PHYSIOLOGIC EFFECTS OF EXPOSURE TO INCREASED OXYGEN TENSION AT 5 P.S.I.A.,

Data were obtained during two 14-day experiments in the USAF SAM two-man space cabin simulator relative to the physiologic factors in atmosphere selection. Both experiments were conducted at a simulated altitude of 27,000 feet 258 mm. Hg and a PO2 of 243 mm. Hg. Emphasis was placed on arterial and alveolar PO2 and PCO2, chest x-rays, and vital capacity, all determined at the experimental altitude and atmosphere. The atmosphere, in general, was well tolerated by all 4 test subjects. No atelectasis was made evident by x-ray or by changes in vital capacity. Although vital capacity was reduced an average of 2.9, this was not felt to be indicative of atelectasis. Arterial PO2 was slightly lowered but, again, it did not indicate a significant increase in the normal physiologic shunting of blood. Author