Abstract
Mechanical insufflation exsufflation-expiratory flows (MIE-EFs) correlate with upper airway patency. Patients dependent on continuous noninvasive ventilatory support with severe spinal muscular atrophy type 1, now over 20 yrs old, have used MIE sufficiently effectively along with continuous noninvasive ventilatory support to avoid tracheotomy indefinitely. Although MIE-EFs 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 patient with spinal muscular atrophy type 2 who was continuous tracheostomy mechanical ventilation dependent and a patient with obesity hypoventilation syndrome. Only when MIE-EF increased to exceed 200 l/min did the decannulations succeed. Definitive noninvasive management (continuous noninvasive ventilatory support) of these patients may be possible only 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.