Cardiovascular effects of vecuronium, atracurium, pancuronium, metocurine and RGH-4201 in dogs

The effect on the cardiovascular haemodynamic status of five neuromuscular blocking drugs, RGH-4201, vecuronium, atracurium, pancuronium and metocurine, was studied in five conditioned foxhounds anaesthetised with fentanyl. Changes in heart rate, mean arterial blood pressure, central venous pressure, mean pulmonary artery pressure, pulmonary capillary wedge pressure, and cardiac output were recorded at 2, 5, 10, 20 and 30 min after administration of the drugs. From these, stroke volume, systemic vascular resistance and pulmonary vascular resistance were calculated. Administration of RGH-4201 was followed by a pronounced increase in heart rate, accompanied by an increase in cardiac output and a decrease in systemic and pulmonary vascular resistance. Metocurine and pancuronium resulted in a decrease of right and left filling pressures and systemic-/pulmonary vascular resistance. Changes after atracurium, vecuronium and metocurine were minimal. It is concluded that RGH-4201 causes major alterations in the cardiovascular haemodynamic status in dogs anaesthetised with fentanyl when compared to vecuronium, atracurium, metocurine and pancuronium. With respect to cardiovascular stability, atracurium and vecuronium offer advantages.