Ethanol-induced lowering of arterial oxyhemoglobin saturation during hypoxia

Nine fasting, healthy, adult male volunteers were given oral carbohydrate before exposures to normoxia (PIO2 = 149 torr) and mild hypoxia (PIO2 = 98 torr). Following recovery, they were given oral ethanol before similar exposure to normoxia and mild hypoxia. Repeated measures of arterial blood and expired gases were made. Ethanol diminished respiratory gas exchange (R), causing lower alveolar and arterial oxygen pressures during normoxia and mild hypoxia and a reduction in arterial oxygen saturation from 89.9 to 87.4% during mild hypoxia. It is suggested that carbohydrates are preferable to ethanol and fats as nutrients during limited oxygen transport situations, such as high-altitude, carbon monoxide exposure, or during heavy exertion, and for patients with cardiovascular or pulmonary disease.