Fig. 1

Study flow diagram of adult trauma patients who underwent PHEA in the East of England (2015–2022). Cases excluded on interrogation based on mechanism of injury with n = < 10 are grouped to ‘Other’ to protect patient confidentiality and include: smoke inhalation, asphyxiation, electrocution and hypothermia. ‘Training case’ refers to a fictional patient record that was created for the purpose of training and education. PHEA prehospital emergency anaesthesia, SBP systolic blood pressure