Box 1.

Indications for a trial of MPV.

•Vital capacity < 30% predicted •Mask ventilation ≥ 12 h/day •Dyspnoea >2.5 on the Borg scale which is relieved by ventilatory support •Weight loss •Breathlessness eating •Breathlessness with talking and / or loss of voice strength •Weaning from invasive ventilation •Adaptation to any NIV •Daytime hypercapnia, with normal overnight gas exchange on NIV