Remifentanil

The protocol treats 10 micrograms of remifentanil as equivalent to 1 mg of intravenous morphine for opioid equivalence calculations. The main between-group difference is the method used to guide remifentanil titration. During maintenance, remifentanil effect-site concentration will be kept between 1 and 6 ng/mL. In the control group, remifentanil is titrated by 0.5 ng/mL to keep mean arterial pressure within 20% of baseline. Prior opioid sedation history is recorded and classified to control for cumulative opioid tolerance as a confounding variable. Remifentanil is an ultra-short-acting opioid hydrolysed by plasma and tissue esterases, producing non-cumulative analgesia with fast offset. Remifentanil is maintained by target-controlled infusion during anaesthesia in both trial arms. The propofol-remifentanil combination carries a clinically significant risk of respiratory depression in paediatric patients. The primary outcome measures total intraoperative opioid dose from induction to anaesthesia termination in morphine milligram equivalents per hour. Remifentanil is the most widely used analgesic agent paired with propofol in paediatric procedural sedation.