The sleep apnea episode that won’t put you to sleep. Become a sleep apnea guru with incredible insights from Barbara Phillips MD, MSPH, FCCP an expert in pulmonary medicine, critical care and sleep medicine who is also a past president of CHEST! We discuss high-yield topics in the world of obstructive sleep apnea including: home sleep studies vs in-lab polysomnography, the importance of oxygen saturation (the T90 and ODI) when interpreting sleep study results, tricks to improve CPAP adherence, and alternatives therapies for obstructive sleep apnea. ACP members can visit https://acponline.org/curbsiders to claim free CME-MOC credit for this episode and show notes (goes live 0900 EST).
Written and produced by: Cyrus Askin MD
CME questions by: Cyrus Askin MD
Editor: Chris Chiu MD & Matthew Watto MD
Hosts: Cyrus Askin MD & Matthew Watto MD
Guest: Barbara Phillips, MD
Cover-Art & Infographic – Beth Garbitelli, MS1
Dr. Phillips clearly makes the point that OSA is a disease that affects many patients and undiagnosed OSA is a significant public health risk. Diagnosis of OSA, with the emergence of home sleep testing (HST) is easier to achieve than ever and there are many manual and autotitrating CPAP options along with many mask options to better treat patients.
Dr. Phillips mentioned excessive daytime fatigue and morning headaches may be suggestive of underlying sleep apnea. A neck circumference of greater than or equal to 17 inches in males and 16 inches in females is an independent risk factor for OSA. Polycythemia may be seen in patients with OSA, however, this is more indicative of concomitant obesity hypoventilation syndrome as it is suggestive of daytime desaturation events.
Not everyone with OSA is obese or has the metabolic syndrome. Dr. Phillips reminds us that individuals with hypothyroidism, a receding chin, Down syndrome, Treacher-Collins, folks with a genetic predisposition (such as Chinese populations) and post-menopausal women (due to tissue laxity caused by decreased serum estrogen) are all at higher risk for OSA regardless of their BMI.
Although there are indications for inpatient sleep studies, the HST is a great option for many. Lab polysomnography is useful for patients with different pre-existing conditions (see above). However, HST offers certain noteworthy benefits! HST is an inexpensive, fast and easily administered test which uses desaturation events as the primary measurement. The oxygen desaturation index, as well as the T90 (time with oxygen saturation less-than or equal-to 90%) can be determined via an HST and have been shown in the literature to be very useful indicators of disease severity, particularly by the Spanish Sleep Society. Check it! – Consider setting a patient’s auto-titrating CPAP pressure range to 8cm – 16cm H2O as this will capture virtually the full spectrum of potential pressure needs.
The AHI represents the number of times a patient has an episode of complete apnea (stops breathing for 10 or more seconds) + episodes of hypopnea (the definition of which varies) / hour. An AHI < 5 is normal, 6-14 is mild OSA, 15-29 represents moderate OSA and 30+ represents severe OSA. That said, based on data out of the Spanish Sleep Study and other places, the ODI and the T90 may be more clinically useful indicators of disease severity. The ODI represents the number of times oxygen a patient’s oxygen saturation drops from baseline by 4% or more / hour. The T90 which, according to Dr. Phillips, is most predictive of incident cancer and heart disease, is the number of minutes during a night of sleep where the patient’s oxygen saturation is 90% or lower.
Improvements in blood pressure and mortality have been shown or suggested in observational studies with some RCT data from Spain that further supports CPAP use can lead to a statistically significant BP reduction. However, the keys to adherence often lie outside of these findings. Dr. Phillips suggested that motivational interviewing can be the key to helping these patients. If a patient suffers with daytime sleepiness, morning headaches or have a spouse won’t sleep in the same room with them due to loud snoring, focusing on these points may be more useful than raw clinical data. Dr. Phillips also commented on picking the right mask for a patient, i.e. the mask the patient will wear. Thus, she recommends having a patient go online to view different mask options and, if possible, try different options to find the one that will maximize CPAP adherence. In patients without a history of insomnia, Dr. Phillips mentioned that sedative-hypnotic drugs may be helpful in facilitating adherence with CPAP, but there is no evidence to suggest they are useful in those with OSA and insomnia.
Dr. Phillips discussed interventions for OSA other than conventional, non-invasive positive pressure therapy. Mandibular advancement devices, custom made by a dentist, can help with the symptoms of sleep apnea in a patient who is resistant to CPAP. These can be difficult to obtain (i.e. costly and time consuming). Other airway adjuncts, such as those that are commercially available, have not shown to be effective. With respect to surgery, bariatric surgery and tracheostomy certainly can benefit a patient with OSA. Outside of these surgeries, other surgical options do not appear to be as beneficial. Dr. Phillips briefly mentioned medications and in doing so, stated that modafinil does have an FDA-approval for residual sleepiness in patients treated for their OSA with CPAP, but it is not an alternative to CPAP.
OSA is a major medical problem that has significant medical sequelae and a major societal impact. As such, primary care physicians need to be comfortable identifying patients who should be tested for OSA, using strategies to maximize adherence and initiating therapy and managing them over the long term.
By the end of this episode, listeners will appreciate the emerging significance of obstructive sleep apnea (OSA) for primary care providers, who to screen for OSA, how to evaluate patients, and why treatment of OSA is so crucial.
After listening to this episode listeners will…
Dr. Phillips reports no relevant financial disclosures. The Curbsiders report not relevant financial disclosures.
Links from the show are included above. Some additional ones referenced…
– Sleep Heart Health Study: https://sleepdata.org/datasets/shhs
– Spanish Sleep Society (Sociedad Española de Sueño): http://ses.org.es
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