Arterial CO2 tension adjustment rates following hyperventilation.

Abstract

Anesthetized, paralyzed human subjects were hyperventilated for 2 hr. At the end of this period, arterial CO2 tension, PaCO2, changed less than 1 mm in 15 min. Following a step decrease in ventilation, PaCO2 was measured serially until the change was less than 1 mm in 10 min. ie., for periods up to 70 min. An equilibrium value was not reached in the limited duration of these studies, however an estimate of this value can be made. The data are represented as the sum of 2 exponential functions, with rate constants k1 and k2 whose average values are 0.46 min.-1 and 0.030 min. -1.