Advertisement

Sleep Apnea: Problems and Solutions

      Graphical abstract

      Sleep-disordered breathing is a common but underrecognized problem in the post-acute and long-term care (PALTC) setting, with an estimated prevalence of 25% to 50%. It’s also common in patients with congestive heart failure (CHF) — with either reduced or preserved ejection fraction — and it worsens with both CHF exacerbation and the progression of CHF severity.
      Likewise, patients who have both CHF and sleep-disordered breathing fare worse than those without sleep apnea, said Julie Gammack, MD, CMD, at the annual conference of AMDA — The Society for Post-Acute and Long-Term Care Medicine.
      Particularly in the case of central sleep apnea (CSA), the predominant form of sleep-disordered breathing in individuals with more severe CHF, “the sympathetic surges that happen when people breathe and then don’t breathe, and when their CO2 rises and then falls rapidly, is thought to affect cardiac output, cardiac remodeling, and potentially relate to arrhythmia,” said Dr. Gammack, a professor of medicine in the Division of Geriatric Medicine at Saint Louis University in Missouri.
      Arrhythmias are believed to be quite common in patients with CSA, she emphasized. Unfortunately, she said, it appears that treatment of CSA with bilevel positive airway pressure (BiPAP) may worsen CHF, at least in patients with a low ejection fraction.

      BiPAP versus CPAP

      Unlike continuous positive airway pressure (CPAP) devices, which deliver fixed, continuous, positive airway pressure, BiPAP devices have two settings — a higher inspiratory pressure and a lower expiratory pressure — which often makes them more tolerable for those who find exhaling against high CPAP pressure uncomfortable. The most sophisticated type of BiPAP device — the BiPAP with a backup rate — uses adaptive servoventilation and delivers variable inspiratory support during hypopnea and mandatory breaths during apnea. During periods of hyperventilation, the support is reduced.
      Among the studies that have looked at CSA and various types of mask-based positive airway pressure in patients with CHF and reduced ejection fraction, CPAP improved sleep-disordered breathing, left ventricular ejection fraction, and the 6-minute walk test distance, among other measures, without any survival benefit. BiPAP with a backup rate, however, reduced sleep-disordered breathing and offered other benefits, but it was associated with a significantly higher all-cause mortality.
      “Why wouldn’t the improvement in breathing help? There are a few thoughts — that [the device worsened] the sympathetic surges that happen as breathing happens, that apneic spells are somehow adaptive, or that there’s some inherent toxicity of PAP,” Dr. Gammack said.
      In patients with CHF and preserved ejection fraction, research has suggested improved cardiovascular outcomes with BiPAP. Those studies have been small, however, with no randomized controlled trial as in the population with reduced ejection fraction. “So we really don’t know,” Dr. Gammack said. For now, a CHF diagnosis, particularly with reduced ejection fraction, is a potential contraindication for BiPAP treatment.

      Medical Interventions

      Acetazolamide and theophylline have been touted “as potential ways to induce respiration” in patients with CSA and CHF, but the studies have been small and suggested an increased risk of arrhythmias, possibly stemming from “the metabolic acidosis changes that are induced by these medications,” Dr. Gammack said. At this point, “medication management is not recommended in patients with CHF.”
      Newer implantable devices for sleep-disordered breathing are emerging — phrenic nerve stimulation for CSA and hypoglossal nerve stimulation for obstructive sleep apnea (OSA), Dr. Gammack noted. “We may be taking care of folks who come to us with these devices, so we need to know about them,” she said.
      Phrenic nerve stimulation aims to induce smooth diaphragmatic contraction and has been shown to improve central respiratory depression events, but there have been serious adverse events in 10% of patients, “mainly related to the implanting of the leads,” Dr. Gammack said. Hypoglossal nerve stimulation provides apnea-induced stimulation and “does show some benefit in reducing apneic events, but again, there are unknown cardiovascular outcomes.”

      Diagnosis

      CSA involves dysregulation in the brainstem respiratory centers and often presents as a Cheyne-Stokes respiratory pattern, with repeating periods of hyperventilation followed by hypoventilation. Individuals with CHF and CSA may often have an obstructive component to their sleep-disordered breathing as well, Dr. Gammack noted.
      Sleep testing is required to diagnose CSA and OSA. Home sleep apnea testing is convenient, accessible, and comfortable, but is not as accurate as sleep-center testing, particularly for CSA. Still, it can be performed in the PALTC setting, and it “may be the more reasonable approach if we were to embark on a sleep study to understand if an individual has CSA or OSA.”
      Oxygen qualification testing for patients with chronic lung disease and OSA — or other qualifying conditions — may also be done in the skilled nursing setting, Dr. Gammack emphasized.
      “It’s nice to know that whether we’re testing for ‘at-rest,’ ‘awake and exercising,’ or ‘during sleep’ qualification categories, the skilled nursing facility is considered an acceptable site,” she said. For post-acute patients, she noted that knowing how to do secure oxygen qualification “can allow our patients to transition as seamlessly as possible.”
      When supplemental oxygen is needed for patients with chronic lung disease and OSA, qualification requires two steps. “It has to be done in a sleep setting where you optimize your CPAP and then [demonstrate the need for oxygen],” she said.
      Christine Kilgore is a freelance writer in Falls Church, VA.