Impact of Noninvasive Ventilation on Lung Volumes and Maximum Respiratory Pressures in Duchenne Muscular Dystrophy

BACKGROUND:Duchenne muscular dystrophy (DMD) is a sex-linked genetic disorder in which progressive impairment of skeletal muscle function eventually leads to severe respiratory failure requiring continuous noninvasive ventilation (NIV) at home. A current focus of debate is whether NIV may slow the decline in respiratory function or, on the contrary, worsen respiratory function when started early. Our objective here was to describe the effects of NIV on vital capacity (VC) and maximum respiratory pressures in DMD.METHODS:We analyzed retrospective data from 71 subjects with DMD, including VC, maximum static respiratory pressures, and sniff nasal inspiratory pressure before and after NIV initiation. The declines in these variables from the highest value to the most recent value were computed.RESULTS:Although respiratory function continued to deteriorate over time, NIV introduction was followed by significant slowing in the annual rates of decline in VC (from 4.28 to 1.36 percent predicted), maximum inspiratory pressure (from 2.77 to 1.48 cm H2O), and maximum expiratory pressure (from 2.00 to 1.00 cm H2O). NIV had no effect on sniff nasal inspiratory pressure.CONCLUSIONS:Introducing NIV in subjects with DMD was followed by slowing of the declines in VC and in maximum static inspiratory and expiratory pressures.