[Effects of pentobarbital on coronary and cerebral circulation and metabolism in dogs subjected to hemorrhage].

Mongrel dogs were divided into a neuroleptanesthesia group (n = 10) and a pentobarbital group (neuroleptanesthesia plus pentobarbital; n = 10). The dogs were subjected to stepwise hemorrhage increasing from 30 to 40 and 50 ml.kg-1. In the neuroleptanesthesia group, mean arterial pressure, and cerebral and coronary blood flow decreased. Furthermore the oxygen and hydrogen ion balance in both the brain and the myocardium was aggravated, even at 30 ml.kg-1 of hemorrhage. Compared to the neuroleptanesthesia group, mean arterial pressure, and cerebral and coronary blood flow showed a greater decrease, cerebral oxygen consumption was lower, and the brain and myocardial metabolism worsened similarly at equivalent hemorrhage in the pentobarbital group. These results suggest that pentobarbital in combination with neuroleptanesthesia reduces cerebral oxygen consumption, but does not improve cerebral metabolism in the state of acute hemorrhage due to simultaneous induction of severe circulatory depression.