1 North West School of Anaesthesia, Health Education England North West, Liverpool, UK. Electronic address: eleanor.tanqueray@doctors.org.uk.
2 North West School of Anaesthesia, Health Education England North West, Manchester, UK.
3 Lancaster Medical School, Faculty of Health and Medicine, Lancaster, UK; Department of Anaesthesia, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, UK.