[1] Cardiothoracic Surgery, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, Headley Way
[2] Bradford Royal Infirmary, Bradford, West Yorkshire, BD9 6RJ, Duckworth Lane
[3] James Cook University Hospital, Middelsbrough, TS4 3BW, Marton Road
[4] Cleveland School of Anaesthesia, James Cook University Hospital, Middlesbrough, TS4 3BW, Marton Road