A RANDOMIZED DOUBLE-BLIND COMPARISON OF EPIDURAL SUFENTANIL VERSUS INTRAVENOUS SUFENTANIL OR EPIDURAL FENTANYL ANALGESIA AFTER MAJOR ABDOMINAL-SURGERY

This randomized double-blind study compared epidural sufentanil (S(EPI)) with intravenous sufentanil (S(IV)) or epidural fentanyl (F(EPI)) analgesia in 45 patients after major abdominal operations. On first complaint of severe postoperative pain, S(IV) patients were given a 15-mug bolus and then a 5 mug/h infusion of sufentanil intravenously. S(EPI) patients were given the same bolus and infusion, but epidurally. F(EPI) patients had a 60-mug bolus and 20 mug/h infusion of fentanyl epidurally. All patients also received a bolus injection and then an infusion of coded saline via the alternate route. Analgesic requirements were tailored continuously to individual needs by patient-controlled supplementary boluses of 3.1 mug of sufentanil or 12.5 mug of fentanyl, or by 50% reduction in opiate infusion rate at predetermined intervals. Pain scores, circulatory variables, and respiratory rate did not differ between groups. Mean opiate dose requirements (+/- SD) to maintain analgesia for 24 h were 202 +/- 43 mug (S(IV)), 149 +/- 45 mug (S(EPI)), and 627 +/-226 mug (F(EPI)). The relative analgesic potencies (AP) calculated from the equianalgesic dose requirement ratios were 1.4 for AP-sufentanil(IV/EPI) and 4.2 for AP-epidural(F/S). S(IV) patients required more supplementary boluses than S(EPI) patients, were more sedated during the entire treatment, and had higher PaCO2 and higher serum sufentanil concentrations within the first 3 h of treatment. In addition, severe respiratory depression occurred in four S(IV) patients soon after the start of treatment, despite serum sufentanil concentrations of less than 0.3 ng/mL. Although the two epidural groups required a similar number of supplementary boluses and had similar blood-gas results and equivalent serum concentrations, sedation was slightly more intense with sufentanil than with fentanyl. The authors conclude that although S(IV) and S(EPI) are almost equipotent, IV administration of an equipotent initial dose is hazardous because of the risk of respiratory depression. The higher degree of sedation observed with S(IV) during the entire treatment may be a point in favor of epidural administration. The equianalgesic dose of epidural sufentanil was found to be approximately four times less than the epidural fentanyl dose in pain treatment after abdominal operations.