Comparison of intubating conditions and hemodynamic effects of rocuronium and mixture of vecuronium and rocuronium in patients undergoing elective coronary artery bypass graft surgery

Haemodynamic stability is an integral and essential goal of any anaesthetic management plan in patients with cardiac disease. Patients who have limited coronary reserve are susceptible to any factor like pulmonary vascular resistance. This may either induce or worsen preexisting ischemia which may be associated with postoperative myocardial infarction. The present study was conducted on 40 patients American Society of Anesthesiologist (ASA) grade III and IV undergoing elective cardiac surgery in the department of anaesthesia, SMS Medical College and Hospital, Jaipur. Patients of either sex were included and same anaesthetic management was carried out in each patient. After induction of anaesthesia, patients were divided randomly into two groups according to the muscle relaxant used. Group I received Inj. rocuronium while Group II received Inj. rocuronium and vecuronium. Haemodynamic parameters comprising of heart rate, mean arterial pressure, central venous pressure, mean pulmonary artery pressure and pulmonary capillary wedge pressure were measured preoperatively, pre induction, post induction, post relaxant, post intubation (1 min) and after 3, 5 and 10 min after intubation. Rocuronium has maintained excellent cardiovascular stability for the dose used in present study. There was an increase in heart rate following rocuronium administration but the average maximum increase of 5 beats/min was clinically insignificant. Rocuronium is 3-6 times less potent than vecuronium as a neuromuscular blocker but is slightly more potent in blocking the responses to either vagal or preganglionic sympathetic stimulation. Therefore the margin between the neuromuscular blocking effect and the unwanted vagal blocking action is less than that of vecuronium. Thus the slight increase in heart rate may be beneficial along with opioids used for induction of these patients. The present study showed that both vecuronium and rocuronium were associated with clinically unimportant hemodynamic changes.