Hemodynamic alterations after 30 minutes of pentobarbital sodium anesthesia in dogs

Abstract

In order to study the effects of pentobarbital sodium (Nembutal) anesthesia on the cardiovascular system, mean arterial pressure, cardiac output, stroke volume, total peripheral resistance, plasma and blood volumes, and the circulation time were measured in 20 board-trained unanesthetized dogs and in 20 animals 30 min subsequent to anesthetization with 30 mg/kg Nembutal. The mean arterial pressure, heart rate, cardiac output, and peripheral resistance were all markedly increased ( P < .001) in the anesthetized dogs, while the average blood volume in this group was significantly decreased, presumably due to a decrement in the circulating red cell mass. As might be expected from these results, the circulation time was decreased ( P < .001) in the anesthetized group. These data indicate that pentobarbital sodium exerts a profound influence on the cardiovascular system and serve as a reminder that the ubiquity of Nembutal anesthesia in experimental medicine mandates that the investigator appreciate the altered cardiovascular system with which he is working.