To reverse or not to reverse: an evaluation of reversal of mivacurium chloride in women undergoing outpatient gynecological procedures.

BACKGROUND

A double-blind, randomized study compared differences between patients administered edrophonium and those administered placebo after mivacurium infusion. Neuromuscular blockade was quantified using the ParaGraph 1800 nerve stimulator-monitor (Vital Signs, Totowa, NJ), which can deliver a train-of-four stimulus to the ulnar nerve and quantify the ratio of the fourth twitch to the first twitch.

METHODS

With Investigational Review Board approval and informed consent, 30 healthy outpatient gynecological surgery patients ASA I or II, aged 21 to 37 years, were randomly assigned to treatment or placebo. In a double-blind manner, one group received edrophonium (1 mg/kg) and atropine (0.01 mg/kg) reversal (E/A) and the other group received placebo (P) to recover spontaneously from a mivacurium infusion. Anesthesia was induced and a rapid infusion of mivacurium chloride (0.2 mg/kg) was administered. An infusion of mivacurium chloride was then initiated at a rate of 6-7 microg/kg/min to maintain neuromuscular blockade. Group differences in recovery time (time between administration of the edrophonium or placebo and a 5-second head lift followed by tracheal extubation) were compared, as was time from tracheal extubation to discharge from the postanesthesia care unit (PACU). Nausea and vomiting were documented until the patient was discharged from the hospital; a 24-hour follow-up evaluation was completed by telephone.

RESULTS

Each group contained 15 patients, and their demographics were similar. The mean recovery time for E/A was statistically shorter than for P (P, 9.7 +/- 4.8 minutes; E/A, 6.1 +/- 3.9 minutes; p = 0. 017). There were no statistically significant differences found in the incidence of nausea and vomiting (P, 4; E/A, 6) or in time to discharge from the PACU.

CONCLUSION

Recovery from a mivacurium chloride infusion is shorter by 3.6 minutes (margin of error +/- 3.3 minutes) when reversal with edrophonium/atropine is used. There is no difference in time to discharge from PACU and no evidence of differences in nausea and vomiting.