Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.
Abstract and commentary also appear in ACP Journal Club.
For correspondence: Dr S Walker, National Respiratory Training Centre, Warwick, UK.
Source of funding: Garfield Weston Foundation UK.