Epinephrine in the treatment of cardiac failure due to shunts.

Abstract

A technic for establishing a controlled aorto-pulmonary shunt in closed-chest, spontaneously breathing dogs has been developed. Wide opening of the shunt is well tolerated in some animals, but others develop acute left ventricular failure. Administration of sympathetic blocking agents may induce a failure response on opening the shunt, in an animal that previously tolerated it well. Epinephrine infusion during the control period consistently prevented cardiac failure when the shunt was widely opened. Epinephrine was also capable of reversing the failure, if rapidly infused before left ventricular systolic pressure had dropped to extremely low levels. It was also effective in countering the adverse effects of sympathetic blocking agents. The optimal rate of infusion was found to be 0.5 to 1.5 µg./Kg./min. of epinephrine hydrochloride. A constant infusion of epinephrine hydrochloride was administered to three infants with large left-to-right shunts who had failed to respond to intensive decongestive measures, and who manifested severe cardiac failure with severe pulmonary edema. Marked clinical improvement resulted, and anesthesia and surgery were well tolerated while the infusion was continued. Epinephrine should be administered with a constant infusion apparatus to avoid induction of ventricular ectopic beats due to overdosage. Its use is reserved, at present, for the management of the desperately sick infant with acute left ventricular failure due to systemic-pulmonary shunts.