SMALL-DOSE HYPOBARIC LIDOCAINE-FENTANYL SPINAL-ANESTHESIA FOR SHORT-DURATION OUTPATIENT LAPAROSCOPY .2. OPTIMAL FENTANYL DOSE

We performed a double-blind, controlled trial to determine the optimal dose of intrathecal fentanyl in small-dose hypobaric lidocaine spinal anesthesia for outpatient laparoscopy. Sixty-four gynecological patie nts were randomized into three groups, receiving 0, 10, or 25 mu g fen tanyl added to 20 mg lidocaine and sterile water (total 3 mt). Adminis tration was with 27-gauge Whitacre needles and patients sat upright un til the block was >T-8. One patient in the 0-mu g fentanyl group requi red general anesthesia 40 min after the start of surgery, leaving 21 p atients per group. Three patients in each of the 0-mu g and 10-mu g fe ntanyl groups had mild discomfort with trocar insertion, or return of some sensation and felt discomfort or sutures toward the end of surger y. Shoulder-tip pain was less frequent in the 25-mu g than 0-mu g fent anyl group, 28% vs 67% (P < 0.0166). Intraoperative supplementation wi th alfentanil (+/- propofol) was needed less often in the 25-mu g than 0-mu g fentanyl group, 43% vs 76% (P = 0.028). Recovery of sensation took longer in the 25-mu g than in the 0-mu g and 10-mu g fentanyl gro ups, 101 +/- 21 vs 84 +/- 20 and 87 +/- 18 min(P < 0.05), although mot or recovery and discharge times were the same. Postoperative analgesia was needed earlier in the 0-mu g than in the 25-mu g fentanyl group, median 54 (13-120) vs 87 (65-132) min (P < 0.05). Pruritus was the onl y side effect that occurred more often in the 10-mu g and 25-mu g grou ps than in the 0-mu g fentanyl group, 62% and 67% vs 14% (P < 0.0166). One patient required an epidural blood patch for postdural puncture h eadache. Based on these results, we concluded that 25 mu g intrathecal fentanyl is required when 20 mg lidocaine is used for hypobaric spina l anesthesia (SA) to ensure reliable, durable anesthesia, reduce shoul der-tip pain, and minimize the need for intraoperative supplementation . This dose provides longer postoperative analgesia and does not incre ase side effects apart from pruritus. SA with small-dose hypobaric lid ocaine-fentanyl was found to be a satisfactory technique for outpatien t laparoscopy, although postdural puncture headache can occur in some patients.