POSTOPERATIVE ANALGESIA AND PLASMA-LEVELS AFTER TRANSDERMAL FENTANYL FOR ORTHOPEDIC-SURGERY - DOUBLE-BLIND COMPARISON WITH PLACEBO

Study Objective: To determine whether transdermal fentanyl can provide a significant component of postoperative analgesia. Design: Randomize d, double-blind study. Setting: Inpatient surgery in a university hosp ital. Patients: 40 adult patients scheduled for orthopedic surgery wit h general anesthesia. Interventions: 20 patients in each group had gen eral anesthesia with propofol, isoflurane in nitrous oxide and oxygen (O-2), and small boli of alfentanil or sufentanil. Preoperatively, the first group (F) received a transdermal therapeutic system fentanyl pa tch (75 mu g/hr) for 72 hours, and the second group (P) received a pla cebo patch. Morphine was given postoperatively according to clinical n ecessity. Measurements and Main Results: Morphine consumption, pain vi sual analog scale, and eventual sedation were assessed, as well as res piratory rate and blood pressure. Plasma fentanyl concentrations were determined. Only 11 Group F patients needed morphine compared with 19 Group P patients, and mean morphine dose was significantly lower in Gr oup F. One Group F patient had decreased O-2 saturation and intense se dation, necessitating administration of naloxone. The mean maximum pla sma fentanyl concentration in Group F was 1.63 ng/ml. Conclusion: Effi cacy of transdermal fentanyl for postoperative pain relief is shown, b ut intense respiratory depression is sometimes seen.