1. Edinburgh Critical Care Research Group, Department of Critical Care, Royal Infirmary of Edinburgh, Edinburgh, UK
2. Department of Critical Care, Royal Infirmary of Edinburgh, Edinburgh, UK
3. Department of Critical Care, Victoria Hospital Kirkcaldy, Kirkcaldy, UK
4. Department of Critical Care, St John’s Hospital, Livingston, UK
5. Department of Critical Care, Western General Hospital, Edinburgh, UK
6. Department of Critical Care, Borders General Hospital, Melrose, UK