Dexmedetomidine as Adjuvant for Suprazygomatic Maxillary Nerve Block in Children's Adenotonsillectomy

Inclusion Criteria: * Scheduled for elective partial adenotonsillectomy, * STUBR score ≥ 3, indicating significant sleep-disordered breathing * Patients whose parents are fluent in French of English will be enrolled Exclusion Criteria: * Scheduled to undergo total extracapsular adenotonsillectomy or adenoidectomy-only procedures * Patient requires prolonged intubation postoperatively * the anesthesiologist does not adhere to the standardized anesthesia protocol * Patients with neurological or cardiac congenital deficits, with cardiac arrhythmias (non-sinus rhythm), implanted pacemakers, on chronic therapy with drugs that have known effects on sympathetic and parasympathetic activity (antimuscarinics, beta-2 adrenergic agonists, alpha-1 adrenergic antagonists or antiarrhythmic agents, tricyclic antidepressants) * ASA physical status III or higher * Parent/legal guardians refuses to participate * Patients scheduled for surgery without an appointment at the Montreal Children's Hospital (MCH) Preoperative Clinic will not be enrolled in the study.