title: Authors' reply.
authors.forename: Patrick B
authors.initials: PB
authors.lastname: Murphy
authors.forename: Kate
authors.initials: K
authors.lastname: Brignall
authors.forename: John
authors.initials: J
authors.lastname: Moxham
authors.forename: Michael I
authors.initials: MI
authors.lastname: Polkey
authors.forename: A Craig
authors.initials: AC
authors.lastname: Davidson
authors.forename: Nicholas
authors.initials: N
authors.lastname: Hart
mesh_terms: D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000628:therapy*; D008168:Lung / Q000503:physiopathology*; D008297:Male; D063087:Noninvasive Ventilation; D029424:Pulmonary Disease, Chronic Obstructive / Q000628:therapy*; D012121:Respiration, Artificial / Q000379:methods*