TA reports funding from National Institute for Health Research (NIHR), The Royal College of Anaesthetists, The British Journal of Anaesthesia, and Barts Charity; has done consultancy work for MSD, outside of the submitted work; and is a member of the editorial board of the British Journal of Anaesthesia. RP reports grants from NIHR, grants and non-financial support from Intersurgical UK, during the conduct of the study; grants and personal fees from Edwards Life Sciences, outside of the submitted work; and has given lectures or done consultancy work for Nestle Health Sciences, B Braun, Intersurgical, GlaxoSmithKline, and Edwards Lifesciences, and holds editorial roles with the British Journal of Anaesthesia, and the British Journal of Surgery.