EFFECT OF INTRATHECAL SUFENTANIL ON ISOFLURANE REQUIREMENTS DURING LOWER ABDOMINAL-SURGERY

Study Objective: To determine the effect of intrathecal sufentanil on volatile anesthetic requirements during lower abdominal surgery. Desig n: Randomized, double-blind study. Setting: Military tertiary care hos pital. Patients: 15 female patients, ASA status I and II, undergoing e lective lower abdominal surgery. Interventions: After induction of ane sthesia, each patient had a lumbar puncture performed with a 24-gauge Sprotte needle through a Tuohy needle positioned in the epidural space to receive either intrathecal sufentanil 10 mu g or intrathecal norma l saline (control). An epidural catheter was then placed for use in po stoperative analgesia. Anesthesia was maintained in all patients with isoflurane, air, and oxygen. Gas flows were constant and the isofluran e concentration was adjusted at 5-minute intervals to maintain systoli c blood pressure within 20% of preoperative baseline. Measurements and Main Results: The mean end-tidal isoflurane concentration during the first hour of surgery was significantly lower in the sufentanil group (0.74 +/- 0.02%) compared with the control group (1.05 +/- 0.03%) (p = 0.006), an overall reduction of 28% in the isoflurane requirement. Co nclusion: Prior administration of intrathecal sufentanil significantly decreases the isoflurane requirement in surgical patients, in additio n to its previously demonstrated rapid onset and receptor efficacy.