Postoperative complications in patients with obstructive sleep apnea: a retrospective matched cohort study.
OBJECTIVE
Obstructive sleep apnea (OSA) is presumed to be a risk factor for postoperative morbidity and mortality, but the current evidence is incomplete. This retrospective matched cohort study tested the hypothesis that OSA is a risk factor for the development of postoperative complications.


METHODS
Hospital ethics approval was obtained for the conduct of this study. The patients who were selected for the study were >18 yr of age, diagnosed preoperatively with OSA, and scheduled to undergo elective surgery. A cohort of surgical patients without OSA was used as a comparator group based on a one-to-one match. Matching criteria included gender, age difference <5 yr, type of surgery, and a <5 yr difference between two surgery dates. Summary data are presented and conditional logistic regression was used to identify risk factors for postoperative complications.


RESULTS
The 240 pairs of study subjects aged 57 +/- 13 yr included 184 (77%) males and 56 (23%) females. The OSA patients had a higher mean body mass index relative to their non-OSA counterparts (35 +/- 9 vs 28 +/- 6 kg . m-2, respectively) and a higher frequency of co-morbidities, including hypertension (48% vs 36%, respectively) and obesity (61% vs 23%, respectively). Also, the incidence of postoperative complications in the OSA patients was significantly greater (44% OSA group vs 28% non-OSA group; P < 0.05). The most commonly observed between-group difference was oxygen desaturation < 90% (17% OSA group vs 8% non-OSA group). The OSA patients who did not use home continuous positive airway pressure (CPAP) devices prior to surgery but required the use of a CPAP device after surgery had the highest rate of complications. Conditional logistic regression was used to diagnose OSA and pre-existing stroke as significant risk factors for developing postoperative complications. The hazard ratio for OSA was 2.0 (1.25-3.19).


CONCLUSIONS
Patients with diagnosed OSA have an increased incidence of postoperative complications, the most frequent being oxygen desaturation.
Department of Anesthesia, Toronto Western Hospital, University Health Network, Room 405, 2McL, 399 Bathurst Street, Toronto, ON M5T 2S8, Canada.
Pu
P
Liao
Balaji
B
Yegneswaran
Santhira
S
Vairavanathan
Paul
P
Zilberman
Frances
F
Chung
D000328:Adult; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D045422:Continuous Positive Airway Pressure / Q000379:methods; D017558:Elective Surgical Procedures / Q000009:adverse effects; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000150:complications*
D010100:Oxygen