BACKGROUND This study investigated the effects of a prior individualized training program (TP) on the response to acute oxygen supply during exercise in chronic obstructive pulmonary disease (COPD) patients showing exercise-induced desaturation. METHODS Twenty-two COPD patients (mean [SD] FEV1 = 52.1 [3]% predicted) who desaturated on exercise participated in a TP. Exercise tolerance while br...

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 em...

To investigate the dynamics of tissue oxygen demand and supply during brain functions, we simultaneously recorded Po(2) and local cerebral blood flow (LCBF) with an oxygen microelectrode and laser Doppler flowmetry, respectively, in rat somatosensory cortex. Electrical hindlimb stimuli were applied for 1, 2, and 5 s to vary the duration of evoked cerebral metabolic rate of oxygen (CMR(O(2))). T...

The cardiorespiratory responses to an i.v. infusion of dobutamine hydrochloride were assessed in eight anaesthetized, mechanically ventilated dogs. As the rate of infusion of dobutamine was increased from 2 to 30 microgram kg-1 min-1, there was a progressive decrease in arterial pressure, pulmonary wedge pressure and arterial pH. There was a significant decrease in arterial oxygen tension at th...

To ensure that tissues are well oxygenated, oxygen supply and demand are now targets of therapy for the critically ill patient. This chapter reviews the physiologic determinants of oxygen supply, how it is threatened by respiratory or cardiac dysfunction or by hemorrhaged or anemic states, and how it can be assessed in individual patients. Activities and conditions that increase tissue oxygen d...

In eight rabbits, the common carotid artery was ligated and multiple estimations of brain surface oxygen tension performed using a seven barrelled mini-electrode. In five rabbits ligation of the carotid artery resulted in impairment of cortical oxygenation. The remaining three rabbits showed no impairment in the supply of oxygen to the cerebral cortex after carotid occlusion. In the five rabbit...

Oxygen concentrations in gelatinous egg masses of two species of opisthobranch gastropods were examined with microelectrodes. Embryos in central positions are near the limit of the oxygen supply required for development. This limit is approached despite a diffusion constant for oxygen in masses that is close to that in water. Closed-chamber respirometry shows that oxygen is consumed by masses i...

1 local terms. It is generally due to a more speci c restriction in blood supply (and therefore oxygen supply) to a speci c organ. Hypoxemia, a term commonly confused with hypoxia, refers to an ab de ciency in the concentration of oxygen in arterial blood. Anoxia refers to the complete deprivation of oxygen supply. Finally, hypercapnia is an associated state marked by an ably high level of carb...