Canadian Journal of Anesthesia, Vol 9, 437-442, Copyright © 1962 by Canadian Anesthesiologists' Society

The Cardiac Effect of Epinephrine during Anaesthesia in Hyperthyroid Dogs

¹ Department of Anesthesiology, State University of New York, Upstate Medical Center, Syracuse, N.Y.

In this study, it was assumed that a true hyperthyroid state could be produced in dogs by the oral administration of Protamone until the protein-bound iodine level in the blood was markedly elevated. Dogs made "hyperthyroid" in this way were given a standard epinephrine challenge during methoxyflurane, trifluoro-ethylvinyl ether, and thiopental – nitrous oxide anaesthesia. Ventricular fibrillation occurred more frequently and the quality and severity of arrhythmias were greater than was seen in euthyroid dogs after a similar challenge with epinephrine. Euthyroid dogs during thiopental – nitrous oxide anaesthesia were subjected to the standard epinephrine challenge. The qualitative and quantitative arrhythmias resulting were the same as previously reported with methoxyflurane and trifluoroethylvinyl ether.

These experiments suggest that the risk of cardiac arrhythmias during clinical anaesthesia in the hyperthyroid patient is probably the same with methoxyflurane, trifluoroethylvinyl ether or thiopental – nitrous oxide, and that the use of epinephrine during such anaesthesias may be as dangerous as with halothane.