Abstract
We compared the effects of isoflurane and halothane=induced hypotension on carbohydrate metabolism in dogs. Eighteen mongrel dogs were anesthtized with pentobarbital intravenously and randomly divided into two groups : a halothane group (n=8), which received 0.9% halothane in oxygen, and an isoflurane group (n=8), which received 1.3% isoflurane in oxygen. The inspired concentration of halothane or isoflurane were increased to decrease mean arterial pressure to 60mmHg, which was maintained for 60 minutes. Hemodynamic parameters and arterial blood gases were measured and blood samples for determination of level of glucose and lactic acid were collected before, during, and after hypotension. Blood glucose levels in the both groups remained unchanged throughout the observation period. Lactic acid increased significantly during and after hypotension in the halothane group : however, it did not change significantly in the isoflurane group. Arterial pH, PaCO2, and base excess in the isoflurane group remained unchanged hroughout the observation period. Base excess in the halothane group decreased significantly during and after induced hypotension. In both groups, PaCO2 decreased significantly during hypotension but returnred to the baseline value, after hypo. tension. These results suggest that carbohydrate metabolism is affected less by isoflurane=induced hypotension than by halothane-induced hypotension. We conclude that isoflurane preserves peripheral circulation during profound hypotension and suggest that isoflurane-induced hypotension can be employed safely in clinical situations.
