Remifentanil vs Fentanyl in Children 7-12 After Urologic Surgery: Emergence Delirium and Recovery Quality

Background and Rationale

Emergence delirium, also termed emergence agitation, is a postoperative complication of pediatric anesthesia characterized by disturbances of perception and psychomotor behavior. It presents as a dissociative state of consciousness in which the child is restless, crying, non-cooperative, incoherent, inconsolable, or thrashing in bed. Reported incidence ranges from 25% to 80%, is higher in children under six years of age, and is observed most frequently after anesthesia with the volatile agents sevoflurane and desflurane.

Emergence delirium is not a self-limited nuisance. Affected children are at increased risk of inadvertent removal of intravenous cannulae, self-injury, and postoperative nausea and vomiting. The condition adversely affects recovery and well-being, prolongs hospital length of stay, increases health care costs, and may be followed by maladaptive behavioral change persisting for weeks after anesthesia.

Short-acting opioids, including fentanyl and remifentanil, are used in children both as sedatives and analgesics and to blunt the hemodynamic response to surgical stimulation and airway instrumentation; they have also been evaluated as preventive agents for emergence agitation. Remifentanil is attractive because of its rapid onset, absence of accumulation, and short context-sensitive half-time. However, published trials of remifentanil and emergence agitation under sevoflurane anesthesia are inconsistent: infusion-based regimens have been reported both to reduce and to increase the incidence of agitation. This trial is designed to resolve that inconsistency in a defined pediatric surgical population by directly comparing fentanyl with remifentanil maintenance, and to examine the relationship between intraoperative remifentanil use and the quality of postoperative recovery.

Objectives and Hypotheses

The primary objective is to compare the effect of intraoperative remifentanil versus fentanyl maintenance on the occurrence of postoperative emergence delirium. The primary hypothesis is that remifentanil produces less delirium than fentanyl in pediatric urologic surgery. The secondary objective is to examine the effect of remifentanil on the postoperative recovery process, with the hypothesis that its effect is dose-dependent and that higher infusion rates may deepen intraoperative hypotension.

Study Design and Conduct

This is a single-center, parallel-group, randomized controlled trial conducted with institutional review board approval, written informed consent from a parent or legal guardian, and assent from the child. Consent includes permission for data sharing with the research coordination center at the University of Health Sciences, Konya City Hospital. Participants are allocated in a 1:1 ratio to Group F (fentanyl) or Group R (remifentanil).

Anesthetic Protocol

All children receive intravenous midazolam 0.05 mg/kg five minutes before entering the operating room and are monitored with electrocardiography, pulse oximetry, non-invasive blood pressure measurement, and capnography. Anesthesia is induced with propofol 3-5 mg/kg. After loss of consciousness, Group F receives fentanyl 1 μg/kg as a bolus followed by 1 μg/kg intravenously every 30 minutes until the end of surgery, and Group R receives remifentanil 0.5 μg/kg followed by a continuous infusion of 1 μg/kg/min. In both groups a laryngeal mask airway is inserted 90 seconds after the bolus dose, and anesthesia is maintained with sevoflurane titrated to 1 MAC together with the assigned opioid. Immediately after induction, all patients receive preemptive intravenous paracetamol and ketamine 0.3 mg/kg.

At the end of surgery, sevoflurane and the assigned opioid are discontinued. The laryngeal mask airway is removed once the child shows a regular respiratory pattern and purposeful movement of the extremities without physical stimulation. Children are then observed in the post-anesthesia care unit, where emergence behavior, recovery milestones, and hemodynamic data are recorded, and are transferred to the ward after a further 30 minutes of observation once post-anesthesia discharge criteria are met.

Statistical Considerations

The sample size was projected from a previously published observational study of emergence and postoperative delirium. Assuming an emergence delirium prevalence of approximately 15.75%, 90% power, a two-sided alpha of 0.05, and an allowance of 4.91% for protocol deviations and adverse events, 88 participants per group (176 in total) were required.

Normality of distribution is assessed with the Shapiro-Wilk test. Demographic data and scale scores are summarized descriptively as mean ± standard deviation or as counts and percentages. Between-group comparisons of continuous variables are made with the independent-samples t test, and relationships between variables are examined by correlation analysis with reporting of confidence intervals. A two-sided P value < 0.05 is considered statistically significant.