Recovery from neuromuscular blockade after either bolus and prolonged infusions of cisatracurium or rocuronium using either isoflurane or propofol-based anesthetics

We examined the recovery characteristics of cisatracurium or rocuronium aft er bolus or prolonged infusion under either isoflurane or propofol anesthes ia. Sixty patients undergoing neurosurgical procedures of at least 5 h were randomized to receive either isoflurane with fentanyl (Groups land 2) or p ropofol and fentanyl (Groups 3 and 4) as their anesthetic. Groups 1 and 3 r eceived cisatracurium 0.2 mg/kg IV bolus, spontaneously recovered, after wh ich time an infusion was begun. Groups 2 and 4 received rocuronium 0.6 mg/k g IV, spontaneously recovered, and an infusion was begun Before the end of surgery, the infusion was stopped and recovery of first twitch (T-1), recov ery index, clinical duration, and train-of-four (TOF) recovery was recorded and compared among groups by using appropriate statistical methods. Clinic al duration was shorter for rocuronium compared with cisatracurium using ei ther anesthetic. Cisatracurium T-1 75% recovery after the infusion was shor ter with propofol compared with isoflurane. Cisatracurium TOF 75% recovery was similar after either bolus or infusion, but rocuronium TOF 75% recovery after the infusion was delayed. Infusion rates decreased for cisatracurium but remained relatively constant for rocuronium regardless of the anesthet ic used. Isoflurane enhances the effect of both muscle relaxants but prolon ged cisatracurium recovery more than rocuronium. Of the two muscle relaxant s studied, rocuronium's recovery was most affected by length of the infusio n. Cisatracurium may be a more desired muscle relaxant for prolonged proced ures because recovery was least affected by prolonged infusion.