RESUMO
Narcotic mu-agonists have been shown to increase the common bile duct pressure. With a recently introduced non-invasive ultrasonographic technique, we have demonstrated that morphine caused constriction of the common bile duct. We have now investigated the effect of highly potent, widely used mu-agonists, fentanyl and sufentanil on the diameter of the common bile duct using this technique in a double-blind, randomized study in 17 patients undergoing cholecystectomy. After premedication with midazolam and glycopyrrolate, anesthesia was induced by midazolam, 50 micrograms.kg-1 and thiopental, 3.0-5.0 mg.kg-1. Tracheal intubation was facilitated by succinyl-choline, 1.0 mg.kg-1 and muscle relaxation maintained with vecuronium. Anesthesia was maintained with enflurane or isoflurane and nitrous oxide in oxygen. The diameter of the common bile duct was determined before and at 4 and 8 minutes after the administration of the study drugs. One way analysis of variance and paired t-test were used for statistical analysis. P < 0.05 was considered significant. No significant change in common bile duct diameter was observed after i.v. placebo, nor were there any significant changes after fentanyl or sufentanil administration. Since the baseline common bile duct diameters were not significantly different among the three groups, fentanyl or sufentanil in the doses used had no more effect than a placebo on common bile duct diameter. It is concluded that fentanyl and sufentanil caused no effect on the common bile duct, therefore, these mu-agonists seem to be safe in patients in whom spasm of the common bile ducts should be avoided.
