1. Department of Targeted Intervention, Centre for Perioperative Medicine, UCL Division of Surgery and Interventional Science, University College London, University of London, London, United Kingdom
2. Health Services Research Centre, National Institute of Academic Anaesthesia, Royal College of Anaesthetists, London, UK
3. Department of Anaesthesia, University College London Hospitals NHS Foundation Trust, London, UK
4. Department of Anaesthesia, Guy’s and St Thomas’ NHS Foundation Trust, London, UK
5. School of Health and Social Care/Adult Nursing & Midwifery Studies, London South Bank University, London, UK
6. National Institute for Health Research Global Health Research Unit on Global Surgery, University of Birmingham, Birmingham, UK
7. King’s College London, University of London, London, UK