EFFECTS IN DOGS OF HYPERVENTILATION AND HYPOTHERMIA ON BODY OXYGEN STORES BY

Six anaesthetized, paralyzed, hypothermic (30 ° C) dogs were hyperventilated for 2 hours. During the final 30 minutes, die inspired mixture was altered from oxygen to air. The rates at which alveolar and arterial oxygen concentrations approached their new steady state values were represented by the half-times (t£) of 0.19 and 0.26 minutes, respec-tively. The turnover rate in venous blood oxygen content proceeded at a considerably slower rate, t^=0.90 minutes. The close agreement of results during hypothermia with results obtained during normothermia indicates that hypothermia per se has no signifi-cant effect upon oxygen turnover rate. When the metabolic requirement for oxygen temporarily exceeds the oxygen supplied by ventilation, the immediate oxygen deficit is paid by the oxygen stored in the body. This oxygen reservoir is limited and scarcely contains enough oxygen to supply the body for 5 minutes after gaseous interchange in the lungs has stopped