Requirements for muscle relaxants during radical retropubic prostatectomy

Background: The need for the routine use of muscle relaxants to provide an adequate surgical field for intraabdominal surgery has not been established. This study tested the hypothesis that vecuronium decreases the frequency of unacceptable operating conditions for patients undergoing radical retropubic prostatectomy who are anesthetized with isoflurane and fentanyl. Methods: After obtaining informed consent, patients in blinded, placebo-controlled study were randomized to receive either an infusion of vecuronium or saline (placebo) beginning 5 min after fascial incision during the maintenance of anesthesia with at least 1 minimum alveolar concentration end-tidal isoflurane and fentanyl infusion. The surgical field was graded from 1 (excellent) to 4 (unacceptable) by the surgeons at 15-min intervals. If a grade 4 rating occurred (defined as a treatment failure), the patient received rescue vecuronium. Results: A total of 120 patients are included in this report (59 in the vecuronium group and 61 in the placebo group). The frequency of treatment failure in the placebo group was 17 of 61 (27.9%) versus 1 of 59 (1.7%) in the control group who received vecuronium (P < 0.001). Thirty-eight patients (62.3%) in the placebo group and 52 patients (88.1%) in the vecuronium group had surgical field ratings of ≤ 2 (good to excellent) at each time assessed throughout the procedure. Conclusion: The study hypothesis was confirmed. However, an isoflurane-fentanyl anesthetic alone produced a good to excellent surgical field in approximately two thirds of patients undergoing radical retropubic prostatectomy without the use of muscle relaxants. Thus, the routine use of muscle relaxants in adequately anesthetized patients undergoing this procedure may not be indicated.