For patients with Duchenne muscular dystrophy, active lung volume recruitment may help to preserve vital capacity. Effects on post-plateau vital capacity may be a useful outcome measure for therapeutic trials.

Mechanical insufflation exsufflation-expiratory flows (MIE-EF) correlate with upper airway patency. Patients dependent on continuous noninvasive ventilatory support (CNVS) with severe spinal muscular atrophy type 1, now over 20 years old, have used MIE sufficiently effectively along with CNVS to avoid tracheotomy indefinitely. While MIE-EF can apparently decrease in amyotrophic lateral sclerosis to necessitate tracheotomy, they can increase over time and remain effective in all spinal muscular atrophy types. Two cases demonstrate an association between increasing MIE-EF and ultimately successful decannulation of a continuous tracheostomy mechanical ventilation dependent patient with spinal muscular atrophy type 2 and a patient with obesity hypoventilation syndrome. Only when MIE-EF increased to exceed 200 L/m did the decannulations succeed. Definitive noninvasive management (CNVS) of these patients may only be possible when MIE is effective and the greater the MIE-EF, the greater its effectiveness. Thus, increasing MIE-EF can signal resolution of upper airway obstruction sufficiently to permit decannulation whether a patient is ventilator dependent or not.

Clinicians should attempt to use continuous noninvasive ventilatory support and mechanical insufflation-exsufflation rather than supplemental oxygen to normalize blood gases for neuromuscular ventilatory failure and should be prepared to intubate hypercapnic patients for whom oxygen is administered.