Timing and Identification of the Cause and Treatment of a Cardiac Arrest: A Potential Survival Benefit

Objective: The aim of this study was to evaluate how mobile medical teams (MMTs) search for the etiology of a cardiac arrest (CA) and to investigate the association between the discovery of etiology and patient outcome. Subjects and Methods: Resuscitations of all adult patients who experienced an in- or out-of-hospital CA between 2016 and 2018 were video recorded. All video recordings were reviewed. The time to start of "cause analysis" and time to treatment by the MMT were analyzed. Also, investigations performed during etiologic evaluation were examined: heteroanamnesis, medical history-taking, clinical examinations, technical investigations, and the use of the 4Hs and 4Ts method. Results: Of the 139 CA events included in this study, the MMTs performed etiologic evaluation in only 75% of the resuscitations, and in 20% of the evaluations, they did not use the recommended 4Hs and 4Ts method. Medical history-taking and heteroanamnesis were performed in the large majority, but often without clear cause. A presumptive etiology was found in 46.8% of out-of-hospital CAs and 65.2% of in-hospital CAs. A significant association was found between return of spontaneous circulation and the discovery of presumable etiology for out-of-hospital CAs (p < 0.001). The median time to treatment was 492 s (recommended: 130-250 s) for nonshockable rhythms and 422 s (recommended: 270-390 s) for shockable rhythms, up to twice the time advised according to the guidelines. Conclusion: The current approach for etiologic evaluation is not ideal. Further research is needed to establish a more structured and simplified approach.