Funding for this research was provided by:
National Physical Laboratory (UK), National Measurement System
Received: 26 November 2021
Accepted: 16 March 2022
First Online: 4 April 2022
: Ethical approval was not required for this retrospective study but the use of anonymised patient data was approved by the local hospital’s Information Governance Department.
: Not applicable.
: The authors declare that they have no competing interests.