What’s New in the Patient Safety World

March 2012


Postoperative Complications with Obstructive Sleep Apnea



We’ve done multiple columns on the risks in the perioperative period of patients with known or suspected obstructive sleep apnea (OSA). A new study (Kaw 2012) identified patients who had undergone polysomnography and then had noncardiac surgery. From the group they identified 282 patients with apnea-hypopnea indices (AHI) of 5 or above as having OSA. They then developed a propensity score-matched control group from those who had a polysomnogram but had AHI indices less than 5. The group with OSA was almost 7 times more likely to have overall complications, 8 times more likely to have postoperative hypoxemia, and over 4 times more likely to require transfer to an ICU. They also had longer lengths of stay.


Respiratory failure accounted for 35% of the complications. A previous study (Memtsoudis 2011) had also shown about a 5-fold increase in respiratory failure in patients with OSA undergoing noncardiac surgery. The latter study showed patients with OSA developed pulmonary complications more frequently than their matched controls after both orthopedic and general surgical procedures.


Kaw et al. discuss that the negative effects of sedative, analgesic and anesthetic agents can worsen OSA both by decreasing pharyngeal tone and by decreasing the arousal responses to hypoxia, hypercarbia, and obstruction. They also note that some of the “later” events may be due to the rebound increase in REM sleep that is higher, for example, on the third night rather than first night.


A brief article (Nitsun 2012) on using the STOP-BANG questionnaire to screen for OSA pre-operatively also gave some common sense guidelines for managing patients with suspected OSA postoperatively. Those recommendations include considering opioid-sparing pain management, full reversal of any neuromuscular blockade used, monitoring the patient with capnography, and ensuring patients are not kept supine when extubated. It also has a discussion about whether procedures in patients with known or suspected OSA should be done in an ambulatory vs. hospital setting.



See some of our prior columns on obstructive sleep apnea in the perioperative period:


Patient Safety Tips of the Week:

June 10, 2008              Monitoring the Postoperative COPD Patient

August 18, 2009           Obstructive Sleep Apnea in the Perioperative Period

August 17, 2010           Preoperative Consultation – Time to Change

July 13, 2010               Postoperative Opioid-Induced Respiratory Depression

February 22, 2011       Rethinking Alarms

November 22, 2011     Perioperative Management of Sleep Apnea Disappointing



What’s New in the Patient Safety World columns:

July 2010                     Obstructive Sleep Apnea in the General Inpatient Population

November 2010           More on Preoperative Screening for Obstructive Sleep Apnea








Roop Kaw R, Pasupuleti V, Walker E et al. Postoperative Complications in Patients With Obstructive Sleep Apnea. Chest 2012; 141(2): 436-441




Memtsoudis S,  Liu SS, Ma Y, et al. Perioperative Pulmonary Outcomes in Patients with Sleep Apnea After Noncardiac Surgery. Anesth Analg 2011; 112: 113-121




Nitsun M. A Simple Way to Screen For Obstructive Sleep Apnea. Outpatient Surgery Magazine. February 2012

















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