Anesthetic-induced changes in cardiovascular and small intestinal responses to endotoxin in the rat.

The influence of anesthesia on endotoxin shock patterns in the rat was examined. Blood pressure, heart rate, arterial blood gases, glucose, lactate, and pathology of the small intestine were measured before and after endotoxin (40 mg/kg) challenge in male Sprague-Dawley rats. The three groups studied were: (1) enflurane anesthetized (N = 10), (2) ketamine anesthetized (N = 10), and (3) awake and unrestrained (N = 13). Measurements were made during 30 min prior to endotoxin injection (IV) and for 240 min afterward. Reflex tachycardia, which occurred in the awake group simultaneously with the initial endotoxin-induced hypotension, was not present during either enflurane or ketamine anesthesia. Significantly less gross intestinal pathology was found at 4 hr after endotoxin in the anesthetized groups compared to the awake group. These results suggest that the response of the sympathoadrenal system to the hypotension following endotoxin may be blunted in the anesthetized animal.