Received: 24 May 2020
Accepted: 28 May 2020
First Online: 9 June 2020
Ethics approval and consent to participate
: Research ethics committee approval was not required for this study as per the UK Health Research Authority Decision tool (ExternalRef removed). Due to the retrospective nature of the study, the local institutional board (Oxford University Hospitals NHS Foundation Trust Research and Development) approved ethical oversight and waiver of consent. No direct patient identifiable data were collected.
: Not applicable