Pathophysiological Mechanisms of Oral Melatonin in Reducing Preoperative Anxiety in Pediatric Patients Undergoing Therapeutic Cardiac Catheterization: A Randomized Double-Blinded Placebo-Controlled Study

Abstract

Background and Objective: Pediatric patients often experience heightened anxiety related to surgical interventions, which can complicate anesthetic management and affect surgical outcomes. This study aims to explore the biochemical mechanisms through which oral melatonin modulates preoperative anxiety and facilitates the separation from parents in pediatric patients undergoing cardiac catheterization in an Iraqi population. Methods: Eighty children, aged 4–12 years, diagnosed with a single congenital heart defect and scheduled for elective cardiac catheterization, were randomized into two groups. The melatonin group received 0.5 mg/kg oral melatonin at midnight and 90 minutes before the procedure, while the placebo group received a visually identical placebo at the same intervals. We monitored hemodynamic vital signs every 30 minutes post-morning premedication and assessed biochemical markers indicative of stress response. Anxiety and sedation levels were evaluated 30 minutes after premedication, during parent separation, and five minutes before anesthesia induction. Results: There was no significant demographic difference between the groups (p > 0.05). Initial anxiety levels before the second dose of premedication were similar across groups. Significant reductions in anxiety scores post-premedication, during parent separation, and pre-anesthesia induction were noted in the melatonin group (p < 0.001, p = 0.003, p = 0.020, respectively). Corresponding biochemical markers showed significant modulation in stress responses in the melatonin group compared to the placebo. Sedation levels were also significantly higher in the melatonin group at all assessment points (p < 0.001). Conclusion: Oral premedication with melatonin significantly modulates biochemical markers of stress and reduces preoperative anxiety in pediatric patients undergoing therapeutic cardiac catheterization. These findings highlight the potential of melatonin as a safe adjunct in pediatric anesthetic practice, with implications for both clinical outcomes and pathophysiological research.