EFFECTS OF 100-PERCENT O-2, EXPOSURE ON HYPOXIC VENTILATORY RESPONSE

Comparison of the slope of progressive isocapnic hypoxia obtained with and without prior O-2 exposure (termed + and -O-2 runs, respectively) placed our subjects into two groups. Positive responders had a signif icantly lower slope in -O-2 runs compared with similar runs in negativ e responders, but they also improved hypoxic ventilatory response (HVR ) significantly after O-2 exposure. Negative responders had a high -O- 2 slope that did not alter significantly after O-2 exposure. We conclu de that ambient air hypoxic depression is active in positive responder s who are O-2 sensitive.