Okay, so you finally agree with us that identification of patients at risk for obstructive sleep apnea (OSA) is important when contemplating surgery (see our Patient Safety Tips of the Week for May 22, 2012 “Update on Preoperative Screening for Sleep Apnea” and August 17, 2010 “ ” plus our multiple other columns listed at the end of today’s column). Now what?
We’ve pointed out several times that there is a paucity of evidence-based recommendations for care of surgical patients with suspected or known OSA. The American Society of Anesthesiologists (ASA) practice guidelines for the perioperative management of patients with OSA (ASA 2006) were an important contribution but were written in the era before preoperative screening for OSA became more commonly used and before monitoring standards changed. In addition, it has become apparent that more patients at-risk for OSA are having surgery done on an ambulatory basis. As a result, a couple other groups have stepped up with more up-to-date recommendations for the perioperative management of patients with known or suspected OSA. The Society for Ambulatory Anesthesia published a Consensus Statement on Preoperative Selection of Adult Patients with Obstructive Sleep Apnea Scheduled for Ambulatory Surgery (Joshi 2012). And the American Society of PeriAnesthesia Nurses (ASPAN) published The ASPAN Obstructive Sleep Apnea in the Adult Patient Evidence-Based Practice Recommendation (ASPAN 2012).
Both the guidelines focus on a few key principles in managing patients with suspected OSA:
· Identify at-risk patients
· Determine whether the procedure can be safely done on an ambulatory basis or requires inpatient admission
· Use anesthesia techniques that minimize the risk
· Ensure neuromuscular blockade is completely reversed at the end of procedures
· Ensure safe extubation postoperatively
· Proper positioning (avoiding the supine position)
· Use analgesic approaches that will minimize use of opiates and sedatives
· Monitor appropriately
· Make sure discharge criteria are met
· Educate patient and family on post-discharge risks
· Educate patient and family on further evaluation and management of OSA
The Society for Ambulatory Anesthesia Consensus Statement (Joshi 2012) specifically notes that many of the recommendations are based upon surrogate measures (like oxygen desaturation, need for additional monitoring, etc.) and that there has been no correlation between such surrogate measures and mortality or clinical significant adverse outcomes.
Both the new guidelines recommend screening for OSA but may differ on the tool(s) used. The Society for Ambulatory Anesthesia recommends use of the STOP-Bang questionnaire whereas the ASPAN guideline recommends either the STOP-Bang or the ASA OSA checklist and notes that the Berlin Questionnaire has limited application in the perianesthetic population. Note that in our for May 22, 2012 Patient Safety Tip of the Week “Update on Preoperative Screening for Sleep Apnea” we cited two papers from Frances Chung and her group in Toronto (Chung 2012a, Chung 2012b) that, taken together, suggest a potential strategy for identifying patients with OSA preoperatively without having to do a formal polysomnogram by using the STOP-Bang questionnaire followed by nocturnal oximetry in appropriate cases.
Both new guidelines recommend use of regional techniques (epidural or nerve blocks) and multimodal approaches (eg. NSAID’s, acetaminophen, tramadol, COX2 inhibitors, ketamine, and nonpharmacologic measures) for analgesia in attempt to avoid opiates. If opiates are needed, careful titration is recommended and if PCA is to be used basal opioid infusions should be avoided.
The ASPAN guideline discusses positioning of the patient, recommending the lateral, lateral recumbent or sitting positions and avoidance of the supine position. They note that CPAP or BiPAP used early in the recovery period reduces respiratory effort and may reduce other complications.
Monitoring is obviously critical. In our frequent discussions on monitoring patients receiving opiates we have talked about the pitfalls and false sense of security with pulse oximetry, particularly in patients on supplemental oxygen. Continuous capnography is rapidly becoming the standard for monitoring patients at risk for respiratory depression and those with sleep apnea in the perioperative period. Many facilities have not implemented capnography because of cost concerns. But, interestingly, a post on the Physician-Patient Alliance for Health & Safety (PPAHS) website (see our October 2012 What’s New in the Patient Safety World column “Another PCA Pump Safety Checklist”) showed that for management of surgical patients with OSA implementation of a continuous capnography program in one year resulted in a 70% reduction in operating costs as well as improving patient safety (Wong 2012)!
The ASPAN guideline anticipates a minimum observation period in the PACU of 2-6 hours, on the average 3 hours longer than for non-OSA patients, and it the possibility of more prolonged observation should always be anticipated. Before considering discharge, the patient’s oxygen saturation on room air should have returned to baseline and there should have been no hypoxia or obstruction when the patient is left undisturbed for at least 30 minutes. In addition, for those who do have episodes of obstruction or desaturation the period of observation should be extended for at least an additional 7 hours beyond each such episode. Patients not requiring hi-dose opioids may be considered for discharge home once oxygen saturation is at 94% (or baseline) for at least 2 hours and patient’s level of consciousness has returned to baseline, and the patient is able to use CPAP at home (if previously on CPAP). For patients needing oral opiates discussion should take place between the anesthesiologist and surgeon. Making sure that a responsible adult caregiver be with them overnight after discharge is also advisable.
Patients and their families should be counseled that the increased risk may extend for a few days to as long as a week after surgery. Those already on CPAP need to be educated on the importance of CPAP, which should be used any time the patient sleeps, not just at night. They should also be reminded not to sleep in the supine position. They should also be counseled about not taking excessive doses of analgesics or sedatives, including over-the-counter drugs. For those only suspected of having OSA emphasizing the need to undergo polysomnography testing for confirmation of the diagnosis and then appropriate management is important.
That same October 2012 issue of the Journal of PeriAnesthesia Nursing had a focus on OSA and included several other very useful articles. An Evidence-Based Checklist for the Postoperative Management of Obstructive Sleep Apnea (Gammon 2012) also provides very useful guidelines. It contains most of the recommendations noted in the ASPAN guideline but also includes criteria for extubation of the OSA patient. These include ensuring that the patient is fully awake by following commands, can sustain a head tilt for more than 5 seconds, has a vital capacity greater than 15cc/kg, a negative inspiratory force less than -25 cm H2O, and a respiratory rate greater than 12 per minute. They also recommend putting the patient in a 30 degree reverse Trendelenburg position immediately after extubation.
One study (Setaro 2012), based on a failure mode and effects analysis (FMEA), identified multiple opportunities to improve perioperative management of patients with suspected OSA. One step included in their improved process was to make available results of the screening (STOP) questionnaire on their electronic medical record so it was available to all caring for the patient. Similarly, for handoffs from the OR to the PACU they added OSA as a specific item to their SBAR form. They also developed written educational guidelines to provide the patients at the time of discharge, both for those with known OSA and those with suspected OSA. They required patients with suspected or known OSA to be monitored in the PACU for a minimum of 4 hours after general anesthesia. Patients with prolonged periods of oxygen desaturation would be admitted to monitored inpatient beds. Availability of such inpatient monitored beds was a concern raised but to date had not been problematic. In the first 3 months after implementation of changes they found a 5% increase in identification of patients at high risk for OSA and 2% of high risk patients required admission.
Another (Diffee 2012) had a good discussion on the pathophysiology of OSA and how anesthesia impacts on OSA plus recommendations regarding management. Of note, they point out that inhalational gases and intravenous hypnotics, analgesics, and narcotics all may produce both respiratory depression and airway obstruction that are out of proportion to the level of sedation. This makes the transition from a controlled airway in the OR to spontaneous breathing a particularly unstable period in patients with OSA. Airway problems may first manifest in the PACU after extubation and most airway emergencies occur during the first 24-48 hours postoperatively, noting that the period of REM rebound after perioperative sleep deprivation is also a risky period for OSA respiratory complications. While they emphasize the importance of ensuring compliance with home CPAP prior to surgery, they also note as we have that the evidence base for improvement in outcomes with postoperative use of CPAP is scant (see our November 22, 2011 Patient Safety Tip of the Week “Perioperative Management of Sleep Apnea Disappointing”). They also note that patients at risk for OSA also often have difficult to manage airways and that is an important part of the pre-op evaluation. Because anesthetic effects last into the recovery period they recommend use of local anesthetics, peripheral nerve blocks, spinal or epidural anesthesia, and light-to-moderate sedation rather than general anesthesia where possible. They recommend capnography regardless of type of anesthesia. And they emphasize ensuring full reversal of any neuromuscular blockade before considering extubation. They strongly suggest organizations have written guidelines or protocols for managing patients with known or suspected OSA. They point out that so many procedures today are being performed outside traditional OR’s (eg. in specialty areas) so having those protocols available to all nursing staff is valuable. We concur with that. Even though endoscopy suites, for example, should have the same standards for monitoring all patients we seldom see the same level of surveillance in those areas.
When your screening identifies a patient as being at high risk for OSA you need to decide whether to confirm the diagnosis with polysomnography and begin management prior to surgery. That, of course, usually depends on the urgency of the surgery. If it is elective nonurgent surgery it makes sense to delay the surgery, get polysomnography, get the patient started on CPAP, and maybe even lose some weight if obesity is one of the risk factors for OSA. However, there is little evidence for or against that approach vs. just assuming the patient has OSA and managing him as such.
The next question is usually about the setting in which the surgery is best done. The decision about suitability for ambulatory surgery depends upon patient-related factors, procedure-related factors, and facility-related factors. Among patient-related factors, degree of control of comordities is probably the most important. Because obesity is common in patients with OSA or suspected OSA, many have hypertension, diabetes and coexisting heart disease. In those with known OSA their degree of compliance with home CPAP is important. If they are poorly compliant, they may be expected to be poorly compliant with CPAP postoperatively and may be better managed under surveillance as an inpatient.
Among procedure-related factors the most important is the likelihood that the procedure will require opiates for management of postoperative pain. If it is considered likely that regional anesthesia techniques and non-opioid analgesics (eg. multimodal interventions) can adequately manage post-op pain, then ambulatory surgery may be considered. However, if it is highly likely that post-op opiates will be needed then inpatient admission is advisable.
Among facility-related factors, the most important one is the monitoring capability. These patients need continuous pulse oximetry and capnography. And the ability to perform more extended monitoring and management of patients who do get complications should be another concern.
So, once again, we recommend you consider setting up a screening program for likely OSA prior to scheduled surgery. The STOP-Bang questionnaire is easy to administer in a few minutes and could be done at the time of surgical booking or other time the surgical team contacts the patient. Having a clinical guideline and formal protocols for dealing with those who score high on the STOP-Bang would be wise, keeping in mind that many of those recommendations are still consensus-based rather than evidence-based.
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 “ ”
August 17, 2010 “ ”
July 13, 2010 “Postoperative Opioid-Induced Respiratory Depression”
February 22, 2011 “Rethinking Alarms”
November 22, 2011 “Perioperative Management of Sleep Apnea Disappointing”
May 22, 2012 “Update on Preoperative Screening for Sleep Apnea”
What’s New in the Patient Safety World columns:
November 2010 “More on Preoperative Screening for Obstructive Sleep Apnea”
American Society of Anesthesiologists (ASA). Practice Guidelines for the Perioperative Management of Patients with Obstructive Sleep Apnea. A Report by the American Society of Anesthesiologists Task Force on Perioperative Management of Patients with Obstructive Sleep Apnea. Anesthesiology 2006; 104: 1081–93
Joshi GP, Ankichetty SP, Gan TJ, Chung F. Special Article: Society for Ambulatory Anesthesia Consensus Statement on Preoperative Selection of Adult Patients with Obstructive Sleep Apnea Scheduled for Ambulatory Surgery. Anesth Analg 2012; 115: 1060-1068; published ahead of print August 10, 2012
ASPAN OSA PR Strategic Work Team. The ASPAN Obstructive Sleep Apnea in the Adult Patient Evidence-Based Practice Recommendation. Journal of PeriAnesthesia Nursing 2012; 27(5): 309-315
Chung F, Subramanyam R, Liao P, Sasaki E, Shapiro C, Sun Y. High STOP-Bang score indicates a high probability of obstructive sleep apnoea. British Journal of Anaesthesia 2012; 108 (5): 768–75 (2012)
Chung F, Liao P, Elsaid H, et al. Oxygen Desaturation Index from Nocturnal Oximetry: A Sensitive and Specific Tool to Detect Sleep-Disordered Breathing in Surgical Patients. Anesthesia & Analgesia 2012; 114(5): 993-1000 Published online before print February 24, 2012
Wong M. Improving Hospital Efficiency and Patient Safety: Bedside Monitoring with Capnography Achieves Better Management of Surgical Patients with Obstructive Sleep Apnea. Physician-Patient Alliance for Health & Safety (PPAHS) website. Posted April 5, 2012
Gammon BT, Ricker KF. An Evidence-Based Checklist for the Postoperative Management of Obstructive Sleep Apnea. Journal of PeriAnesthesia Nursing 2012; 27(5): 316-322
Setaro J. Obstructive Sleep Apnea: A Standard of Care That Works. Journal of PeriAnesthesia Nursing 2012; 27(5): 323-328
Diffee PD, Beach MM, Cuellar NG. Caring for the Patient With Obstructive Sleep Apnea: Implications for Health Care Providers in Postanesthesia Care. Journal of PeriAnesthesia Nursing 2012; 27(5): 329-340
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