Circulation in Dogs After Respiratory Arrest Induced by Curare

Abstract

After inducing respiratory arrest in dogs with an intravenous indection of d-tubocurarine, circulatory variables were studied during 15-minute periods of "apneic oxygenation" and "apneic hypoxia." "Apneic oxygenation" is defined as a period of respiratory arrest following nearly complete denitrogenation of the animal during which the trachea is connected to a reservoir containing 100% O2. "Apneic hypoxia" is defined as a period of respiratory arrest during which the trachea is connected to room air. In both periods, an increase in pressures in the systemic arteries and the pulmonary vessels, as well as a marked bradycardia, was seen. A rise in cardiac output could account for the elevated pressures. Mechanisms responsible for the bradycardia are not clear.