What causes suboptimal treatment of obstructive sleep apnea (OSA)?

Updated: Sep 15, 2020
  • Author: Himanshu Wickramasinghe, MD, MBBS; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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Reasons for suboptimal OSA treatment may include the following:

  • Positive airway pressure titration may be insufficient to fully treat OSA and snoring. Research suggests that pressures used to correct OSA and snoring are typically lower than those needed to abolish OSA and snoring. [1] Consider empirically increasing the expiratory pressure by 2 cm H2 O.

  • Once OSA and snoring are treated, patients may be noted to have complex sleep apnea (ie, residual central sleep apneas that do not resolve spontaneously). Complex sleep apnea is beyond the scope of this article.

  • Patients may not be using the positive pressure machine at home sufficiently to obtain adequate benefit to abolish sleepiness during waking hours.

  • A change in medication may have occurred that may decrease arousal from sleep (eg, benzodiazepines), use of alcohol may have changed, or a medication that suppressed rapid eye movement (REM) sleep percentage was discontinued on the titration night, but once stopped, an increase in REM sleep percentage may be correlated with OSA exacerbation (OSA is typically worse in REM sleep).

  • Sildenafil (Viagra) may be increasing the severity of OSA. Sildenafil prolongs the action of cyclic guanosine monophosphate (cGMP) and nitric oxide by inhibiting cGMP-specific phosphodiesterase 5. Nitric oxide promotes upper airway congestion, muscle relaxation, and pulmonary vasodilation and may be the mechanism by which sildenafil exacerbates OSA. [212]

  • A medical disorder that causes excessive sleepiness (eg, hypothyroidism, even if subclinical) may be present.

  • Weight gain may have occurred.

  • The patient may not be complying or may only be partially complying with their CPAP (or BiPAP) device usage. Only rarely do new CPAP devices not have cards that stores data regarding daily positive airway pressure use. All patients in the author’s sleep clinic are encouraged to bring their device with them so the clinicians can download data from their CPAP machine’s data card. Using the device properly and routinely (eg, >5 h per night, >90% of the time) seems necessary to reduce or correct sleepiness.

  • Another sleep disorder known to have hypersomnia as a major presenting symptom (eg, insufficient sleep syndrome, narcolepsy) may be present. Insufficient sleep syndrome is the most common cause of hypersomnia, and OSA is more common among patients who have narcolepsy (a 30% incidence rate vs 1-4% in the population). Consider a diagnosis of sleepiness in addition to OSA (eg, narcolepsy).

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