Footnotes

• Handling editor Edward Carlton

• X @DrTomRoberts

• Contributors AA and TR came up with the concept and design of this work. KR conducted detailed data collection. TR was responsible for the analysis. All authors were responsible for the submitted manuscript.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests TR is not employed at NHCT. Due to an interest in the conservative management of traumatic haemothoraces, TR and AA formed an academic collaboration to explore the observational approach being used at NHCT.

• Provenance and peer review Not commissioned; externally peer reviewed.