Haemodynamic effects of intubating doses of pancuronium and rocuronium in cardiac surgical patients

Background: After the introduction of fast track cardiac anesthesia, the use of large dose narcotics for haemodynamic stability has reduced and anesthesiologist now rely on anesthesia drugs which are free of haemodynamic variability and are of shorter duration. Choice of muscle relaxant also became an important factor. Present study was conducted to assess and compare the haemodynamic effects of intubating doses of neuromuscular blocking drugs- pancuronium and rocuronium in patients undergoing cardiac surgery. Patients & Methods: In this prospective, randomized, double blind study, fifty patients were randomly assigned into two equal groups. Two minutes after induction of anaesthesia by midazolam and fentanyl, base line haemodynamic measurements were obtained. Patients in group I (n=25) received pancuronium 0.1mg kg^-1 and group II (n=25) rocuronium 0.6mg kg^-1. Heart rate, mean arterial blood pressure, systolic blood pressure, diastolic blood pressure, central venous pressure, pulmonary capillary wedge pressure, cardiac output, cardiac index and systemic vascular resistance were monitored at 2, 5 and 10 minutes interval after muscle relaxant. Result: Statistically significant (p<0.05) degree of rise in heart rate at all study points and increase in cardiac output and cardiac index at 10 minutes interval was observed in pancuronium group, while these parameters did not change significantly in rocuronium group. No significant alterations were observed in the other measured parameters in either of the two groups. Conclusion: The study demonstrated that when compared with pancuronium, rocuronium at intubating doses was associated with better haemodynamic stability in ischaemic heart disease patients.