[1] Univ Glasgow, Sch Med Dent & Nursing, Glasgow, Scotland
[2] Univ Cambridge, Healthcare Improvement Studies Inst, Cambridge, England
[3] Glasgow Royal Infirm, Intens Care Unit, Glasgow, Scotland
[4] Univ Hosp Crosshouse, Intens Care Unit, Kilmarnock, Scotland
[5] Queen Elizabeth Univ Hosp, Intens Care Unit, Glasgow, Scotland
[6] Univ Hosp Wishaw, Intens Care Unit, Wishaw, N Lanarkshire, Scotland
[7] Victoria Hosp, Intens Care Unit, Kirkcaldy, England
[8] NHS Greater Glasgow & Clyde, Clin Phys, Glasgow, Scotland
[9] Glasgow Royal Infirm, Acad Unit Anaesthesia Crit Care & Perioperat Med, Floor 2,New Lister Bldg,10-16 Alexandra Parade, Glasgow G31 2ER, Scotland