Sean McGuire1, Benjamin Peirce2, Coralie Carle3. 1. Clinical Fellow, Department of Anaesthesia and Intensive Care Medicine, North West Anglia NHS Foundation Trust, Peterborough City Hospital, Peterborough PE3 9GZ. 2. ST5, Department of Anaesthesia and Intensive Care Medicine, North West Anglia NHS Foundation Trust, Peterborough City Hospital, Peterborough. 3. Consultant, Department of Anaesthesia and Intensive Care Medicine, North West Anglia NHS Foundation Trust, Peterborough City Hospital, Peterborough.