CONSIDERATION OF THE OPTIMAL EPIDURAL FENTANYL DOSES IN ABDOMINAL-SURGERY

Study Objective: To determine an optimal dose of epidural fentanyl in open abdominal surgery by examining the effects of different doses of epidural fentanyl in combination with or without low concentration of lidocaine on hemodynamic and endocrine responses to surgical stress. D esign: Prospective randomized study. Setting: University hospital. Pat ients: 40 ASA physical status I and II patients scheduled for elective abdominal surgery including gastrectomy (n = 20), colectomy (n = 10) liver tumor resection (n = 2), pancreatectomy (n = 3), pancreaticoduod enectomy (n = 1), low anterior resection (n = 3), and cholecystectomy (n = 1). Interventions: Patients were randomly allocated to one of two groups: epidural fentanyl with 0.5% lidocaine (Group L + F; n = 25) o r epidural fentanyl alone (Group F; n = 15). Both two groups were divi ded into subgroups; in Group L + F, epidural fentanyl was administered as doses of 0, 0.3 1, 3 and 5 mu g/kg in 5 patients each. In Group F, epidural fentanyl was administered as doses of 1, 3 and 5 mu g/kg in 5 patients each. Hemodynamic data and plasma catecholamine concentrati ons were compared between before the epidural injection and immediatel y after peritoneal incision. Measurements and Main Results: There was no difference in mean arterial pressure (MAP) and heart rate (HR) betw een Group L + F and Group Fat the time before epidural adminstration o f fentanyl, 20 minutes after epidural fentanyl, and immediately after peritonal incision. However, there were significant decreases in MAP i mmediately after shin incision in epidural fentanyl 0 and 3 mu g/kg in Group L + F patients and also in epidural fentanyl 1 and 3 mu g/kg in Group F patients. HR significantly decreased in epidural fentanyl 5 m u g/kg of Group L + F at peritoneal incision (p < 0.05). Plasma epinep hrine decreased significantly in fentanyl 3 and 5 mu g/kg in Group L F immediately after peritoneal incision (p < 0.05), whereas the incre ase in norepinephrine was significant in Group F (p < 0.01). Plasma do pamine significantly increased only in fentanyl 1 mu g/kg in Group F ( p < 0.05). Conclusion: Epidural fentanyl 3 mu g/kg with 0.50% lidocain e may be most adequate for laparotomy because these doses caused neith er bradycardia nor increments of norepinephrine perioperatively. (C) 1 998 by Elsevier Science Inc.