1 Department of Adult Critical Care, Guy's and St Thomas' NHS Foundation Trust, St Thomas' Hospital, 1st Floor East Wing, Lambeth Palace Road, London, SE1 7EH, UK. luigi.camporota@gstt.nhs.uk.
2 Department of Adult Critical Care, Guy's and St Thomas' NHS Foundation Trust, St Thomas' Hospital, 1st Floor East Wing, Lambeth Palace Road, London, SE1 7EH, UK.