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Perioperative Screening for Sleep Apnea

2019; Lippincott Williams & Wilkins; Volume: 129; Issue: 6 Linguagem: Inglês

10.1213/ane.0000000000004412

1526-7598

Stavros G. Memtsoudis, Dennis Auckley,

Airway Management and Intubation Techniques

See Articles, p 1444, p 1673 GLOSSARY ASRA = American Society of Regional Anesthesia and Pain Medicine; OSA = obstructive sleep apnea; PoCUS = perioperative point-of-care ultrasonography; SASM = Society of Anesthesia and Sleep Medicine; STOP-BANG= snoring, tiredness, observed apnea, blood pressure, body mass index, age, neck circumference, and gender Over the past decade, obstructive sleep apnea (OSA) has increasingly been acknowledged by perioperative physicians as a disease entity with major implications within a surgical episode. With an increasing body of evidence suggesting that OSA, especially when untreated,1 represents an independent risk factor for a number of complications,2 expert societies have called for the preoperative identification of individuals suffering from this disease complex.3 Although the evidence for various interventions including positive airway pressure administration and monitoring is evolving,4 significant strides have been made to develop screening tools to identify those at risk for OSA before surgery.3 Faced with limited resources on one side and an overwhelming number of patients with undiagnosed OSA on the other, screening tools such as the now commonly used snoring, tiredness, observed apnea, blood pressure, body mass index, age, neck circumference, and gender (STOP-BANG) questionnaire have been tested and endorsed as easy to use in the perioperative setting.5 However, despite modifications and improvements, this and similar tools are burdened with limited specificity, albeit high sensitivity.6 This means that more patients might screen positive than actually have clinically significant OSA. Because definitive testing for confirmation of the diagnosis of OSA using polysomnography is time consuming and adds significant expense, attempts to increase the accuracy of screening tests in the immediate perioperative setting have become more important than ever. It is in this context that the systematic review by Singh et al7 points to an opportunity to change and improve the perioperative care of patients with OSA by expanding the role of perioperative point-of-care ultrasonography (PoCUS). The authors analyzed data from 21 published studies that investigated various ultrasound-derived measurements and their correlation with OSA. Findings such as the distance between lingual arteries of over 30 mm and mean resting tongue thickness over 60 mm were associated with moderate to good correlation with moderate to severe OSA. Further, dynamic measurements such as tongue base thickness as well as a combination of neck circumference and retro-palatal diameter shortening during a Muller maneuver showed similar results. Nonairway parameters such as carotid artery intimal thickness and the presence of plaque were associated with lower levels of correlation with moderate to severe OSA. The authors conclude that measuring and utilizing these parameters in the perioperative setting might potentially increase the specificity of currently available screening tools. However, this hypothesis remains to be proven with future studies in the perioperative setting. There are some shortcomings of the currently available data, many of which are inherent to meta-analyses and are largely addressed by the authors, although a couple of additional limitations of this body of work are worth mentioning. First, given the range of measurements reported by the different studies, the intra- and interobserver reliability of each measurement, particularly the dynamic measurements, needs to be routinely reported. Further, the determinants used to define OSA, including criteria used to score respiratory events and whether testing was by polysomnogram or home testing, is often not included in the studies and limits the ability to compare results across studies. However, despite these concerns, the findings presented here are pivotal and represent a nidus for future research that may well change the practice of perioperative medicine. Although perioperative clinicians seek to identify patients at high risk for OSA and provide appropriate care for those who need it, there are practical challenges. To be precise, the limited specificity of current screening tests frequently results in an often challengingly large potential pool of patients, which can easily overwhelm the resources of an institution when it comes to implementing suggested prophylactic and monitoring measures.4 This dilemma, however, should not be interpreted as an inadequacy of what otherwise should be considered to be effective and efficient screening tools. It is only in the context of the high prevalence of OSA in the perioperative setting that these tools may be of limited value when trying to identify those most at risk for OSA-related perioperative complications. With definitive testing for OSA in the form of polysomnography being costly and often not available in a timely fashion, any intervention that could meaningfully increase the specificity of current screening approaches, would not only be welcome but would represent a “game changer” in the care of OSA patients. For this to happen, however, a number of steps are required: First, the data presented by Singh et al7 are derived from the nonsurgical literature, and therefore need to be validated among surgical cohorts. Second, the various PoCUS measurements considered for OSA assessment will need to be validated for reliability and consistency across observers, especially those measurements involving dynamic observations. Third, definitions for OSA will need to be consistently reported in future studies to make accurate comparisons to other risk-stratifying tools. And finally, measurements correlating with moderate to severe OSA—levels of severity thought of as drivers of increased perioperative risk—would have to be evaluated in the context of and as supplements to traditional screening tools. In other words, various combinations of measurements and screening test scores need to be studied to evaluate which components can increase specificity sufficiently to be clinically useful. Identifying the most relevant measurements for inclusion in an index will be necessary because obtaining all ultrasound-guided views mentioned in the current review is time consuming and thus impractical. Fortunately, this type of research is not only aspirational but is currently being performed by the author’s group and results are awaited eagerly (ClinicalTrials.gov Identifier: NCT03361553). The presented study, however, is not only of importance because of the basis it provides for advancing the science of OSA research and care, it represents the start of another chapter of the meteoric rise of PoCUS in perioperative medicine. While having its humble beginnings decades ago as a tool to facilitate vascular access placements, it has evolved from a procedure facilitating intervention to one that has encompassed important diagnostic features. PoCUS might be considered among the most impactful disruptive technologies in perioperative medicine of recent years. The ability to rapidly and cost-effectively perform—among others—focused cardiac examinations, evaluate gastric volume, and examine the lung for related pathologies has changed our ability to take care of patients fundamentally by taking our subjective educated clinical assessment and replacing it with more objective certainty based on imaging. The potential role of perioperative PoCUS for the evaluation of patients with possible OSA is yet another example that highlights how important it is to gaze beyond the horizons of our own practice and apply experiences and technologies used by other specialties in ways not traditionally practiced within ours. While neither PoCUS nor OSA screening is a new invention, the amalgamation of the 2 represents an exciting, novel opportunity for researchers and clinicians to chart new territories. Indeed, combining these 2 small jumps may be the only way to achieve the big leap forward and increase the accuracy of screening for OSA. In the words of David Lloyd George: “Don’t be afraid to take a big step if one is indicated. You can’t cross a chasm in two small jumps.” DISCLOSURES Name: Stavros G. Memtsoudis, MD, PhD, MBA, FCCP. Contribution: This author helped write the manuscript. Conflicts of Interest: S. G. Memtsoudis is a director on the boards of the American Society of Regional Anesthesia and Pain Medicine (ASRA) and the Society of Anesthesia and Sleep Medicine (SASM). He has consulted for Sandoz Inc and Teikoku, is on the medical advisory board for HATH and has a pending US Patent for a Multicatheter Infusion System. US-2017-0361063. He is the owner of SGM Consulting, LLC and co-owner of Football Club Monmouth, LLC. None of the above relations influenced the present article. Name: Dennis H. Auckley, MD. Contribution: This author helped write the manuscript. Conflicts of Interest: None. This manuscript was handled by: David Hillman, MD.