Received: 2 May 2019
Accepted: 21 August 2019
First Online: 6 September 2019
Ethics approval and consent to participate
: This study met UK Health Research Agency criteria for a service evaluation. All the data utilised for this study was routinely collected as part of standard pre-hospital patient data collection. Formal ethical approval was therefore not required as criteria for service evaluation were met.
: Whilst there are no formal competing interests to declare, all authors, except RL, were employed by the trust at the time of publication.