PAIN MEDICINE Fentanyl-sparing Effect of Acetaminophen as a Mixture of Fentanyl in Intravenous Parent-/Nurse-controlled Analgesia after Pediatric Ureteroneocystostomy

ABSTRACT Background: Although acetaminophen has been used widely and is well tolerated in children, its efficacy and safety have not been clarified when combined with an opioid in intravenous parent-/nurse-controlled postoperative analgesia. Methods: Sixty-three children (aged 6 -24 months) who had undergone elective ureteroneocystostomies were enrolled in this prospective, randomized, double-blinded study. After the surgery, an analgesic pump was programmed to deliver fentanyl at a basal infusion rate of 0.25 g ⅐ kg Ϫ1 ⅐ h Ϫ1 and 0.25 g/kg bolus after a loading dose of 0.5 g/kg. In the fentanyl-acetaminophen group, acetaminophen was coadministered as a solution mixture at a basal infusion rate of 1.5 mg ⅐ kg Ϫ1 ⅐ h Ϫ1 and 1.5 mg/kg bolus after a loading dose of 15 mg/kg, whereas saline was administered to the fentanyl group. Results: Postoperative pain scores were similar between the two groups. The total dose (micrograms per kilogram per day, mean Ϯ SD) of fentanyl at postoperative days 1 (8.3 Ϯ 3.7 vs. 18.1 Ϯ 4.6, P ϭ 0.021) and 2 (7.0 Ϯ 2.4 vs. 16.6, P ϭ 0.042) was significantly less in the fentanyl-acetaminophen group compared with that in the fentanyl group. The incidences of vomiting (16.1 vs. 56.3%, P ϭ 0.011) and sedation (9.7 vs. 46.9%, P ϭ 0.019) were significantly lower in the fentanyl-acetaminophen group than those in the fentanyl group. Conclusions: Acetaminophen has significant fentanyl-sparing effects and reduces side effects when combined with fentanyl in intravenous parent-/nurse-controlled analgesia for postoperative pediatric pain management. P AIN after surgical procedures in children has received deserved attention, especially in children undergoing ureteral reimplantation who have suffered from moderate to severe pain due to postoperative bladder spasms. Although the precise mechanism of postoperative bladder spasms is not known, there is evidence that suggests that prostaglandins may play an important role. 1,2 A ready-to-use injectable acetaminophen (Perfalgan 10 mg/ml; Bristol-Myers-Squibb GmbH, Munich, Germany) works by inhibiting the cyclooxygenase enzyme in the central nervous system while sparing peripheral prostaglandin production. Intravenous acetaminophen has been shown to provide effective postoperative analgesia and is well tolerated in children, 3,4 but currently there has been no information regarding its continuous administration with opioids in pediatric pain management. The effective use of acetaminophen could contribute to keeping the postoperative opioid requirement and the potential for opioid-related adverse effects 5 to a minimum, particularly in infants and small children. We designed a prospective, randomized, double-blinded study to evaluate the effects of acetaminophen combined with fentanyl as an intravenous parent-/nurse-controlled analgesia (PNCA) 6 on postoperative analgesic efficacy and to What We Already Know about This Topic ❖ Acetaminophen is a useful adjunct for postoperative analgesia, but its application by parent-/nurse-controlled intravenous analgesia with fentanyl in infants has not been examined What This Article Tells Us That Is New ❖ In 63 infants (6 -24 months old), addition of acetaminophen to intravenous fentanyl parent-/nurse-controlled analgesia after ureteroneocystostomy reduced fentanyl dose, vomiting, and sedation by more than 50% 672 Anesthesiology, V 113 • No 3 • September 2010 Downloaded from anesthesiology.pubs.asahq.org by guest on 07/02/201