EFFECTS OF PENTOBARBITAL AND MEPERIDINE ON CANINE CEREBRAL AND TOTAL OXYGEN CONSUMPTION RATES

The individual effects of two premedicant drugs, pentobarbital and meperidine, on both total-body oxygen consumption ( Vo2 ) and cerebral oxygen consumption ( CMRo2 ) rates were studied in dogs during light halothane anaesthesia. Vo2 was measured by means of a modified closed-circuit spirometry apparatus. CMRo2 was calculated from the difference between arterial and sagittal-sinus oxygen content and from the directly measured cerebral blood flow. Pentobarbital decreased Vo2 by 7 per cent and CMRo2 by 10 per cent. Meperidine had no effect on Vo2, but decreased CMR02 by 13 per cent. These findings are discussed in relation to previous reports of the effects of preanaesthetic medication on Vo2 in man and current concepts of the relationship between cerebral metabolism and function. © 1969 Canadian Anesthesiologists.