Cardio-vascular effects of vecuronium & pancuronium in patients undergoing elective closed mitral valvotomy

Vecuronium, a monoquaternary analogue of pancuronium, the neuromuscular blocker, was compared with pancuronium in 50 patients undergoing elective closed mitral valvotomy. The patients were randomly divided into two groups of 25 each, and the muscle relaxants were administered in a dose of 0.1 mg/kg body weight. Both the agents produced identical intubating conditions at 3 min. Vecuronium showed a significantly shorter onset of action, as compared to pancuronium. The latter significantly increased the heart rate throughout the period of study whereas vecuronium significantly decreased the heart rate, 25 min after administration. There was significant increase in the mean arterial pressure (MAP) at tracheal intubation in both the groups, which persisted throughout the period of study in pancuronium group. There was a significant fall in MAP at 30 min after relaxant in vecuronium group. The incidence of arrythmias was similar and significant in both the groups. Vecuronium, thus showed a quicker onset of action with minimal haemodynamic effects, as compared to pancuronium in patients undergoing closed mitral valvotomy.