Background Cardiac surgery is widely used in the treatment of cardiovascular diseases. However, several complications can be observed during the postoperative period. Positive end expiratory pressure (PEEP) improves gas exchange, but it might be related to decreased cardiac output and possible impairment of tissue oxygenation. The aim of this study was to investigate the hemodynamic effects and...

The oxygenation state of myoglobin and the redox state of cytochrome c provide information on the[Formula: see text] in the cytosol and mitochondria, respectively. An optical "window" from ∼540 to 585 nm was found in the pig heart in vivo that permitted the monitoring of myoglobin and cytochrome c without interference from Hb oxygenation or blood volume. Scanning reflectance spectroscopy was pe...

Heterogeneity in the distribution of both blood flow (Q̇) and O2 consumption (V̇O2) has not been assessed by near-infrared spectroscopy in exercising normal human muscle. We used near-infrared spectroscopy to measure the regional distribution of Q̇ and V̇O2 in six trained cyclists at rest and during constant-load exercise (unloaded pedaling, 20%, 50%, and 80% of peak Watts) in both normoxia and hyp...

Arai, Andrew E., Claudia E. Kasserra, Paul R. Territo, Amir H. Gandjbakhche, and Robert S. Balaban. Myocardial oxygenation in vivo: optical spectroscopy of cytoplasmic myoglobin and mitochondrial cytochromes. Am. J. Physiol. 277 (Heart Circ. Physiol. 46): H683–H697, 1999.— The oxygenation state of myoglobin and the redox state of cytochrome c provide information on the PO2 in the cytosol and mi...

In these experiments we have studied three factors that affect placental O2 transfer. The fetal artery of an isolated cotyledon of the sheep placenta (or one of the umbical arteries in flow studies in rabbits) was perfused in situ with blood of varying PO2 and at different flow rates while the ewe was administered varying inspired O2 concentrations. Measurements were made of the PO2 of inflowin...

We hypothesized that breathing hypoxic, hypercapnic, and CO-containing gases together reduces maximal aerobic capacity (Vo2max) as the sum of each gas' individual effect on Vo2max. To test this hypothesis, goats breathed combinations of inspired O2 fraction (FiO2) of 0.06-0.21 and inspired CO2 fraction of 0.00 or 0.05, with and without inspired CO that elevated carboxyhemoglobin fraction (FHbCO...

Although hypoxia tolerance in heterothermic mammals is well established, it is unclear whether the adaptive significance stems from hypoxia or other cellular challenge associated with euthermy, hibernation, or arousal. In the present study, blood gases, hemoglobin O2 saturation (S(O2), and indexes of cellular and physiological stress were measured during hibernation and euthermy and after arous...

INTRODUCTION Improving tissue oxygenation is one of most important tasks in management of low cardiac output. Central venous oxygen saturation (ScvO2) and lactate are established criteria for monitoring the adequacy of tissue oxygenation. The venous-to-arterial carbon dioxide difference [P(v-a)CO2] is inversely associated with cardiac output. AIM To study the use of P(v-a)CO2/C(a-v)O2 ratio a...

PURPOSE We have recently reported that many healthy habitually active women experience exercise induced arterial hypoxemia (EIAH). We questioned whether EIAH affected VO2max in this population and whether the effect was similar to that reported in men. METHODS Twenty-five healthy young women with widely varying fitness levels (VO2max, 56.7 +/- 1.5 mL x kg(-1) x min(-1); range: 41-70 mL x kg(-...

Erythrocytic 2,3-diphosphoglycerate (2,3-DPG), in response to carbon monoxide (CO) hypoxemia, was studied in 12 rabbits exposed to 250 ppm CO for 3 hours. Each animal served as its own control. Individual determinations of carboxyhemoglobin, arterial oxygen content, oxygen saturation, and 2,3-DPG were made before and immediately after exposures to both CO and normal air. After CO inhalation, th...