Mechanical in-exsufflation improves the breathing pattern in patients with duchenne muscular dystrophy

With the progression of Duchenne Muscular Dystrophy (DMD), muscular weakness affects also respiratory muscles compromising cough, a fundamental mechanism that allows to clear the airway preventing chest infections. Mechanical insufflation-exsufflation is a therapy in which the lung is alternatively inflated and deflated using positive and negative pressures respectively, simulating a natural cough and allowing to move secretions. Several studies reported that the use of cough assistive devices helps to prevent infection and decreases episodes of respiratory failure. It is well accepted that mechanical in-exsufflation increases cough peak flow but there is a little information on how breathing pattern is affected by this kind of therapy; therefore further investigation is needed. In this study, 15 patients with DMD, using in-exsufflation device regularly at home, were enrolled and received a single inexsufflation treatment. Quiet breathing before and after treatment was analyzed and total and compartmental chest wall (CW) volumes were measured by Opto-Electronic Plethysmography. Data show changes in breathing pattern parameters resulting in an increased ribcage tidal volume, and decreased breathing rate. This modification in the ventilatory strategy may help to improve lung volume recruitment and optimize gas exchanges within the alveoli. Further experiments are needed to verify the long-term effect of this procedure.