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.