Hypercapnia result and eventually hypoxemia also occur. These patients have bulbar weakness. Their ability to generate cough as well as protecting airways from aspiration of food and saliva. Patients with neuromuscular disorders also have higher incidence of sleep-disordered breathing from obstructive and central sleep apneas. Expiratory muscle aids can help with coughing.
Goals is to avoid nightime hypercapnia and desaturation.
Contraindication to nonivasive respiratory muscle aids include inadequate oropharyngeal muscle for swallowing or controlling saliva without aspiration.