The relationship between the arterial oxygen saturation and the cardiovascular response to induced anoxemia in normal young adults.

AT THE present time the most widely used method of studying the effect of induced anoxemia on the cardiovascular system consists of giving the subjects low oxygen gas (usually 10 per cent) inhalation for approximately twenty minutes and making observations during this period. In previous communications1'the variability of the degree of anoxemia, as measured by the blood arterial oxygen saturation, during inhalation of a gas of fixed low oxygen concentration was pointed out. The physiologic importance of standardizing the induced anoxemia test of cardiovascular function according to the level of the arterial oxygen saturation was discussed and a method of inducing and maintaining a constant degree of anoxemia by administering a gas of variable oxygen concentration was described. In one of these reports' the nature of the cardiovascular response of a small group of young men at levels of 85, 80, and 75 per cent arterial oxygen saturation was presented. It is the purpose of this report to give a detailed description and analysis of the effect of anoxemia upon the heart rate, blood pressure, and electrocardiogram at levels of 80, 75, and 70 per cent arterial saturation in a substantial number of normal young adults.