Effects of remifentanil on the sphincter of Oddi in a 3-year-old child: a case report.

Opioids cause spasm of the sphincter of Oddi. Remifentanil is metabolized enzymatically throughout the body. Its context-sensitive half-time is 3 to 4minutes. The effect of remifentanil on the sphincter of Oddi is unknown, especially in children. We recently encountered a patient in whom the administration of remifentanil caused spasm of the sphincter of Oddi, which resolved rapidly after discontinuation of remifentanil. A 3-year-old girl weighing 11.3kg was scheduled to undergo common bile duct excision with ductoplasty. Her diagnosis was congenital biliary dilatation. In the operating room, after achieving the initial induction through sevoflurane (5%) and intravenous rocuronium (10mg), she was intubated and administered a continuous paravertebral block by levobupivacaine (25mg/10mL +2.5mg/h). General anesthesia was maintained with sevoflurane (2%), remifentanil (0.5 μg kg(-1) min(-1)), and oxygen (fractional inspired oxygen tension, 0.33). The first intraoperative cholangiogram obtained via the cystic duct tube showed obstruction at the terminal end of the common bile duct. We injected scopolamine butylbromide (5mg, intravenous) to relax the sphincter of Oddi. However, the next cholangiogram obtained 3minutes later still showed an obstruction. We speculated that the obstruction may have been caused by remifentanil-induced spasm of the sphincter of Oddi. Therefore, we stopped administering remifentanil; 2minutes later, we achieved satisfactory passage of the contrast material to the duodenum. The predicted plasma concentrations of remifentanil at the time of stopping its administration and at the time of disobliteration were 6.38and 2.55ng/mL, respectively. The patient's postoperative course was uneventful. In patients who have spasms of the sphincter of Oddi during the administration of remifentanil, the resultant obstruction can be treated effectively by reducing the infusion rate of remifentanil.