low cardiac output. A significant increase in the regional pCO(2) gradients was also observed in both groups during the ischemic period. After reperfusion, a progressive reduction in D(mv-a)pCO(2) occurred in the SMVO group; however, no improvement in D(t-a)pCO(2) was observed. The histopathologic injury scores were 2.7 +/- 0.5 and 4.8 +/- 0.2 for SMAO and SMVO, respectively. SMV occlusion promoted early and significant hemodynamic and metabolic derangement at systemic and regional levels. Additionally, systemic pCO(2) gradient is not a reliable parameter to evaluate the local intestinal oxygenation. Finally, the D(t-a)pCO(2) correlates with histologic changes during intestinal congestion or ischemia. However, minor histologic changes cannot be detected using this methodology. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  18. 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 the microcirculation blood flow is highly regulated dependent on the metabolic activity of the tissues. Among several mechanisms, mechanisms involved in the coupling of changes in tissue oxygen tension due to changes in the metabolic activity of the tissue play an important role. In the systemic...... (inhibitor of KATP channels) in the superfusate abolished both vasodilatation and constriction to low and high oxygen superfusate, indicating that KATP channels are involved in both hypoxic vasodilatation and hyperoxic vasoconstriction. Red blood cells (RBCs) have been proposed to release ATP and...... as in the intact blood-perfused arteriole. This indicates that RBCs are not essential for hypoxic vasodilatation. In addition several potential pathways were evaluated. Application of DPCPX (inhibitor of adenosine A1 and A2 receptors) and L-NAME (inhibitor of NO-synthase) did not affect vasomotor responses to low...

  19. Prefrontal oxygenation correlates to the responses in facial skin blood flows during exposure to pleasantly charged movie.

    Science.gov (United States)

    Matsukawa, Kanji; Endo, Kana; Asahara, Ryota; Yoshikawa, Miho; Kusunoki, Shinya; Ishida, Tomoko

    2017-11-01

    Our laboratory reported that facial skin blood flow may serve as a sensitive tool to assess an emotional status. Cerebral neural correlates during emotional interventions should be sought in relation to the changes in facial skin blood flow. To test the hypothesis that prefrontal activity has positive relation to the changes in facial skin blood flow during emotionally charged stimulation, we examined the dynamic changes in prefrontal oxygenation (with near-infrared spectroscopy) and facial skin blood flows (with two-dimensional laser speckle and Doppler flowmetry) during emotionally charged audiovisual challenges for 2 min (by viewing comedy, landscape, and horror movie) in 14 subjects. Hand skin blood flow and systemic hemodynamics were simultaneously measured. The extents of pleasantness and consciousness for each emotional stimulus were estimated by subjective rating from -5 (the most unpleasant; the most unconscious) to +5 (the most pleasant; the most conscious). Positively charged emotional stimulation (comedy) simultaneously decreased ( P  horror) or neutral (landscape) emotional stimulation did not alter or slightly decreased them. Any of hand skin blood flow and systemic cardiovascular variables did not change significantly during positively charged emotional stimulation. The changes in prefrontal oxygenation had a highly positive correlation with the changes in facial skin blood flow without altering perfusion pressure, and they were inversely correlated with the subjective rating of pleasantness. The reduction in prefrontal oxygenation during positively charged emotional stimulation suggests a decrease in prefrontal neural activity, which may in turn elicit neurally mediated vasoconstriction of facial skin blood vessels. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  20. The Not-So-Global Blood Oxygen Level-Dependent Signal.

    Science.gov (United States)

    Billings, Jacob; Keilholz, Shella

    2018-04-01

    Global signal regression is a controversial processing step for resting-state functional magnetic resonance imaging, partly because the source of the global blood oxygen level-dependent (BOLD) signal remains unclear. On the one hand, nuisance factors such as motion can readily introduce coherent BOLD changes across the whole brain. On the other hand, the global signal has been linked to neural activity and vigilance levels, suggesting that it contains important neurophysiological information and should not be discarded. Any widespread pattern of coordinated activity is likely to contribute appreciably to the global signal. Such patterns may include large-scale quasiperiodic spatiotemporal patterns, known also to be tied to performance on vigilance tasks. This uncertainty surrounding the separability of the global BOLD signal from concurrent neurological processes motivated an examination of the global BOLD signal's spatial distribution. The results clarify that although the global signal collects information from all tissue classes, a diverse subset of the BOLD signal's independent components contribute the most to the global signal. Further, the timing of each network's contribution to the global signal is not consistent across volunteers, confirming the independence of a constituent process that comprises the global signal.

  1. Complexity of low-frequency blood oxygen level-dependent fluctuations covaries with local connectivity.

    Science.gov (United States)

    Anderson, Jeffrey S; Zielinski, Brandon A; Nielsen, Jared A; Ferguson, Michael A

    2014-04-01

    Very low-frequency blood oxygen level-dependent (BOLD) fluctuations have emerged as a valuable tool for describing brain anatomy, neuropathology, and development. Such fluctuations exhibit power law frequency dynamics, with largest amplitude at lowest frequencies. The biophysical mechanisms generating such fluctuations are poorly understood. Using publicly available data from 1,019 subjects of age 7-30, we show that BOLD fluctuations exhibit temporal complexity that is linearly related to local connectivity (regional homogeneity), consistently and significantly covarying across subjects and across gray matter regions. This relationship persisted independently of covariance with gray matter density or standard deviation of BOLD signal. During late neurodevelopment, BOLD fluctuations were unchanged with age in association cortex while becoming more random throughout the rest of the brain. These data suggest that local interconnectivity may play a key role in establishing the complexity of low-frequency BOLD fluctuations underlying functional magnetic resonance imaging connectivity. Stable low-frequency power dynamics may emerge through segmentation and integration of connectivity during development of distributed large-scale brain networks. Copyright © 2013 Wiley Periodicals, Inc.

  2. Reactive oxygen species inactivation improves pancreatic capillary blood flow in caerulein-induced pancreatitis in rats

    Directory of Open Access Journals (Sweden)

    Meirelles Jr. Roberto Ferreira

    2003-01-01

    Full Text Available PURPOSE: Reactive oxygen species (ROS inactivation was studied to determine alterations in the pancreatic capillary blood flow (PCBF during caerulein-induced pancreatitis in rats. METHODS: A laser-Doppler flowmeter to measure PCBF and N-t-Butyl-Phenylnitrone (PBN compound to inactivate ROS were used. Forty rats were divided in groups: 1 control; 2 caerulein; 3 PBN; 4 caerulein+PBN. Serum biochemistry and histopathological analyses were performed. RESULTS: PCBF measured a mean of 109.08 ± 14.54%, 68.24 ± 10.47%, 102.18 ± 10.23% and 87.73 ± 18.72% in groups 1, 2, 3 and 4, respectively. PCBF in groups 2 and 4 decreased 31.75 ± 16.79% and 12.26 ± 15.24%, respectively. Serum amylase was 1323.70 ± 239.10 U/l, 2184.60 ± 700.46 U/l, 1379.80 ± 265.72 U/l and 1622.10 ± 314.60 U/l in groups 1, 2, 3 and 4, respectively. There was a significant difference in the PCBF and serum amylase when compared groups 2 and 4. Cytoplasmatic vacuolation was present in groups 2 and 4. Otherwise, no qualitative changes were seen. CONCLUSION: ROS inactivation improves PCBF and minimizes the serum amylase increase during caerulein-induced pancreatitis. ROS effect may be one of the leading causative events in this model of acute pancreatitis.

  3. Cerebrovascular blood oxygenation level dependent pulsatility at baseline and following acute exercise among healthy adolescents.

    Science.gov (United States)

    Theyers, Athena E; Goldstein, Benjamin I; Metcalfe, Arron Ws; Robertson, Andrew D; MacIntosh, Bradley J

    2018-01-01

    Arterial stiffness is linked to cerebral small vessel damage and neurodegeneration, but barriers to accessing deep cerebrovascular anatomy limit our ability to assess the brain. This study describes an adaptation of a cardiac-related scrubbing method as a means of generating blood oxygenation level-dependent pulsatility maps based on the cardiac cycle. We examine BOLD pulsatility at rest, based on the non-parametric deviation from null metric, as well as changes following acute physiological stress from 20 min of moderate-intensity cycling in 45 healthy adolescents. We evaluate the influence of repetition time (TR) and echo time (TE) using simulated and multi-echo empirical data, respectively. There were tissue-specific and voxel-wise BOLD pulsatility decreases 20 min following exercise cessation. BOLD pulsatility detection was comparable over a range of TR and TE values when scan volumes were kept constant; however, short TRs (≤500 ms) and TEs (∼14 ms) acquisitions would yield the most efficient detection. Results suggest cardiac-related BOLD pulsatility may represent a robust and easily adopted method of mapping cerebrovascular pulsatility with voxel-wise resolution.

  4. New principle for measuring arterial blood oxygenation, enabling motion-robust remote monitoring.

    Science.gov (United States)

    van Gastel, Mark; Stuijk, Sander; de Haan, Gerard

    2016-12-07

    Finger-oximeters are ubiquitously used for patient monitoring in hospitals worldwide. Recently, remote measurement of arterial blood oxygenation (SpO 2 ) with a camera has been demonstrated. Both contact and remote measurements, however, require the subject to remain static for accurate SpO 2 values. This is due to the use of the common ratio-of-ratios measurement principle that measures the relative pulsatility at different wavelengths. Since the amplitudes are small, they are easily corrupted by motion-induced variations. We introduce a new principle that allows accurate remote measurements even during significant subject motion. We demonstrate the main advantage of the principle, i.e. that the optimal signature remains the same even when the SNR of the PPG signal drops significantly due to motion or limited measurement area. The evaluation uses recordings with breath-holding events, which induce hypoxemia in healthy moving subjects. The events lead to clinically relevant SpO 2 levels in the range 80-100%. The new principle is shown to greatly outperform current remote ratio-of-ratios based methods. The mean-absolute SpO 2 -error (MAE) is about 2 percentage-points during head movements, where the benchmark method shows a MAE of 24 percentage-points. Consequently, we claim ours to be the first method to reliably measure SpO 2 remotely during significant subject motion.

  5. Long term high flow humidified oxygen treatment in COPD – effect on blood gases

    DEFF Research Database (Denmark)

    Storgaard, Line; Weinreich, Ulla; Hockey, Hans

    2017-01-01

    .Aim: To investigate the treatment effect on arterial blood gases (PaO2, PaCO2 and SaO2) in patients with resting hypoxemia over 12 months.Method: In this prospective, randomized controlled, one-year study, 200 COPD patients treated with LTOT, all GOLD class 4, were randomized to NHF (n=100) or usual care (n=100......) between March 2013 and June 2015.Results: The groups are comparable in average days in study, age, gender, smoking status, pack years, BMI, FEV1%, 6 minutes walking test, administered oxygen (L/min), PaO2 PaCO2 and Sa02 at baseline and number of exacerbations and admissions one year prior to study start....... Treated with a mean NHF-flow of 20 L/min, no significant difference was seen in PaO2 or SaO2 over the study, but a significantly different change in PaCO2 was seen after 6 months (p<0.05) and after 12 months (p<0.01) in favor of patients treated with NHF. Increase in PaCO<2 was approximately 0...

  6. Blood oxygen-level dependent functional assessment of cerebrovascular reactivity: Feasibility for intraoperative 3 Tesla MRI.

    Science.gov (United States)

    Fierstra, Jorn; Burkhardt, Jan-Karl; van Niftrik, Christiaan Hendrik Bas; Piccirelli, Marco; Pangalu, Athina; Kocian, Roman; Neidert, Marian Christoph; Valavanis, Antonios; Regli, Luca; Bozinov, Oliver

    2017-02-01

    To assess the feasibility of functional blood oxygen-level dependent (BOLD) MRI to evaluate intraoperative cerebrovascular reactivity (CVR) at 3 Tesla field strength. Ten consecutive neurosurgical subjects scheduled for a clinical intraoperative MRI examination were enrolled in this study. In addition to the clinical protocol a BOLD sequence was implemented with three cycles of 44 s apnea to calculate CVR values on a voxel-by-voxel basis throughout the brain. The CVR range was then color-coded and superimposed on an anatomical volume to create high spatial resolution CVR maps. Ten subjects (mean age 34.8 ± 13.4; 2 females) uneventfully underwent the intraoperative BOLD protocol, with no complications occurring. Whole-brain CVR for all subjects was (mean ± SD) 0.69 ± 0.42, whereas CVR was markedly higher for tumor subjects as compared to vascular subjects, 0.81 ± 0.44 versus 0.33 ± 0.10, respectively. Furthermore, color-coded functional maps could be robustly interpreted for a whole-brain assessment of CVR. We demonstrate that intraoperative BOLD MRI is feasible in creating functional maps to assess cerebrovascular reactivity throughout the brain in subjects undergoing a neurosurgical procedure. Magn Reson Med 77:806-813, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  7. On the Effects of Reactive Oxygen Species and Nitric Oxide on Red Blood Cell Deformability

    Directory of Open Access Journals (Sweden)

    Lukas Diederich

    2018-05-01

    Full Text Available The main function of red blood cells (RBCs is the transport of respiratory gases along the vascular tree. To fulfill their task, RBCs are able to elastically deform in response to mechanical forces and, pass through the narrow vessels of the microcirculation. Decreased RBC deformability was observed in pathological conditions linked to increased oxidative stress or decreased nitric oxide (NO bioavailability, like hypertension. Treatments with oxidants and with NO were shown to affect RBC deformability ex vivo, but the mechanisms underpinning these effects are unknown. In this study we investigate whether changes in intracellular redox status/oxidative stress or nitrosation reactions induced by reactive oxygen species (ROS or NO may affect RBC deformability. In a case-control study comparing RBCs from healthy and hypertensive participants, we found that RBC deformability was decreased, and levels of ROS were increased in RBCs from hypertensive patients as compared to RBCs from aged-matched healthy controls, while NO levels in RBCs were not significantly different. To study the effects of oxidants on RBC redox state and deformability, RBCs from healthy volunteers were treated with increasing concentrations of tert-butylhydroperoxide (t-BuOOH. We found that high concentrations of t-BuOOH (≥ 1 mM significantly decreased the GSH/GSSG ratio in RBCs, decreased RBC deformability and increased blood bulk viscosity. Moreover, RBCs from Nrf2 knockout (KO mice, a strain genetically deficient in a number of antioxidant/reducing enzymes, were more susceptible to t-BuOOH-induced impairment in RBC deformability as compared to wild type (WT mice. To study the role of NO in RBC deformability we treated RBC suspensions from human volunteers with NO donors and nitrosothiols and analyzed deformability of RBCs from mice lacking the endothelial NO synthase (eNOS. We found that NO donors induced S-nitrosation of the cytoskeletal protein spectrin, but did not affect

  8. Myocardial blood flow and its transit time, oxygen utilization, and efficiency of highly endurance-trained human heart.

    Science.gov (United States)

    Heinonen, Ilkka; Kudomi, Nobuyuki; Kemppainen, Jukka; Kiviniemi, Antti; Noponen, Tommi; Luotolahti, Matti; Luoto, Pauliina; Oikonen, Vesa; Sipilä, Hannu T; Kopra, Jaakko; Mononen, Ilkka; Duncker, Dirk J; Knuuti, Juhani; Kalliokoski, Kari K

    2014-07-01

    Highly endurance-trained athlete's heart represents the most extreme form of cardiac adaptation to physical stress, but its circulatory alterations remain obscure. In the present study, myocardial blood flow (MBF), blood mean transit time (MTT), oxygen extraction fraction (OEF) and consumption (MVO2), and efficiency of cardiac work were quantified in highly trained male endurance athletes and control subjects at rest and during supine cycling exercise using [(15)O]-labeled radiotracers and positron emission tomography. Heart rate and MBF were lower in athletes both at rest and during exercise. OEF increased in response to exercise in both groups, but was higher in athletes (70 ± 21 vs. 63 ± 11 % at rest and 86 ± 13 vs. 73 ± 10 % during exercise). MTT was longer and vascular resistance higher in athletes both at rest and during exercise, but arterial content of 2,3-diphosphoglycerate (oxygen affinity) was unchanged. MVO2 per gram of myocardium trended (p = 0.08) lower in athletes both at rest and during exercise, while myocardial efficiency of work and MVO2 per beat were not different between groups. Arterial levels of free fatty acids were ~twofold higher in athletes likely leading to higher myocardial fatty acid oxidation and hence oxygen cost, which may have blunted the bradycardia-induced decrease in MVO2. Finally, the observed group differences in MBF, OEF, MTT and vascular resistance remained significant also after they were controlled for differences in MVO2. In conclusion, in highly endurance-trained human heart, increased myocardial blood transition time enables higher oxygen extraction levels with a lower myocardial blood flow and higher vascular resistance. These physiological adaptations to exercise training occur independently of the level of oxygen consumption and together with training-induced bradycardia may serve as mechanisms to increase functional reserve of the human heart.

  9. Partial neuromuscular blockade in humans enhances muscle blood flow during exercise independently of muscle oxygen uptake and acetylcholine receptor blockade

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Krustrup, Peter; Iaia, F Marcello

    2009-01-01

    This study examined the role of acetylcholine for skeletal muscle blood flow during exercise by use of the competitive neuromuscular blocking agent cisatracurium in combination with the acetylcholine receptor blocker glycopyrrone. Nine healthy male subjects performed a 10-min bout of one-legged k......This study examined the role of acetylcholine for skeletal muscle blood flow during exercise by use of the competitive neuromuscular blocking agent cisatracurium in combination with the acetylcholine receptor blocker glycopyrrone. Nine healthy male subjects performed a 10-min bout of one...... conductance during exercise, events that are not associated with either acetylcholine or an increased oxygen demand. The results do not support an essential role for acetylcholine, released form the neuromuscular junction, in exercise hyperaemia or for the enhanced blood flow during neuromuscular blockade....... The enhanced exercise hyperemia during partial neuromuscular blockade may be related to a greater recruitment of fast-twitch muscle fibres. Key words: blood flow, neuromuscular blockade, exercise, skeletal muscle....

  10. Six-minute walking distance and decrease in oxygen saturation during the six-minute walk test in pediatric pulmonary arterial hypertension

    NARCIS (Netherlands)

    Douwes, Johannes M.; Hegeman, Anneke K.; van der Krieke-van der Horst, Merel; Roofthooft, Marcus T. R.; Hillege, Hans L.; Berger, Rolf M. F.

    2016-01-01

    Objective: To investigate the prognostic value of the 6-minute walking distance (6-MWD), transcutaneous saturation (tcSO2) and heart rate (HR) obtained during the 6-minute walk test (6-MWT) in pediatric pulmonary arterial hypertension (PAH). Methods: This was an observational study with forty-seven

  11. Absolute measurement of cerebral optical coefficients, hemoglobin concentration and oxygen saturation in old and young adults with near-infrared spectroscopy

    Science.gov (United States)

    We present near-infrared spectroscopy measurement of absolute cerebral hemoglobin concentration and saturation in a large sample of 36 healthy elderly (mean age, 85 ± 6 years) and 19 young adults (mean age, 28 ± 4 years). Non-invasive measurements were obtained on the forehead using a commercially a...

  12. Measurement of forearm oxygen consumption

    DEFF Research Database (Denmark)

    Astrup, A; Simonsen, L; Bülow, J

    1988-01-01

    The classical forearm technique widely used for studies of skeletal muscle metabolism requires arterial cannulation. To avoid arterial puncture it is becoming more common to arterialize blood from a contralateral hand vein by local heating. This modification and the classical method have produced...... 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...... contradictory results regarding the contribution of skeletal muscle to glucose-induced thermogenesis. The effect on forearm circulation and the metabolism of heating the contralateral hand was examined before and after an oral glucose load. The results suggest that contralateral heating increases subcutaneous...

  13. Functional neuroanatomy in depressed patients with sexual dysfunction: blood oxygenation level dependent functional MR imaging

    International Nuclear Information System (INIS)

    Yang, Jong Chul

    2004-01-01

    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

  14. 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.

  15. Oxygen therapy - infants

    Science.gov (United States)

    ... breathe increased amounts of oxygen to get normal levels of oxygen in their blood. Oxygen therapy provides babies with the extra oxygen. Information Oxygen is a gas that the cells in your body need to work properly. The ...

  16. Decreased muscle oxygenation and increased arterial blood flow in the non-exercising limb during leg exercise.

    Science.gov (United States)

    Shiroishi, Kiyoshi; Kime, Ryotaro; Osada, Takuya; Murase, Norio; Shimomura, Kousuke; Katsumura, Toshihito

    2010-01-01

    We evaluated arterial blood flow, muscle tissue oxygenation and muscle metabolism in the non-exercising limb during leg cycling exercise. Ten healthy male volunteers performed a graded leg cycling exercise at 0, 40, 80, 120 and 160 watts (W) for 5 min each. Tissue oxygenation index (TOI) of the non-exercising left forearm muscle was measured using a near-infrared spatially resolved spectroscopy (NIR(SRS)), and non-exercising forearm blood flow ((NONEX)FBF) in the brachial artery was also evaluated by a Doppler ultrasound system. We also determined O(2) consumption of the non-exercising forearm muscle (NONEXV(O)(2mus)) by the rate of decrease in O(2)Hb during arterial occlusion at each work rate. TOI was significantly decreased at 160 W (p exercising muscle may be reduced, even though (NONEX)FBF increases at high work rates during leg cycling exercise.

  17. Blood flow and tissue oxygen pressures of liver and pancreas in rats: effects of volatile anesthetics and of hemorrhage.

    Science.gov (United States)

    Vollmar, B; Conzen, P F; Kerner, T; Habazettl, H; Vierl, M; Waldner, H; Peter, K

    1992-09-01

    The object of this investigation was to compare the effects of volatile anesthetics and of hemorrhage at comparable arterial blood pressures on splanchnic blood flow (radioactive microspheres) and tissue oxygenation of the liver and pancreas (surface PO2 [PSO2] electrodes). In contrast to earlier studies, we did not use identical minimum alveolar anesthetic concentration multiples as a reference to compare volatile anesthetics; rather, we used the splanchnic perfusion pressure. Under general anesthesia (intravenous chloralose) and controlled ventilation, 12 Sprague-Dawley rats underwent laparotomy to allow access to abdominal organs. Mean arterial pressure was decreased from 84 +/- 3 mm Hg (mean +/- SEM) at control to 50 mm Hg by 1.0 +/- 0.1 vol% halothane, 2.2 +/- 0.2 vol% enflurane, and 2.3 +/- 0.1 vol% isoflurane in a randomized sequence. For hemorrhagic hypotension, blood was withdrawn gradually until a mean arterial pressure of 50 mm Hg was attained. Volatile anesthetics and hemorrhage reduced cardiac output, and hepatic arterial, portal venous, and total hepatic blood flows by comparable degrees. Mean hepatic PSO2 decreased significantly from 30.7 +/- 2.6 mm Hg at control to 17.4 +/- 2 and 17.5 +/- 2 mm Hg during enflurane and isoflurane (each P less than 0.05) anesthesia, respectively. The decrease to 11.5 +/- 2.5 mm Hg was more pronounced during halothane anesthesia. Hemorrhagic hypotension was associated with the lowest hepatic PSO2 (3.4 +/- 1.3 mm Hg) and the highest number of hypoxic (0-5 mm Hg 86%) and anoxic PSO2 values (0 mm Hg 46%). Pancreatic blood flow and oxygenation remained unchanged from control during halothane and enflurane administration, whereas isoflurane increased both variables. Hemorrhagic hypotension slightly reduced pancreatic flow (-8%) but significantly decreased PSO2 from 58 +/- 5 mm Hg at control to 36 +/- 3 mm Hg, with 7% of all measured values in the hypoxic range. Thus, volatile anesthetics preserved pancreatic but not hepatic

  18. 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.)

  19. 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)

    Baron, J.C.; Rougemont, D.; Lebrun-Grandie, P.; Comar, D.; Bousser, M.G.; Bories, J.; Castaigne, P.; Cabanis, E.

    1982-09-01

    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 (lCMRO 2 ) 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 (lO 2 E), 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 lO 2 E values, from extremely low to extremely high, whereas the collapse of the lCMRO 2 is constant. Consequently this last parameter alone would be a good prognostic index, an lCMRO 2 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

  20. Barley seed radiosensitivity following post-hydration in oxygen-, nitrogen- and nitrous oxide-saturated water, 1; Influence of caffeine and t-butyl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.P.; Kesavan, P.C. (Jawaharlal Nehru Univ., New Delhi (India). School of Life Sciences)

    1990-06-01

    Dry ({approx}3.5 and 4.0 per cent moisture content) barley seeds were exposed to 350 Gy of {sup 60}Co-{gamma}-rays in vacuo and post-hydrated at 4degC for 8 h in O{sub 2}-, N{sub 2}-, or N{sub 2}O-saturated water. The effect of caffeine and t-butyl alcohol (t-BuOH) dissolved in the post-hydration medium on the magnitude of damage developing under these three different gaseous circumstances was studied. The post-irradiation damage and its modification by caffeine and t-BuOH was assessed in terms of 8-day-old seedling injury, peroxidase activity and total peroxides in the 8-day-old seedlings. Post-irradiation O{sub 2}-saturated hydration caused maximal 8-day-old seedling injury, and increased peroxidase activity with concomitant reduction in total peroxides. Both caffeine and t-BuOH afforded significant radioprotection against post-irradiation O{sub 2}-dependent damage. Post-irradiation N{sub 2}O-saturated hydration was even more significantly radioprotective than the N{sub 2}-saturated post-hydration. Under these circumstances, t-BuOH exerted no effect whatsoever on the N{sub 2}- and N{sub 2}O-mediated post-irradiation damage. Caffeine, on the other hand, significantly potentiated these two components of damage. A brief consideration of the physicochemical events which possibly account for the observed effects is presented. (author).

  1. 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.)

  2. 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)

    Zheng, Gang; Lou, Yaxian; Pan, Zhiying; Liu, Ya; Wen, Jiqiu; Li, Xue; Zhang, Zhe; Lu, Hanzhang; Liu, Wei; Liu, Hui; Chen, Huijuan; Kong, Xiang; Luo, Song; Jiang, Xiaolu; Zhang, Zongjun; Zhang, Long Jiang; Lu, Guang Ming

    2016-01-01

    To noninvasively assess global cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO 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 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 -1 100 g -1 , P < 0.001), elevated OEF (47.2 ± 10.2 vs. 35.8 ± 5.4 %, P < 0.001), but unaffected CMRO 2 (199.5 ± 36.4 vs. 193.8 ± 28.6 μmol O 2 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 CMRO 2 . Altered neuropsychological test scores of ESRD patients were associated with OEF and CBF, but not with CMRO 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 2 . Despite this compensatory process, however, cognitive function was still impaired and its severity was correlated with their CBF and OEF abnormality. (orig.)

  3. Application of language blood oxygenation level dependent functional MRI in the navigating operation of neurosurgery

    International Nuclear Information System (INIS)

    Liu Shuyong; Li Min; Yao Chengjun; Geng Daoying

    2011-01-01

    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

  4. The influence of nanodiamond on the oxygenation states and micro rheological properties of human red blood cells in vitro.

    Science.gov (United States)

    Lin, Yu-Chung; Tsai, Lin-Wei; Perevedentseva, Elena; Chang, Hsin-Hou; Lin, Ching-Hui; Sun, Der-Shan; Lugovtsov, Andrei E; Priezzhev, Alexander; Mona, Jani; Cheng, Chia-Liang

    2012-10-01

    Nanodiamond has been proven to be biocompatible and proposed for various biomedical applications. Recently, nanometer-sized diamonds have been demonstrated as an effective Raman/fluorescence probe for bio-labeling, as well as, for drug delivery. Bio-labeling/drug delivery can be extended to the human blood system, provided one understands the interaction between nanodiamonds and the blood system. Here, the interaction of nanodiamonds (5 and 100 nm) with human red blood cells (RBC) in vitro is discussed. Measurements have been facilitated using Raman spectroscopy, laser scanning fluorescence spectroscopy, and laser diffractometry (ektacytometry). Data on cell viability and hemolytic analysis are also presented. Results indicate that the nanodiamonds in the studied condition do not cause hemolysis, and the cell viability is not affected. Importantly, the oxygenation/deoxygenation process was not found to be altered when nanodiamonds interacted with the RBC. However, the nanodiamond can affect some RBC properties such as deformability and aggregation in a concentration dependent manner. These results suggest that the nanodiamond can be used as an effective bio-labeling and drug delivery tool in ambient conditions, without complicating the blood's physiological conditions. However, controlling the blood properties including deformability of RBCs and rheological properties of blood is necessary during treatment.

  5. 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%.

  6. Influence of glutamate-evoked pain and sustained elevated muscle activity on blood oxygenation in the human masseter muscle.

    Science.gov (United States)

    Suzuki, Shunichi; Arima, Taro; Kitagawa, Yoshimasa; Svensson, Peter; Castrillon, Eduardo

    2017-12-01

    This study aimed to investigate the effect of glutamate-evoked masseter muscle pain on intramuscular oxygenation during rest and sustained elevated muscle activity (SEMA). Seventeen healthy individuals participated in two sessions in which they were injected with glutamate and saline in random order. Each session was divided into three, 10-min periods. During the first (period 1) and the last (period 3) 10-min periods, participants performed five intercalated 1-min bouts of masseter SEMA with 1-min periods of 'rest'. At onset of the second 10-min period, glutamate (0.5 ml, 1 M; Ajinomoto, Tokyo, Japan) or isotonic saline (0.5 ml; 0.9%) was injected into the masseter muscle and the participants kept the muscle relaxed in a resting position for 10 min (period 2). The hemodynamic characteristics of the masseter muscle were recorded simultaneously during the experiment by a laser blood-oxygenation monitor. The results demonstrated that glutamate injections caused significant levels of self-reported pain in the masseter muscle; however, this nociceptive input did not have robust effects on intramuscular oxygenation during rest or SEMA tasks. Interestingly, these findings suggest an uncoupling between acute nociceptive activity and hemodynamic parameters in both resting and low-level active jaw muscles. Further studies are needed to explore the pathophysiological significance of blood-flow changes for persistent jaw-muscle pain conditions. © 2017 Eur J Oral Sci.

  7. Seasonal changes in blood oxygen transport and acid-base status in the tegu lizard, Tupinambis merianae.

    Science.gov (United States)

    Andrade, Denis V; Brito, Simone P; Toledo, Luís Felipe; Abe, Augusto S

    2004-05-20

    Oxygen-binding properties, blood gases, and acid-base parameters were studied in tegu lizards, Tupinambis merianae, at different seasons and temperatures. Independent of temperature and pH, blood oxygen affinity was higher in dormant lizards than in those active during the summer. Haematocrit (Hct) and hemoglobin content ([Hb]) were greater in active lizards resulting in a higher oxygen-carrying capacity. Nucleoside triphosphate content ([NTP]) was reduced during dormancy, but the ratio between [NTP] and [Hb] remained unchanged. Dormancy was accompanied by an increase in plasma bicarbonate ([HCO-(3)]pl) and an elevation of arterial CO2 partial pressure (PaCO2) and CO2 content in the plasma (CplCO2). These changes in acid-base parameters persist over a broad range of body temperatures. In vivo, arterial O2 partial pressure (PaO2) and O2 content (CaO2) were not affected by season and tended to increase with temperature. Arterial pH (pHa) of dormant animals is reduced compared to active lizards at body temperatures below 15 degrees C, while no significant difference was noticed at higher temperatures. Copyright 2003 Elsevier B.V.

  8. 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

    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...

  9. Membrane culture and reduced oxygen tension enhances cartilage matrix formation from equine cord blood mesenchymal stromal cells in vitro.

    Science.gov (United States)

    Co, C; Vickaryous, M K; Koch, T G

    2014-03-01

    Ongoing research is aimed at increasing cartilage tissue yield and quality from multipotent mesenchymal stromal cells (MSC) for the purpose of treating cartilage damage in horses. Low oxygen culture has been shown to enhance chondrogenesis, and novel membrane culture has been proposed to increase tissue yield and homogeneity. The objective of this study was to evaluate and compare the effect of reduced oxygen and membrane culture during in vitro chondrogenesis of equine cord blood (CB) MSC. CB-MSC (n = 5 foals) were expanded at 21% oxygen prior to 3-week differentiation in membrane or pellet culture at 5% and 21% oxygen. Assessment included histological examination (H&E, toluidine Blue, immunohistochemistry (IHC) for collagen type I and II), protein quantification by hydroxyproline assay and dimethylmethylene assay, and mRNA analysis for collagen IA1, collagen IIA1, collagen XA1, HIF1α and Sox9. Among treatment groups, 5% membrane culture produced neocartilage most closely resembling hyaline cartilage. Membrane culture resulted in increased wet mass, homogenous matrix morphology and an increase in total collagen content, while 5% oxygen culture resulted in higher GAG and type II collagen content. No significant differences were observed for mRNA analysis. Membrane culture at 5% oxygen produces a comparatively larger amount of higher quality neocartilage. Matrix homogeneity is attributed to a uniform diffusion gradient and reduced surface tension. Membrane culture holds promise for scale-up for therapeutic purposes, for cellular preconditioning prior to cytotherapeutic applications, and for modeling system for gas-dependent chondrogenic differentiation studies. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  10. Cerebral Metabolic Rate of Oxygen (CMRO2 ) Mapping by Combining Quantitative Susceptibility Mapping (QSM) and Quantitative Blood Oxygenation Level-Dependent Imaging (qBOLD).

    Science.gov (United States)

    Cho, Junghun; Kee, Youngwook; Spincemaille, Pascal; Nguyen, Thanh D; Zhang, Jingwei; Gupta, Ajay; Zhang, Shun; Wang, Yi

    2018-03-07

    To map the cerebral metabolic rate of oxygen (CMRO 2 ) by estimating the oxygen extraction fraction (OEF) from gradient echo imaging (GRE) using phase and magnitude of the GRE data. 3D multi-echo gradient echo imaging and perfusion imaging with arterial spin labeling were performed in 11 healthy subjects. CMRO 2 and OEF maps were reconstructed by joint quantitative susceptibility mapping (QSM) to process GRE phases and quantitative blood oxygen level-dependent (qBOLD) modeling to process GRE magnitudes. Comparisons with QSM and qBOLD alone were performed using ROI analysis, paired t-tests, and Bland-Altman plot. The average CMRO 2 value in cortical gray matter across subjects were 140.4 ± 14.9, 134.1 ± 12.5, and 184.6 ± 17.9 μmol/100 g/min, with corresponding OEFs of 30.9 ± 3.4%, 30.0 ± 1.8%, and 40.9 ± 2.4% for methods based on QSM, qBOLD, and QSM+qBOLD, respectively. QSM+qBOLD provided the highest CMRO 2 contrast between gray and white matter, more uniform OEF than QSM, and less noisy OEF than qBOLD. Quantitative CMRO 2 mapping that fits the entire complex GRE data is feasible by combining QSM analysis of phase and qBOLD analysis of magnitude. © 2018 International Society for Magnetic Resonance in Medicine.

  11. High impact of uranyl ions on carrying-releasing oxygen capability of hemoglobin-based blood substitutes

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Li; Du, Lili; Liu, Wenyuan; Liu, Zhichao [Northwest Institute of Nuclear Technology, Xi' an, Shaanxi (China); Jia, Yi; Li, Junbai [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Colloid Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing (China)

    2015-01-07

    The effect of radioactive UO{sub 2}{sup 2+} on the oxygen-transporting capability of hemoglobin-based oxygen carriers has been investigated in vitro. The hemoglobin (Hb) microspheres fabricated by the porous template covalent layer-by-layer (LbL) assembly were utilized as artificial oxygen carriers and blood substitutes. Magnetic nanoparticles of iron oxide (Fe{sub 3}O{sub 4}) were loaded in porous CaCO{sub 3} particles for magnetically assisted chemical separation (MACS). Through the adsorption spectrum of magnetic Hb microspheres after adsorbing UO{sub 2}{sup 2+}, it was found that UO{sub 2}{sup 2+} was highly loaded in the magnetic Hb microspheres, and it shows that the presence of UO{sub 2}{sup 2+} in vivo destroys the structure and oxygen-transporting capability of Hb microspheres. In view of the high adsorption capacity of UO{sub 2}{sup 2+}, the as-assembled magnetic Hb microspheres can be considered as a novel, highly effective adsorbent for removing metal toxins from radiation-contaminated bodies, or from nuclear-power reactor effluent before discharge into the environment. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. 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...

  13. Assessing the impacts of deoxygenation on marine species using blood-oxygen binding thresholds as proxies for hypoxia tolerance in the water column

    Science.gov (United States)

    Smith-Mislan, A.; Deutsch, C.; Dunne, J. P.; Sarmiento, J. L.

    2016-02-01

    Oxygen and temperature decrease, often rapidly, from shallow to deeper depths, restricting the ability of marine species to use the vertical habitat. One physiological trait that determines the tolerance of organisms to low oxygen is the oxygen affinity of respiratory pigments, hemoglobin and hemocyanin, in the blood. Oxygen affinity is sensitive to temperature because the reversible reaction between oxygen and blood pigments absorbs or releases energy, called the heat of oxygenation. To quantify the range of oxygen affinities for marine species, we surveyed the literature for measurements of oxygen binding to blood at multiple temperatures. Oxygen affinity is mapped within the ocean environment using the depth at which oxygen pressure decreases to the point at which the blood is 50% oxygenated (P50 depth) as organisms move from the surface to depth in the ocean water column. We calculate P50 depths for hydrographic observations and model simulations and find that vertical gradients in both temperature and oxygen impact the vertical position and areal extent of P50 depths. Shifts in P50 due to temperature cause physiological types with the same P50 in the surface ocean to have different P50 depths and physiological types with different P50's in the surface ocean to have the same P50 depth. The vertical distances between P50 depths are spatially variable, which may determine the frequency of ecological interactions, such as competition and predation. P50 depths provide new insights into the historical and future impacts of changing hypoxic zones on species living in pelagic habitats.

  14. 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

  15. Multiple taxon multiple locality approach to providing oxygen isotope evidence for warm-blooded theropod dinosaurs

    Science.gov (United States)

    Fricke, Henry C.; Rogers, Raymond R.

    2000-09-01

    Oxygen isotope ratios of fossil remains of coexisting taxa from several different localities can be used to help investigate dinosaur thermoregulation. Focusing on the Late Cretaceous, oxygen isotope ratios of crocodile tooth enamel from four separate localities exhibit less of a decrease with latitude than do ratios of tooth enamel from coexisting theropod dinosaurs. A shallower latitudinal gradient for crocodiles is consistent with how oxygen isotope ratios should vary for heterothermic animals having body temperatures coupled with their environments (“cold blooded”), while a steeper gradient for theropods is consistent with how these ratios should vary for homeothermic animals having constant body temperatures independent of their environments (“warm blooded”). This inferred homoethermy in theropods is likely due to higher rates of metabolic heat production relative to crocodiles and is not an artifact of body size.

  16. 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

  17. 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...... parameters of the whisker/infraorbital nerve etwork (IO) targeting the same cortical area. We tested the hypothesis that the relation between increases in CBF and CMRO2 evoked by stimulation and synaptic activity differed for the two activated networks and that activation of two distinct networks activate...

  18. 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

    ) 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......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...

  19. 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...... that the 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...

  20. 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.

  1. 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.

    Science.gov (United States)

    Zheng, Gang; Wen, Jiqiu; Lu, Hanzhang; Lou, Yaxian; Pan, Zhiying; Liu, Wei; Liu, Hui; Li, Xue; Zhang, Zhe; Chen, Huijuan; Kong, Xiang; Luo, Song; Jiang, Xiaolu; Liu, Ya; Zhang, Zongjun; Zhang, Long Jiang; Lu, Guang Ming

    2016-06-01

    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. • Anaemic young adults with ESRD may afford higher CBF and OEF. • Anaemic young adults with ESRD maintain a normal CMRO 2 . • Cognitive function was still impaired in young ESRD adults. • The severity of cognitive dysfunction correlated with CBF and OEF changes.

  2. Influence of residual oxygen-15-labeled carbon monoxide radioactivity on cerebral blood flow and oxygen extraction fraction in a dual-tracer autoradiographic method.

    Science.gov (United States)

    Iwanishi, Katsuhiro; Watabe, Hiroshi; Hayashi, Takuya; Miyake, Yoshinori; Minato, Kotaro; Iida, Hidehiro

    2009-06-01

    Cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO(2)), oxygen extraction fraction (OEF), and cerebral blood volume (CBV) are quantitatively measured with PET with (15)O 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 (15)O(2) and C(15)O(2) gases. In this protocol, before the sequential PET scan with (15)O(2) and C(15)O(2) gases ((15)O(2)-C(15)O(2) PET scan), a PET scan with C(15)O should be preceded to obtain CBV image. C(15)O has a high affinity for red blood cells and a very slow washout rate, and residual radioactivity from C(15)O might exist during a (15)O(2)-C(15)O(2) PET scan. As the current DARG method assumes no residual C(15)O radioactivity before scanning, we performed computer simulations to evaluate the influence of the residual C(15)O 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 C(15)O radioactivity. In the simulation, normal and ischemic conditions were considered. The (15)O(2) and C(15)O(2) PET count curves with the residual C(15)O PET counts were generated by the arterial input function with the residual C(15)O radioactivity. The amounts of residual C(15)O radioactivity were varied by changing the interval between the C(15)O PET scan and (15)O(2)-C(15)O(2) PET scan, and the absolute inhaled radioactivity of the C(15)O 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 C(15)O gas in the input function and PET counts. Our simulations revealed that the CBF and OEF values were underestimated by the residual C(15)O radioactivity. The magnitude of this underestimation depended on the amount of C(15)O radioactivity and the physiological conditions. This underestimation

  3. Exogenous and endogenous angiotensin-II decrease renal cortical oxygen tension in conscious rats by limiting renal blood flow.

    Science.gov (United States)

    Emans, Tonja W; Janssen, Ben J; Pinkham, Maximilian I; Ow, Connie P C; Evans, Roger G; Joles, Jaap A; Malpas, Simon C; Krediet, C T Paul; Koeners, Maarten P

    2016-11-01

    Our understanding of the mechanisms underlying the role of hypoxia in the initiation and progression of renal disease remains rudimentary. We have developed a method that allows wireless measurement of renal tissue oxygen tension in unrestrained rats. This method provides stable and continuous measurements of cortical tissue oxygen tension (PO2) for more than 2 weeks and can reproducibly detect acute changes in cortical oxygenation. Exogenous angiotensin-II reduced renal cortical tissue PO2 more than equi-pressor doses of phenylephrine, probably because it reduced renal oxygen delivery more than did phenylephrine. Activation of the endogenous renin-angiotensin system in transgenic Cyp1a1Ren2 rats reduced cortical tissue PO2; in this model renal hypoxia precedes the development of structural pathology and can be reversed acutely by an angiotensin-II receptor type 1 antagonist. Angiotensin-II promotes renal hypoxia, which may in turn contribute to its pathological effects during development of chronic kidney disease. We hypothesised that both exogenous and endogenous angiotensin-II (AngII) can decrease the partial pressure of oxygen (PO2) in the renal cortex of unrestrained rats, which might in turn contribute to the progression of chronic kidney disease. Rats were instrumented with telemeters equipped with a carbon paste electrode for continuous measurement of renal cortical tissue PO2. The method reproducibly detected acute changes in cortical oxygenation induced by systemic hyperoxia and hypoxia. In conscious rats, renal cortical PO2 was dose-dependently reduced by intravenous AngII. Reductions in PO2 were significantly greater than those induced by equi-pressor doses of phenylephrine. In anaesthetised rats, renal oxygen consumption was not affected, and filtration fraction was increased only in the AngII infused animals. Oxygen delivery decreased by 50% after infusion of AngII and renal blood flow (RBF) fell by 3.3 ml min -1 . Equi-pressor infusion of

  4. Exogenous and endogenous angiotensin‐II decrease renal cortical oxygen tension in conscious rats by limiting renal blood flow

    Science.gov (United States)

    Emans, Tonja W.; Janssen, Ben J.; Pinkham, Maximilian I.; Ow, Connie P. C.; Evans, Roger G.; Joles, Jaap A.; Malpas, Simon C.; Krediet, C. T. Paul

    2016-01-01

    Key points Our understanding of the mechanisms underlying the role of hypoxia in the initiation and progression of renal disease remains rudimentary.We have developed a method that allows wireless measurement of renal tissue oxygen tension in unrestrained rats.This method provides stable and continuous measurements of cortical tissue oxygen tension (PO2) for more than 2 weeks and can reproducibly detect acute changes in cortical oxygenation.Exogenous angiotensin‐II reduced renal cortical tissue PO2 more than equi‐pressor doses of phenylephrine, probably because it reduced renal oxygen delivery more than did phenylephrine.Activation of the endogenous renin–angiotensin system in transgenic Cyp1a1Ren2 rats reduced cortical tissue PO2; in this model renal hypoxia precedes the development of structural pathology and can be reversed acutely by an angiotensin‐II receptor type 1 antagonist.Angiotensin‐II promotes renal hypoxia, which may in turn contribute to its pathological effects during development of chronic kidney disease. Abstract We hypothesised that both exogenous and endogenous angiotensin‐II (AngII) can decrease the partial pressure of oxygen (PO2) in the renal cortex of unrestrained rats, which might in turn contribute to the progression of chronic kidney disease. Rats were instrumented with telemeters equipped with a carbon paste electrode for continuous measurement of renal cortical tissue PO2. The method reproducibly detected acute changes in cortical oxygenation induced by systemic hyperoxia and hypoxia. In conscious rats, renal cortical PO2 was dose‐dependently reduced by intravenous AngII. Reductions in PO2 were significantly greater than those induced by equi‐pressor doses of phenylephrine. In anaesthetised rats, renal oxygen consumption was not affected, and filtration fraction was increased only in the AngII infused animals. Oxygen delivery decreased by 50% after infusion of AngII and renal blood flow (RBF) fell by 3.3 ml min−1

  5. Combination of hyperbaric oxygenation, blood ultraviolet irradiation and hemisorption in treatment of patients with postoperational peritonitis

    International Nuclear Information System (INIS)

    Lisak, B.I.; Ivanov, M.A.

    1988-01-01

    Results of treatment of patients with postoperational peritonitis are taken as examples to carry out a comparative evaluation of modern methods of correction of changes of homeostasis and detoxication-hemisorption, ultraviolet irradiation of autoblood, hyperbaric oxygenation, as well as of traditional approach to removal of intra-abdominal sepsis in isolated version. 69 refs.; 3 tabs

  6. Image-Based Modeling of Blood Flow and Oxygen Transfer in Feto-Placental Capillaries

    Czech Academy of Sciences Publication Activity Database

    Pearce, P.; Brownbill, P.; Janáček, Jiří; Jirkovská, M.; Kubínová, Lucie; Chernyavsky, I. L.; Jensen, O. E.

    2016-01-01

    Roč. 11, č. 10 (2016), č. článku e0165369. E-ISSN 1932-6203 Institutional support: RVO:67985823 Keywords : placenta * capillaries * oxygen transfer * confocal microscopy Subject RIV: EA - Cell Biology Impact factor: 2.806, year: 2016

  7. Respiratory adaptations in carp blood. Influences of hypoxia, red cell organic phosphates, divalent cations and CO2 on hemoglobin-oxygen affinity

    DEFF Research Database (Denmark)

    Weber, Roy E.; Lykkeboe, G.

    1978-01-01

    This study concerns the adaptation of oxygen transporting function of carp blood to environment hypoxia, tracing the roles played by erythrocytic cofactors, inorganic cations, carbon dioxide and hemoglobin multiplicity. Carp acclimated to hypoxia ( 30 mmHg) display striking increases in blood oxy...

  8. Feed-derived volatile basic nitrogen increases reactive oxygen species production of blood leukocytes in lactating dairy cows.

    Science.gov (United States)

    Tsunoda, Ei; Gross, Josef J; Kawashima, Chiho; Bruckmaier, Rupert M; Kida, Katsuya; Miyamoto, Akio

    2017-01-01

    The present study investigated over 9 months the changes of fermentative quality of total mixed rations (TMR) containing grass silage (GS) as a major component, associated with changes in the volatile basic nitrogen (VBN) levels in an experimental dairy farm. Effects of VBN levels in TMR on metabolic parameters, reactive oxygen species (ROS) production by blood polymorphonuclear leukocytes (PMNs) and conception rates for dairy cows were analyzed. According to VBN levels in TMR during survey periods, three distinct phases were identified; phase A with low VBN; phase B with high VBN; and phase C with mid-VBN. Metabolic parameters in blood were all within normal range. However, during phases B and C, nitrogen metabolic indices such as blood urea nitrogen and milk urea nitrogen showed higher levels compared to those in phase A, and a simultaneous increase in ROS production by blood PMNs and the load on hepatic function in metabolic parameters was observed in the cows with a lower conception rate. This suggests that feeding TMR with elevated VBN levels due to poor fermented GS results in stimulation of ROS production by PMNs by ammonia, and negatively affects metabolism and reproductive performance in lactating dairy cow. © 2016 Japanese Society of Animal Science.

  9. Blood oxygen depletion is independent of dive function in a deep diving vertebrate, the northern elephant seal.

    Directory of Open Access Journals (Sweden)

    Jessica U Meir

    Full Text Available Although energetics is fundamental to animal ecology, traditional methods of determining metabolic rate are neither direct nor instantaneous. Recently, continuous blood oxygen (O2 measurements were used to assess energy expenditure in diving elephant seals (Mirounga angustirostris, demonstrating that an exceptional hypoxemic tolerance and exquisite management of blood O2 stores underlie the extraordinary diving capability of this consummate diver. As the detailed relationship of energy expenditure and dive behavior remains unknown, we integrated behavior, ecology, and physiology to characterize the costs of different types of dives of elephant seals. Elephant seal dive profiles were analyzed and O2 utilization was classified according to dive type (overall function of dive: transit, foraging, food processing/rest. This is the first account linking behavior at this level with in vivo blood O2 measurements in an animal freely diving at sea, allowing us to assess patterns of O2 utilization and energy expenditure between various behaviors and activities in an animal in the wild. In routine dives of elephant seals, the blood O2 store was significantly depleted to a similar range irrespective of dive function, suggesting that all dive types have equal costs in terms of blood O2 depletion. Here, we present the first physiological evidence that all dive types have similarly high blood O2 demands, supporting an energy balance strategy achieved by devoting one major task to a given dive, thereby separating dive functions into distinct dive types. This strategy may optimize O2 store utilization and recovery, consequently maximizing time underwater and allowing these animals to take full advantage of their underwater resources. This approach may be important to optimizing energy expenditure throughout a dive bout or at-sea foraging trip and is well suited to the lifestyle of an elephant seal, which spends > 90% of its time at sea submerged making diving its

  10. Relationship between level of forage intake, blood flow and oxygen consumption by splanchnic tissues of sheep fed a tropical grass forage.

    Science.gov (United States)

    Hentz, F; Kozloski, G V; Zeni, D; Brun, M V; Stefanello, S

    2017-02-01

    Four Polwarth castrated male sheep (42 ± 4.4 kg live weight (LW) surgically implanted with chronic indwelling catheters into the mesenteric, portal and hepatic veins, housed in metabolism cages and offered Cynodon sp. hay at rates (g of dry matter (DM)/kg LW) of 7, 14, 21 or ad libitum, were used in a 4 × 4 Latin square experiment to evaluate the effect of the level of forage intake on blood flow and oxygen consumption by the portal-drained viscera (PDV), liver and total splanchnic tissues (ST). The portal blood flow and the oxygen consumption by PDV linearly increased at increased organic matter (OM) intake. No effect of level of OM intake was obtained for the hepatic artery blood flow and oxygen consumption by liver. As a consequence, the level of OM intake only tended to directly affect hepatic blood flow and oxygen consumption by total ST. Oxygen consumption was linearly and positively related to blood flow across PDV, liver and total ST. The heat production by PDV and total ST, as proportion of metabolizable energy (ME) intake, decreased curvilinearly at increased ME intake. In conclusion, the oxygen consumption by PDV, but not by liver, was directly related to the level of forage intake by sheep. Moreover, when ingested at levels below maintenance, most of ME was spent as heat produced by ST. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

  11. Effect of oxygen fugacity on OH dissolution in olivine under peridotite-saturated conditions: An experimental study at 1.5-7 GPa and 1100-1300 °C

    Science.gov (United States)

    Yang, Xiaozhi

    2016-01-01

    The dissolution of OH in olivine by experimental studies at simulated conditions has attracted increasing interest over the past three decades, and the influence of pressure, temperature and composition has been relatively well constrained. Oxygen fugacity is highly heterogeneous in the upper mantle, on both temporal and spatial scales, and is an important parameter in characterizing many chemical and physical processes in the mantle. However, less attention has been devoted to the effect of oxygen fugacity on OH dissolution in olivine, and the only few available reports on this topic have led to significant inconsistency and debate. In this study, the correlation between oxygen fugacity and OH solubility in Fe-bearing olivine has been systematically investigated by conducting experiments at 1.5-7 GPa and 1100-1300 °C and under peridotite- and fluid-saturated conditions, with natural gem-quality olivine single crystals and fresh peridotite xenoliths as starting materials and with oxygen fugacity controlled by the Fe-FeO, Ni-NiO and Fe2O3-Fe3O4 oxygen buffer pairs. The water concentrations were determined by polarized analyses using a Fourier-transform infrared spectroscopy. The results show that, at all the experimental conditions, the OH bands at both high frequency (∼3650-3450 cm-1) and low frequency (∼3450-3100 cm-1) are prominent. The intensity of OH bands at ∼3355 and 3325 cm-1 increases positively with oxygen fugacity, suggesting a dominant role of Fe3+ in their incorporation. Under otherwise identical conditions, the water content is gradually enhanced with increasing pressure, temperature or oxygen fugacity. The effect of oxygen fugacity on the enhancement of OH solubility appears not sensitive to temperature (1100-1300 °C) at a given pressure, but becomes progressively stronger with increasing pressure from 1.5 to 7 GPa given the temperature. Relative to oxygen fugacity buffers, the OH solubility is on average increased by ∼50% between Fe-FeO and

  12. Data on the effect of target temperature management at 32–34 °C in cardiac arrest patients considering assessment by regional cerebral oxygen saturation: A multicenter retrospective cohort study

    Directory of Open Access Journals (Sweden)

    Yuka Nakatani

    2018-04-01

    Full Text Available This data article contains raw data and supplementary analyzed data regarding to the article entitled “Effect of target temperature management at 32–34 °C in cardiac arrest patients considering assessment by regional cerebral oxygen saturation: A multicenter retrospective cohort study”. We examined the effectiveness of target temperature management (TTM at 32–34 °C considering degrees of patients’ cerebral injury and cerebral circulation assessed by regional cerebral oxygen saturation (rSO2. The research is a secondary analysis of prospectively collected registry, in which comatose patients who were transferred to 15 hospitals in Japan after out-of-hospital cardiac arrest (OHCA, and we included 431 study patients. Propensity score analysis revealed that TTM at 32–34 °C decreased all-cause mortality in patients with rSO2 41–60%, and increased favorable neurological outcomes in patients with rSO2 41–60% in the original research article. With regard to the balance of covariates of propensity-score matching (PSM and inverse-probability weighting (IPW analyses, some covariates were not well balanced after the analyses between groups. The overlap plots indicate the overlap of densities of the propensity scores are low in group rSO2 41–60% and group rSO2 ≥ 61%. When patients were limited to those who achieved return of spontaneous circulation (ROSC until/on hospitals arrival, TTM still tended to decrease all-cause mortality and increase favorable outcomes in group rSO2 41–60%.

  13. 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)

    Tohgi, H.; Yonezawa, H.; Takahashi, S.; Sato, N.; Kato, E.; Kudo, M.; Hatano, K.; Sasaki, T.

    1998-01-01

    Regional cerebral blood flow (rCBF), cerebral metabolic rate of oxygen (rCMRO 2 ), 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, rCMRO 2 and rCBV were determined using C 15 O 2 , 15 O 2 and C 15 O, respectively. rCBF and CMRO 2 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.)

  14. 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.

  15. Assessment of pancreatic blood flow with positron emission tomography and oxygen-15 water

    International Nuclear Information System (INIS)

    Kubo, Soichi; Yamamoto, Kazutaka; Magata, Yasutaka; Iwasaki, Yasushi; Tamaki, Nagara; Yonekura, Yoshiharu; Konishi, Junji

    1991-01-01

    Dynamic positron emission tomography (PET) was performed following an intravenous bolus injection of 15 O-water for the assessment of regional pancreatic blood flow in 4 normal volunteers and 11 patients with pancreatic cancer. The regional pancreatic blood flow index (PFI) was calculated by the autoradiographic method assuming the time-activity curves of the aorta as an input function. The mean PFI value was 0.514±0.098 in the normal pancreas but it was decrease in the pancreatic cancer (0.247±0.076) (p 15 O-water permits quantitative assessment of pancreatic blood flow which decreased in both pancreatic cancer and concomitant obstructive pancreatitis distal to the tumor. (author)

  16. High blood oxygen affinity in the air-breathing swamp eel Monopterus albus.

    Science.gov (United States)

    Damsgaard, Christian; Findorf, Inge; Helbo, Signe; Kocagoz, Yigit; Buchanan, Rasmus; Huong, Do Thi Thanh; Weber, Roy E; Fago, Angela; Bayley, Mark; Wang, Tobias

    2014-12-01

    The Asian swamp eel (Monopterus albus, Zuiew 1793) is a facultative air-breathing fish with reduced gills. Previous studies have shown that gas exchange seems to occur across the epithelium of the buccopharyngeal cavity, the esophagus and the integument, resulting in substantial diffusion limitations that must be compensated by adaptations in others steps of the O₂ transport system to secure adequate O₂ delivery to the respiring tissues. We therefore investigated O₂ binding properties of whole blood, stripped hemoglobin (Hb), two major isoHb components and the myoglobin (Mb) from M. albus. Whole blood was sampled using indwelling catheters for blood gas analysis and determination of O₂ equilibrium curves. Hb was purified to assess the effects of endogenous allosteric effectors, and Mb was isolated from heart and skeletal muscle to determine its O₂ binding properties. The blood of M. albus has a high O₂ carrying capacity [hematocrit (Hct) of 42.4±4.5%] and binds O₂ with an unusually high affinity (P₅₀=2.8±0.4mmHg at 27°C and pH7.7), correlating with insensitivity of the Hb to the anionic allosteric effectors that normally decrease Hb-O₂ affinity. In addition, Mb is present at high concentrations in both heart and muscle (5.16±0.99 and 1.08±0.19mg ∙ g wet tissue⁻¹, respectively). We suggest that the high Hct and high blood O₂ affinity serve to overcome the low diffusion capacity in the relatively inefficient respiratory surfaces, while high Hct and Mb concentration aid in increasing the O₂ flux from the blood to the muscles. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Hepatic blood flow and splanchnic oxygen consumption in patients with liver failure. Effect of high-volume plasmapheresis.

    Science.gov (United States)

    Clemmesen, J O; Gerbes, A L; Gülberg, V; Hansen, B A; Larsen, F S; Skak, C; Tygstrup, N; Ott, P

    1999-02-01

    Liver failure represents a major therapeutic challenge, and yet basic pathophysiological questions about hepatic perfusion and oxygenation in this condition have been poorly investigated. In this study, hepatic blood flow (HBF) and splanchnic oxygen delivery (DO2, sp) and oxygen consumption (VO2,sp) were assessed in patients with liver failure defined as hepatic encephalopathy grade II or more. Measurements were repeated after high-volume plasmapheresis (HVP) with exchange of 8 to 10 L of plasma. HBF was estimated by use of constant infusion of D-sorbitol and calculated according to Fick's principle from peripheral artery and hepatic vein concentrations. In 14 patients with acute liver failure (ALF), HBF (1.78 +/- 0.78 L/min) and VO2,sp (3.9 +/- 0.9 mmol/min) were higher than in 11 patients without liver disease (1.07 +/- 0.19 L/min, P HVP, HBF increased from 1.67 +/- 0.72 to 2.07 +/- 1.11 L/min (n=11) in ALF, and from 1.89 +/- 1.32 to 2.34 +/- 1.54 L/min (n=7) in AOCLD, P HVP. Blood flow was redirected to the liver as the systemic vascular resistance index increased (1,587 +/- 650 vs. 2, 020 +/- 806 Dyne. s. cm-5. m2, P HVP, but as cardiac output increased from 9.1 +/- 2.8 to 10.1 +/- 2.9 L/min (P HVP (n=18), DO2,sp increased by 15% (P HVP. Changes of ET-1 were positively correlated with changes in HBF (P HVP (P HVP did not correlate. Our data suggest that liver failure is associated with increased HBF and VO2, sp. HVP further increased HBF and DO2,sp but VO2,sp was unchanged, indicating that splanchnic hypoxia was not present.

  18. Oxygen Therapy

    Directory of Open Access Journals (Sweden)

    Bonnie Solmes

    2000-01-01

    Full Text Available LTOT is prescribed for people with chronic lung disease in whom there is a decrease in the ability of the lungs to supply enough oxygen to the body. The heart is obliged to pump faster to meet the body's oxygen requirements. This may place undue stress on the heart, resulting in palpitations, dizziness and fatigue. A low oxygen level in arterial blood is also harmful to the heart, the brain and the pulmonary blood vessels. Oxygen therapy is used to break this cycle. A person with low blood oxygen will often be able to accomplish more with less fatigue with the help of supplemental oxygen therapy. Shortness of breath is a mechanical problem resulting from the effects of chronic obstructive pulmonary disease. Oxygen therapy may or may not reduce shortness of breath, but it will help the lungs and heart to function with less stress.

  19. Arterial blood gases and oxygen content in climbers on Mount Everest

    NARCIS (Netherlands)

    Grocott, Michael P. W.; Martin, Daniel S.; Levett, Denny Z. H.; McMorrow, Roger; Windsor, Jeremy; Montgomery, Hugh E.; Ahuja, V.; Aref-Adib, G.; Burnham, R.; Chisholm, A.; Clarke, K.; Coates, D.; Coates, M.; Cook, D.; Cox, M.; Dhillon, S.; Dougall, C.; Doyle, P.; Duncan, P.; Edsell, M.; Edwards, L.; Evans, L.; Gardiner, P.; Grocott, M.; Gunning, P.; Hart, N.; Harrington, J.; Harvey, J.; Holloway, C.; Howard, D.; Hurlbut, D.; Imray, C.; Ince, C.; Jonas, M.; van der Kaaij, J.; Khosravi, M.; Kolfschoten, N.; Levett, D.; Luery, H.; Luks, A.; Martin, D.; McMorrow, R.; Meale, P.; Mitchell, K.; Montgomery, H.; Morgan, G.; Morgan, J.; Murray, A.; Mythen, M.; Newman, S.

    2009-01-01

    BACKGROUND: The level of environmental hypobaric hypoxia that affects climbers at the summit of Mount Everest (8848 m [29,029 ft]) is close to the limit of tolerance by humans. We performed direct field measurements of arterial blood gases in climbers breathing ambient air on Mount Everest. METHODS:

  20. Contribution of blood oxygen and carbon dioxide sensing to the energetic optimization of human walking.

    Science.gov (United States)

    Wong, Jeremy D; O'Connor, Shawn M; Selinger, Jessica C; Donelan, J Maxwell

    2017-08-01

    People can adapt their gait to minimize energetic cost, indicating that walking's neural control has access to ongoing measurements of the body's energy use. In this study we tested the hypothesis that an important source of energetic cost measurements arises from blood gas receptors that are sensitive to O 2 and CO 2 concentrations. These receptors are known to play a role in regulating other physiological processes related to energy consumption, such as ventilation rate. Given the role of O 2 and CO 2 in oxidative metabolism, sensing their levels can provide an accurate estimate of the body's total energy use. To test our hypothesis, we simulated an added energetic cost for blood gas receptors that depended on a subject's step frequency and determined if subjects changed their behavior in response to this simulated cost. These energetic costs were simulated by controlling inspired gas concentrations to decrease the circulating levels of O 2 and increase CO 2 We found this blood gas control to be effective at shifting the step frequency that minimized the ventilation rate and perceived exertion away from the normally preferred frequency, indicating that these receptors provide the nervous system with strong physiological and psychological signals. However, rather than adapt their preferred step frequency toward these lower simulated costs, subjects persevered at their normally preferred frequency even after extensive experience with the new simulated costs. These results suggest that blood gas receptors play a negligible role in sensing energetic cost for the purpose of optimizing gait. NEW & NOTEWORTHY Human gait adaptation implies that the nervous system senses energetic cost, yet this signal is unknown. We tested the hypothesis that the blood gas receptors sense cost for gait optimization by controlling blood O 2 and CO 2 with step frequency as people walked. At the simulated energetic minimum, ventilation and perceived exertion were lowest, yet subjects

  1. The effect of exercise intensity and excess postexercise oxygen consumption on postprandial blood lipids in physically inactive men.

    Science.gov (United States)

    Littlefield, Laurel A; Papadakis, Zacharias; Rogers, Katie M; Moncada-Jiménez, José; Taylor, J Kyle; Grandjean, Peter W

    2017-09-01

    Reductions in postprandial lipemia have been observed following aerobic exercise of sufficient energy expenditure. Increased excess postexercise oxygen consumption (EPOC) has been documented when comparing high- versus low-intensity exercise. The contribution of EPOC energy expenditure to alterations in postprandial lipemia has not been determined. The purpose of this study was to evaluate the effects of low- and high-intensity exercise on postprandial lipemia in healthy, sedentary, overweight and obese men (age, 43 ± 10 years; peak oxygen consumption, 31.1 ± 7.5 mL·kg -1 ·min -1 ; body mass index, 31.8 ± 4.5 kg/m 2 ) and to determine the contribution of EPOC to reductions in postprandial lipemia. Participants completed 4 conditions: nonexercise control, low-intensity exercise at 40%-50% oxygen uptake reserve (LI), high-intensity exercise at 70%-80% oxygen uptake reserve (HI), and HI plus EPOC re-feeding (HI+EERM), where the difference in EPOC energy expenditure between LI and HI was re-fed in the form of a sports nutrition bar (Premier Nutrition Corp., Emeryville, Calif., USA). Two hours following exercise participants ingested a high-fat (1010 kcals, 99 g sat fat) test meal. Blood samples were obtained before exercise, before the test meal, and at 2, 4, and 6 h postprandially. Triglyceride incremental area under the curve was significantly reduced following LI, HI, and HI+EERM when compared with nonexercise control (p exercise conditions (p > 0.05). In conclusions, prior LI and HI exercise equally attenuated postprandial triglyceride responses to the test meal. The extra energy expended during EPOC does not contribute significantly to exercise energy expenditure or to reductions in postprandial lipemia in overweight men.

  2. Volume-dependent K+ transport in rabbit red blood cells comparison with oxygenated human SS cells

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rohil, N.; Jennings, M.L.

    1989-07-01

    In this study the volume-dependent or N-ethylmaleimide (NEM)-stimulated, ouabain-insensitive K+ influx and efflux were measured with the tracer 86Rb+ in rabbit red blood cells. The purpose of the work was to examine the rabbit as a potential model for cell volume regulation in human SS red blood cells and also to investigate the relationship between the NEM-reactive sulfhydryl group(s) and the signal by which cell swelling activates the transport. Ouabain-resistant K+ efflux and influx increase nearly threefold in cells swollen hypotonically by 15%. Pretreatment with 2 mM NEM stimulates efflux 5-fold and influx 10-fold (each measured in an isotonic medium). The ouabain-resistant K+ efflux was dependent on the major anion in the medium. The anion dependence of K+ efflux in swollen or NEM-stimulated cells was as follows: Br- greater than Cl- much greater than NO3- = acetate. The magnitudes of both the swelling- and the NEM-stimulated fluxes are much higher in young cells (density separated but excluding reticulocytes) than in older cells. Swelling- or NEM-stimulated K+ efflux in rabbit red blood cells was inhibited 50% by 1 mM furosemide, and the inhibitory potency of furosemide was enhanced by extracellular K+, as is known to be true for human AA and low-K+ sheep red blood cells. The swelling-stimulated flux in both rabbit and human SS cells has a pH optimum at approximately 7.4. We conclude that rabbit red blood cells are a good model for swelling-stimulated K+ transport in human SS cells.

  3. 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 J

    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 subcut......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 subcutaneous blood flow (QBF, SqBF) was assessed by Laser Doppler and 133Xe clearance. Tissue oxygen tension (TO(2)) was measured by a LICOX O(2)-electrode. Tissue glucose and lactate (Tgluc, Tlact) were assessed by microdialysis. The parameters were studied after intravenous infusion of 1.0 mg nicotine......, smoking of one cigarette, arterial occlusion, and reperfusion. RESULTS: Nicotine infusion decreased SqBF from 4.2 +/- 2.0 to 3.1 +/- 1.2 mL/100 g tissue/min (P

  4. Longitudinal Assessment of Renal Perfusion and Oxygenation in Transplant Donor-Recipient Pairs Using Arterial Spin Labeling and Blood Oxygen Level-Dependent Magnetic Resonance Imaging.

    Science.gov (United States)

    Niles, David J; Artz, Nathan S; Djamali, Arjang; Sadowski, Elizabeth A; Grist, Thomas M; Fain, Sean B

    2016-02-01

    The aims of this study were to assess renal function in kidney transplant recipients and their respective donors over 2 years using arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) and to prospectively evaluate the effect of losartan on functional MRI measures in recipients. The study included 15 matched pairs of renal transplant donors and recipients. Arterial spin labeling and BOLD MRI of the kidneys were performed on donors before transplant surgery (baseline) and on both donors and recipients at 3 months, 1 year, and 2 years after transplant. After 3 months, 7 of the 15 recipients were prescribed 25 to 50 mg/d losartan for the remainder of the study. A linear mixed-effects model was used to evaluate perfusion, R2*, estimated glomerular filtration rate, and fractional excretion of sodium for changes across time or associated with losartan treatment. In donors, cortical perfusion in the remaining kidney decreased by 50 ± 19 mL/min per 100 g (11.8%) between baseline and 2 years (P donors and to 14.6 ± 4.3 mL/min per 1.73 m (33.3%; P donors, and they indicate a potentially beneficial effect of losartan in recipients.

  5. Oxygen transfer properties and dimensions of red blood cells in high-altitude camelids, dromedary camel and goat.

    Science.gov (United States)

    Yamaguchi, K; Jürgens, K D; Bartels, H; Piiper, J

    1987-01-01

    To estimate the advantage of the small red blood cells (RBC) of high-altitude camelids for O2 transfer, the kinetics of O2 uptake into and release from the RBC obtained from llama, vicuña and alpaca were investigated at 37 degrees C with a stopped-flow technique. O2 transfer conductance of RBC (G) was estimated from the rate of O2 saturation change and the corresponding O2 pressure difference between medium and hemoglobin. For comparison, O2 kinetics for the RBC of a low-altitude camelid (dromedary camel) and the pygmy goat were determined and previously measured values for human RBC were used. O2 transfer of RBC was found to be strongly influenced by extracellular diffusion, except with O2 release into dithionite solutions of sufficiently high concentration (greater than 30 mM). The G values measured in these 'standard' conditions, Gst (in mmol X min-1 X Torr-1 X (ml RBC)-1) were: high-altitude camelids, 0.58 (averaged for llama, alpaca and vicuña since there were no significant interspecific differences); camel 0.42; goat, 0.42; man, 0.39. The differences can in part be attributed to expected effects of the size and shape of the RBC (volume, surface area, mean thickness), as well as to the intracellular O2 diffusivity which depends on the concentration of cellular hemoglobin. The high Gst of RBC of high-altitude camelids may be considered to enhance O2 transfer in lungs and tissues. But the O2 transfer conductance of blood, theta, equal to Gst multiplied by hematocrit (in mmol X min-1 X Torr-1 X (ml blood)-1), was only slightly higher as compared to other species: 0.20 (llama, alpaca, vicuña), 0.14 (camel), 0.18 (goat), 0.17 (man).

  6. Soil aquifer treatment of artificial wastewater under saturated conditions

    KAUST Repository

    Essandoh, H. M K; Tizaoui, Chedly; Mohamed, Mostafa H A; Amy, Gary L.; Brdjanovic, Damir

    2011-01-01

    A 2000 mm long saturated laboratory soil column was used to simulate soil aquifer treatment under saturated conditions to assess the removal of chemical and biochemical oxygen demand (COD and BOD), dissolved organic carbon (DOC), nitrogen

  7. Relationship between relative cerebral blood flow, relative cerebral blood volume, and relative cerebral metabolic rate of oxygen in the preterm neonatal brain.

    Science.gov (United States)

    Nourhashemi, Mina; Kongolo, Guy; Mahmoudzadeh, Mahdi; Goudjil, Sabrina; Wallois, Fabrice

    2017-04-01

    The mechanisms responsible for coupling between relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), and relative cerebral metabolic rate of oxygen ([Formula: see text]), an important function of the microcirculation in preterm infants, remain unclear. Identification of a causal relationship between rCBF-rCBV and [Formula: see text] in preterms may, therefore, help to elucidate the principles of cortical hemodynamics during development. We simultaneously recorded rCBF and rCBV and estimated [Formula: see text] by two independent acquisition systems: diffuse correlation spectroscopy and near-infrared spectroscopy, respectively, in 10 preterms aged between 28 and 35 weeks of gestational age. Transfer entropy was calculated in order to determine the directionality between rCBF-rCBV and [Formula: see text]. The surrogate method was applied to determine statistical significance. The results show that rCBV and [Formula: see text] have a predominant driving influence on rCBF at the resting state in the preterm neonatal brain. Statistical analysis robustly detected the correct directionality of rCBV on rCBF and [Formula: see text] on rCBF. This study helps to clarify the early organization of the rCBV-rCBF and [Formula: see text] inter-relationship in the immature cortex.

  8. Mannitol increases renal blood flow and maintains filtration fraction and oxygenation in postoperative acute kidney injury: a prospective interventional study.

    Science.gov (United States)

    Bragadottir, Gudrun; Redfors, Bengt; Ricksten, Sven-Erik

    2012-08-17

    Acute kidney injury (AKI), which is a major complication after cardiovascular surgery, is associated with significant morbidity and mortality. Diuretic agents are frequently used to improve urine output and to facilitate fluid management in these patients. Mannitol, an osmotic diuretic, is used in the perioperative setting in the belief that it exerts reno-protective properties. In a recent study on uncomplicated postcardiac-surgery patients with normal renal function, mannitol increased glomerular filtration rate (GFR), possibly by a deswelling effect on tubular cells. Furthermore, experimental studies have previously shown that renal ischemia causes an endothelial cell injury and dysfunction followed by endothelial cell edema. We studied the effects of mannitol on renal blood flow (RBF), glomerular filtration rate (GFR), renal oxygen consumption (RVO2), and extraction (RO2Ex) in early, ischemic AKI after cardiac surgery. Eleven patients with AKI were studied during propofol sedation and mechanical ventilation 2 to 6 days after complicated cardiac surgery. All patients had severe heart failure treated with one (100%) or two (73%) inotropic agents and intraaortic balloon pump (36%). Systemic hemodynamics were measured with a pulmonary artery catheter. RBF and renal filtration fraction (FF) were measured by the renal vein thermo-dilution technique and by renal extraction of chromium-51-ethylenediaminetetraacetic acid (51Cr-EDTA), respectively. GFR was calculated as the product of FF and renal plasma flow RBF × (1-hematocrit). RVO2 and RO2Ex were calculated from arterial and renal vein blood samples according to standard formulae. After control measurements, a bolus dose of mannitol, 225 mg/kg, was given, followed by an infusion at a rate of 75 mg/kg/h for two 30-minute periods. Mannitol did not affect cardiac index or cardiac filling pressures. Mannitol increased urine flow by 61% (P renal vascular resistance (P renal FF. Mannitol treatment of postoperative AKI

  9. Assessment of cerebral blood flow reserve using blood oxygen level-dependent echo planar imaging after acetazolamide administration in patients post-STA-MCA anastomosis surgery

    International Nuclear Information System (INIS)

    Zenke, Kiichiro; Kusunoki, Katsusuke; Saito, Masahiro; Sadamoto, Kazuhiko; Ohta, Shinsuke; Kumon, Yoshiaki; Sakaki, Saburo; Nagasawa, Kiyoshi

    1998-01-01

    Recently, blood oxygen level-dependent (BOLD) echo planar imaging (EPI) has been used to estimate blood flow changes. Theoretically, a relative decrement of deoxyhemoglobin in cerebral blood supply induces a MR signal change after neuronal stimulation. In the present study, we have attempted to evaluate CBF reserve capacity by the BOLD EPI in patients who had undergone STA-MCA anastomosis surgery. Then, we compared with the signal intensity changes obtained by this procedure with the CBF changes by Xe-SPECT after acetazolamide administration. Six patients, post-STA-MCA anastomosis surgery, were studied. Pre-operatively, MR signal intensity and CBF, by Xe-SPECT, were increased in the intact side after acetazolamide administration in all patients, and MR signal intensities were decreased in low flow regions after acetazolamide administration in all four patients in whom so-called steal phenomenon was demonstrated by Xe-SPECT study. Post-operatively, poor response was shown after acetazolamide administration with both Xe-SPECT and BOLD EPI in the two patients who had unsuccessful anastomoses. In the successfully anastomosed patients, improved vascular reactivity was demonstrated on BOLD EPI after acetazolamide administration in 3 of 4 patients in whom an improvement of vascular reactivity was demonstrated on Xe-SPECT. In one patient, MRI studies were considered to have technical artifacts, because the MR signal intensity did not increase, even in the intact side after acetazolamide administration. In conclusion, BOLD EPI after acetazolamide administration is an useful procedure for the pre- and post-operative of vascular reserve in patients with ischemic stroke. (author)

  10. Influence of blood flow occlusion on muscle oxygenation characteristics and the parameters of the power-duration relationship.

    Science.gov (United States)

    Broxterman, R M; Ade, C J; Craig, J C; Wilcox, S L; Schlup, S J; Barstow, T J

    2015-04-01

    It was previously (Monod H, Scherrer J. Ergonomics 8: 329-338, 1965) postulated that blood flow occlusion during exercise would reduce critical power (CP) to 0 Watts (W), while not altering the curvature constant (W'). We empirically assessed the influence of blood flow occlusion on CP, W', and muscle oxygenation characteristics. Ten healthy men (age: 24.8 ± 2.6 yr; height: 180 ± 5 cm; weight: 84.6 ± 10.1 kg) completed four constant-power handgrip exercise tests during both control blood flow (control) and blood flow occlusion (occlusion) for the determination of the power-duration relationship. Occlusion CP (-0.7 ± 0.4 W) was significantly (P < 0.001) lower than control CP (4.1 ± 0.7 W) and significantly (P < 0.001) lower than 0 W. Occlusion W' (808 ± 155 J) was significantly (P < 0.001) different from control W' (558 ± 129 J), and all 10 subjects demonstrated an increased occlusion W' with a mean increase of ∼49%. The present findings support the aerobic nature of CP. The findings also demonstrate that the amount of work that can be performed above CP is constant for a given condition, but can vary across conditions. Moreover, this amount of work that can be performed above CP does not appear to be the determinant of W', but rather a consequence of the depletion of intramuscular energy stores and/or the accumulation of fatigue-inducing metabolites, which limit exercise tolerance and determine W'. Copyright © 2015 the American Physiological Society.

  11. Whole-brain blood flow and oxygen metabolism in the rat after halothane anesthesia

    Energy Technology Data Exchange (ETDEWEB)

    Gjedde, A; Hindfeldt, B [Cerebrovascular Research Center, Department of Neurology, The New York Hospital-Cornell Medical Center, New York, U.S.A.; Department of Neurology, University Hospital, Lund, Sweden)

    1975-01-01

    A recent modification of the Kety-Schmidt wash-out technique for /sup 133/xenon was used to measure whole-brain flow (CBF) and oxygen consumption (CMRsub(o2)) 1 to 4 hours after termination of halothane anesthesia in 15 Wistar rats. In this 3-hour experimental period, mean CBF and CMRsub(o2) were reduced to 29 and 43 percent of control values, respectively. CBF and CMRsub(o2) determined at the beginning and end of the experimental period were not significantly different from each other. Cerebral venous O/sub 2/ tension was significantly higher than in the control group, supporting recent suggestions of a primary, intrinsic effect of halothane on the homeostatic control of this variable. It is concluded that halothane is not useful for cerebral metabolic studies in the rat.

  12. Significant and sustaining elevation of blood oxygen induced by Chinese cupping therapy as assessed by near-infrared spectroscopy.

    Science.gov (United States)

    Li, Ting; Li, Yaoxian; Lin, Yu; Li, Kai

    2017-01-01

    Cupping therapy has been used in traditional Chinese medicine for thousands of years to relieve muscle pain/tendency/fatigue and to cure or reduce symbols of other diseases. However, its therapeutic effect is sparsely interpreted in the language of modern physiology. To objectively evaluate its therapeutic effect, we focused on dry cupping treatment and utilized near-infrared spectroscopy (NIRS) to assess the concentration change in oxy-hemoglobin ([HbO 2 ]), deoxy-hemoglobin ([Hb]), and blood volume in the course of cupping therapy over 13 volunteers on the infraspinatus muscle, where is usually applied for shoulder pains. Both a prominent drop in [Hb] and a significant elevation in [HbO 2 ] in the tissue surrounding the cupping site were observed during both cupping and post-treatment, manifesting the enhancement of oxygen uptake. This resulting promotion indicates potential positive therapeutic effect of cupping therapy in hemodynamics for facilitating muscular functions.

  13. Measurement of local blood flow and oxygen consumption in evolving irreversible cerebral infarction: an in vivo study in man

    International Nuclear Information System (INIS)

    Baron, J.C.; Rougemont, D.; Lebrun-Grandie, P.; Bousser, M.G.; Cabanis, E.; Bories, J.; Comar, D.; Castaigne, P.

    1982-09-01

    Positron emission tomography (PET) allows in vivo measurement of local cerebral blood flow (1CBF), oxygen consumption rate (1CMRO 2 ) and glucose utilisation (1CMRG1c) in man. Although 1CMRG1c is accessible in animals, this is not the case for 1CMRO 2 , 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-CMRO 2 quantitative patterns in irreversibly infarcted brain regions

  14. 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.

  15. The air we breathe: three vital respiratory gases and the red blood cell: oxygen, nitric oxide, and carbon dioxide.

    Science.gov (United States)

    Dzik, Walter H

    2011-04-01

    Three vital respiratory gases-oxygen (O(2)), nitric oxide (NO), and carbon dioxide (CO(2))-intersect at the level of the human red blood cell (RBC). In addition to hemoglobin (Hb)'s central role in O(2) transport, interaction of Hb with the Band 3 metabolon balances RBC energy flow. 2,3-Diphosphoglycerate enhances O(2) transport across the placenta and plays an important role in regulating RBC plasticity. NO is a key mediator of hypoxic vasodilation, but the precise role of RBC Hb remains controversial. In addition to established theories that depend on RBC uptake, delivery, and discharge of NO or its metabolites, an alternative hypothesis based on RBC permeability is suggested. NO depletion by free Hb may account for several clinical features seen during intravascular hemolysis or during deliberate infusion of Hb solutions used as RBC substitutes. CO(2) released by tissues triggers oxygen release through a series of well-coordinated reactions centered on the Band 3 metabolon. While RBC carbonic anhydrase and the Band 3 anion exchanger are central to this process, there is surprisingly little research on the kinetics of CO(2) clearance by transfusion. The three RBC gases are directly related to the three principal gases of Earth's atmosphere. Human fossil fuel consumption dumps 90 million metric tons of carbon into the atmosphere annually. Increasing CO(2) levels are linked to global warming, melting Arctic ice, rising sea levels, and climate instability. Just as individual cells depend on balance of the three vital gases, so too will their balance determine survival of life on Earth. © 2011 American Association of Blood Banks.

  16. 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.

  17. 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...

  18. The relationship between the cerebral blood flow, oxygen consumption and glucose metabolism in primary degenerative dementia

    International Nuclear Information System (INIS)

    Kuwabara, Yasuo; Ichiya, Yuichi; Ichimiya, Atsushi; Sasaki, Masayuki; Akashi, Yuko; Yoshida, Tsuyoshi; Fukumura, Toshimitsu; Masada, Kouji

    1995-01-01

    The CBF, CMRO 2 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, CMRO 2 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 CMRO 2 were closely correlated with each other. However, the CMRGlu was more severely impaired than the CBF or CMRO 2 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)

  19. Average blood flow and oxygen uptake in the human brain during resting wakefulness

    DEFF Research Database (Denmark)

    Madsen, P L; Holm, S; Herning, M

    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...... the measured data, we find that the true average values for CBF and CMRO2 in the healthy young adult are approximately 46 ml 100 g-1 min-1 and approximately 3.0 ml 100 g-1 min-1. Previous studies have suggested that some of the variation in CMRO2 values could be ascribed to differences in cerebral venous...

  20. [Effect of hemodilution with 10% hydroxyethyl starch solution (MW 200,000/9.5) on the flow properties of blood, arterial blood gases and conjunctival oxygen partial pressure in patients with cerebral infarct].

    Science.gov (United States)

    Staedt, U; Hütt, M; Herrmann, B; Seufzer, U; Leweling, H

    1989-06-01

    Hemorheological parameters, arterial blood gases and conjunctival oxygen tension were measured in 15 patients with acute ischemic stroke and compared with values obtained in an age matched reference group. Since the conjunctival capillary bed is perfused by the ophthalmic artery, it reflects the oxygen delivery to the areas supplied by the internal carotid artery. Measurements of conjunctival oxygen tension are simple and safe. Patients with acute ischemic stroke showed a lowered conjunctival oxygen tension; this holds true especially to the ipsilateral side, i.e. the side where the attack occurred, and to a lesser extent to the other side. By contrast, the ratio of arterial/conjunctival pO2 was disturbed only on the ipsilateral side. Furthermore, these patients had pathologically elevated values for red cell aggregation, whole blood and plasma viscosity. After infusing 500 ml 10% middle-molecular-weight hydroxyethyl starch (10% HAES-steril) and phlebotomy (250 ml) blood fluidity was normalized, although the hematokrit was only slightly reduced. Arterial pO2 improved slightly while pCO2 remained unchanged. Conjunctival oxygen tension improved by 30% on the ipsilateral and by 10% on the contralateral side, the ipsilateral values always remaining significantly lower. The ratio conjunctival/arterial pO2 raised only on the ipsilateral side where it was below the reference range before hemodilution. In addition to the well known improvement of blood fluidity and augmentation of cerebral blood flow following hemodilution in patients with acute ischemic stroke, there seems to be an increase in oxygen supply in the territories of both internal carotid arteries, especially on the ipsilateral side as indicated by the values of conjunctival oxygen tension and the ratio of conjunctival to arterial pO2.