Imperial College London, University of East London - Department of Computer Science, NHS Grampian - Department of Anaesthesia and Critical Care, Royal Brompton Hospital - Department of Heamatology, Royal Brompton and Harefield NHS Foundation Trust, Royal Brompton Hospital - Medical Statistician, University Hospitals of Leicester - Department of Anaesthesia and Critical Care, Royal Papworth Hospital - Department of Anaesthesia and Critical Care, Royal Papworth Hospital - Department of Anaesthesia and Critical Care, NHS Grampian, Imperial College London - Department of Haematology, Royal Brompton Hospital - Department of Anaesthesia and Critical Care, Royal Papworth Hospital - Department of Anaesthesia and Critical Care, Royal Papworth Hospital and University Hospitals of Leicester - Department of Anaesthesia and Critical Care