A standard operating procedure for prehospital anaesthesia and its effect on mortality-An observational study.

Background: Prehospital anaesthesia is a complex intervention performed for critically ill patients. To minimise complications, a standard operating procedure (SOP) outlining the process is considered valuable. We investigated the implementation of an SOP for prehospital anaesthesia in helicopter emergency medical services (HEMS).

Methods: We performed a retrospective observational study of patients receiving prehospital anaesthesia by Finnish HEMS from January 2012 to August 2019. The intervention studied was the implementation of an SOP at two of the five bases during 2015-2016. Patients were stratified according to whether they were anaesthetised before, during or after implementation and the primary outcomes were 1- and 30-day mortality. Secondary outcomes included anaesthesia quality indicators. Confounding factors was assessed via logistic regression.

Results: A total of 3902 tracheal intubations were performed without an SOP, 430 during implementation and 1525 after implementation. The SOP had a significant effect on 1-day mortality during implementation with an odds ratio (OR) of 0.56, 95% confidence interval (95% CI) 0.37-0.81 and a further trend towards benefit after implementation (OR 0.84, 95% CI 0.68-1.04), but no difference in 30-day mortality (OR after implementation 1.10, 95% CI 0.92-1.30). Implementation of an SOP improved first-pass success rate from 87.3% to 96.5%, p < 0.001.

Conclusion: Implementation of an SOP for prehospital anaesthesia was associated with a trend towards lower 1-day mortality and an improved first-pass success but did not affect 30-day mortality. Despite this, we advocate prehospital systems to consider implementation of a prehospital anaesthesia SOP as immediate performance markers improved significantly.