Licence information
This article has been accepted for publication in Emergency Medicine Journal, 2019 following peer review, and the Version of Record can be accessed online at http://dx.doi.org/10.1136/emermed-2018-208118. “Reuse of this manuscript version (excluding any databases, tables, diagrams, photographs and other images or illustrative material included where a another copyright owner is identified) is permitted strictly pursuant to the terms of the Creative Commons Attribution-Non Commercial 4.0 International (CC-BY-NC 4.0) http://creativecommons.org BMJ Authors Self-Archiving Policy, September 2018 https://creativecommons.org/licenses/by-nc/4.0/