THE EFFECT OF LOW-DOSE BUPIVACAINE ON POSTOPERATIVE EPIDURAL FENTANYLANALGESIA AND THROMBELASTOGRAPHY

We performed a prospective, randomized, double-blind study to determin e the effect of bupivacaine on postoperative epidural fentanyl analges ia and thrombelastography in 120 patients who underwent extensive gast rointestinal or genitourinary surgery. The patients were randomized in to four groups, 30 patients per group: Group I = epidural fentanyl (EF ), 10 mu g/mL in saline; Group II = EF with 0.1% bupivacaine; Group II I = EF with 0.15% bupivacaine; and Group nT = EF with 0.2% bupivacaine . Pain relief was evaluated by a visual analog scale (VAS), both at re st and during coughing, and by a visual rating scale (VRS). The VAS, V RS, degree of sedation, and side effects (nausea, vomiting, and prurit us) were evaluated every 2 h from 8:00 AM to 6:00 PM, for 24 h after s urgery. Forced vital capacities (FVCs) were determined before surgery and at 24 h after surgery. Blood was withdrawn for thrombelastography (TEG) measurements preoperatively, in the recovery room (PARR), and 24 h postoperatively. The VAS, VRS, sedation scores, changes in postoper ative FVCs, and the incidence of side effects were not statistically d ifferent among the four groups. The 24-h total volumes of infusion in the four groups (146 +/- 40 mt, 140 +/- 38 mL, 142 +/- 40 mL, 124 +/- 21 mL, respectively) were not statistically different from each other. There were no significant differences in the TEG values [reaction tim e (R), coagulation time (K), angle (alpha), and maximum amplitude (mA) ] among the four groups at anytime nor was there any difference betwee n the baseline, PARR, and 24-h TEG values within any group. We conclud e that the addition of low-dose bupivacaine does not improve the analg esic effect of an EF infusion or the postoperative coagulation status in this group of patients.