The effects of pentobarbitone sodium on the carbon dioxide response and production, and oxygen consumption of the rabbit

Abstract The effect of intravenous doses of pentobarbitone sodium on the ventilatory response to CO2, CO2 production and O2 consumption were investigated in the rabbit. Pentobarbitone sodium depressed the ventilatory response to CO2, but the time course of this effect showed a biphasic character whereas depression of unchallenged minute volume did not. O2 consumption and CO2 production were reduced by pentobarbitone, but although the degree and duration of the depression increased with increasing dose, the values returned to control values before depression of respiratory minute volume and response to CO2. The possibility that these results may explain the lack of progressive depression of respiratory minute volume with increasing dose of barbiturate, previously reported by the authors, is discussed.