Pneumothorax associated with mechanical insufflation-exsufflation and related factors.

Impaired cough that results in ineffective airway secretion clearance is an important contributor to pulmonary complications in patients with neuromuscular weakness including spinal cord injury. Mechanical insufflation-exsufflation (MI-E) is a respiratory aid used by patients with weak respiratory muscles to increase cough peak flows and improve cough effectiveness. Relative contraindications to MI-E are said to include susceptibility to pneumothorax, but the association of pneumothorax with MI-E use has never before been described. We report two cases of pneumothorax in patients with respiratory muscle weakness associated with daily use of MI-E: one was a 58-yr-old male with C4 ASIA C tetraplegia, and the other was a 26-yr-old male with Duchenne muscular dystrophy. Both patients also used positive-pressure ventilatory assistance. Although seemingly rare in this patient population, ventilator users also using MI-E who have increasing dyspnea or who require increasing positive inspiratory pressures when using noninvasive ventilation should be evaluated for pneumothorax.