Canadian Journal of Anesthesia, Vol 9, 36-41, Copyright © 1962 by Canadian Anesthesiologists' Society

The Effect of SA 97, Perphenazine, and Hydroxyzine on Epinephrine-Induced Cardiac Arrhythmias during Methoxyflurane Anaesthesia in Dogs

¹ Department of Anesthesiology, Upstate Medical Center, Syracuse, New York

Forty-one acute experiments were done on 11 mongrel dogs after 25 minutes of 1 per cent methoxyflurane-oxygen anaesthesia to determine the severity of cardiac arrhythmias produced by an epinephrine challenge and to evaluate the efficacy of SA 97 (an antihistaminic) as a protectant. Perphenazine and hydroxyzine were also used as a comparison with SA 97. Pulmonary ventilation was augmented during anaesthesia to eliminate hypoxia and hypercarbia during the experiments. The doses selected for each agent were such that severe hypotension would not be expected to occur prior to the epinephrine challenge.

The arrhythmias provoked by an epinephrine challenge during methoxyflurane anaesthesia were less severe than those seen in similar experiments with trichlorethylene, cyclopropane, and halothane, but were similar to those during anaesthesia with halothane-ether azeotrope and light chloroform.

Perphenazine in a dose of 0.25 mg./kg. was more effective than hydroxyzine (1 mg./kg.) and SA 97 (1 mg./kg.) in reducing cardiac arrhythmias produced by an epinephrine challenge. However, none of the drugs completely eliminated serious ventricular arrhythmias. Therefore, epinephrine should not be used during anaesthesia with methoxyflurane, unless a small amount is injected subcutaneously in a very dilute solution (less than 1:200,000).