Low-Dose Versus High-Dose Postoperative Naloxone Infusion Combined With Patient-Controlled Analgesia for Adolescent Idiopathic Scoliosis Surgery: A Randomized Controlled Trial

Abstract

Study design: Randomized controlled trial.

Objectives: The aim of this prospective randomized clinical trial was to compare low (0.5 μg/kg/h) and high (2.5 μg/kg/h) dose naloxone infusion on the time to tolerate liquids and meals after surgery, patient-controlled analgesia (PCA) opioid requirements, nausea and pruritus ratings, and hospital length of stay.

Summary of background data: Adolescents undergoing posterior spinal fusion often receive PCA after surgery and may experience common opioid-associated side effects, including nausea and pruritus. Low-dose naloxone infusion has been shown to reduce the incidence of pruritus and nausea while preserving analgesia, although an ideal dose has not been determined. Less is known about the potential for naloxone to improve bowel function after surgery.

Methods: Eighty-four patients (age 10-21 years) were randomly allocated to receive low- or high-dose naloxone infusion postoperatively. Surgical anesthetic consisted of propofol and opioid infusion with intrathecal morphine (10-15 μg/kg) at the conclusion of surgery. A visual analog scale (VAS) was used to rate nausea and pruritus.

Results: The groups had similar time to oral liquid intake after surgery and transition from PCA to oral pain medication. The VAS scores for pruritus and nausea were also similar, as was the need to treat these side effects. Morphine equivalents were similar between groups on postoperative day (POD) 0 and 1. On POD 2, the high-dose infusion group had significantly greater PCA bolus use (1.41±0.9 vs. 1.04±0.6; p<.05), although pain scores did not differ significantly. Hospital length of stay was similar for the two groups.

Conclusion: High-dose naloxone infusion was associated with similar rates of opioid side effects as low-dose. Increased PCA use noted on POD 2 may represent partial reversal of opioid analgesia in the high-dose naloxone group.

Level of evidence: Level 1.

Keywords: Adolescent; Narcotic antagonists; Pain; Patient-controlled analgesia; Scoliosis; Spinal fusion.