Cardiovascular effects produced by a combination of d-tubocurarine and pancuronium in dogs.

The effect on the cardiovascular system of a combination of pancuronium (0.048 mg/kg) and d-tubocurarine (0.288 mg/kg) was studied in five conditioned dogs anesthetized with fentanyl. Changes in heart rate, mean arterial pressure, central venous pressure, mean pulmonary artery pressure, pulmonary capillary wedge pressure, stroke volume, cardiac output, systemic vascular resistance and pulmonary vascular resistance were recorded 2, 5, 10, 20, 30, 40 and 50 minutes after administration of the drug combination. Arterial blood samples were assayed for estimation of histamine levels. There was a significant fall in central venous pressure and mean arterial pressure at 2 minutes (p less than 0.05) and a significant rise in heart rate at 2 and 5 minutes (p less than 0.05). These changes were not significant at 10 minutes. There was no significant change in the other parameters measured and no significant release of histamine. It is concluded that the smaller doses of pancuronium and d-tubocurarine used in combination in dogs do not completely attenuate the cardiovascular effects of either drug when used independently, but that the changes are transient and no longer significant at 10 minutes.