Intranasal Dexmedetomidine-esketamine Administration and Postoperative Pain in Pediatric Patients

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

Postoperative pain after adenoid and tonsil surgery is significant, with approximately 75% of pediatric patients experiencing severe postoperative pain. Currently, there is a lack of clinical strategies to safely and effectively manage postoperative pain in children undergoing adenoid and tonsil surgery. Dexmedetomidine and esketamine can achieve appropriate sedation levels and alleviate postoperative pain when used in children. Both drugs can be administered intranasally, and their pharmacological effects complement each other, reducing side effects. This study aims to investigate whether intranasal administration of dexmedetomidine-esketamine combination can improve postoperative analgesia in children undergoing adenoid and tonsil surgery.

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.

Inclusion Criteria:

• Aged 3-7 years old.
• Scheduled to undergo adenoidectomy and/or tonsillectomy under general anesthesia.
• Provides written informed consent by the guardian.

Exclusion Criteria:

• Unsuitable for intranasal administration due to nasal diseases (such as rhinitis, nasal polyps, or any condition causing nasal congestion).
• Clearly diagnosed cardiovascular and respiratory diseases.
• Communication barriers due to delayed neurological development or visual or hearing impairments.
• Traumatic brain injury or neurosurgery.
• Abnormal liver and kidney function (biomarkers higher than twice of the upper normal limits).
• Amercian Society of Anesthesiologists classification ≥ III.
• Body mass index higher than the 95th percentile of the age- and sex-standardized references.
• Allergic to dexmedetomidine and/or esketamine.
• Any other conditions that are deemed unsuitable for study participation.