THE HEMODYNAMIC-EFFECTS OF ROCURONIUM AND VECURONIUM ARE DIFFERENT UNDER BALANCED ANESTHESIA

Background: Rocuronium has been reported to have minimal haemodynamic effects. However, this conclusion has been drawn primarily from invest igations conducted under narcotic-based anaesthesia. This study was de signed to evaluate the cardiovascular effects of rocsuronium under iso flurane/N2O/fentanyl anaesthesia and to compare rocuronium's haemodyna mic effects to those of vecuronium and pancuronium. Methods: Anaesthes ia was induced with fentanyl 2 mu g/kg, thiopentone 4 mg/kg, and suxam ethonium 0.5 mg/kg in 75 ASA I or II patients. After tracheal intubati on, anaesthesia was maintained with isoflurane 0.5% and N2O 50% in oxy gen. Five min after intubation (baseline), patients randomly received either vecuronium 100 mu g/kg, rocuronium 600 mu g/kg, rocuronium 900 mu g/kg, rocuronium 1200 mu g/kg, or pancuronium 140 mu g/kg. One min after administration of muscle relaxant, mean arterial pressure (MAP) and heart rate (HR) were recorded and were subsequently measured at 1- min intervals for the next 4 min. Results: HR decreased significantly (P<0.05) at all times compared to baseline in patients receiving vecur onium. HR significantly (P<0.05) increased in those receiving rocuroni um 1200 mu g/kg or pancuronium. Patients who received vecuronium had a significant (P<0.05) decrease in MAP at all times compared to baselin e. Comparing results between groups, patients who received rocuronium or pancuronium had significantly (P<0.05) higher MAP compared to those administered vecuronium. Conclusion: The haemodynamic effect of rocur onium and vecuronium are different under balanced anaesthesia. Rocuron ium may attenuate the fall in MAP that often occurs under balanced ana esthesia without surgical stimulation. (C) Acta Anaesthesiologica Scan dinavica 41 (1997).