Patient Safety Tip of the Week


August 18, 2009         Obstructive Sleep Apnea in the Perioperative Period





In recent weeks we’ve had a lot of searches on our site for our articles on obstructive sleep apnea (OSA) in the perioperative period. We’ve done several articles on the hazards of both oxygen therapy and opiate/sedatives in the post-op patient with OSA (see our Patient Safety Tips of the Week for April 8, 2008 “Oxygen as a Medication”, June 10, 2008 “Monitoring the Postoperative COPD Patient”, January 27, 2009 “Oxygen Therapy: Everything You Wanted to Know and More!” and May 12, 2009 “Errors With PCA Pumps”). Unfortunately, OSA is often undiagnosed and unrecognized before postoperative complications occur. Therefore, several groups have attempted to develop screening tools to help identify the OSA patient pre-operatively (see our May 6, 2008 Patient Safety Tip of the Week “Preoperative Screening for Obstructive Sleep Apnea”). Another recent paper (Chung 2009) describes the Berlin Questionnaire, the STOP questionnaire, the STOP-Bang model, the ASA checklist, and other screening tools that may be used for preoperative screening for OSA.


So what do you do when you identify a patient who is a good candidate for OSA and you need to do surgery or an invasive procedure? An excellent article appeared recently in the Journal of Clinical Anesthesia (Bolden 2009) that describes a protocol for perioperative management of OSA used at the MetroHealth Medical Center/Case Western Reserve University School of Medicine in Cleveland.


You’ve often heard us say that the best patient safety lessons begin with stories. Well, the Bolden article begins with 3 case reports, one prior to implementation of the OSA management protocol, one where the protocol was not followed, and one where the protocol was followed. These provide graphic illustrations of the hazards of OSA in the perioperative period. One was an obese patient with recently diagnosed (but not treated) OSA who suffered a fatal cardiopulmonary arrest in the postoperative period after receiving opiates and sedatives and no formal oxygen saturation monitoring. The second was another obese patient with symptoms strongly suggestive of OSA who had refused polysomnography. A procedure was performed under moderate sedation in the radiology suite and the patient then received analgesia via PCA (patient-controlled analgesia) pump on a general nursing unit without monitoring via the OSA protocol. She was found unresponsive and apneic but fortunately was resuscitated and had a good outcome. The third was a patient with OSA managed via the OSA protocol postoperatively in whom the monitoring identified apneic episodes promptly so that appropriate interventions occurred.


The article has a good discussion of OSA and many of the perioperative factors that may accentuate OSA. They note that many of the drugs used during surgery or procedures (anesthetic agents, sedatives, opiates) not only worsen collapse of airways but may also blunt hypoxic and hypercarbic responses. In addition, the supine position that if often needed postoperatively may further aggravate OSA. They go on to discuss the guidelines suggested by both the American Society of Anesthesiologists (ASA) and the American Academy of Sleep Medicine (AASM) and the actual protocol developed at their institution for management of OSA in the perioperative period.


After identifying patients with OSA or at risk for OSA, these patients are admitted to designated beds on regular nursing floors that are equipped with continuous pulse oximeters that alarm both inside and outside the rooms. They stratify the risk based not only on the invasiveness of the procedure being done but also on the severity of the OSA and the likely need for postoperative IV opioids. Their protocol(s) have arms for both documented and undocumented (but suspected) OSA and for those cases where narcotics are likely to be IV or oral. They also have protocols for ambulatory procedures and separate these by whether narcotics are likely to be needed postop. And they give special consideration to patients undergoing tonsillectomy and adenoidectomy, patients who have already had uvulopalatopharyngoplasty, and pediatric patients.


A good recommendation deals with patients who receive CPAP/BiPAP at home. These patients bring their machines with them to the hospital on the day of the schedule procedure. The hospital Clinical Engineering department evaluates the machines before use in the hospital. The protocol(s) also stress use of anesthesia techniques other than general anesthesia where possible (regional or local anesthesia). They also stress the importance of involvement of anesthesiologists in the postoperative management both inside and outside the operating room and PACU because anesthesiologists are more likely to be familiar with choice and titration of the sedative and analgesic medications that may be more optimally used in the OSA patient. Specifically, shorter-acting agents are usually preferred so that there is less drug accumulation that might lead to delayed consequences. The protocol  provides guidance for choosing the site for the procedure to be done, monitoring, the period and venue of observation, and recommendations about discharge home. The article also includes a nice algorhithm that graphically illustrates many of the above recommendations.


The Chung article noted above had a couple additional clinical pearls on the preoperative assessment. They note that difficult intubation is eight times more common in patients with OSA so that appropriate evaluation and contingencies for intubation are important. They also mention that some studies show that CPAP prior to surgery may reduce the rate of serious complications and shorten hospital length of stay.


One other study (Gali 2009) showed a two-phase process to identify patients at higher risk for perioperative respiratory desaturations and complications may be useful to stratify and manage surgical patients postoperatively. In that study a combination of an obstructive sleep apnea screening tool preoperatively (SACS) and recurrent PACU respiratory events was associated with a higher oxygen desaturation index and postoperative respiratory complications.


Perioperative management of the pediatric OSA patient is a bit more complex. An excellent review on this (Schwengel et al 2009) notes that OSA may present differently in young children (eg. more often presenting with failure to thrive or behavior disorders) than in older children and adults. Also, while many of the risk factors for OSA are the same in children and adults, enlargement of the tonsils and adenoids and craniopharyngeal abnormalities are more likely to be predisposing factors for OSA in the pediatric population. They advocate screening all children for OSA and note that “Does your child snore?” remains the most important question since a history of nightly snoring is 91% sensitive for OSA (though only 75% specific). Other questions would deal with observations of restless sleep, nocturnal diaphoresis, behavioral problems, direct observation of apnea or other respiratory abnormalities, and family history of OSA or sudden infant death syndrome (SIDS). Physical examination needs to focus on the airway, especially the nose, pharynx and tongue and look for presence of craniofacial abnormalities (which may both predispose to OSA and present difficulties for intubation). Attention to muscle tone is also important. They have a nice discussion of the cardiopulmonary complications of longer-standing OSA and note when cardiac testing (such as echocardiography) might be important preoperatively. They then have an excellent discussion on pain management and monitoring. An algorhithm is also available in this article.


The Bolden article also highlights the need for all types of providers who are doing moderate sedation anywhere within the health system to be aware of the risks in the OSA patient. So your OSA management protocol should apply not just to patients going through the OR but also those in your endoscopy suites and your radiology area (see last week’s Patient Safety Tip of the Week “The Radiology Suite…Again!”).


All your sites and facilities should have some sort of mechanism for identifying patients who may be at risk for OSA before they have their invasive procedure or moderate sedation and then have in place a protocol like the Case Western one for management of such patients during the post-procedure period.




Update: See our November 2010 What’s New in the Patient Safety World column “More on Preoperative Screening for Obstructive Sleep Apnea






Chung F, Elsaid H. Screening for obstructive sleep apnea before surgery: why is it important?. Current Opinion in Anaesthesiology 2009; 22(3):405-411



Bolden N, Smith CE, Auckley D. Avoiding adverse outcomes in patients with obstructive sleep apnea (OSA): development and implementation of a perioperative OSA protocol. Journal of Clinical Anesthesia 2009; 21(4): 286-293



Gali B, Whelan FX, Schroeder DR, Gay PC, Plevak DJ. Identification of Patients at Risk for Postoperative Respiratory Complications Using a Preoperative Obstructive Sleep Apnea Screening Tool and Postanesthesia Care Assessment. Anesthesiology 2009; 110:869-877



Schwengel DA, Sterni LM, Tunkel DE, Heitmiller ES. Perioperative Management of Children with Obstructive Sleep Apnea. Anesthesia & Analgesia 2009; 109(1):60-75










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