HAEMODYNAMIC EFFECTS OF TUBOCURARINE, GALLAMINE AND SUXAMETHONIUM IN DOGS

SUMMARY In anaesthetized open-chest dogs, neuromuscular blocking doses of tubocurarine reduced phasic aortic flow, aortic blood pressure, stroke volume, heart rate, cardiac output and peripheral resistance. These haemodynamic effects could be attributed to blockade of sympathetic ganglia and to histamine release. Paralyzing doses of gallamine slightly increased phasic aortic flow, stroke volume and cardiac output; such changes could be related to cardiovagal block. Blood pressure and peripheral resistance were slightly reduced. Contrary to known effects in anaesthetized patients, gallamine or atropine did not produce important tachycardia in anaesthetized dogs. Suxamethonium caused a small reduction in peripheral resistance; phasic aortic flow, stroke volume and cardiac output were slightly increased. These minor circulatory disturbances may be attributable to muscarinic effects of the drug.