Summary of studies investigating post-adenotonsillectomy morbidity rates for paediatric patients.

Table 4: Summary of studies investigating post-adenotonsillectomy morbidity rates for paediatric patients.

Authors	Study design	Patients	Incidence (No. [%]) of morbidity	Time of morbidity	Definition of morbidity/respiratory adverse event (AE)
Theilhaber, et al. [8]	Retrospective	OSA patients admitted to ICU post-adenotonsillectomy	26/72 [36.1]	Median time = 165 minutes	• Mild AE : Saturation < 95% requiring supplementary O₂ or repositioning • Severe AE : desaturation treated by bag & mask ventilation, CPAP, BiPAP, oropharyngeal airway or re-intubation, and unplanned ICU admission
Kieran, et al. [13]	Retrospective	OSA and Non-OSA patients	294/4092 [7.2]	-	• Saturations < 90%
Statham, et al. [14]	Retrospective	OSA patients	149/2315 [6.4]	-	• SpO₂ < 90% requiring O₂ supplementation or diuretic therapy • Apnoea/increased work of breathing requiring nasopharygeal airway support/CPAP/intubation & mechanical ventilation • Chest radiographic evidence of atelectasis, infiltrates, edema, pneumomediastinum, pneumothorax, or pleural effusion
Kalra, et al. [15]	Retrospective	OSA patients	198/3739 [5.3]	-	• SpO₂ < 90% requiring O₂ supplementation for > 8 hrs or diuretics • Apnoea/increased work of breathing requiring nasopharygeal airway support/CPAP/intubation & mechanical ventilation • Chest radiographic evidence of atelectasis, infiltrates, edema & air fluid collection in pleural cavity
Brown, et al. [10]	Retrospective	OSA patients a) Urgent adenotonsillectomy^* b) Elective adenotonsillectomy	a) 33/54 [61] b) 16/44 [36]	a) Minor intervention group [22/33]: • 36.4% < 1 hr post-op Major intervention group [11/33]: • 72.7% < 1 hr post-op b) Not documented	• Saturation < 95% or • Airway obstruction or • Requiring intervention
Wilson, et al. [16]	Retrospective	OSA patients	34/163 [21]	-	• Saturation < 95% or • Airway obstruction or • Requiring medical interventions eg. O₂ administration, jaw thrust, artificial airway, positive pressure ventilation, reintubation
Biavati, et al. [17]	Retrospective	Patients with obstructed breathing during sleep	8/355 [2.25]	-	• Upper airway obstruction, oxygen desaturations less than 90% and interventions (eg placement of a nasopharyngeal airway, endotracheal intubation, or administration of supplementary oxygen) • A planned post-operative admission with interventions • An unplanned post-operative admission • Readmission after discharge for airway complications, or any airway complication that was managed on an outpatient basis
Gerber, et al. [18]	Prospective	OSA and non-OSA patients	44/29 [15.1]	-	At least 1 of the following occurring ≥ 2 hrs after surgery: • O₂ saturation level < 90% for ≥ 10 sec • An obstructive breathing pattern • Respiratory distress requiring intervention
Rosen, et al. [19]	Retrospective	OSA patients	10/37 [27]	'within hours of surgery'	• Saturations < 80% or • Snoring, increased respiratory effort, or • Requiring intervention eg. repositioning, supplemental oxygen, CPAP/BiPAP, prolonged intubation or reintubation
McColley, et al. [20]	Retrospective	OSA patients	16/69 [23]	'Up to 14 hours after completion of the operative procedure'	• Saturations ≤ 70% and/or • Hypercapnia (PaCO > 45 mmHg) • Requiring nurse/physician intervention
Wiatrak, et al. [21]	Retrospective	OSA and non-OSA patients	14/20 [70]	-	• O₂ desaturation > 90% requiring any combination of supplemental oxygen, placement of a nasopharyngeal airway, or endotracheal intubation • Postoperative obstruction apnoea, manifested by a cessation of airflow in the presence of respiratory muscle activity for > 10 s • Post-operative central apnoea, manifested by a cessation of airflow for periods > 10s with no observable respiratory muscle activity

^*: Urgent adenotonsillectomy is defined by Brown, et al. as adenotonsillectomy being performed during same hospital admission following diagnosis of OSA in a sleep study.