Impact of Intranasal Dexmedetomidine-esketamine Administration on Postoperative Pain in Pediatric Patients Undergoing Adenotonsillectomy: a Randomized, Placebo-controlled Trial

Adenoid and tonsil surgery is a common surgical intervention for obstructive sleep-disordered breathing and is one of the most frequently performed surgeries in pediatric patients. The operation lasts approximately 45 minutes but is associated with significant postoperative pain; about 75% of children experiencing severe postoperative pain, which can affect swallowing and may cause psychological distress in children. About 12-16% of children return to hospital after discharge due to pain or dehydration. Postoperative analgesia during the initial two days is often inadequate. Currently, clinicians have explored various strategies to effectively manage postoperative pain after adenoid and tonsil surgery in children, but the results are unreliable and have multiple side effects.

Dexmedetomidine is a highly selective α2 receptor agonist with anxiolytic, sedative, and analgesic effects, and has a minimal impact on respiration at low doses. When used as an adjuvant analgesic after surgery, it improves analgesia, reduces opioid consumption, and decreases opioid-related adverse events. Dexmdetomidine is also used in pediatric patients but may produce bradycardia and hypotension at routine doses. Ketamine is a non-competitive N-Methyl-D-aspartic acid (NMDA) receptor antagonist and has been used as an anesthetic and analgesic for decades. Esketamine is the S-enantiomer of ketamine and has an analgesic potent of approximately 2 times of that of ketamine. Esketamine is also used in children but may produce neuropsychiatric side effects.

Dexmedetomidine and esketamine can each be administered intranasally. When used in combination, the sympathomimetic activity of esketamine may counteract the bradycardic and hypotensive effects of dexmedetomidine, and the sedative effect of dexmedetomidine can mitigate the neuropstchiatric side effects of esketamine. Intranasal administration of dexmedetomidine-esketamine combination has been used for preoperative sedation in children and may improve postoperative analgesia after adenoid and tonsil surgery. However, the success rate and efficacy of intranasal dexmedetomidine-esketamine are difficult to guarantee in preschool children due to poor cooperation and intranasal secretions.

This randomized trial is designed to test the hypothesis that intranasal administration of dexmedetomidine-esketamine combination after anesthesia intubation may improve postoperative analgesia in children undergoing adenoid and tonsil surgery.