Comparison of remifentanil consumption in pupillometry-guided versus conventional administration in children: a randomized controlled trial

BACKGROUND: Remifentanil is a commonly used opioid analgesic during anesthesia in children. Objective measurement of pain is required for adequate dosing of remifentanil. We investigated whether pupillometry-guided remifentanil administration can reduce intraoperative consumption of remifentanil in children. METHODS: We performed a single-blinded, prospective, randomized controlled trial from December 2018 through June 2019. Children who were 3-12 years of age and classified as having an American Society of Anesthesiologists physical status I-II and undergoing elective surgery under general anesthesia were included. Fifty-six fulfilled the inclusion criteria, and fifty-four completed the study. Participants were randomly assigned to either a pupillometry or conventional group. Patients in both groups received target-controlled infusion of remifentanil. In the pupillometry group, the adjustment of the remifentanil effect site concentration was determined by the pupillary diameter, whereas in the conventional group, the adjustment was based on the anesthesiologist's experience. Primary outcome was intraoperative remifentanil consumption, divided by patient weight and infusion time (ng kg(-1) min(-1)). RESULTS : Remifentanil consumption was reduced by 25% in the pupillometry group compared to the conventional group (116.7 +/- 56.0 ng kg(-1) min(-1) vs. 155.8 +/- 64.9 ng kg(-1) min(-1), respectively; P=0.02). There were no differences in intra-and postoperative blood pressure and heart rate. The incidences of postoperative desaturation or nausea/vomiting were not significantly different. CONCLUSIONS: Pupillometry-guided remifentanil administration in children undergoing general anesthesia can reduce the intraoperative remifentanil consumption.