Sleep-disordered Breathing in Neuromuscular Disease

Abstract

Sleep-disordered breathing in neuromuscular diseases is due to an exaggerated reduction in lung volumes during supine sleep, a compromised physiologic adaptation to sleep, and specific features of the diseases that may promote upper airway collapse or heart failure. The normal decrease in the rib cage contribution to the tidal volume during phasic REM sleep becomes a critical vulnerability, resulting in saw-tooth oxygen desaturation possibly representing the earliest manifestation of respiratory muscle weakness. Hypoventilation can occur in REM sleep and progress into non-REM sleep, with continuous desaturation and hypercarbia. Specific characteristics of neuromuscular disorders, such as pharyngeal neuropathy or weakness, macroglossia, bulbar manifestations, or low lung volumes, predispose patients to the development of obstructive events. Central sleep-disordered breathing can occur with associated cardiomyopathy (e.g., dystrophies) or from instability in the control of breathing due to diaphragm weakness. Mitigating factors such as recruitment of accessory respiratory muscles, reduction in REM sleep, and loss of normal REM atonia in some individuals may partially protect against sleep-disordered breathing. Noninvasive ventilation, a standard-of-care management option for sleep-disordered breathing, can itself trigger specific sleep-disordered breathing events including air leaks, patient-ventilator asynchrony, central sleep apnea, and glottic closure. These events increase arousals, reduce adherence, and impair sleep architecture. Polysomnography plays an important role in addressing pitfalls in the diagnosis of sleep-disordered breathing in neuromuscular diseases, identifying sleep-disordered breathing triggered by noninvasive ventilation, and optimizing noninvasive ventilation settings.

Diaphragm Dysfunction: Diagnostic Approaches and Management Strategies

“…In the presence of more severe diaphragm paresis or in patients with underlying obesity or cardiorespiratory diseases, orthopnea, dyspnea when bending forward, coughing, chest pain and dyspnea on exertion may become evident [85,86,87,88], as can symptoms of sleep-disordered breathing [88,89]. In contrast, patients presenting with bilateral diaphragm weakness very frequently report severe dyspnea when supine and during exertion [87,90,91,92,93] and are likely to show features of sleep-disordered breathing [37,94,95,96,97]. In all cases, a careful evaluation is required to try to identify the etiology of diaphragm weakness, and clinical testing is required to confirm the presence and the severity of the disease.…”

Tele-monitoring of ventilator-dependent patients: a European Respiratory Society Statement

“…Although CPAP and NIV may reverse events and can improve survival and quality of life in hypoventilation and nocturnal desaturation in NMD, and in patients with hypoventilation syndromes [79,87], abnormalities may occur at night, such as air leaks, ventilator-patient asynchrony, central events, and glottic closure leading to desaturations, arousals, impaired sleep architecture, and poor adherence. Polysomnography using conventionally available parameters is an important tool for accurately establishing the device setting avoiding these abnormalities.…”

Currents issues in cardiorespiratory care of patients with post-polio syndrome

“…Although overnight EtCO2 provides valuable information concerning nocturnal hypoventilation, it is recommended that suspected sleep dysfunction in neuromuscular disorders be investigated with full-night in-laboratory polysomnography (PSG) 32 . This tool is valuable both for the diagnosis and treatment adequacy, since it allows the noninvasive positive pressure titration to determine an effective level of nocturnal ventilatory support in patients with chronic alveolar hypoventilation, and/or sleep disturbances 33 .…”