title: Authors' reply.
authors.forename: Helmy
authors.initials: H
authors.lastname: Haja Mydin
authors.forename: Stephen
authors.initials: S
authors.lastname: Murphy
authors.forename: Howell
authors.initials: H
authors.lastname: Clague
authors.forename: Kishore
authors.initials: K
authors.lastname: Sridharan
authors.forename: Ian K
authors.initials: IK
authors.lastname: Taylor
mesh_terms: D000740:Anemia; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000097:blood*; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive; D012131:Respiratory Insufficiency