EPIDURAL VS INTRAVENOUS-INFUSION OF ALFENTANIL IN THE MANAGEMENT OF POSTOPERATIVE PAIN FOLLOWING LAPAROTOMIES

Background: This study was designed to compare the efficacy of epidura l vs. intravenous administration of alfentanil for treatment of postop erative pain. Methods: Twenty patients were randomly allocated to one of the two study groups to receive either an epidural bolus dose (0.75 mg) followed by an epidural infusion (0.36mg/h) (EPI group) or an intr avenous infusion (0.36mg/h) of alfentanil (IV group) for 24 h. These d ose regimens were chosen such that equivalent and subanalgesic plasma concentrations of alfentanil were obtained. PCA-morphine was available to both groups. Morphine consumption, pain scores measured on a Visua l Analogue Scale (VAS) and the number of demands were used as variable s to evaluate the efficacy of the postoperative analgesic therapy. In addition plasma concentrations of alfentanil were measured. Results: T he mean plasma concentrations of alfentanil were similar and <20ng/ml in both groups. Total morphine consumption (EPI: 40mg, TV: 43mg), pain scores (time when the VAS-score>3.0; EPI: median 215 min; IV: median 215 min) and number of valid demands (EPI: median 25; IV: median 34) d id not differ between the groups. Conclusion: Compared to intravenous infusion of alfentanil epidural infusion resulting in the same plasma concentrations is not more effective in relieving postoperative pain. In view of this observation we were not able to demonstrate a spinal m echanism of alfentanil.