Effect of pentobarbital anesthesia on hypotension after 10% hemorrhage in the dog

The effect of pentobarbital anesthesia, 30 mg.kg body wt-1, on the rapidly acting arterial pressure control system was studied on splenectomized dogs chronically instrumented with catheters for pressure measurement and hemorrhage and with a flow probe for measurement of aortic flow. The dogs were subjected to 10% hemorrhage in 30 s under conscious and anesthetized states before and after denervation of the carotid sinus nerves (CS) and/or the vagi (V). In the intact nerve condition, arterial pressure fall (delta AP) at 1-2 min after hemorrhage was 8.0 +/- 1.3 (mean +/- SE) mmHg in conscious dogs and 9.4 +/- 2.0 mmHg in dogs under anesthesia. There was no significant difference between these delta APs or other pairs of delta APs in conscious and anesthetized states at any stage of denervation. As long as the CS reflex was intact, heart rate and total peripheral resistance increased in response to hemorrhage as in the intact condition. In conclusion, the pentobarbital anesthesia had little effect on the rapidly acting arterial pressure control system as far as its capacity to restore mean arterial pressure after the brief 10% hemorrhage is concerned.