patients (those with BMIs of 40 or higher) have OSA, and 10% to 20%
of those have obesity hypoventilation syndrome. Morbidly obese
patients are also more susceptible to thromboembolic, infectious and
surgical complications, and OSA increases those risks.
• Screen high-risk patients. Identifying high-risk patients for pre-
cautions and interventions can be burdensome, but a growing consen-
sus believes that attempting to do so may reduce complications. For
example, evidence supports avoiding general anesthesia in OSA
patients undergoing specific procedures, such as joint arthroplasty.
Additionally, since OSA can affect respiratory outcomes and promote
post-operative cardiovascular events, it may be wise to consider moni-
toring both cardiac and respiratory function for OSA patients who
have pulmonary hypertension and/or heart disease, both of which are
common comorbidities.
Excessive daytime sleepiness and habitual snoring are classic symp-
toms of undiagnosed OSA patients, but numerous factors also
increase the risk, including alcohol; smoking; obesity; increased neck
circumference; male sex; advanced age; enlarged tonsils, adenoids
and tongues; nasal obstruction; and craniofacial abnormalities.
• Recognize screening's limitations. Sleep testing, such as an
overnight polysomnography, is the only completely accurate way to
diagnose OSA, but because many patients are screened on the day of
surgery, or only a day or 2 before, you'll likely have to rely on ques-
tionnaires or simple clinical models, which aren't 100% accurate.
Among current screening tools, STOP-Bang (osmag.net/fgtkk8) is
the most validated in surgical patients (a score of 4 has a high sensi-
tivity of 88% for identifying patients with severe OSA), and it has also
been validated in sleep clinic patients and the general population. It's
not perfect, but it adds clinical value to the pre-operative assessment
and is a relatively easy way to determine risk. Other screening tools
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