[1] Newcastle Univ, Newcastle Upon Tyne, Tyne & Wear, England
[2] Sunderland Royal Hosp, Sunderland, England
[3] North East Ambulance Serv NHS Fdn Trust, Newcastle Upon Tyne, Tyne & Wear, England
[4] Univ Nottingham, Nottingham, England
[5] James Cook Univ Hosp, Middlesbrough, Cleveland, England
[6] Univ York, Dept Hlth Sci, Clin Trials Unit, York, N Yorkshire, England