Blood gas and neurological responses to inhalation of oxygen at 3 atmospheres.

Abstract

SummaryArterial blood gas tensions, pulse and blood pressure were monitored repeatedly in 7 normal young men while they breathed 99% oxygen at 3 atmospheres in a hyperbaric chamber for periods of up to 3 hours. There was evidence that 6 of these subjects hyperventilated during the exposure. Arterial Pco2 began to fall during the first 5 minutes of exposure and continued to decline to 35 mm Hg during the first 90 minutes. It tended to remain constant during the rest of the exposure. Arterial Po2 rose to 2000 mm Hg during the first 5 minutes of exposure and remained at this level. The pulse rate fell by 25% and remained at this level for at least 2 hours when it began to increase. Blood pressure was constant for the first 2 hours of exposure and began to rise at the same time as the pulse. Loss of peripheral vision as well as subjective signs of oxygen intoxication (dizziness, nausea, etc.) began to appear during the third hour of exposure but no convulsions were produced.