TABLE VI.B. 2.

Association of OSA with worse postoperative outcomes

Study	Year	LOE	Objective	Study design	Study groups	Clinical endpoints	Conclusions
Khiani500	2009	3b	If the diagnosis of OSA using Berlin questionnaire will result in postoperative oxygen desaturation that needs supplemental oxygen following sedation for gastrointestinal procedures.	Cross sectional study	Berlin Questionnaire in patients undergoing sedation for GI procedures.	Rates of transient hypoxia, defined as a pulse oximetry measurement less than 92% requiring an increase in supplemental oxygen.	No significant difference in rate of transient hypoxia between the high- and low-risk groups (odds ratio 1.48; 95% CI, 0.58–3.80). Suggests that the majority of patients with no OSA can undergo conscious sedation for routine endoscopic procedures with standard monitoring practices.
Vasu et al.477	2010	2b	To determine whether high risk -OSA (HR-OSA) ≥ 3 on preoperative STOP-BANG (SB) questionnaire correlated with a higher rate of postoperative complications.	Retrospective Cohort study	Adults undergoing elective surgery at a tertiary care center who were administered the SB questionnaire. 135 patients were identified, 56 (41.5%) had high risk scores for OSA.	Pulmonary complications: Hypoxemia, atelectasis, pulmonary embolism, or pneumonia. Cardiac complications: New-onset atrial fibrillation, systemic hypotension, or myocardial infarction.	Patients at high risk of OSA had a higher rate of postoperative complications compared with patients at low risk (19.6% vs. 1.3%; p < 0.001). The SB questionnaire is useful for preoperative identification of patients at higher risk for complications.
Coté et al.471	2010	2b	To de termine: The preoperative prevalence of OSA using SB questionnaire related to the need for airway maneuvers and sedation related complications.	Prospective Cohort study	231 consecutive patients undergoing advanced gastrointestinal procedures under sedation were identified by SB and were classified as high risk for OSA (score, ≥ 3 of 8; SB+) or low risk (SB<3).	-Airway Maneuvers (AM): - defined as a chin lift, modified mask ventilation, nasal airway, bag-mask ventilation, and endotracheal intubation. -Sedation-related complications (SRCs) were defined as any duration of pulse oximetry less than 90%, systolic blood pressure less than 90 mm Hg, apnea, or early procedure termination.	The prevalence of SB+ was 43.3%. The frequency of hypoxemia was significantly higher among patients with SB+ than SB− (12.0% vs. 5.2%; relative risk [RR], 1.83; 95% confidence interval [CI], 1.32–2.54). The rate of AMs was also significantly higher among SB+ (20.0%) compared with SB− (6.1%) patients (RR, 1.8; 95% CI, 1.3–2.4).
Pereira et al.475	2013	2b	SB score can predict the risk of a patient having OSA and to evaluate the incidence high risk OSA (HR-OSA) in surgical patients admitted to the Post-Anesthesia Care Unit (PACU).	Prospective Cohort study	340 adult patients after noncardiac and non-neurological surgery were admitted to PACU. 179 (52%) were considered HR-OSA. HR-OSA if SB score≥3 and Low-risk of OSA (LR-OSA) if SB score<3 (LR-OSA).	Postoperative respiratory complications; residual neuromuscular blockade (NMB); hospital length of stay.	HR-OSA had: 1. More frequent hypoxia in PACU (9% vs. 3%, p = 0.012). 2. Higher incidence of residual neuromuscular blockade (NMB) (20% vs. 16%, p = 0.035). 3. Longer hospital stays.
Chia et al.495	2013	2b	To evaluate if the HR-OSA by SB can predict difficult intubation	Prospective cohort study	200 patients undergoing surgery under general anesthesia. 83 with HR- OSA based on the SB score ≥ 3. Mallampati score and tonsil size, as well as demographic data, were recorded preoperatively for all patients.	Difficulty of intubation defined by Cormack & Lehane grade III or IV or the need of an intubation aid, or the need of three or more intubation attempts. 7% had difficulty of intubation.	Rate of difficult intubation was higher in HR- OSA patients than in LR-OSA patients. (13.3% vs. 2.6%. (p < 0.001). A SB ≥ 3 was seen more frequently in the difficult intubation patients (78.6% vs. 38.7%) (p = 0.009).
Acar494	2014	2b	To evaluate if the HR-OSA by SB can predict difficult intubation	Prospective cohort study	200 patients undergoing surgery under general anesthesia. 83 with HR- OSA based on the SB score ≥ 3. Mallampati score and tonsil size, as well as demographic data, were recorded preoperatively for all patients.	Difficulty of intubation defined by Cormack & Lehane grade III or IV or the need of an intubation aid, or the need of three or more intubation attempts. 7% had difficulty of intubation.	Rate of difficult intubation was higher in HR- OSA patients than in LR-OSA patients. (13.3% vs. 2.6%. (p < 0.001). A SB ≥ 3 was seen more frequently in the difficult intubation patients (78.6% vs. 38.7%) (p = 0.009).
Mehta et al.501	2014	2b	To identify the prevalence of OSA by using the SB questionnaire and subsequent risk factors for airway interventions (AI) and sedation related adverse events (SRAE)	Prospective cohort study	243 patients undergoing routine gastrointestinal procedures under sedation. HR-OSA = SB ≥ 3 score, low risk −OSA = SB score < 3	Airway interventions (AI): Chin lift, mask ventilation, placement of nasopharyngeal airway, bag mask ventilation, unplanned endotracheal intubation, hypoxia, hypotension, or early procedure termination.	48% with HR- OSA. An SB score ≥3 was found not to be associated with occurrence of AI (relative risk [RR] 1.07), or SRAE (RR 0.81, 95% CI, 0.53–1.2) after adjustment for propofol dose, BMI, smoking, and age. HR-OSA patients are not at higher risk for airway intervention or sedation-related adverse events SRAE.
Proczko et al.485	2014	2b	To determine if morbidly obese patients using CPAP have fewer and less severe perioperative complications and a shorter hospital stay than patients with at least three SB criteria and are not using CPAP therapy.	Retrospective Cohort Study	3 groups of morbidly obese patients undergoing bariatric surgery. Group A: 99 patients who were diagnosed with PSG and used CPAP therapy before and after surgery. Group B: 182 patients who met at least three SB criteria and did not use CPAP. Group C: 412 patients who scored 1–2 items on the SB.	Postoperative hospital stays and pulmonary complications.	Group B patients had a significantly higher rate of pulmonary complications, worse oxygen saturation, respiratory rates, and increased length of stay in hospital. There were also two cases of sudden death in this group.
Seet et al.476	2015	2b	Predict independent risk factors for intraoperative and early postoperative adverse events.	Retrospective cohort study	5432 patients who underwent elective surgery were analyzed.	Adverse events: hypoxia, failed intubation or multiple attempts, dental injury, laryngospasm, bronchospasm, arrhythmia, hypertension and hypotension, unanticipated surgical bleeding, hypothermia, nerve injury, drug adverse reaction, equipment failure, unplanned ICU admission, post-anaesthesia care unit (PACU) time >2 h.	7.4% had unexpected intraoperative and early postoperative adverse events. These events were greater in patients with SB scores ≥ 3 Patients with SB scores ≥ 5 had a fivefold increased risk of unexpected adverse events.
Chung	2016	2a	Does the diagnosis of OSA changes the postoperative outcome?	Systematic Review	Patients undergoing surgery either under general or neuraxial anesthesia or sedation	Pulmonary, desaturation, difficult intubation, atrial fibrillation, cardiac complications, resource utilization, mortality.	The presence of OSA negatively influences perioperative outcomes.
Gokay et al.473	2016	4	SB vs. Berlin OSA questionnaires for evaluating potential respiratory complications.	Prospective Cohort Study	126 patients who underwent laparoscopic cholecystectomy.	Perioperative respiratory complications.	Both questionnaires found statistically significant differences between the low- and high-risk groups.
Chudeau et al.469	2016	2b	To evaluate whether the SB is predictive of perioperative respiratory complications in urgent surgery	Prospective cohort study	The SB questionnaire was used. 104 patients were HR-OSA and 85 LR-OSA.	Perioperative complications: respiratory complications, cardiac complications, neurologic complications, hospital length of stay and mortality.	HR-OSA vs. LR-OSA had: Higher respiratory complications (21% vs. 6%, a prolonged length of hospital stay (6 [3–12] vs. 4 [2–7] days. SB score was independently associated with respiratory complications (OR 1.44 [1.03–2.03].
Setaro et al.502	2018	4	To determine if longer monitoring of patients with OSA in the PACU improves patient outcomes after general anesthesia	Retrospec- tive cohort study	602 patients were evaluated. 68 patients (11%) had a confirmed and a presumptive diagnosis of OSA on chart review and screening STOP > 1.	Oxygen desaturation <95%, PACU length of stay	Most patients (96.5%) did not experience oxygen desaturation regardless of OSA diagnosis or a positive STOP score. Patients with OSA did not experience a higher incidence of respiratory symptoms while in the PACU.
Diagnosis of OSA and postoperative morbidity
Memtsoudis et al.474	2011	2b	To analyze perioperative demographics and pulmonary outcomes of patients with OSA after orthopedic and general surgical procedures	Case–control study	2,610,441 entries for orthopedic and 3,441,262 for general surgical procedures performed between 1998 and 2007. Of those, 2.52% and 1.40%, respectively, carried a diagnosis of OSA.	Aspiration pneumonia, adult respiratory distress syndrome (ARDS), pulmonary embolism (PE), and the need for intubation and mechanical ventilation.	OSA was associated with a significantly higher adjusted OR of developing pulmonary complications with the exception of PE.
Kaw et al.467	2012	1b	OSA is often undiagnosed before elective surgery and may predispose patients to perioperative complications.	Systematic review	13 studies (n = 3942). Studies without controls, involving upper airway surgery, and with OSA diagnosed by ICD-9 codes alone were excluded.	The incidence of postoperative desaturation, acute respiratory failure (ARF), postoperative cardiac events, and ICU transfers.	OSA was associated with significantly higher risk of postoperative cardiac events odds ratio (OR) 2.07; ARF OR 2.43; desaturation OR 2.27, and ICU transfer OR 2.81.
Opperer et al.468	2016	2a	The diagnosis of OSA has an impact on postoperative outcomes.	Systematic review	413,304 OSA and 8,556,279 control patients.	Combined complications of Cardiac, pulmonary, airway, mortality complications and resource utilization. Length of hospital stay and ICU admissions.	OSA patients had worse outcomes for pulmonary and combined complications, in-hospital mortality varied among studies.
Chan et al.465	2019	2b	To determine the association between OSA and 30-day risk of cardiovascular complications after major noncardiac surgery.	Prospective cohort study	1364 patients recruited without prior diagnosis of OSA and undergoing major noncardiac surgery. Monitored with nocturnal pulse oximetry and measurement of cardiac troponin concentrations.	Primary outcome was a composite of myocardial injury, cardiac death, heart failure, thromboembolism, atrial fibrillation, and stroke within 30 days of surgery.	Rates for composite complications: 30.1% for severe OSA, 22.1% for moderate OSA, 19.0% for mild OSA, and 14.2% for no OSA. OSA and risk for complications was significant only among patients with severe OSA (adjusted HR, 2.23 [95% CI, 1.49–3.34]; and not among those with moderate or mild OSA.
Diagnosis of OSA and postoperative mortality
Lockhart et al,481	2013	2b	To determine whether a prior diagnosis of OSA, or a positive screen for OSA is associated with increased risk for 30 days and one year mortality.	Prospective cohort study	14,962 patients, of whom 1939 (12.9%) reported a history of OSA. All patients completed preoperative OSA screening combination of the Berlin and Flemons STOP, and SB scores.	30 day postoperative mortality and 1-year mortality.	Screening tools identified a high prevalence of undiagnosed patients at risk for OSA (9.5%–41.6%). Neither a prior diagnosis of OSA nor a positive screen for OSA risk was associated with increased 30-day or one-year postoperative mortality.
D’Apuzzo et al.480	2012	2b	To determine if patients with OSA havea higher likelihood of postoperative in-hospital complications or increased costs after revision arthroplasty.	Retrospective cohort study	Nationwide sample of 258, 455 patients who underwent revision total hip or knee arthroplasty. Of these patients, 16,608 (6.4%) had been diagnosed with OSA.	In-hospital mortality, pulmonary embolism, and wound complications	OSA was associated with increased in-hospital mortality (odds ratio, 1.9; Pulmonary embolism (odds ratio, 2.1) Wound hematomas or seromas (odds ratio, 1.36) Increased postoperative charges ($61,044 vs. $58,813).
Mokhlesi et al,484	2013	2b	To determine if sleep disordered Breathing (SDB) is associated with higher hospital mortality, longer hospital stay, higher cost, respiratory and cardiac complications in bariatric surgeries	Retrospective Cohort study	Nationwide Inpatient Sample database of 91,028 adult patients undergoing bariatric surgeries	In-hospital death, total charges and length of stay, respiratory and cardiac complications	SDB was independently associated with decreased mortality (OR = 0.34), total charges (−$869), and length of stay. SDB associated with significantly increased emergent endotracheal intubation, noninvasive ventilation, and atrial fibrillation.
Lyons PG,503	2016	2b	To investigate the association between OSA and in-hospital mortality rapid response team (RRT) activation, ICU admission, intubation, and cardiac arrest on the wards in a large cohort of surgical and nonsurgical ward patients.	∖Retrospective cohort	93,676 ward admissions from 53,150 adult patients’ records were screened for the end points. OSA was identified in 5625 (10.6%) patients.	Primary outcome is in-hospital mortality. Secondary outcomes included length of stay (LOS), RRT activation, transfer to the ICU, endotracheal intubation, cardiac arrest on the wards, and a composite outcome of RRT activation, ICU transfer, and death.	OSA patients had more frequent RRT activations (1.5% vs. 1.1%) and ICU admission (8% vs. 7%) than controls but a lower inpatient mortality rate (1.1% vs. 1.4%). OSA was not associated with clinical deterioration and was associated with decreased in-hospital mortality.

Abbreviations: HR-OSA, high risk-OSA; ICU, intensive care unit; LR-OSA, low risk-OSA; SB, STOP-BANG.