Is oxygen supplementation necessary for patients under spinal ...

African Journals Online (AJOL)

Background: Oxygen supplementation is given routinely to patients undergoing surgery under spinal anaesthesia, the basic aim being to prevent oxygen desaturation and hypoxemia. Objective: This study aimed to find out the incidence of hypoxemia under spinal anaesthesia and determine if oxygen supplementation is ...

Association between morphometric variables and nocturnal desaturation in sickle-cell anemia.

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Salles, Cristina; Bispo, Marcelo; Trindade-Ramos, Regina Terse

2014-01-01

to evaluate associations between morphometric variables, cervical circumference (CC), and abdominal circumference (AC) with the presence of nocturnal desaturation in children and adolescents with sickle-cell anemia. all patients were submitted to baseline polysomnography, oral cavity measurements (maxillary intermolar distance, mandibular intermolar distance, and overjet), and CC and AC measurements. a total of 85 patients were evaluated. A positive correlation was observed between the height/age Z-score and CC measurement (r = 0.233, p = 0.031). The presence of nocturnal desaturation was associated with CC (59.2± 9.3 vs. 67.5 ± 10.7, p = 0.006) and AC measurements (27.0 ± 2.0 vs. 29.0± 2.1, p = 0.028). There was a negative correlation between desaturation and maxillary intermolar distance (r = -0.365, p = 0.001) and mandibular intermolar distance (r = -0.233, p = 0.037). the morphometric variables of CC and AC may contribute to raise suspicion of nocturnal desaturation in children and adolescents with sickle-cell anemia. Copyright © 2014 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Association between morphometric variables and nocturnal desaturation in sickle-cell anemia

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Cristina Salles

2014-07-01

Full Text Available OBJECTIVE: to evaluate associations between morphometric variables, cervical circumference (CC, and abdominal circumference (AC with the presence of nocturnal desaturation in children and adolescents with sickle-cell anemia. METHODS: all patients were submitted to baseline polysomnography, oral cavity measurements (maxillary intermolar distance, mandibular intermolar distance, and overjet, and CC and AC measurements. RESULTS: a total of 85 patients were evaluated. A positive correlation was observed between the height/age Z-score and CC measurement (r = 0.233, p = 0.031. The presence of nocturnal desaturation was associated with CC (59.2± 9.3 vs. 67.5 ± 10.7, p = 0.006 and AC measurements (27.0 ± 2.0 vs. 29.0± 2.1, p = 0.028. There was a negative correlation between desaturation and maxillary intermolar distance (r = -0.365, p = 0.001 and mandibular intermolar distance (r = -0.233, p = 0.037. CONCLUSIONS: the morphometric variables of CC and AC may contribute to raise suspicion of nocturnal desaturation in children and adolescents with sickle-cell anemia.

Effect of race distance on muscle oxygenation in short-track speed skating.

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Hesford, Catherine M; Laing, Stewart; Cardinale, Marco; Cooper, Chris E

2013-01-01

Previous work identified an asymmetry in tissue desaturation changes in the left and right quadriceps muscles during on-ice skating at maximal speed in males. The effect of changing race distance on the magnitude of desaturation or leg asymmetry is unknown. Six elite male skaters (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm) and four elite female skaters (age = 21 ± 4 yr, height = 1.6 ± 0.1 m, mass = 65.2 ± 4.3 kg, midthigh skinfold thickness = 10 ± 1 mm) were studied. Subjects completed time trials over three race distances. Blood lactate concentration and O2 uptake measurements were combined with near-infrared spectroscopy measures of muscle oxygenation (TSI) and blood volume (tHb) in the right and left vastus lateralis. Neither race distance nor gender had a significant effect on the magnitude of maximal muscle desaturation (ΔTSI(max)). Pattern of local changes in tHb during individual laps was dependent upon subtle differences in skating technique used for the different race distances. Linear regression analysis revealed asymmetry between the right and left leg desaturation in males during the final stages of each race distance, but not in females. At all race distances, local muscle desaturation reached maximal values much more quickly than global VO(2peak). The use of wearable near-infrared spectroscopy devices enabled measurement of muscle oxygenation during competitive race simulation, thus providing unique insight into the effects of velocity and technique changes on local muscle oxygenation. This may have implications for training and race pacing in speed skating.

Effect of desaturation and re-saturation on shale in underground galleries

International Nuclear Information System (INIS)

Pham, Q.T.

2006-03-01

The aim of this thesis is to characterize by experimental and numerical approaches the hydric, mechanical and hydro-mechanical effects due to the desaturation and re-saturation of the Eastern argillite, host rock of the Bure site, future underground radioactive waste disposal facility. Experimental and numerical approaches for the characterization of hydric transfers in argilites are presented. A simple identification method is proposed which uses the determination of the linearized hydric diffusivity from weight measurements performed on samples (thin tubes and plates) submitted to humidity steps according to a desaturation-re-saturation cycle. The hydric transfer is nonlinear. In order to interpret this phenomenon, a non-linear numerical model is established which takes into account the physical phenomena (hydraulic conduction, vapor diffusion, phase change..). The evolution of the physical and mechanical behaviour of the argillaceous rock with respect to the imposed humidity is then analyzed according to a desaturation-re-saturation cycle by successive steps. The hydric deformation, the velocity of ultrasonic waves propagation, the elastic properties, the rupture characteristics and the delayed phenomena depend on the hydric state of the material. The desaturation and re-saturation influence on a scale model of tunnel is analyzed. Thick tubes parallel or perpendicular to the stratification are used to show up the anisotropy of the rock. These tubes are submitted to hydric loads by blowing air with variable hygrometry through their center hole. A nonlinear poro-elastic model is used to interpret the anisotropic hydro-mechanical phenomena observed. It is shown that hydric loads can lead to the rupture of test samples which follow the anisotropic directions of the rock and which can be interpreted by the hydro-mechanical model as a violation of a rupture criterion in total pulling stress. Finally, numerical calculations for the phenomena generated by desaturation

Effect of desaturation and re-saturation on shale in underground galleries; Effets de la desaturation et de la resaturation sur l'argilite dans les ouvrages souterrains

Energy Technology Data Exchange (ETDEWEB)

Pham, Q.T

2006-03-15

The aim of this thesis is to characterize by experimental and numerical approaches the hydric, mechanical and hydro-mechanical effects due to the desaturation and re-saturation of the Eastern argillite, host rock of the Bure site, future underground radioactive waste disposal facility. Experimental and numerical approaches for the characterization of hydric transfers in argilites are presented. A simple identification method is proposed which uses the determination of the linearized hydric diffusivity from weight measurements performed on samples (thin tubes and plates) submitted to humidity steps according to a desaturation-re-saturation cycle. The hydric transfer is nonlinear. In order to interpret this phenomenon, a non-linear numerical model is established which takes into account the physical phenomena (hydraulic conduction, vapor diffusion, phase change..). The evolution of the physical and mechanical behaviour of the argillaceous rock with respect to the imposed humidity is then analyzed according to a desaturation-re-saturation cycle by successive steps. The hydric deformation, the velocity of ultrasonic waves propagation, the elastic properties, the rupture characteristics and the delayed phenomena depend on the hydric state of the material. The desaturation and re-saturation influence on a scale model of tunnel is analyzed. Thick tubes parallel or perpendicular to the stratification are used to show up the anisotropy of the rock. These tubes are submitted to hydric loads by blowing air with variable hygrometry through their center hole. A nonlinear poro-elastic model is used to interpret the anisotropic hydro-mechanical phenomena observed. It is shown that hydric loads can lead to the rupture of test samples which follow the anisotropic directions of the rock and which can be interpreted by the hydro-mechanical model as a violation of a rupture criterion in total pulling stress. Finally, numerical calculations for the phenomena generated by desaturation

Research on Single-Phase PWM Converter with Reverse Conducting IGBT Based on Loss Threshold Desaturation Control

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Xianjin Huang

2017-11-01

Full Text Available In the application of vehicle power supply and distributed power generation, there are strict requirements for the pulse width modulation (PWM converter regarding power density and reliability. When compared with the conventional insulated gate bipolar transistor (IGBT module, the Reverse Conducting-Insulated Gate Bipolar Transistor (RC-IGBT with the same package has a lower thermal resistance and higher current tolerance. By applying the gate desaturation control, the reverse recovery loss of the RC-IGBT diode may be reduced. In this paper, a loss threshold desaturation control method is studied to improve the output characteristics of the single-phase PWM converter with a low switching frequency. The gate desaturation control characteristics of the RC-IGBT’s diode are studied. A proper current limit is set to avoid the ineffective infliction of the desaturation pulse, while the bridge arm current crosses zero. The expectation of optimized loss decrease is obtained, and the better performance for the RC-IGBTs of the single-phase PWM converter is achieved through the optimized desaturation pulse distribution. Finally, the improved predictive current control algorithm that is applied to the PWM converter with RC-IGBTs is simulated, and is operated and tested on the scaled reduced power platform. The results prove that the gate desaturation control with the improved predictive current algorithm may effectively improve the RC-IGBT’s characteristics, and realize the stable output of the PWM converter.

Organ-Specific Alterations in Fatty Acid De Novo Synthesis and Desaturation in a Rat Model of Programmed Obesity

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Desai Mina

2011-05-01

Full Text Available Abstract Background Small for gestational age (SGA leads to increased risk of adult obesity and metabolic syndrome. Offspring exposed to 50% maternal food restriction in utero are born smaller than Controls (FR, catch-up in growth by the end of the nursing period, and become obese adults. The objective of the study was to determine stearoyl-CoA desaturase activity (SCD1 and rates of de novo fatty acid synthesis in young FR and Control offspring tissues at the end of the nursing period, as possible contributors to catch-up growth. Methods From gestational day 10 to term, dams fed ad libitum (Control or were 50% food-restricted to produce small FR pups. Control dams nursed all pups. At postnatal day 1 (p1 and p21, offspring body tissues were analyzed by GC/MS, and desaturation indices of palmitoleate/palmitate and oleate/stearate were calculated. SCD1 gene expression was determined by real-time PCR on adipose and liver. Offspring were enriched with deuterium that was given to dams in drinking water during lactation and de novo synthesis of offspring body tissues was determined at p21. Primary adipocyte cell cultures were established at p21 and exposed to U13C-glucose. Results FR offspring exhibited higher desaturation index in p1 and p21 adipose tissue, but decreased desaturation index in liver at p21. SCD1 gene expression at p21 was correspondingly increased in adipose and decreased in liver. FR subcutaneous fat demonstrated increased de novo synthesis at p21. Primary cell cultures exhibited increased de novo synthesis in FR. Conclusions Adipose tissue is the first site to exhibit increased de novo synthesis and desaturase activity in FR. Therefore, abnormal lipogenesis is already present prior to onset of obesity during the period of catch-up growth. These abnormalities may contribute to future obesity development.

Predictive factors of oxygen desaturation of patients submitted to endoscopic retrograde cholangiopancreatography under conscious sedation Fatores preditivos de dessaturação de oxigênio de pacientes submetidos a colangiopancreatografia endoscópica retrógrada sob sedação consciente

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Suzana Müller

2004-09-01

Full Text Available BACKGROUND AND AIMS: Hypoxemia can occur during endoscopic retrograde cholangiopancreatography probably induced by the analgesia and sedation done. Moreover the patient’s prone position difficults the adequate ventilation. The hypoxemia and hypoventilation may not be noticed by nursing staff. A transversal study was used to investigate possible predictive factors of oxygen desaturation in sedated patients with midazolam associated to meperidine undergoing endoscopic retrograde cholangiopancreatography. PATIENTS AND METHODS: A total of 186 patients were monitored with continuous pulse oximetry. Poisson regression was used to measure the independent effect of each factor adjusted for effects of each of the other factors. The variables studied were: age, gender, hematocrit and hemoglobin levels, scopolamine use, diagnostic or therapeutic exam, American Society of Anesthesiologists Scores (ASA, duration time of exam, sedative used midazolam in the average of 0.07 mg/kg and analgesic drug meperidine in the average of 0.7 mg/kg that was titrated according patient’s reaction. RESULTS: No desaturation was found in 113 (60.8% patients, mild desaturation (SpO2 60 years old and ASA score III. The duration of exam was barely significant for desaturation. CONCLUSIONS:The variables of age of 60 years old or more, and ASA III score are identified as increased risk for desaturation for patients who undergo endoscopic retrograde cholangiopancreatography under conscious sedation. Long time of exam suggests the patient oxygen desaturate. Such patients require very close monitoring to desaturation and hypoventilation by the assistants and nursing staff alerting to respiratory depression. The use of pulse oximeter and asking for deep breaths during the exam helps to diminish such risks.RACIONAL: A hipoxemia pode ocorrer durante a colangiopancreatografia endoscópica retrógrada, provavelmente induzida pela analgesia e sedação realizadas, além da posição do

Cerebral oxygenation in patients undergoing shoulder surgery in beach chair position: comparing general to regional anesthesia and the impact on neurobehavioral outcome.

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Aguirre, J; Borgeat, A; Trachsel, T; Cobo Del Prado, I; De Andrés, J; Bühler, P

2014-02-01

Ischemic brain damage has been reported in healthy patients after beach chair position for surgery due to cerebral hypoperfusion. Near-infrared spectroscopy has been described as a non-invasive, continuous method to monitor cerebral oxygen saturation. However, its impact on neurobehavioral outcome comparing different anesthesia regimens has been poorly described. In this prospective, assessor-blinded study, 90 patients undergoing shoulder surgery in beach chair position following general (G-group, n=45) or regional anesthesia (R-group; n=45) were enrolled to assess the prevalence of cerebral desaturation events comparing anesthesia regimens and their impact on neurobehavioral and neurological outcome. Anesthesiologists were blinded to regional cerebral oxygen saturation values. Baseline data assessed the day before surgery included neurological and neurobehavioral tests, which were repeated the day after surgery. The baseline data for regional cerebral oxygen saturation/bispectral index and invasive blood pressure both at heart and auditory meatus levels were taken prior to anesthesia, 5 min after induction of anesthesia, 5 min after beach chair positioning, after skin incision and thereafter all 20 min until discharge. Patients in the R-group showed significantly less cerebral desaturation events (psurgery (pshoulder surgery in beach chair position influencing neurobehavioral test results at 24h. Copyright © 2013 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

Pilot study of a new device to titrate oxygen flow in hypoxic patients on long-term oxygen therapy.

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Cirio, Serena; Nava, Stefano

2011-04-01

The O(2) Flow Regulator (Dima, Bologna, Italy) is a new automated oxygen regulator that titrates the oxygen flow based on a pulse-oximetry signal to maintain a target S(pO(2)). We tested the device's safety and efficacy. We enrolled 18 subjects with chronic lung disease, exercise-induced desaturation, and on long-term oxygen therapy, in a randomized crossover study with 2 constant-work-load 15-min cycling exercise tests, starting with the patient's previously prescribed usual oxygen flow. In one test the oxygen flow was titrated manually by the respiratory therapist, and in the other test the oxygen flow was titrated by the O(2) Flow Regulator, to maintain an S(pO(2)) of 94%. We measured S(pO(2)) throughout each test, the time spent by the respiratory therapist to set the device or to manually regulate the oxygen flow, and the total number of respiratory-therapist titration interventions during the trial. There were no differences in symptoms or heart rate between the exercise tests. Compared to the respiratory-therapist-controlled tests, during the O(2) Flow Regulator tests S(pO(2)) was significantly higher (95 ± 2% vs 93 ± 3%, P = .04), significantly less time was spent below the target S(pO(2)) (171 ± 187 s vs 340 ± 220 s, P less respiratory therapist time (5.6 ± 3.7 min vs 2.0 ± 0.1 min, P = .005). The O(2) Flow Regulator may be a safe and effective alternative to manual oxygen titration during exercise in hypoxic patients. It provided stable S(pO(2)) and avoided desaturations in our subjects.

Oxygen titration after resuscitation from out-of-hospital cardiac arrest: a multi-centre, randomised controlled pilot study (the EXACT pilot trial).

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Bray, Janet E; Hein, Cindy; Smith, Karen; Stephenson, Michael; Grantham, Hugh; Finn, Judith; Stub, Dion; Cameron, Peter

2018-04-20

Recent studies suggest the administration of 100% oxygen to hyperoxic levels following return-of-spontaneous-circulation (ROSC) post-cardiac arrest may be harmful. However, the feasibility and safety of oxygen titration in the prehospital setting is unknown. We conducted a multi-centre, phase-2 study testing whether prehospital titration of oxygen results in an equivalent number of patients arriving at hospital with oxygen saturations SpO2 ≥ 94%. We enrolled unconscious adults with: sustained ROSC; initial shockable rhythm; an advanced airway; and an SpO2 ≥ 95%. Initially (Sept 2015-March 2016) patients were randomised 1:1 to either 2 litres/minute (L/min) oxygen (titrated) or >10 L/min oxygen (control) via a bag-valve reservoir. However, one site experienced a high number of desaturations (SpO2 titrated arm and this arm was changed (April 2016) to an initial reduction of oxygen to 4 L/min then, if tolerated, to 2 L/min, and the desaturation limit was decreased to titrated (n = 37: 2L/min = 20 and 2-4 L/min = 17) oxygen or control (n = 24). Patients allocated to titrated oxygen were more likely to desaturate compared to controls ((SpO2 titrated: 90% vs. control: 100%) and all patients had a SpO2 ≥ 90%. One patient (control) re-arrested. Survival to hospital discharge was similar. Oxygen titration post-ROSC is feasible in the prehospital environment, but incremental titration commencing at 4L/min oxygen flow may be needed to maintain an oxygen saturation >90% (NCT02499042). Copyright © 2018. Published by Elsevier B.V.

The Predictors of Obesity Hypoventilation Syndrome in Obstructive Sleep Apnea

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Aylin Pıhtılı

2017-02-01

Full Text Available Background: As obesity increases, the frequency of obstructive sleep apnea and obesity hypoventilation syndrome increases also. However, obesity hypoventilation syndrome frequency is not known, as capnography and arterial blood gas analysis are not routinely performed in sleep laboratories. Aims: To investigate the frequency and predictors of obesity hypoventilation syndrome in obese subjects. Study Design: Retrospective clinical study Methods: Obese subjects who had arterial blood gas analysis admitted to the sleep laboratory and polysomnography were retrospectively analyzed. Subjects with restrictive (except obesity and obstructive pulmonary pathologies were excluded. Demographics, Epworth-Sleepiness-Scale scores, polysomnographic data, arterial blood gas analysis, and spirometric measurements were recorded. Results: Of the 419 subjects, 45.1% had obesity hypoventilation syndrome. Apnea hypopnea index (p<0.001, oxygen desaturation index (p<0.001 and sleep time with SpO2<90% (p<0.001 were statistically higher in subjects with obesity hypoventilation syndrome compared to subjects with eucapnic obstructive sleep apnea. The nocturnal mean SpO2 (p<0.001 and lowest SpO2 (p<0.001 were also statistically lower in subjects with obesity hypoventilation syndrome. Logistic regression analysis showed that the lowest SpO2, oxygen desaturation index, apnea hypopnea index and sleep time with SpO2 <90% were related factors for obesity hypoventilation syndrome. Conclusion: Obesity hypoventilation syndrome should be considered when oxygen desaturation index, apnea hypopnea index and sleep time with SpO2 <90% are high

Bicarbonate attenuates arterial desaturation during maximal exercise in humans

DEFF Research Database (Denmark)

Nielsen, Henning B; Bredmose, Per P; Strømstad, Morten

2002-01-01

The contribution of pH to exercise-induced arterial O2 desaturation was evaluated by intravenous infusion of sodium bicarbonate (Bic, 1 M; 200-350 ml) or an equal volume of saline (Sal; 1 M) at a constant infusion rate during a "2,000-m" maximal ergometer row in five male oarsmen. Blood...

Interaction of (n-3) and (n-6) fatty acids in desaturation and chain elongation of essential fatty acids in cultured glioma cells

International Nuclear Information System (INIS)

Cook, H.W.; Spence, M.W.

1987-01-01

Recent research in various biological systems has revived interest in interactions between the (n-6) and (n-3) essential fatty acids. We have utilized cultured glioma cells to show that linolenic acid, 18:3(n-3), is rapidly desaturated and chain elongated; 20:5(n-3) is the major product and accumulates almost exclusively in phospholipids. We examined effects of various (n-6), (n-3), (n-9) and (n-7) fatty acids at 40 microM concentration on desaturation and chain elongation processes using [1- 14 C]18:3(n-3) as substrate. In general, monoenoic fatty acids were without effect. The (n-6) fatty acids (18:2, 18:3, 20:3, 20:4 and 22:4) had little effect on total product formed. There was a shift of labeled product to triacylglycerol, and in phospholipids, slightly enhanced conversion of 20:5 to 22:5 was evident. In contrast, 22:6(n-3) was inhibitory, whereas 20:3(n-3) and 20:5(n-3) had much less effect. At concentrations less than 75 microM, all acids were inhibitory. Most products were esterified to phosphatidylcholine, but phosphatidylethanolamine also contained a major portion of 20:5 and 22:5. We provide a condensed overview of how the (n-6) and (n-3) fatty acids interact to modify relative rates of desaturation and chain elongation, depending on the essential fatty acid precursor. Thus, the balance between these dietary acids can markedly influence enzymes providing crucial membrane components and substrates for biologically active oxygenated derivatives

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

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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.

Drug metabolism by cytochrome p450 enzymes: what distinguishes the pathways leading to substrate hydroxylation over desaturation?

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Ji, Li; Faponle, Abayomi S; Quesne, Matthew G; Sainna, Mala A; Zhang, Jing; Franke, Alicja; Kumar, Devesh; van Eldik, Rudi; Liu, Weiping; de Visser, Sam P

2015-06-15

Cytochrome P450 enzymes are highly versatile biological catalysts in our body that react with a broad range of substrates. Key functions in the liver include the metabolism of drugs and xenobiotics. One particular metabolic pathway that is poorly understood relates to the P450 activation of aliphatic groups leading to either hydroxylation or desaturation pathways. A DFT and QM/MM study has been carried out on the factors that determine the regioselectivity of aliphatic hydroxylation over desaturation of compounds by P450 isozymes. The calculations establish multistate reactivity patterns, whereby the product distributions differ on each of the spin-state surfaces; hence spin-selective product formation was found. The electronic and thermochemical factors that determine the bifurcation pathways were analysed and a model that predicts the regioselectivity of aliphatic hydroxylation over desaturation pathways was established from valence bond and molecular orbital theories. Thus, the difference in energy of the OH versus the OC bond formed and the π-conjugation energy determines the degree of desaturation products. In addition, environmental effects of the substrate binding pocket that affect the regioselectivities were identified. These studies imply that bioengineering P450 isozymes for desaturation reactions will have to include modifications in the substrate binding pocket to restrict the hydroxylation rebound reaction. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influences of obstructive sleep apnea on blood pressure variability might not be limited only nocturnally in middle-aged hypertensive males.

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Shao, Liang; Heizhati, Mulalibieke; Yao, Xiaoguang; Wang, Yingchun; Abulikemu, Suofeiya; Zhang, Delian; Zhou, Ling; Hong, Jing; Li, Nanfang

2018-05-01

In this cross-sectional study, we analyzed the potential association between sleep measures and blood pressure variability. Ninety-three middle-aged hypertensive males, who underwent polysomnography and 24-h ambulatory blood pressure monitoring, were enrolled. Blood pressure variability was assessed by blood pressure standard deviation. Obstructive sleep apnea (apnea hypopnea index ≥ 15) was diagnosed in 52 (55.91%) patients. Mean body mass index and age were 27.77 ± 3.11 kg/m 2 and 44.05 ± 8.07 years, respectively. Hypertensive males with obstructive sleep apnea showed significantly higher 24-h, diurnal, and nocturnal diastolic blood pressure variability, compared to those without obstructive sleep apnea. While total cohort was further divided into two groups using the median of oxygen desaturation index, another indicator for severity of OSA, significant differences were also observed in 24-h, diurnal, and nocturnal diastolic blood pressure variability between two groups with higher and lower oxygen desaturation index. While subjects were also divided into two groups via the mean of sleep stage 1, hypertensive males with sleep stage 1 ≥ 8.1% showed significantly higher diurnal diastolic blood pressure variability than those with sleep stage 1 blood pressure variability; oxygen desaturation index of 3% with 24-h diastolic, diurnal, and nocturnal diastolic blood pressure; and sleep stage 1 was with 24-h and with diurnal diastolic blood pressure variability in all study subjects. Effects of obstructive sleep apnea on blood pressure variability may not be limited nocturnally.

Dessaturação noturna: preditores e influência no padrão do sono de pacientes portadores de doença pulmonar obstrutiva crônica com hipoxemia leve em vigília Nocturnal desaturation: predictors and the effect on sleep patterns in patients with chronic obstructive pulmonary disease and concomitant mild daytime hypoxemia

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Renata Claudia Zanchet

2006-06-01

predicting nocturnal desaturation, and to evaluate the influence of nocturnal desaturation on the sleep pattern of these patients. METHODS: Twenty-five patients were divided into two groups: those with nocturnal desaturation and those without. RESULTS: Comparing the first group (52% with the second, we found the following: age, 63 ± 5 years versus 63 ± 6 years; forced expiratory volume in the first second = 53 ± 31% versus 56 ± 19% predicted; ratio of forced expiratory volume in the first second to forced vital capacity, 49 ± 14% versus 52 ± 10%; arterial oxygen tension, 68 ± 8 mmHg versus 72 ± 68 mmHg; and arterial oxygen saturation, 93 ± 2% versus 94 ± 1%. Patients in the nocturnal desaturation group presented lower daytime arterial oxygen saturation and nocturnal arterial oxygen saturation by pulse oximetry. There was no difference between the two groups in terms of the sleep patterns observed. The ratio of forced expiratory volume in the first second to forced vital capacity was found to correlate with forced vital capacity, daytime arterial oxygen tension and daytime arterial oxygen saturation. In addition, arterial oxygen saturation by pulse oximetry during exercise was found to correlate with nocturnal arterial oxygen saturation by pulse oximetry. However, only daytime arterial oxygen saturation was predictive of nocturnal desaturation. CONCLUSION: The only variable capable of predicting nocturnal desaturation was daytime arterial oxygen saturation. Nocturnal desaturation did not influence the sleep patterns of patients with chronic obstructive pulmonary disease accompanied by mild daytime hypoxemia.

Optimal oxygen saturation in premature infants

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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.

Use of high-flow nasal cannula in obese patients receiving colonoscopy under intravenous propofol sedation: A case series

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Chi Chan Lee

Full Text Available Intravenous sedation during colonoscopy has become the standard practice in the United States given its higher patient satisfaction and procedural quality. This practice is not free of side effects as a significant proportion of patients undergoing this procedure tend to have respiratory depression and desaturation events. Obesity, as it relates to higher levels of body mass index (BMI has a positive correlation with the incidence of hypoxemia. During colonoscopy High flow nasal cannula (HFNC may potentially improve oxygen performance in patients receiving colonoscopy under intravenous sedation. Here we present 3 cases of patients undergoing adjunctive oxygen therapy with HFNC during colonoscopy with intravenous sedation. We found patients to have lower number of desaturation events and were satisfied with their experience. Keywords: High BMI (body mass index, HFNC (high-flow nasal cannula, Colonoscopy, Intravenous sedation, Obesity

Systematic review of near-infrared spectroscopy determined cerebral oxygenation during non-cardiac surgery

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Henning Bay Nielsen

2014-03-01

Full Text Available Near-infrared spectroscopy (NIRS is used to monitor regional cerebral oxygenation (rScO2 during cardiac surgery but is less established during non-cardiac surgery. This systematic review aimed i to determine the non-cardiac surgical procedures that provoke a reduction in rScO2 and ii to evaluate whether an intraoperative reduction in rScO2 influences postoperative outcome. The PubMed and Embase database were searched from inception until April 30, 2013 and inclusion criteria were intraoperative NIRS determined rScO2 in adult patients undergoing non-cardiac surgery. The type of surgery and number of patients included were recorded. There was included 113 articles and evidence suggests that rScO2 is reduced during thoracic surgery involving single lung ventilation, major abdominal surgery, hip surgery, and laparascopic surgery with the patient placed in anti-Tredelenburg’s position. Shoulder arthroscopy in the beach chair and carotid endarterectomy with clamped internal carotid artery also cause pronounced cerebral desaturation. A >20% reduction in rScO2 coincides with indices of regional and global cerebral ischemia during carotid endarterectomy. Following thoracic surgery, major orthopedic and abdominal surgery the occurrence of postoperative cognitive dysfunction might be related to intraoperative cerebral desaturation. In conclusion, certain non-cardiac surgical procedures is associated with an increased risk for the occurrence of regional cerebral oxygenation. Evidence for an association between cerebral desaturation and postoperative outcome parameters other than cognitive dysfunction needs to be established.

Examination of Pulse Oximetry Tracings to Detect Obstructive Sleep Apnea in Patients with Advanced Chronic Obstructive Pulmonary Disease

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Adrienne S Scott

2014-01-01

Full Text Available Nocturnal hypoxemia and obstructive sleep apnea (OSA are common comorbidities in patients with chronic obstructive pulmonary disease (COPD. The authors sought to develop a strategy to interpret nocturnal pulse oximetry and assess its capacity for detection of OSA in patients with stage 3 to stage 4 COPD. A review of consecutive patients with COPD who were clinically prescribed oximetry and polysomnography was conducted. OSA was diagnosed if the polysomnographic apnea-hypopnea index was >15 events/h. Comprehensive criteria were developed for interpretation of pulse oximetry tracings through iterative validation and interscorer concordance of ≥80%. Criteria consisted of visually identified desaturation ‘events’ (sustained desaturation ≥4%, 1 h time scale, ‘patterns’ (≥3 similar desaturation/saturation cycles, 15 min time scale and the automated oxygen desaturation index. The area under the curve (AUC, sensitivity, specificity and accuracy were calculated. Of 59 patients (27 male, 31 had OSA (53%. The mean forced expiratory volume in 1 s was 46% of predicted (range 21% to 74% of predicted and 52% of patients were on long-term oxygen therapy. Among 59 patients, 35 were correctly identified as having OSA or not having OSA, corresponding to an accuracy of 59%, with a sensitivity and specificity of 59% and 60%, respectively. The AUC was 0.57 (95% CI 0.55 to 0.59. Using software-computed desaturation events (hypoxemia ≥4% for ≥10 s indexed at ≥15 events/h of sleep as diagnostic criteria, sensitivity was 60%, specificity was 63% and the AUC was 0.64 (95%CI 0.62 to 0.66. No single criterion demonstrated important diagnostic utility. Pulse oximetry tracing interpretation had a modest diagnostic value in identifying OSA in patients with moderate to severe COPD.

Oxygen saturation index and severity of hypoxic respiratory failure.

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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

Ventilation test at Mont Terri. Geoelectric monitoring of the opalinus clay desaturation. Phase 2

International Nuclear Information System (INIS)

Wieczorek, Klaus; Zhang, Chun-Liang; Rothfuchs, Tilmann

2008-04-01

Between December 2001 and May 2004, a ventilation experiment (VE) was performed in the Mont Terri Underground Research Laboratory (URL) and co-financed by the Commission of the European Communities. The objective was to investigate the desaturation of consolidated clay formations in consequence of the ventilation of underground openings of a repository in such a formation. The results of the geoelectric measurements performed in the second phase of the Mont Terri ventilation test can be summarized as follows: Geoelectric tomography has been found suitable for monitoring ventilation-induced saturation changes in the Opalinus clay. During ventilation with dry air a desaturation down to below 50% could be detected in both desaturation cycles. The desaturated zone extends less than 0.5 m into the rock around the microtunnel. During the second resaturation phase, ventilation with humid air led to quick resaturation at the tunnel surface, while resaturation of the rock mass took months. The still ongoing third resaturation phase seems to imply that resaturation of the rock mass may take years with no air circulation in the tunnel. The laboratory investigations on the Opalinus clay included the determination of water retention capacity, swelling pressure, free swelling/shrinking strains induced by moisture changes, and response of normal and large hollow clay samples to the ventilation of the central boreholes at different air humidity values. The Opalinus clay has a high water absorption capacity. The amount of water uptake in unconstraint conditions is much higher than the water content in the naturally confined state, indicating that the pore water in the natural clay rock is predominantly bound on clay minerals. The swelling pressure induced by wetting with vapour is very close to the major lithostatic stress at the sampling location. Water uptake from vapour causes a large free expansion of up to 12% over 8 months and even a breakdown along bedding planes. Release of

Novel Desaturation Cell to Quantify Gushing Intensity: A Preliminary Study on Model Solutions

Czech Academy of Sciences Publication Activity Database

Novák, Pavel; Poštulková, Michaela; Růžička, Marek; Brányik, T.

2015-01-01

Roč. 73, č. 2 (2015), s. 185-189 ISSN 0361-0470 R&D Projects: GA MŠk(CZ) LD13018 Institutional support: RVO:67985858 Keywords : gushing * desaturation cell * gushing matrix Subject RIV: EI - Biotechnology ; Bionics Impact factor: 0.492, year: 2015

Prognostic value of efficiently correcting nocturnal desaturations after one month of non-invasive ventilation in amyotrophic lateral sclerosis: a retrospective monocentre observational cohort study.

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Gonzalez-Bermejo, Jésus; Morelot-Panzini, Capucine; Arnol, Nathalie; Meininger, Vincent; Kraoua, Salah; Salachas, François; Similowski, Thomas

2013-09-01

Abstract NIV adherence ('quantity' of ventilation) has a prognostic impact in amyotrophic lateral sclerosis (ALS). We hypothesized that NIV effectiveness ('quality') could also have a similar impact. NIV effectiveness was evaluated in 82 patients within the first month (M1) and every three months (symptoms, arterial blood bases, and nocturnal pulsed oxygen saturation - SpO2). Kaplan-Meier survival and risk factors for mortality one year after NIV initiation were evaluated. Forty patients were considered 'correctly ventilated' at M1 (Group 1, less than 5% of nocturnal oximetry time with an SpO2NIV effectiveness to correct nocturnal desaturations is an independent prognostic factor.

Dapsone Induced Methaemoglobinemia: Early Intraoperative Detection by Pulse Oximeter Desaturation

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Mahmood Rafiq

2008-01-01

Case signifies the importance of knowledge of any preoperative drug intake and its anaesthetic implications. Also patients on dapsone therapy especially children should be monitored for methaemoglobin levels. Since children with immune thrombocy-topenic purpura are being treated with dapsone these days and many of these patients would be planned for splenectomy, monitoring of preoperative methaemoglobin levels and methaemoglobinemia as a cause of intraoperative pulse oximeter desaturation should be kept in mind.

A graphical method for comparing nocturnal oxygen saturation profiles in individuals and populations: Application to healthy infants and preterm neonates.

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Terrill, Philip I; Dakin, Carolyn; Edwards, Bradley A; Wilson, Stephen J; MacLean, Joanna E

2018-05-01

Pulse-oximetry (SpO 2 ) allows the identification of important clinical physiology. However, summary statistics such as mean values and desaturation incidence do not capture the complexity of the information contained within continuous recordings. The aim of this study was to develop an objective method to quantify important SpO 2 characteristics; and assess its utility in healthy infant and preterm neonate cohorts. An algorithm was developed to calculate the desaturation incidence, depth, and duration. These variables are presented using three plots: SpO 2 cumulative-frequency relationship; desaturation-depth versus incidence; desaturation-duration versus incidence. This method was applied to two populations who underwent nocturnal pulse-oximetry: (1) thirty-four healthy term infants studied at 2-weeks, 3, 6, 12, and 24-months of age and (2) thirty-seven neonates born <26 weeks and studied at discharge from NICU (37-44 weeks post-conceptual age). The maturation in healthy infants was characterized by reduced desaturation index (27.2/h vs 3.3/h at 2-weeks and 24-months, P < 0.01), and increased percentage of desaturation events ≥6-s in duration (27.8% vs 43.2% at 2-weeks and 3-months, P < 0.01). Compared with term-infants, preterm infants had a greater desaturation incidence (54.8/h vs 27.2/h, P < 0.01), and these desaturations were deeper (52.9% vs 37.6% were ≥6% below baseline, P < 0.01). The incidence of longer desaturations (≥14-s) in preterm infants was correlated with healthcare utilization over the first 24-months (r = 0.63, P < 0.01). This tool allows the objective comparison of extended oximetry recordings between groups and for individuals; and serves as a basis for the development of reference ranges for populations. © 2018 Wiley Periodicals, Inc.

Limited oxygen index levels of impregnated Scots pine wood

International Nuclear Information System (INIS)

Tomak, Eylem Dizman; Cavdar, Ayfer Donmez

2013-01-01

Highlights: • Scots pine samples were treated with 4 wood preservatives with various concentrations. • Limited oxygen index level was evaluated both for leached and un-leached samples. • All treatments improved fire retardance of samples despite some chemicals leached out. • Samples treated with fireproof agent showed the best results. • LOI of samples treated with boron powder and silicon oil was not changed by leaching. - Abstract: In this study, effect of various concentrations of boron powder, mixture of boric acid and borax, fireproof agent based on liquid blend of limestone, and silicon oil on limited oxygen index levels (LOI) of S. pine wood was investigated. Wood samples were first vacuum treated with the preservatives, and then were subjected to leaching procedure. Samples treated with fireproof agent showed the best results for improving the fire retardancy of wood, furthermore, samples treated with 25%, 50% and 100% of the solution did not burn. Leaching did not considerably change the LOI of wood samples treated with boron powder and silicon oil; however, LOI levels of samples treated with the mixture of boric acid and borax and fireproof agent were affected by leaching procedure probably arising those preservatives did not chemically bond to main wood components. All treatments improved fire retardancy of samples despite some amount of preservatives leached out from wood

Limited oxygen index levels of impregnated Scots pine wood

Energy Technology Data Exchange (ETDEWEB)

Tomak, Eylem Dizman, E-mail: eylemdizman@yahoo.com [Forest Industry Engineering Department, Faculty of Forestry, Bursa Technical University, 16200 Bursa (Turkey); Cavdar, Ayfer Donmez [Interior Architecture Department, Faculty of Architecture, Karadeniz Technical University, 61080 Trabzon (Turkey)

2013-12-10

Highlights: • Scots pine samples were treated with 4 wood preservatives with various concentrations. • Limited oxygen index level was evaluated both for leached and un-leached samples. • All treatments improved fire retardance of samples despite some chemicals leached out. • Samples treated with fireproof agent showed the best results. • LOI of samples treated with boron powder and silicon oil was not changed by leaching. - Abstract: In this study, effect of various concentrations of boron powder, mixture of boric acid and borax, fireproof agent based on liquid blend of limestone, and silicon oil on limited oxygen index levels (LOI) of S. pine wood was investigated. Wood samples were first vacuum treated with the preservatives, and then were subjected to leaching procedure. Samples treated with fireproof agent showed the best results for improving the fire retardancy of wood, furthermore, samples treated with 25%, 50% and 100% of the solution did not burn. Leaching did not considerably change the LOI of wood samples treated with boron powder and silicon oil; however, LOI levels of samples treated with the mixture of boric acid and borax and fireproof agent were affected by leaching procedure probably arising those preservatives did not chemically bond to main wood components. All treatments improved fire retardancy of samples despite some amount of preservatives leached out from wood.

Under general anesthesia arginine vasopressin prevents hypotension but impairs cerebral oxygenation during arthroscopic shoulder surgery in the beach chair position.

Science.gov (United States)

Cho, Soo Y; Kim, Seok J; Jeong, Cheol W; Jeong, Chang Y; Chung, Sung S; Lee, JongUn; Yoo, Kyung Y

2013-12-01

Patients undergoing surgery in the beach chair position (BCP) are at a risk of cerebral ischemia. We evaluated the effect of arginine vasopressin (AVP) on hemodynamics and cerebral oxygenation during surgery in the BCP. Thirty patients undergoing shoulder surgery in BCP under propofol-remifentanil anesthesia were randomly allocated either to receive IV AVP 0.07 U/kg (AVP group, N = 15) or an equal volume of saline (control group, N = 15) 2 minutes before taking BCP. Mean arterial blood pressure (MAP), heart rate (HR), jugular venous bulb oxygen saturation (SjvO2), and regional cerebral tissue oxygen saturation (SctO2) were measured after induction of anesthesia and before (presitting in supine position) and after patients took BCP. AVP itself given before the positioning increased MAP and decreased SjvO2 and SctO2 (P 20% SctO2 decrease from presitting value) (80% vs 13%; P = 0.0003) was higher in the AVP group. The incidence of jugular desaturation (SjvO2 shoulder surgery under general anesthesia. However, it was associated with regional cerebral but not jugular venous oxygen desaturation on upright positioning.

Crosstalk between nitrite, myoglobin and reactive oxygen species to regulate vasodilation under hypoxia.

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Matthias Totzeck

Full Text Available The systemic response to decreasing oxygen levels is hypoxic vasodilation. While this mechanism has been known for more than a century, the underlying cellular events have remained incompletely understood. Nitrite signaling is critically involved in vessel relaxation under hypoxia. This can be attributed to the presence of myoglobin in the vessel wall together with other potential nitrite reductases, which generate nitric oxide, one of the most potent vasodilatory signaling molecules. Questions remain relating to the precise concentration of nitrite and the exact dose-response relations between nitrite and myoglobin under hypoxia. It is furthermore unclear whether regulatory mechanisms exist which balance this interaction. Nitrite tissue levels were similar across all species investigated. We then investigated the exact fractional myoglobin desaturation in an ex vivo approach when gassing with 1% oxygen. Within a short time frame myoglobin desaturated to 58±12%. Given that myoglobin significantly contributes to nitrite reduction under hypoxia, dose-response experiments using physiological to pharmacological nitrite concentrations were conducted. Along all concentrations, abrogation of myoglobin in mice impaired vasodilation. As reactive oxygen species may counteract the vasodilatory response, we used superoxide dismutase and its mimic tempol as well as catalase and ebselen to reduce the levels of reactive oxygen species during hypoxic vasodilation. Incubation of tempol in conjunction with catalase alone and catalase/ebselen increased the vasodilatory response to nitrite. Our study shows that modest hypoxia leads to a significant nitrite-dependent vessel relaxation. This requires the presence of vascular myoglobin for both physiological and pharmacological nitrite levels. Reactive oxygen species, in turn, modulate this vasodilation response.

Contribution of two ζ-carotene desaturases to the poly-cis desaturation pathway in the cyanobacterium Nostoc PCC 7120.

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Breitenbach, Jürgen; Bruns, Marius; Sandmann, Gerhard

2013-07-01

The presence of two completely unrelated ζ-carotene desaturases CrtQa and CrtQb in some Nostoc strains is unique. CrtQb is the ζ-carotene desaturase, which was acquired by almost all cyanobacteria. The additional CrtQa can be regarded as an evolutionary relict of the CrtI desaturase present in non-photosynthetic bacteria. By reconstruction of the carotene desaturation pathway, we showed that both enzymes from Nostoc PCC 7120 were active. However, they differed in their preferred utilization of ζ-carotene Z isomers. CrtQa converted ζ-carotene isomers that were poorly metabolized by CrtQb. In this respect, CrtQa complemented the reactions of CrtQb, which is an advantage avoiding dead ends in the poly-cis desaturation pathway. In addition to ζ-carotene desaturation, CrtQa still possesses the Z to E isomerase function of the ancestral desaturase CrtI. Biochemical characterization showed that CrtQb is an enzyme with one molecule of tightly bound FAD and acts as a dehydrogenase transferring hydrogen to oxidized plastoquinone.

Oxygen and the evolution of metabolic pathways

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Jahnke, L. L.

1986-01-01

While a considerable amount of evidence has been accumulated about the history of oxygen on this planet, little is known about the relative amounts to which primitive cells might have been exposed. One clue may be found in the metabolic pathways of extant microorganisms. While eucaryotes are principally aerobic organisms, a number are capable of anaerobic growth by fermentation. One such eucaryotic microorganism, Saccharomyces cerevisiae, will grow in the complete absence of oxygen when supplemented with unsaturated fatty acid and sterol. Oxygen-requiring enzymes are involved in the synthesis of both of these compounds. Studies have demonstrated that the oxidative desaturation of palmitic acid and the conversion of squalene to sterols occur in the range of 10-(3) to 10(-2) PAL. Thus, if the oxygen requirements of these enzymatic processes are an indication, eucaryotes might be more primitive than anticipated from the microfossil record. Results of studies on the oxygen requirements for sterol and unsaturated fatty acid synthesis in a more primitive procaryotic system are also discussed.

ESTIMATION OF INDUSTRIAL WASTE SAFETY BY THE “CHEMICAL OXYGEN DEMAND” INDEX

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A. S. Kayshev

2015-01-01

Full Text Available One of the indices of industrial waste safety including distillers grains is chemical oxygen demand (COD, and its value (53591÷64184 mg O/dm3 shows that it can be considered as unsustainable waste. This high value of COD is conditioned by the absence of toxins in distillers grains, and by concentration of biologically active substances after which isolation the distillers grains index lowers by 74%. This allows considering the distillers grains as environmentally safe. The results received evidence the necessity for consideration of COD index only as an index of oxidized substances, but not the criteria of waste pollution.

Cerebral oxygen delivery is reduced in newborns with congenital heart disease.

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Lim, Jessie Mei; Kingdom, Theodore; Saini, Brahmdeep; Chau, Vann; Post, Martin; Blaser, Susan; Macgowan, Christopher; Miller, Steven P; Seed, Mike

2016-10-01

To investigate preoperative cerebral hemodynamics in newborns with congenital heart disease. We hypothesized that cerebral blood flow and oxygen delivery would be decreased in newborns with congenital heart disease compared with controls. Using a "feed-and-sleep" approach to performing neonatal magnetic resonance imaging, we measured cerebral blood flow by using a slice prescription perpendicular to the right and left internal carotid arteries and basilar artery at the level of the clivus. We calculated brain volume by segmenting a 3-dimensional steady-state free procession acquisition of the whole brain, allowing quantification of cerebral blood flow indexed to brain volume. Cerebral oxygen delivery was calculated as the product of cerebral blood flow and preductal systemic arterial oxygen content obtained via a combination of conventional pulse oximetry and laboratory analysis of venous blood samples for hemoglobin concentration. A complete set of measurements were obtained in 32 newborns with heart disease and 31 controls. There was no difference in gestational age between the heart disease and control groups. There was no difference in cerebral blood flow compared with controls (103.5 ± 34.0 vs 119.7 ± 40.4 mL/min), whereas cerebral oxygen delivery was significantly lower in the congenital heart disease subjects (1881 ± 625.7 vs 2712 ± 915.7 mLO2/min). Ten newborns with congenital heart disease had diffuse excessive high signal intensity in their white matter and 2 had white matter injury whereas another 5 had both. Newborns with unrepaired cyanotic congenital heart disease have decreased cerebral oxygen delivery due to arterial desaturation. If brain growth and development are adversely affected through oxygen conformance, our findings could have clinical implications in terms of timing of surgical repair. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Adsorption of oxygen on low-index surfaces of the TiAl{sub 3} alloy

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Latyshev, A. M.; Bakulin, A. V.; Kulkova, S. E., E-mail: kulkova@ms.tsc.ru [National Research Tomsk State University (Russian Federation); Hu, Q. M.; Yang, R. [Chinese Academy of Sciences, Shenyang National Laboratory for Materials Science, Institute of Metal Research (China)

2016-12-15

Method of the projector augmented waves in the plane-wave basis within the generalized-gradient approximation for the exchange-correlation functional has been used to study oxygen adsorption on (001), (100), and (110) low-index surfaces of the TiAl{sub 3} alloy. It has been established that the sites that are most energetically preferred for the adsorption of oxygen are hollow (H) positions on the (001) surface and bridge (B) positions on the (110) and (100) surfaces. Structural and electronic factors that define their energy preference have been discussed. Changes in the atomic and electronic structure of subsurface layers that occur as the oxygen concentration increases to three monolayers have been analyzed. It has been shown that the formation of chemical bonds of oxygen with both components of the alloy leads to the appearance of states that are split-off from the bottoms of their valence bands, which is accompanied by the formation of a forbidden gap at the Fermi level and by a weakening of the Ti–Al metallic bonds in the alloy. On the Al-terminated (001) and (110) surfaces, the oxidation of aluminum dominates over that of titanium. On the whole, the binding energy of oxygen on the low-index surfaces with a mixed termination is higher than that at the aluminum-terminated surface. The calculation of the diffusion of oxygen in the TiAl{sub 3} alloy has shown that the lowest barriers correspond to the diffusion between tetrahedral positions in the (001) plane; the diffusion of oxygen in the [001] direction occurs through octahedral and tetrahedral positions. An increase in the concentration of aluminum in the alloy favors a reduction in the height of the energy barriers as compared to the corresponding barriers in the γ-TiAl alloy.

Polysomnography for the management of oxygen supplementation therapy in infants with chronic lung disease of prematurity.

Science.gov (United States)

Kulkarni, Gaurav; de Waal, Koert; Grahame, Sally; Collison, Adam; Roddick, Laurence; Hilton, Jodi; Gulliver, Tanya; Whitehead, Bruce; Mattes, Joerg

2018-04-25

Some infants with bronchopulmonary dysplasia (BPD) may require oxygen supplementation at home but a role for overnight polysomnography (PSG) in the management of home oxygen therapy has been rarely described. Forty-one infants with BPD born at less than 30 weeks gestational age were discharged with continuous home oxygen supplementation therapy between 2010 and 2013. PSG data were recorded on oxygen supplementation versus room air at median post conceptual age of 2 months (range 1-5.5 months) (first PSG after discharge to home). Those infants who continued oxygen supplementation therapy at home had at least one more PSG before oxygen therapy was discontinued (last PSG). We also collected PSG data in 10 healthy term infants (median age 3.5 months; range 2-4 months). In infants with BPD in room air, increased numbers of central apnoeas, hypopnoeas and SaO 2 desaturations were the predominant PSG features with a median apnoea-hypopnoea index (AHI) of 16.8 events per hour (range 0-155). On oxygen supplementation therapy, median AHI dramatically improved (2.2, range 0-22; p < 0.001) and was not different from control infants (2.0, range 0-3.9; p = 0.31). AHI on room air at the last PSG when home oxygen was ceased was 4.1 per hour (range 0-13.8) slightly higher than in healthy infants. Central sleep disordered breathing in infants with BPD dramatically normalises with low flow nasal cannula home oxygen therapy and improves with age. Mild central sleep disordered breathing remains detectable, although much improved, when compared to healthy infants at the time when the decision to cease home oxygen therapy was made by the physician.

Relationship between interatrial communication, ductus arteriosus, and pulmonary flow patterns in fetuses with transposition of the great arteries: prediction of neonatal desaturation.

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Vaujois, Laurence; Boucoiran, Isabelle; Preuss, Christophe; Brassard, Myriam; Houde, Christine; Fouron, Jean C; Raboisson, Marie-Josée

2017-09-01

The relationship between interatrial communication, ductus arteriosus, and pulmonary flow in transposition of the great arteries and intact ventricular septum may help predict postnatal desaturation. Echocardiographic data of 45 fetuses with transposition of the great arteries and intact ventricular septum and 50 age-matched controls were retrospectively reviewed. Interatrial communication, left and right ventricular output, flow in the ductus arteriosus, as well as effective pulmonary flow were measured. Patients were divided into two groups on the basis of postnatal saturations: group 1 had saturations ⩽50% and group 2 >50%. Of 45 fetuses, 13 (26.7%) were classified into group 1. Compared with fetuses in group 2, they had a smaller interatrial communication (2.9 versus 4.0 mm, p=0.004) and more retrograde diastolic flow in the ductus arteriosus (92 versus 23%, p=0.002). Both groups showed a significant decrease in ductal flow compared with controls. Patients in group 2 had a higher effective pulmonary flow compared with controls. There was a mild correlation between left ventricular output and size of the interatrial communication (Spearman's rank correlation 0.44). A retrograde diastolic flow is present in most of the fetuses with postnatal desaturation. Fetuses with transposition of the great arteries have a lower flow through the ductus arteriosus compared with controls. Fetuses without restrictive foramen ovale have higher effective pulmonary flow. Peripheral pulmonary vasodilatation due to higher oxygen saturation in pulmonary arteries in the case of transposition of the great arteries could be one possible cause.

Saturation and desaturation of fatty acids in digestion channel and its wall in ruminants

International Nuclear Information System (INIS)

Martyushov, V.M.; Aliev, A.A.

1987-01-01

It is stated that ration physical structure has considerable effect on hydrogenation of unsaturated acids in ruminants rumens. Saturation of unsaturated acids decreases with the ration of crushed granulated feeds. The gastrointestinal stenosis possessing desaturation activity dehydrogenizes octadecanoic acid formed by microorganisms in pregasters and provides sheep (ruminants) organism with unsaturated acids

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

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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

Screening for Sleep Apnoea in Mild Cognitive Impairment: The Utility of the Multivariable Apnoea Prediction Index

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Georgina Wilson

2014-01-01

Full Text Available Purpose. Mild cognitive impairment (MCI is considered an “at risk” state for dementia and efforts are needed to target modifiable risk factors, of which Obstructive sleep apnoea (OSA is one. This study aims to evaluate the predictive utility of the multivariate apnoea prediction index (MAPI, a patient self-report survey, to assess OSA in MCI. Methods. Thirty-seven participants with MCI and 37 age-matched controls completed the MAPI and underwent polysomnography (PSG. Correlations were used to compare the MAPI and PSG measures including oxygen desaturation index and apnoea-hypopnoea index (AHI. Receiver-operating characteristics (ROC curve analyses were performed using various cut-off scores for apnoea severity. Results. In controls, there was a significant moderate correlation between higher MAPI scores and more severe apnoea (AHI: r=0.47, P=0.017. However, this relationship was not significant in the MCI sample. ROC curve analysis indicated much lower area under the curve (AUC in the MCI sample compared to the controls across all AHI severity cut-off scores. Conclusions. In older people, the MAPI moderately correlates with AHI severity but only in those who are cognitively intact. Development of further screening tools is required in order to accurately screen for OSA in MCI.

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

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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.

Association of apneic oxygenation with decreased desaturation rates during rapid sequence intubation by a Chinese emergency medicine service.

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Mao, Yong; Qin, Zong-He

2015-01-01

Rapid and safe airway management has always been of paramount importance in successful management of critically ill and injured patients in the emergency department. The achievement rate of emergency medicine inhabitants in airway management improved enhanced essentially subsequent to finishing anaesthesiology turn. There was a slightly higher rate of quick sequence intubation in the postapneic oxygenation groups (preapneic oxygenation 6.4%; postapneic oxygenation 9.1%). The majority of patients intubated in both groups were men (preapneic oxygenation 72.3%; postapneic oxygenation 63.5%). A higher percentage of patients in the preapneic oxygenation group had a Cormack-Lehane grade III or worse view (23.2% versus 11.8%). Anaesthesiology turns should be considered as an essential component of emergency medicine training programs. A collateral curriculum of this nature should also focus on the acquisition of skills in airway management.

Automated oxygen titration and weaning with FreeO2 in patients with acute exacerbation of COPD: a pilot randomized trial

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Lellouche F

2016-08-01

Full Text Available François Lellouche,1 Pierre-Alexandre Bouchard,1 Maude Roberge,1 Serge Simard,1,2 Erwan L’Her,1,3 François Maltais,1 Yves Lacasse1 1Research Centre, 2Biostatistics Department, Quebec Heart and Lung Institute, Laval University, 3Emergency Medicine, Hôtel-Dieu de Lévis, Laval University, Quebec City, QC, Canada Introduction: We developed a device (FreeO2 that automatically adjusts the oxygen flow rates based on patients’ needs, in order to limit hyperoxia and hypoxemia and to automatically wean them from oxygen. Objective: The aim of this study was to evaluate the feasibility of using FreeO2 in patients hospitalized in the respiratory ward for an acute exacerbation of COPD. Methods: We conducted a randomized controlled trial comparing FreeO2 vs manual oxygen titration in the respiratory ward of a university hospital. We measured the perception of appropriateness of oxygen titration and monitoring in both groups by nurses and attending physicians using a Likert scale. We evaluated the time in the target range of oxygen saturation (SpO2 as defined for each patient by the attending physician, the time with severe desaturation (SpO2 <85%, and the time with hyperoxia (SpO2 >5% above the target. We also recorded length of stay, intensive care unit admissions, and readmission rate. Fifty patients were randomized (25 patients in both groups; mean age: 72±8 years; mean forced expiratory volume in 1 second: 1.00±0.49 L; and mean initial O2 flow 2.0±1.0 L/min. Results: Nurses and attending physicians felt that oxygen titration and monitoring were equally appropriate with both O2 administration systems. The percentage of time within the SpO2 target was significantly higher with FreeO2, and the time with severe desaturation and hyperoxia was significantly reduced with FreeO2. Time from study inclusion to hospital discharge was 5.8±4.4 days with FreeO2 and 8.4±6.0 days with usual oxygen administration (P=0.051. Conclusion: FreeO2 was deemed as an

Ambulatory positional obstructive sleep apnea syndrome

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Fernando Di-Tullio

Full Text Available Objective: To establish the prevalence of positional (PP OSA patients using self-administered home-based respiratory polygraphy (RP. Materials and Methods: 52 month retrospective study based on RP records. Results: 200 PR records: 70.5% men 29.5% women. 76% were diagnosed with OSA and 54.6% with PP OSA. There were no significant differences in Epworth Sleepiness Scale, apnea hypopnea index and oxygen desaturation index. PP OSA patients were younger, had a lower BMI (30.3±0.9 vs. 35.3±1.2 (p<0.0001, and the time they spent with oxygen saturation <90% (T<90 was lower (8.8 vs. 28.7±6.7, p=0.0038. The PP OSA group spent 43% of total recording time in the supine position. Conclusions: The prevalence of PP OSA patients studied with RP is similar to the one described by sleep laboratories. They have lower BMI, present mostly mild OSA with less desaturation, and are less likely to receive CPAP therapy.

Impact of a Standard Rodent Chow Diet on Tissue n-6 Fatty Acids, Δ9-Desaturation Index, and Plasmalogen Mass in Rats Fed for One Year.

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Pédrono, F; Boulier-Monthéan, N; Catheline, D; Legrand, P

2015-11-01

Although many studies focus on senescence mechanisms, few habitually consider age as a biological parameter. Considering the effect of interactions between food and age on metabolism, here we depict the lipid framework of 12 tissues isolated from Sprague-Dawley rats fed standard rodent chow over 1 year, an age below which animals are commonly studied. The aim is to define relevant markers of lipid metabolism influenced by age in performing a fatty acid (FA) and dimethylacetal profile from total lipids. First, our results confirm impregnation of adipose and muscular tissues with medium-chain FA derived from maternal milk during early infancy. Secondly, when animals were switched to standard croquettes, tissues were remarkably enriched in n-6 FA and especially 18:2n-6. This impregnation over time was coupled with a decrease of the desaturation index and correlated with lower activities of hepatic Δ5- and Δ6-desaturases. In parallel, we emphasize the singular status of testis, where 22:5n-6, 24:4n-6, and 24:5n-6 were exceptionally accumulated with growth. Thirdly, 18:1n-7, usually found as a discrete FA, greatly accrued over the course of time, mostly in liver and coupled with Δ9-desaturase expression. Fourthly, skeletal muscle was characterized by a surprising enrichment of 22:6n-3 in adults, which tended to decline in older rats. Finally, plasmalogen-derived dimethylacetals were specifically abundant in brain, erythrocytes, lung, and heart. Most notably, a shift in the fatty aldehyde moiety was observed, especially in brain and erythrocytes, implying that red blood cell analysis could be a good indicator of brain plasmalogens.

Physical Activity and Exertional Desaturation Are Associated with Mortality in Idiopathic Pulmonary Fibrosis

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Baruch Vainshelboim

2016-08-01

Full Text Available Idiopathic pulmonary fibrosis (IPF is a chronic lung disease that manifests in hypoxemia, inactivity, and poor prognosis. This study aimed to assess the prognostic role of physical activity (PA and exertional desaturation (ED with mortality in IPF. At baseline, 34 IPF patients (68 (50–81 years were interviewed using the International Physical Activity Questionnaire (IPAQ, and SpO2 was assessed pre to post 6-min walking test (∆SpO2. Patients were prospectively followed up for 40 months. Receiver operating characteristics curve analysis determined cut-off points associated with mortality, and Cox proportional hazard ratio (HR were conducted. Thresholds for increased mortality risk in IPF patients were determined as IPAQ ≤ 417 metabolic equivalent task (METS-min/week, p = 0.004 (HR; 9.7, CI 95% (1.3–71.9, p = 0.027, and ∆SpO2 ≥ 10%, p = 0.002, (HR; 23.3, CI 95% (1.5–365, p = 0.025. This study demonstrated a significant association of PA and ED with mortality in IPF patients. The findings emphasize the clinical importance of PA and ED assessments to aid in IPF risk stratification, prognosis prediction, and in providing early appropriate treatments, such as pulmonary rehabilitation, PA consultation, oxygen supplementation, and lung transplantation referral. These results underscore that even low levels of PA corresponding to 100–105 min/week were associated with a reduced mortality risk and better survival in IPF.

Cytochrome P-450-catalyzed desaturation of valproic acid in vitro. Species differences, induction effects, and mechanistic studies

International Nuclear Information System (INIS)

Rettie, A.E.; Boberg, M.; Rettenmeier, A.W.; Baillie, T.A.

1988-01-01

The cytochrome P-450-mediated desaturation of valproic acid (VPA) to its hepatotoxic metabolite, 2-n-propyl-4-pentenoic acid (4-ene-VPA), was examined in liver microsomes from rats, mice, rabbits and humans. The highest substrate turnover was found with microsomes from rabbits (44.2 +/- 2.7 pmol of product/nmol P-450/15 min), while lower activities were observed in preparations from human, mouse, and rat liver, in that order. Pretreatment of animals with phenobarbital led to enhanced rates of formation of 4-ene-VPA in vitro and yielded induction ratios for desaturation ranging from 2.5 to 8.4, depending upon the species. Comparative studies in the rat showed that phenobarbital is a more potent inducer of olefin formation than either phenytoin or carbamazepine. The mechanism of the desaturation reaction was studied by inter- and intramolecular deuterium isotope effect experiments, which demonstrated that removal of a hydrogen atom from the subterminal C-4 position of VPA is rate limiting in the formation of both 4-ene- and 4-hydroxy-VPA. Hydroxylation at the neighboring C-5 position, on the other hand, was highly sensitive to deuterium substitution at that site, but not to deuteration at C-4. Based on these findings, it is proposed that 4-ene- and 4-hydroxy-VPA are products of a common P-450-dependent metabolic pathway, in which a carbon-centered free radical at C-4 serves as the key intermediate. 5-Hydroxy-VPA, in contrast, derives from an independent hydroxylation reaction

Minimally invasive prediction of ScvO2 in high-risk surgery : The introduction of a model Index of Oxygenation

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de Grooth, Harm-Jan S.; Vos, Jaap Jan; Scheeren, Thomas; van Beest, Paul

2014-01-01

INTRODUCTION: The purpose of this study was to examine the trilateral relationship between cardiac index (CI), tissue oxygen saturation (StO2) and central venous oxygen saturation (ScvO2) and subsequently develop a model to predict ScvO2 on minimal invasive manner in patients undergoing major

Influence of obstructive sleep apnea on fatty liver disease: role of chronic intermittent hypoxia.

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Türkay, Cansel; Ozol, Duygu; Kasapoğlu, Benan; Kirbas, Ismail; Yıldırım, Zeki; Yiğitoğlu, Ramazan

2012-02-01

Currently the common pathogenetic mechanisms in nonalcoholic fatty liver disease (NAFLD) and obstructive sleep apnea (OSA) are gaining increased attention. The aim of this study is to find out the influence of chronic intermittent hypoxemia and OSA related parameters to the severity of NAFLD. We examined the liver functions tests and ultrasonographic data of liver as well as markers of OSA severity (apnea-hypopnea index [AHI], oxygen desaturation index, minimum oxygen saturation, percentage of time spent with S(pO(2)) hypoxia during sleep. The prevalence of NAFLD was higher in patients with severe OSA, suggesting a role for nocturnal hypoxemia in the pathogenesis of fatty liver disease.

Simulating obstructive sleep apnea patients' oxygenation characteristics into a mouse model of cyclical intermittent hypoxia.

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Lim, Diane C; Brady, Daniel C; Po, Pengse; Chuang, Li Pang; Marcondes, Laise; Kim, Emily Y; Keenan, Brendan T; Guo, Xiaofeng; Maislin, Greg; Galante, Raymond J; Pack, Allan I

2015-03-01

Mouse models of cyclical intermittent hypoxia (CIH) are used to study the consequences of both hypoxia and oxidative stress in obstructive sleep apnea (OSA). Whether or not a mouse model of CIH that simulates OSA patients' oxygenation characteristics would translate into improved patient care remains unanswered. First we identified oxygenation characteristics using the desaturation and resaturation time in 47 OSA subjects from the Molecular Signatures of Obstructive Sleep Apnea Cohort (MSOSA). We observe that a cycle of intermittent hypoxia is not sinusoidal; specifically, desaturation time increases in an almost linear relationship to the degree of hypoxia (nadir), whereas resaturation time is somewhat constant (∼15 s), irrespective of the nadir. Second, we modified the Hycon mouse model of CIH to accommodate a 15-s resaturation time. Using this modified CIH model, we explored whether a short resaturation schedule (15 s), which includes the characteristics of OSA patients, had a different effect on levels of oxidative stress (i.e., urinary 8,12-iso-iPF2α-VI levels) compared with sham and a long resaturation schedule (90 s), a schedule that is not uncommon in rodent models of CIH. Results suggest that shorter resaturation time may result in a higher level of 8,12-iso-iPF2α-VI compared with long resaturation or sham conditions. Therefore, simulating the rodent model of CIH to reflect this and other OSA patients' oxygenation characteristics may be worthy of consideration to better understand the effects of hypoxia, oxidative stress, and their interactions. Copyright © 2015 the American Physiological Society.

The role of polysomnography in tracheostomy decannulation of the paediatric patient.

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Lee, Jennifer; Soma, Marlene A; Teng, Arthur Y; Thambipillay, Ganesh; Waters, Karen A; Cheng, Alan T

2016-04-01

Tracheostomy decannulation in the paediatric patient is usually considered when there is resolution or significant improvement in the original indication for the tracheostomy. The child's cardiorespiratory function needs to be optimized and assessment of the readiness for decannulation is generally by endoscopic evaluation to confirm airway patency and vocal cord mobility. Functional airway assessment procedures include downsizing the tracheostomy, adding fenestration, speaking valves and capping the tracheostomy tube. Few objective measures have been demonstrated to accurately predict the likelihood of successful decannulation. This study aims to evaluate the usefulness of polysomnography (PSG) with a capped tracheostomy tube, as an adjunct to airway endoscopy and traditional decannulation procedures, to predict decannulation outcome. A retrospective review was conducted for patients who underwent "capped" PSG prior to a trial of tracheostomy decannulation at the Sydney Children's Hospitals Network. The charts were reviewed for clinical data and PSG results. 30 children with a total of 40 PSG reports were included in this study. There was a statistically significant difference in mean oxygen saturation, minimum oxygen saturation, total apnoea/hypopnoea index, desaturations >3%, and desaturations >3% index between those that had successful decannulation compared to failed decannulation. The measures with the greatest significance, and therefore, the best predictors of decannulation outcome were total apnoea/hypopnoea index (3.35events/h vs. 18.5events/h, p=0.004) and desaturation events (20.33 events vs. 192 events, p=0.001). PSG with a capped tracheostomy tube is a useful, objective tool to complement endoscopy and functional airway assessment in the consideration of decannulation in the paediatric population. Crown Copyright © 2016. Published by Elsevier Ireland Ltd. All rights reserved.

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

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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.

Numerical Modeling of Limiting Oxygen Index Apparatus for Film Type Fuels

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Amit Kumar

2012-12-01

Full Text Available A detailed three-dimensional numerical model is used to compute the flow pattern and the flame behavior of thin solid fuels in a rectangular column that resembles a standard Limiting Oxygen Index (LOI device. The model includes full Navier-Stokes equations for mixed buoyant-forced flow and finite rate combustion and pyrolysis reactions so that the sample LOI can be computed to study the effect of feeding flow rate, sample width and gravity levels. In addition to the above parameters, the sample location in the column and the column cross-sectional area are also investigated on their effect on the ambient air entrainment from the top.

A single mutation in the castor Δ9-18:0-desaturase changes reaction partitioning from desaturation to oxidase chemistry

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Guy, Jodie E.; Abreu, Isabel A.; Moche, Martin; Lindqvist, Ylva; Whittle, Edward; Shanklin, John

2006-01-01

Sequence analysis of the diiron cluster-containing soluble desaturases suggests they are unrelated to other diiron enzymes; however, structural alignment of the core four-helix bundle of desaturases to other diiron enzymes reveals a conserved iron binding motif with similar spacing in all enzymes of this structural class, implying a common evolutionary ancestry. Detailed structural comparison of the castor desaturase with that of a peroxidase, rubrerythrin, shows remarkable conservation of both identity and geometry of residues surrounding the diiron center, with the exception of residue 199. Position 199 is occupied by a threonine in the castor desaturase, but the equivalent position in rubrerythrin contains a glutamic acid. We previously hypothesized that a carboxylate in this location facilitates oxidase chemistry in rubrerythrin by the close apposition of a residue capable of facilitating proton transfer to the activated oxygen (in a hydrophobic cavity adjacent to the diiron center based on the crystal structure of the oxygen-binding mimic azide). Here we report that desaturase mutant T199D binds substrate but its desaturase activity decreases by ≈2 × 103-fold. However, it shows a >31-fold increase in peroxide-dependent oxidase activity with respect to WT desaturase, as monitored by single-turnover stopped-flow spectrometry. A 2.65-Å crystal structure of T199D reveals active-site geometry remarkably similar to that of rubrerythrin, consistent with its enhanced function as an oxidase enzyme. That a single amino acid substitution can switch reactivity from desaturation to oxidation provides experimental support for the hypothesis that the desaturase evolved from an ancestral oxidase enzyme. PMID:17088542

Differences in muscle oxygenation, perceived fatigue and recovery between long-track and short-track speed skating

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Florentina Johanna Hettinga

2016-12-01

Full Text Available Due to the technical nature of speed skating, that is affecting physiological mechanisms such as oxygenation and blood flow, this sport provides a unique setting allowing us to uncover novel mechanistic insights of the physiological response to exercise in elite middle-distance and endurance sports. The present study aimed to examine the influence of skating mode (short-track vs. long-track on muscle oxygenation, perceived fatigue, and recovery in elite speed skating. Muscle oxygenation of twelve talented short-track speed skaters was continuously monitored during a long-track (LT and a short-track (ST skating time-trials of maximal effort using near-infrared spectroscopy (NIRS on the m. vastus lateralis for both legs. Video captures were made of each testing session for further interpretation of the muscle oxygenation. To determine recovery, perceived exertion was measured two and four hours after each testing sessions. Repeated measures ANOVA’s were used for statistical analysis (p<.05. After a rapid desaturation in both legs directly after the start, an asymmetry in muscle oxygenation between both legs was found during LT (tissue saturation-index (TSI%-slope: left=0.053±0.032; right=0.023±0.020, p<.05 and ST speed skating (TSI%-slope: left=0.050±0,052, right=0.001 ±0.053, p<.05. Re-Resaturation of the right leg was relatively lower in ST compared to LT. For the left leg, no difference was found between skating modes in muscle oxygenation. Respectively, two (ST=5.8±2.0; LT=4.2±1.5 and four hours (ST=4.6±1.9; LT=3.1±1.6 after the time-trials, a higher rate of perceived exertion was found for ST. Based on our results, ST seems more physiologically demanding, and longer periods of recovery are needed after training compared to LT. Technical aspects unique to the exercise mode seem to impact on oxygenation, affecting processes related to the regulation of exercise intensity such as fatigue and recovery.

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

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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.

Hypercapnic Respiratory Acidosis During An In-Flight Oxygen Assessment.

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Spurling, Kristofer J; Moonsie, Ian K; Perks, Joseph L

2016-02-01

Patients with respiratory disease are at risk of excessive hypoxemia in the hypobaric commercial aircraft cabin environment, and the consensus is that this is easily corrected with supplementary oxygen. However, despite the risks of hypercapnia with increasing inspired oxygen in some patients being well established, this issue is not currently addressed in medical guidelines for air travel. A 76-yr-old woman with chronic type 2 respiratory failure underwent hypoxic challenge testing (HCT) to assess in-flight oxygen requirements. She is stable on home ventilation, and baseline arterial blood gases showed mild hypoxemia (Pao2 9.12 kPa), normal P(a)co(2) (5.64 kPa) and pH (7.36) with 98% S(p)O(2). HCT was performed delivering 15% FIo(2) via a mask, and the patient desaturated to respiratory acidosis (pH 7.25). The patient was advised against flying due to hypoxemia during HCT and the precipitous drop in pH on oxygen. It is possible to hyperoxygenate patients with type 2 respiratory failure in flight with the minimum level of supplementary oxygen available on many aircraft. In these cases P(a)co(2) and pH should be scrutinized during HCT before recommending in-flight oxygen. No current guidelines discuss the risk of hypercapnia from in-flight oxygen; it is therefore recommended that this be addressed in future revisions of medical air travel guidelines, should further research indicate it.

Apnoeic-hypopnoeic episodes during obstructive sleep apnoea are associated with histological nonalcoholic steatohepatitis.

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Mishra, Poonam; Nugent, Clarke; Afendy, Arian; Bai, Chunhong; Bhatia, Priya; Afendy, Mariam; Fang, Yun; Elariny, Hazem; Goodman, Zachary; Younossi, Zobair M

2008-09-01

Nonalcoholic fatty liver disease (NAFLD) and obstructive sleep apnoea are associated with metabolic syndrome and atherosclerotic heart disease. This study evaluates the potential association between the NAFLD subtypes and a number of polysomnographical (PSG) parameters. This study included patients undergoing bariatric surgery with extensive clinical and histological data for whom complete PSG data before surgery were also available. Excess alcohol intake and other causes of liver disease were excluded. Apnoea, hypopnoea and apnoea-hypopnoea index (AHI) were calculated as described previously. In this study, a total of 101 patients [77 nonalcoholic steatohepatitis (NASH) and 22 non-NASH controls] with PSG data were included (age 42.9 +/- 11.4 years, body mass index 51.6 +/- 9.5 kg/m(2), fasting serum glucose 117.4 +/- 53.4 mg/dl, fasting serum triglycerides 171.3 +/- 82.9 mg/dl, 58% hypertension and 33% diabetes mellitus). Subjects with histological NASH had significantly lower lowest desaturation (77 vs. 85%, P=0.006), lower mean nocturnal oxygen saturation (91 vs. 93%, P=0.05), higher AHI (35 vs. 22, P=0.03), higher respiratory disturbance index (46 vs. 21, P=0.02) and higher alanine aminotransferase/aspartate aminotransferase ratio (1.4 vs. 1.3, P=0.05) compared with non-NASH controls. In multivariate analysis, the lowest desaturation (P=0.04) was independently associated with histological NASH. Lowest desaturation and mean nocturnal oxygen saturation were significantly lower in subjects with fibrosis (76 vs. 85%, P=0.004 and 90.4 vs. 93.0%, P=0.02). Our results suggest that the frequent nocturnal hypoxic episodes in NAFLD patients may be a risk factor for developing NASH. Additional studies are needed to study the effect of optimizing sleep apnoea management on the outcomes of patients with NAFLD.

Association of obstructive sleep apnea with homocystein, nitric oxide and total antioxidant capacity levels in patients with or without coronary artery disease.

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Ortaç Ersoy, Ebru; Fırat, Hikmet; Akaydın, Sevgi; Özkan, Yeşim; Durusu, Mine; Darılmaz Yüce, Gülbahar; Ergün, Recai; Topeli, Arzu; Ardıç, Sadık

2014-01-01

Obstructive sleep apnea (OSA) is associated with cardiovascular morbidity and mortality. Deficiency of nitric oxide (NO) and plasma levels of homocystein have been implicated in the pathogenesis of cardiovascular disease. OSA results in oxygen desaturation and arousal from sleep. Free oxygen radicals can be produced by hypoxia-reoxygenation. To test for the hypothesis that OSA is associated with cardiovascular morbidity, we investigated levels of homocystein, NO and total antioxidant capacity in OSA patients with and without coronary artery disease (CAD) in comparison with normal subjects and patients with CAD without OSA. Polysomnography was performed in 27 patients who had a myocardial infarction and in 25 patients without evidence of CAD. Patients were grouped according their polysomnography results as OSA with CAD (group 1), OSA without CAD (group 2), CAD (group 3), and normal (group 4) . Levels of homocystein, NO and total antioxidant capacity were determined after an overnight fasting. Data were analysed with parametric and non parametric statistical tests. According to apnea-hypopnea index (AHI) 44.4% of CAD patients were OSA. After polysomnographic evaluation, the patients were re-distributed as follows: OSA with CAD (n= 12), OSA without CAD (n= 14), CAD (n= 15), and normal (n= 11). Homocystein levels were higher in 3 groups compared to controls. AHI, MDI and desaturation time was higher in three -vessel disease compared to one and two- vessel diseases (p< 0.05). NO levels were correlated with the period of oxygen desaturation (r: -0.45, p= 0.031). The antioxidant capacity did not differ between OSA and healthy groups. OSA is frequent in CAD. AHI, MDI and desaturation time are higher in patients with severe CAD. It is important to evaluate OSA patients for CAD.

Comparability of pulse oximeters used in sleep medicine for the screening of OSA

International Nuclear Information System (INIS)

Böhning, N; Schultheiß, B; Eilers, S; Schmittendorf, E; Penzel, T; Böhning, W

2010-01-01

Obstructive sleep apnea syndrome (OSA) is a frequent clinical picture. It is characterized by repetitive respiratory arrest with a consecutive decrease in arterial oxygen saturation (SaO 2 ). In clinical practice, the number of desaturations per hour, oxygen desaturation index (ODI), is used as an important diagnostic criterion. Medical literature, however, mentions different threshold values that are defined as pathological. By means of systematic comparative measurements, the study presented here will examine to what extent the diagnosis and the quantification of OSA severity are affected by the device-specific measurement technique, thus impacting the predictive value of nighttime pulse oximetry in outpatient OSA screening. Different pulse oximeters commonly used in clinical practice were analyzed comparatively regarding technical parameters, temporal dynamics and the reproducibility of measuring results. The measurements were executed simultaneously and time synchronized in a reference group of five test subjects (four males, one female, average age 33.0 ± 9.4 years), in a group of five patients (all males, average age 51.8 ± 18.4 years) and using a simulator (pulse oximeter simulator index 2). All devices underestimate the simulator's predetermined oxygen desaturation of 10%. The dispersion of values is high. The device-specific characteristics have a significant influence on the collected data. The fundamental weakness of the systems lies in the reproducibility of measuring results (this only seems adequate at a signal resolution in steps of 0.1%) as well as the differing temporal dynamics. In the synchronous use of different systems on patients for the purpose of a direct comparison of devices, the dispersion of values is serious, reaching a fluctuation range of up to factor 1.42. In measuring dynamic events (apneas), different pulse oximeters do not record identical values. This is due to the different internal signal processing of the devices

Study on the effect of hyperbaric oxygen therapy on the wound healing and the related serum indexes of rectal abscess patients after surgery

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Bo Mo, Qing He

2016-07-01

Full Text Available Objective: To observe and research the influence degree of hyperbaric oxygen therapy on wound healing and related serum indexes of rectal abscess patients after surgery. Methods: A total of 48 rectal abscess patients treated with operation in my hospital from April 2014 to August 2015 were taken as research objects, and the 48 patients were randomly divided into two groups: control group (postoperative routine treatments, 24 cases and observation group (postoperative routine treatments and hyperbaric oxygen therapy, 24 cases, and then compared the time constitutes of wound healing, the edema degrees and the related serum indexes of patients in two test groups before the operation and at 1 d, 3 d and 10 d after operation. Results: The time constitute of wound healing of observation group is better than that of control group, and the edema degree and the related serum index of observation group are lower than those of control group, and the test result of two groups have significant differences. Conclusions: The hyperbaric oxygenation therapy can effectively promote the postoperative wound healing of patients with rectal abscess, and it also has active clinical significance for the control of edema and related serum indexes.

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

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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

Long-term oxygen therapy: Are we prescribing appropriately?

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Mª Rosa Güell Rous

2008-06-01

Full Text Available Mª Rosa Güell RousDepartament de Pneumologia, Hospital de la Santa Creu I de Sant Pau, Barcelona, SpainAbstract: Long-term oxygen therapy (LTOT is the treatment proven to improve survival in chronic obstructive pulmonary disease (COPD patients with chronic respiratory failure. It also appears to reduce the number of hospitalizations, increase effort capacity, and improve health-related quality of life. Standard LTOT criteria are related to COPD patients who have PaO2 <60 mmHg, are in a clinical stable situation, and are receiving optimal pharmacological treatment. According to LTOT guidelines, oxygen should be prescribed for at least 18 hours per day although some authors consider 24 hours would be more beneficial. The benefits of LTOT depend on correction of hypoxemia. Arterial blood gases should be measured at rest. During exercise, an effort test should be done to assure adequate SaO2. During sleep, continuous monitoring of SaO2 and PaCO2 should be performed to confirm correction of SaO2 overnight. An arterial blood gas sample should be taken at awakening to assess PaCO2 in order to prevent hypoventilation from the oxygen therapy. Several issues that need to be addressed are the use of LTOT in COPD patients with moderate hypoxemia, the efficacy of LTOT in patients who desaturate during exercise or during sleep, the optimal dosage of oxygen supplementation, LTOT compliance, and the LTOT prescription in diseases other than COPD.Keywords: long-term oxygen therapy, COPD, oxygen supplementation, chronic respiratory failure, hypoxemia

Choice of oximeter affects apnea-hypopnea index.

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Zafar, Subooha; Ayappa, Indu; Norman, Robert G; Krieger, Ana C; Walsleben, Joyce A; Rapoport, David M

2005-01-01

Current Medicare guidelines include an apnea-hypopnea index (AHI) > or = 15 events per hour, in which all hypopneas must be associated with 4% desaturation, to qualify for reimbursement for therapy with continuous positive airway pressure (CPAP). The present data demonstrate the effect of pulse oximeter differences on AHI. Prospective study, blinded analysis. Academic sleep disorder center. One hundred thirteen consecutive patients (84 men and 29 women) undergoing diagnostic sleep studies and being evaluated for CPAP based on the Medicare indications for reimbursement. Patients had two of four commonly used oximeters with signal averaging times of 4 to 6 s placed on different digits of the same hand during nocturnal polysomnography. Apneas and candidate hypopneas (amplitude reduction, > 30%) were scored from the nasal cannula airflow signal without reference to oximetry. Candidate hypopneas then were reclassified as hypopneas by each oximeter if they were associated with a 4% desaturation. Although the use of three oximeters resulted in a similar AHI (bias, oximeter showed an overall increase in AHI of 3.7 events per hour. This caused 7 of 113 patients to have an AHI of > or = 15 events per hour (meeting the Medicare criteria for treatment) by one oximeter but not when a different oximeter was used. More importantly, when our analysis was limited to those patients whose number of candidate hypopneas made them susceptible to the threshold value of 15 events per hour, 7 of 35 patients who did not meet the Medicare AHI standard for treatment by one oximeter were reclassified when a different oximeter was used. In the present study, oximeter choice affected whether the AHI reached the critical cutoff of 15 events per hour, particularly in those with disease severity that was neither very mild nor very severe. As oximetry is not a technique that produces a generic result, there are significant limitations to basing the definition of hypopnea on a fixed percentage of

Combined Orthodontic and Surgical Treatment in a 8-Years-Old Patient Affected By Severe Obstructive Sleep Apnea: A Case-Report.

Science.gov (United States)

Gracco, Antonio; Bruno, Giovanni; de Stefani, Alberto; Ragona, Rosario Marchese; Mazzoleni, Sergio; Stellini, Edoardo

An eight-years-old girl showed a restless sleep with snoring and severe apnea episodes, a mandibular retrognathia, mouth breathing, maxillary transverse discrepancy, mandibular transverse discrepancy, moderate crowding and anterior open-bite. The CBCT showed an anterior collapse of the epiglottis. The treatment consisted in a rapid palatal expansion, an epiglottoplasty and a reduction of the tongue base. Polysomnography revealed that apnea-hypopnea index improved from 21,8 episodes/hr at the baseline to 0,6 episodes/hr, average oxygen saturation from 96,5% to 98,1%, oxygen desaturation events from 23,4 episodes/hr to 1/hr.

Oscillation of tissue oxygen index in non-exercising muscle during exercise.

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Yano, T; Afroundeh, R; Shirakawa, K; Lian, C-S; Shibata, K; Xiao, Z; Yunoki, T

2015-09-01

The purpose of the present study was to examine how oscillation of tissue oxygen index (TOI) in non-exercising exercise is affected during high-intensity and low-intensity exercises. Three exercises were performed with exercise intensities of 30% and 70% peak oxygen uptake (Vo(2)peak) for 12 min and with exercise intensity of 70% Vo(2)peak for 30 s. TOI in non-exercising muscle (biceps brachii) during the exercises for 12 min was determined by nearinfrared spectroscopy. TOI in the non-exercising muscle during the exercises was analyzed by fast Fourier transform (FFT) to obtain power spectra density (PSD). The frequency at which maximal PSD appeared (Fmax) during the exercise with 70% Vo(2)peak for 12 min (0.00477 ± 0.00172 Hz) was significantly lower than that during the exercise with 30% Vo2peak for 12 min (0.00781 ± 0.00338 Hz). There were significant differences in blood pH and blood lactate between the exercise with 70% Vo(2)peak and the exercise with 30% Vo(2)peak. It is concluded that TOI in nonexercising muscle oscillates during low-intensity exercise as well as during high-intensity exercise and that the difference in Fmax between the two exercises is associated with the difference in increase in blood lactate derived from the exercise.

Variations in alveolar partial pressure for carbon dioxide and oxygen have additive not synergistic acute effects on human pulmonary vasoconstriction.

Science.gov (United States)

Croft, Quentin P P; Formenti, Federico; Talbot, Nick P; Lunn, Daniel; Robbins, Peter A; Dorrington, Keith L

2013-01-01

The human pulmonary vasculature constricts in response to hypercapnia and hypoxia, with important consequences for homeostasis and adaptation. One function of these responses is to direct blood flow away from poorly-ventilated regions of the lung. In humans it is not known whether the stimuli of hypercapnia and hypoxia constrict the pulmonary blood vessels independently of each other or whether they act synergistically, such that the combination of hypercapnia and hypoxia is more effective than the sum of the responses to each stimulus on its own. We independently controlled the alveolar partial pressures of carbon dioxide (Paco 2) and oxygen (Pao 2) to examine their possible interaction on human pulmonary vasoconstriction. Nine volunteers each experienced sixteen possible combinations of four levels of Paco 2 (+6, +1, -4 and -9 mmHg, relative to baseline) with four levels of Pao 2 (175, 100, 75 and 50 mmHg). During each of these sixteen protocols Doppler echocardiography was used to evaluate cardiac output and systolic tricuspid pressure gradient, an index of pulmonary vasoconstriction. The degree of constriction varied linearly with both Paco 2 and the calculated haemoglobin oxygen desaturation (1-So2). Mixed effects modelling delivered coefficients defining the interdependence of cardiac output, systolic tricuspid pressure gradient, ventilation, Paco 2 and So2. No interaction was observed in the effects on pulmonary vasoconstriction of carbon dioxide and oxygen (p>0.64). Direct effects of the alveolar gases on systolic tricuspid pressure gradient greatly exceeded indirect effects arising from concurrent changes in cardiac output.

Postnatal follow-up of the oxygenation index, arterial to alveolar oxygen tension ratio and alveolar arterial oxygen tension difference values in neonates with the respiratory distress syndrome treated with conventional ventilatory support.

Science.gov (United States)

Atanasov, A; Despotova-Toleva, L

1997-01-01

Recent development of sophisticated intensive care technique for use in newborn infants with the respiratory distress syndrome (RDS) has resulted in changes in the therapeutic strategies and moved the problem of neonatal survival into the realm of new therapeutic realities. At present, the mechanical ventilation methods form an integral part of the intensive care strategy of infants with RDS. They have come to the forefront of infant care because of their successful use in ventilatory support and children survival where other therapeutic modalities have failed. The present prospective observational longitudinal study was designed to assess the real-time convenience, reliability and accuracy of the changes in the oxygenation index (OI), arterial-to-alveolar oxygen tension ratio (a/A PO2) and alveolar-arterial oxygen gradient (A-a)DO2 in ventilator-dependent neonates with RDS, to analyze their feasibility and potential information yield in oxygen inhalation therapy as well as their prognostic implications and predictive value. Twenty neonates with RDS, heralded by respiratory failure which necessitated the initiation of oxygen inhalation therapy and ventilatory support within 24 hours of birth, were enrolled in the study. Ten of the infants survived and the remaining ten died. OI, (a/A PO2) and (A-a)DO2 were followed up sequentially and thoroughly analyzed as the primary outcome measures of the study. The indices were calculated on the basis of the complete monitoring of the ventilatory equipment parameters and acid-base status carried out on an hourly basis. Our results show that: 1. The combination of three indexes (OI, (a/A)PO2 and (A-a)DO2 we propose is a useful discriminating predictor of neonatal lung maturity reflecting arterial blood gas status in ventilator-dependent neonates with RDS. 2. The indices detect the efficacy of the modern conventional ventilatory support with real-time convenience and reliable accuracy forming the cornerstone of clinical decision

Succinylcholine versus rocuronium for rapid sequence intubation in intensive care: a prospective, randomized controlled trial

Science.gov (United States)

2011-01-01

Introduction Succinylcholine and rocuronium are widely used to facilitate rapid sequence induction (RSI) intubation in intensive care. Concerns relate to the side effects of succinylcholine and to slower onset and inferior intubation conditions associated with rocuronium. So far, succinylcholine and rocuronium have not been compared in an adequately powered randomized trial in intensive care. Accordingly, the aim of the present study was to compare the incidence of hypoxemia after rocuronium or succinylcholine in critically ill patients requiring an emergent RSI. Methods This was a prospective randomized controlled single-blind trial conducted from 2006 to 2010 at the University Hospital of Basel. Participants were 401 critically ill patients requiring emergent RSI. Patients were randomized to receive 1 mg/kg succinylcholine or 0.6 mg/kg rocuronium for neuromuscular blockade. The primary outcome was the incidence of oxygen desaturations defined as a decrease in oxygen saturation ≥ 5%, assessed by continuous pulse oxymetry, at any time between the start of the induction sequence and two minutes after the completion of the intubation. A severe oxygen desaturation was defined as a decrease in oxygen saturation ≥ 5% leading to a saturation value of ≤ 80%. Results There was no difference between succinylcholine and rocuronium regarding oxygen desaturations (succinylcholine 73/196; rocuronium 66/195; P = 0.67); severe oxygen desaturations (succinylcholine 20/196; rocuronium 20/195; P = 1.0); and extent of oxygen desaturations (succinylcholine -14 ± 12%; rocuronium -16 ± 13%; P = 0.77). The duration of the intubation sequence was shorter after succinycholine than after rocuronium (81 ± 38 sec versus 95 ± 48 sec; P = 0.002). Intubation conditions (succinylcholine 8.3 ± 0.8; rocuronium 8.2 ± 0.9; P = 0.7) and failed first intubation attempts (succinylcholine 32/200; rocuronium 36/201; P = 1.0) did not differ between the groups. Conclusions In critically ill

Cerebral oxygen desaturation during beach chair position

NARCIS (Netherlands)

Moerman, Annelies T.; de Hert, Stefan G.; Jacobs, Tom F.; de Wilde, Lieven F.; Wouters, Patrick F.

2012-01-01

Cases of ischaemic brain damage have been reported in relatively healthy patients undergoing shoulder surgery in the beach chair position. Unrecognised cerebral hypoperfusion may have contributed to these catastrophic events, indicating that routine anaesthesia monitoring may not suffice.

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.

Longitudinal Changes in Physical Activity Level, Body Mass Index, and Oxygen Uptake Among Norwegian Adolescents

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Pål Lagestad

2018-03-01

Full Text Available Several studies have investigated activity levels among adolescents, but no study has examined longitudinal changes in physical activity (PA level, body mass, and oxygen uptake among the same adolescents from the age of 14 to 19 years. The present study examined data from a research project that included a group of randomly selected students (N = 116 with objective measurements of PA (accelerometer data, self-reported PA level, and body mass and oxygen uptake during a 5-year period. The results show a significant decrease in the accelerometer-based PA level over time, from age 14 to 19. At 14 years of age, the minutes of moderate and/or vigorous PA was 66.7 min·day−1, but was less than half, at only 24.4 min·day−1, at 19 years of age. The self-reported activity data show a decrease in girls’ general activity level over time, while boys’ activity level during school breaks decreased strongly during the period: at age 14, 61% of the boys were classified as active, while at age 19, only 11% were physically active. Furthermore, body mass index increased during the period for both genders, while oxygen uptake decreased. Since both BMI and maximal oxygen uptake are important risk factors for future CVD, these findings point toward the importance of maintaining a high activity level during childhood and adolescence, in order to keep fit later in life.

Exercise capacity in the Bidirectional Glenn physiology: Coupling cardiac index, ventricular function and oxygen extraction ratio.

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Vallecilla, Carolina; Khiabani, Reza H; Trusty, Phillip; Sandoval, Néstor; Fogel, Mark; Briceño, Juan Carlos; Yoganathan, Ajit P

2015-07-16

In Bi-directional Glenn (BDG) physiology, the superior systemic circulation and pulmonary circulation are in series. Consequently, only blood from the superior vena cava is oxygenated in the lungs. Oxygenated blood then travels to the ventricle where it is mixed with blood returning from the lower body. Therefore, incremental changes in oxygen extraction ratio (OER) could compromise exercise tolerance. In this study, the effect of exercise on the hemodynamic and ventricular performance of BDG physiology was investigated using clinical patient data as inputs for a lumped parameter model coupled with oxygenation equations. Changes in cardiac index, Qp/Qs, systemic pressure, oxygen extraction ratio and ventricular/vascular coupling ratio were calculated for three different exercise levels. The patient cohort (n=29) was sub-grouped by age and pulmonary vascular resistance (PVR) at rest. It was observed that the changes in exercise tolerance are significant in both comparisons, but most significant when sub-grouped by PVR at rest. Results showed that patients over 2 years old with high PVR are above or close to the upper tolerable limit of OER (0.32) at baseline. Patients with high PVR at rest had very poor exercise tolerance while patients with low PVR at rest could tolerate low exercise conditions. In general, ventricular function of SV patients is too poor to increase CI and fulfill exercise requirements. The presented mathematical model provides a framework to estimate the hemodynamic performance of BDG patients at different exercise levels according to patient specific data. Published by Elsevier Ltd.

The Relationship Between Oxygen Reserve Index and Arterial Partial Pressure of Oxygen During Surgery.

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Applegate, Richard L; Dorotta, Ihab L; Wells, Briana; Juma, David; Applegate, Patricia M

2016-09-01

The use of intraoperative pulse oximetry (SpO2) enhances hypoxia detection and is associated with fewer perioperative hypoxic events. However, SpO2 may be reported as 98% when arterial partial pressure of oxygen (PaO2) is as low as 70 mm Hg. Therefore, SpO2 may not provide advance warning of falling arterial oxygenation until PaO2 approaches this level. Multiwave pulse co-oximetry can provide a calculated oxygen reserve index (ORI) that may add to information from pulse oximetry when SpO2 is >98%. This study evaluates the ORI to PaO2 relationship during surgery. We studied patients undergoing scheduled surgery in which arterial catheterization and intraoperative arterial blood gas analysis were planned. Data from multiple pulse co-oximetry sensors on each patient were continuously collected and stored on a research computer. Regression analysis was used to compare ORI with PaO2 obtained from each arterial blood gas measurement and changes in ORI with changes in PaO2 from sequential measurements. Linear mixed-effects regression models for repeated measures were then used to account for within-subject correlation across the repeatedly measured PaO2 and ORI and for the unequal time intervals of PaO2 determination over elapsed surgical time. Regression plots were inspected for ORI values corresponding to PaO2 of 100 and 150 mm Hg. ORI and PaO2 were compared using mixed-effects models with a subject-specific random intercept. ORI values and PaO2 measurements were obtained from intraoperative data collected from 106 patients. Regression analysis showed that the ORI to PaO2 relationship was stronger for PaO2 to 240 mm Hg (r = 0.536) than for PaO2 over 240 mm Hg (r = 0.0016). Measured PaO2 was ≥100 mm Hg for all ORI over 0.24. Measured PaO2 was ≥150 mm Hg in 96.6% of samples when ORI was over 0.55. A random intercept variance component linear mixed-effects model for repeated measures indicated that PaO2 was significantly related to ORI (β[95% confidence interval] = 0

Can telemetry data obviate the need for sleep studies in Pierre Robin Sequence?

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Aaronson, Nicole Leigh; Jabbour, Noel

2017-09-01

This study looks to correlate telemetry data gathered on patients with Pierre Robin Sequence (PRS) with sleep study data. Strong correlation might allow obstructive sleep apnea (OSA) to be reasonably predicted without the need for sleep study. Charts from forty-six infants with PRS who presented to our children's hospital between 2005 and 2015 and received a polysomnogram (PSG) prior to surgical intervention were retrospectively reviewed. Correlations and scatterplots were used to compare average daily oxygen nadir, overall oxygen nadir, and average number of daily desaturations from telemetry data with apnea-hypopnea index (AHI) and oxygen nadir on sleep study. Results were also categorized into groups of AHI ≥ or sleep study data. Patients with O2 nadir below 80% on telemetry were not more likely to have an O2 nadir below 80% on sleep study. Patients with an average O2 nadir below 80% did show some correlation with having an AHI greater than 10 on sleep study but this relationship did not reach significance. Of 22 patients who did not have any desaturations on telemetry below 80%, 16 (73%) had an AHI >10 on sleep study. In the workup of infants with PRS, the index of suspicion is high for OSA. In our series, telemetry data was not useful in ruling out severe OSA. Thus our data do not support forgoing sleep study in patients with PRS and concern for OSA despite normal telemetry patterns. Copyright © 2017 Elsevier B.V. All rights reserved.

The unresolved issue of oxygen therapy in lung fibrosis: Some clues from a Spanish cohort

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Irene Martin-Robles

2014-01-01

Full Text Available Indication of oxygen therapy in fibrotic interstitial lung diseases is not standardized and its specific requirements are not well defined. The objective of this study was to evaluate ambulatory oxygen therapy features in lung fibrotic patients. Clinical and exploratory　data, including 6-minute walking test and pulmonary hypertension, from one hundred and seven patients with fibrotic interstitial lung disease that received ambulatory oxygen treatment were studied. In up to 40% of cases the prescription of oxygen therapy was made after performing a 6-minute walking test. Patients who required ambulatory oxygen only during exercise presented a mild to moderate reduction of the predicted % FVC (62.1 ± 19 and DLCO (49 ± 14.4 while patients who had respiratory failure at rest (mean PaO2 51.9 ± 6.7 presented a moderate reduction of %FVC (56.8 ± 15.6 but a severe decrease of %DLCO (31.67 ± 12. Pulmonary hypertension (PH was evaluated in 47.7% of patients and occurred in 60.8% of them. In conclusion, there is no pulmonary functional predictor of oxyhaemoglobin desaturation during exercise. PH is frequently associated with interstitial lung diseases, mainly when respiratory failure at rest appears. The heterogeneity of the patients and limitation of retrospective studies could be the cause of the tributes for potential benefits of oxygen treatment in interstitial lung diseases.

Relationship Between Cerebral Oxygenation and Hemodynamic and Oxygen Transport Parameters in Surgery for Acquired Heart Diseases

Directory of Open Access Journals (Sweden)

A. I. Lenkin

2012-01-01

Full Text Available Objective: to evaluate the relationship between cerebral oxygenation and hemodynamic and oxygen transport parameters in surgical correction of concomitant acquired heart diseases. Subjects and methods. Informed consent was received from 40 patients who required surgery because of concomitant (two or more acquired heart defects. During procedure, perioperative monitoring of oxygen transport and cerebral oxygenation was performed with the aid of PiCCO2 monitor (Pulsion Medical Systems, Germany and a Fore-Sight cerebral oximeter (CASMED, USA. Anesthesia was maintained with propofol and fen-tanyl, by monitoring the depth of anesthesia. Early postoperative intensive therapy was based on the protocol for early targeted correction of hemodynamic disorders. Oxygen transport and cerebral oxygenation parameters were estimated intraopera-tively and within 24 postoperative hours. A statistical analysis including evaluation of Spearman correlations was performed with the aid of SPSS 15.0. Results. During perfusion, there was a relationship between cerebral oximetry values and hemat-ocrit levels, and oxygen partial pressure in the venous blood. Furthermore, a negative correlation between cerebral oximetry values and blood lactate levels was found 30 minutes after initiation of extracorporeal circulation (EC. During the study, there was a positive correlation between cerebral oxygenation and values of cardiac index, central venous saturation, and oxygen delivery index. There was a negative relationship between cerebral oxygenation and extravascular lung water at the beginning of surgery and a correlation between cerebral oximetry values and oxygenation index by the end of the first 24 postoperative hours. Conclusion. The cerebral oxygenation values correlate -with the main determinants of oxygen transport during EC and after cardiac surgical procedures. Cerebral oximetry may be used in early targeted therapy for the surgical correction of acquired combined

Dynamic mechanisms of cardiac oxygenation during brief ischemia and reperfusion

International Nuclear Information System (INIS)

Parsons, W.J.; Rembert, J.C.; Bauman, R.P.; Greenfield, J.C. Jr.; Piantadosi, C.A.

1990-01-01

Myocardial oxygenation may be altered markedly by changes in tissue blood flow. During brief ischemia and reperfusion produced by transient occlusion of the left anterior descending artery in 10 open-chest dogs, changes in the oxygenation of tissue hemoglobin (Hb) plus myoglobin (Mb) and the oxidation-reduction (redox) state of mitochondrial cytochrome aa3 were monitored continuously using near-infrared spectroscopy. The nondestructive optical technique indicated that coronary occlusion produced an abrupt drop in tissue oxygen stores (tHb02 + Mb02), tissue blood volume (tBV), and the oxidation level of cytochrome aa3. Changes in the cytochrome oxidation state were related inversely to transmural collateral blood flow within the ischemic region (r = 0.77) measured with radiolabeled microspheres. Furthermore, there was a direct relationship (r = 0.91) between collateral blood flow and the tissue level of desaturated Hb and Mb (tHb + Mb). Reperfusion after 2 min of ischemia led to a synchronous overshoot of baseline in coronary flow and tBV followed by supranormal increases in tHb + Mb02 and the oxidation level of cytochrome aa3. The tHb + Mb level increased transiently during reperfusion. This response correlated inversely with collateral flow during ischemia (r = 0.91). Accordingly, the time required to reach peak tHb + Mb levels was shortest in dogs with high collateral flows (r = 0.75). Thus collateral blood flow partially sustains myocardial oxygenation during coronary artery occlusion and influences tissue reoxygenation early during reperfusion

Risk of secondary lymphedema in breast cancer survivors is related to serum phospholipid fatty acid desaturation.

Science.gov (United States)

Ryu, Eunjung; Yim, Seung Yun; Do, Hyun Ju; Lim, Jae-Young; Yang, Eun Joo; Shin, Min-Jeong; Lee, Seung-Min

2016-09-01

Secondary lymphedema is a common irreversible side effect of breast cancer surgery. We investigated if risk of secondary lymphedema in breast cancer survivors was related to changes in serum phospholipid fatty acid composition. Study subjects were voluntarily recruited into the following three groups: breast cancer survivors who had sentinel lymph node biopsy without lymphedema (SLNB), those who had auxillary lymph node dissection without lymphedema (ALND), and those who had ALND with lymphedema (ALND + LE). Body mass index (BMI), serum lipid profiles, bioimpedance data with single-frequency bioimpedance analysis (SFBIA), and serum phospholipid compositions were analyzed and compared among the groups. BMI, serum total cholesterol (total-C), and low-density lipoprotein cholesterol (LDL-C) and SFBIA ratios increased only in the ALND + LE. High polyunsaturated fatty acids (PUFAs) and high C20:4 to C18:2 n-6 PUFAs (arachidonic acid [AA]/linoleic acid [LA]) was detected in the ALND and ALND + LE groups compared to SLNB. The ALND + LE group showed increased activity indices for delta 6 desaturase (D6D) and D5D and increased ratio of AA to eicosapentaenoic acid (AA/EPA) compared to the ALND and SLNB groups. Correlation and regression analysis indicated that D6D, D5D, and AA/EPA were associated with SFBIA ratios. We demonstrated that breast cancer survivors with lymphedema had elevated total PUFAs, fatty acid desaturase activity indices, and AA/EPA in serum phospholipids. Our findings suggested that desaturation extent of fatty acid composition might be related to the risk of secondary lymphedema in breast cancer survivors.

Experience of severe desaturation during anesthetic induction period in an obese adult patient with Prader-Willi syndrome -A case report-.

Science.gov (United States)

Choi, Joon Woo; Kim, Eun-Ju; Min, Byung Woo; Ban, Jong Seouk; Lee, Sang Gon; Lee, Ji-Hyang

2012-02-01

Prader-Willi syndrome is characterized by infantile hypotonia, childhood-onset obesity, short stature, mental retardation, hyperphagia, hypogonadism. After infantile hypotonia phase, patient is prone to morbid obesity due to hyperphagia. Complications associated with morbid obesity are recognized as the main risk factors for death the lifespan of patients with Prader-Willi syndrome. We experienced desaturation and bronchospasm during arteriovenous fistula surgery in an obese adult with Prader-Willi syndrome.

Desaturation of skeletal muscle structural and depot lipids in obese individuals during a very-low-calorie diet intervention

DEFF Research Database (Denmark)

Haugaard, Steen B; Vaag, Allan; Høy, Carl-Erik

2007-01-01

would decrease saturated fatty acids (FAs) and increase long-chain polyunsaturated FAs (LCPUFAs) in muscular structural lipids, as such changes have been associated with improved insulin sensitivity. RESEARCH METHODS AND PROCEDURES: Skeletal muscle biopsies (vastus lateralis) were obtained from 13 obese...... during the VLCD. DISCUSSION: Desaturation of both muscle cell membrane phospholipid and IMTG was significant but modest during a VLCD in obese subjects. Further research must delineate whether such changes in skeletal muscle structural and depot lipid composition themselves are enough to promote...

Desaturation of skeletal muscle structural and depot lipids in obese individuals during a very-low-calorie diet intervention

DEFF Research Database (Denmark)

Haugaard, S.B.; Vaag, A.; Høy, Carl-Erik

2007-01-01

would decrease saturated fatty acids (FAs) and increase long-chain polyunsaturated FAs (LCPUFAs) in muscular structural lipids, as such changes have been associated with improved insulin sensitivity. Research Methods and Procedures: Skeletal muscle biopsies (vastus lateralis) were obtained from 13 obese....... Discussion: Desaturation of both muscle cell membrane phospholipid and IMTG was significant but modest during a VLCD in obese subjects. Further research must delineate whether such changes in skeletal muscle structural and depot lipid composition themselves are enough to promote the observed improvements...

Use of a three dimensional network model to predict equilibrium desaturation properties of coal filter cakes

Energy Technology Data Exchange (ETDEWEB)

Qamar, I.; Bayles, G.A.; Tierney, J.W.; Chiang, S.-H.; Klinzing, G.E.

1987-01-01

A three dimensional bond-flow correlated network model has been successfully used to calculate equilibrium desaturation curves for coal filter cakes. A simple cubic lattice with the pore sizes correlated in the direction of macroscopic flow is used as the network. A new method of pore volume assignment is presented in which the pore volume occupied by the large pores (which give rise to capillary pressures less than a calculated critical value) is assigned to the nodes and the rest is distributed to the bonds according to an experimentally determined micrographic pore size distribution. Equilibrium desaturation curves for -32 mesh, -200 mesh and -100 + 200 mesh coal cakes (Pittsburgh Seam coal), formed with distilled water have been calculated. A bond flow correlation factor, F/sub c/ is introduced to account for channeling of the displacing fluid through high volume, low resistance flow paths - a phenomenon which is displayed by many real systems. It is determined that a single value of 0.6 for F/sub c/ is required for -32 mesh and -200 mesh coals. However, for -100 + 200 mesh coal, where all small as well as large particles have been removed, a value of 1.0 is required. The results of six -32 mesh cakes formed with surfactants show that the effect of surfactants can be accounted for by modifying one of the model parameters, the entry diameter correction. A correlation is presented to estimate the modified correction using experimentally determined surface tension and contact angle values. Further, the predicted final saturations agree with the experimental values within an average absolute error of 5%. 16 refs., 11 figs., 2 tabs.

Kinetic therapy improves oxygenation in critically ill pediatric patients.

Science.gov (United States)

Schultz, Theresa Ryan; Lin, Richard; Francis, Barbara A; Hales, Roberta L; Colborn, Shawn; Napoli, Linda A; Helfaer, Mark A

2005-07-01

To compare changes in oxygenation after manual turning and percussion (standard therapy) and after automated rotation and percussion (kinetic therapy). Randomized crossover trial. General and cardiac pediatric intensive care units. Intubated and mechanically ventilated pediatric patients who had an arterial catheter and no contraindications to using a PediDyne bed. Patients were placed on a PediDyne bed (Kinetic Concepts) and received 18 hrs blocks of standard and kinetic therapy in an order determined by randomization. Arterial blood gases were measured every 2 hrs during each phase of therapy. Oxygenation index and arterial-alveolar oxygen tension difference [P(A-a)O(2)] were calculated. Indexes calculated at baseline and after each 18-hr phase of therapy were analyzed. Fifty patients were enrolled. Data from 15 patients were either not collected or not used due to reasons that included violation of protocol and inability to tolerate the therapies in the study. Indexes of oxygenation were not normally distributed and were compared using Wilcoxon signed rank testing. Both therapies led to improvements in oxygenation, but only those from kinetic therapy achieved statistical significance. In patients receiving kinetic therapy first, median oxygenation index decreased from 7.4 to 6.19 (p = .015). The median P(A-a)O(2) decreased from 165.2 to 126.4 (p = .023). There were continued improvements in oxygenation after the subsequent period of standard therapy, with the median oxygenation index decreasing to 5.52 and median P(A-a)O(2) decreasing to 116.0, but these changes were not significant (p = .365 and .121, respectively). When standard therapy was first, the median oxygenation index decreased from 8.83 to 8.71 and the median P(a-a)o(2) decreased from 195.4 to 186.6. Neither change was significant. Median oxygenation index after the subsequent period of kinetic therapy was significantly lower (7.91, p = .044) and median P(A-a)O(2) trended lower (143.4, p = .077

Mechanisms controlling the oxygen consumption in experimentally induced hypochloremic alkalosis in calves.

Science.gov (United States)

Cambier, Carole; Clerbaux, Thierry; Amory, Hélène; Detry, Bruno; Florquin, Sandra; Marville, Vincent; Frans, Albert; Gustin, Pascal

2002-01-01

The study was carried out on healthy Friesian calves (n = 10) aged between 10 and 30 days. Hypochloremia and alkalosis were induced by intravenous administration of furosemide and isotonic sodium bicarbonate. The venous and arterial blood samples were collected repeatedly. 2,3-diphosphoglycerate (2,3-DPG), hemoglobin and plasmatic chloride concentrations were determined. The red blood cell chloride concentration was also calculated. pH, PCO2 and PO2 were measured in arterial and mixed venous blood. The oxygen equilibrium curve (OEC) was measured in standard conditions. The correspondence of the OEC to the arterial and mixed venous compartments was calculated, taking blood temperature, pH and PCO2 values into account. The oxygen exchange fraction (OEF%), corresponding to the degree of blood desaturation between the arterial and mixed venous compartments and the amount of oxygen released at the tissue level by 100 mL of blood (OEF Vol%) were calculated from the arterial and mixed venous OEC, combined with PO2 and hemoglobin concentration. Oxygen delivery (DO2) was calculated using the arterial oxygen content, the cardiac output measured by thermodilution, and the body weight of the animal. The oxygen consumption (VO2) was derived from the cardiac output, OEF Vol% and body weight values. Despite the plasma hypochloremia, the erythrocyte chloride concentration was not influenced by furosemide and sodium bicarbonate infusion. Due to the alkalosis-induced increase in the 2,3-DPG, the standard OEC was shifted to the right, allowing oxygen to dissociate from hemoglobin more rapidly. These changes opposed the increased affinity of hemoglobin for oxygen induced by alkalosis. Moreover, respiratory acidosis, hemoconcentration, and the slight decrease in the partial oxygen pressure in mixed venous blood (Pvo2) tended to improve the OEF Vol% and maintain the oxygen consumption in a physiological range while the cardiac output, and the oxygen delivery were significantly decreased

Hypoxic Challenge Testing (Fitness to Fly) in children with complex congenital heart disease.

Science.gov (United States)

Naqvi, Nitha; Doughty, Victoria L; Starling, Luke; Franklin, Rodney C; Ward, Simon; Daubeney, Piers E F; Balfour-Lynn, Ian M

2018-02-14

Commercial airplanes fly with an equivalent cabin fraction of inspired oxygen of 0.15, leading to reduced oxygen saturation (SpO 2 ) in passengers. How this affects children with complex congenital heart disease (CHD) is unknown. We conducted Hypoxic Challenge Testing (HCT) to assess need for inflight supplemental oxygen. Children aged heart rate, QT interval corrected for heart rate and partial pressure of carbon dioxide measured transcutaneously (PtcCO 2 ). A test failed when children with (1) normal baseline SpO 2 desaturated to 85%, (2) baseline SpO 2 85%-94% desaturated by 15% of baseline; and (3) baseline SpO 2 75%-84% desaturated to 70%. There were 68 children, mean age 3.3 years (range 10 weeks-14.5 years). Children with normal (n=36) baseline SpO 2 desaturated from median 99% to 91%, Pheart rate and QT interval corrected for heart rate were unaffected by the hypoxic state. This is the first evidence to help guide which children with CHD need a preflight HCT. We suggest all children with an actual or potential R-L shunt should be tested. © 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.

Beneficial Effects of Long-Term CPAP Treatment on Sleep Quality and Blood Pressure in Adherent Subjects With Obstructive Sleep Apnea.

Science.gov (United States)

Yang, Mei-Chen; Huang, Yi-Chih; Lan, Chou-Chin; Wu, Yao-Kuang; Huang, Kuo-Feng

2015-12-01

Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular diseases. Although CPAP is the first treatment choice for moderate-to-severe OSA, acceptance of and adherence to CPAP remain problematic. High CPAP adherence is generally defined as ≥4 h of use/night for ≥70% of the nights monitored. We investigated the long-term beneficial effects of CPAP on sleep quality and blood pressure in subjects with moderate-to-severe OSA according to high or low CPAP adherence. We retrospectively analyzed 121 subjects with moderate-to-severe OSA from August 2008 to July 2012. These subjects were divided into 3 groups: (1) no CPAP treatment (n = 29), (2) low CPAP adherence (n = 28), and (3) high CPAP adherence (n = 64). All subjects were followed up for at least 1 y. The 3 groups were compared regarding anthropometric and polysomnographic variables, presence of cardiovascular comorbidities, and blood pressure at baseline and at the last follow-up. The no-treatment group showed significant increases in oxygen desaturation index and blood pressure. The high-adherence group showed significant improvement in daytime sleepiness, apnea-hypopnea index (AHI), oxygen desaturation index, and blood pressure. Although the AHI was also significantly decreased after CPAP treatment in the low-adherence group, blood pressure remained unchanged. CPAP treatment had beneficial effects on both sleep quality and blood pressure only in subjects with OSA and high CPAP adherence who used CPAP for ≥4 h/night for ≥70% of nights monitored. Subjects with low CPAP adherence received beneficial effects on AHI, but not blood pressure. Copyright © 2015 by Daedalus Enterprises.

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)

[Improvement of biventricular heart failure in a case of obstructive sleep apnea syndrome by nasal CPAP therapy].

Science.gov (United States)

Yamamoto, H; Akashiba, T; Minemura, H; Kurashina, K; Yoshizawa, T; Otsuka, K; Horie, T

1993-08-01

A 42-year-old male patient with obstructive sleep apnea syndrome (OSAS) suffering from biventricular heart failure is reported. He had been treated for OSAS with conventional therapy. However, he complained of severe dyspnea in association with extreme weight gain and general edema. Therefore, he was admitted to our department. He weighed 168 kg on admission, and marked edema was observed. Chest film revealed significant dilatation of the cardiac silhouette and pleural effusion. PaO2 was 37 mmHg and PaCO2 was 66 mmHg. Polysomnography showed an apnea index of 58.3 and severe oxygen desaturation during sleep. Right heart catheterization showed elevation of mean pulmonary artery pressure mPAP: 55 mmHg) and pulmonary capillary wedge pressure (Pcwp: 33 mmHg) suggesting biventricular heart failure. Digitalization and diuretic therapy were immediately initiated. In addition, nasal CPAP was applied to this patient during sleep, and sleep apnea and oxygen desaturation were almost completely reversed. Significant diuresis was observed, and blood gas data and sleep disturbance were improved. Fifty-nine days after admission, his weight had decreased to 96 kg, and mPAP and Pcwp decreased to 32 and 23 mmHg, respectively. This case demonstrates that nasal CPA is an effective tool for the treatment severe OSAS patients.

Executive dysfunction in children affected by obstructive sleep apnea syndrome: an observational study

Directory of Open Access Journals (Sweden)

Esposito M

2013-08-01

, all subjects were administered the Pediatric Daytime Sleepiness Scale (PDSS. Results: No significant differences between the two study groups were found for age (P = 0.871, gender (P = 0.704, z-score of body mass index (P = 0.656, total intelligence quotient (P = 0.358, and PDSS scores (P = 0.232. The OSAS children showed a significantly higher rate of total errors (P < 0.001, perseverative errors (P < 0.001, nonperseverative errors (P < 0.001, percentage of total errors (P < 0.001, percentage of perseverative errors (P < 0.001, and percentage of nonperseverative errors (P< 0.001. On the other hand, OSAS children showed a significant reduction in the number of completed categories (P = 0.036, total correct sorts (P = 0.001, and categorizing efficiency (P < 0.001. The Pearson's correlation analysis revealed a significant positive relationship between all error parameters and apnea-hypopnea index, oxygen desaturation index, and percentage of mean desaturation of O2 with a specular negative relationship between the error parameters and the mean oxygen saturation values, such as a significant negative relationship between apnea-hypopnea index, oxygen desaturation index, percent of mean desaturation of O2, and the number of completed categories. Conclusion: Our study identified differences in the executive functioning of children affected by OSAS and is the first to identify a correlation between alteration in respiratory nocturnal parameters and EF that has not yet been reported in developmental age. These findings can be considered as the strength and novelty of the present report in a large pediatric population. Keywords: OSAS, polysomnography, executive functions, sleep, sleepiness, children

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.

Supplemental oxygen for Caesarean section under spinal anaesthesia

African Journals Online (AJOL)

East African Medical Journal ... Setting: The Obafemi Awolowo University Teaching Hospital; a 580 bed hospital situated in Ile-Ife in South-western Nigeria. ... circuit and standard anaesthetic facemask at 4L/min causes relative desaturation.

A functional variant in the stearoyl-CoA desaturase gene promoter enhances fatty acid desaturation in pork.

Directory of Open Access Journals (Sweden)

Joan Estany

Full Text Available There is growing public concern about reducing saturated fat intake. Stearoyl-CoA desaturase (SCD is the lipogenic enzyme responsible for the biosynthesis of oleic acid (18 ∶ 1 by desaturating stearic acid (18 ∶ 0. Here we describe a total of 18 mutations in the promoter and 3' non-coding region of the pig SCD gene and provide evidence that allele T at AY487830:g.2228T>C in the promoter region enhances fat desaturation (the ratio 18 ∶ 1/18 ∶ 0 in muscle increases from 3.78 to 4.43 in opposite homozygotes without affecting fat content (18 ∶ 0+18 ∶ 1, intramuscular fat content, and backfat thickness. No mutations that could affect the functionality of the protein were found in the coding region. First, we proved in a purebred Duroc line that the C-T-A haplotype of the 3 single nucleotide polymorphisms (SNPs (g.2108C>T; g.2228T>C; g.2281A>G of the promoter region was additively associated to enhanced 18 ∶ 1/18 ∶ 0 both in muscle and subcutaneous fat, but not in liver. We show that this association was consistent over a 10-year period of overlapping generations and, in line with these results, that the C-T-A haplotype displayed greater SCD mRNA expression in muscle. The effect of this haplotype was validated both internally, by comparing opposite homozygote siblings, and externally, by using experimental Duroc-based crossbreds. Second, the g.2281A>G and the g.2108C>T SNPs were excluded as causative mutations using new and previously published data, restricting the causality to g.2228T>C SNP, the last source of genetic variation within the haplotype. This mutation is positioned in the core sequence of several putative transcription factor binding sites, so that there are several plausible mechanisms by which allele T enhances 18 ∶ 1/18 ∶ 0 and, consequently, the proportion of monounsaturated to saturated fat.

The Effect of Compression Stockings on Cerebral Desaturation Events in Obese Patients Undergoing Shoulder Arthroscopy in the Beach-Chair Position.

Science.gov (United States)

Tauchen, Alexander J; Salazar, Dane; Barton, Gregory J; Francois, Audrice; Tonino, Pietro; Garbis, Nickolas G; Evans, Douglas

2015-12-01

To determine if the use of thigh-high compression stockings could decrease the incidence of cerebral desaturation events (CDEs) in patients with a body mass index (BMI) of 30 kg/m(2) or greater undergoing shoulder arthroscopy in the beach-chair position (BCP). Between December 2013 and May 2014, 23 patients aged 18 years or older with a BMI of 30 kg/m(2) or greater undergoing shoulder arthroscopy in the BCP were monitored intraoperatively using near-infrared spectroscopy while wearing thigh-high compression stockings. Data obtained on these patients were compared with data from a previous cohort at our institution comprising 24 patients with a BMI of 30 kg/m(2) or greater who underwent elective shoulder arthroscopy in the BCP with the same monitoring but without wearing compression stockings. The incidence of CDEs was identified in each group. The incidence of CDEs in the group with compression stockings was 4% (1 of 23) compared with 18% (7 of 24) in the group without compression stockings (P = .048). There were no statistically significant differences in mean age (53.0 years v 53.3 years, P = .91), mean BMI (34.5 kg/m(2)v 36.2 kg/m(2), P = .21), or various medical comorbidities between the treatment group and control group. There was a significant difference in the operative time between the treatment group (156.6 minutes) and control group (94.1 minutes) (P arthroscopy in the BCP. Level IV, therapeutic case series. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Unsedated Flexible Upper Gastrointestinal Endoscopy: Need for ...

African Journals Online (AJOL)

Background: To determine the incidence of oxygen desaturation and whether routine oxygen monitoring is necessary during unsedated diagnostic flexible upper gastrointestinal endoscopy. Methods: A prospective study involving 54 consecutive in and out patients who had diagnostic upper gastrointestinal endoscopy at ...

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...

Anesthesia for arthroscopic shoulder surgery in the beach chair position: monitoring of cerebral oxygenation using combined bispectral index and near-infrared spectroscopy.

Science.gov (United States)

Kawano, Hiroaki; Matsumoto, Tomomi

2014-10-01

Recent research has shown that cerebrovascular complications following shoulder surgery performed in the beach chair position under general anesthesia arise secondary to cerebral ischemia. Appropriate management of cerebral oxygenation is thus one of the primary goals of anesthetic management during such procedures. The present report describes the case of a 65-year-old male patient, in which both bispectral index (BIS) and near-infrared spectroscopy (NIRS) were used to monitor cerebral oxygenation. During the positioning, we observed an increased suppression ratio (SR) while BIS and regional cerebral oxygen saturation (rSO2) were at adequate level. In view of the difference in blood pressure between the heart and the base of the brain, blood pressure was maintained to ensure adequate cerebral perfusion. Although intraoperative rSO2 was at or around the cut-off point (a 12% relative decrease from baseline), no marked decrease in BIS or further increase in the SR was observed. Monitoring of cerebral perfusion using combined BIS and NIRS optimized anesthetic management during the performance of arthroscopic shoulder surgery in the beach chair position.

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.

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.

A systematic desaturation method for images from the Atmospheric Imaging Assembly in the Solar Dynamics Observatory.

Science.gov (United States)

Torre, Gabriele; Schwartz, Richard; Piana, Michele; Massone, Anna Maria; Benvenuto, Federico

2016-05-01

The fine spatial resolution of the SDO AIA CCD's is often destroyed by the charge in saturated pixels overflowing into a swath of neighboring cells during fast rising solar flares. Automated exposure control can only mitigate this issue to a degree and it has other deleterious effects. Our method addresses the desaturation problem for AIA images as an image reconstruction problem in which the information content of the diffraction fringes, generated by the interaction between the incoming radiation and the hardware of the spacecraft, is exploited to recover the true image intensities within the primary saturated core of the image. This methodology takes advantage of some well defined techniques like cross-correlation and the Expectation Maximization method to invert the direct relation between the diffraction fringes intensities and the true flux intensities. During this talk a complete overview on the structure of the method will be provided, besides some reliability tests obtained by its application against synthetic and real data.

Severe cerebral desaturation during shoulder arthroscopy in the beach-chair position

DEFF Research Database (Denmark)

Dippmann, Christian; Winge, Søren; Nielsen, Henning Bay

2010-01-01

During shoulder arthroscopy in the beach-chair position, cerebral ischemia may be a serious complication because prolonged hypotension may affect regional cerebral oxygen supply. We present the cases of 2 patients in whom a reduction in mean arterial pressure after anesthesia provoked a decrease...... cerebral oxygenation. During surgery in the beach-chair position, hypotension must be avoided, and in all patients regional, cerebral oxygenation should be monitored and optimized....

Desaturation of a clay-stone around a ventilated gallery: numerical modelling of pressures and water contents under various conditions

International Nuclear Information System (INIS)

Ababou, Rachid; Mansouri, Nahla; Bailly, David; Poutrel, Adrien

2012-01-01

(cylindrical drift) is discretized and internalized as a 3D 'macro-porous' body within the computational porous domain. Secondly, the properties of this internal macro-porous body are adjusted in such a way that it will transmit properly the imposed suction (or pressure, or flux, as the case may be) from external to internal boundaries. Here, the suction is imposed on the entry face of the gallery (external boundary), and it is transmitted to the clay/gallery interface (internal boundary). The macro-porous body has a porosity of 100%, a large Darcy permeability compared to the clay-stone, and other special nonlinear and non-isotropic unsaturated properties. Briefly, numerical modelling was conducted with BIGFLOW 3D, an implicit finite volume solver of the saturated/unsaturated Richards equation in mixed form (moisture content 'θ', pressure head 'h'). We used the nonlinear Van Genuchten / Mualem conductivity and water retention curves (K(h); θ(h)) in the unsaturated zone. A specific elastic storativity (S S ) was added in the saturated zone to take into account slight deformation mechanisms in a simplified way (the storativity model does not deal with total stress; it assumes δσ EFF ∼ δp, where p is pore pressure, and σ EFF is Terzaghi's effective stress taken positive when extensional). Finally, the BIGFLOW code can also handle 3D heterogeneity and nonlinear diagonal anisotropy, that is: [Kii(h,x,y,z); θ(h,x,y,z)]. We used these additional capabilities of the code in some of the tests. Figs.1 and 2 show the evolution of desaturation for a 'Type I' test, i.e., with suction imposed on a flat horizontal piece of wall located at the roof of the drift. The drift 'radius' (half-side) is R=2 m. The case shown here is only 'moderately dry': the prescribed suction is ψ=3000 m (∼30 MPa), corresponding to H R =80.74% at T AIR =25 C and P ATM =1 bar (according to Kelvin's law). The imposed desaturation of the porous medium at the drift wall is significant (more than 50% drop

Do We Need Exercise Tests to Detect Gas Exchange Impairment in Fibrotic Idiopathic Interstitial Pneumonias?

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Benoit Wallaert

2012-01-01

Full Text Available In patients with fibrotic idiopathic interstitial pneumonia (f-IIP, the diffusing capacity for carbon monoxide (DLCO has been used to predict abnormal gas exchange in the lung. However, abnormal values for arterial blood gases during exercise are likely to be the most sensitive manifestations of lung disease. The aim of this study was to compare DLCO, resting PaO2, P(A-aO2 at cardiopulmonary exercise testing peak, and oxygen desaturation during a 6-min walk test (6MWT. Results were obtained in 121 patients with idiopathic pulmonary fibrosis (IPF, n=88 and fibrotic nonspecific interstitial pneumonias (NSIP, n=33. All but 3 patients (97.5% had low DLCO values (35 mmHg and 100 (83% demonstrated significant oxygen desaturation during 6MWT (>4%. Interestingly 27 patients had low DLCO and normal P(A-aO2, peak and/or no desaturation during the 6MWT. The 3 patients with normal DLCO also had normal PaO2, normal P(A-aO2, peak, and normal oxygen saturation during 6MWT. Our results demonstrate that in fibrotic IIP, DLCO better defines impairment of pulmonary gas exchange than resting PaO2, exercise P(A-aO2, peak, or 6MWT SpO2.

High index surfaces of Au-nanocrystals supported on one-dimensional MoO3-nanorod as a bi-functional electrocatalyst for ethanol oxidation and oxygen reduction

International Nuclear Information System (INIS)

Karuppasamy, L.; Chen, C.Y.; Anandan, S.; Wu, J.J.

2017-01-01

Highlights: •Synthesis of a new class of Au nanocrystals enclosed with high index surface supported on MoO 3 nanorods by ultrasonic probe method. •The role of supporting materials reduces the loading of Au and acts as a co-catalyst. •The as prepared electrocatalyst exhibits enhanced catalytic activity and stability towards both EOR and ORR. -- Abstract: The design of highly active electrocatalyst for ethanol electrooxidation (EOR) and oxygen reduction reaction (ORR) is of great significance for the improvement of efficient direct ethanol fuel cells (DEFCs). Therefore, creating high index facets nanocrystals with abundant catalytic active sites of stepped atoms is an effective way to enhance the electrocatalytic performance. In this article, we prepared the high index surface structures of Au nanocrystals supported on one-dimensional (1-D) MoO 3 nanorods by using two steps ultrasonic probe irradiation method. The size and physical properties of as electrocatalysts were studied by using field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and x-ray diffraction (XRD) instrumentation. Besides, the catalytic activity of as Au-MoO 3 electrocatalyst was determined by using cyclic voltammetry (CV), chronoamperometric (CA), electrochemical impedance spectroscopy (EIS), CO-stripping, and linear sweep voltammetry-rotating disk electrode (LSV-RDE). As a consequence, the Au-MoO 3 nanocomposites has been considered as an effective electrocatalyst for both ethanol oxidation and oxygen reduction reaction.

Methanol Droplet Combustion in Oxygen-Inert Environments in Microgravity

Science.gov (United States)

Nayagam, Vedha; Dietrich, Daniel L.; Hicks, Michael C.; Williams, Forman A.

2013-01-01

The Flame Extinguishment (FLEX) experiment that is currently underway in the Combustion Integrated Rack facility onboard the International Space Station is aimed at understanding the effects of inert diluents on the flammability of condensed phase fuels. To this end, droplets of various fuels, including alkanes and alcohols, are burned in a quiescent microgravity environment with varying amounts of oxygen and inert diluents to determine the limiting oxygen index (LOI) for these fuels. In this study we report experimental observations of methanol droplets burning in oxygen-nitrogen-carbon dioxide and oxygen-nitrogen-helium gas mixtures at 0.7 and 1 atmospheric pressures. The initial droplet size varied between approximately 1.5 mm and 4 mm to capture both diffusive extinction brought about by insufficient residence time at the flame and radiative extinction caused by excessive heat loss from the flame zone. The ambient oxygen concentration varied from a high value of 30% by volume to as low as 12%, approaching the limiting oxygen index for the fuel. The inert dilution by carbon dioxide and helium varied over a range of 0% to 70% by volume. In these experiments, both freely floated and tethered droplets were ignited using symmetrically opposed hot-wire igniters and the burning histories were recorded onboard using digital cameras, downlinked later to the ground for analysis. The digital images yielded droplet and flame diameters as functions of time and subsequently droplet burning rate, flame standoff ratio, and initial and extinction droplet diameters. Simplified theoretical models correlate the measured burning rate constant and the flame standoff ratio reasonably well. An activation energy asymptotic theory accounting for time-dependent water dissolution or evaporation from the droplet is shown to predict the measured diffusive extinction conditions well. The experiments also show that the limiting oxygen index for methanol in these diluent gases is around 12% to

Dry respirometric index assessment using open and close respirometry

International Nuclear Information System (INIS)

Andreottola, G.; Dallago, L.; Ragazzi, M.

2001-01-01

The aim of this work is to compare two different approaches for the evaluation of the respirometric index of dry biodegradable solid matter. The two used tools have been built in the University of Trent. The AIR-A respirometer (Open Respirometric Index Analyser) used in the experimentation is a pilot device made by a small steel reactor kept at steady temperature. The oxygen analyser and the temperature probe are directly connected to a PC through an acquisition device which allows to follow the evolution of the system. A balance between the amount of the volatile solids, the free volume and the decrease of the oxygen allows to assess the respiration rate. The AIR-C respirometer (Close Respirometric Index Analyser) is constituted by a reactor in which the trend of the internal temperature and the total pressure are constantly measured. A basic solution inside the reactor guarantees the absorption of CO 2 allowing to associate an oxygen consumption to the measure of the total pressure. The reactor is built in order to allow a wide exchange surface between compost and atmosphere, limiting the thickness of the layer of compost in which oxygen must diffuse. A correct balance with the effect induced by the temperature allows to calculate the respirometric index, which is related to the microbic activity only in a portion of the total lasting of the test. The analysis of the generated data and the introduction of some technical modification have allowed to obtain with the two different approaches the same values for the respirometric index [it

End-tidal carbon dioxide monitoring during flexible fiberoptic ...

African Journals Online (AJOL)

In recent years, flexible fiberoptic bronchoscopy (FFB) has been applied for diagnostic and some therapeutic purposes. During FFB and even in the presence of supplemental oxygen, hypoventilation leading to hypoxia and desaturation may occur; this is aggravated by the use of suction. Arterial oxygen saturation is usually ...

Efficacy of Submucosal Sodium Tetradecyl Sulfate in the Soft Palate as a Treatment of the Mild Obstructive Sleep Apnea Syndrome: A Pilot Study

Directory of Open Access Journals (Sweden)

Alberto Labra

2012-01-01

Full Text Available Background. As described by Mair et al. in 2001, snoreplasty, the application of sclerosant agents in the palate is a promising and cheap alternative to treat snoring. We decided to try this kind of therapy for the management of mild sleep apnea. Study Design. Experimental, longitudinal, prospective, nonrandomized, self-controlled pilot study. Methods. 11 patients were included, all of them with a polysomnographic study showing an Apnea-Hypopnea Index (AHI from 5 to 20, and with a Müller maneuver showing only retropalatal collapse. Results. We found significant decrease in the number of apneas hypopneas and oxygen desaturation as well as in the snoring index (<0.05, although no differences were found in the number of arousals. Conclusion. Sclerosant agents might become a relevant part in the treatment of sleep apnea, in very well-selected patients.

High oxygen levels promote peel spotting in banana fruit

NARCIS (Netherlands)

Maneenuam, T.; Ketsa, S.; Doorn, van W.G.

2007-01-01

We studied the effect of high oxygen on early peel spotting in `Sucrier¿ bananas held at 25 °C and 90% RH. Fruit first ripened to colour index 3¿4 (about as yellow as green) and were then held in containers with a continuous gas flow of 18 ± 2 kPa (control) or 90 ± 2 kPa oxygen. High oxygen promoted

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

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

Transnasal humidified rapid insufflation ventilatory exchange for oxygenation of children during apnoea: a prospective randomised controlled trial.

Science.gov (United States)

Riva, T; Pedersen, T H; Seiler, S; Kasper, N; Theiler, L; Greif, R; Kleine-Brueggeney, M

2018-03-01

Transnasal humidified rapid insufflation ventilatory exchange (THRIVE) comprises the administration of heated, humidified, and blended air/oxygen mixtures via nasal cannula at rates of ≥2 litres kg -1  min -1 . The aim of this randomized controlled study was to evaluate the length of the safe apnoea time using THRIVE with two different oxygen concentrations (100% vs 30% oxygen) compared with standard low-flow 100% oxygen administration. Sixty patients, aged 1-6 yr, weighing 10-20 kg, undergoing general anaesthesia for elective surgery, were randomly allocated to receive one of the following oxygen administration methods during apnoea: 1) low-flow 100% oxygen at 0.2 litres kg -1  min -1 ; 2) THRIVE 100% oxygen at 2 litres kg -1  min -1 ; and 3) THRIVE 30% oxygen at 2 litres kg -1  min -1 . Primary outcome was time to desaturation to 95%. Termination criteria included SpO 2 decreased to 95%, transcutaneous CO 2 increased to 65 mmHg, or apnoea time of 10 min. The median (interquartile range) [range] apnoea time was 6.9 (5.7-7.8) [2.8-10.0] min for low-flow 100% oxygen, 7.6 (6.2-9.1) [5.2-10.0] min for THRIVE 100% oxygen, and 3.0 (2.4-3.7) [0.2-5.3] min for THRIVE 30% oxygen. No significant difference was detected between apnoea times with low-flow and THRIVE 100% oxygen administration (P=0.15). THRIVE with 30% oxygen demonstrated significantly shorter apnoea times (Prate of transcutaneous CO 2 increase was 0.57 (0.49-0.63) [0.29-8.92] kPa min -1 without differences between the 3 groups (P=0.25). High-flow 100% oxygen (2 litres kg -1  min -1 ) administered via nasal cannulas did not extend the safe apnoea time for children weighing 10-20 kg compared with low-flow nasal cannula oxygen (0.2 litres kg -1  min -1 ). No ventilatory effect was observed with THRIVE at 2.0 litres kg -1  min -1 . NCT02979067. Copyright © 2017 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.

Tracheobronchomegaly associated tracheomalacia: analysis by sleep study.

Science.gov (United States)

Sundaram, P; Joshi, J M

2004-01-01

Tracheobronchomegaly (TBM) occasionally may progress to extensive tracheomalacia which leads to respiratory failure. Spirometry, dynamic expiratory multidetector computed tomography (CT), bronchoscopy are used to diagnose patients of suspected tracheobronchomalacia. We used the technique of night-time monitoring of respiratory variables to show the presence of respiratory abnormalities during sleep and which was corrected by applying nasal continuous positive airway pressure (CPAP). The study showed the presence of both apnoea and hypopnoeas, which were obstructive in nature with an apnoea-hypopnoea index (AHI) of 11, no snoring and associated oxygen desaturation of 75 per cent. A second overnight study with nasal continuous positive airway pressure at a critical pressure of 8 cm, the AHI decreased to 3 along with no drop in oxygen saturation. This non-invasive technique should be considered as a diagnostic tool in tracheobronchomalacia and to know the outcome of CPAP, surgical or stent therapy in this condition.

Relationship of Hemoglobin to Arterial Oxygen Desaturation during Aeromedical Evacuation

Science.gov (United States)

2015-04-02

2. REPORT TYPE Special Report 3. DATES COVERED (From – To) September 2012 – September 2014 4. TITLE AND SUBTITLE Relationship of Hemoglobin to...pressurized pulsatile, and hydrosurgery debridement methods for removing bacteria from fracture implants. Orthopedics. 2012; 35(7):e1046-e1050. 11. Burns TC

Intermittent nocturnal hypoxia and metabolic risk in obese adolescents with obstructive sleep apnea.

Science.gov (United States)

Narang, Indra; McCrindle, Brian W; Manlhiot, Cedric; Lu, Zihang; Al-Saleh, Suhail; Birken, Catherine S; Hamilton, Jill

2018-01-22

There is conflicting data regarding the independent associations of obstructive sleep apnea (OSA) with metabolic risk in obese youth. Previous studies have not consistently addressed central adiposity, specifically elevated waist to height ratio (WHtR), which is associated with metabolic risk independent of body mass index. The objective of this study was to determine the independent effects of the obstructive apnea-hypopnea index (OAHI) and associated indices of nocturnal hypoxia on metabolic function in obese youth after adjusting for WHtR. Subjects had standardized anthropometric measurements. Fasting blood included insulin, glucose, glycated hemoglobin, alanine transferase, and aspartate transaminase. Insulin resistance was quantified with the homeostatic model assessment. Overnight polysomnography determined the OAHI and nocturnal oxygenation indices. Of the 75 recruited subjects, 23% were diagnosed with OSA. Adjusting for age, gender, and WHtR in multivariable linear regression models, a higher oxygen desaturation index was associated with a higher fasting insulin (coefficient [standard error] = 48.076 [11.255], p Intermittent nocturnal hypoxia rather than the OAHI was associated with metabolic risk in obese youth after adjusting for WHtR. Measures of abdominal adiposity such as WHtR should be considered in future studies that evaluate the impact of OSA on metabolic health.

Hyperbaric Oxygen Therapy and Oxygen Compatibility of Skin and Wound Care Products.

Science.gov (United States)

Bernatchez, Stéphanie F; Tucker, Joseph; Chiffoleau, Gwenael

2017-11-01

Objective: Use test methods to assess the oxygen compatibility of various wound care products. Approach: There are currently no standard test methods specifically for evaluating the oxygen compatibility and safety of materials under hyperbaric oxygen (HBO) conditions. However, tests such as the oxygen index (OI), oxygen exposure (OE), and autogenous ignition temperature (AIT) can provide useful information. Results: The OI test measures the minimum oxygen concentration that will support candle-like burning, and it was used to test 44 materials. All but two exhibited an OI equal to or greater (safer) than a control material commonly used in HBO. The OE test exposes each material to an oxygen-enriched atmosphere (>99.5% oxygen) to monitor temperature and pressure for an extended duration. The results of the OE testing indicated that none of the 44 articles tested with this method self-ignited within the 60°C, 3 atm pressurized oxygen atmosphere. The AIT test exposes materials to a rapid ramp up in temperature in HBO conditions at 3 atm until ignition occurs. Ten wound care materials and seven materials usually avoided in HBO chambers were tested. The AIT ranged from 138°C to 384°C for wound care products and from 146°C to 420°C for the other materials. Innovation: This work provides useful data and recommendations to help develop a new standard approach for evaluating the HBO compatibility of wound care products to ensure safety for patients and clinicians. Conclusion: The development of an additional test to measure the risk of electrostatic discharge of materials in HBO conditions is needed.

Late postoperative episodic and constant hypoxaemia and associated ECG abnormalities

DEFF Research Database (Denmark)

Rosenberg, J; Rasmussen, Verner; von Jessen, F

1990-01-01

heart rate increased 16 beat min-1 (P less than 0.001) and mean oxygen saturation (SaO2) decreased 2.6% (P less than 0.001) after operation. Episodic oxygen desaturation to less than 80% occurred in four patients before operation, but in 13 patients after operation (P less than 0.05). ECG abnormalities...

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.

[Role of erythrocyte cytoplasmic structures in changes in the affinity of haemoglobin for oxygen].

Science.gov (United States)

Bryzgalova, N Iu; Brazhe, N A; Iusipovich, A U; Maksimov, G V; Rubin, A B

2009-01-01

Changes in the refractive index of the cytoplasm and the affinity of haemoporphyrin of erythrocyte haemoglobin to oxygen (pH, 2,3-diphosphoglycerate) have been investigated using laser interference microscopy and Raman spectroscopy. It has been established that a decrease in pH and an increase in the content of 2,3-diphosphoglycerate are accompanied by changes in both the form of the cell and the refractive index of the cytoplasm and the affinity of haemoporphyrin of hemoglobin to oxygen. It has been shown that as pH is reduced, the capacity of haemoporphyrin for binding oxygen decreases and as the concentration of 2,3-diphosphoglycerate is increased, the ability of haemoporphyrin for oxygen reabsorption increases.

Studies on the rheology and oxygen mass transfer in the clavulanic acid production by Streptomyces clavuligerus

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E. R. Gouveia

2000-12-01

Full Text Available In the present work rheological characteristics and volumetric oxygen transfer coefficient (kLa were investigated during batch cultivations of Streptomyces clavuligerus NRRL 3585 for production of clavulanic acid. The experimental rheological data could be adequately described in terms of the power law model and logistic equation. Significant changes in the rheological parameters consistency index (K and flow behavior index (n were observed with the fermentation evolution. Interesting correlations between the consistency index (K/biomass concentration (C X and the flow behavior index (n/biomass concentration were proposed. Volumetric oxygen mass transfer coefficient (kLa was determined by the gas balance method. Classical correlation relating the volumetric oxygen mass transfer coefficient to the operating conditions, physical and to transport properties, including apparent viscosity (muap, could be applied to the experimental results.

How does serum brain natriuretic peptide level change under nasal ...

African Journals Online (AJOL)

2016-08-30

related breathing disorder that occurs in about 4Б7% of the general adult population (1). It is characterized by recurrent episodes of complete or partial upper airway obstruction during sleep, resulting in oxygen desaturation, sleep.

Increased Ventricular Premature Contraction Frequency During REM Sleep in Patients with Coronary Artery Disease and Obstructive Sleep Apnea

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Mari A. Watanabe

2008-11-01

Full Text Available Background Patients with obstructive sleep apnea are reported to have a peak of sudden cardiac death at night, in contrast to patients without apnea whose peak is in the morning. We hypothesized that ventricular premature contraction (VPC frequency would correlate with measures of apnea and sympathetic activity.Methods Electrocardiograms from a sleep study of 125 patients with coronary artery disease were evaluated. Patients were categorized by apnea-hypopnea index (AHI into Moderate (AHI 15 apnea groups. Sleep stages studied were Wake, S1, S2, S34, and rapid eye movement (REM. Parameters of a potent autonomically-based risk predictor for sudden cardiac death called heart rate turbulence were calculated.Results There were 74 Moderate and 51 Severe obstructive sleep apnea patients. VPC frequency was affected significantly by sleep stage (Wake, S2 and REM, F=5.8, p<.005 and by AHI (F=8.7, p<.005. In Severe apnea patients, VPC frequency was higher in REM than in Wake (p=.011. In contrast, patients with Moderate apnea had fewer VPCs and exhibited no sleep stage dependence (p=.19. Oxygen desaturation duration per apnea episode correlated positively with AHI (r2=.71, p<.0001, and was longer in REM than in non-REM (p<.0001. The heart rate turbulence parameter TS correlated negatively with oxygen desaturation duration in REM (r2=.06, p=.014.Conclusions Higher VPC frequency coupled with higher sympathetic activity caused by longer apnea episodes in REM sleep may be one reason for increased nocturnal death in apneic patients.

The real limits to marine life: a further critique of the Respiration Index

Science.gov (United States)

Seibel, B. A.; Childress, J. J.

2013-05-01

The recently proposed "Respiration Index" (RI = log PO2/PCO2) suggests that aerobic metabolism is limited by the ratio of reactants (oxygen) to products (carbon dioxide) according to the thermodynamics of cellular respiration. Here, we demonstrate further that, because of the large standard free energy change for organic carbon oxidation (ΔG° = -686 kcal mol-1), carbon dioxide can never reach concentrations that would limit the thermodynamics of this reaction. A PCO2 to PO2 ratio of 10503 would be required to reach equilibrium (equilibrium constant, Keq = 10503), where ΔG = 0. Thus, a Respiration Index of -503 would be the real thermodynamic limit to aerobic life. Such a Respiration Index is never reached, either in the cell or in the environment. Moreover, cellular respiration and oxygen provision are kinetically controlled such that, within limits, environmental oxygen and CO2 concentrations have little to do with intracellular concentrations. The RI is fundamentally different from the aragonite saturation state, a thermodynamic index used to quantify the potential effect of CO2 on calcification rates, because of its failure to incorporate the equilibrium constant of the reaction. Not only is the RI invalid, but its use leads to incorrect and misleading predictions of the threat of changing oxygen and carbon dioxide to marine life. We provide a physiological framework that identifies oxygen thresholds and allows for synergistic effects of ocean acidification and global warming.

The real limits to marine life: a further critique of the Respiration Index

Directory of Open Access Journals (Sweden)

B. A. Seibel

2013-05-01

Full Text Available The recently proposed "Respiration Index" (RI = log PO2/PCO2 suggests that aerobic metabolism is limited by the ratio of reactants (oxygen to products (carbon dioxide according to the thermodynamics of cellular respiration. Here, we demonstrate further that, because of the large standard free energy change for organic carbon oxidation (ΔG° = −686 kcal mol−1, carbon dioxide can never reach concentrations that would limit the thermodynamics of this reaction. A PCO2 to PO2 ratio of 10503 would be required to reach equilibrium (equilibrium constant, Keq = 10503, where ΔG = 0. Thus, a Respiration Index of −503 would be the real thermodynamic limit to aerobic life. Such a Respiration Index is never reached, either in the cell or in the environment. Moreover, cellular respiration and oxygen provision are kinetically controlled such that, within limits, environmental oxygen and CO2 concentrations have little to do with intracellular concentrations. The RI is fundamentally different from the aragonite saturation state, a thermodynamic index used to quantify the potential effect of CO2 on calcification rates, because of its failure to incorporate the equilibrium constant of the reaction. Not only is the RI invalid, but its use leads to incorrect and misleading predictions of the threat of changing oxygen and carbon dioxide to marine life. We provide a physiological framework that identifies oxygen thresholds and allows for synergistic effects of ocean acidification and global warming.

Pulmonary venous flow index as a predictor of pulmonary vascular resistance variability in congenital heart disease with increased pulmonary flow: a comparative study before and after oxygen inhalation.

Science.gov (United States)

Rivera, Ivan Romero; Mendonça, Maria Alayde; Andrade, José Lázaro; Moises, Valdir; Campos, Orlando; Silva, Célia Camelo; Carvalho, Antonio Carlos

2013-09-01

There is no definitive and reliable echocardiographic method for estimating the pulmonary vascular resistance (PVR) to differentiate persistent vascular disease from dynamic pulmonary hypertension. The aim of this study was to analyze the relationship between the pulmonary venous blood flow velocity-time integral (VTIpv) and PVR. Eighteen patients (10 females; 4 months to 22 years of age) with congenital heart disease and left to right shunt were studied. They underwent complete cardiac catheterization, including measurements of the PVR and Qp:Qs ratio, before and after 100% oxygen inhalation. Simultaneous left inferior pulmonary venous flow VTIpv was obtained by Doppler echocardiography. The PVR decreased significantly from 5.0 ± 2.6 W to 2.8 ± 2.2 W (P = 0.0001) with a significant increase in the Qp:Qs ratio, from 3.2 ± 1.4 to 4.9 ± 2.4 (P = 0.0008), and the VTIpv increased significantly from 22.6 ± 4.7 cm to 28.1 ± 6.2 cm (P = 0.0002) after 100% oxygen inhalation. VTIpv correlated well with the PVR and Qp:Qs ratio (r = -0.74 and 0.72, respectively). Diagnostic indexes indicated a sensitivity of 86%, specificity of 75%, accuracy of 83%, a positive predictive value of 92% and a negative predictive value of 60%. The VTIpv correlated well with the PVR. The measurement of this index before and after oxygen inhalation may become a useful noninvasive test for differentiating persistent vascular disease from dynamic and flow-related pulmonary hypertension. © 2013, Wiley Periodicals, Inc.

Chemisorption of oxygen and subsequent reactions on low index surfaces of β-Mo₂C

DEFF Research Database (Denmark)

Shi, Xue Rong; Wang, Shengguang; Wang, Jianguo

2016-01-01

to the carbon vacancy were identified. We examined the effect of oxygen coverage on the morphology of β-Mo2C by plotting the equilibrium crystal shape. Thermodynamic effect of temperature and reactant or product pressure on the CO/CO2 desorption were investigated. The CO/CO2 desorption is more favorable...... at the saturated oxygen coverage than the low oxygen coverage thermodynamically. The subsequent oxygen diffusion to the carbon vacancy after CO/CO2 desorption may happen depending on the surfaces and oxygen coverage....

Reduced muscle activation during exercise related to brain oxygenation and metabolism in humans

DEFF Research Database (Denmark)

Rasmussen, Peter; Nielsen, Jannie; Overgaard, M

2010-01-01

Maximal exercise may be limited by central fatigue defined as an inability of the central nervous system to fully recruit the involved muscles. This study evaluated whether a reduction in the cerebral oxygen-to-carbohydrate index (OCI) and in the cerebral mitochondrial oxygen tension relate to th...... indicating that reduced cerebral oxygenation may play a role in the development of central fatigue and may be an exercise capacity limiting factor.......Maximal exercise may be limited by central fatigue defined as an inability of the central nervous system to fully recruit the involved muscles. This study evaluated whether a reduction in the cerebral oxygen-to-carbohydrate index (OCI) and in the cerebral mitochondrial oxygen tension relate...... of perceived exertion (RPE), arm maximal voluntary force (MVC), and voluntary activation of elbow flexor muscles assessed with transcranial magnetic stimulation. Low intensity exercise did not produce any indication of central fatigue or marked cerebral metabolic deviations. Exercise in hypoxia (0.10) reduced...

Reproducibility of proximal and distal transcutaneous oxygen pressure measurements during exercise in stage 2 arterial claudication.

Science.gov (United States)

Bouyé, P; Picquet, J; Jaquinandi, V; Enon, B; Leftheriotis, G; Saumet, J-L; Abraham, P

2004-06-01

Although transcutaneous oxygen pressure measurements (tcpO2) are largely used in the investigation of vascular patients, its reproducibility is still debated. Indeed an unpredictable gradient exists between arterial and transcutaneous oxygen pressure. We hypothesised that indices taking into account changes over time and independent of absolute starting values would be more reproducible than other indices. comparative test-retest procedure (1 to 13 days between tests). institutional practice, ambulatory care. 15 subjects with stage 2 claudication. tcpO2 recordings at rest and at exercise during the 2 treadmill tests. calculation of the Delta-from-rest of oxygen pressure index (limb tcpO2 changes minus chest tcpO2 changes), of the resting - or minimal values attained during exercise - of absolute tcpO2 and of the regional perfusion index (regional perfusion index: ration of limb to chest). Both absolute tcpO2 and regional perfusion index at rest showed low reproducibility. During exercise the best reproducibility was attained through Delta-from-rest of oxygen pressure index calculation. Equations from the linear regression analysis (test 2 versus test 1) were 0.88 x -4.2 (r(2)=0.82) at the buttock level and 0.82 x -3.8 (r(2)=0.80) at the calf level. TcpO2 measurement on the calf or buttock during exercise, is a reproducible measurement in patients with vascular claudication, specifically when corrected for exercise-induced systemic pO2 changes trough Delta-from-rest of oxygen pressure calculation.

α4-integrin receptor desaturation and disease activity return after natalizumab cessation.

Science.gov (United States)

Derfuss, Tobias; Kovarik, John M; Kappos, Ludwig; Savelieva, Marina; Chhabra, Richa; Thakur, Avinash; Zhang, Ying; Wiendl, Heinz; Tomic, Davorka

2017-09-01

To describe the time course of α4-integrin receptor desaturation and disease activity return in patients with relapsing-remitting MS who discontinued natalizumab and to investigate baseline and on-study predictors for the recurrence of disease activity. In the course of TOFINGO, a 32-week, patient- and rater-blinded multicenter, parallel-group study, we performed MRI, counted relapses, and measured α4-integrin receptor occupancy (RO) at baseline and 8, 12, 16, 20, and 24 weeks. The relationship between RO and total number of new T1 gadolinium-enhancing (Gd+) lesions was modeled using Poisson linear regression. Patients (N = 142) were randomized (1:1:1) to 8-, 12-, or 16-week washout (WO) groups. At randomization, the median RO in the 8-, 12-, and 16-week WO groups was 94.5%, 92.4%, and 90.9%, which declined to 79.8%, 30.7%, and 8.7% after 8, 12, and 16 weeks of WO, respectively. The percentage of patients with new T1 Gd+ lesions increased with longer WO period before commencing fingolimod: 2.1% (8 weeks), 9.1% (12 weeks), and 50.0% (16 weeks). Overall, 71% of patients with first relapse between weeks 6 and 18 had RO values below the time-matched population median. Higher T2 lesion volume (LV) at baseline predicted a higher number of new T1 Gd+ lesions. A faster decline in natalizumab RO, longer WO period, and higher T2 LV at baseline were associated with an increased risk for return of inflammatory disease activity. These results provide a mechanistic rationale and, together with the main outcomes of the TOFINGO study, support initiation of fingolimod within 8 weeks of natalizumab discontinuation. NCT01499667.

Objectively measured sleep and β-amyloid burden in older adults: A pilot study

Directory of Open Access Journals (Sweden)

Adam P Spira

2014-08-01

Full Text Available Background/aims: Although disturbed sleep is associated with cognitive deficits, the association between sleep disturbance and Alzheimer’s disease pathology is unclear. In this pilot study, we examined the extent to which sleep duration, sleep quality, and sleep-disordered breathing are associated with β-amyloid (Aβ deposition in the brains of living humans. Methods: We studied 13 older adults (8 with normal cognition and 5 with mild cognitive impairment. Participants completed neuropsychological testing, polysomnography, and Aβ imaging with [11C]-Pittsburgh compound B. Results: Among participants with mild cognitive impairment, higher apnea–hypopnea index and oxygen desaturation index were associated with greater Aβ deposition, globally and regionally in the precuneus. There were no significant associations between sleep-disordered breathing and Aβ deposition among cognitively normal participants. There were no significant associations between sleep duration or sleep fragmentation and Aβ deposition. Conclusion: These preliminary results suggest that among older adults with mild cognitive impairment, greater sleep-disordered breathing severity is associated with greater Aβ deposition.

Antioxidant Carbocysteine Treatment in Obstructive Sleep Apnea Syndrome: A Randomized Clinical Trial.

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Kang Wu

Full Text Available This study aimed to examine the effects of carbocysteine in OSAS patients.A total of 40 patients with moderate to severe obstructive sleep apnea syndrome (OSAS were randomly divided into two groups. One group was treated with 1500 mg carbocysteine daily, and the other was treated with continuous positive airway pressure (CPAP at night. Before treatment and after 6 weeks of treatment, all patients underwent polysomnography and completed questionnaires. Treatment compliance was compared between the two groups. Plasma was collected for various biochemical analyses. Endothelial function was assessed with ultrasound in the carbocysteine group.The proportion of patients who fulfilled the criteria for good compliance was higher in the carbocysteine group (n = 17 than in the CPAP group (n = 11; 100% vs. 64.7%. Compared with baseline values, the carbocysteine group showed significant improvement in their Epworth Sleepiness Scale score (10.18 ± 4.28 vs. 6.82 ± 3.66; P ≤ 0.01, apnea-hypopnea index (55.34 ± 25.03 vs. 47.56 ± 27.32; P ≤ 0.01, time and percentage of 90% oxygen desaturation (12.66 (2.81; 50.01 vs. 8.9 (1.41; 39.71; P ≤ 0.01, and lowest oxygen saturation level (65.88 ± 14.86 vs. 70.41 ± 14.34; P ≤ 0.01. Similar changes were also observed in the CPAP group. The CPAP group also showed a decreased oxygen desaturation index and a significant increase in the mean oxygen saturation after treatment, but these increases were not observed in the carbocysteine group. Snoring volume parameters, such as the power spectral density, were significantly reduced in both groups after the treatments. The plasma malondialdehyde level decreased and the superoxide dismutase and nitric oxide levels increased in both groups. The endothelin-1 level decreased in the CPAP group but did not significantly change in the carbocysteine group. Ultrasonography showed that the intima-media thickness decreased (0.71 ± 0.15 vs. 0.66 ± 0.15; P ≤ 0.05 but that flow

Study on combustion characteristics of dimethyl ether under the moderate or intense low-oxygen dilution condition

International Nuclear Information System (INIS)

Kang, Yinhu; Lu, Tianfeng; Lu, Xiaofeng; Wang, Quanhai; Huang, Xiaomei; Peng, Shini; Yang, Dong; Ji, Xuanyu; Song, Yangfan

2016-01-01

hydroxyl radical concentration inside the reaction zone significantly. Emission index of carbon monoxide increased at lower co-flow temperature or oxygen mole fraction; and it was more sensitive to the variation in co-flow oxygen mole fraction. Additionally, the dominant formation pathways of nitrogen oxide in the dimethyl ether-moderate or intense low-oxygen dilution flame were clarified. The contribution of the thermal pathway was fairly unimportant. Emission index of nitrogen oxide increased as co-flow temperature or oxygen mole fraction was increased. The ratio of nitrogen dioxide emission index to nitrogen oxide emission index decreased with the increment in co-flow temperature or oxygen mole fraction.

Ketamine has no effect on oxygenation indices following elective coronary artery bypass grafting under cardiopulmonary bypass

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Parthasarathi Gayatri

2011-01-01

Full Text Available Cardiopulmonary bypass is known to elicit systemic inflammatory response syndrome and organ dysfunction. This can result in pulmonary dysfunction and deterioration of oxygenation after cardiac surgery and cardiopulmonary bypass. Previous studies have reported varying results on anti-inflammatory strategies and oxygenation after cardiopulmonary bypass. Ketamine administered as a single dose at induction has been shown to reduce the pro-inflammatory serum markers in patients undergoing cardiopulmonary bypass. Therefore we investigated if ketamine can result in better oxygenation in these patients. This was a prospective randomized blinded study. Eighty consecutive adult patients undergoing elective coronary artery bypass grafting under cardiopulmonary bypass were included in the study. Patients were divided into two groups. Patients in ketamine group received 1mg/kg of ketamine intravenously at induction of anesthesia. Control group patients received an equal volume of saline. All patients received standard anesthesia, operative and postoperative care.Paired t test and independent sample t test were used to compare the inter-group and between group oxygenation indices respectively. Oxygenation index and duration of ventilation were analyzed. Deterioration of oxygenation index was noted in both the groups after cardiopulmonary bypass. However, there was no significant difference in the oxygenation index at various time points after cardiopulmonary bypass or the duration of ventilation between the two groups. This study shows that the administered as a single dose at induction does not result in better oxygenation after cardiopulmonary bypass.

Evaluation of Candidate Measures for Home-Based Screening of Sleep Disordered Breathing in Taiwanese Bus Drivers

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Hua Ting

2014-05-01

Full Text Available Background: Sleepiness-at-the-wheel has been identified as a major cause of highway accidents. The aim of our study is identifying the candidate measures for home-based screening of sleep disordered breathing in Taiwanese bus drivers, instead of polysomnography. Methods: Overnight polysomnography accompanied with simultaneous measurements of alternative screening devices (pulse oximetry, ApneaLink, and Actigraphy, heart rate variability, wake-up systolic blood pressure and questionnaires were completed by 151 eligible participants who were long-haul bus drivers with a duty period of more than 12 h a day and duty shifting. Results: 63.6% of professional bus drivers were diagnosed as having sleep disordered breathing and had a higher body mass index, neck circumference, systolic blood pressure, arousal index and desaturation index than those professional bus drivers without evidence of sleep disordered breathing. Simple home-based candidate measures: (1 Pulse oximetry, oxygen-desaturation indices by ≥3% and 4% (r = 0.87~0.92; (2 Pulse oximetry, pulse-rising indices by ≥7% and 8% from a baseline (r = 0.61~0.89; and (3 ApneaLink airflow detection, apnea-hypopnea indices (r = 0.70~0.70, based on recording-time or Actigraphy-corrected total sleep time were all significantly correlated with, and had high agreement with, corresponding polysomnographic apnea-hypopnea indices [(1 94.5%~96.6%, (2 93.8%~97.2%, (3 91.1%~91.3%, respectively]. Conversely, no validities of SDB screening were found in the multi-variables apnea prediction questionnaire, Epworth Sleepiness Scale, night-sleep heart rate variability, wake-up systolic blood pressure and anthropometric variables. Conclusions: The indices of pulse oximetry and apnea flow detection are eligible criteria for home-based screening of sleep disordered breathing, specifically for professional drivers.

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.

Characterization of sleep breathing pattern in patients with type 2 diabetes: sweet sleep study.

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Albert Lecube

Full Text Available Although sleep apnea-hypopnea syndrome (SAHS is highly prevalent in patients with type 2 diabetes (T2D, it is unknown whether or not subjects with and without T2D share the same sleep breathing pattern.A cross-sectional study in patients with SAHS according to the presence (n = 132 or not (n = 264 of T2D. Both groups were matched by age, gender, BMI, and waist and neck circumferences. A subgroup of 125 subjects was also matched by AHI. The exclusion criteria included chronic respiratory disease, alcohol abuse, use of sedatives, and heart failure. A higher apnea hypopnea index (AHI was observed in T2D patients [32.2 (10.2-114.0 vs. 25.6 (10.2-123.4 events/hours; p = 0.002. When sleep events were evaluated separately, patients with T2D showed a significant increase in apnea events [8.4 (0.1-87.7 vs. 6.3 (0.0-105.6 e/h; p = 0.044, as well as a two-fold increase in the percentage of time spent with oxygen saturation <90% [15.7 (0.0-97.0 vs. 7.9 (0.0-95.6 %; <0.001], higher rates of oxygen desaturation events, and also higher daily sleepiness [7.0 (0.0-21.0 vs. 5.0 (0.0-21.0; p = 0.006] than subjects without T2D. Significant positive correlations between fasting plasma glucose and AHI, the apnea events, and CT90 were observed. Finally, multiple linear regression analyses showed that T2D was independently associated with AHI (R2 = 0.217, the apnea index (R2 = 0.194, CT90 (R2 = 0.222, and desaturation events.T2D patients present a different pattern of sleep breathing than subject without diabetes. The most important differences are the severity of hypoxemia and the number of apneas whereas the incidence of hypopnea episodes is similar.

Whole Genome DNA Methylation Analysis of Obstructive Sleep Apnea: IL1R2, NPR2, AR, SP140 Methylation and Clinical Phenotype.

Science.gov (United States)

Chen, Yung-Che; Chen, Ting-Wen; Su, Mao-Chang; Chen, Chung-Jen; Chen, Kuang-Den; Liou, Chia-Wei; Tang, Petrus; Wang, Ting-Ya; Chang, Jen-Chieh; Wang, Chin-Chou; Lin, Hsin-Ching; Chin, Chien-Hung; Huang, Kuo-Tung; Lin, Meng-Chih; Hsiao, Chang-Chun

2016-04-01

We hypothesized that DNA methylation patterns may contribute to disease severity or the development of hypertension and excessive daytime sleepiness (EDS) in patients with obstructive sleep apnea (OSA). Illumina's (San Diego, CA, USA) DNA methylation 27-K assay was used to identify differentially methylated loci (DML). DNA methylation levels were validated by pyrosequencing. A discovery cohort of 15 patients with OSA and 6 healthy subjects, and a validation cohort of 72 patients with sleep disordered breathing (SDB). Microarray analysis identified 636 DMLs in patients with OSA versus healthy subjects, and 327 DMLs in patients with OSA and hypertension versus those without hypertension. In the validation cohort, no significant difference in DNA methylation levels of six selected genes was found between the primary snoring subjects and OSA patients (primary outcome). However, a secondary outcome analysis showed that interleukin-1 receptor 2 (IL1R2) promoter methylation (-114 cytosine followed by guanine dinucleotide sequence [CpG] site) was decreased and IL1R2 protein levels were increased in the patients with SDB with an oxygen desaturation index > 30. Androgen receptor (AR) promoter methylation (-531 CpG site) and AR protein levels were both increased in the patients with SDB with an oxygen desaturation index > 30. Natriuretic peptide receptor 2 (NPR2) promoter methylation (-608/-618 CpG sites) were decreased, whereas levels of both NPR2 and serum C type natriuretic peptide protein were increased in the SDB patients with EDS. Speckled protein 140 (SP140) promoter methylation (-194 CpG site) was increased, and SP140 protein levels were decreased in the patients with SDB and EDS. IL1R2 hypomethylation and AR hypermethylation may constitute an important determinant of disease severity, whereas NPR2 hypomethylation and SP140 hypermethylation may provide a biomarker for vulnerability to EDS in OSA. A commentary on this article appears in this issue on page 723. © 2016

Current sedation and monitoring practice for colonoscopy: an International Observational Study (EPAGE)

DEFF Research Database (Denmark)

Froehlich, F; Harris, JK; Wietlisbach, V

2006-01-01

centers. Oxygen desaturation (LT /= 85 %) occurred in 5 % of patients, of whom 80 % were moderately sedated. On average, three staff members were involved in procedures. An anesthesiologist was present during 27 % of colonoscopies, and during 85 % of colonoscopies using deep sedation. CONCLUSIONS...

Oxygen supply in aquatic ectotherms: partial pressure and solubility together explain biodiversity and size patterns.

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Verberk, Wilco C E P; Bilton, David T; Calosi, Piero; Spicer, John I

2011-08-01

Aquatic ectotherms face the continuous challenge of capturing sufficient oxygen from their environment as the diffusion rate of oxygen in water is 3 x 10(5) times lower than in air. Despite the recognized importance of oxygen in shaping aquatic communities, consensus on what drives environmental oxygen availability is lacking. Physiologists emphasize oxygen partial pressure, while ecologists emphasize oxygen solubility, traditionally expressing oxygen in terms of concentrations. To resolve the question of whether partial pressure or solubility limits oxygen supply in nature, we return to first principles and derive an index of oxygen supply from Fick's classic first law of diffusion. This oxygen supply index (OSI) incorporates both partial pressure and solubility. Our OSI successfully explains published patterns in body size and species across environmental clines linked to differences in oxygen partial pressure (altitude, organic pollution) or oxygen solubility (temperature and salinity). Moreover, the OSI was more accurately and consistently related to these ecological patterns than other measures of oxygen (oxygen saturation, dissolved oxygen concentration, biochemical oxygen demand concentrations) and similarly outperformed temperature and altitude, which covaried with these environmental clines. Intriguingly, by incorporating gas diffusion rates, it becomes clear that actually more oxygen is available to an organism in warmer habitats where lower oxygen concentrations would suggest the reverse. Under our model, the observed reductions in aerobic performance in warmer habitats do not arise from lower oxygen concentrations, but instead through organismal oxygen demand exceeding supply. This reappraisal of how organismal thermal physiology and oxygen demands together shape aerobic performance in aquatic ectotherms and the new insight of how these components change with temperature have broad implications for predicting the responses of aquatic communities to

Water quality index for Al-Gharraf River, southern Iraq

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Salam Hussein Ewaid

2017-06-01

Full Text Available The Water Quality Index has been developed mathematically to evaluate the water quality of Al-Gharraf River, the main branch of the Tigris River in the south of Iraq. Water samples were collected monthly from five sampling stations during 2015–2016, and 11 parameters were analyzed: biological oxygen demand, total dissolved solids, the concentration of hydrogen ions, dissolved oxygen, turbidity, phosphates, nitrates, chlorides, as well as turbidity, total hardness, electrical conductivity and alkalinity. The index classified the river water, without including turbidity as a parameter, as good for drinking at the first station, poor at stations 2, 3, 4 and very poor at station 5. When turbidity was included, the index classified the river water as unsuitable for drinking purposes in the entire river. The study highlights the importance of applying the water quality indices which indicate the total effect of the ecological factors on surface water quality and which give a simple interpretation of the monitoring data to help local people in improving water quality.

Estimation of maximal oxygen uptake without exercise testing in Korean healthy adult workers.

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Jang, Tae-Won; Park, Shin-Goo; Kim, Hyoung-Ryoul; Kim, Jung-Man; Hong, Young-Seoub; Kim, Byoung-Gwon

2012-08-01

Maximal oxygen uptake is generally accepted as the most valid and reliable index of cardiorespiratory fitness and functional aerobic capacity. The exercise test for measuring maximal oxygen uptake is unsuitable for screening tests in public heath examinations, because of the potential risks of exercise exertion and time demands. We designed this study to determine whether work-related physical activity is a potential predictor of maximal oxygen uptake, and to develop a maximal oxygen uptake equation using a non-exercise regression model for the cardiorespiratory fitness test in Korean adult workers. Study subjects were adult workers of small-sized companies in Korea. Subjects with history of disease such as hypertension, diabetes, asthma and angina were excluded. In total, 217 adult subjects (113 men of 21-55 years old and 104 women of 20-64 years old) were included. Self-report questionnaire survey was conducted on study subjects, and maximal oxygen uptake of each subject was measured with the exercise test. The statistical analysis was carried out to develop an equation for estimating maximal oxygen uptake. The predictors for estimating maximal oxygen uptake included age, gender, body mass index, smoking, leisure-time physical activity and the factors representing work-related physical activity. The work-related physical activity was identified to be a predictor of maximal oxygen uptake. Moreover, the equation showed high validity according to the statistical analysis. The equation for estimating maximal oxygen uptake developed in the present study could be used as a screening test for assessing cardiorespiratory fitness in Korean adult workers.

Neonatal and pediatric extracorporeal membrane oxygenation in developing Latin American countries

OpenAIRE

Kattan, Javier; González, Álvaro; Castillo, Andrés; Caneo, Luiz Fernando

2017-01-01

Objective: To review the principles of neonatal‐pediatric extracorporeal membrane oxygenation therapy, prognosis, and its establishment in limited resource‐limited countries in Latino America. Sources: The PubMed database was explored from 1985 up to the present, selecting from highly‐indexed and leading Latin American journals, and Extracorporeal Life Support Organization reports. Summary of the findings: Extracorporeal membrane oxygenation provides “time” for pulmonary and cardiac res...

Oxygen consumption rates by different oenological tannins in a model wine solution.

Science.gov (United States)

Pascual, Olga; Vignault, Adeline; Gombau, Jordi; Navarro, Maria; Gómez-Alonso, Sergio; García-Romero, Esteban; Canals, Joan Miquel; Hermosín-Gutíerrez, Isidro; Teissedre, Pierre-Louis; Zamora, Fernando

2017-11-01

The kinetics of oxygen consumption by different oenological tannins were measured in a model wine solution using the non-invasive method based on luminiscence. The results indicate that the oxygen consumption rate follows second-order kinetics depending on tannin and oxygen concentrations. They also confirm that the oxygen consumption rate is influenced by temperature in accordance with Arrhenius law. The indications are that ellagitannins are the fastest oxygen consumers of the different oenological tannins, followed in decreasing order by quebracho tannins, skin tannins, seed tannins and finally gallotannins. This methodology can therefore be proposed as an index for determining the effectiveness of different commercial tannins in protecting wines against oxidation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Are baby hammocks safe for sleeping babies? A randomised controlled trial.

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Chiu, Karen; Tonkin, Shirley L; Gunn, Alistair J; McIntosh, Christine C

2014-07-01

Two reports of infants found dead after sleeping in baby hammocks have raised international concern about the safety of infant hammocks. We therefore tested whether hammock sleep affected oxygenation in infants, when they were at an age of high risk of sudden, unexpected infant death. Healthy, full-term 4- to 8-week-old infants were randomised to sleep either in a commercially available hammock (n = 14) or a standard bassinet (n = 9), and sleep state, oxygen desaturation (a fall in peripheral haemoglobin oxygen saturation (SpO2 ) ≥ 4%, for ≥ 4 sec from baseline to nadir), apnoea and hypopnoea, and mean SpO2 were analysed. There was no significant difference in mean SpO2 (both 98.5%) or rate of oxygen desaturation events between the hammock and the bassinet cot (mean ± SD, 24 ± 20 vs. 28 ± 23 events per hour), but infants slept less in the hammock (59 ± 31 vs. 81 ± 34 min, p baby hammocks, nor to older babies, particularly once the infant can roll. Given that it is not possible to predict when an infant will be able to roll, we strongly recommend that hammocks should not be used for unsupervised sleep. ©2014 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

High Flow Nasal Cannula Therapy for Improving Obstructive Sleep Apnea: A Case Report

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Se Joong Kim

2015-06-01

Full Text Available Although continuous positive airway pressure is the treatment of choice for obstructive sleep apnea, its compliance is low. Therefore, alternative therapeutic strategies are often required. High flow nasal cannula therapy uses an air compressor to deliver a constant flow of oxygen via the nasal cannula at a maximum of 60 L/m. It can produce positive end expiratory pressure and increase end expiratory pharyngeal pressure, which can help to alleviate upper airway obstruction. This is a case report of high flow nasal cannula therapy for a 71 year-old man. He had an obstructive sleep apnea and severe desaturation but failed to use continuous positive airway pressure. He underwent titration with high flow nasal cannula under polysomnography. Using high flow nasal cannula at an airflow of 45 L/m, his apnea-hypopnea, respiratory arousal and oxygen desaturation were improved. Importantly, he is very compliant with high flow nasal cannula therapy.

Double trouble: prolapsing epiglottis and unexpected dual pathology in an infant.

Science.gov (United States)

De Beer, David; Chambers, Neil

2003-06-01

A 3-week-old full-term female neonate was admitted with a 4-day history of episodic stridor, desaturations and difficult feeding. Initial assessment using fluoroscopy suggested distal tracheomalacia. Inhalational induction for examination under anaesthesia of the upper airway at 4 weeks of age caused almost complete airway obstruction due to severe anterior, or epiglottic, laryngomalacia. This airway obstruction was unresponsive to continuous positive airway pressure, the use of an oropharyngeal airway and hand ventilation and required urgent tracheal intubation using suxamethonium. Epiglottopexy, a relatively unknown procedure, was performed uneventfully 2 days later, with complete relief of the respiratory compromise. However, the infant remained desaturated postoperatively. A ventilation perfusion scan subsequently revealed multiple pulmonary arteriovenous malformations, unsuitable for embolization and requiring nocturnal home oxygen therapy. Review at 3 months of age found a thriving infant with no airway obstruction and good epiglottic positioning on examination under anaesthesia. Although the patient's oxygen requirements had diminished, the long-term outcome remains uncertain.

Acute medical complications in patients admitted to a stroke unit and safe transfer to rehabilitation.

Science.gov (United States)

Bonaiuti, Donatella; Sioli, Paolo; Fumagalli, Lorenzo; Beghi, Ettore; Agostoni, Elio

2011-08-01

Acute medical complications often prevent patients with stroke from being transferred from stroke units to rehabilitation units, prolonging the occupation of hospital beds and delaying the start of intensive rehabilitation. This study defined incidence, timing, duration and risk factors of these complications during the acute phase of stroke. A retrospective case note review was made of hospital admissions of patients with stroke not associated with other disabling conditions, admitted to a stroke unit over 12 months and requiring rehabilitation for gait impairment. In this cohort, a search was made of hypertension, oxygen de-saturation, fever, and cardiac and pulmonary symptoms requiring medical intervention. Included were 135 patients. Hypertension was the most common complication (16.3%), followed by heart disease (14.8%), oxygen de-saturation (7.4%), fever (6.7%) and pulmonary disease (5.2%). Heart disease was the earliest and shortest complication. Most complications occurred during the first week. Except for hypertension, all complications resolved within 2 weeks.

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.

Complex Evaluation Oxygen Status and Lipid Metabolism Indexes in Newborns with Perinatal Hypoxia and Hypovolemic Shock

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Svetlana A. Perepelitsa

2017-01-01

Full Text Available Aim. To asses of metabolism, lipid metabolism and oxygen status parameters in newborns with perinatal hypoxia.Materials and Methods. 53 newborn babies born with signs of severe hypoxia and low Apgar scoring equal to 2 at the 1st minute of life were enrolled in the study. Newborns were divided into 2 groups depending on the presence of the clinical presentation of shock: Group 1 «Shock» and Group 2 «Acute intranatal hypoxia» (AIH. All newborns underwent testing for blood gas and acid-base balance, lactate level. Cholesterol and triglyceride levels in the central venous blood were also tested immediately after the birth and on the 5th day of life. Mechanical ventilation mode and parameters were registered. The mean airway pressure (MAP and the oxygen saturation index (OSI were calculated.Results. Severe decompensated metabolic lactic acidosis was diagnosed in a «Shock» group newborns at birth, thus indicating severe perinatal hypoxia which had triggered the development of shock. As for the «AIH» group newborns, they had hyperlactatemia alone. The most severe hypoxemia at birth was diagnosed in newborns of the «Shock» group; the OSI value in these infants was significantly higher than that in «AIH» infants (P<0.01. Despite the treatment and mechanical ventilation, during the posthypoxic period, newborns from the «Shock» group were characterized by increased OSI values over 12 hours after birth. Significantly high levels of OSI persisted for 48 hours after the delivery. Severe hypotriglyceridemia and hypocholesterolemia were found in both group newborns.Conclusion. The study demonstrated that there was intranatal complex metabolism impairment in the case of perinatal hypoxia; at birth, it manifested by metabolic acidosis of various degrees of severity and imbalance of triglycerides and cholesterol levels. The longer and more severe hypoxia is, the more severe acid-base balance and blood lactate level impairment at birth become

Reduced cerebral oxygen–carbohydrate index during endotracheal intubation in vascular surgical patients

DEFF Research Database (Denmark)

Fabricius-Bjerre, Andreas; Overgaard, Anders; Winther-Olesen, Marie

2015-01-01

Brain activation reduces balance between cerebral consumption of oxygen versus carbohydrate as expressed by the so-called cerebral oxygen-carbohydrate-index (OCI). We evaluated whether preparation for surgery, anaesthesia including tracheal intubation and surgery affect OCI. In patients undergoing...... aortic surgery, arterial to internal jugular venous (a-v) concentration differences for oxygen versus lactate and glucose were determined from before anaesthesia to when the patient left the recovery room. Intravenous anaesthesia was supplemented with thoracic epidural anaesthesia for open aortic surgery...

Oxygenation impairment after total arch replacement with a stented elephant trunk for type-A dissection.

Science.gov (United States)

Shen, Yuwen; Liu, Chuanzhen; Fang, Changcun; Xi, Jie; Wu, Shuming; Pang, Xinyan; Song, Guangmin

2018-06-01

To study the risk factors of oxygenation impairment in patients with type-A acute aortic dissection who underwent total arch replacement with a stented elephant trunk. In this study, 169 consecutive patients were enrolled who were diagnosed with type-A acute aortic dissection and underwent a total arch replacement procedure at the Qilu Hospital of Shandong University between January 2015 and February 2017. Postoperative oxygenation impairment was defined as arterial oxygen partial pressure/inspired oxygen fraction ≤ 200 with positive end expiratory pressure ≥ 5 cm H 2 O that occurred within 72 hours of surgery. Perioperative clinical characteristics of all patients were collected and univariable analyses were performed. Risk factors associated with oxygenation impairment identified by univariable analyses were included in the multivariable regression analysis. The incidence of postoperative oxygenation impairment was 48.5%. Postoperative oxygenation impairment was associated with prolonged mechanical ventilation time, intensive care unit stay, and hospital stay. Multivariable regression analysis demonstrated that body mass index (odds ratio [OR], 1.204; 95% confidence interval [CI], 1.065-1.361; P = .003), preoperative oxygenation impairment (OR, 9.768; 95% CI, 4.159-22.941; P impairment. Postoperative oxygenation impairment is a common complication of surgery for type-A acute aortic dissection. Body mass index, preoperative oxygenation impairment, preoperative homocysteine, circulatory arrest time, and plasma transfusion were independent risk factors for oxygenation impairment after a total arch replacement procedure. Copyright © 2018 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Dissolved oxygen content as an index of water quality in San Vicente Bay, Chile (36 degrees 45'S).

Science.gov (United States)

Rudolph, Anny; Ahumada, Ramón; Pérez, Claudio

2002-08-01

The present report describes some effects of industrial and municipal effluents on the waters of San Vicente Bay. Analyses of the main substances contained in the fishing industry effluent suggest rating criteria based on the oxygen saturation of the water as an assessment of organic pollution. Six cruises were carried out throughout the Bay, from June to December 1996. Water samples were analyzed for dissolved oxygen, oil and grease content, and sediment samples for organic matter content. Water parameters (salinity, temperature) were used to characterize the Bay's hydrography, and to calculate values for oxygen saturation. The measurements demonstrated a local broad range of oxygen deficit, with a maximum of 45% in the winter to 95% in the spring. In November more than 65% of the Bay's area showed oxygen deficits greater than 40%. Organic matter was unusually high in sediments along the northern sector of the Bay. The results suggest that the oxygen depletion was a representative parameter for establishing a relative scale of water quality in this Bay.

Transcranial Doppler ultrasonography in children with sickle cell anemia: Clinical and laboratory correlates for elevated blood flow velocities.

Science.gov (United States)

Lagunju, IkeOluwa; Sodeinde, Olugbemiro; Brown, Biobele; Akinbami, Felix; Adedokun, Babatunde

2014-02-01

Transcranial Doppler (TCD) sonography of major cerebral arteries is now recommended for routine screening for stroke risk in children with sickle cell disease (SCD). We performed TCD studies on children with sickle cell anemia (SCA) seen at the pediatric hematology clinic over a period of 2 years. TCD scans were repeated yearly in children with normal flow velocities and every 3 months in children with elevated velocities. Findings were correlated with clinical variables, hematologic indices, and arterial oxygen saturation. Predictors of elevated velocities were identified by multiple linear regressions. We enrolled 237 children and performed a total of 526 TCD examinations. Highest time-averaged maximum flow velocities were ≥170 cm/s in 72 (30.3%) cases and ≥200 cm/s in 20 (8.4%). Young age, low hematocrit, low hemoglobin, and arterial oxygen desaturation <95% showed significant correlations with presence of increased cerebral flow velocities. Low hematocrit, low hemoglobin concentration, young age, and low arterial oxygen desaturation predicted elevated cerebral blood flow velocities and, invariably, increased stroke risk, in children with SCA. Children who exhibit these features should be given high priority for TCD examination in the setting of limited resources. Copyright © 2013 Wiley Periodicals, Inc.

Effect of strain rate on sooting limits in counterflow diffusion flames of gaseous hydrocarbon fuels: Sooting temperature index and sooting sensitivity index

KAUST Repository

Wang, Yu

2014-05-01

The effect of the strain rate on the sooting limits in counterflow diffusion flames was investigated in various gaseous hydrocarbon fuels by varying the nitrogen dilution in the fuel and oxidizer streams. The sooting limit was defined as the critical fuel and oxygen mole fraction at which soot started to appear in the elastic light scattering signal. The sooting region for normal alkane fuels at a specified strain rate, in terms of the fuel and oxygen mole fraction, expanded as the number of carbon atoms increased. The alkene fuels (ethylene, propene) tested had a higher propensity for sooting as compared with alkane fuels with the same carbon numbers (ethane, propane). Branched iso-butane had a higher propensity for sooting than did n-butane. An increase in the strain rate reduced the tendency for sooting in all the fuels tested. The sensitivity of the sooting limit to the strain rate was more pronounced for less sooting fuels. When plotted in terms of calculated flame temperature, the critical oxygen mole fraction exhibited an Arrhenius form under sooting limit conditions, which can be utilized to significantly reduce the effort required to determine sooting limits at different strain rates. We found that the limiting temperatures of soot formation flames are viable sooting metrics for quantitatively rating the sooting tendency of various fuels, based on comparisons with threshold soot index and normalized smoke point data. We also introduce a sooting temperature index and a sooting sensitivity index, two quantitative measures to describe sooting propensity and its dependence on strain rate. © 2013 The Combustion Institute.

The effect of the severity of obstructive sleep apnea syndrome on telomere length.

Science.gov (United States)

Tempaku, Priscila Farias; Mazzotti, Diego Robles; Hirotsu, Camila; Andersen, Monica Levy; Xavier, Gabriela; Maurya, Pawan Kumar; Rizzo, Lucas Bortolotto; Brietzke, Elisa; Belangero, Sintia Iole; Bittencourt, Lia; Tufik, Sergio

2016-10-25

Aging is associated with an increase in the prevalence of obstructive sleep apnea syndrome (OSAS) as well as the shortening of telomeres. It is known that OSAS-related factors are stimuli that can contribute to the acceleration of cellular senescence. Thus, the present study aimed to compare the leukocyte telomere length (LTL) between OSAS patients and controls, as well as to verify the correlation between LTL and sleep parameters. We used DNA extracted of 928 individuals from EPISONO to measure the LTL by the quantitative real-time polymerase chain reaction. All individuals were subjected to one full-night polysomnography. LTL was significantly shorter in OSAS patients compared to controls. The results showed negative correlations between LTL and the following variables: apnea-hypopnea index, respiratory disturbance index, desaturation index and wake after sleep onset. LTL was positively correlated with sleep efficiency, total sleep time, basal, minimum and maximum oxygen saturation. Lastly, it was observed that OSAS severity was associated with shorter LTL even after adjusting for sex, age, years of schooling, body mass index, diabetes, stroke and heart attack. In conclusion, our study indicates the presence of an association between LTL and OSAS and a significant impact of severity of OSAS in telomeres shortening.

Water Quality Index in the Vicinity of Pelepah Kanan Mine, Kota Tinggi, Johor

International Nuclear Information System (INIS)

Wan Mohd Razi Idris; Sahibin Abdul Rahim; Mohd Talib Latif; Zulfahmi Ali Rahman; Tukimat Lihan; Chong, L.Y.; Azman Hashim; Shahrinizam Mohd Yusuf

2009-01-01

This study was carried out to determine the water quality index at the Pelepah Kanan River, Kota Tinggi, Johor. Six stations were chosen from different part of the river from upstream to downstream to represent the water quality index along this river. Three replicates of samples were taken from each station. Samples were collected in two different seasons namely dry season (July) and rainy season (December) 2007. In-situ physico-chemical measurements included temperature, ph, dissolved oxygen and conductivity. Physico-chemical parameters determined in the laboratory were turbidity, total suspended solid (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and ammonia nitrogen (NH3-N). According to the Interim National Water Quality Standards (INWQS), results showed that all sampling stations along the Pelepah Kanan River in July fall in Class I-II for physical and chemical parameters except for dissolved oxygen and pH which was in Class I-II. The results obtained in December also showed that all sampling stations fall in Class I for physical and chemical parameters except for pH which was in Class III. Correlation test showed that some physico- chemical parameters have significant correlation with each other. Water Quality Index (WQI) analysis showed that the mean WQI value for the month of July is 96.88 (Class I) while for December, the WQI value deteriorated to 84.03 (Class II). According to the calculated values of WQI and comparison with INWQS, the index of water quality in Pelepah Kanan River is in the clean category and is not affected by pollution neither anthropogenic activities nor natural pollution. (author)

Severe cerebral desaturation during shoulder arthroscopy in the beach-chair position

DEFF Research Database (Denmark)

Dippmann, Christian; Winge, Søren; Nielsen, Henning Bay

2010-01-01

During shoulder arthroscopy in the beach-chair position, cerebral ischemia may be a serious complication because prolonged hypotension may affect regional cerebral oxygen supply. We present the cases of 2 patients in whom a reduction in mean arterial pressure after anesthesia provoked a decrease...

[Intermittent hypoxia due to sleep apnea syndrome in patients with type 2 diabetes mellitus].

Science.gov (United States)

Burchakov, D I; Mayorov, A Yu

To evaluate the possible association between intermittent hypoxia (IH) and HbA1c in patients with insufficient control type of 2 diabetes mellitus (T2DM). In this cross-sectional study 183 patients with HbAc1≥7% underwent three-channel overnight monitoring (ApneaLink) and completed Berlin Questionnaire, Epworth Sleepiness Scale and Pittsburgh Sleep Quality Index. Patients were divided in two groups, based on the cut-off value of oxygen desaturation index≥15. There were 79 (43%) patients with intermittent hypoxia, which was associated with poorer glycaemic control, defined as HbA1c>8.7% (sample median) in the univariate analysis and after adjustment for body mass index OR 2,40 (CI 1.21-4.95, p=0.021). Neither of three questionnaires yielded satisfactory results as a screening method in patients with T2DM. There is a need to implement instrumental screening of sleep-disordered breathing in this population and to study the effects of CPAP-therapy on glycaemic control and carbohydrate metabolism.

The predictive value of drug-induced sleep endoscopy for CPAP titration in OSA patients.

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Lan, Ming-Chin; Hsu, Yen-Bin; Lan, Ming-Ying; Huang, Yun-Chen; Kao, Ming-Chang; Huang, Tung-Tsun; Chiu, Tsan-Jen; Yang, Mei-Chen

2017-12-15

The aim of this study was to identify possible upper airway obstructions causing a higher continuous positive airway pressure (CPAP) titration level, utilizing drug-induced sleep endoscopy (DISE). A total of 76 patients with obstructive sleep apnea (OSA) underwent CPAP titration and DISE. DISE findings were recorded using the VOTE classification system. Polysomnographic (PSG) data, anthropometric variables, and patterns of airway collapse during DISE were analyzed with CPAP titration levels. A significant association was found between the CPAP titration level and BMI, oxygen desaturation index (ODI), apnea-hypopnea index (AHI), and neck circumference (NC) (P CPAP titration level (P CPAP titration level and any other collapse at the tongue base or epiglottis. By analyzing PSG data, anthropometric variables, and DISE results with CPAP titration levels, we can better understand possible mechanisms resulting in a higher CPAP titration level. We believe that the role of DISE can be expanded as a tool to identify the possible anatomical structures that may be corrected by oral appliance therapy or surgical intervention to improve CPAP compliance.

A randomized cross over study comparing the efficacy of two mandibular advancement appliances in the treatment of mild-moderate obstructive sleep apnea.

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Al-Dharrab, Ayman

2017-11-01

To compare efficacy, side effects, patient compliance, and preference between two types of custom-made mandibular advancement appliances (MAAs) in the treatment of patients with mild to moderate obstructive sleep apnea (OSA). This prospective, randomized, crossover study of 12 patients with mild to moderate OSA compared a titratable and a non-titratable MAA. Each patient was fitted with both appliances in a random order with a washout period of two weeks. Efficacy, side effects, compliance, and preference were evaluated by a questionnaire. All patients underwent overnight home sleep recordings prior to and after the use of each appliance in order to objectively assess sleep quality in terms of the apnea and hypopnea index (AHI), snoring frequency and oxygen desaturation index. Treatment successes (relief of symptoms and/or reduction of AHI to appliances. No compliance failure was reported, and in most patients, the side effects were mild, and improved with time. Both types of oral appliances were effective treatments for patients with mild to moderate OSA, with fewer side effects and higher patient satisfaction.

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

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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.

Body position and late postoperative nocturnal hypoxaemia

DEFF Research Database (Denmark)

Rosenberg-Adamsen, S; Stausholm, K; Edvardsen, L

1997-01-01

Thirteen patients were monitored for nocturnal body position (supine vs. side) and arterial oxygen saturation pre-operatively and on the second postoperative night after major abdominal surgery. The number of positional changes were significantly decreased after operation (p ... position than on the side (p movements....... towards more time spent in the supine position (p = 0.1). Individual mean arterial oxygen saturation decreased postoperatively (p positions (p = 0.9). Pre-operatively, episodic desaturations were significantly more frequent in the supine...

[Daytime tiredness correlated with nocturnal respiratory and arousal variables in patients with sleep apnea: polysomnographic and EEG mapping studies].

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Saletu, M; Hauer, C; Anderer, P; Saletu-Zyhlarz, G; Gruber, G; Oberndorfer, S; Mandl, M; Popovic, R; Saletu, B

2000-03-24

There is evidence that daytime tiredness is caused by apnea/hypopnea with oxygen desaturation and/or by sleep fragmentation due to arousals. The aim of this study was to investigate objective and subjective sleep and awakening quality and daytime vigilance--objectified by midmorning mapping of vigilance-controlled EEG (V-EEG)--in sleep apnea patients (N: 18), as compared with age- and sex-matched normal controls (N: 18) as well as to correlate nocturnal respiratory distress and arousals to daytime brain function. Statistical analyses demonstrated a deterioration in subjective and objective sleep and awakening quality in apnea patients. Midmorning V-EEG mapping in apnea patients exhibited less total power, more delta and theta, less alpha and beta activity, as well as a slower dominant frequency and centroid of the total activity compared to controls, which suggests a vigilance decrement. The Spearman rank correlation between 6 polysomnographically registered respiratory variables and 36 diurnal quantitative EEG measures demonstrated the following: the higher the apnea, apnea-hypopnea, snoring and desaturation indices and the lower the minimum and average low oxygen saturation, the more pronounced was diurnal tiredness. Eleven arousal measures based on ASDA criteria showed the following significant correlations: the higher the nocturnal arousal index and the more arousals due to hypopneas, the greater was daytime tiredness. On the other hand, the greater the average frequency change during arousals and the more spontaneous arousals, the better was daytime vigilance. Our findings show that, in contrast to the lengthy Multiple Sleep Latency (MSLT) and Maintenance of Wakefulness (MWT) tests which evaluate sleep pressure under resting conditions conducive to sleep, V-EEG mapping provides a brief objective measure of a sleep apnea patient's daytime tiredness under conditions of wakefulness more appropriate to reflect the patient's everyday life.

Markers of Myocardial Ischemia in Patients with Obstructive Sleep Apnea and Coronary Artery Disease

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Misa Valo

2015-01-01

Full Text Available Obstructive sleep apnea (OSA is characterized by intermittent hypoxia during sleep. We tested the hypothesis that nocturnal myocardial ischemia is detectable by ST segment depression and elevation of high sensitive troponin T (hsTrop T and B-type natriuretic peptide (NT-proBNP in patients with OSA and coexisting coronary artery disease (CAD. Twenty-one patients with OSA and CAD and 20 patients with OSA alone underwent in-hospital polysomnography. Blood samples for hsTrop T and NT-proBNP measurements were drawn before and after sleep. ST segment depression was measured at the time of maximum oxygen desaturation during sleep. The apnea-hypopnea-index (AHI, oxygen saturation nadir, and time in bed with oxygen saturation of ≤80% were similar in both groups. Levels of hsTrop T and NT-proBNP did not differ significantly before and after sleep but NT-proBNP levels were significantly higher in patients suffering from OSA and CAD compared to patients with OSA alone. No significant ST depression was found at the time of oxygen saturation nadir in either group. Despite the fact that patients with untreated OSA and coexisting CAD experienced severe nocturnal hypoxemia, we were unable to detect myocardial ischemia or myocyte necrosis based on significant ST segment depression or elevation of hsTrop T and NT-proBNP, respectively.

MAPA em portadores de DPOC com dessaturação no sono MAPA en portadores de EPOC con desaturación durante el sueño ABPM in COPD patients with sleep desaturation

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Neila Anders Aidar

2009-09-01

COPD patients who do not present sleep apnea, but do present sleep desaturation. OBJECTIVES: To analyze blood pressure parameters in COPD patients with sleep desaturation not caused by apnea. METHODS: Thirteen patients with COPD underwent spirometry, blood gas, polysomnography and ABPM for blood pressure evaluation. Fourteen patients without COPD underwent spirometry, oximetry and ABPM. Blood pressure analyses were carried out both during wakefulness and sleep. Both groups were comprised of patients with no history of hypertension. RESULTS: The two groups were similar as regards age, height, weight, and body mass index. A significant difference (p<0.05 was found between blood pressure levels during the wakefulness, sleep, 24-hour and sleep dip periods. Higher blood pressure levels were observed in patients with COPD, except for diastolic levels during wakefulness and maximum values during sleep and in the 24 hours. Sleep dip in the COPD group was attenuated, whereas physiological dip was observed in the control group, with lower blood pressure levels. CONCLUSIONS: Systolic and diastolic blood pressure levels in the COPD group were higher than those of the control group, with a significant difference found for all periods studied, except for diastolic levels during wakefulness and in the 24 hours. We can conclude that the group of COPD patients with sleep desaturation has significantly higher blood pressure levels than the control group.

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

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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.

Estimation of Physiological Cost Index as an Energy Expenditure Index using MacGregor’s Equation

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Binaya SJB Rana

2015-09-01

Full Text Available Introduction: Physical activity and energy expenditure can be quantified by measuring heart rate, oxygen uptake and respiratory quotient. The Physiological Cost Index (PCI proposed by MacGregor is a simple and straightforward method to estimate the energy expenditure index. Here, we aim to estimate the energy expenditure among young Asian population using MacGregor’s equation. Methods: A total of 50 young randomly selected healthy females performed 50m, 100m and 150m walking test at their self-selected preferred speed. The physiological cost index values for 100 m walk at speeds slower and faster than the preferred speed were also obtained. The physiological cost index during exercise was calculated using MacGregor’s equation considering heart rate and speed of walking over the varying distances. Results: The PCI values on three different distances are consistent during self selected preferred speed. The PCI estimation on second and third tests for all three distances walked consistently reproducible. However for each distance walked, the first test the PCI was significantly higher than the second and third test values. The PCI values increased significantly when subjects walked either slower (p = 0.02 or faster (p = 0.001 than their normal preferred speed. Conclusion: The physiological cost index values were similar for varying distances walks. The PCI was the least at the preferred speed of walking and increased when the subjects either walked slower or faster than the preferred speed. The first estimation was higher than subsequent estimations. Keywords: energy expenditure index; exercise; physiological cost index. | PubMed

Haemodynamics and oxygenation improvement induced by high frequency percussive ventilation in a patient with hypoxia following cardiac surgery: a case report

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Persi Bruno

2010-10-01

Full Text Available Abstract Introduction High frequency percussive ventilation is a ventilatory technique that delivers small bursts of high flow respiratory gas into the lungs at high rates. It is classified as a pneumatically powered, pressure-regulated, time-cycled, high-frequency flow interrupter modality of ventilation. High frequency percussive ventilation improves the arterial partial pressure of oxygen with the same positive end expiratory pressure and fractional inspiratory oxygen level as conventional ventilation using a minor mean airway pressure in an open circuit. It reduces the barotraumatic events in a hypoxic patient who has low lung-compliance. To the best of our knowledge, there have been no papers published about this ventilation modality in patients with severe hypoxaemia after cardiac surgery. Case presentation A 75-year-old Caucasian man with an ejection fraction of 27 percent, developed a lung infection with severe hypoxaemia [partial pressure of oxygen/fractional inspiratory oxygen of 90] ten days after cardiac surgery. Conventional ventilation did not improve the gas exchange. He was treated with high frequency percussive ventilation for 12 hours with a low conventional respiratory rate (five per minute. His cardiac output and systemic and pulmonary pressures were monitored. Compared to conventional ventilation, high frequency percussive ventilation gives an improvement of the partial pressure of oxygen from 90 to 190 mmHg with the same fractional inspiratory oxygen and positive end expiratory pressure level. His right ventricular stroke work index was lowered from 19 to seven g-m/m2/beat; his pulmonary vascular resistance index from 267 to 190 dynes•seconds/cm5/m2; left ventricular stroke work index from 28 to 16 gm-m/m2/beat; and his pulmonary arterial wedge pressure was lowered from 32 to 24 mmHg with a lower mean airway pressure compared to conventional ventilation. His cardiac index (2.7 L/min/m2 and ejection fraction (27 percent

The impact of a standardised intramuscular sedation protocol for acute behavioural disturbance in the emergency department

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Downes Michael A

2010-06-01

Full Text Available Abstract Background Acute behavioural disturbance (ABD is an increasing problem in emergency departments. This study aimed to determine the impact of a structured intramuscular (IM sedation protocol on the duration of ABD in the emergency department. Methods A historical control study was undertaken comparing 58 patients who required physical restraint and parenteral sedation with the structured IM sedation protocol, to 73 historical controls treated predominantly by intravenous sedation, according to individual clinician preference. The primary outcome was the duration of the ABD defined as the time security staff were required. Secondary outcomes were the requirement for additional sedation, drug related-adverse effects and patient and staff injuries. Results The median duration of the ABD in patients with the new sedation protocol was 21 minutes (IQR: 15 to 35 minutes; Range: 5 to 78 minutes compared to a median duration of 30 minutes (IQR: 15 to 50 minutes; Range: 5 to 135 minutes in the historical controls which was significantly different (p = 0.03. With IM sedation only 27 of 58 patients (47%; 95% CI: 34% to 60% required further sedation compared to 64 of 73 historical controls (88%; 95%CI: 77% to 94%. There were six (10% drug-related adverse events with the new IM protocol [oxygen desaturation (5, oxygen desaturation/airway obstruction (1] compared to 10 (14% in the historical controls [oxygen desaturation (5, hypoventilation (4 and aspiration (1]. Injuries to staff occurred with three patients using the new sedation protocol and in seven of the historical controls. Two patients were injured during the new protocol and two of the historical controls. Conclusion The use of a standardised IM sedation protocol was simple, more effective and as safe for management of ABD compared to predominantly intravenous sedation.

Author Details - African Journals Online

African Journals Online (AJOL)

Parrinello, G. Vol 8, No 1 (2013) - Articles Letter to Editor: Hiatal herniation of the stomach and pancreas in a patient with oxygen desaturations. Abstract PDF. ISSN: 1819-6357. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners ...

Low bone mineral density in COPD patients with osteoporosis is related to low daily physical activity and high COPD assessment test scores

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Liu WT

2015-09-01

Full Text Available Wen-Te Liu,1,2,* Han-Pin Kuo,3,* Tien-Hua Liao,4 Ling-Ling Chiang,1 Li-Fei Chen,3 Min-Fang Hsu,5 Hsiao-Chi Chuang,1 Kang-Yun Lee,2,6 Chien-Da Huang,3 Shu-Chuan Ho11School of Respiratory Therapy, College of Medicine, Taipei Medical University, 2Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, 3Department of Thoracic Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 4Department of Respiratory Therapy, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taipei, 5Department of Healthcare Administration, Asia University, Wufeng, Taichung, 6Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan*These authors contributed equally to this workAbstract: COPD patients have an increased prevalence of osteoporosis (OP compared with healthy people. Physical inactivity in COPD patients is a crucial risk factor for OP; the COPD assessment test (CAT is the newest assessment tool for the health status and daily activities of COPD patients. This study investigated the relationship among daily physical activity (DPA, CAT scores, and bone mineral density (BMD in COPD patients with or without OP. This study included 30 participants. Ambulatory DPA was measured using actigraphy and oxygen saturation by using a pulse oximeter. BMD was measured using dual-energy X-ray absorptiometry. OP was defined as a T-score (standard deviations from a young, sex-specific reference mean BMD less than or equal to -2.5 SD for the lumbar spine, total hip, and femoral neck. We quantified oxygen desaturation during DPA by using a desaturation index and recorded all DPA, except during sleep. COPD patients with OP had lower DPA and higher CAT scores than those of patients without OP. DPA was significantly positively correlated with (lumbar spine, total hip, and femoral neck BMD (r=0.399, 0.602, 0.438, respectively

The relationship between tumor oxygenation and cell proliferation in human soft tissue sarcomas

International Nuclear Information System (INIS)

Nordsmark, Marianne; Hoeyer, Morten; Keller, Johnny; Nielsen, Ole Steen; Jensen, Oluf Myhre; Overgaard, Jens

1996-01-01

Purpose: In malignant tumors the oxygenation status and tumor cell proliferation are known to influence local tumor control after radiotherapy. However, the relationship between oxygenation status and tumor cell kinetics in human tumors has not yet been described. Newly developed clinically applicable techniques such as oxygen electrode measurements and assessment of tumor cell proliferation rates have been suggested as promising predictive assays. The purpose of the present study was to characterize tumor oxygenation status in soft tissue sarcomas and to compare this with tumor cell kinetics and clinical parameters. Methods and Materials: Pretreatment tumor oxygenation status was measured by polarographic oxygen needle electrodes and evaluated as the median pO 2 and the percentage of pO 2 values ≤ 5 mmHg and ≤ 2.5 mmHg in 22 patients with primary soft tissue sarcomas. All tumors were characterized by histology, grade of malignancy, the level of microscopic necrosis, the level of effective hemoglobin, and magnetic resonance imaging estimation of tumor volume. The tumor cell potential doubling time and labeling index were measured by flow cytometric and immunohistochemical analysis of tumor biopsy specimens after in vivo incorporation of iododeoxyuridine. Results: There was a significant correlation between the median pO 2 and the tumor cell potential doubling time (p = 0.041), whereas no correlation was found between the level of hypoxia expressed by the percentage of pO 2 values ≤ 2.5 and ≤ 5 mmHg, respectively, and tumor cell potential doubling time. Furthermore, no correlation was found between either of the three tumor oxygenation parameters and labeling index. The material represented large intertumor heterogeneity in oxygenation status, cell kinetics, and tumor volume, and no correlation was found between oxygenation status and either volume, histopathology, grade of malignancy, or effective hemoglobin. Conclusion: This report is the first to suggest

The oxygen reactivity index and its relation to sensor technology in patients with severe brain lesions.

Science.gov (United States)

Dengler, Julius; Frenzel, Christin; Vajkoczy, Peter; Horn, Peter; Wolf, Stefan

2013-08-01

The oxygen reactivity index (ORx) has been introduced to assess the status of cerebral autoregulation after traumatic brain injury (TBI) or subarachnoid hemorrhage (SAH). Currently, there is some controversy about whether the ORx depends on the type of PbrO2-sensor technology used for its calculation. To examine if the probe technology does matter, we compared the ORx and the resulting optimal cerebral perfusion pressures (CPPopt) of simultaneously implanted Licox (CC1.SB, Integra Neuroscience, France) and Neurovent-PTO (Raumedic, Germany) probes in patients after aneurysmal SAH or severe TBI. Licox and Raumedic probes were implanted side by side in 11 patients after TBI or SAH. ORx and CPPopt were recorded continuously. The equivalence of both probes was examined using Bland-Altman analyses. The mean difference in ORx was 0.1, with Licox producing higher values. The limits of agreement regarding ORx ranged from -0.6 to +0.7. When both probes' ORx values were compared in each patient, no specific pattern in their relationship was seen. The mean difference in CPPopt was 0 mmHg with limits of agreement between -16.5 and +16.4 mmHg. Owing to the rather limited number of patients, we view the results of this study as preliminary. The main result is that Licox and Raumedic showed consistent differences in ORx and CPPopt. Therefore, ORx values of both probes cannot be interchanged and should not be viewed as equivalent. This should be taken into consideration when discussing ORx data generated by different PbrO2 probe types.

Videoradiography at submental electrical stimulation during apnea in obstructive sleep apnea syndrome

International Nuclear Information System (INIS)

Hillarp, B.; Rosen, I.; Wickstroem, O.; Malmoe Allmaenna Sjukhus

1991-01-01

Percutaneous submental electrical stimulation during sleep may be a new therapeutic method for patients with obstructive sleep apnea syndrome (OSAS). Electrical stimulation to the submental region during obstructive apnea is reported to break the apnea without arousal and to diminish apneic index, time spent in apnea, and oxygen desaturation. The mode of breaking the apnea by electrical stimulation has not yet been shown. However, genioglossus is supposed to be the muscle responsible for breaking the apnea by forward movement of the tongue. To visualize the effect of submental electrical stimulation, one patient with severe OSAS has been examined with videoradiography. Submental electrical stimulation evoked an immediate complex muscle activity in the tongue, palate, and hyoid bone. This was followed by a forward movement of the tongue which consistently broke obstructive apnea without apparent arousal. Time spent in apnea was diminished but intervals between apnea were not affected. (orig.)

Neonatal cerebral oxygenation is not linked to foetal vasculitis and predicts intraventricular haemorrhage in preterm infants

DEFF Research Database (Denmark)

Sorensen, Line C; Maroun, Lisa L; Borch, Klaus

2008-01-01

Aim: The aim of the study was to compare the cerebral tissue oxygenation index (c-TOI) measured by near infrared spectroscopy (NIRS) in infants with and without foetal vasculitis. Methods: Twenty-four infants with placental signs of a foetal inflammatory response (FIR), foetal vasculitis, were.......002). Conclusion: Cerebral oxygenation was not affected in the first day of life in preterm infants born with foetal vasculitis, while cerebral oxygenation in infants that later developed intraventricular haemorrhage was impaired....

Sleep-disordered breathing, behavior, and academic performance in Taiwan schoolchildren.

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Ting, Hua; Wong, Ruey-Hong; Yang, Hao-Jan; Lee, Shu-Ping; Lee, Shin-Da; Wang, Lee

2011-01-01

The behaviors of children may be affected by sleep-disordered breathing (SDB). This study adopts a cross-sectional approach to investigate the relationship between the sleep apneas-hypopneas index during sleep and the behavioral and academic performance of schoolchildren in Taiwan. A total of 138 children (85 boys and 53 girls), ages 6-11, were recruited from two elementary schools to participate in this study. Overnight polysomnographic examinations in hospital were performed to assess sleep quality, including total sleep time, arousal index, apneas-hypopneas index, desaturation index, and lowest oxygen saturation, as well as the percentage of total sleep time spent in rapid eye movement, stage 1, stage 2, stage 3, and stage 4. The children's parents and teachers were required to complete a Chinese version of the Child Behavior Checklist and Teacher's Report Form to assess child behavior and academic achievement. Compared with children without SDB (apneas-hypopneas index ≤1), those with severe SDB (apneas-hypopneas index >15) exhibited more irregular behavioral performance in somatic complaints (odds ratio (OR) = 9.43; 95% confidence interval (CI) = 1.04-85.71) and attention (OR = 9.95; 95% CI = 1.02-97.00). However, different severities of SDB groups did not show significant associations in academic performance. Our study suggests that children with severe SDB may predispose to somatic complaints and attention problems so that sleep examination or medical intervention might be provided at an early age in these children.

Electrical and optical properties of reactive DC magnetron sputtered silver oxide thin films: role of oxygen

Energy Technology Data Exchange (ETDEWEB)

Kumar Barik, Ullash; Srinivasan, S; Nagendra, C L; Subrahmanyam, A

2003-04-01

Silver oxide thin films have been prepared on soda lime glass substrates at room temperature (300 K) by reactive DC Magnetron sputtering technique using pure silver metal target; the oxygen flow rates have been varied in the range 0.00-2.01 sccm. The X-ray diffraction data on these films show a systematic change from metallic silver to silver (sub) oxides. The electrical resistivity increases with increasing oxygen flow. The films show a p-type behavior (by both Hall and Seebeck measurements) for the oxygen flow rates of 0.54, 1.09 and 1.43 sccm. The refractive index of the films (at 632.8 nm) decreases with increasing oxygen content and is in the range 1.167-1.145, whereas the p-type films show a higher refractive index (1.186-1.204). The work function of these silver oxide films has been measured by Kelvin Probe technique. The results, in specific, the p-type conductivity in the silver oxide films, have been explained on the basis of the theory of partial ionic charge proposed by Sanderson.

Electrical and optical properties of reactive DC magnetron sputtered silver oxide thin films: role of oxygen

International Nuclear Information System (INIS)

Kumar Barik, Ullash; Srinivasan, S.; Nagendra, C.L.; Subrahmanyam, A.

2003-01-01

Silver oxide thin films have been prepared on soda lime glass substrates at room temperature (300 K) by reactive DC Magnetron sputtering technique using pure silver metal target; the oxygen flow rates have been varied in the range 0.00-2.01 sccm. The X-ray diffraction data on these films show a systematic change from metallic silver to silver (sub) oxides. The electrical resistivity increases with increasing oxygen flow. The films show a p-type behavior (by both Hall and Seebeck measurements) for the oxygen flow rates of 0.54, 1.09 and 1.43 sccm. The refractive index of the films (at 632.8 nm) decreases with increasing oxygen content and is in the range 1.167-1.145, whereas the p-type films show a higher refractive index (1.186-1.204). The work function of these silver oxide films has been measured by Kelvin Probe technique. The results, in specific, the p-type conductivity in the silver oxide films, have been explained on the basis of the theory of partial ionic charge proposed by Sanderson

Bi-level CPAP does not improve gas exchange when compared with conventional CPAP for the treatment of neonates recovering from respiratory distress syndrome.

Science.gov (United States)

Lampland, Andrea L; Plumm, Brenda; Worwa, Cathy; Meyers, Patricia; Mammel, Mark C

2015-01-01

We hypothesised that short-term application of bi-level nasal continuous positive airway pressure CPAP (SiPAP) compared with conventional nasal CPAP (nCPAP) at the same mean airway pressure in infants with persistent oxygen need recovering from respiratory distress syndrome would improve CO2 removal with no change in oxygen requirement. Non-blinded, randomised, observational four-period crossover study. Level III NICU; low-birthweight infants requiring CPAP and oxygen while recovering from respiratory distress syndrome. Infants requiring nasal CPAP for >24 h prior to study enrolment, and fraction of inspired oxygen requirement (FiO2) of 0.25-0.5, were randomised to either nCPAP or SiPAP. A crossover design with four 1 h treatment periods was used such that each infant received both treatments twice. Oxygen saturations (SaO2), transcutaneous CO2 (tcCO2) and vital signs were monitored continuously. Polysomnographic recordings were analysed for apnoea, bradycardia and oxygen desaturation. Twenty low-birthweight infants receiving 0.3±0.04% supplemental oxygen on CPAP of 6 cm H2O were studied at an average of 33 days of age (±23 days, SD). There were no differences in tcCO2 or other physiological parameters except mean blood pressure, which was lower during nCPAP (52.3±8.3 vs 54.4±9.1 mm Hg; ±SD; p<0.01). No differences in short or prolonged apnoea, bradycardia or significant desaturation events were observed. At similar mean airway pressures, SiPAP does not improve CO2 removal, oxygenation or other studied physiological parameters with the exception of mean blood pressure, which was not clinically significant. NCT01053455. 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.

[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.

[Metabolic profile in obese patients with obstructive sleep apnea. A comparison between patients with insulin resistance and with insulin sensitivity].

Science.gov (United States)

Dumitrache-Rujinski, Stefan; Dinu, Ioana; Călcăianu, George; Erhan, Ionela; Cocieru, Alexandru; Zaharia, Dragoş; Toma, Claudia Lucia; Bogdan, Miron Alexandru

2014-01-01

Obstructive sleep apnea syndrome (OSAS) may induce metabolic abnormalities through intermittent hypoxemia and simpathetic activation. It is difficult to demonstrate an independent role of OSAS in the occurrence of metabolic abnormalities, as obesity represents an important risk factor for both OSAS and metabolic abnormalities. to assess the relations between insulin resistance (IR), insulin sensitivity (IS), OSAS severity and nocturnal oxyhaemoglobin levels in obese, nondiabetic patients with daytime sleepiness. We evaluated 99 consecutive, obese, nondiabetic patients (fasting glycemia 5/hour and daytime sleepiness) by an ambulatory six channel cardio-respiratory polygraphy. Hight, weight serum triglycerides (TG), high density lipoprotein-cholesterol (HDL-C) levels were evaluated. Correlations between Apneea Hypopnea Index (AHI), Oxygen Desaturation Index (ODI), average and lowest oxyhaemoglobin saturation (SaO), body mass index (BMI) and insulin resistance or sensitivity were assesed. IR was defined as a TG/ HDL-Cratio > 3, and insulin sensitivity (IS) as a TG/HDL-C ratio obese nondiabetic patients. Preserving insulin sensitivity is more likely when oxyhaemoglobin levels are higher and ODI is lower. Mean lowest nocturnal SaO2 levels seems to be independently involved in the development of insulin resistance as no statistically significant differences were found for BMI between the two groups.

Detection of myoglobin desaturation in Mirounga angustirostris during apnea.

Science.gov (United States)

Ponganis, Paul J; Kreutzer, Ulrike; Sailasuta, Napapon; Knower, Torre; Hurd, Ralph; Jue, Thomas

2002-01-01

1H NMR solution-state study of elephant seal (Mirounga angustirostris) myoglobin (Mb) and hemoglobin (Hb) establishes the temperature-dependent chemical shifts of the proximal histidyl N(delta)H signal, which reflects the respective intracellular and vascular PO2 in vivo. Both proteins exist predominantly in one major isoform and do not exhibit any conformational heterogeneity. The Mb and Hb signals are detectable in M. angustirostris tissue in vivo. During eupnea M. angustirostris muscle maintains a well-saturated MbO2. However, during apnea, the deoxymyoglobin proximal histidyl N(delta)H signal becomes visible, reflecting a declining tissue PO2. The study establishes a firm methodological basis for using NMR to investigate the metabolic responses during sleep apnea of the elephant seal and to secure insights into oxygen regulation in diving mammals.

Neonatal cerebral oxygenation is not linked to foetal vasculitis and predicts intraventricular haemorrhage in preterm infants

DEFF Research Database (Denmark)

Sørensen, Line Carøe; Maroun, Lisa Leth; Borch, K.

2008-01-01

AIM: The aim of the study was to compare the cerebral tissue oxygenation index (c-TOI) measured by near infrared spectroscopy (NIRS) in infants with and without foetal vasculitis. METHODS: Twenty-four infants with placental signs of a foetal inflammatory response (FIR), foetal vasculitis, were.......002). CONCLUSION: Cerebral oxygenation was not affected in the first day of life in preterm infants born with foetal vasculitis, while cerebral oxygenation in infants that later developed intraventricular haemorrhage was impaired Udgivelsesdato: 2008/11...

Theoretical analysis and experimental study of oxygen transfer under regular and non-breaking waves

Institute of Scientific and Technical Information of China (English)

尹则高; 梁丙臣; 王乐

2013-01-01

The dissolved oxygen concentration is an important index of water quality, and the atmosphere is one of the important sources of the dissolved oxygen. In this paper, the mass conservation law and the dimensional analysis method are employed to study the oxygen transfer under regular and non-breaking waves, and a unified oxygen transfer coefficient equation is obtained with consi-deration of the effect of kinetic energy and wave period. An oxygen transfer experiment for the intermediate depth water wave is per-formed to measure the wave parameters and the dissolved oxygen concentration. The experimental data and the least squares method are used to determine the constant in the oxygen transfer coefficient equation. The experimental data and the previous reported data are also used to further validate the oxygen transfer coefficient, and the agreement is satisfactory. The unified equation shows that the oxygen transfer coefficient increases with the increase of a parameter coupled with the wave height and the wave length, but it de-creases with the increase of the wave period, which has a much greater influence on the oxygen transfer coefficient than the coupled parameter.

Evaluation of Oxygen Deficit Stress on Germination Indicators and Seedling

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F Hoseini

2012-06-01

Full Text Available To investigate the relationship oxygen deficit stress on germination indicators and seedling growth of five wheat cultivars in laboratory condition, an experiment with Randomized Complete Block design in factorial arrangement with three replications was conducted in 2008. The treatments consisted of five wheat cultivars (Chamran, Flat, Roshan, Stare and Shole as A factor, and two oxygen level (normal seed and seed under oxygen deficit stress conditions as B factor in each of these figures was done. Results showed that oxygen deficit stress caused to decrease for various cultivars germination percentage, germination rate, allometric coefficient, seed vigor index and other germination indicators. Therefore, this test as a suitable method for determining the quality of various seed lot can be used in the water logging condition. In addition, among different cultivars characterized that Roshan cultivar was more resistant to oxygen deficit stress than Chamran, Flat and Star cultivars. Although Chamran cultivar is common cultivar in Khouzestan, but of look most germination indicators arranged as weak seed class. The highest correlation coefficients among the tested cultivars have been related to seed vigor with seedling length and dry weight of radicle with seedling with 0.92 and 0.90, respectively.

Influence of Ventilation Strategies and Anesthetic Techniques on Regional Cerebral Oximetry in the Beach Chair Position: A Prospective Interventional Study with a Randomized Comparison of Two Anesthetics.

Science.gov (United States)

Picton, Paul; Dering, Andrew; Alexander, Amir; Neff, Mary; Miller, Bruce S; Shanks, Amy; Housey, Michelle; Mashour, George A

2015-10-01

Beach chair positioning during general anesthesia is associated with cerebral oxygen desaturation. Changes in cerebral oxygenation resulting from the interaction of inspired oxygen fraction (FIO2), end-tidal carbon dioxide (PETCO2), and anesthetic choice have not been fully evaluated in anesthetized patients in the beach chair position. This is a prospective interventional within-group study of patients undergoing shoulder surgery in the beach chair position that incorporated a randomized comparison between two anesthetics. Fifty-six patients were randomized to receive desflurane or total intravenous anesthesia with propofol. Following induction of anesthesia and positioning, FIO2 and minute ventilation were sequentially adjusted for all patients. Regional cerebral oxygenation (rSO2) was the primary outcome and was recorded at each of five set points. While maintaining FIO2 at 0.3 and PETCO2 at 30 mmHg, there was a decrease in rSO2 from 68% (SD, 12) to 61% (SD, 12) (P positioning. The combined interventions of increasing FIO2 to 1.0 and increasing PETCO2 to 45 mmHg resulted in a 14% point improvement in rSO2 to 75% (SD, 12) (P position. There was no significant interaction effect of the anesthetic at the study intervention points. Increasing FIO2 and PETCO2 resulted in a significant increase in rSO2 that overcomes desaturation in patients anesthetized in the beach chair position and that appears independent of anesthetic choice.

THE CONTRIBUTION OF 'RESTING' BODY MUSCLES TO THE SLOW COMPONENT OF PULMONARY OXYGEN UPTAKE DURING HIGH-INTENSITY CYCLING

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Susan A. Ward

2012-12-01

Full Text Available Oxygen uptake (VO2 kinetics during moderate constant- workrate (WR exercise (>lactate-threshold (ӨL are well described as exponential. AboveӨL, these kinetics are more complex, consequent to the development of a delayed slow component (VO2sc, whose aetiology remains controversial. To assess the extent of the contribution to the VO2sc from arm muscles involved in postural stability during cycling, six healthy subjects completed an incremental cycle-ergometer test to the tolerable limit for estimation of ӨL and determination of peak VO2. They then completed two constant-WR tests at 90% of ӨL and two at 80% of ∆ (difference between ӨL and VO2peak. Gas exchange variables were derived breath-by-breath. Local oxygenation profiles of the vastus lateralis and biceps brachii muscles were assessed by near-infrared spectroscopy, with maximal voluntary contractions (MVC of the relevant muscles being performed post-exercise to provide a frame of reference for normalising the exercise-related oxygenation responses across subjects. Above supra-ӨL, VO2 rose in an exponential-like fashion ("phase 2, with a delayed VO2sc subsequently developing. This was accompanied by an increase in [reduced haemoglobin] relative to baseline (∆[Hb], which attained 79 ± 13 % (mean, SD of MVC maximum in vastus lateralis at end-exercise and 52 ± 27 % in biceps brachii. Biceps brachii ∆[Hb] was significantly correlated with VO2 throughout the slow phase. In contrast, for sub- L exercise, VO2 rose exponentially to reach a steady state with a more modest increase in vastus lateralis ∆[Hb] (30 ± 11 %; biceps brachii ∆[Hb] was minimally affected (8 ± 2 %. That the intramuscular O2 desaturation profile in biceps brachii was proportional to that for VO2sc during supra-ӨL cycle ergometry is consistent with additional stabilizing arm work contributing to the VO2sc

Singlet oxygen quenching by oxygen in tetraphenyl-porphyrin solutions

International Nuclear Information System (INIS)

Dedic, Roman; Korinek, Miloslav; Molnar, Alexander; Svoboda, Antonin; Hala, Jan

2006-01-01

Time-resolved measurement of singlet oxygen infrared phosphorescence is a powerful tool for determination of quantum yields and kinetics of its photosensitization. This technique was employed to investigate in detail the previously observed effect of singlet oxygen quenching by oxygen. The question whether the singlet oxygen is quenched by oxygen in ground or in excited state was addressed by study of two complementary dependencies of singlet oxygen lifetimes: on dissolved oxygen concentration and on excitation intensity. Oxygen concentration dependence study of meso-tetra(4-sulphonato)phenylporphyrin (TPPS 4 ) phosphorescence kinetics showed linearity of the dependence of TPPS 4 triplet state rate-constant. Corresponding bimolecular quenching constant of (1.5±0.1)x10 9 l/mol s was obtained. On the other hand, rate constants of singlet oxygen depopulation exhibit nonlinear dependence on oxygen concentration. Comparison of zero oxygen concentration-extrapolated value of singlet oxygen lifetime of (6.5±0.4) μs to (3.7±0.1) μs observed under air-saturated conditions indicates importance of the effect of quenching of singlet oxygen by oxygen. Upward-sloping dependencies of singlet oxygen depopulation rate-constant on excitation intensity evidence that singlet oxygen is predominantly quenched by oxygen in excited singlet state

Quantification of circulating cell-free DNA in the serum of patients with obstructive sleep apnea-hypopnea syndrome.

Science.gov (United States)

Ye, Liang; Ma, Guan-Hua; Chen, Ling; Li, Min; Liu, Jia-Lin; Yang, Kun; Li, Qing-Yun; Li, Ning; Wan, Huan-Ying

2010-12-01

Serum cell-free DNA concentrations have been reported to increase in many acute diseases as well as in some chronic conditions such as cancer and autoimmune diseases. The aim of this study was to examine whether serum DNA concentrations were elevated in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). The effects of nasal continuous positive airway pressure (nCPAP) on serum DNA were also investigated. One hundred twenty-seven people diagnosed with OSAHS by polysomnography (PSG) were admitted into the OSAHS group, and 52 subjects without OSAHS were recruited for the control group. The OSAHS group was further divided into mild, moderate, and severe OSAHS subgroups based on their apnea-hypopnea index (AHI) during sleep. Ten patients with moderate and severe OSAHS were treated with nCPAP. Serum DNA, interleukin-6 (IL-6), and malonaldehyde (MDA) concentrations were measured and were found to be significantly higher in patients with moderate and severe OSAHS groups than those in the mild OSAHS and control groups (p DNA correlated positively with AHI, oxygen desaturation index (ODI), IL-6, and MDA, and negatively correlated with minimal oxygen saturation (miniSaO(2)) (all p DNA concentrations. After 6 months of nCPAP therapy, serum concentrations of DNA, IL-6, and MDA were significantly decreased (p DNA in patients with OSAHS was positively correlated with disease severity. Serum DNA may become an important parameter for monitoring the severity of OSAHS and effectiveness of therapy.

Long-Term Experience with First-Generation Implantable Neurostimulation Device in Central Sleep Apnea Treatment.

Science.gov (United States)

Fox, Henrik; Bitter, Thomas; Horstkotte, Dieter; Oldenburg, Olaf; Gutleben, Klaus-Jürgen

2017-05-01

Sleep-disordered breathing (SDB) and Cheyne-Stokes respiration (CSR) are associated with shorter survival in patients with heart failure. A novel treatment method for this patient group is unilateral phrenic nerve stimulation by the remedē® system (Respicardia Inc., Minnetonka, MN, USA), a transvenously implantable neurostimulation device, which has recently been studied in a large randomized, controlled trial. Previous literature has shown efficacy and safety of the treatment with this first-generation device, but hardly any data are available on long-term clinical parameters, the remedē® device's battery lifetime, device exchangeability, lead position stability, surgical accessibility, and manageability. We performed remedē® device replacements in consecutive patients for battery depletion, and documented clinical parameters, longevity, operation procedure, complications, and difficulties. All patients were on neurostimulation treatment by phrenic nerve neurostimulation when device replacement became necessary. Apnea-hypopnea index (from 45 ± 4/h to 9 ± 4/h), oxygen-desaturation index (from 35 ± 7/h to 7 ± 6/h), and time spent with oxygen saturation of ray documentation of stable lead positions in a long-term setting, no radiation or contrast dye usage was needed and no major complications occurred. In addition, clinical exercise capacity and sleepiness symptoms improved. Novel remedē® device shows sustained therapy efficacy and safety in terms of stable lead positions over 4 years. Long-term phrenic nerve neurostimulation therapy for central SDB/CSR appears feasible in a clinical routine setting. © 2017 Wiley Periodicals, Inc.

Evaluation of water quality index for River Sabarmati, Gujarat, India

Science.gov (United States)

Shah, Kosha A.; Joshi, Geeta S.

2017-06-01

An attempt has been made to develop water quality index (WQI), using six water quality parameters pH, dissolved oxygen, biochemical oxygen demand, electrical conductivity, nitrate nitrogen and total coliform measured at three different stations along the Sabarmati river basin from the year 2005 to 2008. Rating scale is developed based on the tolerance limits of inland waters and health point of view. Weighted arithmetic water quality index method was used to find WQI along the stretch of the river basin. It was observed from this study that the impact of human activity and sewage disposal in the river was severe on most of the parameters. The station located in highly urban area showed the worst water quality followed by the station located in moderately urban area and lastly station located in a moderately rural area. It was observed that the main cause of deterioration in water quality was due to the high anthropogenic activities, illegal discharge of sewage and industrial effluent, lack of proper sanitation, unprotected river sites and urban runoff.

THE CONDITION INDEX OF MUSSELS (Mytilus galloprovincialis IN BUDAVA AND RAŠA BAY

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Nives Marušić

2009-07-01

Full Text Available Condition index is a factor that can show of some area for shellfish cultivation. Analysis of the condition index from various sites may show importance of these sites for cultivation and shellfish during the year. By monitoring the condition index it is possible to determine dynamic of meat amount change in time. Condition index depends on mussel spawning period, presence of food and changes of environmental factors (temperature, salinity, concentration of dissolved oxygen. The research of condition index was monitored in Budava and Ra{a Bay at depth of 0.5 and 2.5 m. In summer months (July and August when the sea water temperature and salinity were in optimum, the mussel condition index had maximum value. Value of the condition index is proportional with sea temperature and salinity. The condition index of mussels significantly changed over the year period, at different sites (Budava and Raška Bay and at different depth (0.5 and 2.5 m.

Usefulness of the 6-minute walk test as a screening test for pulmonary arterial enlargement in COPD

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Oki Y

2016-11-01

Full Text Available Yutaro Oki,1,2 Masahiro Kaneko,3 Yukari Fujimoto,1 Hideki Sakai,2 Shogo Misu,1,2 Yuji Mitani,1,4 Takumi Yamaguchi,1,2 Hisafumi Yasuda,1 Akira Ishikawa1 1Department of Community Health Sciences, Kobe University Graduate School of Health Sciences, 2Department of Rehabilitation, 3Department of Respiratory Medicine, Kobe City Medical Center West Hospital, Kobe, 4Department of Rehabilitation, Sapporo Nishimaruyama Hospital, Sapporo, Japan Purpose: Pulmonary hypertension and exercise-induced oxygen desaturation (EID influence acute exacerbation of COPD. Computed tomography (CT-detected pulmonary artery (PA enlargement is independently associated with acute COPD exacerbations. Associations between PA to aorta (PA:A ratio and EID in patients with COPD have not been reported. We hypothesized that the PA:A ratio correlated with EID and that results of the 6-minute walk test (6MWT would be useful for predicting the risk associated with PA:A >1.Patients and methods: We retrospectively measured lung function, 6MWT, emphysema area, and PA enlargement on CT in 64 patients with COPD. The patients were classified into groups with PA:A ≤1 and >1. Receiver-operating characteristic curves were used to determine the threshold values with the best cutoff points to predict patients with PA:A >1.Results: The PA:A >1 group had lower forced expiratory volume in 1 second (FEV1, forced vital capacity (FVC, FEV1:FVC ratio, diffusion capacity of lung carbon monoxide, 6MW distance, and baseline peripheral oxygen saturation (SpO2, lowest SpO2, highest modified Borg scale results, percentage low-attenuation area, and history of acute COPD exacerbations ≤1 year, and worse BODE (Body mass index, airflow Obstruction, Dyspnea, and Exercise index results (P<0.05. Predicted PA:A >1 was determined for SpO2 during 6MWT (best cutoff point 89%, area under the curve 0.94, 95% confidence interval 0.88–1. SpO2 <90% during 6MWT showed a sensitivity of 93.1, specificity of 94

Frequency of apnea, bradycardia, and desaturations following first diphtheria-tetanus-pertussis-inactivated polio-Haemophilus influenzae type B immunization in hospitalized preterm infants

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Spady Donald W

2006-06-01

Full Text Available Abstract Background Adverse cardiorespiratory events including apnea, bradycardia, and desaturations have been described following administration of the first diphtheria-tetanus-pertussis-inactivated polio-Haemophilus influenzae type B (DTP-IPV-Hib immunization to preterm infants. The effect of the recent substitution of acellular pertussis vaccine for whole cell pertussis vaccine on the frequency of these events requires further study. Methods Infants with gestational age of ≤ 32 weeks who received their first DTP-IPV-Hib immunization prior to discharge from two Edmonton Neonatal Intensive Care Units January 1, 1996 to November 30, 2000 were eligible for the study. Each immunized infant was matched by gestational age to one control infant. The number of episodes of apnea, bradycardia, and/or desaturations (ABD and the treatment required for these episodes in the 72 hours prior to and 72 hours post-immunization (for the immunized cohort or at the same post-natal age (for controls was recorded. Results Thirty-four infants who received DTP-IPV-Hib with whole cell pertussis vaccine, 90 infants who received DTP-IPV-Hib with acellular pertussis vaccine, and 124 control infants were entered in the study. Fifty-six immunized infants (45.1% and 36 control infants (29.0% had a resurgence of or increased ABD in the 72 hours post-immunization in the immunized infants and at the same post-natal age in the controls with an adjusted odds ratio for immunized infants of 2.41 (95% CI 1.29,4.51 as compared to control infants. The incidence of an increase in adverse cardiorespiratory events post-immunization was the same in infants receiving whole cell or acellular pertussis vaccine (44.1% versus 45.6%. Eighteen immunized infants (14.5% and 51 control infants (41.1% had a reduction in ABD in the 72 hours post- immunization or at the equivalent postnatal age in controls for an odds ratio of 0.175 (95%CI 0.08, 0.39. The need for therapy of ABD in the immunized

Frequency of apnea, bradycardia, and desaturations following first diphtheria-tetanus-pertussis-inactivated polio-Haemophilus influenzae type B immunization in hospitalized preterm infants

Science.gov (United States)

Lee, Jackie; Robinson, Joan L; Spady, Donald W

2006-01-01

Background Adverse cardiorespiratory events including apnea, bradycardia, and desaturations have been described following administration of the first diphtheria-tetanus-pertussis-inactivated polio-Haemophilus influenzae type B (DTP-IPV-Hib) immunization to preterm infants. The effect of the recent substitution of acellular pertussis vaccine for whole cell pertussis vaccine on the frequency of these events requires further study. Methods Infants with gestational age of ≤ 32 weeks who received their first DTP-IPV-Hib immunization prior to discharge from two Edmonton Neonatal Intensive Care Units January 1, 1996 to November 30, 2000 were eligible for the study. Each immunized infant was matched by gestational age to one control infant. The number of episodes of apnea, bradycardia, and/or desaturations (ABD) and the treatment required for these episodes in the 72 hours prior to and 72 hours post-immunization (for the immunized cohort) or at the same post-natal age (for controls) was recorded. Results Thirty-four infants who received DTP-IPV-Hib with whole cell pertussis vaccine, 90 infants who received DTP-IPV-Hib with acellular pertussis vaccine, and 124 control infants were entered in the study. Fifty-six immunized infants (45.1%) and 36 control infants (29.0%) had a resurgence of or increased ABD in the 72 hours post-immunization in the immunized infants and at the same post-natal age in the controls with an adjusted odds ratio for immunized infants of 2.41 (95% CI 1.29,4.51) as compared to control infants. The incidence of an increase in adverse cardiorespiratory events post-immunization was the same in infants receiving whole cell or acellular pertussis vaccine (44.1% versus 45.6%). Eighteen immunized infants (14.5%) and 51 control infants (41.1%) had a reduction in ABD in the 72 hours post- immunization or at the equivalent postnatal age in controls for an odds ratio of 0.175 (95%CI 0.08, 0.39). The need for therapy of ABD in the immunized infants was not

Influence of perioperative oxygen fraction on pulmonary function after abdominal surgery: a randomized controlled trial

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Staehr Anne K

2012-07-01

Full Text Available Abstract Background A high perioperative inspiratory oxygen fraction (FiO2 may reduce the frequency of surgical site infection. Perioperative atelectasis is caused by absorption, compression and reduced function of surfactant. It is well accepted, that ventilation with 100% oxygen for only a few minutes is associated with significant formation of atelectasis. However, it is still not clear if a longer period of 80% oxygen results in more atelectasis compared to a low FiO2. Our aim was to assess if a high FiO2 is associated with impaired oxygenation and decreased pulmonary functional residual capacity (FRC. Methods Thirty-five patients scheduled for laparotomy for ovarian cancer were randomized to receive either 30% oxygen (n = 15 or 80% oxygen (n = 20 during and for 2 h after surgery. The oxygenation index (PaO2/FiO2 was measured every 30 min during anesthesia and 90 min after extubation. FRC was measured the day before surgery and 2 h after extubation by a rebreathing method using the inert gas SF6. Results Five min after intubation, the median PaO2/FiO2 was 69 kPa [53-71] in the 30%-group vs. 60 kPa [47-69] in the 80%-group (P = 0.25. At the end of anesthesia, the PaO2/FiO2 was 58 kPa [40-70] vs. 57 kPa [46-67] in the 30%- and 80%-group, respectively (P = 0.10. The median FRC was 1993 mL [1610-2240] vs. 1875 mL [1545-2048] at baseline and 1615 mL [1375-2318] vs. 1633 mL [1343-1948] postoperatively in the 30%- and 80%-group, respectively (P = 0.70. Conclusion We found no significant difference in oxygenation index or functional residual capacity between patients given 80% and 30% oxygen for a period of approximately 5 hours. Trial registration ClinicalTrials.gov Identifier: NCT00637936.

The refractive index of human hemoglobin in the visible range

International Nuclear Information System (INIS)

Zhernovaya, O; Tuchin, V; Sydoruk, O; Douplik, A

2011-01-01

Because the refractive index of hemoglobin in the visible range is sensitive to the hemoglobin concentration, optical investigations of hemoglobin are important for medical diagnostics and treatment. Direct measurements of the refractive index are, however, challenging; few such measurements have previously been reported, especially in a wide wavelength range. We directly measured the refractive index of human deoxygenated and oxygenated hemoglobin for nine wavelengths between 400 and 700 nm for the hemoglobin concentrations up to 140 g l -1 . This paper analyzes the results and suggests a set of model functions to calculate the refractive index depending on the concentration. At all wavelengths, the measured values of the refractive index depended on the concentration linearly. Analyzing the slope of the lines, we determined the specific refraction increments, derived a set of model functions for the refractive index depending on the concentration, and compared our results with those available in the literature. Based on the model functions, we further calculated the refractive index at the physiological concentration within the erythrocytes of 320 g l -1 . The results can be used to calculate the refractive index in the visible range for arbitrary concentrations provided that the refractive indices depend on the concentration linearly.

Sleep-related disorders in chronic obstructive pulmonary disease.

LENUS (Irish Health Repository)

Crinion, Sophie J

2014-02-01

Sleep may have several negative consequences in patients with chronic obstructive pulmonary disease (COPD). Sleep is typically fragmented with diminished slow wave and rapid-eye-movement sleep, which likely represents an important contributing factor to daytime symptoms such as fatigue and lethargy. Furthermore, normal physiological adaptations during sleep, which result in mild hypoventilation in normal subjects, are more pronounced in COPD, which can result in clinically important nocturnal oxygen desaturation. The co-existence of obstructive sleep apnea and COPD is also common, principally because of the high prevalence of each disorder, and there is little convincing evidence that one disorder predisposes to the other. Nonetheless, this co-existence, termed the overlap syndrome, typically results in more pronounced nocturnal oxygen desaturation and there is a high prevalence of pulmonary hypertension in such patients. Management of sleep disorders in patients with COPD should address both sleep quality and disordered gas exchange. Non-invasive pressure support is beneficial in selected cases, particularly during acute exacerbations associated with respiratory failure, and is particularly helpful in patients with the overlap syndrome. There is limited evidence of benefit from pressure support in the chronic setting in COPD patients without obstructive sleep apnea.

Decline in arterial partial pressure of oxygen after exercise: a surrogate marker of pulmonary vascular obstructive disease in patients with atrial septal defect and severe pulmonary hypertension.

Science.gov (United States)

Laksmivenkateshiah, Srinivas; Singhi, Anil K; Vaidyanathan, Balu; Francis, Edwin; Karimassery, Sundaram R; Kumar, Raman K

2011-06-01

To examine the utility of decline in arterial partial pressure of oxygen after exercise as a marker of pulmonary vascular obstructive disease in patients with atrial septal defect and pulmonary hypertension. Treadmill exercise was performed in 18 patients with atrial septal defect and pulmonary hypertension. Arterial blood gas samples were obtained before and after peak exercise. A decline in the arterial pressure of oxygen of more than 10 millimetres of mercury after exercise was considered significant based on preliminary tests conducted on the controls. Cardiac catheterisation was performed in all patients and haemodynamic data sets were obtained on room air, oxygen, and a mixture of oxygen and nitric oxide (30-40 parts per million). There were 10 patients who had more than a 10 millimetres of mercury drop in arterial partial pressure of oxygen after exercise and who had a basal pulmonary vascular resistance index of more than 7 Wood units per square metre. Out of eight patients who had less than a 10 millimetres of mercury drop in arterial partial pressure of oxygen after exercise, seven had a basal pulmonary vascular resistance index of less than 7 Wood units per square metre, p equals 0.0001. A decline in arterial partial pressure of oxygen of more than 10 millimetres of mercury predicted a basal pulmonary vascular resistance index of more than 7 Wood units per square metre with a specificity of 100% and a sensitivity of 90%. A decline in arterial partial pressure of oxygen following exercise appears to predict a high pulmonary vascular resistance index in patients with atrial septal defect and pulmonary hypertension. This test is a useful non-invasive marker of pulmonary vascular obstructive disease in this subset.

Chronic obstructive pulmonary disease and obstructive sleep apnea: overlaps in pathophysiology, systemic inflammation, and cardiovascular disease.

LENUS (Irish Health Repository)

McNicholas, Walter T

2012-02-01

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea syndrome represent two of the most prevalent chronic respiratory disorders in clinical practice, and cardiovascular diseases represent a major comorbidity in each disorder. The two disorders coexist (overlap syndrome) in approximately 1% of adults but asymptomatic lower airway obstruction together with sleep-disordered breathing is more prevalent. Although obstructive sleep apnea syndrome has similar prevalence in COPD as the general population, and vice versa, factors such as body mass index and smoking influence relationships. Nocturnal oxygen desaturation develops in COPD, independent of apnea\\/hypopnea, and is more severe in the overlap syndrome, thus predisposing to pulmonary hypertension. Furthermore, upper airway flow limitation contributes to nocturnal desaturation in COPD without apnea\\/hypopnea. Evidence of systemic inflammation in COPD and sleep apnea, involving C-reactive protein and IL-6, in addition to nuclear factor-kappaB-dependent pathways involving tumor necrosis factor-alpha and IL-8, provides insight into potential basic interactions between both disorders. Furthermore, oxidative stress develops in each disorder, in addition to activation and\\/or dysfunction of circulating leukocytes. These findings are clinically relevant because systemic inflammation may contribute to the pathogenesis of cardiovascular diseases and the cell\\/molecular pathways involved are similar to those identified in COPD and sleep apnea. However, the pathophysiological and clinical significance of systemic inflammation in COPD and sleep apnea is not proven, and thus, studies of patients with the overlap syndrome should provide insight into the mechanisms of systemic inflammation in COPD and sleep apnea, in addition to potential relationships with cardiovascular disease.

The Evolution of Deepwater Dissolved Oxygen in the Northern South China Sea During the Past 400 ka

Science.gov (United States)

Wang, N.; Huang, B.; Dong, Y.

2016-12-01

Reconstruction of dissolved oxygen in paleo-ocean contributes toward understanding the history of ocean circulation, climate, causes of extinctions, and the evolution of marine organisms. Based on analysis of benthic foraminifera oxygen index (BFOI), the redox-sensitive trace elements (Mo/Al), the percentage of epifaunal benthic foraminifera and infaunal/epifaunal ratio at core MD12-3432, we reconstruct the evolution of deep water dissolved oxygen in northern South China Sea (SCS) during the past 400 ka and discuss the mechanisms of variable dissolved oxygen. Both BFOI and Mo/Al are redox indicators. Similar trends confirm that they reflect the variation of dissolved oxygen in seawater since 400 ka accurately. BFOI and Mo/Al indicate that dissolved oxygen was high in MIS 11-MIS 7 and decreased gradually during MIS 6- MIS 2. The percentage of epifauna decreased and infaunal/epifaunal ratio increased with decreasing dissolved oxygen. By comparison of dissolved oxygen and productivity indexes such as phytoplankton total (PT) and species abundances, we found that when PT fluctuated in the average range of 1000-1500 ng/g, the abundances of Bulimina and Uvigerina which represent high productivity increased. However, when PT reached the range of 2500-3000 ng/g, the abundances of Bulimina and Uvigerina didn't increase, but the abundances of dysoxic species Chilostomella oolina and Globobulimina pacifica increased and the dissolved oxygen reached low value. The reasons may be that the decomposition of excessive organic matter consumed more dissolved oxygen. The low dissolved oxygen suppressed the growth of Bulimina and Uvigerina and accelerated the boom of C. oolina and G. oolina. The dissolved oxygen is not only associated with productivity, but also affected by the thermohaline circulation. Benthic foraminifera F. favus is the representative species in Pacific deep water. Its appearance at 194 ka, 205 ka, 325, the 328 ka in MD12-3432 indicate that the upper border of

Assessment of Aeromedical Evacuation Transport Patient Outcomes With and Without Cabin Altitude Restriction

Science.gov (United States)

2017-08-24

adverse events occurred in cardiac patients; most of the events required supplemental oxygen due to the development of chest pain . The adverse clinical...5.48, p = 0.02), but only 3 were clinically relevant—1 chest pain (CAR) and 3 desaturations (non-CAR). Appendix C contains additional PMQR...Supplemental Patient Diagnosis Information Diagnoses at Discharge (outcomes) CAR Non-CAR Head & Neck (including cervical spine) • Fatal head

'Multi-associations': predisposed to misinterpretation of peripheral tissue oxygenation and circulation in neonates.

Science.gov (United States)

Pichler, Gerhard; Pocivalnik, Mirjam; Riedl, Regina; Pichler-Stachl, Elisabeth; Morris, Nicholas; Zotter, Heinz; Müller, Wilhelm; Urlesberger, Berndt

2011-08-01

Interpretation of peripheral circulation in ill neonates is crucial but difficult. The aim was to analyse parameters potentially influencing peripheral oxygenation and circulation. In a prospective observational cohort study in 116 cardio-circulatory stable neonates, peripheral muscle near-infrared spectroscopy (NIRS) with venous occlusion was performed. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO(2)), fractional oxygen extraction (FOE), fractional tissue oxygen extraction (FTOE), haemoglobin flow (Hbflow), oxygen delivery (DO(2)), oxygen consumption (VO(2)), and vascular resistance (VR) were assessed. Correlation coefficients between NIRS parameters and demographic parameters (gestational age, birth weight, age, actual weight, diameter of calf, subcutaneous adipose tissue), monitoring parameters (heart rate, arterial oxygen saturation (SaO(2)), mean blood pressure (MAP), core/peripheral temperature, central/peripheral capillary refill time) and laboratory parameters (haemoglobin concentration (Hb-blood), pCO(2)) were calculated. All demographic parameters except for Hbflow and DO(2) correlated with NIRS parameters. Heart rate correlated with TOI, SvO(2), VO(2) and VR. SaO(2) correlated with FOE/FTOE. MAP correlated with Hbflow, DO(2), VO(2) and VR. Core temperature correlated with FTOE. Peripheral temperature correlated with all NIRS parameters except VO(2). Hb-blood correlated with FOE and VR. pCO(2) levels correlated with TOI and SvO(2). The presence of multiple interdependent factors associated with peripheral oxygenation and circulation highlights the difficulty in interpreting NIRS data. Nevertheless, these findings have to be taken into account when analysing peripheral oxygenation and circulation data.

water quality index estimate for isiodu river water during dredging in ...

African Journals Online (AJOL)

user

BOD5), dissolved oxygen (DO) ... quality index are fecal coliform count (6.96, 7.57mg/L), BOD5 (3.21, 3.17mg/L) DO (5.47, 5.36mg/L), pH (6.87, 6.86), temperature (13.20 ... Stations A and B are found upstream relative to the dredger position C,.

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

Normobaric hypoxia inhalation test vs. response to airline flight in healthy passengers.

Science.gov (United States)

Kelly, Paul T; Swanney, Maureen P; Frampton, Chris; Seccombe, Leigh M; Peters, Matthew J; Beckert, Lutz E

2006-11-01

There is little data available to determine the normal response to normobaric hypoxia inhalation testing (NHIT) and air travel. Quantifying a healthy response may assist in the evaluation of passengers considered at risk for air travel. The aims of this study were: (1) to quantify the degree of desaturation in healthy subjects during a NHIT and air travel; and (2) assess the validity of the NHIT when compared with actual in-flight responses. There were 15 healthy adults (age 23-57; 10 women) who volunteered for this study. Preflight tests included lung function, arterial blood gas, pulse oximetry (SpO2), and NHIT (inspired oxygen 15%). SpO2 and cabin pressure were measured continuously on each subject during a commercial air flight (mean cabin altitude 2178 m; range 1719-2426 m). In-flight oxygenation was compared with the preflight NHIT. Lung function testing results were normal. There was significant desaturation (SpO2) during the NHIT (pre: 98 +/- 2%; post: 92 +/- 2%) and at cruising altitude (pre: 97 +/- 1%; cruise: 92 +/- 2%). There was no difference between the final NHIT SpO2 and the mean in-flight SpO2. There was a significant difference between the lowest in-flight SpO2 (88 +/- 2%) vs. the lowest NHIT SpO2, (90 +/- 2%). Oxygen saturation decreases significantly during air travel in normal individuals. In this group of healthy passengers the NHIT approximates some, but not all, aspects of in-flight oxygenation. These results can be used to describe a normal response to the NHIT and air-travel.

Oxygen, climate and the chemical evolution of a 1400 million year old tropical marine setting

DEFF Research Database (Denmark)

Wang, Xiaomei; Zhang, Shuichang; Wang, Huajian

2017-01-01

by oxygenated bottom waters. The transition to unit 3 reflects an increase in primary productivity, and the development of a more biologically active OMZ, that supported anoxygenic phototrophic bacteria. Still, in this unit, the bottom waters remained oxygenated. The overlying unit 2 represents the transition...... for the iron. However, the low organic carbon contents, low hydrogen index (HI) values, and the oxidized nature of the reactive iron pool indicate deposition in oxygenated bottom waters. We interpret unit 4 to represent a low-productivity ferruginous oxygen-minimum zone (OMZ) environment, underlain......The Xiamaling Formation is an exceptionally well-preserved sedimentary succession deposited on a marine passive margin about 1400 million years ago. We used a multi-proxy approach, including iron speciation, trace metal dynamics, and organic geochemistry, to explore the evolution of ocean chemistry...

Evolution of phenolic compounds and astringency during aging of red wine: effect of oxygen exposure before and after bottling.

Science.gov (United States)

Gambuti, Angelita; Rinaldi, Alessandra; Ugliano, Maurizio; Moio, Luigi

2013-02-27

The aim of this study was to evaluate the effect of oxygen exposure of red wine, before (micro-oxygenation) and after (nano-oxygenation) bottling, on the phenolic composition and astringency of wine. The astringency was evaluated by sensory analysis and by a method based on the SDS-PAGE of salivary proteins after reaction of saliva with wine (SPI, saliva precipitation index). Micro-oxygenation caused a stabilization of color, but this effect disappeared after long aging. For the wine with the lower pH a decrease of wine astringency and SPI was observed 42 months after micro-oxygenation. Oxygen ingress through the closure postbottling was positively correlated with the decrease of SPI. Therefore, the astringency and reactivity of wines toward salivary proteins of a bottled red wine can be modulated by controlled oxygen exposure during aging. For both experiments the effect of oxygen exposure depended on wine composition.

Oxygen toxicity

Directory of Open Access Journals (Sweden)

C. A. van der Westhuizen

1990-07-01

Full Text Available Oxygen has been discovered about 200 years ago. Since then the vital physiological involvement of oxygen in various biologi­cal processes, mainly energy production, has been established. However, in the body molecular oxygen can be converted to toxic oxygen metabolites such as superoxide anion, hydrogen peroxide, the hydroxyl radical and singlet oxygen. These toxic metabolites are produced mainly in the mitochondria, plasma membranes and endoplasmic reticulum.

An analysis of decrements in vital capacity as an index of pulmonary oxygen toxicity.

Science.gov (United States)

Harabin, A L; Homer, L D; Weathersby, P K; Flynn, E T

1987-09-01

Decrements in vital capacity (% delta VC) were proposed by the Pennsylvania group in the early 1970s as an index of O2-induced lung damage. These workers used the combined effects of PO2 and time of exposure to develop recommendations to limit expected % delta VC. Adopting this general approach, we fitted human pulmonary O2 toxicity data to the hyperbolic equation % delta VC = Bs.(PO2 - B1).(time)B3 using a nonlinear least squares analysis. In addition to the data considered in 1970, our analysis included new data available from the literature. The best fit was obtained when 1) an individual slope parameter, Bs, was estimated for each subject instead of an average slope; 2) PO2 asymptote B1 = 0.38 ATA; and 3) exponent B3 = 1.0. Wide individual variation imposed large uncertainty on any % delta VC prediction. A 12-h exposure to a PO2 of 1 ATA would be expected to yield a median VC decrement of 4%. The 80% confidence limits, however, included changes from +1.0 and -12% delta VC. Until an improved index of pulmonary O2 toxicity is developed, a simplified expression % delta VC = -0.011.(PO2 - 0.5).time (PO2 in ATA and time in min) can be used to predict a median response with little loss in predictability. The limitations of changes in VC as an index are discussed.

Mixed oxygen ion/electron-conducting ceramics for oxygen separation

Energy Technology Data Exchange (ETDEWEB)

Stevenson, J.W.; Armstrong, T.R.; Armstrong, B.L. [Pacific Northwest National Lab., Richland, WA (United States)

1996-08-01

Mixed oxygen ion and electron-conducting ceramics are unique materials that can passively separate high purity oxygen from air. Oxygen ions move through a fully dense ceramic in response to an oxygen concentration gradient, charge-compensated by an electron flux in the opposite direction. Compositions in the system La{sub 1{minus}x}M{sub x}Co{sub 1{minus}y{minus}z}Fe{sub y}N{sub z}O{sub 3{minus}{delta}}, perovskites where M=Sr, Ca, and Ba, and N=Mn, Ni, Cu, Ti, and Al, have been prepared and their electrical, oxygen permeation, oxygen vacancy equilibria, and catalytic properties evaluated. Tubular forms, disks, and asymmetric membrane structures, a thin dense layer on a porous support of the same composition, have been fabricated for testing purposes. In an oxygen partial gradient, the passive oxygen flux through fully dense structures was highly dependent on composition. An increase in oxygen permeation with increased temperature is attributed to both enhanced oxygen vacancy mobility and higher vacancy populations. Highly acceptor-doped compositions resulted in oxygen ion mobilities more than an order of magnitude higher than yttria-stabilized zirconia. The mixed conducting ceramics have been utilized in a membrane reactor configuration to upgrade methane to ethane and ethylene. Conditions were established to balance selectivity and throughput in a catalytic membrane reactor constructed from mixed conducting ceramics.

Functional and biocompatibility performances of an integrated Maglev pump-oxygenator.

Science.gov (United States)

Zhang, Tao; Cheng, Guangming; Koert, Andrew; Zhang, Juntao; Gellman, Barry; Yankey, G Kwame; Satpute, Aditee; Dasse, Kurt A; Gilbert, Richard J; Griffith, Bartley P; Wu, Zhongjun J

2009-01-01

To provide respiratory support for patients with lung failure, a novel compact integrated pump-oxygenator is being developed. The functional and biocompatibility performances of this device are presented. The pump-oxygenator is designed by combining a magnetically levitated pump/rotor with a uniquely configured hollow fiber membrane bundle to create an assembly free, ultracompact, all-in-one system. The hemodynamics, gas transfer and biocompatibility performances of this novel device were investigated both in vitro in a circulatory flow loop and in vivo in an ovine animal model. The in vitro results showed that the device was able to pump blood flow from 2 to 8 L/min against a wide range of pressures and to deliver an oxygen transfer rate more than 300 mL/min at a blood flow of 6 L/min. Blood damage tests demonstrated low hemolysis (normalized index of hemolysis [NIH] approximately 0.04) at a flow rate of 5 L/min against a 100-mm Hg afterload. The data from five animal experiments (4 h to 7 days) demonstrated that the device could bring the venous blood to near fully oxygen-saturated condition (98.6% +/- 1.3%). The highest oxygen transfer rate reached 386 mL/min. The gas transfer performance was stable over the study duration for three 7-day animals. There was no indication of blood damage. The plasma free hemoglobin and platelet count were within the normal ranges. No gross thrombus is found on the explanted pump components and fiber surfaces. Both in vitro and in vivo results demonstrated that the newly developed pump-oxygenator can achieve sufficient blood flow and oxygen transfer with excellent biocompatibility.

Cerebral blood flow and metabolism during exercise: implications for fatigue

DEFF Research Database (Denmark)

Seifert, T.; Lieshout, J.J. van; Secher, Niels

2008-01-01

During exercise: the Kety-Schmidt-determined cerebral blood flow (CBF) does not change because the jugular vein is collapsed in the upright position. In contrast, when CBF is evaluated by (133)Xe clearance, by flow in the internal carotid artery, or by flow velocity in basal cerebral arteries......, a approximately 25% increase is detected with a parallel increase in metabolism. During activation, an increase in cerebral O(2) supply is required because there is no capillary recruitment within the brain and increased metabolism becomes dependent on an enhanced gradient for oxygen diffusion. During maximal...... whole body exercise, however, cerebral oxygenation decreases because of eventual arterial desaturation and marked hyperventilation-related hypocapnia of consequence for CBF. Reduced cerebral oxygenation affects recruitment of motor units, and supplemental O(2) enhances cerebral oxygenation and work...

Effect of thoracic epidural anesthesia on oxygen delivery and utilization in cardiac surgical patients scheduled to undergo off-pump coronary artery bypass surgery: a prospective study.

Science.gov (United States)

Suryaprakash, Sharadaprasad; Chakravarthy, Murali; Gautam, Mamatha; Gandhi, Anurag; Jawali, Vivek; Patil, Thimmannagowda; Jayaprakash, Krishnamoorthy; Pandey, Saurabh; Muniraju, Geetha

2011-01-01

To evaluate the effect of thoracic epidural anesthesia (TEA) on tissue oxygen delivery and utilization in patients undergoing cardiac surgery. This prospective observational study was conducted in a tertiary referral heart hospital. A total of 25 patients undergoing elective off-pump coronary artery bypass surgery were enrolled in this study. All patients received thoracic epidural catheter in the most prominent inter-vertebral space between C7 and T3 on the day before operation. On the day of surgery, an arterial catheter and Swan Ganz catheter (capable of measuring cardiac index) was inserted. After administering full dose of local anesthetic in the epidural space, serial hemodynamic and oxygen transport parameters were measured for 30 minute prior to administration of general anesthesia, with which the study was culminated. A significant decrease in oxygen delivery index with insignificant changes in oxygen extraction and consumption indices was observed. We conclude that TEA does not affect tissue oxygenation despite a decrease in arterial pressures and cardiac output.

Effect of thoracic epidural anesthesia on oxygen delivery and utilization in cardiac surgical patients scheduled to undergo off-pump coronary artery bypass surgery: A prospective study

Directory of Open Access Journals (Sweden)

Suryaprakash Sharadaprasad

2011-01-01

Full Text Available To evaluate the effect of thoracic epidural anesthesia (TEA on tissue oxygen delivery and utilization in patients undergoing cardiac surgery. This prospective observational study was conducted in a tertiary referral heart hospital. A total of 25 patients undergoing elective off-pump coronary artery bypass surgery were enrolled in this study. All patients received thoracic epidural catheter in the most prominent inter-vertebral space between C7 and T3 on the day before operation. On the day of surgery, an arterial catheter and Swan Ganz catheter (capable of measuring cardiac index was inserted. After administering full dose of local anesthetic in the epidural space, serial hemodynamic and oxygen transport parameters were measured for 30 minute prior to administration of general anesthesia, with which the study was culminated. A significant decrease in oxygen delivery index with insignificant changes in oxygen extraction and consumption indices was observed. We conclude that TEA does not affect tissue oxygenation despite a decrease in arterial pressures and cardiac output.

Premature awakening and underuse of neuromuscular monitoring in a registry of patients with butyrylcholinesterase deficiency

DEFF Research Database (Denmark)

Thomsen, J L; Nielsen, C V; Palmqvist, D F

2015-01-01

, neuromuscular monitoring, and postoperative respiratory complications, defined as arterial oxygen desaturation prematurely awakened if anaesthesia had been terminated while the patient was still...... paralysed. RESULTS: We included 123 patients. Neuromuscular monitoring was applied before awakening in 48 (39%) patients. A nerve stimulator was never used or only after attempted awakening in the remaining 75 (61%) patients. Premature awakening occurred in 75 (100%) and 14 (29%) of the unmonitored...

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.

Gastric injury induced by hemorrhage, local ischemia, and oxygen radical generation

International Nuclear Information System (INIS)

Wadhwa, S.S.; Perry, M.A.

1987-01-01

Gastric mucosal injury caused by local intra-arterial generation of oxygen-derived free radicals was compared with gastric injury caused by 30 min of hemorrhage-induced ischemia or local ischemia. The index of injury was the loss of 51 Cr-labeled red cells across the gastric mucosa. Generation of oxygen radicals in the celiac artery caused a rapid increase in mucosal blood loss during the period of radical generation, and this loss was maintained after radical production ceased. Local ischemia produced similar mucosal injury; however, this occurred after reperfusion of the stomach and not during the ischemic episode. Hemorrhage-induced ischemia produced a threefold greater mucosal blood loss than local ischemia. The results of this study indicate that (1) oxygen radicals generated enzymatically in the blood supply to the stomach cause mucosal bleeding of similar magnitude to that observed after local ischemia and (2) that gastric ischemia induced by systemic hypotension produces more severe gastric injury than the same level of local hypotension

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

High-Energy-Density Metal-Oxygen Batteries: Lithium-Oxygen Batteries vs Sodium-Oxygen Batteries.

Science.gov (United States)

Song, Kyeongse; Agyeman, Daniel Adjei; Park, Mihui; Yang, Junghoon; Kang, Yong-Mook

2017-12-01

The development of next-generation energy-storage devices with high power, high energy density, and safety is critical for the success of large-scale energy-storage systems (ESSs), such as electric vehicles. Rechargeable sodium-oxygen (Na-O 2 ) batteries offer a new and promising opportunity for low-cost, high-energy-density, and relatively efficient electrochemical systems. Although the specific energy density of the Na-O 2 battery is lower than that of the lithium-oxygen (Li-O 2 ) battery, the abundance and low cost of sodium resources offer major advantages for its practical application in the near future. However, little has so far been reported regarding the cell chemistry, to explain the rate-limiting parameters and the corresponding low round-trip efficiency and cycle degradation. Consequently, an elucidation of the reaction mechanism is needed for both lithium-oxygen and sodium-oxygen cells. An in-depth understanding of the differences and similarities between Li-O 2 and Na-O 2 battery systems, in terms of thermodynamics and a structural viewpoint, will be meaningful to promote the development of advanced metal-oxygen batteries. State-of-the-art battery design principles for high-energy-density lithium-oxygen and sodium-oxygen batteries are thus reviewed in depth here. Major drawbacks, reaction mechanisms, and recent strategies to improve performance are also summarized. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Tissue oxygenation in brain, muscle, and fat in a rat model of sleep apnea: differential effect of obstructive apneas and intermittent hypoxia.

Science.gov (United States)

Almendros, Isaac; Farré, Ramon; Planas, Anna M; Torres, Marta; Bonsignore, Maria R; Navajas, Daniel; Montserrat, Josep M

2011-08-01

To test the hypotheses that the dynamic changes in brain oxygen partial pressure (PtO(2)) in response to obstructive apneas or to intermittent hypoxia differ from those in other organs and that the changes in brain PtO(2) in response to obstructive apneas is a source of oxidative stress. Prospective controlled animal study. University laboratory. 98 Sprague-Dawley rats. Cerebral cortex, skeletal muscle, or visceral fat tissues were exposed in anesthetized animals subjected to either obstructive apneas or intermittent hypoxia (apneic and hypoxic events of 15 s each and 60 events/h) for 1 h. Arterial oxygen saturation (SpO(2)) presented a stable pattern, with similar desaturations during both stimuli. The PtO(2) was measured by a microelectrode. During obstructive apneas, a fast increase in cerebral PtO(2) was observed (38.2 ± 3.4 vs. 54.8 ± 5.9 mm Hg) but not in the rest of tissues. This particular cerebral response was not found during intermittent hypoxia. The cerebral content of reduced glutathione was decreased after obstructive apneas (46.2% ± 15.2%) compared to controls (100.0% ± 14.7%), but not after intermittent hypoxia. This antioxidant consumption after obstructive apneas was accompanied by increased cerebral lipid peroxidation under this condition. No changes were observed for these markers in the other tissues. These results suggest that cerebral cortex could be protected in some way from hypoxic periods caused by obstructive apneas. The increased cerebral PtO(2) during obstructive apneas may, however, cause harmful effects (oxidative stress). The obstructive apnea model appears to be more adequate than the intermittent hypoxia model for studying brain changes associated with OSA.

[Domiciliary oxygen therapy].

Science.gov (United States)

Abdel Kafi, S

2010-09-01

In Belgium, oxygen therapy is becoming more and more accessible. When oxygen is needed for short periods or for special indications as palliative care, an agreement between mutual insurance companies and pharmacists allows the practitioner the home installation of gazeous oxygen cylinder or of oxygen concentrator. When long term oxygen therapy (LTOT) is indicated for patients with respiratory insufficiency, the pneumologist must first ask the INAMI the authorization to install one of the following modalities: oxygen concentrator with or without demand oxygen delivery cylinder and liquid oxygen. The goal of LTOT is to increase survival and quality of life. The principal and well accepted indication for LTOT is severe hypoxemia. The beneficial effects of oxygen therapy limited at night or on exertion are controversial. In order to increase patient's autonomy, oxygen can be prescribed for ambulation, respecting prescription's rules. At each step of oxygen therapy implementing (indication, choice of the device and follow-up) the patient under oxygen may benefit from a joint approach between the general practitioner and the chest specialist.

Tools for the development of a benthic quality index for Italian lakes

Directory of Open Access Journals (Sweden)

Angelo SOLIMINI

2006-02-01

Full Text Available In this paper, we propose a methodology to develop a benthic quality index useful for Italian lakes. The existing data about benthic macroinvertebrates of the Italian lakes were collected over a period of 50 years, but only a few lakes such as the Maggiore and the Mergozzo have been intensely studied. Some large lakes such as Lake Como are still almost uninvestigated. In total, 570 benthic macroinvertebrate taxa were identified; of which 373 belong to Chironomidae and 85 to Oligochaeta. With the aim of relating environmental variables with macrobenthos assemblages, we carried out a canonical correlation analysis (CANON using a database that included 1060 sampling points. Both environmental (13 variables describing morphometry and hydrochemistry and biological data (57 taxa were available, but only taxa present in at least 10 samples were selected for data analysis. Three canonical variates were ecologically significant. The first one was correlated with conductivity, pH and alkalinity and accounted for 20% of the total variation. The second one was positively correlated with total phosphorus and N-NH4, and inversely with dissolved oxygen, and accounted for 18% of the total variation. The third one showed a direct correlation with maximum lake depth and volume and an inverse correlation with water temperature, and accounted for 17% of the total variation. A Trophic Status Index (TSI, based on the table 11 of the Italian Law 152/99 (without including chlorophyll, was calculated by ranking percent oxygen saturation, transparency and total phosphorus. TSI was used to test a Benthic Quality Index for Italian Lakes (BQIL which is proposed in the present paper. The algorithm considered three steps. First, the means of three variables were calculated: percent oxygen saturation, transparency and total phosphorus weighted by the taxa abundances. These values are interpreted as optimum for each taxon and used to assign an indicator weight (BQIW. Second

Systematic review of near-infrared spectroscopy determined cerebral oxygenation during non-cardiac surgery

DEFF Research Database (Denmark)

Nielsen, Henning B

2014-01-01

and number of patients included were recorded. There was included 113 articles and evidence suggests that rScO2 is reduced during thoracic surgery involving single lung ventilation, major abdominal surgery, hip surgery, and laparoscopic surgery with the patient placed in anti-Tredelenburg's position....... Shoulder arthroscopy in the beach chair and carotid endarterectomy with clamped internal carotid artery (ICA) also cause pronounced cerebral desaturation. A >20% reduction in rScO2 coincides with indices of regional and global cerebral ischemia during carotid endarterectomy. Following thoracic surgery...

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 ...

Instrumented impact properties of zircaloy-oxygen and zircaloy-hydrogen alloys

Energy Technology Data Exchange (ETDEWEB)

Garde, A.M.; Kassner, T.F.

1980-04-01

Instrumented-impact tests were performed on subsize Charpy speciments of Zircaloy-2 and -4 with up to approx. 1.3 wt % oxygen and approx. 2500 wt ppM hydrogen at temperatures between 373 and 823/sup 0/K. Self-consistent criteria for the ductile-to-brittle transition, based upon a total absorbed energy of approx. 1.3 x 10/sup 4/ J/m/sup 2/, a dynamic fracture toughness of approx. 10 MPa.m/sup 1/2/, and a ductility index of approx. 0, were established relative to the temperature and oxygen concentration of the transformed BETA-phase material. The effect of hydrogen concentration and hydride morphology, produced by cooling Zircaloy-2 specimens through the temperature range of the BETA ..-->.. ..cap alpha..' = hydride phase transformation at approx. 0.3 and 3 K/s, on the impact properties was determined at temperatures between 373 and 673 K. On an atom fraction basis, oxygen has a greater effect than hydrogen on the impact properties of Zircaloy at temperatures between approx. 400 and 600 K. 34 figures.

Effects of levosimendan on glomerular filtration rate, renal blood flow, and renal oxygenation after cardiac surgery with cardiopulmonary bypass: a randomized placebo-controlled study.

Science.gov (United States)

Bragadottir, Gudrun; Redfors, Bengt; Ricksten, Sven-Erik

2013-10-01

Acute kidney injury develops in a large proportion of patients after cardiac surgery because of the low cardiac output syndrome. The inodilator levosimendan increases cardiac output after cardiac surgery with cardiopulmonary bypass, but a detailed analysis of its effects on renal perfusion, glomerular filtration, and renal oxygenation in this group of patients is lacking. We therefore evaluated the effects of levosimendan on renal blood flow, glomerular filtration rate, renal oxygen consumption, and renal oxygen demand/supply relationship, i.e., renal oxygen extraction, early after cardiac surgery with cardiopulmonary bypass. Prospective, placebo-controlled, and randomized trial. Cardiothoracic ICU of a tertiary center. Postcardiac surgery patients (n=30). The patients were randomized to receive levosimendan, 0.1 µg/kg/min after a loading dose of 12 µg/kg (n=15), or placebo (n=15). The experimental procedure started 4-6 hours after surgery in the ICU during propofol sedation and mechanical ventilation. Systemic hemodynamic were evaluated by a pulmonary artery thermodilution catheter. Renal blood flow and glomerular filtration rate were measured by the renal vein retrograde thermodilution technique and by renal extraction of Cr-EDTA, respectively. Central venous pressure was kept constant by colloid/crystalloid infusion. Compared to placebo, levosimendan increased cardiac index (22%), stroke volume index (15%), and heart rate (7%) and decreased systemic vascular resistance index (21%), whereas mean arterial pressure was not affected. Levosimendan induced significant increases in renal blood flow (12%, prenal vascular resistance (18%, prenal oxygen consumption, or renal oxygen extraction, compared to placebo. After cardiac surgery with cardiopulmonary bypass, levosimendan induces a vasodilation, preferentially of preglomerular resistance vessels, increasing both renal blood flow and glomerular filtration rate without jeopardizing renal oxygenation. Due to its

Effect of rehabilitation training combined with hyperbaric oxygen therapy on the nerve cytokine secretion and oxidative stress in rehabilitation period of patients with cerebral infarction

Directory of Open Access Journals (Sweden)

Ling Kong

2017-11-01

Full Text Available Objective: To discuss the influence of rehabilitation training combined with hyperbaric oxygen therapy on the nerve cytokine secretion and oxidative stress in rehabilitation period of patients with cerebral infarction. Methods: A total of 110 patients with cerebral infarction who received rehabilitation therapy in the hospital between January 2015 and May 2017 were divided into routine group (n=55 and hyperbaric oxygen group (n=55 according to random number table. Routine group received regular rehabilitation training, and hyperbaric oxygen group underwent rehabilitation training combined with hyperbaric oxygen therapy. The differences in the serum contents of nerve factors, neurotransmitters and oxidative stress indexes were compared between the two groups at immediately after admission (T0 and after 14 d of treatment (T1. Results: At T0, there was no statistically significant difference in the serum contents of nerve factors, neurotransmitters and oxidative stress indexes between the two groups. At T1, serum nerve factors MBP and NSE contents of hyperbaric oxygen group were lower than those of routine group while NGF content was higher than that of routine group; serum neurotransmitter Glu content was lower than that of routine group while GABA content was higher than that of routine group; serum oxidative stress indexes ROS and LHP contents were lower than those of routine group while CAT and SOD contents were higher than those of routine group. Conclusion: Rehabilitation training combined with hyperbaric oxygen therapy can effectively optimize the nerve function and inhibit the systemic oxidative stress response in rehabilitation period of patients with cerebral infarction.

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

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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.

Oxygen diffusion and oxygen effect in tumor tissue

International Nuclear Information System (INIS)

Eissa, H.M.; Hehn, G.

1979-06-01

The diffusion of oxygen in tumor cords of bronchus carcinoma of the lung have been studied with refined computer methods for solving the diffusion equation in axis symmetric tumor structures. In this tumor configuration we may find three different regions consisting of euoxic cells, hypoxic tumor cells and necrotic parts. In the case of oxygen supply from a capillary inside a cylinder of tumor tissue with radius 200 μm or in a tumor cord of radius 300 μm with oxygen supply by capillaries outside, we get a relation of well oxygenated cells to hypoxic cells approximately as 1:8 or as 1:1.1 respectively. Of course most of the tumor cords observed in histological slices have smaller diameters, so that an average of approximately 20% hypoxic cells can be assumed. Based on the work of Ardenne, the diffusion of oxygen and glucose in a tumor of type DS-carcinosarcom has been investigated in both intact tumor and tumor treated with ionizing radiation. We can show that a strong reoxygenation effect takes place in that the well supplied regions may increase in some tumor configurations up to a factor of four by volume. The biological consequences of the oxygen pressure determined in tumor cells are discussed in detail. The investigation of oxygen diffusion in the intercapillary tumor region should give a quantitative physical basis for considering the oxygen effect with the aim to explain the advantages of neutron therapy against conventional radiotherapy. (orig./MG) [de

Sleep Apnea and Obstructive Airway Disease in Older Men: Outcomes of Sleep Disorders in Older Men Study.

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Zhao, Ying Y; Blackwell, Terri; Ensrud, Kristine E; Stone, Katie L; Omachi, Theodore A; Redline, Susan

2016-07-01

To evaluate the association between obstructive airway disease (OAD) and sleep apnea in older men. A community-based cross-sectional study of 853 community-dwelling older men (mean age 80.7 ± 4.1 years [range 73 to 90]) across 6 centers in the United States from the Outcomes of Sleep Disorders in Older Men Study. Sleep was objectively measured using full in-home polysomnography and lung function was objectively measured using spirometry. The association of OAD (pre-bronchodilator FEV1/FVC ratio sleep apnea (apnea-hypopnea index [AHI] ≥ 15 events/hour) was assessed using logistic regression. OAD and sleep apnea were identified in 111 (13.0%) and 247 (29.0%) men, respectively. In univariate analysis, participants with OAD had a lower AHI (mean ± SD; 8.7 ± 11.7 vs. 12.7 ± 13.8, P = 0.0009) and a lower prevalence of sleep apnea (14.4 vs. 31.1%, P = 0.0003) compared to participants without OAD. OAD remained independently associated with a lower odds of sleep apnea (odds ratio 0.30, 95% CI 0.16 to 0.55, P = 0.0001) after adjustment for demographics, body composition, smoking, and potential mediators (arousal index, time spent in rapid eye movement sleep). Individuals with OAD and sleep apnea (n = 16) had an increased arousal index and lower oxygen saturation level as compared to individuals with OAD alone (P values sleep apnea in a cohort of community-dwelling elderly men, and unexplained by differences in adiposity or sleep architecture. Although uncommon in this cohort, coexisting sleep apnea and OAD was associated with increased sleep fragmentation and nocturnal oxygen desaturation compared to OAD alone. © 2016 Associated Professional Sleep Societies, LLC.

'Multi-associations': predisposed to misinterpretation of peripheral tissue oxygenation and circulation in neonates

International Nuclear Information System (INIS)

Pichler, Gerhard; Pocivalnik, Mirjam; Pichler-Stachl, Elisabeth; Morris, Nicholas; Zotter, Heinz; Müller, Wilhelm; Urlesberger, Berndt; Riedl, Regina

2011-01-01

Interpretation of peripheral circulation in ill neonates is crucial but difficult. The aim was to analyse parameters potentially influencing peripheral oxygenation and circulation. In a prospective observational cohort study in 116 cardio-circulatory stable neonates, peripheral muscle near-infrared spectroscopy (NIRS) with venous occlusion was performed. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO 2 ), fractional oxygen extraction (FOE), fractional tissue oxygen extraction (FTOE), haemoglobin flow (Hbflow), oxygen delivery (DO 2 ), oxygen consumption (VO 2 ), and vascular resistance (VR) were assessed. Correlation coefficients between NIRS parameters and demographic parameters (gestational age, birth weight, age, actual weight, diameter of calf, subcutaneous adipose tissue), monitoring parameters (heart rate, arterial oxygen saturation (SaO 2 ), mean blood pressure (MAP), core/peripheral temperature, central/peripheral capillary refill time) and laboratory parameters (haemoglobin concentration (Hb-blood), pCO 2 ) were calculated. All demographic parameters except for Hbflow and DO 2 correlated with NIRS parameters. Heart rate correlated with TOI, SvO 2 , VO 2 and VR. SaO 2 correlated with FOE/FTOE. MAP correlated with Hbflow, DO 2 , VO 2 and VR. Core temperature correlated with FTOE. Peripheral temperature correlated with all NIRS parameters except VO 2 . Hb-blood correlated with FOE and VR. pCO 2 levels correlated with TOI and SvO 2 . The presence of multiple interdependent factors associated with peripheral oxygenation and circulation highlights the difficulty in interpreting NIRS data. Nevertheless, these findings have to be taken into account when analysing peripheral oxygenation and circulation data

The lung in paracoccidioidomycosis: new insights into old problems

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Andre Nathan Costa

2013-04-01

Full Text Available OBJECTIVES: Chronic paracoccidioidomycosis can diffusely affect the lungs. Even after antifungal therapy, patients may present with residual respiratory abnormalities due to fungus-induced lung fibrosis. METHODS: A cross-sectional analysis of 50 consecutive inactive, chronic paracoccidioidomycosis patients was performed using high resolution computed tomography, pulmonary function tests, ergospirometry, the six-minute walk test and health-related quality of life questionnaires. RESULTS: Radiological abnormalities were present in 98% of cases, the most frequent of which were architectural distortion (90%, reticulate and septal thickening (88%, centrilobular and paraseptal emphysema (84% and parenchymal bands (74%. Patients typically presented with a mild obstructive disorder and a mild reduction in diffusion capacity with preserved exercise capacity, including VO2max and six-minute walking distance. Patient evaluation with the Saint-George Respiratory Questionnaire showed low impairment in the health-related quality of life, and the Medical Research Council questionnaire indicated a low dyspnea index. There were, however, patients with significant oxygen desaturation upon exercise that was associated with respiratory distress compared with the non-desaturated patients. The initial counterimmunoelectrophoresis of these patients was higher and lung emphysema was more prominent; however, there were no differences in the interstitial fibrotic tomographic abnormalities, tobacco exposure, functional responses, exercise capacity or quality of life. CONCLUSIONS: Inactive, chronic paracoccidioidomycosis patients show persistent and disseminated radiological abnormalities by high resolution computed tomography, short impairments in pulmonary function and low impacts on aerobic capacity and quality of life. However, there was a subset of individuals whose functional impairment was more severe. These patients present with higher initial serology and more

Relationship between Clinical and Polysomnography Measures Corrected for CPAP Use.

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Kirkham, Erin M; Heckbert, Susan R; Weaver, Edward M

2015-11-15

The changes in patient-reported measures of obstructive sleep apnea (OSA) burden are largely discordant with the change in apnea-hypopnea index (AHI) and other polysomnography measures before and after treatment. For patients treated with continuous positive airway pressure (CPAP), some investigators have theorized that this discordance is due in part to the variability in CPAP use. We aim to test the hypothesis that patient-reported outcomes of CPAP treatment have stronger correlations with AHI when it is corrected for mean nightly CPAP use. This was a cross-sectional study of 459 adults treated with CPAP for OSA. Five patient-reported measures of OSA burden were collected at baseline and after 6 months of CPAP therapy. The correlations between the change in each patient-reported measure and the change in AHI as well as mean nightly AHI (corrected for CPAP use with a weighted average formula) were measured after 6 months of treatment. The same analysis was repeated for 4 additional polysomnography measures, including apnea index, arousal index, lowest oxyhemoglobin saturation, and desaturation index. The change in AHI was weakly but significantly correlated with change in 2 of the 5 clinical measures. The change in mean nightly AHI demonstrated statistically significant correlations with 4 out of 5 clinical measures, though each with coefficients less than 0.3. Similar results were seen for apnea index, arousal index, lowest oxyhemoglobin saturation, and desaturation index. Correction for CPAP use yielded overall small but significant improvements in the correlations between patient-reported measures of sleep apnea burden and polysomnography measures after 6 months of treatment. © 2015 American Academy of Sleep Medicine.

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.

Survey of water quality in Moradbeik river basis on WQI index by GIS

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Mohammad Taghi Samadi

2015-01-01

Full Text Available Background: Survey of pollution and evaluation of water quality in rivers with Oregon Water Quality Index (OWQI and GIS are effective tools for management of the impact of environmental water resources. The information in calculating the WQI of Moradbeikriver allowed us to take our tests results and make a scientific conclusion about the quality of water. GIS can be a powerful tool for developing solutions for water resources problems for assessing water quality, determining water availability, preventing flooding, understanding the natural environment, and managing water resources on a local or regional scale. Methods: The WQI of Moradbeikriver consists of nine tests: Fecal Coliform (FC, Biochemical Oxygen Demand (BOD5, Nitrates (NO3, Total Phosphate (PO4, pH, temperature, Dissolved Oxygen (DO, turbidity, and Total Solid (TS. Water quality of Moradbeikriver was investigated for 12 months. Concentrations of these nine variables were normalized on a scale from 0 to 100 and translated into statements of water quality (excellent, good, regular, fair, and poor. Also this data were analyzed with WQI index, and then river basis on water quality was zoning by GIS. Results: The average of WQI was 61.62, which corresponded to ‘‘medium’’ quality water at the sampling point 1 (best station and decreased to around 26.41 (bad quality at sampling point 6. The association between sampling points and water quality indexes was statistically significant (P<0.05. Conclusion: Based on physical, chemical and biological agent monitoring and also with control of water quality indexes of these points, we observed wastewater and other river pollutants.

Post-operative recovery profile after laparoscopic cholecystectomy: a prospective, observational study of a multimodal anaesthetic regime

DEFF Research Database (Denmark)

Jensen, K; Kehlet, H; Lund, Claus Michael

2007-01-01

BACKGROUND: Laparoscopic cholecystectomy is now often an ambulatory procedure, but dependent on short-term post-operative complaints of pain and post-operative nausea and vomiting (PONV). The efficacy of post-anaesthesia care units (PACUs) is therefore important to facilitate return to normal fun...... are predictors of a complicated recovery profile and deserve further attention. Transient oxygen desaturations postpone discharge from the PACU, but the clinical significance of this fact is questionable. Udgivelsesdato: 2007-Apr...

Intermittent hypoxia from obstructive sleep apnea may cause neuronal impairment and dysfunction in central nervous system: the potential roles played by microglia

OpenAIRE

Yang, Qingchan; Wang, Yan; Feng, Jing; Cao, Jie; Chen, Baoyuan

2013-01-01

Qingchan Yang,1,* Yan Wang,2,* Jing Feng,2 Jie Cao,2 Baoyuan Chen2 1Graduate School of Tianjin Medical University, 2Respiratory Department, Tianjin Medical University General Hospital, Tianjin, People's Republic of China *These authors contributed equally to this work Abstract: Obstructive sleep apnea (OSA) is a common condition characterized by repetitive episodes of complete (apnea) or partial (hypopnea) obstruction of the upper airway during sleep, resulting in oxygen desaturation...

Rieske non-heme iron-dependent oxygenases catalyse diverse reactions in natural product biosynthesis.

Science.gov (United States)

Perry, Christopher; de Los Santos, Emmanuel L C; Alkhalaf, Lona M; Challis, Gregory L

2018-04-13

Covering: up to the end of 2017The roles played by Rieske non-heme iron-dependent oxygenases in natural product biosynthesis are reviewed, with particular focus on experimentally characterised examples. Enzymes belonging to this class are known to catalyse a range of transformations, including oxidative carbocyclisation, N-oxygenation, C-hydroxylation and C-C desaturation. Examples of such enzymes that have yet to be experimentally investigated are also briefly described and their likely functions are discussed.

Oxygen effect and intracellular oxygen content (adaptation hypothesis)

Energy Technology Data Exchange (ETDEWEB)

Yarmonenko, S P; Ehpshtejn, I M [Akademiya Meditsinskikh Nauk SSSR, Moscow. Onkologicheskij Tsentr

1977-01-01

Experimental data indicating that a radiomodifying action of hypoxia is dependent on the ''prehistory'' of the irradiated object are considered. This dependence manifests itself in a decreased protective action of acute hypoxia on the hypoxia-adapted objects. To explain this a hypothesis is proposed connecting a degree of cell radiosensitivity modification, determined by the oxygen effect, with the intracellular oxygen content. The latter, in accord with current ideas, is regulated by variations in the diffusion resistance to oxygen shown by the cytoplasmic membranes depending on the energy level of the cell and the degree of its oxygenation.

Oxygen effect and intracellular oxygen content (adaptation hypothesis)

International Nuclear Information System (INIS)

Yarmonenko, S.P.; Ehpshtejn, I.M.

1977-01-01

Experimental data indicating that a radiomodifying action of hypoxia is dependent on the ''prehistory'' of the irradiated object are considered. This dependence manifests itself in a decreased protective action of acute hypoxia on the hypoxia-adapted objects. To explain this a hypothesis is proposed connecting a degree of cell radiosensitivity modification, determined by the oxygen effect, with the intracellular oxygen content. The latter, in accord with current ideas, is regulated by variations in the diffusion resistance to oxygen shown by the cytoplasmic membranes depending on the energy level of the cell and the degree of its oxygenation

INDEXING AND INDEX FUNDS

Directory of Open Access Journals (Sweden)

HAKAN SARITAŞ

2013-06-01

Full Text Available Proponents of the efficient market hypothesis believe that active portfolio management is largely wasted effort and unlikely to justify the expenses incurred. Therefore, they advocate a passive investment strategy that makes no attempt to outsmart the market. One common strategy for passive management is indexing where a fund is designed to replicate the performance of a broad-based index of stocks and bonds. Traditionally, indexing was used by institutional investors, but today, the use of index funds proliferated among individual investors. Over the years, both international and domestic index funds have disproportionately outperformed the market more than the actively managed funds have.

Step Test: a method for evaluating maximum oxygen consumption to determine the ability kind of work among students of medical emergencies.

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Heydari, Payam; Varmazyar, Sakineh; Nikpey, Ahmad; Variani, Ali Safari; Jafarvand, Mojtaba

2017-03-01

Maximum oxygen consumption shows the maximum oxygen rate of muscle oxygenation that is acceptable in many cases, to measure the fitness between person and the desired job. Given that medical emergencies are important, and difficult jobs in emergency situations require people with high physical ability and readiness for the job, the aim of this study was to evaluate the maximum oxygen consumption, to determine the ability of work type among students of medical emergencies in Qazvin in 2016. This study was a descriptive - analytical, and in cross-sectional type conducted among 36 volunteer students of medical emergencies in Qazvin in 2016. After necessary coordination for the implementation of the study, participants completed health questionnaires and demographic characteristics and then the participants were evaluated with step tests of American College of Sport Medicine (ACSM). Data analysis was done by SPSS version 18 and U-Mann-Whitney tests, Kruskal-Wallis and Pearson correlation coefficient. Average of maximum oxygen consumption of the participants was estimated 3.15±0.50 liters per minute. 91.7% of medical emergencies students were selected as appropriate in terms of maximum oxygen consumption and thus had the ability to do heavy and too heavy work. Average of maximum oxygen consumption evaluated by the U-Mann-Whitney test and Kruskal-Wallis, had significant relationship with age (p<0.05) and weight groups (p<0.001). There was a significant positive correlation between maximum oxygen consumption with weight and body mass index (p<0.001). The results of this study showed that demographic variables of weight and body mass index are the factors influencing the determination of maximum oxygen consumption, as most of the students had the ability to do heavy, and too heavy work. Therefore, people with ability to do average work are not suitable for medical emergency tasks.

Biceps brachii muscle oxygenation in electrical muscle stimulation.

Science.gov (United States)

Muthalib, Makii; Jubeau, Marc; Millet, Guillaume Y; Maffiuletti, Nicola A; Ferrari, Marco; Nosaka, Kazunori

2010-09-01

The purpose of this study was to compare between electrical muscle stimulation (EMS) and maximal voluntary (VOL) isometric contractions of the elbow flexors for changes in biceps brachii muscle oxygenation (tissue oxygenation index, TOI) and haemodynamics (total haemoglobin volume, tHb = oxygenated-Hb + deoxygenated-Hb) determined by near-infrared spectroscopy (NIRS). The biceps brachii muscle of 10 healthy men (23-39 years) was electrically stimulated at high frequency (75 Hz) via surface electrodes to evoke 50 intermittent (4-s contraction, 15-s relaxation) isometric contractions at maximum tolerated current level (EMS session). The contralateral arm performed 50 intermittent (4-s contraction, 15-s relaxation) maximal voluntary isometric contractions (VOL session) in a counterbalanced order separated by 2-3 weeks. Results indicated that although the torque produced during EMS was approximately 50% of VOL (P<0.05), there was no significant difference in the changes in TOI amplitude or TOI slope between EMS and VOL over the 50 contractions. However, the TOI amplitude divided by peak torque was approximately 50% lower for EMS than VOL (P<0.05), which indicates EMS was less efficient than VOL. This seems likely because of the difference in the muscles involved in the force production between conditions. Mean decrease in tHb amplitude during the contraction phases was significantly (P<0.05) greater for EMS than VOL from the 10th contraction onwards, suggesting that the muscle blood volume was lower in EMS than VOL. It is concluded that local oxygen demand of the biceps brachii sampled by NIRS is similar between VOL and EMS.

Theory and development of fluorescence-based optochemical oxygen sensors: oxygen optodes.

Science.gov (United States)

Opitz, N; Lübbers, D W

1987-01-01

As the preceding considerations concerning the physical and technical features of oxygen optodes have demonstrated, fluorescence-based optochemical oxygen sensors possess certain advantages and peculiarities compared to conventionally applied electrochemical sensors such as polarographic oxygen electrodes. First, in contrast to oxygen electrodes, oxygen measurements with oxygen optodes do not suffer from distortions caused by the reference electrodes. In addition, because of the polarographic process, platinum electrodes continuously consume oxygen, which falsifies the results, especially when small sample volumes or long-term measurements, or both, are involved, whereas the sensor layer of oxygen optodes must only be equilibrated. Moreover, the surface of the platinum wire has to be catalytically clean in order to obtain a plateau of the polarogram and, consequently, to achieve a low rest current at zero PO2. Unfortunately, the demand for catalytically clean platinum surfaces turns out to be rather critical, since surface contamination occurs even with membranized electrodes, resulting in the well-known phenomenon of "electrode poisoning." The question of the specificity of oxygen electrodes also must be considered. In this context, CO2 and halothane may interfere with oxygen measurements, whereas fluorescence quenching is unaffected by CO2 and halothane affects the measurements only slightly, depending on the special indicator used. Furthermore, because of the flow dependence, oxygen measurements with the oxygen electrode show a distinct "stirring effect" caused by the turbulence in front of the electrode, which disturbs the diffusion field. Because of the completely different physical principle of fluorescence optical sensors, such influences are not observed with oxygen optodes. In addition, isolation and shielding of electrical circuits found in electrodes are not necessary for optodes. Furthermore, the sensitivity of oxygen optodes can be tuned to the desired

Oxygen Therapy

Science.gov (United States)

... their breathing to dangerously low levels. Will I need oxygen when I sleep? Usually if you use supplemental oxygen during the ... your health care provider tells you you only need to use oxygen for exercise or sleep. Even if you feel “fine” off of your ...

The oxygen-conserving potential of the diving response: A kinetic-based analysis.

Science.gov (United States)

Costalat, Guillaume; Coquart, Jeremy; Castres, Ingrid; Joulia, Fabrice; Sirost, Olivier; Clua, Eric; Lemaître, Frédéric

2017-04-01

We investigated the oxygen-conserving potential of the human diving response by comparing trained breath-hold divers (BHDs) to non-divers (NDs) during simulated dynamic breath-holding (BH). Changes in haemodynamics [heart rate (HR), stroke volume (SV), cardiac output (CO)] and peripheral muscle oxygenation [oxyhaemoglobin ([HbO 2 ]), deoxyhaemoglobin ([HHb]), total haemoglobin ([tHb]), tissue saturation index (TSI)] and peripheral oxygen saturation (SpO 2 ) were continuously recorded during simulated dynamic BH. BHDs showed a breaking point in HR kinetics at mid-BH immediately preceding a more pronounced drop in HR (-0.86 bpm.% -1 ) while HR kinetics in NDs steadily decreased throughout BH (-0.47 bpm.% -1 ). By contrast, SV remained unchanged during BH in both groups (all P > 0.05). Near-infrared spectroscopy (NIRS) results (mean ± SD) expressed as percentage changes from the initial values showed a lower [HHb] increase for BHDs than for NDs at the cessation of BH (+24.0 ± 10.1 vs. +39.2 ± 9.6%, respectively; P kinetic-based approach we used provides further credence to the concept of an "oxygen-conserving breaking point" in the human diving response.

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.

Comparison between model-predicted tumor oxygenation dynamics and vascular-/flow-related Doppler indices.

Science.gov (United States)

Belfatto, Antonella; Vidal Urbinati, Ailyn M; Ciardo, Delia; Franchi, Dorella; Cattani, Federica; Lazzari, Roberta; Jereczek-Fossa, Barbara A; Orecchia, Roberto; Baroni, Guido; Cerveri, Pietro

2017-05-01

two presented poor correlations. The latter patients were the ones featuring the smallest tumor reduction throughout the treatment, typical of hypoxic conditions. Moreover, the average oxygenation value predicted by the model was close to the average vascularization-flow index (average difference: 7%). The results suggest that the modeled relation between tumor evolution and oxygen dynamics was reasonable enough to provide realistic oxygenation curves in five cases (correlation greater than 50%) out of seven. In case of nonresponsive tumors, the model failed in predicting the oxygenation trend while succeeded in reproducing the average oxygenation value according to the mean vascularization-flow index. Despite the need for deeper investigations, the outcomes of the present work support the hypothesis that a simple macroscale model of tumor response to radiotherapy is able to predict the tumor oxygenation. The possibility of an objective and quantitative validation on imaging data discloses the possibility to translate them as decision support tools in clinical practice and to move a step forward in the treatment personalization. © 2017 American Association of Physicists in Medicine.

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.

Reactive oxygen species explicit dosimetry (ROSED) of a type 1 photosensitizer

Science.gov (United States)

Ong, Yi Hong; Kim, Michele M.; Huang, Zheng; Zhu, Timothy C.

2018-02-01

Type I photodynamic therapy (PDT) is based on the use of photochemical reactions mediated through an interaction between a tumor-selective photosensitizer, photoexcitation with a specific wavelength of light, and production of reactive oxygen species (ROS). The goal of this study is to develop a model to calculate reactive oxygen species concentration ([ROS]rx) after Tookad®-mediated vascular PDT. Mice with radiation-induced fibrosarcoma (RIF) tumors were treated with different light fluence and fluence rate conditions. Explicit measurements of photosensitizer drug concentration were made via diffuse reflective absorption spectrum using a contact probe before and after PDT. Blood flow and tissue oxygen concentration over time were measured during PDT as a mean to validate the photochemical parameters for the ROSED calculation. Cure index was computed from the rate of tumor regrowth after treatment and was compared against three calculated dose metrics: total light fluence, PDT dose, reacted [ROS]rx. The tumor growth study demonstrates that [ROS]rx serves as a better dosimetric quantity for predicting treatment outcome, as a clinically relevant tumor growth endpoint.

In vitro autoradiographic studies for determination of mitotic index and labelling index in biopsies of the human oral mucosa

International Nuclear Information System (INIS)

Etzbach, T.

1980-01-01

In order to find the most favourable method of incubation for in-vitro autoradiographies of biopsies of human oral mucosa, tissue biopsies were taken from oral mucosa transplants of 10 patients (7 females, 3 males) and either fixed or incubated at once. The author then investigated the mitotic index of the non-incubated tissue specimens, the mitotic index of the tissue specimens incubated in atmospheric conditions (A), and the mitotic index of the tissue specimens incubated under pressure (B). Simultaneously, autoradiographs of the incubated tissue specimens were prepared in order to determine their labelling indices. The mitotic indices of the non-incubated tissue specimen were found to differ significantly from those of the A-incubated tissue specimens. A similar difference was found between the mitotic indices of the A- and B-incubated tissue biopsies. Further, the labelling indices of A autoradiographs differed significantly from the labelling indices of B autoradiographs. The findings suggest that incubation with an excess oxygen pressure of 2 bar is the method of choice for in-vitro studies of human oral mucosa as the cells retain their specific activity and cell processes will continue unhindered. Further, the findings can be transferred to in-vivo conditions with a reasonable error rate. (orig./MG) [de

Calculations of oxide formation on low-index Cu surfaces

Energy Technology Data Exchange (ETDEWEB)

Lian, Xin; Liu, Renlong, E-mail: lrl@cqu.edu.cn, E-mail: henkelman@utexas.edu [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030 (China); Xiao, Penghao; Yang, Sheng-Che; Henkelman, Graeme, E-mail: lrl@cqu.edu.cn, E-mail: henkelman@utexas.edu [Department of Chemistry and the Institute for Computational and Engineering Sciences, University of Texas at Austin, Austin, Texas 78712-0165 (United States)

2016-07-28

Density-functional theory is used to evaluate the mechanism of copper surface oxidation. Reaction pathways of O{sub 2} dissociation on the surface and oxidation of the sub-surface are found on the Cu(100), Cu(110), and Cu(111) facets. At low oxygen coverage, all three surfaces dissociate O{sub 2} spontaneously. As oxygen accumulates on the surfaces, O{sub 2} dissociation becomes more difficult. A bottleneck to further oxidation occurs when the surfaces are saturated with oxygen. The barriers for O{sub 2} dissociation on the O-saturated Cu(100)-c(2×2)-0.5 monolayer (ML) and Cu(100) missing-row structures are 0.97 eV and 0.75 eV, respectively; significantly lower than those have been reported previously. Oxidation of Cu(110)-c(6×2), the most stable (110) surface oxide, has a barrier of 0.72 eV. As the reconstructions grow from step edges, clean Cu(110) surfaces can dissociatively adsorb oxygen until the surface Cu atoms are saturated. After slight rearrangements, these surface areas form a “1 ML” oxide structure which has not been reported in the literature. The barrier for further oxidation of this “1 ML” phase is only 0.31 eV. Finally the oxidized Cu(111) surface has a relatively low reaction energy barrier for O{sub 2} dissociation, even at high oxygen coverage, and allows for facile oxidation of the subsurface by fast O diffusion through the surface oxide. The kinetic mechanisms found provide a qualitative explanation of the observed oxidation of the low-index Cu surfaces.

Endothelin-1 levels in the pathophysiology of chronic obstructive pulmonary disease and bronchial asthma.

Science.gov (United States)

Spiropoulos, K; Trakada, G; Nikolaou, E; Prodromakis, E; Efremidis, G; Pouli, A; Koniavitou, A

2003-08-01

Endothelin-1 (ET-1) has been implicated in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). The ET-1 levels are elevated during exacerbations of asthma and COPD in bronchoalveolar lavage, serum, and sputum and fails with treatment of the exacerbations. Hypoxemia stimulates ET-1 secretion. The aim of this study was to examine the serum ET-1 levels in stable asthmatic and COPD patients. We examined 48 COPD and 26 asthmatic patients and 34 normal subjects. We collected arterial samples to measure baseline ET-1 levels in all patients and in the control group, during the day. All the patients underwent formal polysomnography (EEG, ECG, airflow, respiratory muscle movement, oximeter) to detect the presence of nocturnal, nonapneic, and oxyhemoglobin desaturation. Twelve of the COPD patients and six of the asthmatic patients were disqualified because of inadequate sleep or sleep apnea syndrome. Nineteen of the COPD patients desaturated below a baseline sleep saturation of 90% for 5 min or more, reaching a nadir saturation of at least 85%. We collected arterial samples to measure ET-1 levels, 5 min after the first period of desaturation in each of the 19 desaturators COPD patients. None of the 20 asthmatic patients exhibited oxyhemoglobin desaturation during sleep. Baseline arterial ET-1 levels during the day were significantly higher in "desaturators" COPD patients (2.08+/-0.28 pg/ml) compared to "non-desaturators" COPD patients (1.38+/-0.16 pg/ml) (P<0.001) and to asthmatics (0.7+/-0.85 pg/ml) (P<0.001). ET-1 Levels in normal subjects were 1.221+/-0.02 pg/ml. In "desaturators" COPD patients ET-1 levels during the night, 5 min after the first oxyhemoglobin desaturation, were significantly higher (4.28+/-1.10 pg/ml) compared to those during the day (2.08+/-0.28 pg/ml) (P<0.001). A significant negative correlation was observed between ET-1 levels and degree of desaturation during the day (P=0.005, r=0.632) and during the night (P<0.001, r=0

11-Oxygenated C19 Steroids Are the Predominant Androgens in Polycystic Ovary Syndrome.

Science.gov (United States)

O'Reilly, Michael W; Kempegowda, Punith; Jenkinson, Carl; Taylor, Angela E; Quanson, Jonathan L; Storbeck, Karl-Heinz; Arlt, Wiebke

2017-03-01

Androgen excess is a defining feature of polycystic ovary syndrome (PCOS), but the exact origin of hyperandrogenemia remains a matter of debate. Recent studies have highlighted the importance of the 11-oxygenated C19 steroid pathway to androgen metabolism in humans. In this study, we analyzed the contribution of 11-oxygenated androgens to androgen excess in women with PCOS. One hundred fourteen women with PCOS and 49 healthy control subjects underwent measurement of serum androgens by liquid chromatography-tandem mass spectrometry. Twenty-four-hour urinary androgen excretion was analyzed by gas chromatography-mass spectrometry. Fasting plasma insulin and glucose were measured for homeostatic model assessment of insulin resistance. Baseline demographic data, including body mass index, were recorded. As expected, serum concentrations of the classic androgens testosterone (P PCOS. Mirroring this, serum 11-oxygenated androgens 11β-hydroxyandrostenedione, 11-ketoandrostenedione, 11β-hydroxytestosterone, and 11-ketotestosterone were significantly higher in PCOS than in control subjects, as was the urinary 11-oxygenated androgen metabolite 11β-hydroxyandrosterone. The proportionate contribution of 11-oxygenated to total serum androgens was significantly higher in patients with PCOS compared with control subjects [53.0% (interquartile range, 48.7 to 60.3) vs 44.0% (interquartile range, 32.9 to 54.9); P PCOS had significantly increased 11-oxygenated androgens. Serum 11β-hydroxyandrostenedione and 11-ketoandrostenedione correlated significantly with markers of insulin resistance. We show that 11-oxygenated androgens represent the majority of circulating androgens in women with PCOS, with close correlation to markers of metabolic risk.

Water quality index and eutrophication indices of Caiabi River, MT

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Grasiane Andrietti

2016-03-01

Full Text Available The objective of this study was to evaluate the water quality of the Caiabi River based upon the water quality index (WQI and the trophic state index (TSI, considering seasonal and spatial variations, with the aim of determining the most appropriate monitoring design for this study site. Sampling for water quality monitoring was conducted at five points on the Caiabi River from July 2012 to June 2013. Quality parameters quantified were as follows: pH, temperature, conductivity, dissolved oxygen, total and thermotolerant coliforms, turbidity, Kjeldahl nitrogen, nitrite, nitrate, total phosphorus, biochemical oxygen demand, series of solids, and chlorophyll a. Sampling procedures and analysis followed the methods recommended by the Standard Methods for the Examination of Water and Wastewater. The WQI results showed that the quality of the Caiabi River water is good. TSI results demonstrated the low risk of eutrophication in the Caiabi River, indicating an ultra-oligotrophic lotic environment. Analysis of variance showed that 10 of the 16 monitored quality parameters presented differences of means between the dry and rainy seasons or among the monitored points or in the interaction between seasons and points. These results indicate that two annual sampling collections at two points may be sufficient to describe the water quality behavior in the basin, as long as the conditions of land use are stable.

Long-term Effects of Recurrent Intermittent Hypoxia and Hyperoxia on Respiratory System Mechanics in Neonatal Mice

OpenAIRE

Dylag, Andrew M.; Mayer, Catherine A.; Raffay, Thomas M.; Martin, Richard J.; Jafri, Anjum; MacFarlane, Peter M.

2016-01-01

Background Premature infants are at increased risk for wheezing disorders. Clinically, these neonates experience recurrent episodes of apnea and desaturation often treated by increasing the fraction of inspired oxygen (FIO2). We developed a novel paradigm of neonatal intermittent hypoxia with subsequent hyperoxia overshoots (CIHO/E) and hypothesized that CIHO/E elicits long-term changes on pulmonary mechanics in mice. Methods Neonatal C57BL/6 mice received CIHO/E, which consisted of 10% O2 (1...

Methanol Droplet Extinction in Oxygen/Carbon-dioxide/Nitrogen Mixtures in Microgravity: Results from the International Space Station Experiments

Science.gov (United States)

Nayagam, Vedha; Dietrich, Daniel L.; Ferkul, Paul V.; Hicks, Michael C.; Williams, Forman A.

2012-01-01

Motivated by the need to understand the flammability limits of condensed-phase fuels in microgravity, isolated single droplet combustion experiments were carried out in the Combustion Integrated Rack Facility onboard the International Space Station. Experimental observations of methanol droplet combustion and extinction in oxygen/carbon-dioxide/nitrogen mixtures at 0.7 and 1 atmospheric pressure in quiescent microgravity environment are reported for initial droplet diameters varying between 2 mm to 4 mm in this study.The ambient oxygen concentration was systematically lowered from test to test so as to approach the limiting oxygen index (LOI) at fixed ambient pressure. At one atmosphere pressure, ignition and some burning were observed for an oxygen concentration of 13% with the rest being nitrogen. In addition, measured droplet burning rates, flame stand-off ratios, and extinction diameters are presented for varying concentrations of oxygen and diluents. Simplified theoretical models are presented to explain the observed variations in extinction diameter and flame stand-off ratios.

Supplemental Oxygen in Elective Cesarean Section under Spinal Anesthesia: Handle the Sword with Care

Directory of Open Access Journals (Sweden)

Saban Yalcin

2013-09-01

Full Text Available Background and objectives: : We aimed to investigate the effect of 21% and 40% oxygen supplementation on maternal and neonatal oxidative stress in elective cesarean section (CS under spinal anesthesia. Methods: Eighty term parturients undergoing elective CS under spinal anesthesia were enrolled in the study. We allocated patients randomly to breathe 21% (air group or 40% (oxygen group oxygen from the time of skin incision until the end of the operation. We collected maternal pre- and post-operative and umbilical artery (UA blood samples. Total antioxidant capacity (TAC, total oxidant status (TOS and the oxidative stress index (OSI were measured. Results: Age, weight, height, parity, gestation week, spinal-skin incision time, skin incision-delivery time, delivery time, operation time, 1st and 5th minutes Apgar scores, and birth weight were similar between the groups (p > 0.05 for all comparisons. There were no differences in preoperative TAC, TOS, or OSI levels between the groups (p > 0.05 for all comparisons. Postoperative maternal TAC, TOS and OSI levels significantly increased in the oxygen group (p = 0.047, < 0.001 and 0.038, respectively; umbilical artery TAC levels significantly increased in the oxygen group (p = 0.003; and umbilical artery TOS and OSI levels significantly increased in the air group (p = 0.02 and < 0.001, respectively. Conclusions: The difference in impact on maternal and fetal oxidative stress of supplemental 40% compared to 21% oxygen mandates further large-scale studies that investigate the role of oxygen supplementation during elective CS under spinal anesthesia. Keywords: Anesthesia, Spinal, Cesarean Section, Oxidative Stress, Oxygen, Oxygen Inhalation Therapy

Significantly reduced hypoxemic events in morbidly obese patients undergoing gastrointestinal endoscopy: Predictors and practice effect

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Basavana Gouda Goudra

2014-01-01

Full Text Available Background: Providing anesthesia for gastrointestinal (GI endoscopy procedures in morbidly obese patients is a challenge for a variety of reasons. The negative impact of obesity on the respiratory system combined with a need to share the upper airway and necessity to preserve the spontaneous ventilation, together add to difficulties. Materials and Methods: This retrospective cohort study included patients with a body mass index (BMI >40 kg/m 2 that underwent out-patient GI endoscopy between September 2010 and February 2011. Patient data was analyzed for procedure, airway management technique as well as hypoxemic and cardiovascular events. Results: A total of 119 patients met the inclusion criteria. Our innovative airway management technique resulted in a lower rate of intraoperative hypoxemic events compared with any published data available. Frequency of desaturation episodes showed statistically significant relation to previous history of obstructive sleep apnea (OSA. These desaturation episodes were found to be statistically independent of increasing BMI of patients. Conclusion: Pre-operative history of OSA irrespective of associated BMI values can be potentially used as a predictor of intra-procedural desaturation. With suitable modification of anesthesia technique, it is possible to reduce the incidence of adverse respiratory events in morbidly obese patients undergoing GI endoscopy procedures, thereby avoiding the need for endotracheal intubation.

Significantly reduced hypoxemic events in morbidly obese patients undergoing gastrointestinal endoscopy: Predictors and practice effect.

Science.gov (United States)

Goudra, Basavana Gouda; Singh, Preet Mohinder; Penugonda, Lakshmi C; Speck, Rebecca M; Sinha, Ashish C

2014-01-01

Providing anesthesia for gastrointestinal (GI) endoscopy procedures in morbidly obese patients is a challenge for a variety of reasons. The negative impact of obesity on the respiratory system combined with a need to share the upper airway and necessity to preserve the spontaneous ventilation, together add to difficulties. This retrospective cohort study included patients with a body mass index (BMI) >40 kg/m(2) that underwent out-patient GI endoscopy between September 2010 and February 2011. Patient data was analyzed for procedure, airway management technique as well as hypoxemic and cardiovascular events. A total of 119 patients met the inclusion criteria. Our innovative airway management technique resulted in a lower rate of intraoperative hypoxemic events compared with any published data available. Frequency of desaturation episodes showed statistically significant relation to previous history of obstructive sleep apnea (OSA). These desaturation episodes were found to be statistically independent of increasing BMI of patients. Pre-operative history of OSA irrespective of associated BMI values can be potentially used as a predictor of intra-procedural desaturation. With suitable modification of anesthesia technique, it is possible to reduce the incidence of adverse respiratory events in morbidly obese patients undergoing GI endoscopy procedures, thereby avoiding the need for endotracheal intubation.

Wobbe index control system in gas industry processes; Systeme de controle de l'index de Wobbe du gaz naturel dans les processus industriels

Energy Technology Data Exchange (ETDEWEB)

Cassibba, M.; Bertani, M. [SNAM, (Italy)

2000-07-01

Natural gas supplied to industry for process utilizations originates from different sources and that can cause fluctuations in gas composition. Changing gas composition may lead to production problems in industry with sensitive thermal processes (particularly glass industry and thermal metal treatments), such as efficiency and product quality. An equipment suitable to control and adjust such variations has been developed. Experimental tests in laboratory were carried out in order to investigate the control system accuracy and reliability. In particular five different settings were tested: at a preset thermal input by adjusting the natural gas flow rate in respect to Wobbe Index variations; at a set furnace temperature and stack oxygen level with variable thermal input by monitoring the Wobbe Index value; at constant Wobbe Index value by adding air to natural gas; at constant thermal input and prefixed Wobbe Index value by adding air to natural gas and varying the air and gas mixture flow rate; gross calorific value control by adding air or LPG to natural gas. All the tested settings gave good results. This report illustrates these results and the main features of the control system. The control and regulation system was installed in two glass factories for field tests. (authors)

Characterization of water quality and simulation of temperature, nutrients, biochemical oxygen demand, and dissolved oxygen in the Wateree River, South Carolina, 1996-98

Science.gov (United States)

Feaster, Toby D.; Conrads, Paul

2000-01-01

and validate the Branched Lagrangian Transport Model. The data include dye-tracer concentrations collected at six locations, stream-reaeration data collected at four locations, and water-quality and water-temperature data collected at nine locations. Hydraulic data for the Branched Lagrangian Transport Model were simulated by using the U.S. Geological Survey BRANCH one-dimensional, unsteady-flow model. Data that were used to calibrate and validate the BRANCH model included time-series of water-level and streamflow data at three locations. The domain of the hydraulic model and the transport model was a 57.3- and 43.5-mile reach of the river, respectively. A sensitivity analysis of the simulated dissolved-oxygen concentrations to model coefficients and data inputs indicated that the simulated dissolved-oxygen concentrations were most sensitive to changes in the boundary concentration inputs of water temperature and dissolved oxygen followed by sensitivity to the change in streamflow. A 35-percent increase in streamflow resulted in a negative normalized sensitivity index, indicating a decrease in dissolved-oxygen concentrations. The simulated dissolved-oxygen concentrations showed no significant sensitivity to changes in model input rate kinetics. To demonstrate the utility of the Branched Lagrangian Transport Model of the Wateree River, the model was used to simulate several hydrologic and water-quality scenarios to evaluate the effects on simulated dissolved-oxygen concentrations. The first scenario compared the 24-hour mean dissolved-oxygen concentrations for August 13, 1997, as simulated during the model validation, with simulations using two different streamflow patterns. The mean streamflow for August 13, 1997, was 2,000 cubic feet per second. Simulations were run using mean streamflows of 1,000 and 1,400 cubic feet per second while keeping the water-quality boundary conditions the same as were used during the validation simulations. When compared t

Oxygen-Partial-Pressure Sensor for Aircraft Oxygen Mask

Science.gov (United States)

Kelly, Mark; Pettit, Donald

2003-01-01

A device that generates an alarm when the partial pressure of oxygen decreases to less than a preset level has been developed to help prevent hypoxia in a pilot or other crewmember of a military or other high-performance aircraft. Loss of oxygen partial pressure can be caused by poor fit of the mask or failure of a hose or other component of an oxygen distribution system. The deleterious physical and mental effects of hypoxia cause the loss of a military aircraft and crew every few years. The device is installed in the crewmember s oxygen mask and is powered via communication wiring already present in all such oxygen masks. The device (see figure) includes an electrochemical sensor, the output potential of which is proportional to the partial pressure of oxygen. The output of the sensor is amplified and fed to the input of a comparator circuit. A reference potential that corresponds to the amplified sensor output at the alarm oxygen-partial-pressure level is fed to the second input of the comparator. When the sensed partial pressure of oxygen falls below the minimum acceptable level, the output of the comparator goes from the low state (a few millivolts) to the high state (near the supply potential, which is typically 6.8 V for microphone power). The switching of the comparator output to the high state triggers a tactile alarm in the form of a vibration in the mask, generated by a small 1.3-Vdc pager motor spinning an eccentric mass at a rate between 8,000 and 10,000 rpm. The sensation of the mask vibrating against the crewmember s nose is very effective at alerting the crewmember, who may already be groggy from hypoxia and is immersed in an environment that is saturated with visual cues and sounds. Indeed, the sensation is one of rudeness, but such rudeness could be what is needed to stimulate the crewmember to take corrective action in a life-threatening situation.

Uniform distributions of glucose oxidation and oxygen extraction in gray matter of normal human brain: No evidence of regional differences of aerobic glycolysis.

Science.gov (United States)

Hyder, Fahmeed; Herman, Peter; Bailey, Christopher J; Møller, Arne; Globinsky, Ronen; Fulbright, Robert K; Rothman, Douglas L; Gjedde, Albert

2016-05-01

Regionally variable rates of aerobic glycolysis in brain networks identified by resting-state functional magnetic resonance imaging (R-fMRI) imply regionally variable adenosine triphosphate (ATP) regeneration. When regional glucose utilization is not matched to oxygen delivery, affected regions have correspondingly variable rates of ATP and lactate production. We tested the extent to which aerobic glycolysis and oxidative phosphorylation power R-fMRI networks by measuring quantitative differences between the oxygen to glucose index (OGI) and the oxygen extraction fraction (OEF) as measured by positron emission tomography (PET) in normal human brain (resting awake, eyes closed). Regionally uniform and correlated OEF and OGI estimates prevailed, with network values that matched the gray matter means, regardless of size, location, and origin. The spatial agreement between oxygen delivery (OEF≈0.4) and glucose oxidation (OGI ≈ 5.3) suggests that no specific regions have preferentially high aerobic glycolysis and low oxidative phosphorylation rates, with globally optimal maximum ATP turnover rates (VATP ≈ 9.4 µmol/g/min), in good agreement with (31)P and (13)C magnetic resonance spectroscopy measurements. These results imply that the intrinsic network activity in healthy human brain powers the entire gray matter with ubiquitously high rates of glucose oxidation. Reports of departures from normal brain-wide homogeny of oxygen extraction fraction and oxygen to glucose index may be due to normalization artefacts from relative PET measurements. © The Author(s) 2016.

Evaluation of image quality and patient safety: paired inspiratory and expiratory MDCT assessment of tracheobronchomalacia in paediatric patients under general anaesthesia with breath-hold technique

International Nuclear Information System (INIS)

Lee, Edward Y.; Bastos, Maria d' Almeida; Stark, Cynthia; Carrier, Maureen; Zurakowski, David; Mason, Keira P.

2012-01-01

The purpose of our investigation was to evaluate image quality and patient safety in infants and young children who required general anaesthesia with breath-hold technique for paired inspiratory and expiratory multidetector CT (MDCT) assessment of tracheobronchomalacia (TBM). Our hospital's institutional review board approved the review of radiological and clinical data of a consecutive series of 20 paediatric patients who underwent MDCT under general anaesthesia with breath-hold technique for evaluation of TBM from May 2006 to December 2008. For each MDCT study, two fellowship-trained paediatric radiologists reviewed the inspiratory and expiratory MDCT images in an independent, randomised and blinded fashion for the presence of motion artefact at three anatomic levels (upper, middle and lower central airways). The clinical history and anaesthesia outcome, including the occurrence of any adverse events during or following the MDCT examinations until discharge, were also reviewed and recorded. The study population consisted of 20 infants and young children (13 boys/seven girls, mean age 1.7 ± 1.4 years, age range 11 days to 4 years). The imaging quality of all 20 MDCT studies was diagnostic with no motion artefact in 16 studies (80%) and minimal motion artefact in the remaining four studies (20%). Minor adverse events occurred in three patients (15%) that included one patient (5%) with a brief (<60 s) oxygen desaturation during MDCT study, which resolved with oxygen, and two patients (5%) with either a brief (<60 s) oxygen desaturation (n = 1, 5%) or cough (n = 1, 5%) during recovery period, which were completely resolved with oxygen and dexamethasone, respectively. Diagnostic quality paired inspiratory and expiratory MDCT imaging with breath-hold technique can be safely performed in infants and young children under general anaesthesia for evaluation of TBM.

The effect of CPAP treatment on venous lactate and arterial blood gas among obstructive sleep apnea syndrome patients.

Science.gov (United States)

Lin, Ting; Huang, Jie-Feng; Lin, Qi-Chang; Chen, Gong-Ping; Wang, Bi-Ying; Zhao, Jian-Ming; Qi, Jia-Chao

2017-05-01

The aim of this observational study was to investigate the influence of continuous positive airway pressure (CPAP) on arterial blood gas and venous lactate, markers of tissue hypoxia, among obstructive sleep apnea syndrome (OSAS) patients, and determine the risk factor of serum lactate and hydrogen ion concentration (PH) in OSAS patients. One-hundred and nine patients with newly diagnosed OSAS were enrolled in the study. All individuals were treated with CPAP for one night. Venous lactate and arterial blood gas were gathered from all subjects in the morning at the end of polysomnography and the next morning after CPAP treatment. Of the 109 selected subjects, the average lactate level was 2.23 ± 0.59 mmol/L, and the mean PH, PaO 2 , and PaCO 2 were 7.380 ± 0.23, 88.14 ± 17.83 mmHg, and 38.70 ± 4.28 mmHg, respectively. Compared to baseline, lactic acid significantly decreased (2.10 ± 0.50 mmol/L, p = 0.03), while PH increased (7.388 ± 0.27, p treatment. In addition, neck circumference and the polysomnographic parameters, including apnea-hypopnea index, oxygen desaturation index (ODI), mean oxygen saturation (SpO 2 ), and the percentage of sleep time with SpO 2 treatment could reduce serum lactate and increase PH in OSAS patients and might alleviate acid-base balance disorders in OSAS. Furthermore, TS90 % was a risk factor for elevated lactate, and age was independently associated with PH.

Total quality index of Agaricus bisporus mushrooms packed in modified atmosphere.

Science.gov (United States)

Djekic, Ilija; Vunduk, Jovana; Tomašević, Igor; Kozarski, Maja; Petrovic, Predrag; Niksic, Miomir; Pudja, Predrag; Klaus, Anita

2017-07-01

The aim of this study was to develop a total quality index and examine the effects of modified atmosphere packaging (MAP) on the quality of Agaricus bisporus mushrooms stored for 22 days at 4 °C. Mushrooms were packaged under three MAPs: high nitrogen packaging (HNP), low carbon dioxide packaging (LCP) and low oxygen packaging (LOP). Passive MAP with air inside initially was used as the atmosphere treatment (AIR). This research revealed two phases in quality deterioration of A. bisporus mushrooms. During the first week, most of the quality parameters were not statistically different. Thereafter, odor intensities were stronger for all four types of packaging. Color difference and browning index values showed significantly lower color changes for AIR and LOP compared with HNP and LCP mushrooms. The best total quality index was calculated for LOP, followed by LCP and AIR. The findings of this study are useful with respect to examining two-component MAPs, separating the limiting factors (O 2 and CO 2 ) and evaluating quality deterioration effects and the total quality index of A. bisporus mushrooms. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

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.

Density functional theory study the effects of oxygen-containing functional groups on oxygen molecules and oxygen atoms adsorbed on carbonaceous materials.

Science.gov (United States)

Qi, Xuejun; Song, Wenwu; Shi, Jianwei

2017-01-01

Density functional theory was used to study the effects of different types of oxygen-containing functional groups on the adsorption of oxygen molecules and single active oxygen atoms on carbonaceous materials. During gasification or combustion reactions of carbonaceous materials, oxygen-containing functional groups such as hydroxyl(-OH), carbonyl(-CO), quinone(-O), and carboxyl(-COOH) are often present on the edge of graphite and can affect graphite's chemical properties. When oxygen-containing functional groups appear on a graphite surface, the oxygen molecules are strongly adsorbed onto the surface to form a four-member ring structure. At the same time, the O-O bond is greatly weakened and easily broken. The adsorption energy value indicates that the adsorption of oxygen molecules changes from physisorption to chemisorption for oxygen-containing functional groups on the edge of a graphite surface. In addition, our results indicate that the adsorption energy depends on the type of oxygen-containing functional group. When a single active oxygen atom is adsorbed on the bridge site of graphite, it gives rise to a stable epoxy structure. Epoxy can cause deformation of the graphite lattice due to the transition of graphite from sp2 to sp3 after the addition of an oxygen atom. For quinone group on the edge of graphite, oxygen atoms react with carbon atoms to form the precursor of CO2. Similarly, the single active oxygen atoms of carbonyl groups can interact with edge carbon atoms to form the precursor of CO2. The results show that oxygen-containing functional groups on graphite surfaces enhance the activity of graphite, which promotes adsorption on the graphite surface.

Primary caregivers of in-home oxygen-dependent children: predictors of stress based on characteristics, needs and social support.

Science.gov (United States)

Wang, Kai-Wei K; Lin, Hung-Ching; Lee, Chin-Ting; Lee, Kuo-Sheng

2016-07-01

To identify the predictors of primary caregivers' stress in caring for in-home oxygen-dependent children by examining the association between their levels of stress, caregiver needs and social support. Increasing numbers of primary caregivers of oxygen-dependent children experience caregiving stress that warrants investigation. The study used a cross-sectional design with three psychometric scales - Modified-Parenting Stress Index, Caregiver Needs Scale and Social Support Index. The data collected during 2010-2011 were from participants who were responsible for their child's care that included oxygen therapy for ≧6 hours/day; the children's ages ranged from 3 months-16 years. Descriptive statistics and multivariable linear regression were used. A total of 104 participants (M = 34, F = 70) were recruited, with an average age of 39·7 years. The average age of the oxygen-dependent children was 6·68 years and their daily use of oxygen averaged 11·39 hours. The caregivers' overall levels of stress were scored as high and information needs were scored as the highest. The most available support from family and friends was emotional support. Informational support was mostly received from health professionals, but both instrumental and emotional support were important. Levels of stress and caregiver needs were significantly correlated. Multivariable linear regression analyses identified three risk factors predicting stress, namely, the caregiver's poor health status, the child's male gender and the caregiver's greater financial need. To support these caregivers, health professionals can maintain their health status and provide instrumental, emotional, informational and financial support. © 2016 John Wiley & Sons Ltd.

Research progress of on-line automatic monitoring of chemical oxygen demand (COD) of water

Science.gov (United States)

Cai, Youfa; Fu, Xing; Gao, Xiaolu; Li, Lianyin

2018-02-01

With the increasingly stricter control of pollutant emission in China, the on-line automatic monitoring of water quality is particularly urgent. The chemical oxygen demand (COD) is a comprehensive index to measure the contamination caused by organic matters, and thus it is taken as one important index of energy-saving and emission reduction in China’s “Twelve-Five” program. So far, the COD on-line automatic monitoring instrument has played an important role in the field of sewage monitoring. This paper reviews the existing methods to achieve on-line automatic monitoring of COD, and on the basis, points out the future trend of the COD on-line automatic monitoring instruments.

Further Controversies About Brain Tissue Oxygenation Pressure-Reactivity After Traumatic Brain Injury

DEFF Research Database (Denmark)

Andresen, Morten; Donnelly, Joseph; Aries, Marcel

2018-01-01

arterial pressure and intracranial pressure. A new ORx index based on brain tissue oxygenation and cerebral perfusion pressure (CPP) has been proposed that similarly allows for evaluation of cerebrovascular reactivity. Conflicting results exist concerning its clinical utility. METHODS: Retrospective......BACKGROUND: Continuous monitoring of cerebral autoregulation is considered clinically useful due to its ability to warn against brain ischemic insults, which may translate to a relationship with adverse outcome. It is typically performed using the pressure reactivity index (PRx) based on mean...... analysis was performed in 85 patients with traumatic brain injury (TBI). ORx was calculated using three time windows of 5, 20, and 60 min. Correlation coefficients and individual "optimal CPP" (CPPopt) were calculated using both PRx and ORx, and relation to patient outcome investigated. RESULTS...

Bayesian prediction of microbial oxygen requirement [v1; ref status: indexed, http://f1000r.es/1m6

Directory of Open Access Journals (Sweden)

Dan B. Jensen

2013-09-01

Full Text Available Background: Prediction of the optimal habitat conditions for a given bacterium, based on genome sequence alone would be of value for scientific as well as industrial purposes. One example of such a habitat adaptation is the requirement for oxygen. In spite of good genome data availability, there have been only a few prediction attempts of bacterial oxygen requirements, using genome sequences. Here, we describe a method for distinguishing aerobic, anaerobic and facultative anaerobic bacteria, based on genome sequence-derived input, using naive Bayesian inference. In contrast, other studies found in literature only demonstrate the ability to distinguish two classes at a time. Results: The results shown in the present study are as good as or better than comparable methods previously described in the scientific literature, with an arguably simpler method, when results are directly compared. This method further compares the performance of a single-step naive Bayesian prediction of the three included classifications, compared to a simple Bayesian network with two steps. A two-step network, distinguishing first respiring from non-respiring organisms, followed by the distinction of aerobe and facultative anaerobe organisms within the respiring group, is found to perform best. Conclusions: A simple naive Bayesian network based on the presence or absence of specific protein domains within a genome is an effective and easy way to predict bacterial habitat preferences, such as oxygen requirement.

Neonatal and pediatric extracorporeal membrane oxygenation in developing Latin American countries.

Science.gov (United States)

Kattan, Javier; González, Álvaro; Castillo, Andrés; Caneo, Luiz Fernando

To review the principles of neonatal-pediatric extracorporeal membrane oxygenation therapy, prognosis, and its establishment in limited resource-limited countries in Latino America. The PubMed database was explored from 1985 up to the present, selecting from highly-indexed and leading Latin American journals, and Extracorporeal Life Support Organization reports. Extracorporeal membrane oxygenation provides "time" for pulmonary and cardiac rest and for recovery. It is used in the neonatal-pediatric field as a rescue therapy for more than 1300 patients with respiratory failure and around 1000 patients with cardiac diseases per year. The best results in short- and long-term survival are among patients with isolated respiratory diseases, currently established as a standard therapy in referral centers for high-risk patients. The first neonatal/pediatric extracorporeal membrane oxygenation Program in Latin America was established in Chile in 2003, which was also the first program in Latin America to affiliate with the Extracorporeal Life Support Organization. New extracorporeal membrane oxygenation programs have been developed in recent years in referral centers in Argentina, Colombia, Brazil, Mexico, Perú, Costa Rica, and Chile, which are currently funding the Latin American Extracorporeal Life Support Organization chapter. The best results in short- and long-term survival are in patients with isolated respiratory diseases. Today extracorporeal membrane oxygenation therapy is a standard therapy in some Latin American referral centers. It is hoped that these new extracorporeal membrane oxygenation centers will have a positive impact on the survival of newborns and children with respiratory or cardiac failure, and that they will be available for an increasing number of patients from this region in the near future. Copyright © 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Neonatal and pediatric extracorporeal membrane oxygenation in developing Latin American countries

Directory of Open Access Journals (Sweden)

Javier Kattan

Full Text Available Abstract Objective: To review the principles of neonatal-pediatric extracorporeal membrane oxygenation therapy, prognosis, and its establishment in limited resource-limited countries in Latino America. Sources: The PubMed database was explored from 1985 up to the present, selecting from highly-indexed and leading Latin American journals, and Extracorporeal Life Support Organization reports. Summary of the findings: Extracorporeal membrane oxygenation provides “time” for pulmonary and cardiac rest and for recovery. It is used in the neonatal-pediatric field as a rescue therapy for more than 1300 patients with respiratory failure and around 1000 patients with cardiac diseases per year. The best results in short- and long-term survival are among patients with isolated respiratory diseases, currently established as a standard therapy in referral centers for high-risk patients. The first neonatal/pediatric extracorporeal membrane oxygenation Program in Latin America was established in Chile in 2003, which was also the first program in Latin America to affiliate with the Extracorporeal Life Support Organization. New extracorporeal membrane oxygenation programs have been developed in recent years in referral centers in Argentina, Colombia, Brazil, Mexico, Perú, Costa Rica, and Chile, which are currently funding the Latin American Extracorporeal Life Support Organization chapter. Conclusions: The best results in short- and long-term survival are in patients with isolated respiratory diseases. Today extracorporeal membrane oxygenation therapy is a standard therapy in some Latin American referral centers. It is hoped that these new extracorporeal membrane oxygenation centers will have a positive impact on the survival of newborns and children with respiratory or cardiac failure, and that they will be available for an increasing number of patients from this region in the near future.

Effects of the oxygen fraction and substrate bias power on the electrical and optical properties of silicon oxide films by plasma enhanced chemical vapour deposition using TMOS/O2 gas

International Nuclear Information System (INIS)

Bang, S B; Chung, T H; Kim, Y; Kang, M S; Kim, J K

2004-01-01

Thin oxide films are deposited from tetramethoxysilane in an inductively coupled oxygen glow discharge supplied with radio frequency power. The chemical bonding states of deposited films are analysed by Fourier transform infrared spectroscopy. The deposition rate and optical properties are determined from spectroscopic ellipsometry. Capacitance-voltage measurements are performed in MOS capacitors to obtain the electrical properties of the deposited films. With these tools, the effects of the substrate bias power and the oxygen mole fraction in the gas on the properties of the film are investigated. The refractive index first decreases with an increase in the oxygen mole fraction, and then increases again, showing a behaviour opposite to that of the deposition rate. The deposition rate increases with increasing substrate bias power and then saturates, while the refractive index increases slightly with an increase in the substrate bias power. The fixed oxide charge density decreases with increasing oxygen fraction and with increasing substrate bias power, while the interface trap density increases with increasing oxygen fraction and with increasing substrate bias power

The safety and efficacy of intranasal midazolam sedation combined with inhalation sedation with nitrous oxide and oxygen in paediatric dental patients as an alternative to general anaesthesia.

Science.gov (United States)

Wood, Michael

2010-01-01

Conscious Decision' was published in 2000 by the Department of Health, effectively ending the provision of dental general anaesthesia (DGA) outside the hospital environment. Other aspects of dental anxiety and behavioural management and sedation techniques were encouraged before the decision to refer for a DGA was reached. Although some anxious children may be managed with relative analgesia (RA), some may require different sedation techniques for dentists to accomplish dental treatment. Little evidence has been published in the UK to support the use of alternative sedation techniques in children. This paper presents another option using an alternative conscious sedation technique. to determine whether a combination of intranasal midazolam (IN) and inhalation sedation with nitrous oxide and oxygen is a safe and practical alternative to DGA. A prospective clinical audit of 100 cases was carried out on children referred to a centre for DGA. 100 children between 3 and 13 years of age who were referred for DGA were treated using this technique. Sedation was performed by intranasal midazolam followed by titrating a mixture of nitrous oxide and oxygen. A range of dental procedures was carried out while the children were sedated. Parents were present during the dental treatment. Data related to the patient, dentistry and treatment as well as sedation variables were collected at the treatment visit and a telephonic post-operative assessment from the parents was completed a week later. It was found that 96% of the required dental treatment was completed successfully using this technique, with parents finding this technique acceptable in 93% of cases. 50% of children found the intranasal administration of the midazolam acceptable. There was no clinically relevant oxygen desaturation during the procedure. Patients were haemodynamically stable and verbal contact was maintained throughout the procedure. In selected cases this technique provides a safe and effective alternative

Relationship between pre-extubation positive endexpiratory pressure and oxygenation after coronary artery bypass grafting

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Reijane Oliveira Lima

2015-08-01

Full Text Available Abstract Introduction After removal of endotracheal tube and artificial ventilation, ventilatory support should be continued, offering oxygen supply to ensure an arterial oxygen saturation close to physiological. Objective: The aim of this study was to investigate the effects of positive-end expiratory pressure before extubation on the oxygenation indices of patients undergoing coronary artery bypass grafting. Methods: A randomized clinical trial with seventy-eight patients undergoing coronary artery bypass grafting divided into three groups and ventilated with different positive-end expiratory pressure levels prior to extubation: Group A, 5 cmH2O (n=32; Group B, 8 cmH2O (n=26; and Group C, 10 cmH2O (n=20. Oxygenation index data were obtained from arterial blood gas samples collected at 1, 3, and 6 h after extubation. Patients with chronic pulmonary disease and those who underwent off-pump, emergency, or combined surgeries were excluded. For statistical analysis, we used Shapiro-Wilk, G, Kruskal-Wallis, and analysis of variance tests and set the level of significance at P<0.05. Results Groups were homogenous with regard to demographic, clinical, and surgical variables. There were no statistically significant differences between groups in the first 6 h after extubation with regard to oxygenation indices and oxygen therapy utilization. Conclusion: In this sample of patients undergoing coronary artery bypass grafting, the use of different positive-end expiratory pressure levels before extubation did not affect gas exchange or oxygen therapy utilization in the first 6 h after endotracheal tube removal.

Oxygen permeation through oxygen ion oxide-noble metal dual phase composites

NARCIS (Netherlands)

Chen, C.S.; Chen, C.S.; Kruidhof, H.; Bouwmeester, Henricus J.M.; Verweij, H.; Burggraaf, Anthonie; Burggraaf, A.J.

1996-01-01

Oxygen permeation behaviour of three composites, yttria-stabilized zirconia-palladium, erbia-stabilized bismuth oxidenoble metal (silver, gold) was studied. Oxygen permeation measurements were performed under controlled oxygen pressure gradients at elevated temperatures. Air was supplied at one side

Compound effects of inhaling pure oxygen and lifting height on ear baric function in a hypobaric chamber

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Dong-qing WEN

2017-02-01

Full Text Available Objective　To compare the ear baric function between 4000m altitude chamber test with inhaling air and 6900m altitude chamber test with inhaling pure oxygen. Methods　Eleven healthy male volunteers attended two tests as two groups by self-comparison. As the air group the volunteers inhaled air at 4000m, while as the pure oxygen group they inhaled pure oxygen at 6900m altitude, and the time interval between the two tests was more than two weeks. During the test, the volunteers breathed air or pure oxygen at random for 1h, and then were exposed at a speed of 20m/s to the target altitude for 5min. Hereafter they were sent back to the ground at the same speed. The changes of subjective symptoms, degree of tympanic congestion, acoustic immitance index and pure-tone auditory threshold were recorded before and after the test. The acoustic impedance index and pure-tone threshold were statistically analyzed. Results　Four volunteers (4 ears in air group and 7 volunteers (7 ears in pure oxygen group reported ear pain in altitude chamber exposures, respectively. The pain-triggering altitude was higher in the pure oxygen group. Immediately after tests, there were 3 (3 ears and 5 volunteers (5 ears with Ⅲ degree congestion of the tympanic membrane in the two groups respectively. Four volunteers (6 ears developed gradually aggravated hemorrhages after altitude exposure. And the tympanic membrane congestion difference between groups was statistically significant at 3 and 24h after tests (P<0.01. The type A tympanogram appeared in 11 (15 ears and 11 (14 ears volunteers respectively immediately after tests. The increase of static compliance value was significantly greater in pure oxygen group than in air group immediately after tests (P<0.05, the decrease of middle ear pressure was more significant in pure oxygen group than in air group at 3 and 24h after tests (P<0.05. Both the two altitude exposure tests resulted in eustachian tube dysfunction. At 3 and

The oxygen effect and adaptive response of cells. Report 3. Simulation of respiratory oxygenation and oxygen permeability of cells

International Nuclear Information System (INIS)

Ehpshtejn, I.M.

1978-01-01

Variations in the oxygen concentration in extracellural [O 2 ] 0 and intracellular [Osub(2)]sub(i) media of cells small in size (d = 2 ] 0 - t-curves). It is shown that the Value of [Osub(2)]sub(i) may be expressed by four variants of its functional dependence: (a) on enzymic reaction of oxygen consumption, (b) on the order of reaction with respect to oxygen, (c) on physiological parameters of cells, and (d) on characteristic oxygen concentrations in the system. Items (c) and (d) are based on the postulated diffusion-kinetic model of oxygen consumption by an idealized cell of small size that consists of a drop of homogenous solution of the respiratory enzyme which is characterized by an equivalent Michaelis constant. The drop is enveloped in a uniform membrane that possesses a definite diffuse resistance to oxygen

Correlating two-photon excited fluorescence imaging of breast cancer cellular redox state with seahorse flux analysis of normalized cellular oxygen consumption

Science.gov (United States)

Hou, Jue; Wright, Heather J.; Chan, Nicole; Tran, Richard; Razorenova, Olga V.; Potma, Eric O.; Tromberg, Bruce J.

2016-06-01

Two-photon excited fluorescence (TPEF) imaging of the cellular cofactors nicotinamide adenine dinucleotide and oxidized flavin adenine dinucleotide is widely used to measure cellular metabolism, both in normal and pathological cells and tissues. When dual-wavelength excitation is used, ratiometric TPEF imaging of the intrinsic cofactor fluorescence provides a metabolic index of cells-the "optical redox ratio" (ORR). With increased interest in understanding and controlling cellular metabolism in cancer, there is a need to evaluate the performance of ORR in malignant cells. We compare TPEF metabolic imaging with seahorse flux analysis of cellular oxygen consumption in two different breast cancer cell lines (MCF-7 and MDA-MB-231). We monitor metabolic index in living cells under both normal culture conditions and, for MCF-7, in response to cell respiration inhibitors and uncouplers. We observe a significant correlation between the TPEF-derived ORR and the flux analyzer measurements (R=0.7901, p<0.001). Our results confirm that the ORR is a valid dynamic index of cell metabolism under a range of oxygen consumption conditions relevant for cancer imaging.

Proterozoic atmospheric oxygen

DEFF Research Database (Denmark)

Canfield, Donald Eugene

2014-01-01

This article is concerned with the evolution of atmospheric oxygen concentrations through the Proterozoic Eon. In particular, this article will seek to place the history of atmospheric oxygenation through the Proterozoic Eon in the context of the evolving physical environment including the history...... of continental growth and volcanic outgassing, as well as biogeochemical processing of elements within the oceans. The author will seek to explore constraints on the history of oxygenation and understand which processes have regulated oxygen through this eon....

Generation of intensity covariations of the oxygen green and red lines in the nightglow

Science.gov (United States)

Misawa, K.; Takeuchi, I.; Kato, Y.; Aoyama, I.

1984-02-01

The cause of intensity covariations of the oxygen green and red lines is studied. Intensity covariations are compared with the auroral-electrojet-activity index AE, the substorm Pi2, and the magnetogram. It is suggested that intensity covariations or double-intensity maxima of the red line occur in association with intense auroral substorms, and that they are the direct experimental evidences of Testud's theory (1973).

Oxygen respiration rates of benthic foraminifera as measured with oxygen microsensors

DEFF Research Database (Denmark)

Geslin, E.; Risgaard-Petersen, N.; Lombard, Fabien

2011-01-01

of the foraminiferal specimens. The results show a wide range of oxygen respiration rates for the different species (from 0.09 to 5.27 nl cell−1 h−1) and a clear correlation with foraminiferal biovolume showed by the power law relationship: R = 3.98 10−3 BioVol0.88 where the oxygen respiration rate (R) is expressed......Oxygen respiration rates of benthic foraminifera are still badly known, mainly because they are difficult to measure. Oxygen respiration rates of seventeen species of benthic foraminifera were measured using microelectrodes and calculated on the basis of the oxygen fluxes measured in the vicinity...... groups (nematodes, copepods, ostracods, ciliates and flagellates) suggests that benthic foraminifera have a lower oxygen respiration rates per unit biovolume. The total contribution of benthic foraminifera to the aerobic mineralisation of organic matter is estimated for the studied areas. The results...

A model for oxygen conservation associated with titration during pediatric oxygen therapy.

Directory of Open Access Journals (Sweden)

Grace Wu

Full Text Available Continuous oxygen treatment is essential for managing children with hypoxemia, but access to oxygen in low-resource countries remains problematic. Given the high burden of pneumonia in these countries and the fact that flow can be gradually reduced as therapy progresses, oxygen conservation through routine titration warrants exploration.To determine the amount of oxygen saved via titration during oxygen therapy for children with hypoxemic pneumonia.Based on published clinical data, we developed a model of oxygen flow rates needed to manage hypoxemia, assuming recommended flow rate at start of therapy, and comparing total oxygen used with routine titration every 3 minutes or once every 24 hours versus no titration.Titration every 3 minutes or every 24 hours provided oxygen savings estimated at 11.7% ± 5.1% and 8.1% ± 5.1% (average ± standard error of the mean, n = 3, respectively. For every 100 patients, 44 or 30 kiloliters would be saved-equivalent to 733 or 500 hours at 1 liter per minute.Ongoing titration can conserve oxygen, even performed once-daily. While clinical validation is necessary, these findings could provide incentive for the routine use of pulse oximeters for patient management, as well as further development of automated systems.

ASSESSMENT OF PHYSICAL SKILLS TO THE STUDENT FITNESS INDEX

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Ratko Pavlović

2011-09-01

Full Text Available A very common way of assessing the state of physical abilities is to determine on the basis of diagnostic tests, and they give us the necessary information when it comes to general skills defined population. This evaluation is usually performed diagnostic tests in the laboratory. However, reliable data are available on the performance of some field tests. Depending on field conditions, very often is done using estimates of general ability test, 2km walking UKK. To perform this test shall include data on body height, weight, BMI-in, values, heart rate, time walking. Based on the formula and application of these data are obtained fitness value of the index by which to define the overall physical condition of patients. Also based on the formula to obtain indicators on maximum oxygen consumption. The study comprised third-year students East Sarajevo, who held classes in subjects walking sports athletics, in order to determine their state of physical fitness index based on fitness.

Influence of cerebrovascular arteriosclerosis on cerebral oxygenation during exercise

International Nuclear Information System (INIS)

Nagayama, Osamu; Koike, Akira; Hoshimoto, Masayo; Yamaguchi, Kaori; Tajima, Akihiko; Goda, Ayumi; Uejima, Tokuhisa; Aizawa, Tadanori; Itoh, Haruki

2007-01-01

Although it is assumed that cerebral oxygenation during exercise is influenced by both cardiopulmonary function and cerebrovascular arteriosclerosis, the latter factor has not been fully clarified. In the present study the relationship between the degree of cerebrovascular arteriosclerosis and cerebral oxygenation during exercise was investigated. A total of 109 patients (69 patients with coronary artery disease, 40 patients with hypertensive heart disease) (61.7±9.7 years) performed a symptom-limited exercise test with respiratory gas measurements (CPX). From the respiratory gas analysis, peak O 2 uptake (VO 2 ), the slope of the increase in VO 2 to the increase in work rate (ΔVO 2 /ΔWR), and the slope of the increase in ventilation to the increase in CO 2 output (VE/VCO 2 slope) were calculated. Oxyhemoglobin (O 2 Hb) at the forehead was monitored using near-infrared spectroscopy. The brain ischemic score was counted based upon fluid-attenuated inversion recovery images of magnetic resonance imaging and expressed from 0 to 4. When compared with patients with a lower ischemic score ( 2 Hb during exercise (-1.08±2.7 vs 0.77±4.1 μmol/L, p=0.011). Of brain ischemic score, left ventricular ejection fraction, peak VO 2 , ΔVO 2 /ΔWR, and the VE/VCO 2 slope, ΔVO 2 /ΔWR was found to be the sole independent index determining cerebral O 2 Hb during exercise. The CPX parameters were also significantly related to the degree of cerebrovascular arteriosclerosis. Although cerebral oxygenation during exercise is mainly related to cardiopulmonary function, the degree of cerebrovascular arteriosclerosis partly influences cerebral oxygenation in patients with risk factors for atherosclerosis. (author)

Tae-Eum Type as an Independent Risk Factor for Obstructive Sleep Apnea

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Seung Ku Lee

2013-01-01

Full Text Available Obstructive sleep apnea (OSA is prevalent and associated with several kinds of chronic diseases. There has been evidence that a specific type of Sasang constitution is a risk factor for metabolic and cardiovascular diseases that can be found in patients with OSA, but there are no studies that address the association between the Sasang constitution type (SCT and OSA. The purpose of this study was to investigate the association between the SCT and OSA. A total of 652 participants were included. All participants were examined for demographic information, medical history, and completed an interviewer-administered questionnaire on life style and sleep-related variables. Biochemical analyses were performed to determine the glucose and lipid profiles. An objective recording of OSA was done with an unattended home PSG using an Embla portable device. The apnea-hypopnea index (AHI and oxygen desaturation index (ODI were significantly higher in the Tae-eum (TE type as compared to the So-eum (SE and the So-yang (SY types. Even after adjusting for confounding variables, the TE type still had a 2.34-fold (95% CI, 1.11–4.94; P=0.0262 increased risk for OSA. This population-based cohort study found that the TE constitutional type is an independent risk factor for the development of OSA.

Colour vision and light sensitivity in tunnel workers previously exposed to acrylamide and N-methylolacrylamide containing grouting agents.

Science.gov (United States)

Goffeng, Lars Ole; Kjuus, Helge; Heier, Mona Skard; Alvestrand, Monica; Ulvestad, Bente; Skaug, Vidar

2008-01-01

The aim of the study was to examine possible persisting visual system effects in tunnel workers previously exposed to acrylamide and N-methylolacrylamide during grouting work. Visual field light sensitivity threshold and colour vision has been examined among 44 tunnel workers 2-10 years after exposure to acrylamide and N-methylolacrylamide containing grouting agents. Forty-four tunnel workers not involved in grouting operations served as control group. Information on exposure and background variables was obtained for all participants from a questionnaire. Visual light sensitivity threshold was measured using Humphrey Visual Field Static Perimeter 740, program 30-2 Fastpack, with red stimuli on white background, and colour vision, using Lanthony D-15 Desaturated Color test. Based on D-15d test results, colour confusion index (CCI), and a severity index (C-index) was calculated. The exposed group had a significantly higher threshold for detecting single stimuli in all parts of the inner 30 degrees of the visual field compared to the control group. The foveal threshold group difference was 1.4 dB (p=0.002) (mean value, both eyes). On the Lanthony 15 Hue Desaturated test, the exposed subjects made more errors in sorting blue colours, and a statistically significant increase in C-index was observed. Surrogate measures for duration and intensity of exposure gave no further improvement of the model. The results indicate slightly reduced light sensitivity and reduced colour discrimination among the exposed subjects compared to the controls. The findings may be due to previous exposure to acrylamide containing grouts among the tunnel workers.

Artificial oxygen transport protein

Science.gov (United States)

Dutton, P. Leslie

2014-09-30

This invention provides heme-containing peptides capable of binding molecular oxygen at room temperature. These compounds may be useful in the absorption of molecular oxygen from molecular oxygen-containing atmospheres. Also included in the invention are methods for treating an oxygen transport deficiency in a mammal.

Aircraft Oxygen Generation

Science.gov (United States)

2012-02-01

An Oxygen Enriched Air System for the AV-8A Harrier (NADC-81198-60).” 70 Horch , T., et. al. “The F-16 Onboard Oxygen Generating System: Performance...Only and Safety Privileged). Horch , T., Miller, R., Bomar, J., Tedor, J., Holden, R., Ikels, K., & Lozano, P. (1983). The F-16 Onboard Oxygen

High-precision diode-laser-based temperature measurement for air refractive index compensation

International Nuclear Information System (INIS)

Hieta, Tuomas; Merimaa, Mikko; Vainio, Markku; Seppae, Jeremias; Lassila, Antti

2011-01-01

We present a laser-based system to measure the refractive index of air over a long path length. In optical distance measurements, it is essential to know the refractive index of air with high accuracy. Commonly, the refractive index of air is calculated from the properties of the ambient air using either Ciddor or Edlen equations, where the dominant uncertainty component is in most cases the air temperature. The method developed in this work utilizes direct absorption spectroscopy of oxygen to measure the average temperature of air and of water vapor to measure relative humidity. The method allows measurement of temperature and humidity over the same beam path as in optical distance measurement, providing spatially well-matching data. Indoor and outdoor measurements demonstrate the effectiveness of the method. In particular, we demonstrate an effective compensation of the refractive index of air in an interferometric length measurement at a time-variant and spatially nonhomogeneous temperature over a long time period. Further, we were able to demonstrate 7 mK RMS noise over a 67 m path length using a 120 s sample time. To our knowledge, this is the best temperature precision reported for a spectroscopic temperature measurement.

Oxygen enrichment incineration

International Nuclear Information System (INIS)

Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, Joon Hyung

2000-10-01

Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested

Oxygen enrichment incineration

Energy Technology Data Exchange (ETDEWEB)

Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, Joon Hyung

2000-10-01

Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested.

Effects of oxygen concentration on atmospheric pressure dielectric barrier discharge in Argon-Oxygen Mixture

Science.gov (United States)

Li, Xuechun; Li, Dian; Wang, Younian

2016-09-01

A dielectric barrier discharge (DBD) can generate a low-temperature plasma easily at atmospheric pressure and has been investigated for applications in trials in cancer therapy, sterilization, air pollution control, etc. It has been confirmed that reactive oxygen species (ROS) play a key role in the processes. In this work, we use a fluid model to simulate the plasma characteristics for DBD in argon-oxygen mixture. The effects of oxygen concentration on the plasma characteristics have been discussed. The evolution mechanism of ROS has been systematically analyzed. It was found that the ground state oxygen atoms and oxygen molecular ions are the dominated oxygen species under the considered oxygen concentrations. With the oxygen concentration increasing, the densities of electrons, argon atomic ions, resonance state argon atoms, metastable state argon atoms and excited state argon atoms all show a trend of decline. The oxygen molecular ions density is high and little influenced by the oxygen concentration. Ground state oxygen atoms density tends to increase before falling. The ozone density increases significantly. Increasing the oxygen concentration, the discharge mode begins to change gradually from the glow discharge mode to Townsend discharge mode. Project supported by the National Natural Science Foundation of China (Grant No. 11175034).

Limitations of potentiometric oxygen sensors operating at low oxygen levels

DEFF Research Database (Denmark)

Lund, Anders; Jacobsen, Torben; Hansen, Karin Vels

2011-01-01

The electrochemical processes that limit the range of oxygen partial pressures in which potentiometric oxygen sensors can be used, were analysed using a theoretical and an experimental approach. Electrochemical impedance spectroscopy was performed on porous Pt/yttria stabilised zirconia (YSZ......) electrodes between 10−6 and 0.2 bar and at temperatures between 500 and 950 °C. The flow of oxide ions and electron holes through a sensor cell, with a YSZ electrolyte, were calculated under similar conditions. The oxygen permeation of the sensor cell was insignificant at an oxygen partial pressure of 10......−6 bar for an inlet flow rate higher than 2 L h−1 between 600 and 800 °C. The polarisation resistance measured between 10−6 and 10−4 bar was found to be inversely proportional to the oxygen partial pressure, nearly temperature independent and inversely proportional to the inlet gas flow rate, which shows...

An equivalence study comparing nitrous oxide and oxygen with low-dose sevoflurane and oxygen as inhalation sedation agents in dentistry for adults.

Science.gov (United States)

Allen, M; Thompson, S

2014-11-01

The aim of this study was to examine whether sevoflurane in oxygen was equivalent to near equipotent concentrations of nitrous oxide in oxygen when used as an inhalation sedation agent in terms of patient and user acceptability. Forty anxious dental patients referred to the sedation suite at Cardiff University School of Dentistry received either nitrous oxide to a maximum concentration of 40% or sevoflurane to a maximum concentration of 0.3% for a routine maxillary plastic restoration with articaine infiltration local analgesia. The inhalation sedation agent to be administered was chosen by a random number allocator. Measurements of blood pressure, oxygen saturation, heart rate, respiratory rate and bispectral index were recorded every 5 minutes. At the end of the treatment episode the patient, the operator and an observer who was unaware of the agent used, recorded their impressions about the episode by completing questionnaires. In the doses used in this study, sevoflurane was found to be as effective as an inhalation sedation agent as the standard dose of nitrous oxide used in normal inhalation sedation in the treatment of adult anxious dental patients. Sevoflurane in low concentrations is equivalent in effect to near equipotent concentrations of nitrous oxide. This would suggest that further research, perhaps with slightly higher concentrations of sevoflurane, is needed. If sevoflurane was shown to be acceptable at slightly higher concentrations, there is scope to explore the development of equipment specifically designed to deliver sevoflurane as an inhalation sedation agent in future.

Nature of oxygen donors and radiation defects in oxygen-doped germanium

International Nuclear Information System (INIS)

Fukuoka, Noboru; Atobe, Kozo; Honda, Makoto; Matsuda, Koji.

1991-01-01

The nature of oxygen donors and radiation defects in oxygen-doped germanium were studied through measurements of the infrared absorption spectrum, deep level transient spectroscopy spectrum and carrier concentration. It is revealed that a new donor is not formed in oxygen-doped germanium. An A-center (interstitial oxygen-vacancy pair) forms a complex with a thermal donor in its annealing stage at 60degC-140degC. The introduction rate of defects by 1.5 MeV electron irradiation was enhanced in thermal-donor-doped samples. (author)

Intraportal islet oxygenation.

Science.gov (United States)

Suszynski, Thomas M; Avgoustiniatos, Efstathios S; Papas, Klearchos K

2014-05-01

Islet transplantation (IT) is a promising therapy for the treatment of diabetes. The large number of islets required to achieve insulin independence limit its cost-effectiveness and the number of patients who can be treated. It is believed that >50% of islets are lost in the immediate post-IT period. Poor oxygenation in the early post-IT period is recognized as a possible reason for islet loss and dysfunction but has not been extensively studied. Several key variables affect oxygenation in this setting, including (1) local oxygen partial pressure (pO(2)), (2) islet oxygen consumption, (3) islet size (diameter, D), and (4) presence or absence of thrombosis on the islet surface. We discuss implications of oxygen-limiting conditions on intraportal islet viability and function. Of the 4 key variables, the islet size appears to be the most important determinant of the anoxic and nonfunctional islet volume fractions. Similarly, the effect of thrombus formation on the islet surface may be substantial. At the University of Minnesota, average size distribution data from clinical alloislet preparations (n = 10) indicate that >150-µm D islets account for only ~30% of the total islet number, but >85% of the total islet volume. This suggests that improved oxygen supply to the islets may have a profound impact on islet survivability and function since most of the β-cell volume is within large islets which are most susceptible to oxygen-limiting conditions. The assumption that the liver is a suitable islet transplant site from the standpoint of oxygenation should be reconsidered. © 2014 Diabetes Technology Society.

[Correlation between the inspired fraction of oxygen, maternal partial oxygen pressure, and fetal partial oxygen pressure during cesarean section of normal pregnancies].

Science.gov (United States)

Castro, Carlos Henrique Viana de; Cruvinel, Marcos Guilherme Cunha; Carneiro, Fabiano Soares; Silva, Yerkes Pereira; Cabral, Antônio Carlos Vieira; Bessa, Roberto Cardoso

2009-01-01

Despite changes in pulmonary function, maternal oxygenation is maintained during obstetric regional blocks. But in those situations, the administration of supplementary oxygen to parturients is a common practice. Good fetal oxygenation is the main justification; however, this has not been proven. The objective of this randomized, prospective study was to test the hypothesis of whether maternal hyperoxia is correlated with an increase in fetal gasometric parameters in elective cesarean sections. Arterial blood gases of 20 parturients undergoing spinal block with different inspired fractions of oxygen were evaluated and correlated with fetal arterial blood gases. An increase in maternal inspired fraction of oxygen did not show any correlation with an increase of fetal partial oxygen pressure. Induction of maternal hyperoxia by the administration of supplementary oxygen did not increase fetal partial oxygen pressure. Fetal gasometric parameters did not change even when maternal parameters changed, induced by hyperoxia, during cesarean section under spinal block.

The 1-Minute Sit-to-Stand Test in Adults With Cystic Fibrosis: Correlations With Cardiopulmonary Exercise Test, 6-Minute Walk Test, and Quadriceps Strength.

Science.gov (United States)

Gruet, Mathieu; Peyré-Tartaruga, Leonardo Alexandre; Mely, Laurent; Vallier, Jean-Marc

2016-12-01

Exercise testing is part of the regular assessment of patients with cystic fibrosis (CF). We aimed to evaluate (1) the convergent validity of the 1-min sit-to-stand (STS) test in CF by investigating its relationships with peak oxygen uptake (peak V̇ O 2 ), quadriceps strength, and quality of life and (2) to compare these associations with those of the 6-min walk test (6MWT). Twenty-five adults with CF (FEV 1 = 59 ± 24%) performed the STS test, the 6MWT, quadriceps strength assessment, and cardiopulmonary exercise test (CPET). Physical activity level, quality of life, and self-esteem were assessed by questionnaires. STS repetitions, 6-min walk distance, quadriceps strength, and peak V̇ O 2 were, respectively, 71 ± 12, 90 ± 10, 93 ± 29, and 62 ± 16% of predicted. The STS test had moderate associations with peak V̇ O 2 (r = 0.56, P = .004), quadriceps strength (r = 0.52, P = .008), and some questionnaire items (eg, perceived physical strength, r = 0.67, P test was strongly associated with oxygen desaturation during CPET (r = 0.80, P test as compared with CPET (P test cannot be used as a replacement for CPET to accurately assess peak exercise capacity in CF. The STS test may have utility in detecting patients with CF who may exhibit a high level of oxygen desaturation during heavy exercise. Further studies should identify the factors contributing to STS performance to confirm the potential interest of STS repetitions × body weight outcome as a useful submaximal exercise parameter in CF. Copyright © 2016 by Daedalus Enterprises.

Yeast alter micro-oxygenation of wine: oxygen consumption and aldehyde production.

Science.gov (United States)

Han, Guomin; Webb, Michael R; Richter, Chandra; Parsons, Jessica; Waterhouse, Andrew L

2017-08-01

Micro-oxygenation (MOx) is a common winemaking treatment used to improve red wine color development and diminish vegetal aroma, amongst other effects. It is commonly applied to wine immediately after yeast fermentation (phase 1) or later, during aging (phase 2). Although most winemakers avoid MOx during malolactic (ML) fermentation, it is often not possible to avoid because ML bacteria are often present during phase 1 MOx treatment. We investigated the effect of common yeast and bacteria on the outcome of micro-oxygenation. Compared to sterile filtered wine, Saccharomyces cerevisiae inoculation significantly increased oxygen consumption, keeping dissolved oxygen in wine below 30 µg L -1 during micro-oxygenation, whereas Oenococcus oeni inoculation was not associated with a significant impact on the concentration of dissolved oxygen. The unfiltered baseline wine also had both present, although with much higher populations of bacteria and consumed oxygen. The yeast-treated wine yielded much higher levels of acetaldehyde, rising from 4.3 to 29 mg L -1 during micro-oxygenation, whereas no significant difference was found between the bacteria-treated wine and the filtered control. The unfiltered wine exhibited rapid oxygen consumption but no additional acetaldehyde, as well as reduced pyruvate. Analysis of the acetaldehyde-glycerol acetal levels showed a good correlation with acetaldehyde concentrations. The production of acetaldehyde is a key outcome of MOx and it is dramatically increased in the presence of yeast, although it is possibly counteracted by the metabolism of O. oeni bacteria. Additional controlled experiments are necessary to clarify the interaction of yeast and bacteria during MOx treatments. Analysis of the glycerol acetals may be useful as a proxy for acetaldehyde levels. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Breathing disturbances without hypoxia are associated with objective sleepiness in sleep apnea

DEFF Research Database (Denmark)

Koch, Henriette; Schneider, Logan Douglas; Finn, Laurel A

2017-01-01

analyzed with our automated algorithm, developed to detect breathing disturbances and desaturations. Breathing events were time-locked to desaturations, resulting in 2 indices - desaturating (H-BDI) and non-desaturating (NH-BDI) events - regardless of arousals. Measures of subjective (Epworth Sleepiness...... Scale) and objective (2,981 multiple sleep latency tests from a subset of 865 subjects) sleepiness were analyzed, in addition to clinically relevant clinicodemographic variables. Hypertension was defined as BP ≥140/90 or antihypertensive use. H-BDI, but not NH-BDI, correlated strongly with SDB severity...... indices that included hypoxia (r≥0.89, p≤0.001 with 3% ODI and AHI with 4%-desaturations). A doubling of desaturation-associated events was associated with hypertension prevalence, which was significant for ODI but not H-BDI (3% ODI OR=1.06, 95% CI=1.00-1.12, p...

Oxygen configurations in silica

International Nuclear Information System (INIS)

Chelikowsky, James R.; Chadi, D. J.; Binggeli, N.

2000-01-01

We propose a transition state for oxygen in silica. This state is produced by the insertion of an oxygen molecule into the Si-O-Si bond, i.e., it consists of producing a Si-O-O-O-Si bond. This state allows molecular oxygen diffusion in silica without breaking the molecular O 2 bond and it is energetically more stable than a peroxy configuration. This configuration may allow for exchange of molecular oxygen with the oxygen in the silica framework. (c) 2000 The American Physical Society

Oxygen transport by oxygen potential gradient in dense ceramic oxide membranes

Energy Technology Data Exchange (ETDEWEB)

Maiya, P.S.; Balachandran, U.; Dusek, J.T.; Mieville, R.L. [Argonne National Lab., IL (United States). Energy Technology Div.; Kleefisch, M.S.; Udovich, C.A. [Amoco Exploration/Production, Naperville, IL (United States)

1996-05-01

Numerous studies have been conducted in recent years on the partial oxidation of methane to synthesis gas (syngas: CO + H{sub 2}) with air as the oxidant. In partial oxidation, a mixed-oxide ceramic membrane selectively transports oxygen from the air; this transport is driven by the oxygen potential gradient. Of the several ceramic materials the authors have tested, a mixed oxide based on the Sr-Fe-Co-O system has been found to be very attractive. Extensive oxygen permeability data have been obtained for this material in methane conversion experiments carried out in a reactor. The data have been analyzed by a transport equation based on the phenomenological theory of diffusion under oxygen potential gradients. Thermodynamic calculations were used to estimate the driving force for the transport of oxygen ions. The results show that the transport equation deduced from the literature describes the permeability data reasonably well and can be used to determine the diffusion coefficients and the associated activation energy of oxygen ions in the ceramic membrane material.

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.

Comparison of domiciliary oxygen using liquid oxygen and concentrator in northern Taiwan

Directory of Open Access Journals (Sweden)

Chien-Ling Su

2014-01-01

Conclusion: Patients in the LOG used oxygen for longer hours, went on more outings, and were more likely to travel with oxygen than patients in the OCG. Being ambulatory with liquid oxygen might enable patients with COPD to walk more effectively.

Svær cervikal kyfose som årsag til akut opstået respirationsinsufficiens

DEFF Research Database (Denmark)

Andersen, Karen Lise Dahl; Bach, Allan; Iversen, Rikke Haahr

2017-01-01

Severe cervical kyphosis causing sudden inspiratory stridor An 85-year-old woman was brought to an accident and emergency department with breathing difficulties accompanied by inspiratory stridor. She was being treated for hypertension and severe osteoporosis which had caused thoracal and cervical...... fractures of the columna. Intubation was initiated as she desaturated and deteriorated despite maximum oxygen therapy. The intubation revealed a subglottic stenosis as a consequence of a recent osteoporotic fracture in the cervical columna. This represents a rare cause of respiratory failure as all other...

Simultaneous Monitoring of Vascular Oxygenation and Tissue Oxygen Tension of Breast Tumors Under Hyperbaric Oxygen Exposure

Science.gov (United States)

2008-04-01

28. Alagoz, T., R. Buller, B. Anderson, K. Terrell , R...and oxygenation Ann . New Acad. Sci. 838 29–45 Chapman J D, Stobbe C C, Arnfield M R, Santus R, Lee J and McPhee M S 1991 Oxygen dependency of tumor

Coronary flow reserve index corrected by exercise load using Tl-201 SPECT

International Nuclear Information System (INIS)

Kubota, Yasushi; Sugihara, Hiroki; Azuma, Akihiro

1990-01-01

For simple, non-invasive evaluation of coronary flow reserve during exercise, we investigated the coronary flow reserve index using the ratio of change of fractional distribution in the regional myocardium to oxygen demand. The subjects included 24 patients with effort angina pectoris and 11 normal volunteers. PTCA was peformed for 11 patients. Using the biological properties of Tl-201 single photon emission computed tomography (SPECT) was performed at submaximal exercise and at rest by two successive injections of Tl-201 within a short time interval (double dose method). The correlation between the fractional distribution in the myocardium (Δ-Fract) and the oxygen demand during exercise and at rest were evaluated. Δ-Fract correlated well with the rate of change of the pressure rate product (Δ-PRP), and Δ-Fract/Δ-PRP (CRI) was a good indicator of the coronary flow reserve index. CRI in the ischemic region correlated well with the percent area stenosis of the supplying coronary artery and improved with resolution of percent area stenosis of the target coronary artery after PTCA, but in some cases they were not above the normal range. CRI as obtained by exercise SPECT using the double dose method is useful for non-invasively estimating the coronary flow reserve during exercise, and it can be used for evaluating the effect before and after PTCA. (author)

Recombination and detachment in oxygen discharges: the role of metastable oxygen molecules

International Nuclear Information System (INIS)

Gudmundsson, J T

2004-01-01

A global (volume averaged) model of oxygen discharges is used to study the transition from a recombination dominated discharge to a detachment dominated discharge. The model includes the metastable oxygen molecules O 2 (a 1 Δ g ) and O 2 (b 1 Σ g + ) and the three Herzberg states O 2 (A 3 Σ u + , A' 3 Δ u , c 1 Σ u - ). Dissociative attachment of the oxygen molecule in the ground state O 2 ( 3 Σ g - ) and the metastable oxygen molecule O 2 (a 1 Δ g ) are the dominating channels for creation of the negative oxygen ion O - . At high pressures, dissociative attachment of the Herzberg states contributes significantly to the creation of the negative oxygen ion, O - . The detachment by a collision of the metastable oxygen molecule O 2 (b 1 Σ g + ) with the oxygen ion, O - , is a significant loss process for the O - at pressures above 10 mTorr. Its contribution to the loss is more significant at a lower applied power, but at the higher pressures it is always significant. Detachment by collision with O( 3 P) is also an important loss mechanism for O - . We find that ion-ion recombination is the dominating loss process for negative ions in oxygen discharges at low pressures and calculate the critical pressure where the contributions of recombination reactions and detachment reactions are equal. This critical pressure depends on the applied power, increases with applied power and is in the range 5-14 mTorr in the pressure and power range investigated

Effect of hypolimnetic oxygenation on oxygen depletion rates in two water-supply reservoirs.

Science.gov (United States)

Gantzer, Paul A; Bryant, Lee D; Little, John C

2009-04-01

Oxygenation systems, such as bubble-plume diffusers, are used to improve water quality by replenishing dissolved oxygen (DO) in the hypolimnia of water-supply reservoirs. The diffusers induce circulation and mixing, which helps distribute DO throughout the hypolimnion. Mixing, however, has also been observed to increase hypolimnetic oxygen demand (HOD) during system operation, thus accelerating oxygen depletion. Two water-supply reservoirs (Spring Hollow Reservoir (SHR) and Carvins Cove Reservoir (CCR)) that employ linear bubble-plume diffusers were studied to quantify diffuser effects on HOD. A recently validated plume model was used to predict oxygen addition rates. The results were used together with observed oxygen accumulation rates to evaluate HOD over a wide range of applied gas flow rates. Plume-induced mixing correlated well with applied gas flow rate and was observed to increase HOD. Linear relationships between applied gas flow rate and HOD were found for both SHR and CCR. HOD was also observed to be independent of bulk hypolimnion oxygen concentration, indicating that HOD is controlled by induced mixing. Despite transient increases in HOD, oxygenation caused an overall decrease in background HOD, as well as a decrease in induced HOD during diffuser operation, over several years. This suggests that the residual or background oxygen demand decreases from one year to the next. Despite diffuser-induced increases in HOD, hypolimnetic oxygenation remains a viable method for replenishing DO in thermally-stratified water-supply reservoirs such as SHR and CCR.

Spray generator of singlet oxygen for a chemical oxygen-iodine laser

Czech Academy of Sciences Publication Activity Database

Jirásek, Vít; Hrubý, Jan; Špalek, Otomar; Čenský, Miroslav; Kodymová, Jarmila

2010-01-01

Roč. 100, č. 4 (2010), s. 779-791 ISSN 0946-2171 Grant - others:European Office of Aerospace R&D(US) FA8655-09-1-3091 Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z20760514 Keywords : spray generator of singlet oxygen * singlet oxygen * chemical oxygen-iodine laser Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.239, year: 2010

Effects of the oxygenation level on formation of different reactive oxygen species during photodynamic therapy.

Science.gov (United States)

Price, Michael; Heilbrun, Lance; Kessel, David

2013-01-01

We examined the effect of the oxygenation level on efficacy of two photosensitizing agents, both of which target lysosomes for photodamage, but via different photochemical pathways. Upon irradiation, the chlorin termed NPe6 forms singlet oxygen in high yield while the bacteriopheophorbide WST11 forms only oxygen radicals (in an aqueous environment). Photokilling efficacy by WST11 in cell culture was impaired when the atmospheric oxygen concentration was reduced from 20% to 1%, while photokilling by NPe6 was unaffected. Studies in a cell-free system revealed that the rates of photobleaching of these agents, as a function of the oxygenation level, were correlated with results described above. Moreover, the rate of formation of oxygen radicals by either agent was more sensitive to the level of oxygenation than was singlet oxygen formation by NPe6. These data indicate that the photochemical process that leads to oxygen radical formation is more dependent on the oxygenation level than is the pathway leading to formation of singlet oxygen. © 2013 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2013 The American Society of Photobiology.

Correlation between sleep apnea syndrome and heart failure depending on ejection fraction

Directory of Open Access Journals (Sweden)

Carmen Loredana Ardelean

2016-12-01

Full Text Available OBJECTIVES The aim of this study was to analyze the correlations between sleep apnea syndrome(SAS and heart failure(HF in patients with preserved or reduced ejection fraction(EF. MATERIALS AND METHODS We evaluated 51 patients with suspected SAS and HF in sleep lab in Timișoara. General data was collected using sleep questionnaires, anthropometric measurements, somnography for apnea-hypopnea index, oxygen desaturation index, echocardiographic data, comorbidities and lab tests. RESULTS Creatinine -1.1±0.2 vs 1.4±0.7, p=0.05; stroke-23% vs 4%, p=0.04; aortic insufficiency-11.5% vs 36%, p=0.04; tricuspid insufficiency-46.1% vs 80%, p=0.01. Differences between groups regarding anthropometric measurements, somnographic index, lipidic profile were not statistically significant.. CONCLUSIONS Patients with SAS-IC with preserved EF have a higher risk of stroke events. Patients with IC with EF<50% had a significantly increased risk of developing a life-long chronic kidney disease. The SAS-IC population with low EF is at a higher risk of developing aortic and tricuspid insufficiency. REFERENCES 1. Douglas T. Sleep Apnea and Heart Failure. Part1: Obstructive Sleep Apnea. Circulation.2003.107:1671-1678. 2. Takatoshi K, Douglas TB. Obstructive Sleep Apnea and Heart Failure-Pathophysiologic and Therapeutic Implication. Journal of the American College of Cardiology. 2011; 57:doi: 10.1016/j.jacc.2010.08.627 3. Ferrier K, Campbell A, Yee B et al. Sleepdisordered breathing occurs frequently in stable outpatients with congestive heart failure. Chest. 2005;128:2116–2122.

Advanced Oxygen Systems for Aircraft (Systemes d’Oxygene Avances)

Science.gov (United States)

1996-04-01

Oxygen Generating System (NAOGS), SAM-TR-80-12, Brooks AFB TX 78235, 1980. 11. Horch TC, Miller RL, Bomar JB, Tedor JB, Holden RD, Ikels KG, and...sieve oxygen generation sys- tem. Data from Horch et al (15). cabin altitude. The minimum and maximum oxygen concen- tration lines depict the...an AV-8A Aircraft; Naval Air Test Center Report No. SY-136R-81, 1981. 15. Horch TC, Miller RL, Bomar JB Jr, Tedor JB, Holden RD, Ikels KG, and

Kinetics of oxygen species in an electrically driven singlet oxygen generator

Science.gov (United States)

Azyazov, V. N.; Torbin, A. P.; Pershin, A. A.; Mikheyev, P. A.; Heaven, M. C.

2015-12-01

The kinetics of oxygen species in the gaseous medium of a discharge singlet oxygen generator has been revisited. Vibrationally excited ozone O3(υ) formed in O + O2 recombination is thought to be a significant agent in the deactivation of singlet oxygen O2(a1Δ), oxygen atom removal and ozone formation. It is shown that the process O3(υ ⩾ 2) + O2(a1Δ) → 2O2 + O is the main O2(a1Δ) deactivation channel in the post-discharge zone. If no measures are taken to decrease the oxygen atom concentration, the contribution of this process to the overall O2(a1Δ) removal is significant, even in the discharge zone. A simplified model for the kinetics of vibrationally excited ozone is proposed. Calculations based on this model yield results that are in good agreement with the experimental data.

Oxygen therapy reduces postoperative tachycardia

DEFF Research Database (Denmark)

Stausholm, K; Kehlet, H; Rosenberg, J

1995-01-01

Concomitant hypoxaemia and tachycardia in the postoperative period is unfavourable for the myocardium. Since hypoxaemia per se may be involved in the pathogenesis of postoperative tachycardia, we have studied the effect of oxygen therapy on tachycardia in 12 patients randomly allocated to blinded...... air or oxygen by facemask on the second or third day after major surgery. Inclusion criteria were arterial hypoxaemia (oxygen saturation 90 beat.min-1). Each patient responded similarly to oxygen therapy: an increase in arterial oxygen saturation and a decrease...... in heart rate (p oxygen has a positive effect on the cardiac oxygen delivery and demand balance....

Dependence of nitrite oxidation on nitrite and oxygen in low-oxygen seawater

Science.gov (United States)

Sun, Xin; Ji, Qixing; Jayakumar, Amal; Ward, Bess B.

2017-08-01

Nitrite oxidation is an essential step in transformations of fixed nitrogen. The physiology of nitrite oxidizing bacteria (NOB) implies that the rates of nitrite oxidation should be controlled by concentration of their substrate, nitrite, and the terminal electron acceptor, oxygen. The sensitivities of nitrite oxidation to oxygen and nitrite concentrations were investigated using 15N tracer incubations in the Eastern Tropical North Pacific. Nitrite stimulated nitrite oxidation under low in situ nitrite conditions, following Michaelis-Menten kinetics, indicating that nitrite was the limiting substrate. The nitrite half-saturation constant (Ks = 0.254 ± 0.161 μM) was 1-3 orders of magnitude lower than in cultivated NOB, indicating higher affinity of marine NOB for nitrite. The highest rates of nitrite oxidation were measured in the oxygen depleted zone (ODZ), and were partially inhibited by additions of oxygen. This oxygen sensitivity suggests that ODZ specialist NOB, adapted to low-oxygen conditions, are responsible for apparently anaerobic nitrite oxidation.

The effect of Sub-maximal exercise-rehabilitation program on cardio-respiratory endurance indexes and oxygen pulse in patients with spastic cerebral palsy

Directory of Open Access Journals (Sweden)

M Izadi

2006-05-01

Full Text Available Background: Physical or cardio-respiratory fitness are of the best important physiological variables in children with cerebral palsy (CP, but the researches on exercise response of individuals with CP are limited. Our aim was to determine the effect of sub-maximal rehabilitation program (aerobic exercise on maximal oxygen uptake, oxygen pulse and cardio- respiratory physiological variables of children with moderate to severe spastic cerebral palsy diplegia and compare with able-bodied children. Methods: In a controlled clinical trial study, 15 children with diplegia spastic cerebral palsy, were recruited on a voluntarily basis (experimental group and 18 subjects without neurological impairments selected as control group. In CP group, aerobic exercise program performed on the average of exercise intensity (144 beat per minute of heart rate, 3 times a week for 3 months. The time of each exercise session was 20-25 minutes. Dependent variables were measured in before (pretest and after (post test of rehabilitation program through Mac Master Protocol on Tantories cycle ergometer in CP group and compared with the control group. Results: The oxygen pulse (VO2/HR during ergometery protocol was significantly lower in CP group than normal group (P<0.05. No significant statistical difference in maximal oxygen uptake (VO2 max was found between groups. The rehabilitation program leads to little increase of this variable in CP group. After sub-maximal exercise in pretest and post test, the heart rate of patient group was greater than control group, and aerobic exercise leads to significant decrease in heart rate in CP patients(P<0.05. Conclusion: The patients with spastic cerebral palsy, because of high muscle tone, severe spasticity and involuntarily movements have higher energy cost and lower aerobic fitness than normal people. The rehabilitation exercise program can improve physiological function of muscle and cardio-respiratory endurance in these

Oxygen transfer rate during the production of alginate by Azotobacter vinelandii under oxygen-limited and non oxygen-limited conditions

Directory of Open Access Journals (Sweden)

Peña Carlos F

2011-02-01

Full Text Available Abstract Background The oxygen transfer rate (OTR and dissolved oxygen tension (DOT play an important role in determining alginate production and its composition; however, no systematic study has been reported about the independent influence of the OTR and DOT. In this paper, we report a study about alginate production and the evolution of the molecular mass of the polymer produced by a wild-type A. vinelandii strain ATCC 9046, in terms of the maximum oxygen transfer rate (OTRmax in cultures where the dissolved oxygen tension (DOT was kept constant. Results The results revealed that in the two dissolved oxygen conditions evaluated, strictly controlled by gas blending at 0.5 and 5% DOT, an increase in the agitation rate (from 300 to 700 rpm caused a significant increase in the OTRmax (from 17 to 100 mmol L-1 h-1 for DOT of 5% and from 6 to 70 mmol L-1 h-1 for DOT of 0.5%. This increase in the OTRmax improved alginate production, as well as the specific alginate production rate (SAPR, reaching a maximal alginate concentration of 3.1 g L-1 and a SAPR of 0.031 g alg g biom-1 h-1 in the cultures at OTRmax of 100 mmol L-1 h-1. In contrast, the mean molecular mass (MMM of the alginate isolated from cultures developed under non-oxygen limited conditions increased by decreasing the OTRmax, reaching a maximal of 550 kDa at an OTRmax of 17 mmol L-1 h-1 . However, in the cultures developed under oxygen limitation (0.5% DOT, the MMM of the polymer was practically the same (around 200 kDa at 300 and 700 rpm, and this remained constant throughout the cultivation. Conclusions Overall, our results showed that under oxygen-limited and non oxygen-limited conditions, alginate production and its molecular mass are linked to the OTRmax, independently of the DOT of the culture.

A new device for administration of continuous positive airway pressure in preterm infants: comparison with a standard nasal CPAP continuous positive airway pressure system.

Science.gov (United States)

Trevisanuto, Daniele; Grazzina, Nicoletta; Doglioni, Nicoletta; Ferrarese, Paola; Marzari, Francesco; Zanardo, Vincenzo

2005-06-01

We compared the effectiveness of a new continuous positive airway pressure (CPAP) device (neonatal helmet CPAP) with a conventional nasal CPAP system in preterm neonates needing continuous distending pressure. Randomized, physiological, cross-over study in a tertiary referral, neonatal intensive care unit in a university teaching hospital. Twenty very low birth weight infants with a postnatal age greater than 24 h who were receiving nasal CPAP for apnea and/or mild respiratory distress were enrolled. CPAP delivered by neonatal helmet CPAP and nasal CPAP in random order for two subsequent 90-min periods. Were continuously measured the Neonatal Infant Pain Scale (NIPS) score, oxygen requirements, respiratory rate, heart rate, oxygen saturation, transcutaneous PO(2) (tcPO(2)) and PCO(2) (tcPCO(2)), blood pressure, and desaturations. NIPS scores were significantly lower when the infants were on the neonatal helmet CPAP than when they were on nasal CPAP (0.26+/-0.07 vs. 0.63+/-0.12). The other studied parameters did not differ between the two CPAP modes. The number of desaturations was reduced during the neonatal helmet CPAP treatment (18 vs. 32), although this difference was not significant. In this short-term physiological study the neonatal helmet CPAP appears to be as good as the golden standard for managing preterm infants needing continuous distending pressure, with enhanced tolerability. Further evaluation in a randomized clinical trial is needed to confirm these findings.

Characterization of fluorinated silica thin films with ultra-low refractive index deposited at low temperature

Energy Technology Data Exchange (ETDEWEB)

Abbasi-Firouzjah, Marzieh [Semnan Science and Technology Park, 3614933578, Shahrood (Iran, Islamic Republic of); Shokri, Babak, E-mail: b-shokri@sbu.ac.ir [Laser & Plasma Research Institute, Shahid Beheshti University, G.C., Evin, Tehran 1983963113 (Iran, Islamic Republic of); Physics Department, Shahid Beheshti University, G.C., Evin, Tehran 1983963113 (Iran, Islamic Republic of)

2015-02-27

Structural and optical properties of low refractive index fluorinated silica (SiO{sub x}C{sub y}F{sub z}) films were investigated. The films were deposited on p-type silicon and polycarbonate substrates by radio frequency plasma enhanced chemical vapor deposition method at low temperatures. A mixture of tetraethoxysilane vapor, oxygen, and CF{sub 4} was used for deposition of the films. The influence of oxygen flow rate on the elemental compositions, chemical bonding states and surface roughness of the films was studied using energy dispersive X-ray analyzer, Fourier transform infrared spectroscopy in reflectance mode and atomic force microscopy, respectively. Effects of chemical bonds of the film matrix on optical properties and chemical stability were discussed. Energy dispersive spectroscopy showed high fluorine content in the SiO{sub x}C{sub y}F{sub z} film matrix which is in the range of 7.6–11.3%. It was concluded that in fluorine content lower than a certain limit, chemical stability of the film enhances, while higher contents of fluorine heighten moisture absorption followed by increasing refractive index. All of the deposited films were highly transparent. Finally, it was found that the refractive index of the SiO{sub x}C{sub y}F{sub z} film was continuously decreased with the increase of the O{sub 2} flow rate down to the minimum value of 1.16 ± 0.01 (at 632.8 nm) having the most ordered and nano-void structure and the least organic impurities. This sample also had the most chemical stability against moisture absorption. - Highlights: • Low deposition temperature and organic precursor led to higher film fluorination. • High fluorine and nanovoid structure led to drastic decrease in the refractive index. • Silica based thin film with ultralow refractive index of 1.16 was produced. • The produced ultralow-n film is highly stable against moisture absorption.

Oxygen Partial Pressure Is a Rate-Limiting Parameter for Cell Proliferation in 3D Spheroids Grown in Physioxic Culture Condition.

Science.gov (United States)

Gomes, Aurélie; Guillaume, Ludivine; Grimes, David Robert; Fehrenbach, Jérôme; Lobjois, Valérie; Ducommun, Bernard

2016-01-01

The in situ oxygen partial pressure in normal and tumor tissues is in the range of a few percent. Therefore, when studying cell growth in 3D culture systems, it is essential to consider how the physiological oxygen concentration, rather than the one in the ambient air, influences the proliferation parameters. Here, we investigated the effect of reducing oxygen partial pressure from 21% to 5% on cell proliferation rate and regionalization in a 3D tumor spheroid model. We found that 5% oxygen concentration strongly inhibited spheroid growth, changed the proliferation gradient and reduced the 50% In Depth Proliferation index (IDP50), compared with culture at 21% oxygen. We then modeled the oxygen partial pressure profiles using the experimental data generated by culturing spheroids in physioxic and normoxic conditions. Although hypoxia occurred at similar depth in spheroids grown in the two conditions, oxygen partial pressure was a major rate-limiting factor with a critical effect on cell proliferation rate and regionalization only in spheroids grown in physioxic condition and not in spheroids grown at atmospheric normoxia. Our findings strengthen the need to consider conducting experiment in physioxic conditions (i.e., tissue normoxia) for proper understanding of cancer cell biology and the evaluation of anticancer drugs in 3D culture systems.

A theoretical model for oxygen transport in skeletal muscle under conditions of high oxygen demand.

Science.gov (United States)

McGuire, B J; Secomb, T W

2001-11-01

Oxygen transport from capillaries to exercising skeletal muscle is studied by use of a Krogh-type cylinder model. The goal is to predict oxygen consumption under conditions of high demand, on the basis of a consideration of transport processes occurring at the microvascular level. Effects of the decline in oxygen content of blood flowing along capillaries, intravascular resistance to oxygen diffusion, and myoglobin-facilitated diffusion are included. Parameter values are based on human skeletal muscle. The dependence of oxygen consumption on oxygen demand, perfusion, and capillary density are examined. When demand is moderate, the tissue is well oxygenated and consumption is slightly less than demand. When demand is high, capillary oxygen content declines rapidly with axial distance and radial oxygen transport is limited by diffusion resistance within the capillary and the tissue. Under these conditions, much of the tissue is hypoxic, consumption is substantially less than demand, and consumption is strongly dependent on capillary density. Predicted consumption rates are comparable with experimentally observed maximal rates of oxygen consumption.

Oxygen-transfer performance of a newly designed, very low-volume membrane oxygenator.

Science.gov (United States)

Burn, Felice; Ciocan, Sorin; Carmona, Natalia Mendez; Berner, Marion; Sourdon, Joevin; Carrel, Thierry P; Tevaearai Stahel, Hendrik T; Longnus, Sarah L

2015-09-01

Oxygenation of blood and other physiological solutions are routinely required in fundamental research for both in vitro and in vivo experimentation. However, very few oxygenators with suitable priming volumes (parallel-oriented microporous polypropylene hollow fibres, placed inside a hollow shell with a lateral-luer outlet, and sealed at both extremities. With this design, perfusate is delivered via the core-tube to the centre of the mini-oxygenator, and exits via the luer port. A series of mini-oxygenators were constructed and tested in an in vitro perfusion circuit by monitoring oxygen transfer using modified Krebs-Henseleit buffer or whole porcine blood. Effects of perfusion pressure and temperature over flows of 5-60 ml × min(-1) were assessed. Twelve mini-oxygenators with a mean priming volume of 1.5 ± 0.3 ml were evaluated. With buffer, oxygen transfer reached a maximum of 14.8 ± 1.0 ml O2 × l(-1) (pO2: 450 ± 32 mmHg) at perfusate flow rates of 5 ml × min(-1) and decreased with an increase in perfusate flow to 7.8 ± 0.7 ml ml O2 × l(-1) (pO2: 219 ± 24 mmHg) at 60 ml × min(-1). Similarly, with blood perfusate, oxygen transfer also decreased as perfusate flow increased, ranging from 33 ± 5 ml O2 × l(-1) at 5 ml × min(-1) to 11 ± 2 ml O2 × l(-1) at 60 ml × min(-1). Furthermore, oxygen transfer capacity remained stable with blood perfusion over a period of at least 2 h. We have developed a new miniaturized membrane oxygenator with an ultra-low priming volume (circuits, such as small animal extracorporeal circulation and ex vivo organ perfusion. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

High-precision diode-laser-based temperature measurement for air refractive index compensation.

Science.gov (United States)

Hieta, Tuomas; Merimaa, Mikko; Vainio, Markku; Seppä, Jeremias; Lassila, Antti

2011-11-01

We present a laser-based system to measure the refractive index of air over a long path length. In optical distance measurements, it is essential to know the refractive index of air with high accuracy. Commonly, the refractive index of air is calculated from the properties of the ambient air using either Ciddor or Edlén equations, where the dominant uncertainty component is in most cases the air temperature. The method developed in this work utilizes direct absorption spectroscopy of oxygen to measure the average temperature of air and of water vapor to measure relative humidity. The method allows measurement of temperature and humidity over the same beam path as in optical distance measurement, providing spatially well-matching data. Indoor and outdoor measurements demonstrate the effectiveness of the method. In particular, we demonstrate an effective compensation of the refractive index of air in an interferometric length measurement at a time-variant and spatially nonhomogeneous temperature over a long time period. Further, we were able to demonstrate 7 mK RMS noise over a 67 m path length using a 120 s sample time. To our knowledge, this is the best temperature precision reported for a spectroscopic temperature measurement. © 2011 Optical Society of America

Carbon mineralization and oxygen dynamics in sediments with deep oxygen penetration, Lake Superior

DEFF Research Database (Denmark)

Li, Jiying; Crowe, Sean Andrew; Miklesh, David

2012-01-01

To understand carbon and oxygen dynamics in sediments with deep oxygen penetration, we investigated eight locations (160–318-m depth) throughout Lake Superior. Despite the 2–4 weight percent organic carbon content, oxygen penetrated into the sediment by 3.5 to > 12 cm at all locations. Such deep ...... volume-specific carbon degradation rates were 0.3–1.5 µmol cm−3 d−1; bioturbation coefficient near the sediment surface was 3–8 cm2 yr−1. These results indicate that carbon cycling in large freshwater systems conforms to many of the same trends as in marine systems.......To understand carbon and oxygen dynamics in sediments with deep oxygen penetration, we investigated eight locations (160–318-m depth) throughout Lake Superior. Despite the 2–4 weight percent organic carbon content, oxygen penetrated into the sediment by 3.5 to > 12 cm at all locations. Such deep......, suggesting that temporal variability in deeply oxygenated sediments may be greater than previously acknowledged. The oxygen uptake rates (4.4–7.7 mmol m−2 d−1, average 6.1 mmol m−2 d−1) and carbon mineralization efficiency (∼ 90% of deposited carbon) were similar to those in marine hemipelagic and pelagic...

Spatially monitoring oxygen level in 3D microfabricated cell culture systems using optical oxygen sensing beads.

Science.gov (United States)

Wang, Lin; Acosta, Miguel A; Leach, Jennie B; Carrier, Rebecca L

2013-04-21

Capability of measuring and monitoring local oxygen concentration at the single cell level (tens of microns scale) is often desirable but difficult to achieve in cell culture. In this study, biocompatible oxygen sensing beads were prepared and tested for their potential for real-time monitoring and mapping of local oxygen concentration in 3D micro-patterned cell culture systems. Each oxygen sensing bead is composed of a silica core loaded with both an oxygen sensitive Ru(Ph2phen3)Cl2 dye and oxygen insensitive Nile blue reference dye, and a poly-dimethylsiloxane (PDMS) shell rendering biocompatibility. Human intestinal epithelial Caco-2 cells were cultivated on a series of PDMS and type I collagen based substrates patterned with micro-well arrays for 3 or 7 days, and then brought into contact with oxygen sensing beads. Using an image analysis algorithm to convert florescence intensity of beads to partial oxygen pressure in the culture system, tens of microns-size oxygen sensing beads enabled the spatial measurement of local oxygen concentration in the microfabricated system. Results generally indicated lower oxygen level inside wells than on top of wells, and local oxygen level dependence on structural features of cell culture surfaces. Interestingly, chemical composition of cell culture substrates also appeared to affect oxygen level, with type-I collagen based cell culture systems having lower oxygen concentration compared to PDMS based cell culture systems. In general, results suggest that oxygen sensing beads can be utilized to achieve real-time and local monitoring of micro-environment oxygen level in 3D microfabricated cell culture systems.

Oxygen evolution reaction catalysis

Energy Technology Data Exchange (ETDEWEB)

Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

2016-09-06

An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

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.

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.

Massive Cerebral Gas Embolism under Discectomy due to Hydrogen Peroxide Irrigation

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Junjie Zhang

2015-01-01

Full Text Available Massive cerebral and spinal gas embolism occurs rarely as a complication of discectomy. We report a 54-year-old female who had undergone a discectomy (L3/4 and L4/5 under epidural anesthesia in a local hospital developed multiple massive gas embolisms. At closure, surgeons irrigated the incision wound with hydrogen peroxide. Soon after the irrigation, the patient suddenly developed tachycardia, hypotension, and rapid oxygen desaturation. Subsequently, patient progressed into unconsciousness and right hemianopsia quadriplegia. Computed tomography (CT scan showed multiple hypointensity spots around the brain due to cerebral gas embolism, which indicated the pneumoencephalos. The likely mechanism was the absorption of hydrogen peroxide into blood. When the amount of oxygen evolved exceeded its maximal blood solubility, venous embolization occurred. Though the patient was treated with supportive treatments and hyperbaric oxygen, she did not get full recovery and was left with severe long-term cerebral injury.

Sequential Oxygenation Index and Organ Dysfunction Assessment within the First 3 Days of Mechanical Ventilation Predict the Outcome of Adult Patients with Severe Acute Respiratory Failure

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Hsu-Ching Kao

2013-01-01

Full Text Available Objective. To determine early predictors of outcomes of adult patients with severe acute respiratory failure. Method. 100 consecutive adult patients with severe acute respiratory failure were evaluated in this retrospective study. Data including comorbidities, Sequential Organ Failure Assessment (SOFA score, Acute Physiological Assessment and Chronic Health Evaluation II (APACHE II score, PaO2, FiO2, PaO2/FiO2, PEEP, mean airway pressure (mPaw, and oxygenation index (OI on the 1st and the 3rd day of mechanical ventilation, and change in OI within 3 days were recorded. Primary outcome was hospital mortality; secondary outcome measure was ventilator weaning failure. Results. 38 out of 100 (38% patients died within the study period. 48 patients (48% failed to wean from ventilator. Multivariate analysis showed day 3 OI ( and SOFA ( score were independent predictors of hospital mortality. Preexisting cerebrovascular accident (CVA ( was the predictor of weaning failure. Results from Kaplan-Meier method demonstrated that higher day 3 OI was associated with shorter survival time (log-Rank test, . Conclusion. Early OI (within 3 days and SOFA score were predictors of mortality in severe acute respiratory failure. In the future, prospective studies measuring serial OIs in a larger scale of study cohort is required to further consolidate our findings.

Integrated turbomachine oxygen plant

Science.gov (United States)

Anand, Ashok Kumar; DePuy, Richard Anthony; Muthaiah, Veerappan

2014-06-17

An integrated turbomachine oxygen plant includes a turbomachine and an air separation unit. One or more compressor pathways flow compressed air from a compressor through one or more of a combustor and a turbine expander to cool the combustor and/or the turbine expander. An air separation unit is operably connected to the one or more compressor pathways and is configured to separate the compressed air into oxygen and oxygen-depleted air. A method of air separation in an integrated turbomachine oxygen plant includes compressing a flow of air in a compressor of a turbomachine. The compressed flow of air is flowed through one or more of a combustor and a turbine expander of the turbomachine to cool the combustor and/or the turbine expander. The compressed flow of air is directed to an air separation unit and is separated into oxygen and oxygen-depleted air.

Oxygen sensitive polymeric nanocapsules for optical dissolved oxygen sensors

Science.gov (United States)

Sun, Zhijuan; Cai, Chenxin; Guo, Fei; Ye, Changhuai; Luo, Yingwu; Ye, Shuming; Luo, Jianchao; Zhu, Fan; Jiang, Chunyue

2018-04-01

Immobilization of the oxygen-sensitive probes (OSPs) in the host matrix greatly impacts the performance and long-term usage of the optical dissolved oxygen (DO) sensors. In this work, fluorescent dyes, as the OSPs, were encapsulated with a crosslinked fluorinated polymer shell by interfacial confined reversible addition fragmentation chain transfer miniemulsion polymerization to fabricate oxygen sensitive polymeric nanocapsules (NCs). The location of fluorescent dyes and the fluorescent properties of the NCs were fully characterized by fourier transform infrared spectrometer, x-ray photoelectron spectrometer and fluorescent spectrum. Dye-encapsulated capacity can be precisely tuned from 0 to 1.3 wt% without self-quenching of the fluorescent dye. The crosslinked fluorinated polymer shell is not only extremely high gas permeability, but also prevents the fluorescent dyes from leakage in aqueous as well as in various organic solvents, such as ethanol, acetone and tetrahydrofuran (THF). An optical DO sensor based on the oxygen sensitive NCs was fabricated, showing high sensitivity, short response time, full reversibility, and long-term operational stability of online monitoring DO. The sensitivity of the optical DO sensor is 7.02 (the ratio of the response value in fully deoxygenated and saturated oxygenated water) in the range 0.96-14.16 mg l-1 and the response time is about 14.3 s. The sensor’s work curve was fit well using the modified Stern-Volmer equation by two-site model, and its response values are hardly affected by pH ranging from 2 to 12 and keep constant during continuous measurement for 3 months. It is believed that the oxygen sensitive polymeric NCs-based optical DO sensor could be particularly useful in long-term online DO monitoring in both aqueous and organic solvent systems.

Sleep Disordered Breathing During Live High-Train Low in Normobaric Versus Hypobaric Hypoxia.

Science.gov (United States)

Saugy, Jonas J; Schmitt, Laurent; Fallet, Sibylle; Faiss, Raphael; Vesin, Jean-Marc; Bertschi, Mattia; Heinzer, Raphaël; Millet, Grégoire P

2016-09-01

Saugy, Jonas J., Laurent Schmitt, Sibylle Fallet, Raphael Faiss, Jean-Marc Vesin, Mattia Bertschi, Raphaël Heinzer, and Grégoire P. Millet. Sleep disordered breathing during live high-train low in normobaric versus hypobaric hypoxia. High Alt Med Biol. 17:233-238, 2016.-The present study aimed to compare sleep disordered breathing during live high-train low (LHTL) altitude camp using normobaric hypoxia (NH) and hypobaric hypoxia (HH). Sixteen highly trained triathletes completed two 18-day LHTL camps in a crossover designed study. They trained at 1100-1200 m while they slept either in NH at a simulated altitude of 2250 m or in HH. Breathing frequency and oxygen saturation (SpO 2 ) were recorded continuously during all nights and oxygen desaturation index (ODI 3%) calculated. Breathing frequency was lower for NH than HH during the camps (14.6 ± 3.1 breath × min -1 vs. 17.2 ± 3.4 breath × min -1 , p < 0.001). SpO 2 was lower for HH than NH (90.8 ± 0.3 vs. 91.9 ± 0.2, p < 0.001) and ODI 3% was higher for HH than NH (15.1 ± 3.5 vs. 9.9 ± 1.6, p < 0.001). Sleep in moderate HH is more altered than in NH during a LHTL camp.

Lack of effect of sleep apnea on oxidative stress in obstructive sleep apnea syndrome (OSAS patients.

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M Simiakakis

Full Text Available PURPOSE: The aim of this study was to evaluate markers of systemic oxidative stress and antioxidant capacity in subjects with and without OSAS in order to investigate the most important factors that determine the oxidant-antioxidant status. METHODS: A total of 66 subjects referred to our Sleep laboratory were examined by full polysomnography. Oxidative stress and antioxidant activity were assessed by measurement of the derivatives of reactive oxygen metabolites (d-ROMs and the biological antioxidant capacity (BAP in blood samples taken in the morning after the sleep study. Known risk factors for oxidative stress, such as age, sex, obesity, smoking, hypelipidemia, and hypertension, were investigated as possible confounding factors. RESULTS: 42 patients with OSAS (Apnea-Hypopnea index >15 events/hour were compared with 24 controls (AHI<5. The levels of d-ROMS were significantly higher (p = 0.005 in the control group but the levels of antioxidant capacity were significantly lower (p = 0.004 in OSAS patients. The most important factors predicting the variance of oxidative stress were obesity, smoking habit, and sex. Parameters of sleep apnea severity were not associated with oxidative stress. Minimal oxygen desaturation and smoking habit were the most important predicting factors of BAP levels. CONCLUSION: Obesity, smoking, and sex are the most important determinants of oxidative stress in OSAS subjects. Sleep apnea might enhance oxidative stress by the reduction of antioxidant capacity of blood due to nocturnal hypoxia.

Clinical and echocardiographic characteristics associated with the evolution of the ductus arteriosus in the neonate with birth weight lower than 1,500g.

Science.gov (United States)

Visconti, Luiza Fortunato; Morhy, Samira Saady; Deutsch, Alice D'Agostini; Tavares, Gláucia Maria Penha; Wilberg, Tatiana Jardim Mussi; Rossi, Felipe de Souza

2013-01-01

To identify clinical and echocardiographic parameters associated with the evolution of the ductus arteriosus in neonates with birth weight lower than 1,500g. Retrospective study of 119 neonates in which clinical parameters (Prenatal: maternal age, risk of infection and chorioamnionitis, use of corticosteroid, mode of delivery and gestational age. Perinatal: weight, Apgar score, gender and birth weight/gestational age classification; Postnatal: use of surfactant, sepsis, fluid intake, heart murmur, heart rate, precordial movement and pulses, use of diuretics, oxygenation index, desaturation/apnea, ventilatory support, food intolerance, chest radiography, renal function, hemodynamic instability, and metabolic changes) and echocardiographic parameters (ductus arteriosus diameter, ductus arteriosus/weight ratio, left atrium/ aorta ratio, left ventricular diastolic diameter, and transductal flow direction, pattern and velocity) were analyzed. The clinical and echocardiographic parameters analyzed were considered statistically significant when ppatent ductus arteriosus was 61.3%; 56 received treatment (46 pharmacological and 10 surgical treatment), 11 had spontaneous closure, 4 died, and 2 were discharged with patent ductus arteriosus. A higher incidence of chorioamnionitis, use of surfactant, lower weight and gestational age, sepsis, heart murmur, ventilatory support and worse oxygenation indices were observed in the neonates receiving treatment. The group with spontaneous closure had a smaller ductus arteriosus diameter, lower ductus arteriosus/weight ratio, and higher transductal flow velocity. Based on clinical and echocardiographic parameters, the neonates with spontaneous closure of the ductus arteriosus could be differentiated from those who required treatment.

Muscle oxygenation and fascicle length during passive muscle stretching in ballet-trained subjects.

Science.gov (United States)

Otsuki, A; Fujita, E; Ikegawa, S; Kuno-Mizumura, M

2011-07-01

Muscle stretching transiently decreases muscle-blood flow corresponding to a muscle extension. It may disturb a balance between muscular oxygen demand and oxygen supply to muscles and reduce muscle oxygenation. However, muscle-stretching training may improve blood circulatory condition, resulting in the maintained muscle oxygenation during muscle stretching. The aim of this study was to investigate changes in muscle-blood volume (tHb) and tissue oxygenation index (TOI) during muscle stretching determined by using near-infrared spectroscopy (NIRS) in ballet-trained (BT) and untrained (C) subjects. 11 BT women who regularly perform muscle stretching and 11 C women participated in this study. Fascicle lengths, tHb and TOI in the tibialis anterior muscle were measured during passive plantar flexion from ankle joint angles of 120° (baseline) to 140°, 160°, the maximal comfortable position without pain (CP), and the maximal position (MP). At 160°, the % fascicle-length change from baseline was significantly lower in the BT than the C group, however, for the changes in tHb and TOI the significant interaction effect between the 2 groups was not detected. On the other hand, although the increases in the fascicle length from baseline to CP and MP were greater in BT than C, the tHb and TOI reductions were comparable between groups. We concluded that it appears that BT can extend their muscles without excessive reduction in muscle-blood volume and muscle oxygenation at relatively same but absolutely greater muscle-stretching levels than C. The attenuation in these indices during high-level muscle stretching may be associated with the repetitive muscle stretching of long-term ballet training. © Georg Thieme Verlag KG Stuttgart · New York.

Effects of motexafin gadolinium on tumor oxygenation and cellular oxygen consumption

International Nuclear Information System (INIS)

Donnelly, E.T.; Liu, Y.; Rockwell, S.; Magda, D.

2003-01-01

Full text: Recent work in our laboratory showed that motexafin gadolinium (MGd, Xcytrin), a drug currently in Phase III clinical trials as an adjuvant to radiation therapy, modulates the oxygen tensions in EMT6 tumors. The median pO 2 increased from the control value of 1.5±0.4 mmHg to 7.4 ± 3.8 mmHg six hours after treatment with 40 μmol/kg MGd and the percentage of severely hypoxic readings in the tumors ( 7 plateau phase EMT6 cells in 3 mL Dulbecco's Modified Eagle's Medium supplemented with 10% dialyzed fetal bovine serum, which contains no ascorbic acid. In the absence of ascorbic acid, 100 μM MGd did not alter the cellular oxygen consumption rate for EMT6 cells significantly. Marked inhibition of cellular oxygen consumption was observed when cells were incubated with 100 μM MGd in medium supplemented with equimolar ascorbic acid (a 31.5% decrease in consumption was observed after 6 hours of treatment). The 5% mannitol vehicle solution with equimolar ascorbic acid had no discernible effect on cellular oxygen consumption. Ascorbic acid may facilitate cellular uptake of MGd via the intermediate formation of a MGd-oxalate complex. These studies suggest that changes in cellular oxygen consumption could contribute to the changes in tumor oxygenation seen after administration of MGd. These experiments were supported by Pharmacyclics and training grant T32CA09085 from the NIH (E.T.D.). We thank Dr. Raymond Russell for allowing us to use his oxygen electrode apparatus

Home monitoring of daytime mouthpiece ventilation effectiveness in patients with neuromuscular disease

Science.gov (United States)

Nardi, Julie; Leroux, Karl; Orlikowski, David; Prigent, Hélène

2015-01-01

Mouthpiece ventilation (MPV) allows patients with neuromuscular disease to receive daytime support from a portable ventilator, which they can disconnect at will, for example, for speaking, eating, swallowing, and coughing. However, MPV carries a risk of underventilation. Our purpose here was to evaluate the effectiveness of daytime MPV under real-life conditions. Eight wheelchair-bound patients who used MPV underwent daytime polygraphy at home with recordings of airflow, mouthpiece pressure, thoracic and abdominal movements, peripheral capillary oxygen saturation (SpO2), and transcutaneous partial pressure of carbon dioxide (PtcCO2). Times and durations of tasks and activities were recorded. The Apnea–Hypopnea Index (AHI) was computed. Patient–ventilator disconnections ≥3 minutes and episodes of hypoventilation defined as PtcCO2>45 mmHg were counted. Patient–ventilator asynchrony events were analyzed. The AHI was >5 hour−1 in two patients. Another patient experienced unexplained 3% drops in arterial oxygen saturations at a frequency of 70 hour−1. Patient–ventilator disconnections ≥3 minutes occurred in seven of eight patients and were consistently associated with decreases in SpO2 and ≥5-mmHg increases in PtcCO2; PtcCO2 rose above 45 mmHg in two patients during these disconnections. The most common type of patient–ventilator asynchrony was ineffective effort. This study confirms that MPV can be effective as long as the patient remains connected to the mouthpiece. However, transient arterial oxygen desaturation and hypercapnia due to disconnection from the ventilator may occur, without inducing unpleasant sensations in the patients. Therefore, an external warning system based on a minimal acceptable value of minute ventilation would probably be useful. PMID:26703922

Internal-reference solid-electrolyte oxygen sensor

International Nuclear Information System (INIS)

Haaland, D.M.

1977-01-01

A new solid-electrolyte oxygen sensor has been developed that eliminates the conventional oxygen reference in previous solid-electrolyte oxygen sensor designs and is, therefore, ideally suited as an insertion device for remote oxygen monitoring applications. It is constructed with two cells of stabilized zirconia sealed into a small unit using a new high-temperature platinum-zirconia seal. One electrochemical cell monitors the ratio of oxygen partial pressures inside and outside the sensor while the other solid-electrolyte cell is used for quantitative electrochemical pumping of oxygen. The internal oxygen reference is generated by initially pumping all oxygen out of the known internal volume of the sensor and then quantitatively pumping oxygen back in until oxygen partial pressures are equal inside and out. This information is used with the ideal gas law to calculate oxygen partial pressures. Tests were conducted from 400 to 1000 0 C in mixtures of oxygen and nitrogen spanning approximately 0.2 to 21 percent oxygen concentration range. Sensors with sputtered platinum and porous platinum paste electrodes were compared

Paradoxical arterial hypoxemia in a left-to-right shunt congenital heart disease.

Science.gov (United States)

Martínez-Quintana, Efrén; Rodríguez-González, Fayna

2014-01-01

The hepatopulmonary syndrome is a rare complication of different types of chronic hepatic diseases with associated portal venous hypertension, resulting in pulmonary vascular dilatation, predominantly in the lower lung fields, and leading to ventilation-perfusion mismatch, arterial hypoxemia and a poor prognosis. We present the case of 42-year-old male patient with an anomalous drainage of the right superior pulmonary vein into the azygos vein and a portal vein cavernomatosis with associated portal venous hypertension who presented severe oxygen desaturation, during exercise, in the context of a hepatopulmonary syndrome.

Non-self-sustained electric discharge in oxygen gas mixtures: singlet delta oxygen production

CERN Document Server

Ionin, A A; Kotkov, A A; Kochetov, I V; Napartovich, A P; Seleznev, L V; Sinitsyn, D V; Hager, G D

2003-01-01

The possibility of obtaining a high specific input energy in an electron-beam sustained discharge ignited in oxygen gas mixtures O sub 2 : Ar : CO (or H sub 2) at the total gas pressures of 10-100 Torr was experimentally demonstrated. The specific input energy per molecular component exceeded approx 6 kJ l sup - sup 1 atm sup - sup 1 (150 kJ mol sup - sup 1) as a small amount of carbon monoxide was added into a gas mixture of oxygen and argon. It was theoretically demonstrated that one might expect to obtain a singlet delta oxygen yield of 25% exceeding its threshold value needed for an oxygen-iodine laser operation at room temperature, when maintaining a non-self-sustained discharge in oxygen gas mixtures with molecular additives CO, H sub 2 or D sub 2. The efficiency of singlet delta oxygen production can be as high as 40%.

Ambient oxygen promotes tumorigenesis.

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Ho Joong Sung

2011-05-01

Full Text Available Oxygen serves as an essential factor for oxidative stress, and it has been shown to be a mutagen in bacteria. While it is well established that ambient oxygen can also cause genomic instability in cultured mammalian cells, its effect on de novo tumorigenesis at the organismal level is unclear. Herein, by decreasing ambient oxygen exposure, we report a ∼50% increase in the median tumor-free survival time of p53-/- mice. In the thymus, reducing oxygen exposure decreased the levels of oxidative DNA damage and RAG recombinase, both of which are known to promote lymphomagenesis in p53-/- mice. Oxygen is further shown to be associated with genomic instability in two additional cancer models involving the APC tumor suppressor gene and chemical carcinogenesis. Together, these observations represent the first report directly testing the effect of ambient oxygen on de novo tumorigenesis and provide important physiologic evidence demonstrating its critical role in increasing genomic instability in vivo.

Oxygen Tension in the Aqueous Humor of Human Eyes under Different Oxygenation Conditions

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Farideh Sharifipour

2013-01-01

Full Text Available Purpose: To measure oxygen tension in the aqueous humor of human eyes under different oxygenation conditions. Methods: This prospective comparative interventional case series consisted of two parts. In the first part, 120 consecutive patients scheduled for cataract surgery were randomized into group I (control group in which surgery was performed under local anesthesia inhaling 21% oxygen; group II in whom general anesthesia using 50% oxygen was employed; and group III receiving general anesthesia with 100% oxygen. After aspirating 0.2 ml aqueous humor under sterile conditions, the aqueous sample and a simultaneously drawn arterial blood sample were immediately analyzed using a blood gas analyzer. In part II the same procedures were performed in 10 patients after fitting a contact lens and patching the eye for 20 minutes (group IV and in 10 patients after transcorneal delivery of oxygen at a flow rate of 5 L/min (group V. Results: Mean aqueous PO2 in groups I, II and III was 112.3±6.2, 141.1±20.4, and 170.1±27 mmHg, respectively (P values <0.001 and mean arterial PO2 was 85.7±7.9, 184.6±46, and 379.1±75.9 mmHg, respectively (P values <0.001. Aqueous PO2 was 77.2±9.2 mmHg in group IV and 152.3±10.9 mmHg in group V (P values <0.001. There was a significant correlation between aqueous and blood PO2 (r=0.537, P<0.001. The contribution of atmospheric oxygen to aqueous PO2 was 23.7%. Conclusion: Aqueous oxygen tension is mostly dependent on the systemic circulation and in part on the atmosphere. Increasing inspiratory oxygen and transcorneal oxygen delivery both increase aqueous PO2 levels.

A Low-Pressure Oxygen Storage System for Oxygen Supply in Low-Resource Settings.

Science.gov (United States)

Rassool, Roger P; Sobott, Bryn A; Peake, David J; Mutetire, Bagayana S; Moschovis, Peter P; Black, Jim Fp

2017-12-01

Widespread access to medical oxygen would reduce global pneumonia mortality. Oxygen concentrators are one proposed solution, but they have limitations, in particular vulnerability to electricity fluctuations and failure during blackouts. The low-pressure oxygen storage system addresses these limitations in low-resource settings. This study reports testing of the system in Melbourne, Australia, and nonclinical field testing in Mbarara, Uganda. The system included a power-conditioning unit, a standard oxygen concentrator, and an oxygen store. In Melbourne, pressure and flows were monitored during cycles of filling/emptying, with forced voltage fluctuations. The bladders were tested by increasing pressure until they ruptured. In Mbarara, the system was tested by accelerated cycles of filling/emptying and then run on grid power for 30 d. The low-pressure oxygen storage system performed well, including sustaining a pressure approximately twice the standard working pressure before rupture of the outer bag. Flow of 1.2 L/min was continuously maintained to a simulated patient during 30 d on grid power, despite power failures totaling 2.9% of the total time, with durations of 1-176 min (mean 36.2, median 18.5). The low-pressure oxygen storage system was robust and durable, with accelerated testing equivalent to at least 2 y of operation revealing no visible signs of imminent failure. Despite power cuts, the system continuously provided oxygen, equivalent to the treatment of one child, for 30 d under typical power conditions for sub-Saharan Africa. The low-pressure oxygen storage system is ready for clinical field trials. Copyright © 2017 by Daedalus Enterprises.

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.

Simultaneous sampling of tissue oxygenation and oxygen consumption in skeletal muscle.

Science.gov (United States)

Nugent, William H; Song, Bjorn K; Pittman, Roland N; Golub, Aleksander S

2016-05-01

Under physiologic conditions, microvascular oxygen delivery appears to be well matched to oxygen consumption in respiring tissues. We present a technique to measure interstitial oxygen tension (PISFO2) and oxygen consumption (VO2) under steady-state conditions, as well as during the transitions from rest to activity and back. Phosphorescence Quenching Microscopy (PQM) was employed with pneumatic compression cycling to achieve 1 to 10 Hz sampling rates of interstitial PO2 and simultaneous recurrent sampling of VO2 (3/min) in the exteriorized rat spinotrapezius muscle. The compression pressure was optimized to 120-130 mmHg without adverse effect on the tissue preparation. A cycle of 5s compression followed by 15s recovery yielded a resting VO2 of 0.98 ± 0.03 ml O2/100 cm(3)min while preserving microvascular oxygen delivery. The measurement system was then used to assess VO2 dependence on PISFO2 at rest and further tested under conditions of isometric muscle contraction to demonstrate a robust ability to monitor the on-kinetics of tissue respiration and the compensatory changes in PISFO2 during contraction and recovery. The temporal and spatial resolution of this approach is well suited to studies seeking to characterize microvascular oxygen supply and demand in thin tissues. Copyright © 2015 Elsevier Inc. All rights reserved.

Kinetics of oxygen species in an electrically driven singlet oxygen generator

International Nuclear Information System (INIS)

Azyazov, V.N.; Torbin, A.P.; Pershin, A.A.; Mikheyev, P.A.; Heaven, M.C.

2015-01-01

Highlights: • Vibrational excitation of O_3 increases the rate constant for O_3 + O_2(a) → 2O_2(X) + O. • Vibrationally excited O_3 is produced by the O + O_2(X) + M → O_3 + M reaction. • Ozone concentrations are impacted by the reactions of vibrationally excited O_3. • Relevant to ozone concentrations in oxygen discharges and the upper atmosphere. - Abstract: The kinetics of oxygen species in the gaseous medium of a discharge singlet oxygen generator has been revisited. Vibrationally excited ozone O_3(υ) formed in O + O_2 recombination is thought to be a significant agent in the deactivation of singlet oxygen O_2(a"1Δ), oxygen atom removal and ozone formation. It is shown that the process O_3(υ ⩾ 2) + O_2(a"1Δ) → 2O_2 + O is the main O_2(a"1Δ) deactivation channel in the post-discharge zone. If no measures are taken to decrease the oxygen atom concentration, the contribution of this process to the overall O_2(a"1Δ) removal is significant, even in the discharge zone. A simplified model for the kinetics of vibrationally excited ozone is proposed. Calculations based on this model yield results that are in good agreement with the experimental data.

Comparative evaluation of the cerebral state index/sup TM/ and bispectral index/sup TM/ monitoring during propofol-remifentanil anesthesia for open heart surgery

International Nuclear Information System (INIS)

Shahbazi, S.; Saem, J.

2007-01-01

The Cerebral State index (CSI) is a new index based on electroencephalogram to monitor depth of anesthesia. Transferring guidelines for titration of the Bispectral index (BIS) to the CSI depends on their compatibility. We compared the relationship between BIS and CSI values during propofol-remifentanil anesthesia. Forty one adult patients about to have open heart surgeries were enrolled. The skin was prepped and electrodes of both monitors were applied according to the manufacturers recommendations. The anesthesia was induced by midazolam, propofol, remifentanil and pancuronium and maintained by propofol and remifentanil and 50% nitrous oxide in oxygen. The BIS and CSI values were recorded in 37 pre-determined milestones during the operation and the anesthetic drugs were adjusted according to clinical signs of light anesthesia regardless of the CSI or BIS values. The BIS and CSI values decreased progressively from pre induction values of 93.15 (55-100) and 88.86 (52-100) to post induction values of 38.72 (16-71) and 40.27 (5-69), respectively. These values showed good linear correlation during laryngoscopy, before and after surgical incision and during CPB; R=0.695 with determination coefficient of 0.483. We found a good correlation between BIS and CSI values. Our results might serve as a blue print for a rational translation of BIS into CSI values. (author)

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.

OXYGEN MANAGEMENT DURING ALCOHOLIC FERMENTATION

OpenAIRE

MOENNE VARGAS, MARÍA ISABE

2013-01-01

Oxygen additions are a common practice in winemaking, as oxygen has a positive effect in fermentative kinetics, biomass synthesis and improvement of color, structure and :flavor in treated wines. However, most oxygen additions are carried out heuristically through pump-over operations solely on a know-how basis, which is difficult to manage in terms of the exact quantity of oxygen transferred to the fermenting must. It is important to estímate the amount of oxygen added because...

Medical oxygen and air travel.

Science.gov (United States)

Lyznicki, J M; Williams, M A; Deitchman, S D; Howe, J P

2000-08-01

This report responds to a resolution that asked the American Medical Association (AMA) to take action to improve airport and airline accommodations for passengers requiring medical oxygen. Information for the report was derived from a search of the MEDLINE database and references listed in pertinent articles, as well as through communications with experts in aerospace and emergency medicine. Based on this information, the AMA Council on Scientific Affairs determined that commercial air travel exposes passengers to altitude-related hypoxia and gas expansion, which may cause some passengers to experience significant symptoms and medical complications during flight. Medical guidelines are available to help physicians evaluate and counsel potential passengers who are at increased risk of inflight hypoxemia. Supplemental oxygen may be needed for some passengers to maintain adequate tissue oxygenation and prevent hypoxemic complications. For safety and security reasons, federal regulations prohibit travelers from using their own portable oxygen system onboard commercial aircraft. Many U.S. airlines supply medical oxygen for use during flight but policies and procedures vary. Oxygen-dependent passengers must make additional arrangements for the use of supplemental oxygen in airports. Uniform standards are needed to specify procedures and equipment for the use of medical oxygen in airports and aboard commercial aircraft. Revision of federal regulations should be considered to accommodate oxygen-dependent passengers and permit them to have an uninterrupted source of oxygen from departure to destination.

Oxygen transport membrane

DEFF Research Database (Denmark)

2015-01-01

The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof.......The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof....

Lung recruitment maneuver effects on respiratory mechanics and extravascular lung water index in patients with acute respiratory distress syndrome.

Science.gov (United States)

Zhang, Jian-Guo; Chen, Xiao-Juan; Liu, Fen; Zeng, Zhen-Guo; Qian, Ke-Jian

2011-01-01

Animal experiments showed that recruitment maneuver (RM) and protective ventilation strategy of the lung could improve oxygenation and reduce extravascular lung water. This study was to investigate the effects of RM on respiratory mechanics and extravascular lung water index (EVLWI) in patients with acute respiratory distress syndrome (ARDS). Thirty patients with ARDS were randomized into a RM group and a non-RM group. In the RM group, after basic mechanical ventilation stabilized for 30 minutes, RM was performed and repeated once every 12 hours for 3 days. In the non-RM group, lung protective strategy was conducted without RM. Oxygenation index (PaO2/FiO2), peak inspiratory pressure (PIP), Plateau pressure (Pplat), static pulmonary compliance (Cst) and EVLWI of patients before treatment and at 12, 24, 48, 72 hours after the treatment were measured and compared between the groups. Hemodynamic changes were observed before and after RM. One-way ANOVA, Student's t test and Fisher's exact test were used to process the data. The levels of PaO2/FiO2 and Cst increased after treatment in the two groups, but they were higher in the RM group than in the non-RM group (P0.05). RM could reduce EVLWI, increase oxygenation and lung compliance. The effect of RM on hemodynamics was transient.

Integration of oxygen membranes for oxygen production in cement plants

DEFF Research Database (Denmark)

Puig Arnavat, Maria; Søgaard, Martin; Hjuler, Klaus

2015-01-01

The present paper describes the integration of oxygen membranes in cement plants both from an energy, exergy and economic point of view. Different configurations for oxygen enrichment of the tertiary air for combustion in the pre-calciner and full oxy-fuel combustion in both pre-calciner and kiln...

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.

Oxygenation measurements in head and neck cancers during hyperbaric oxygenation

International Nuclear Information System (INIS)

Becker, A.; Kuhnt, T.; Dunst, J.; Liedtke, H.; Krivokuca, A.; Bloching, M.

2002-01-01

Background: Tumor hypoxia has proven prognostic impact in head and neck cancers and is associated with poor response to radiotherapy. Hyperbaric oxygenation (HBO) offers an approach to overcome hypoxia. We have performed pO 2 measurements in selected patients with head and neck cancers under HBO to determine in how far changes in the oxygenation occur and whether a possible improvement of oxygenation parameters is maintained after HBO. Patients and Methods: Seven patients (five male, two female, age 51-63 years) with squamous cell cancers of the head and neck were investigated (six primaries, one local recurrence). The median pO 2 prior to HBO was determined with the Eppendorf histograph. Sites of measurement were enlarged cervical lymph nodes (n = 5), the primary tumor (n = 1) and local recurrence (n = 1). Patients then underwent HBO (100% O 2 at 240 kPa for 30 minutes) and the continuous changes in the oxygenation during HBO were determined with a Licox probe. Patients had HBO for 30 minutes (n = 6) to 40 minutes (n = 1). HBO was continued because the pO 2 had not reached a steady state after 30 minutes. After decompression, patients ventilated pure oxygen under normobaric conditions and the course of the pO 2 was further measured over about 15 minutes. Results: Prior to HBO, the median tumor pO 2 in the Eppendorf histography was 8.6 ± 5.4 mm Hg (range 3-19 mm Hg) and the pO 2 measured with the Licox probe was 17.3 ± 25.5 mm Hg (range 0-73 mm Hg). The pO 2 increased significantly during HBO to 550 ± 333 mm Hg (range 85-984 mm Hg, p = 0.018). All patients showed a marked increase irrespective of the oxygenation prior to HBO. The maximum pO 2 in the tumor was reached after 10-33 minutes (mean 17 minutes). After leaving the hyperbaric chamber, the pO 2 was 282 ± 196 mm Hg. All patients maintained an elevated pO 2 for further 5-25 minutes (138 ± 128 mm Hg, range 42-334 mm Hg, p = 0.028 vs the pO 2 prior to HBO). Conclusions: Hyperbaric oxygenation resulted in a

A Preliminary Study of Water Quality Index in Terengganu River Basin, Malaysia

International Nuclear Information System (INIS)

Suratman, S.; Mohd, S.M.I.; Hee, Y.Y.; Bedurus, E.A.; Latif, M.T.

2015-01-01

The Malaysian Department of Environment-Water Quality Index (DOE-WQI) was determined for the Terengganu River basin which is located at the coastal water of the southern South China Sea between July and October 2008. Monthly samplings were carried out at ten sampling stations within the basin. Six parameters listed in DOE-WQI were measured based on standard methods: pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS) and ammonical nitrogen (AN). The results indicated the impact of various anthropogenic activities which contribute to high values of BOD, COD, TSS and AN at middle and downstream stations, as compared with the upstream of the basin. The reverses were true for the pH and DO values. The DOE-WQI ranged from 71.5-94.6 % (mean 86.9 %), which corresponded to a classification status range from slightly polluted to clean. With respect to the Malaysia National Water Quality Standards (NWQS), the level of most of the parameters measured remained at Class I which is suitable for the sustainable conservation of the natural environment, for water supply without treatment and as well as for very sensitive aquatic species. It is suggested that monitoring should be carried out continuously for proper management of this river basin. (author)

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.

Kinetics of oxygen species in an electrically driven singlet oxygen generator

Energy Technology Data Exchange (ETDEWEB)

Azyazov, V.N., E-mail: azyazov@fian.smr.ru [Samara State Aerospace University, 443086 (Russian Federation); Lebedev Physical Institute of RAS, Samara 443011 (Russian Federation); Torbin, A.P.; Pershin, A.A. [Samara State Aerospace University, 443086 (Russian Federation); Lebedev Physical Institute of RAS, Samara 443011 (Russian Federation); Mikheyev, P.A., E-mail: mikheyev@fian.smr.ru [Samara State Aerospace University, 443086 (Russian Federation); Lebedev Physical Institute of RAS, Samara 443011 (Russian Federation); Heaven, M.C., E-mail: mheaven@emory.edu [Emory University, Atlanta, GA 30322 (United States)

2015-12-16

Highlights: • Vibrational excitation of O{sub 3} increases the rate constant for O{sub 3} + O{sub 2}(a) → 2O{sub 2}(X) + O. • Vibrationally excited O{sub 3} is produced by the O + O{sub 2}(X) + M → O{sub 3} + M reaction. • Ozone concentrations are impacted by the reactions of vibrationally excited O{sub 3}. • Relevant to ozone concentrations in oxygen discharges and the upper atmosphere. - Abstract: The kinetics of oxygen species in the gaseous medium of a discharge singlet oxygen generator has been revisited. Vibrationally excited ozone O{sub 3}(υ) formed in O + O{sub 2} recombination is thought to be a significant agent in the deactivation of singlet oxygen O{sub 2}(a{sup 1}Δ), oxygen atom removal and ozone formation. It is shown that the process O{sub 3}(υ ⩾ 2) + O{sub 2}(a{sup 1}Δ) → 2O{sub 2} + O is the main O{sub 2}(a{sup 1}Δ) deactivation channel in the post-discharge zone. If no measures are taken to decrease the oxygen atom concentration, the contribution of this process to the overall O{sub 2}(a{sup 1}Δ) removal is significant, even in the discharge zone. A simplified model for the kinetics of vibrationally excited ozone is proposed. Calculations based on this model yield results that are in good agreement with the experimental data.

A theoretical model for the effects of reduced hemoglobin-oxygen affinity on tumor oxygenation

International Nuclear Information System (INIS)

Kavanagh, Brian D.; Secomb, Timothy W.; Hsu, Richard; Lin, P.-S.; Venitz, Jurgen; Dewhirst, Mark W.

2002-01-01

Purpose: To develop a theoretical model for oxygen delivery to tumors, and to use the model to simulate the effects of changing the affinity of hemoglobin for oxygen on tumor oxygenation. Methods and Materials: Hemoglobin affinity is expressed in terms of P 50 , the partial pressure of oxygen (Po 2 ) at half saturation. Effects of changing P 50 on arterial Po 2 are predicted using an effective vessel approach to describe diffusive oxygen transport in the lungs, assuming fixed systemic oxygen demand and fixed blood flow rate. The decline in oxygen content of blood as it flows through normal tissue before entering the tumor region is assumed fixed. The hypoxic fraction of the tumor region is predicted using a three-dimensional simulation of diffusion from a network of vessels whose geometry is derived from observations of tumor microvasculature in the rat. Results: In air-breathing rats, predicted hypoxic fraction decreases with moderate increases in P 50 , but increases with further increases of P 50 , in agreement with previous experimental results. In rats breathing hyperoxic gases, and in humans breathing either normoxic or hyperoxic gases, increased P 50 is predicted to improve tumor oxygenation. Conclusions: The results support the administration of synthetic agents to increase P 50 during radiation treatment of tumors

Do Karst Rivers “deserve” their own biotic index? A ten years study on macrozoobenthos in Croatia

Directory of Open Access Journals (Sweden)

Rađa Biljana

2010-07-01

Full Text Available In this study we present the results of a ten year survey of the aquatic macroinvertebrate fauna along four karst rivers: Jadro, Žrnovnica, Grab and Ruda, all of them situated in the Middle Dalmatia region of Croatia, in an attempt to construct the Iliric Biotic Index, which will be more applicable for the water quality analysis than the most frequently applied biotic index in Croatia, the Italian Modification of Extended Biotic Index. The rivers geologically belong to the Dinaric karst, unique geological phenomena in Europe. Benthic macroinvertebrates were collected along each river at 15 sites by standard methods of sampling along with several physicochemical parameters, including: temperature, dissolved oxygen, carbon dioxide, alkalinity, hardness and pH. Univariate and multivariate techniques revealed differences in the macroinvertebrate community structure as well as in physicochemical parameters between the Karst rivers and continental rivers. Based on those differences, the Iliric Biotic Index was proposed as the standard of karst river water quality in Croatia in accordance with the EU Water Framework Directive. Differences between the Iliric Biotic Index and the most commonly used biotic indices in the European Community and the USA (The Biological Monitoring Working Party (B.M.W.P. scores, i.e. Extended Biotic Index, Indice Biotique, Family Biotic Index suggest that karst rivers need a new biotic index.

Optic nerve oxygenation

DEFF Research Database (Denmark)

Stefánsson, Einar; Pedersen, Daniella Bach; Jensen, Peter Koch

2005-01-01

The oxygen tension of the optic nerve is regulated by the intraocular pressure and systemic blood pressure, the resistance in the blood vessels and oxygen consumption of the tissue. The oxygen tension is autoregulated and moderate changes in intraocular pressure or blood pressure do not affect...... the optic nerve oxygen tension. If the intraocular pressure is increased above 40 mmHg or the ocular perfusion pressure decreased below 50 mmHg the autoregulation is overwhelmed and the optic nerve becomes hypoxic. A disturbance in oxidative metabolism in the cytochromes of the optic nerve can be seen...... at similar levels of perfusion pressure. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. The risk for progressive optic nerve atrophy in human...

The Circadian System Contributes to Apnea Lengthening across the Night in Obstructive Sleep Apnea.

Science.gov (United States)

Butler, Matthew P; Smales, Carolina; Wu, Huijuan; Hussain, Mohammad V; Mohamed, Yusef A; Morimoto, Miki; Shea, Steven A

2015-11-01

To test the hypothesis that respiratory event duration exhibits an endogenous circadian rhythm. Within-subject and between-subjects. Inpatient intensive physiologic monitoring unit at the Brigham and Women's Hospital. Seven subjects with moderate/severe sleep apnea and four controls, age 48 (SD = 12) years, 7 males. Subjects completed a 5-day inpatient protocol in dim light. Polysomnography was recorded during an initial control 8-h night scheduled at the usual sleep time, then through 10 recurrent cycles of 2 h 40 min sleep and 2 h 40 min wake evenly distributed across all circadian phases, and finally during another 8-h control sleep period. Event durations, desaturations, and apnea-hypopnea index for each sleep opportunity were assessed according to circadian phase (derived from salivary melatonin), time into sleep, and sleep stage. Average respiratory event durations in NREM sleep significantly lengthened across both control nights (21.9 to 28.2 sec and 23.7 to 30.2 sec, respectively). During the circadian protocol, event duration in NREM increased across the circadian phases that corresponded to the usual sleep period, accounting for > 50% of the increase across normal 8-h control nights. AHI and desaturations were also rhythmic: AHI was highest in the biological day while desaturations were greatest in the biological night. The endogenous circadian system plays an important role in the prolongation of respiratory events across the night, and might provide a novel therapeutic target for modulating sleep apnea. © 2015 Associated Professional Sleep Societies, LLC.

Water quality assessment of the Borska Reka river using the WPI (Water Pollution Index method

Directory of Open Access Journals (Sweden)

Milijašević Dragana

2011-01-01

Full Text Available The Borska Reka river (47 km long, 373 km2 of basin area is located in eastern Serbia and it is the biggest tributary of the river Veliki Timok. It is also one of the most polluted watercourses in Serbia. Using the data of the Republic Hydrometeorological Service of Serbia, the paper analyzes water pollution using the combined physical-chemical WPI index (water pollution index over two periods: 1993-1996 and 2006-2009. The analysis of parameters showed significantly increased values of heavy metals (especially iron and manganese which are indicators of inorganic pollution (primarily because of mining, but also increased values of organic pollution indicators (Biological Oxygen Demand-BOD5, ammonium, coliform germs, as the result of uncontrolled domestic wastewater discharge.

The relationship between neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio in patients with obstructive sleep apnea syndrome

Directory of Open Access Journals (Sweden)

Hülya Günbatar

2015-09-01

Full Text Available Objective: There is a strong relationship between obstructive sleep apnea syndrome (OSAS and cardiovascular disease (CVD. Chronic intermittent hypoxia, inflammation, oxidative stress, and endothelial dysfunction may create etiologic mechanisms, connection between OSAS to CVD. Inflammation play an important role in the development of CVD. Platelet- Lymphocyte Ratio (PLR and Neutrophil-lymphocyte Ratio (NLR are new biomarkers showing inflammation. This study was designed to investigate the association between PLR, NLR and relationship between severity of OSAS, polysomnographic parameters and PLR. Methods: This was a cohort study in which patients who had undergone a full night polysomnography for diagnosis of OSA were recruited. Patients were divided according to their apnea hypopnea index (AHI scores into OSAS negative simple snoring (Group 1; AHI 30 groups. Results: A total of 111 patients were included in this study. There were 26, 22 and 63 patients in Groups 1, 2 and 3, respectively. PLR were significantly different between groups (Group 1: 87.12, Group 2: 103.6, Group 3: 112.5, p < 0.05. PLR were significantly correlated with NLR, AHI, oxygen desaturation index, average and minimum O2 saturation values (p < 0.05. Multiple regression analysis demonstrated that PLR is an independent predictor of CVD. PLR cut-off value for demonstrating the presence of CVD is higher than 86.03. Conclusion: In the light of these findings, PLR is strongly associated with the severity of OSAS. PLR might be used as a biomarker to predict CVD in OSAS patients.

Oxygen and animal evolution: Did a rise of atmospheric oxygen trigger the origin of animals?

DEFF Research Database (Denmark)

Mills, Daniel Brady; Canfield, Donald Eugene

2014-01-01

Recent studies challenge the classical view that the origin of animal life was primarily controlled by atmospheric oxygen levels. For example, some modern sponges, representing early-branching animals, can live under 200 times less oxygen than currently present in the atmosphere - levels commonly...... thought to have been maintained prior to their origination. Furthermore, it is increasingly argued that the earliest animals, which likely lived in low oxygen environments, played an active role in constructing the well-oxygenated conditions typical of the modern oceans. Therefore, while oxygen is still...

Kinetics of oxygen uncoupling of a copper based oxygen carrier

International Nuclear Information System (INIS)

Hu, Wenting; Donat, Felix; Scott, S.A.; Dennis, J.S.

2016-01-01

Highlights: • The kinetics of a Cu-based oxygen carrier was determined using a TGA. • A diffusion model was applied to remove mass transfer effects from rate parameters. • Thermodynamics are separated from kinetics, usually difficult for the CLOU reaction. • The rate parameters correctly described the behaviour in a fluidised bed. • The rate parameters can be used to predict performance of large CLOU systems. - Abstract: Here, an oxygen carrier consisting of 60 wt% CuO supported on a mixture of Al_2O_3 and CaO (23 wt% and 17 wt% respectively) was synthesised by wet-mixing powdered CuO, Al(OH)_3 and Ca(OH)_2, followed by calcination at 1000 °C. Its suitability for chemical looping with oxygen uncoupling (CLOU) was investigated. After 25 repeated redox cycles in either a thermogravimetric analyser (TGA) or a laboratory-scale fluidised bed, (with 5 vol% H_2 in N_2 as the fuel, and air as the oxidant) no significant change in either the oxygen uncoupling capacity or the overall oxygen availability of the carrier was found. In the TGA, it was found that the rate of oxygen release from the material was controlled by intrinsic chemical kinetics and external transfer of mass from the surface of the particles to the bulk gas. By modelling the various resistances, values of the rate constant for the decomposition were obtained. The activation energy of the reaction was found to be 59.7 kJ/mol (with a standard error of 5.6 kJ/mol) and the corresponding pre-exponential factor was 632 m"3/mol/s. The local rate of conversion within a particle was assumed to occur either (i) by homogeneous chemical reaction, or (ii) in uniform, non-porous grains, each reacting as a kinetically-controlled shrinking core. Upon cross validation against a batch fluidised bed experiment, the homogeneous reaction model was found to be more plausible. By accurately accounting for the various artefacts (e.g. mass transfer resistances) present in both TGA and fluidised bed experiments, it was

Association of daytime sleepiness with obstructive sleep apnoea and comorbidities varies by sleepiness definition in a population cohort of men.

Science.gov (United States)

Adams, Robert J; Appleton, Sarah L; Vakulin, Andrew; Lang, Carol; Martin, Sean A; Taylor, Anne W; McEvoy, R Doug; Antic, Nick A; Catcheside, Peter G; Wittert, Gary A

2016-10-01

To determine correlates of excessive daytime sleepiness (EDS) identified with the Epworth Sleepiness Scale (ESS) and a more broad definition, while accounting for obstructive sleep apnoea (OSA) in community dwelling men. Participants of the Men Androgens Inflammation Lifestyle Environment and Stress (MAILES) Study (n = 837, ≥ 40 years) without a prior OSA diagnosis, underwent in-home full unattended polysomnography (PSG, Embletta X100), completed the ESS, STOP questionnaire and Pittsburgh Sleep Quality Index in 2010-2011. In 2007-2010, questionnaires and biomedical assessment (in South Australian public hospital-based clinics) identified medical conditions. An alternate EDS definition (EDSAlt ) consisted of ≥ 2 of 3 problems (feeling sleepy sitting quietly; feeling tired/fatigued/sleepy; trouble staying awake). EDSAlt (30.4%, n = 253), but not ESS ≥ 11 (EDSESS , 12.6%, n = 104), increased significantly across OSA severity and body mass index categories. In adjusted analyses, EDSESS was significantly associated with depression: odds ratio (OR), 95%CI: 2.2 (1.3-3.8) and nocturia: 2.0 (1.3-3.2). EDSAlt was associated with depression, financial stress, relationship, work-life balance problems and associations with nocturia and diabetes were borderline. After excluding men with EDSESS , EDSAlt was associated with oxygen desaturation index (3%) ≥ 16 and the highest arousal index quartile but not with comorbidities. Sleepiness not necessarily leading to dozing, but not ESS ≥ 11, was related to sleep disordered breathing. Clinicians should be alert to (1) differing perspectives of sleepiness for investigation and treatment of OSA, and (2) the presence of depression and nocturia in men presenting with significant Epworth sleepiness regardless of the presence of OSA. © 2016 Asian Pacific Society of Respirology.

Effects of upper-airway stimulation on sleep architecture in patients with obstructive sleep apnea.

Science.gov (United States)

Hofauer, Benedikt; Philip, Pierre; Wirth, Markus; Knopf, Andreas; Heiser, Clemens

2017-12-01

Selective upper-airway stimulation (UAS) is a novel therapy for patients with obstructive sleep apnea (OSA). The aim of this study was to compare changes in sleep architecture during the diagnostic polysomnography and the post-implantation polysomnography in UAS in patients with OSA. Twenty-six patients who received a UAS device (Inspire Medical Systems) were included. Treatment outcome was evaluated 2 and 3 months after surgery. Data collection included demographics, body mass index (BMI), apnea hypopnea index (AHI), oxygen saturation and desaturation index (ODI), Epworth sleepiness score (ESS), arousal parameter, and sleep patterns. The mean age was 60.2 years, 25 patients were male, 1 patient was female. Mean BMI was 29.0 kg/m 2 . The mean pre-implantation AHI of 33.9/h could be reduced to 9.1/h at 2 months post-implantation (p < 0.001). The amount of time spent in N1-sleep could be reduced from 23.2% at baseline to 16.0% at month 3 post-implantation. The amount of time spent in N2- and N3-sleep did not change during the observation period. A significant increase of the amount of REM sleep at month 2 (15.7%) compared to baseline (9.5%; p = 0.010) could be observed. A reduction of the number of arousals and the arousal index could be observed. In conclusion, significant changes in sleep architecture of patients with OSA and sufficient treatment with UAS could be observed. A reduction of the amount of time spent in N1-sleep could be caused by treatment with UAS and the rebound of REM sleep, observed for the first time in a study on UAS, is also a potential marker of the efficacy of UAS on sleep architecture. NCT02293746.

Heme biomolecule as redox mediator and oxygen shuttle for efficient charging of lithium-oxygen batteries

Science.gov (United States)

Ryu, Won-Hee; Gittleson, Forrest S.; Thomsen, Julianne M.; Li, Jinyang; Schwab, Mark J.; Brudvig, Gary W.; Taylor, André D.

2016-01-01

One of the greatest challenges with lithium-oxygen batteries involves identifying catalysts that facilitate the growth and evolution of cathode species on an oxygen electrode. Heterogeneous solid catalysts cannot adequately address the problematic overpotentials when the surfaces become passivated. However, there exists a class of biomolecules which have been designed by nature to guide complex solution-based oxygen chemistries. Here, we show that the heme molecule, a common porphyrin cofactor in blood, can function as a soluble redox catalyst and oxygen shuttle for efficient oxygen evolution in non-aqueous Li-O2 batteries. The heme's oxygen binding capability facilitates battery recharge by accepting and releasing dissociated oxygen species while benefiting charge transfer with the cathode. We reveal the chemical change of heme redox molecules where synergy exists with the electrolyte species. This study brings focus to the rational design of solution-based catalysts and suggests a sustainable cross-link between biomolecules and advanced energy storage. PMID:27759005

Hypoxia Pathway Proteins As Central Mediators of Metabolism in the Tumor Cells and Their Microenvironment

Directory of Open Access Journals (Sweden)

Sundary Sormendi

2018-01-01

Full Text Available Low oxygen tension or hypoxia is a determining factor in the course of many different processes in animals, including when tissue expansion and cellular metabolism result in high oxygen demands that exceed its supply. This is mainly happening when cells actively proliferate and the proliferating mass becomes distant from the blood vessels, such as in growing tumors. Metabolic alterations in response to hypoxia can be triggered in a direct manner, such as the switch from oxidative phosphorylation to glycolysis or inhibition of fatty acid desaturation. However, as the modulated action of hypoxia-inducible factors or the oxygen sensors (prolyl hydroxylase domain-containing enzymes can also lead to changes in enzyme expression, these metabolic changes can also be indirect. With this review, we want to summarize our current knowledge of the hypoxia-induced changes in metabolism during cancer development, how they are affected in the tumor cells and in the cells of the microenvironment, most prominently in immune cells.

Nitric Oxide is Required for Homeostasis of Oxygen and Reactive Oxygen Species in Barley Roots under Aerobic Conditions

DEFF Research Database (Denmark)

Gupta, Kapuganti J; Hebelstrup, Kim; Kruger, Nicholas J

2014-01-01

Oxygen, the terminal electron acceptor for mitochondrial electron transport, is vital for plants because of its role in the production of ATP by oxidative phosphorylation. While photosynthetic oxygen production contributes to the oxygen supply in leaves, reducing the risk of oxygen limitation of ...... electron transport chain (Gupta et al., 2011). Thus, NO could influence oxygen consumption under normal aerobic conditions in roots, and it is this specific function that is assessed here.......Oxygen, the terminal electron acceptor for mitochondrial electron transport, is vital for plants because of its role in the production of ATP by oxidative phosphorylation. While photosynthetic oxygen production contributes to the oxygen supply in leaves, reducing the risk of oxygen limitation...

High Selectivity Oxygen Delignification

Energy Technology Data Exchange (ETDEWEB)

Lucian A. Lucia

2005-11-15

Project Objective: The objectives of this project are as follows: (1) Examine the physical and chemical characteristics of a partner mill pre- and post-oxygen delignified pulp and compare them to lab generated oxygen delignified pulps; (2) Apply the chemical selectivity enhancement system to the partner pre-oxygen delignified pulps under mill conditions (with and without any predetermined amounts of carryover) to determine how efficiently viscosity is preserved, how well selectivity is enhanced, if strength is improved, measure any yield differences and/or bleachability differences; and (3) Initiate a mill scale oxygen delignification run using the selectivity enhancement agent, collect the mill data, analyze it, and propose any future plans for implementation.

Investigation of the singlet delta oxygen and ozone yields from the pulsed radiolysis of oxygen and oxygen-noble gas mixtures

International Nuclear Information System (INIS)

Zediker, M.S.

1984-01-01

The experiments discussed herein were performed with a flowing gas apparatus coupled to the University of Illinois TRIGA reactor. The detectors (lambda = 1.27 μ 634 nm) were calibrated with a novel NO 2 titration scheme and the absorbed dose was estimated from the ozone concentrations measured in pure oxygen. The results of these experiments revealed an O 2 (a 1 Δ) production efficiency of 0.14% for direct nuclear pumping in an argon-oxygen mixture. Extensive modeling of the oxygen and argon-oxygen mixtures were benchmarked against these and other experiments. However, good agreement over a broad absorbed dose range was only possible if the O 4 + + O 4 - neutralization reaction was assumed to be nondissociative. In a second set of experiments with a nuclear sustained electrical discharge (low E/N), the O 2 (a 1 Δ) production efficiency was approx.0.40% for the electrical power densities examined. In addition, the O 2 (a 1 Δ) was observed to scale with the square root of the electrical power deposition but was independent of the oxygen concentration. A simple analytic model was developed which explains this behavior as a characteristic of an externally sustained discharge involving an electron attaching gas such as oxygen. The results of these experiments and the modeling of the chemical kinetics are discussed with an emphasis on optimizing the O 2 (a 1 Δ) and O 3 yields

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)

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.

Conscious sedation for patients undergoing enteroclysis: Comparing the safety and patient-reported effectiveness of two protocols

International Nuclear Information System (INIS)

Maglinte, Dean D.T.; Applegate, Kimberly E.; Rajesh, Arumugam; Jennings, S. Gregory; Ford, Jason M.; Savabi, Mojgan Sarah; Lappas, John C.

2009-01-01

Objective: To compare the safety and patient-reported effectiveness of two regimens for conscious sedation during enteroclysis. Materials and methods: We surveyed two groups of outpatients and retrospectively reviewed procedure records for conscious sedation and complications. Patients were divided into Group One (received sedative/amnesic diazepam), and Group Two, (received amnesic/sedative, midazolam and analgesic fentanyl). Results: All enteroclyses were successfully completed; there were no hospital admissions due to complications. In Group One (n = 106), mean dose of diazepam was 12.7 mg. 25% had oxygen desaturation (n = 25), and post-procedure vomiting without aspiration (n = 1). 56% of outpatients completed phone surveys, and 68% recalled procedural discomfort. In Group Two (n = 45), mean doses were 3.9 mg midazolam and 108 mcg fentanyl. 31% had desaturation (n = 13), and post-procedure vomiting without aspiration (n = 1). 87% had only a vague recall of the procedure or of any discomfort. Conclusion: A combination of amnesic and fentanyl prevented the recall of discomfort of nasoenteric intubation and infusion in most patients who had enteroclysis compared to diazepam. Most of the patients would undergo the procedure again, if needed.

Conscious sedation for patients undergoing enteroclysis: Comparing the safety and patient-reported effectiveness of two protocols

Energy Technology Data Exchange (ETDEWEB)

Maglinte, Dean D.T. [Department of Radiology, Indiana University Medical Center, 550 N, University Boulevard, University Hospital Room 0279, Indianapolis, IN 46202-5253 (United States)], E-mail: dmaglint@iupui.edu; Applegate, Kimberly E.; Rajesh, Arumugam; Jennings, S. Gregory; Ford, Jason M. [Department of Radiology, Indiana University Medical Center, 550 N, University Boulevard, University Hospital Room 0279, Indianapolis, IN 46202-5253 (United States); Savabi, Mojgan Sarah [Division of Gastroenterology, Department of Medicine, Indiana University School of Medicine, 550 N, University Boulevard, Indianapolis, IN 46202-5253 (United States); Lappas, John C. [Department of Radiology, Indiana University Medical Center, 550 N, University Boulevard, University Hospital Room 0279, Indianapolis, IN 46202-5253 (United States)

2009-06-15

Objective: To compare the safety and patient-reported effectiveness of two regimens for conscious sedation during enteroclysis. Materials and methods: We surveyed two groups of outpatients and retrospectively reviewed procedure records for conscious sedation and complications. Patients were divided into Group One (received sedative/amnesic diazepam), and Group Two, (received amnesic/sedative, midazolam and analgesic fentanyl). Results: All enteroclyses were successfully completed; there were no hospital admissions due to complications. In Group One (n = 106), mean dose of diazepam was 12.7 mg. 25% had oxygen desaturation (n = 25), and post-procedure vomiting without aspiration (n = 1). 56% of outpatients completed phone surveys, and 68% recalled procedural discomfort. In Group Two (n = 45), mean doses were 3.9 mg midazolam and 108 mcg fentanyl. 31% had desaturation (n = 13), and post-procedure vomiting without aspiration (n = 1). 87% had only a vague recall of the procedure or of any discomfort. Conclusion: A combination of amnesic and fentanyl prevented the recall of discomfort of nasoenteric intubation and infusion in most patients who had enteroclysis compared to diazepam. Most of the patients would undergo the procedure again, if needed.

The oxic degradation of sedimentary organic matter 1400 Ma constrains atmospheric oxygen levels

DEFF Research Database (Denmark)

Zhang, Shuichang; Wang, Xiaomei; Wang, Huajian

2017-01-01

shales are enriched in redox-sensitive trace metals, have high concentrations of total organic carbon (TOC), high hydrogen index (HI) and iron speciation indicating deposition under anoxic conditions. In contrast, the green-gray shales show no trace metal enrichments, have low TOC, low HI and iron...... speciation consistent with an oxygenated depositional setting. Altogether, unit 1 displays alternations between oxic and anoxic depositional environments, driving differences in carbon preservation consistent with observations from the modern ocean. We combined our TOC and HI results to calculate...

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.

Microsensor and transcriptomic signatures of oxygen depletion in biofilms associated with chronic wounds: Biofilms and oxygen

Energy Technology Data Exchange (ETDEWEB)

James, Garth A. [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Ge Zhao, Alice [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Usui, Marcia [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Underwood, Robert A. [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Nguyen, Hung [The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman Washington; Beyenal, Haluk [The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman Washington; deLancey Pulcini, Elinor [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Agostinho Hunt, Alessandra [Department of Microbiology and Molecular Genetics, 5180 Biomedical and Physical Sciences, Michigan State University, East Lansing Michigan; Bernstein, Hans C. [Pacific Northwest National Laboratory, Chemical and Biological Signature Science, Richland Washington; Fleckman, Philip [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Olerud, John [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Williamson, Kerry S. [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Franklin, Michael J. [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Stewart, Philip S. [Center for Biofilm Engineering, Montana State University, Bozeman Montana

2016-02-16

Polymicrobial biofilms have been implicated in delayed wound healing, although the mechanisms by which biofilms impair wound healing are poorly understood. Many species of bacteria produce exotoxins and exoenzymes that may inhibit healing. In addition, oxygen consumption by biofilms may impede wound healing. In this study, we used oxygen microsensors to measure oxygen transects through in vitro-cultured biofilms, biofilms formed in vivo in a diabetic (db/db) mouse model, and ex vivo human chronic wound specimens. The results show that oxygen levels within both euthanized and live mouse wounds had steep gradients that reached minima ranging from 19 to 61% oxygen partial pressure, compared to atmospheric oxygen levels. The oxygen gradients in the mouse wounds were similar to those observed for clinical isolates cultured in vitro and for human ex vivo scabs. No oxygen gradients were observed for heat-killed scabs, suggesting that active metabolism by the viable bacteria contributed to the reduced oxygen partial pressure of the wounds. To characterize the metabolic activities of the bacteria in the mouse wounds, we performed transcriptomics analyses of Pseudomonas aeruginosa biofilms associated with the db/db mice wounds using Affymetrix microarrays. The results demonstrated that the bacteria expressed genes for metabolic activities associated with cell growth. Interestingly, the transcriptome results indicated that the bacteria within the wounds also experienced oxygen-limitation stress. Among the bacterial genes that were expressed in vivo were genes associated with the Anr-mediated hypoxia-stress response. Other bacterial stress response genes highly expressed in vivo were genes associated with stationary-phase growth, osmotic stress, and RpoH-mediated heat shock stress. Overall, the results support the hypothesis that the metabolic activities of bacteria in biofilms act as oxygen sinks in chronic wounds and that the depletion of oxygen contributes to the

Effects of the Oxygenation level on Formation of Different Reactive Oxygen Species During Photodynamic Therapy

OpenAIRE

Price, Michael; Heilbrun, Lance; Kessel, David

2013-01-01

We examined the effect of the oxygenation level on efficacy of two photosensitizing agents, both of which target lysosomes for photodamage but via different photochemical pathways. Upon irradiation, the chlorin termed NPe6 forms singlet oxygen in high yield while the bacteriopheophorbide WST11 forms only oxygen radicals (in an aqueous environment). Photokilling efficacy by WST11 in cell culture was impaired when the atmospheric oxygen concentration was reduced from 20% to 1%, while photokilli...

Fanconi anaemia with bilateral diffuse pulmonary arterio venous fistulae: a case report

Directory of Open Access Journals (Sweden)

Samarakoon Lasitha

2012-03-01

Full Text Available Abstract Background We report a patient with cytogenetically confirmed Fanconi anaemia with associated diffuse bilateral pulmonary arterio-venous fistulae. This is only the second reported case of diffuse pulmonary arterio-venous fistulae with Fanconi anaemia. Case Presentation A 16 year old Sri Lankan boy, with a cytogenetically confirmed Fanconi anaemia was admitted to University Medical Unit, National Hospital of Sri Lanka for further assessment and treatment. Both central and peripheral cyanosis plus clubbing were noted on examination. The peripheral saturation was persistently low on room air and did not improve with supplementary Oxygen. Contrast echocardiography failed to demonstrate an intra cardiac shunt but showed early crossover of contrast, suggesting the possibility of pulmonary arterio-venous fistulae. Computed tomography pulmonary angiogram was inconclusive. Subsequent right heart catheterisation revealed bilateral diffuse arterio-venous fistulae not amenable for device closure or surgical intervention. Conclusion To our knowledge, this is the second reported patient with diffuse pulmonary arterio-venous fistulae associated with Fanconi anaemia. We report this case to create awareness among clinicians regarding this elusive association. We recommend screening patients with Fanconi anaemia using contrast echocardiography at the time of assessment with transthoracic echocardiogram. Though universal screening may be impossible given the cost constraints, such screening should at least be performed in patients with clinical evidence of desaturation or when a therapeutic option such as haematopoietic stem cell transplantation is considered. Treatment of pulmonary arteriovenous fistulae would improve patient outcome as desaturation by shunting worsens the anaemic symptoms by reducing the oxygen carrying capacity of blood.

Study on Brewster angle thin film polarizer using hafnia-silica mixture as high-refractive-index material

Science.gov (United States)

Xu, Nuo; Zhu, Meiping; Sun, Jian; Chai, Yingjie; Kui, Yi; Zhao, Yuanan; Shao, Jianda

2018-02-01

Two kinds of polarizer coatings were prepared by electron beam evaporation, using HfO2-SiO2 mixture and HfO2 as the high-refractive-index materials, respectively. The HfO2-SiO2 mixture layer was implemented by coevaporating SiO2 and metal Hf, the materials were deposited at an oxygen atmosphere to achieve stoichiometric coatings. The certain HfO2 and SiO2 content ratio is controlled by adjusting the deposition rate of HfO2 and SiO2 using individual quartz crystal monitor. The spectral performance, surface and interfacial properties, as well as the laser-induced damage performance were studied and compared. Comparing with polarizer coating using HfO2 as high-refractive-index material, the polarizer coating using HfO2-SiO2 mixture as high-refractive-index material shows better performance with broader polarizing bandwidth, lower surface roughness, better interfacial property while maintaining high laser-induced damage threshold.

Determining the Source of Water Vapor in a Cerium Oxide Electrochemical Oxygen Separator to Achieve Aviator Grade Oxygen

Science.gov (United States)

Graf, John; Taylor, Dale; Martinez, James

2014-01-01

More than a metric ton of water is transported to the International Space Station (ISS) each year to provide breathing oxygen for the astronauts. Water is a safe and compact form of stored oxygen. The water is electrolyzed on ISS and ambient pressure oxygen is delivered to the cabin. A much smaller amount of oxygen is used each year in spacesuits to conduct Extra Vehicular Activities (EVAs). Space suits need high pressure (>1000 psia) high purity oxygen (must meet Aviator Breathing Oxygen "ABO" specifications, >99.5% O2). The water / water electrolysis system cannot directly provide high pressure, high purity oxygen, so oxygen for EVAs is transported to ISS in high pressure gas tanks. The tanks are relatively large and heavy, and the majority of the system launch weight is for the tanks and not the oxygen. Extracting high purity oxygen from cabin air and mechanically compressing the oxygen might enable on-board production of EVA grade oxygen using the existing water / water electrolysis system. This capability might also benefit human spaceflight missions, where oxygen for EVAs could be stored in the form of water, and converted into high pressure oxygen on-demand. Cerium oxide solid electrolyte-based ion transport membranes have been shown to separate oxygen from air, and a supported monolithic wafer form of the CeO2 electrolyte membrane has been shown to deliver oxygen at pressures greater than 300 psia. These supported monolithic wafers can withstand high pressure differentials even though the membrane is very thin, because the ion transport membrane is supported on both sides (Fig 1). The monolithic supported wafers have six distinct layers, each with matched coefficients of thermal expansion. The wafers are assembled into a cell stack which allows easy air flow across the wafers, uniform current distribution, and uniform current density (Fig 2). The oxygen separation is reported to be "infinitely selective" to oxygen [1] with reported purity of 99.99% [2

Spatially monitoring oxygen level in 3D microfabricated cell culture systems using optical oxygen sensing beads

OpenAIRE

Wang, Lin; Acosta, Miguel A.; Leach, Jennie B.; Carrier, Rebecca L.

2013-01-01

Capability of measuring and monitoring local oxygen concentration at the single cell level (tens of microns scale) is often desirable but difficult to achieve in cell culture. In this study, biocompatible oxygen sensing beads were prepared and tested for their potential for real-time monitoring and mapping of local oxygen concentration in 3D micro-patterned cell culture systems. Each oxygen sensing bead is composed of a silica core loaded with both an oxygen sensitive Ru(Ph2phen3)Cl2 dye and ...

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

Oxygen Deficit: The Bio-energetic Pathophysiology

Directory of Open Access Journals (Sweden)

ABHAY KUMAR PANDEY

2014-09-01

Full Text Available Scarcity of oxygen in humans arises via three modes. The environment may have low oxygen to breath. There can be disease in respiratory system causing hindrance to uptake of oxygen from environment and the circulatory system may be sluggish to supply to body parts that starve for oxygen. Thirdly the chemico-cellular components of blood which carry oxygen may be lowered or defective. In reference to body cells several limiting sites and mechanisms affect the amount of oxygen delivered to them, and these are under regulatory control of several functional and metabolic systems.

MR Imaging-derived Oxygen-Hemoglobin Dissociation Curves and Fetal-Placental Oxygen-Hemoglobin Affinities.

Science.gov (United States)

Avni, Reut; Golani, Ofra; Akselrod-Ballin, Ayelet; Cohen, Yonni; Biton, Inbal; Garbow, Joel R; Neeman, Michal

2016-07-01

Purpose To generate magnetic resonance (MR) imaging-derived, oxygen-hemoglobin dissociation curves and to map fetal-placental oxygen-hemoglobin affinity in pregnant mice noninvasively by combining blood oxygen level-dependent (BOLD) T2* and oxygen-weighted T1 contrast mechanisms under different respiration challenges. Materials and Methods All procedures were approved by the Weizmann Institutional Animal Care and Use Committee. Pregnant mice were analyzed with MR imaging at 9.4 T on embryonic days 14.5 (eight dams and 58 fetuses; imprinting control region ICR strain) and 17.5 (21 dams and 158 fetuses) under respiration challenges ranging from hyperoxia to hypoxia (10 levels of oxygenation, 100%-10%; total imaging time, 100 minutes). A shorter protocol with normoxia to hyperoxia was also performed (five levels of oxygenation, 20%-100%; total imaging time, 60 minutes). Fast spin-echo anatomic images were obtained, followed by sequential acquisition of three-dimensional gradient-echo T2*- and T1-weighted images. Automated registration was applied to align regions of interest of the entire placenta, fetal liver, and maternal liver. Results were compared by using a two-tailed unpaired Student t test. R1 and R2* values were derived for each tissue. MR imaging-based oxygen-hemoglobin dissociation curves were constructed by nonlinear least square fitting of 1 minus the change in R2*divided by R2*at baseline as a function of R1 to a sigmoid-shaped curve. The apparent P50 (oxygen tension at which hemoglobin is 50% saturated) value was derived from the curves, calculated as the R1 scaled value (x) at which the change in R2* divided by R2*at baseline scaled (y) equals 0.5. Results The apparent P50 values were significantly lower in fetal liver than in maternal liver for both gestation stages (day 14.5: 21% ± 5 [P = .04] and day 17.5: 41% ± 7 [P hemoglobin dissociation curves with a shorter protocol that excluded the hypoxic periods was demonstrated. Conclusion MR imaging

Oxygen-reducing catalyst layer

Science.gov (United States)

O'Brien, Dennis P [Maplewood, MN; Schmoeckel, Alison K [Stillwater, MN; Vernstrom, George D [Cottage Grove, MN; Atanasoski, Radoslav [Edina, MN; Wood, Thomas E [Stillwater, MN; Yang, Ruizhi [Halifax, CA; Easton, E Bradley [Halifax, CA; Dahn, Jeffrey R [Hubley, CA; O'Neill, David G [Lake Elmo, MN

2011-03-22

An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

Extra-cerebral oxygenation influence on near-infrared-spectroscopy-determined frontal lobe oxygenation in healthy volunteers

DEFF Research Database (Denmark)

Sørensen, Henrik; Rasmussen, Peter; Siebenmann, Christoph

2015-01-01

INTRODUCTION: Frontal lobe oxygenation (Sc O2 ) is assessed by spatially resolved near-infrared spectroscopy (SR-NIRS) although it seems influenced by extra-cerebral oxygenation. We aimed to quantify the impact of extra-cerebral oxygenation on two SR-NIRS derived Sc O2 . METHODS: Multiple...... regression analysis estimated the influence of extra-cerebral oxygenation as exemplified by skin oxygenation (Sskin O2 ) on Sc O2 in 21 healthy subjects exposed to whole-body exercise in hypoxia (Fi O2 = 12%; n = 10) and normoxia (n = 12), whole-body heating, hyperventilation (n = 21), administration...... of norepinephrine with and without petCO2 -correction (n = 15), phenylephrine and head-up tilt (n = 7). Sc O2 was assessed simultaneously by NIRO-200NX (Sniro O2 ) and INVOS-4100 (Sinvos O2 ). Arterial (Sa O2 ) and jugular bulb oxygen saturations (Sj O2 ) were obtained. RESULTS: The regression analysis indicated...

Bispectral Index Monitoring Reduces the Dosage of Propofol and Adverse Events in Sedation for Endobronchial Ultrasound.

Science.gov (United States)

Quesada, Natividad; Júdez, Diego; Martínez Ubieto, Javier; Pascual, Ana; Chacón, Enrique; De Pablo, Francisco; Mincholé, Elisa; Bello, Salvador

2016-01-01

Current guidelines recommend monitoring the anesthetic depth of sedation during respiratory endoscopy by using clinical scales despite their subjective nature and the potential change in the level of sedation caused by frequent stimulation. Monitoring by means of the bispectral index (BIS) has shown its utility in reducing the use of drugs and their adverse events in general anesthesia, but evidence in prolonged sedation is insufficient. Our objective was to evaluate BIS in patients undergoing endobronchial ultrasound (EBUS). A randomized cohort study of 90 patients with mediastinal lymph node involvement and/or lung or mediastinal lesions for whom EBUS was indicated, comparing the modified observer's assessment of alertness/sedation scale clinical evaluation (n = 45) versus the BIS evaluation (n = 45) of sedation with propofol-remifentanil, was conducted in order to evaluate the clinical parameters, doses used, adverse events, and tolerance of the procedure. We found a shorter waking time and a significantly lower dose of total propofol in the BIS group. Significantly fewer overall adverse events were recorded in the BIS group and included desaturation, hypotension, and bradypnea. Tolerance was better in the BIS group. No significant differences were found in terms of cough, memory of the procedure, or the level of difficulty of EBUS on the part of the pulmonologists. BIS monitoring of sedation in EBUS makes it possible to reduce the dosage of propofol, thereby shortening the waking time and reducing adverse events. This form of monitoring should be taken into consideration in the future for systematic use in prolonged sedation, as in the case of EBUS. © 2016 S. Karger AG, Basel.

Effect of oxygen vacancies on the electronic and optical properties of tungsten oxide from first principles calculations

Science.gov (United States)

Mehmood, Faisal; Pachter, Ruth; Murphy, Neil R.; Johnson, Walter E.; Ramana, Chintalapalle V.

2016-12-01

In this work, we investigated theoretically the role of oxygen vacancies on the electronic and optical properties of cubic, γ-monoclinic, and tetragonal phases of tungsten oxide (WO3) thin films. Following the examination of structural properties and stability of the bulk tungsten oxide polymorphs, we analyzed band structures and optical properties, applying density functional theory (DFT) and GW (Green's (G) function approximation with screened Coulomb interaction (W)) methods. Careful benchmarking of calculated band gaps demonstrated the importance of using a range-separated functional, where results for the pristine room temperature γ-monoclinic structure indicated agreement with experiment. Further, modulation of the band gap for WO3 structures with oxygen vacancies was quantified. Dielectric functions for cubic WO3, calculated at both the single-particle, essentially time-dependent DFT, as well as many-body GW-Bethe-Salpeter equation levels, indicated agreement with experimental data for pristine WO3. Interestingly, we found that introducing oxygen vacancies caused appearance of lower energy absorptions. A smaller refractive index was indicated in the defective WO3 structures. These predictions could lead to further experiments aimed at tuning the optical properties of WO3 by introducing oxygen vacancies, particularly for the lower energy spectral region.

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

Walkability Index

Science.gov (United States)

The Walkability Index dataset characterizes every Census 2010 block group in the U.S. based on its relative walkability. Walkability depends upon characteristics of the built environment that influence the likelihood of walking being used as a mode of travel. The Walkability Index is based on the EPA's previous data product, the Smart Location Database (SLD). Block group data from the SLD was the only input into the Walkability Index, and consisted of four variables from the SLD weighted in a formula to create the new Walkability Index. This dataset shares the SLD's block group boundary definitions from Census 2010. The methodology describing the process of creating the Walkability Index can be found in the documents located at ftp://newftp.epa.gov/EPADataCommons/OP/WalkabilityIndex.zip. You can also learn more about the Smart Location Database at https://edg.epa.gov/data/Public/OP/Smart_Location_DB_v02b.zip.

The oxygen effect and cellular adaptation

International Nuclear Information System (INIS)

Meshcherikova, V.V.; Vajnson, A.A.; Yarmonenko, S.P.

1979-01-01

The radiomodifying effect of oxygen was shown to depend on the level of cellular oxygenation prior to irradiation. Acute hypoxia created at the time of irradiation protects previously normally oxygenated cells with DMF approximately 1.4 times larger than that of cells cultured for 24 hours under conditions of mild hypoxia. It is suggested that a decrease in the radioprotective effect of acute hypoxia on chronically hypoxic cells is correlated with an appreciable decrease in the rate of oxygen consumption by these cells, due to which the oxygen concentration near the intracellular targets in chronically hypoxic cells may be higher than in normal cells under conditions of poor oxygenation

Interplay between O2 and SnO2: oxygen ionosorption and spectroscopic evidence for adsorbed oxygen.

Science.gov (United States)

Gurlo, Alexander

2006-10-13

Tin dioxide is the most commonly used material in commercial gas sensors based on semiconducting metal oxides. Despite intensive efforts, the mechanism responsible for gas-sensing effects on SnO(2) is not fully understood. The key step is the understanding of the electronic response of SnO(2) in the presence of background oxygen. For a long time, oxygen interaction with SnO(2) has been treated within the framework of the "ionosorption theory". The adsorbed oxygen species have been regarded as free oxygen ions electrostatically stabilized on the surface (with no local chemical bond formation). A contradiction, however, arises when connecting this scenario to spectroscopic findings. Despite trying for a long time, there has not been any convincing spectroscopic evidence for "ionosorbed" oxygen species. Neither superoxide ions O(2)(-), nor charged atomic oxygen O,(-) nor peroxide ions O(2)(2-) have been observed on SnO(2) under the real working conditions of sensors. Moreover, several findings show that the superoxide ion does not undergo transformations into charged atomic oxygen at the surface, and represents a dead-end form of low-temperature oxygen adsorption on reduced metal oxide.

Intravenous ketamine is as effective as midazolam/fentanyl for procedural sedation and analgesia in the emergency department.

Science.gov (United States)

Jamal, S M; Fathil, S M; Nidzwani, M M; Ismail, A K; Yatim, F M

2011-08-01

The study compared the effectiveness of ketamine and midazolam/fentanyl as procedural sedation and analgesia agents for reduction of fractures and dislocated joints. Forty-one adult patients were enrolled by convenience sampling. They were randomized to receive ketamine or midazolam/fentanyl. Depth of sedation, pain score, procedural outcome and memory of the procedure were documented. The ketamine group had deeper sedation, but there was no statistical difference in other variables between the two groups. Three patients in the midazolam/fentanyl group had oxygen desaturation. More adverse effects were associated with ketamine. Intravenous ketamine is as effective as midazolam/fentanyl for procedural sedation.

Knock Resistance and Fine Particle Emissions for Several Biomass-Derived Oxygenates in a Direct-Injection Spark-Ignition Engine

Energy Technology Data Exchange (ETDEWEB)

Ratcliff, Matthew A.; Burton, Jonathan; Sindler, Petr; Christensen, Earl; Fouts, Lisa; Chupka, Gina M.; McCormick, Robert L.

2016-04-01

Several high octane number oxygenates that could be derived from biomass were blended with gasoline and examined for performance properties and their impact on knock resistance and fine particle emissions in a single cylinder direct-injection spark-ignition engine. The oxygenates included ethanol, isobutanol, anisole, 4-methylanisole, 2-phenylethanol, 2,5-dimethyl furan, and 2,4-xylenol. These were blended into a summertime blendstock for oxygenate blending at levels ranging from 10 to 50 percent by volume. The base gasoline, its blends with p-xylene and p-cymene, and high-octane racing gasoline were tested as controls. Relevant gasoline properties including research octane number (RON), motor octane number, distillation curve, and vapor pressure were measured. Detailed hydrocarbon analysis was used to estimate heat of vaporization and particulate matter index (PMI). Experiments were conducted to measure knock-limited spark advance and particulate matter (PM) emissions. The results show a range of knock resistances that correlate well with RON. Molecules with relatively low boiling point and high vapor pressure had little effect on PM emissions. In contrast, the aromatic oxygenates caused significant increases in PM emissions (factors of 2 to 5) relative to the base gasoline. Thus, any effect of their oxygen atom on increasing local air-fuel ratio was outweighed by their low vapor pressure and high double-bond equivalent values. For most fuels and oxygenate blend components, PMI was a good predictor of PM emissions. However, the high boiling point, low vapor pressure oxygenates 2-phenylethanol and 2,4-xylenol produced lower PM emissions than predicted by PMI. This was likely because they did not fully evaporate and combust, and instead were swept into the lube oil.

Oxygen mobility in alkali feldspars; Etude de la mobilite de l'oxygene dans les feldspaths alcalins

Energy Technology Data Exchange (ETDEWEB)

Merigoux, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1968-03-15

The oxygen mobility is shown from oxygen atoms exchange between potassic and sodic feldspars and 18 oxygen enriched water. Exchanges are carried out in autoclaves between 400 and 800 deg. C under a water pressure between 300 and 800 bars. The oxygen is extracted from silicate by a ClF{sub 3} attack. Two distinct mechanisms may be found. The first one is auto-diffusion; for adularia we have: D = 9.10{sup -7} exp(-32000/RT) (cm{sup 2}.s{sup -1}), for albite: D 4.5.10{sup -5} exp(-37000/RT) (cm{sup 2}.s{sup -1}). The second one, more rapid, is associated with alkali atoms exchanges. These results are applied to the order-disorder problem in feldspars and to the oxygen geochemistry. (author) [French] La mobilite de l'oxygene est mise en evidence a partir d'echanges d'atomes d'oxygene entre des feldspaths potassiques et sodiques en presence d'une eau enrichie en oxygene 18. Les echanges sont effectues en autoclave entre 400 et 800 deg. C sous des pressions de vapeur d'eau comprises entre 300 et 800 bars. L'oxygene est extrait du silicate par attaque au ClF{sub 3}. Deux mecanismes, bien distincts, peuvent se rencontrer. Le premier correspond a l'autodiffusion de l'oxygene; dans le domaine etudie on trouve pour l'adulaire: D = 9,10{sup -7} exp(-32000/RT) (cm{sup 2}.s{sup -1}), et pour l'albite: D 4,5.10{sup -5} exp(-37000/RT) (cm{sup 2}.s{sup -1}). Le second, beaucoup plus rapide, est associe a l'echange des atomes alcalins avec la solution. Ces resultats sont appliques au probleme du passage ordre-desordre dans les feldspaths et a la geochimie de l'oxygene. (auteur)

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.

Modification of Low Refractive Index Polycarbonate for High Refractive Index Applications

Directory of Open Access Journals (Sweden)

Gunjan Suri

2009-01-01

Full Text Available Polycarbonates and polythiourethanes are the most popular materials in use today, for optical applications. Polycarbonates are of two types which fall in the category of low refractive index and medium refractive index. The present paper describes the conversion of low refractive index polycarbonates into high refractive index material by the use of a high refractive index monomer, polythiol, as an additive. Novel polycarbonates, where the properties of refractive index and Abbe number can be tailor made, have been obtained. Thermal studies and refractive index determination indicate the formation of a new polymer with improved properties and suitable for optical applications.

Engineering High-Energy Interfacial Structures for High-Performance Oxygen-Involving Electrocatalysis.

Science.gov (United States)

Guo, Chunxian; Zheng, Yao; Ran, Jingrun; Xie, Fangxi; Jaroniec, Mietek; Qiao, Shi-Zhang

2017-07-10

Engineering high-energy interfacial structures for high-performance electrocatalysis is achieved by chemical coupling of active CoO nanoclusters and high-index facet Mn 3 O 4 nano-octahedrons (hi-Mn 3 O 4 ). A thorough characterization, including synchrotron-based near edge X-ray absorption fine structure, reveals that strong interactions between both components promote the formation of high-energy interfacial Mn-O-Co species and high oxidation state CoO, from which electrons are drawn by Mn III -O present in hi-Mn 3 O 4 . The CoO/hi-Mn 3 O 4 demonstrates an excellent catalytic performance over the conventional metal oxide-based electrocatalysts, which is reflected by 1.2 times higher oxygen evolution reaction (OER) activity than that of Ru/C and a comparable oxygen reduction reaction (ORR) activity to that of Pt/C as well as a better stability than that of Ru/C (95 % vs. 81 % retained OER activity) and Pt/C (92 % vs. 78 % retained ORR activity after 10 h running) in alkaline electrolyte. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Incorporation of oxygen into abscisic acid and phaseic acid for molecular oxygen

International Nuclear Information System (INIS)

Creelman, R.A.; Zeevaart, J.A.D.

1984-01-01

Abscisic acid accumulates in detached, wilted leaves of Xanthium strumariu. When these leaves are subsequently rehydrated, phaseic acid, a catabolite of abscisic acid, accumulates. Analysis by gas chromatography-mass spectrometry of phaseic acid isolated from stressed and subsequently rehydrated leaves placed in an atmosphere containing 20% 18 O 2 and 80% N 2 indicates that one atom of 18 O is incorporated in the 6'-hydroxymethyl group of phaseic acid. This suggests that the enzyme that converts abscisic acid to phaseic acid is an oxygenase. Analysis by gas chromatography-mass spectrometry of abscisic acid isolated from stressed leaves kept in an atmosphere containing 18 O 2 indicates that one atom of 18 O is presented in the carboxyl group of abscisic acid. Thus, when abscisic acid accumulates in water-streesed leaves, only one of the four oxygens present in the abscisic acid molecule is derived from molecular oxygen. This suggest that either (a) the oxygen present in the 1'-, 4'-, and one of the two oxygens at the 1-position of abscisic acid arise from water, or (b) there exists a stored precursor with oxygen atoms already present in the 1'- and 4'-positions of abscisic acid which is converted to abscisic acid under conditions of water stress. 17 references, 2 figures, 1 tables

Incorporation of oxygen into abscisic Acid and phaseic Acid from molecular oxygen.

Science.gov (United States)

Creelman, R A; Zeevaart, J A

1984-05-01

Abscisic acid accumulates in detached, wilted leaves of Xanthium strumarium. When these leaves are subsequently rehydrated, phaseic acid, a catabolite of abscisic acid, accumulates. Analysis by gas chromatography-mass spectrometry of phaseic acid isolated from stressed and subsequently rehydrated leaves placed in an atmosphere containing 20% (18)O(2) and 80% N(2) indicates that one atom of (18)O is incorporated in the 6'-hydroxymethyl group of phaseic acid. This suggests that the enzyme that converts abscisic acid to phaseic acid is an oxygenase.Analysis by gas chromatography-mass spectrometry of abscisic acid isolated from stressed leaves kept in an atmosphere containing (18)O(2) indicates that one atom of (18)O is present in the carboxyl group of abscisic acid. Thus, when abscisic acid accumulates in water-stressed leaves, only one of the four oxygens present in the abscisic acid molecule is derived from molecular oxygen. This suggests that either (a) the oxygen present in the 1'-, 4'-, and one of the two oxygens at the 1-position of abscisic acid arise from water, or (b) there exists a stored precursor with oxygen atoms already present in the 1'- and 4'-positions of abscisic acid which is converted to abscisic acid under conditions of water stress.

Oxygen dependency of porfiromycin cytotoxicity

International Nuclear Information System (INIS)

Marshall, R.S.; Rauth, A.M.

1987-01-01

The authors determined the oxygen dependency of toxicity for the bioreductive alkylating agents mitomycin C (MMC) and porfiromycin (PM) to investigate whether the toxicities of these agents increase in the range of oxygen tensions over which cells become increasingly radioresistant. In the present work the oxygen dependency of PM in CHO cells was determined by assaying survival as a function of time of exposure to 1.0 μg/ml PM under various known levels of oxygen. While PM demonstrated preferential hypoxic cell toxicity, aerobic cell survival was reduced ten-fold after five hours of exposure. Conversely, PM toxicity after a five hour hypoxic exposure to <0.001% oxygen appeared to be greater than that observed for similar MMC exposures, suggesting that PM may be more selective than MMC in killing hypoxic rather than aerobic cells. The authors are currently investigating this preferential toxicity in two human cell lines, one of which is resistant to these agents. At present, these observations suggest that PM may be more effective than MMC at destroying tumour cells in regions of intermediate and low oxygen tensions which may survive radiotherapy, though the range of oxygen tensions which mediate toxicity is similar for both agents

Clinical Factors Associated with the Non-Operative Airway Management of Patients with Robin Sequence

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Frank P. Albino

2016-11-01

Full Text Available BackgroundThe indications for surgical airway management in patients with Robin sequence (RS and severe airway obstruction have not been well defined. While certain patients with RS clearly require surgical airway intervention and other patients just as clearly can be managed with conservative measures alone, a significant proportion of patients with RS present with a more confusing and ambiguous clinical course. The purpose of this study was to describe the clinical features and objective findings of patients with RS whose airways were successfully managed without surgical intervention.MethodsThe authors retrospectively reviewed the medical charts of infants with RS evaluated for potential surgical airway management between 1994 and 2014. Patients who were successfully managed without surgical intervention were included. Patient demographics, nutritional and respiratory status, laboratory values, and polysomnography (PSG findings were recorded.ResultsThirty-two infants met the inclusion criteria. The average hospital stay was 16.8 days (range, 5–70 days. Oxygen desaturation (<70% by pulse oximetry occurred in the majority of patients and was managed with temporary oxygen supplementation by nasal cannula (59% or endotracheal intubation (31%. Seventy-five percent of patients required a temporary nasogastric tube for nutritional support, and a gastrostomy tube placed was placed in 9%. All patients continued to gain weight following the implementation of these conservative measures. PSG data (n=26 demonstrated mild to moderate obstruction, a mean apneahypopnea index (AHI of 19.2±5.3 events/hour, and an oxygen saturation level <90% during only 4% of the total sleep time.ConclusionsNonsurgical airway management was successful in patients who demonstrated consistent weight gain and mild to moderate obstruction on PSG, with a mean AHI of <20 events/hour.

Biogeochemistry: Oxygen burrowed away

NARCIS (Netherlands)

Meysman, F.J.R.

2014-01-01

Multicellular animals probably evolved at the seafloor after a rise in oceanic oxygen levels. Biogeochemical model simulations suggest that as these animals started to rework the seafloor, they triggered a negative feedback that reduced global oxygen.

Vertical and temporal dynamics of phytoplanktonic associations and the application of index assembly in tropical semi-arid eutrophic reservoir, northeastern Brazil

Directory of Open Access Journals (Sweden)

Pryscila Cynara Soares Vieira

2015-03-01

Full Text Available AimTo determine the composition and biomass of functional groups around the vertical and temporal gradient correlated with environmental conditions and apply the index Q in a water-supply reservoir.MethodsWater samples were collected monthly (n = 92 between 2009 and 2011 in two points of the dam for physicochemical and biological analysis.ResultsThe pH, dissolved oxygen and water temperature showed significant differences between the photic and aphotic zones (p<0.05. The vertical variation of dissolved oxygen and water temperature, showed a profile of stratification. The phytoplankton community was represented by 11 functional groups: S1, M, H1, Lo, P, F, SN, J, W2, MP and R.ConclusionsThe vertical variations were less pronounced than the temporal variations in the phytoplankton community. The Q index pointed out poor water quality, corresponding to the current state of eutrophication in the reservoir and it was sensitive to responsive to environmental and hydrodynamic changes in these systems, demonstrating to be an appropriate tool for monitoring and evaluating the quality of water in tropical semi-arid reservoirs.

Oxygen as a factor in eukaryote evolution - Some effects of low levels of oxygen on Saccharomyces cerevisiae

Science.gov (United States)

Jahnke, L.; Klein, H. P.

1979-01-01

A comparative study of the effects of varying levels of oxygen on some of the metabolic functions of the primitive eukaryote, Saccharomyces cerevisiae, has shown that these cells are responsive to very low levels of oxygen: the level of palmitoyl-Co A desaturase was greatly enhanced by only 0.03 vol % oxygen. Similarly, an acetyl-CoA synthetase associated predominantly with anaerobic growth was stimulated by as little as 0.1% oxygen, while an isoenzyme correlated with aerobic growth was maximally active at much higher oxygen levels (greater than 1%). Closely following this latter pattern were three mitochondrial enzymes that attained maximal activity only under atmospheric levels of oxygen.

Oxygen concentration inside a functioning photosynthetic cell.

Science.gov (United States)

Kihara, Shigeharu; Hartzler, Daniel A; Savikhin, Sergei

2014-05-06

The excess oxygen concentration in the photosynthetic membranes of functioning oxygenic photosynthetic cells was estimated using classical diffusion theory combined with experimental data on oxygen production rates of cyanobacterial cells. The excess oxygen concentration within the plesiomorphic cyanobacterium Gloeobactor violaceus is only 0.025 μM, or four orders of magnitude lower than the oxygen concentration in air-saturated water. Such a low concentration suggests that the first oxygenic photosynthetic bacteria in solitary form could have evolved ∼2.8 billion years ago without special mechanisms to protect them against reactive oxygen species. These mechanisms instead could have been developed during the following ∼500 million years while the oxygen level in the Earth's atmosphere was slowly rising. Excess oxygen concentrations within individual cells of the apomorphic cyanobacteria Synechocystis and Synechococcus are 0.064 and 0.25 μM, respectively. These numbers suggest that intramembrane and intracellular proteins in isolated oxygenic photosynthetic cells are not subjected to excessively high oxygen levels. The situation is different for closely packed colonies of photosynthetic cells. Calculations show that the excess concentration within colonies that are ∼40 μm or larger in diameter can be comparable to the oxygen concentration in air-saturated water, suggesting that species forming colonies require protection against reactive oxygen species even in the absence of oxygen in the surrounding atmosphere. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Oxygen Concentration Inside a Functioning Photosynthetic Cell

OpenAIRE

Kihara, Shigeharu; Hartzler, Daniel A.; Savikhin, Sergei

2014-01-01

The excess oxygen concentration in the photosynthetic membranes of functioning oxygenic photosynthetic cells was estimated using classical diffusion theory combined with experimental data on oxygen production rates of cyanobacterial cells. The excess oxygen concentration within the plesiomorphic cyanobacterium Gloeobactor violaceus is only 0.025 μM, or four orders of magnitude lower than the oxygen concentration in air-saturated water. Such a low concentration suggests that the first oxygenic...

Sleep disordered breathing and autonomic function in overweight and obese children and adolescents

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Annelies Van Eyck

2016-12-01

Full Text Available Obstructive sleep apnoea (OSA, common in children with obesity, is associated with cardiovascular morbidity. Autonomic dysfunction has been suggested to be a key player in the development of these complications. We investigated the relationship between obesity, OSA and sympathetic activity in children. 191 children with obesity were included and distributed into two groups: 131 controls and 60 with OSA. Beat-to-beat RR interval data were extracted from polysomnography for heart rate variability analysis. Urinary free cortisol levels were determined. Urinary free cortisol did not differ between groups and was not associated with OSA, independent of the level of obesity. Differences in heart rate variability measures were found: mean RR interval decreased with OSA, while low/high-frequency band ratio and mean heart rate increased with OSA. Heart rate variability measures correlated with OSA, independent of obesity parameters and age: oxygen desaturation index correlated with mean heart rate (r=0.19, p=0.009 and mean RR interval (r= −0.18, p=0.02, while high-frequency bands and low/high-frequency band ratio correlated with arterial oxygen saturation measured by pulse oximetry (SpO2 (r= −0.20, p=0.008 and r= −0.16, p=0.04 and SpO2 nadir (r=0.23, p=0.003 and r= −0.19, p=0.02. These results suggest that sympathetic heart activity is increased in children with obesity and OSA. Measures of hypoxia were related to increased sympathetic tone, suggesting that intermittent hypoxia is involved in autonomic dysfunction.

Hyperbaric Oxygen Therapy as an Adjuvant Therapy for Comprehensive Treatment of Fournier's Gangrene.

Science.gov (United States)

Li, Chao; Zhou, Xu; Liu, Long-Fei; Qi, Fan; Chen, Jin-Bo; Zu, Xiong-Bing

2015-01-01

To compare simple conventional treatment with the addition of hyperbaric oxygen therapy (HBOT) to conventional therapies in the treatment of Fournier's gangrene (FG). A retrospective study of clinical data was performed by reviewing 28 cases of FG from January 2004 to December 2013 at Xiangya Hospital, Central South University. Among them, 12 patients were treated with the conventional therapy (non-HBOT group) and the other 16 cases were combined with hyperbaric oxygen therapy besides conventional therapy (HBOT group). All patients were followed up for 2 months to assess the therapeutic effect. The analyzed data included age, Fournier gangrene severity index (FGSI) score, number of surgical debridement, indwelling drainage tube time, length of stay (LOS), effective time, and curative time. The mortality rate was lower in the HBOT group at 12.5% (2/16) compared to the non-HBOT group, which was 33.3% (4/12). The difference in the number of surgical debridement, indwelling drainage tube time, and curative time between were significantly lower in the HBOT group compared to the non-HBOT group. Our preliminary research suggests that the effect of combining hyperbaric oxygen therapy with conventional therapy offers considerable advantage in the management of Fournier's gangrene. Multicenter studies with a larger sample size are required to confirm these observations. © 2015 S. Karger AG, Basel.

Theory of oxygen isotope exchange

NARCIS (Netherlands)

den Otter, M.W.; Boukamp, Bernard A.; Bouwmeester, Henricus J.M.

2001-01-01

Transients for oxygen molecular mass numbers 32, 34 and 36 are derived which can be used for the interpretation of oxygen isotope exchange data based on measurement of concentrations of 16O2, 16O18O and 18O2 in the gas phase. Key parameters in the theory are the rate at which oxygen molecules are

Oxygen Effects in Anaerobic Digestion

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Deshai Botheju

2009-10-01

Full Text Available Interaction of free oxygen in bio-gasification is a sparsely studied area, apart from the common argument of oxygen being toxic and inhibitory for anaerobic micro-cultures. Some studies have, however, revealed increased solubilisation of organic matter in the presence of some free oxygen in anaerobic digestion. This article analyses these counterbalancing phenomena with a mathematical modelling approach using the widely accepted biochemical model ADM 1. Aerobic oxidation of soluble carbon and inhibition of obligatory anaerobic organisms are modelled using standard saturation type kinetics. Biomass dependent first order hydrolysis kinetics is used to relate the increased hydrolysis rate with oxygen induced increase in biomass growth. The amended model, ADM 1-Ox (oxygen, has 25 state variables and 22 biochemical processes, presented in matrix form. The computer aided simulation tool AQUASIM 2.1 is used to simulate the developed model. Simulation predictions are evaluated against experimental data obtained using a laboratory batch test array comprising miniature anaerobic bio-reactors of 100 ml total volume each, operated under different initial air headspaces giving rise to the different oxygen loading conditions. The reactors were initially fed with a glucose solution and incubated at 35 Celsius, for 563 hours. Under the oxygen load conditions of 22, 44 and 88 mg/L, the ADM1-Ox model simulations predicted the experimental methane potentials quite adequately. Both the experimental data and the simulations suggest a linear reduction of methane potential with respect to the increase in oxygen load within this range.

Single Cell Oxygen Mapping (SCOM) by Scanning Electrochemical Microscopy Uncovers Heterogeneous Intracellular Oxygen Consumption

OpenAIRE

Santos, Carla Santana; Kowaltowski, Alicia J.; Bertotti, Mauro

2017-01-01

We developed a highly sensitive oxygen consumption scanning microscopy system using platinized platinum disc microelectrodes. The system is capable of reliably detecting single-cell respiration, responding to classical regulators of mitochondrial oxygen consumption activity as expected. Comparisons with commercial multi-cell oxygen detection systems show that the system has comparable errors (if not smaller), with the advantage of being able to monitor inter and intra-cell heterogeneity in ox...