The aim of this study was to investigate the effects of short repeated apneas on breathing pattern and circulatory response in trained (underwater hockey players: UHP) and untrained (controls: CTL) subjects. The subjects performed five apneas (A1-A5) while cycling with the face immersed in thermoneutral water. Respiratory parameters were recorded 1 minute before and after each apnea and venous ...

The specific conductance (G) for O2 transfer by red blood cells (RBCs) of chicken and muscovy duck was measured using the experimental (stopped-flow) and analytical techniques (RBC model) previously applied to human RBC (Yamaguchi, Nguyen Phu, Scheid & Piiper, 1985). Avian RBCs behaved similarly to human RBCs: G values were of similar magnitude; G for O2 uptake decreased with time and increasin...

The direct and modulating effects of acidosis on catecholamine secretion in rainbow trout (Oncorhynchus mykiss) were assessed in vivo using cannulated fish and in situ using a perfused cardinal vein preparation. In situ, acidosis (a reduction in perfusate pH from 7.9 to 7.4) did not elicit catecholamine release or modulate the secretion of catecholamines evoked by the non-specific cholinergic r...

Recent interest in functional hemodynamic monitoring for the bedside assessment of cardiovascular insufficiency has heightened. Functional hemodynamic monitoring is the assessment of the dynamic interactions of hemodynamic variables in response to a defined perturbation. Accordingly, fluid responsiveness can be predicted in a quantities fashion by measuring as arterial pulse pressure variation ...

Patients with chronic obstructive pulmonary disease (COPD) frequently develop nocturnal oxygen desturation because of alveolar hypoventilation, worsening of ventilation-perfusion mismatch, and sometimes obstructive sleep apnoeas. In contrast, little is known about their oxygen status during the various activities of daily life. The aim of this study was to compare the oxygen saturation profile ...

PURPOSE Evaluation of metabolic parameters and cardiac function is important to determine the decrease in aerobic exercise capacity under hypoxic conditions. However, the variations in metabolic parameters and cardiac function and the reasons for the decrease in aerobic exercise capacity under hypoxic conditions have not been clearly explained. The purpose of this study was to compare the respo...

Many water-breathing animals have a strategy that consists of maintaining low blood PO2 values in a large range of water oxygenation level (4-40 kPa). This study examines the postprandial changes in O2 consumption, arterial blood PO2, and tissue protein synthesis in the shore crab Carcinus maenas in normoxic, O2-depleted, and O2-enriched waters to study the effects of this strategy on the O2 co...

The effects of intravenous ketamine (1 mg/kg) on cerebral cortical blood flow and O2 uptake were evaluated in 13 anesthetized, ventilated rabbits. Blood flow was measured either directly (Group 1) or by the H2 clearance method (Group 2). In those animals of Groups 1 and 2 with normal control arterial pH (pHa), ketamine produced a significant increase in cerebral cortical blood flow of 18 and 34...

OBJECTIVES Near-infrared spectroscopy monitors cerebral oxygen saturation. This parameter parallels jugular venous oxygen saturation and reflects the balance between cerebral oxygen supply and demand. Experience with near-infrared spectroscopy in univentricular physiology is limited. This study explores the relationship between cerebral oxygen saturation, jugular venous oxygen saturation, and o...

Weaver LK, Howe S, Snow GL, Deru K. Arterial and pulmonary arterial hemodynamics and oxygen delivery/extraction in normal humans exposed to hyperbaric air and oxygen. J Appl Physiol 107: 336–345, 2009. First published April 30, 2009; doi:10.1152/japplphysiol.91012.2008.— Divers and hyperbaric chamber attendants breathe hyperbaric air routinely. Hyperbaric oxygen (HBO2) is used therapeutically f...