[Cardiovascular effects after bolus administration of cisatracurium. A comparison with vecuronium]

Cisatracurium-one of the ten stereoisomers of atracurium-is an intermediate long-acting non-depolarizing neuromuscular blocking agent. Cardiovascular reactions have been described after administration of cisatracurium or vecuronium in surgical patients.

After approval by our institutional review board, 62 patients (ASA I-II) were randomly assigned to three groups to either receive 3xED95 or 5xED95 of cisatracurium or 3xED90 of vecuronium prior to intubation as a bolus. After oral premedication with 2 mg lormetazepam anaesthesia was induced with thiopental (4-12 mg/kg) and maintained with O2/N2O and isoflurane (1.5%-2%). Six minutes after administration of thiopental, patients received the muscle relaxant. Six minutes later 0.1-0.2 mg fentanyl was given and the trachea was intubated. Heart rate (HR) and blood pressure (BP) were monitored every minute. Changes of heart rate or blood pressure > 20% compared to baseline were defined as clinically significant.

After application of the study drug, median values of blood pressure and heart rate were stable. For each muscle relaxant, there were several patients who had statistically significant cardiovascular changes. After 3xED95 cisatracurium, 3 of 21 patients exhibited haemodynamic changes > 20% (2 exhibited hypotension and 1 tachycardia), while in the high-dose cisatracurium group 2 of 21 patients demonstrated a tachycardia that was predetermined to be statistically but not clinically significant. In the vecuronium group, 2 of 20 patients sustained statistically significant hypotension and 1 patient had statistically significant tachycardia. The frequency of all individual cardiovascular changes after the application of the muscle relaxant was not dose-dependent.

After the administration of cisatracurium in two different doses (3xED95 and 5xED95) or vecuronium (3xED90) only minor cardiovascular changes were observed. Both drugs proved to be safe for use during induction of anaesthesia in patients ASA I-II. With regard to its cardiovascular effects, cisatracurium shares with vecuronium the requirements of an ideal muscle relaxant.