ObjectivesClassify post-adenotonsillectomy (AT) respiratory support, identify variables that predict these interventions, and evaluate outcomes in children with extreme obstructive sleep apnea (OSA). MethodsRetrospective chart analysis was performed on patients found to have apnea/hypopnea index (AHI) > 100 events/h. Patients with chronic diseases other than obesity were excluded. ResultsForty-one subjects were studied, average age of 11.4 ± 4.3 years, majority (73.1%) were Hispanic, with a mean total AHI (TAHI) of 128.1 ± 22.9/h. Twenty-eight (68.3%) patients underwent AT. Lower age (P < 0.001), lower BMI Z-score (P < 0.01), higher OAHI (P < 0.05) were associated with having surgery. Eleven out of 28 (39.3%) surgical patients required respiratory support (oxygen or positive airway pressure) postoperatively. Longer % total sleep time SpO2 <90% during PSG (P < 0.05) and lower SpO2 nadir (P < 0.05) were associated with requiring airway support. No patients experienced mortality, reintubation, or hospital readmission following AT, with majority (71.4%) discharged 1 day post-operatively. Eleven (57.9%) of the 19 patients who had a postoperative PSG had residual OSA, defined as AHI >5 events/h, but there was a significant improvement in TAHI (P < 0.01). ConclusionOur findings confirm the need for postoperative observation in a controlled setting for patients with extreme OSA undergoing AT. Although at higher risk of needing respiratory support, those patients undergoing AT for extreme OSA did not require re-intubation post-operatively or suffer serious harm. Barring contraindications to AT, surgery may still be a first-line therapy for some children with extreme OSA.