POSTOPERATIVE EPIDURAL INFUSION - A RANDOMIZED, DOUBLE-BLIND, DOSE-FINDING TRIAL OF CLONIDINE IN COMBINATION WITH BUPIVACAINE AND FENTANYL

The aim of this randomized, double-blind trial of postoperative thorac ic epidural analgesic infusions was to determine whether clonidine at 10 mu g/h (group C10, n = 22), 15 mu g/h (Group C15, n = 24), or 20 mu g/h (Group C20, n = 24) improved postoperative analgesia in patients undergoing abdominal gynecologic surgery, without side effects or hemo dynamic changes, when added to a 5-mL/h infusion of 0.125% bupivacaine and fentanyl 2 mu g/mL (Group C0, n = 22). The 24-h study infusion wa s supplemented, as required, by patient-controlled epidural fentanyl. Groups were similar for age, weight, duration, and type of surgery. Cl onidine produced a dose-dependent improvement in analgesia at rest. On ly 20 mu g/h significantly increased the percentage of patients who ex perienced no pain with coughing (relative risk 1.44, 95% confidence in terval 1.24-1.94), reduced pain scores with coughing (P < 0.05), and s ignificantly lowered supplementary fentanyl requirements (P < 0.05). G roups were similar for sedation, pruritus, nausea, time to ambulation, and satisfaction with analgesia. Clonidine produced a dose-dependent decrease in blood pressure and pulse rate and an increase in vasopress or requirement (P < 0.01). Epidural clonidine infused at 20 mu g/h imp roves analgesia during coughing when combined with epidural bupivacain e-fentanyl in patients undergoing lower abdominal surgery but is assoc iated with hemodynamic changes and increased vasopressor requirement.