title: The authors reply.
authors.affiliation: Department of Critical Care, University of Edinburgh, Royal Infirmary Edinburgh, Edinburgh, Midlothian, United Kingdom; Centre for Population Health Sciences, Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, United Kingdom; Department of Critical Care, University of Edinburgh, Edinburgh, Scotland, United Kingdom; Centre for Population Health Sciences, Usher Institute of Population Health Sciences and Informatics, University of Edinburgh Department of Critical Care, University of Edinburgh, Edinburgh, Scotland, United Kingdom.
authors.forename: Annemarie Beth
authors.initials: AB
authors.lastname: Docherty
authors.forename: Niall H
authors.initials: NH
authors.lastname: Anderson
authors.forename: Timothy Simon
authors.initials: TS
authors.lastname: Walsh
authors.forename: Nazir I
authors.initials: NI
authors.lastname: Lone