A comparison of the onset and clinical duration of high doses of cisatracurium and rocuronium

STUDY OBJECTIVE: To determine the onset and clinical duration of cisatracurium and rocuronium in equipotent doses in balanced opioid/isoflurane anesthesia. DESIGN: Randomized, controlled study. SETTING: University hospital. PATIENTS: 40 healthy patients scheduled for elective surgery. INTERVENTIONS: Patients underwent anesthesia induction with thiopental or propofol with a cisatracurium intubating dose of either 0.15 or 0.2 mg/kg or a rocuronium dose of either 0.9 or 1.2 mg/kg. These doses correspond to three and four times the ED95 dose. MEASUREMENTS AND MAIN RESULTS: The onset time and time to 25% recovery of baseline first twitch in a train-of-four were determined using an accelerometric sensor. Rocuronium had a faster onset time that cisatracurium at equipotent doses (3 x ED95: 134 vs. 220 sec respectively, and at 4 x ED95: 95 vs. 162 sec). Recovery tended to be faster, but not statistically different for cisatracurium compared to rocuronium. CONCLUSIONS: With equipotent intubating doses of rocuronium and cisatracurium, rocuronium produces a more rapid onset of muscle relaxation. The data suggest a tendency toward more rapid clinical recovery of cisatracurium compared to equipotent doses of rocuronium, although these differences were not statistically significant.