Purpose: This study w as designed to evaluate the recovery times of patients undergoing ambulatory surgery w ith the short-acting, fastemergence anesthetic muscle relaxants, mivacurium, and rocuronium.
Methods: After IRB approval, patients w ho received either mivacurium or rocuronium at five surgical centers w ere included in the analysis. The primary outcome w as total time spent in the postanesthesia care unit (PACU) and/or second stage recovery unit. The ability to bypass the PACU w as also evaluated.1 The Wilcoxon rank sum test and chi-square test w ere used for comparisons. The interrelationships betw een patient characteristics, neuromuscular blocking agents, bypass of the PACU, surgery duration, surgical procedure, and use of reversal agent and inhalation agent w ere explored w ith a linear regression model. Statistical significance w as defined as p < 0.05.
Results: A total of 344 patients received mivacurium and 190 patients received rocuronium. Recovery times and surgical times, stratified by type of neuromuscular blocking agent and by PACU requirements, are presented in the below table. Patients who received mivacurium had a shorter recovery time than patients w ho received rocuronium, p < 0.0001. In both groups, if a patient bypassed the
PACU, the total recovery time w as significantly shorter than if a patient needed care in the PACU, p < 0.0001. Surgical duration was statistically different betw een the mivacurium and rocuronium groups. Bypass rates for the PACU w ere 29.1% and 21.6% for the mivacurium and rocuronium groups, respectively, p = 0.06. The factors statistically related to total recovery time with a baseline duration of 144 minutes w ere mivacurium use (-18 minutes), bypass ability (-41 minutes), females (+19 minutes), ENT procedures (+21 minutes), and surgery duration > 1 hour (+24 minutes), p < 0.05.
International Anesthesia Research Society (IARS), Tampa, Florida, March 2004
By J. L. Apfelbaum, Cynthia A. Walawander