Clinical paperEvaluation of outcomes after EMS-witnessed traumatic out-of-hospital cardiac arrest caused by traffic collisions
Introduction
Traffic collisions are responsible for approximately 3000 deaths per year in Japan.1 Injury due to traffic collisions is a typical injury mechanism of blunt trauma. The majority of patients with traumatic cardiac arrest (TCA) are young (mean age 39–40 years), male (79%), and injured by blunt mechanisms (67–68%).2 Prognosis of traumatic out-of-hospital cardiac arrest (OHCA) is poor, with reported survival below 3%.3., 4. Various factors affect prognosis; these include the presence or absence of witnesses during the cardiac arrest, rapid emergency medical services (EMS) response, time from onset to cardiopulmonary resuscitation (CPR) or defibrillation, hospital care, and patient demographics, such as age, sex, and comorbidities.5 Previous studies have shown that the prognosis of witnessed TCA is good6; however, detailed information regarding the bystander type is lacking.
In general, if not a trauma patient, patients with cardiac arrest witnessed by EMS exhibit signs and symptoms, such as chest pain, dyspnoea, and changes in vital signs.7 Previous studies excluding non-cardiac causes such as trauma and acute drug overdoses have found that patients whose cardiac arrest was witnessed by paramedics had a higher survival rate from cardiac arrest than those whose cardiac arrest occurred before paramedics arrived.5 Owing to the lack of similar studies in trauma, the prognosis of EMS-witnessed cardiac arrest is unknown. Moreover, previous studies did not compare prognosis based on bystander type.
This study aimed to compare the survival rate of patients with TCA due to traffic collisions who arrested after EMS arrival with that of patients who had witnessed and unwitnessed arrests before EMS arrival. Further, the time from injury to cardiac arrest was assessed.
Section snippets
Study design and setting
This analysis used the Utstein Registry in Japan—a retrospective, nationwide, population-based OHCA registry system and included all patients with TCA caused by traffic collisions between 1 January 2014 and 31 December 2019, who were treated by EMS. Thus, patients with TCA caused by traffic collisions were included in this study. The database was compiled by the Fire and Disaster Management Agency (FDMA) in Japan, and contained all OHCA cases that were transferred to hospitals by EMS personnel.
Participants
Data of 753 933 OHCA patients were recorded between 1 January 2014 and 31 December 2019, of which 14 299 patients had cardiac arrest presumed to be of traumatic origin caused by traffic collisions. A total of 3883 patients with TCA were included in the analysis (Fig. 1).
Of these, 1081 patients had unwitnessed cardiac arrest (unwitnessed group), 2075 patients had cardiac arrest witnessed by a bystander (bystander-witnessed group), and 727 patients had cardiac arrest witnessed by EMS
Discussion
The EMS-witnessed group had a significantly better prognosis than the unwitnessed and bystander-witnessed groups in terms of 1-month survival and prehospital ROSC rates. However, there was no significant difference in good neurological outcome between the three groups. Therefore, we found that witnessing of cardiac arrest by EMS personnel improved the ROSC rate and 1-month survival prognosis but did not affect good neurological outcomes. The median time from injury to cardiac arrest was 18 min.
Limitation
This study had several limitations. First, this study was a retrospective, non-random electronic review of patient care data that were not originally collected for this purpose. Second, many data were missing. Of the 14 299 patients, 8501 (59%) did not respond to prognosis questions. Third, the diagnoses were unknown in the Utstein database used in this study. In addition, trauma severity classifications such as the Abbreviated Injury Scale (AIS) and Injury Severity Score (ISS) were unknown.
Conclusion
To summarise, significantly higher 1-month survival and ROSC rates were observed in patients with EMS-witnessed TCA than in those with unwitnessed and bystander-witnessed TCA. However, there was no significant difference in good neurological outcomes. We found that witnessing of cardiac arrest by EMS increased the ROSC rate and 1-month survival prognosis but did not affect good neurological outcomes. Further, as the median time from injury to cardiac arrest was 18 min, it is desirable to
Conflict of interest
None.
Acknowledgements
The author is grateful for the support of the Graduate School of Health and Sport Science of Nippon Sport Science University. We would like to thank Editage (www.editage.com) for English language editing.
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