Clinical paperPhysician’s presence in pre-hospital setting improves one-month favorable neurological survival after out-of-hospital cardiac arrest: A propensity score matching analysis of the JAAM-OHCA Registry
Introduction
Sudden cardiac arrest is one of the major public health issues in the developed countries.1., 2., 3., 4., 5. Approximately 80,000 out-of-hospital cardiac arrests (OHCAs) of cardiac origin occur every year in Japan.6 The time taken to start the treatment after occurrence of an OHCA is a major predictor of resuscitation success.7., 8., 9., 10., 11. It is known that a witnessed cardiac arrest event favors a faster rescue, especially if accompanied by early cardiopulmonary resuscitation (CPR) initiated by lay persons on the scene.12., 13. However, despite recurrent updates of CPR guidelines and the spread of the “chain-of-survival”, OHCA survival remains very low.6., 14., 15., 16.
In many countries, pre-hospital physicians are an integral part of emergency medical services (EMS) teams and are often dispatched to the most severe cases, including cardiac arrest.17., 18., 19., 20. Additionally, the number of ambulances and emergency helicopters with pre-hospital physicians has been increasing rapidly in some areas in Japan.20., 21. Furthermore, the number of pre-hospital dispatches of physicians to emergency scenes doubled in the five years from 2011 to 2016.20 The Japanese emergency helicopter service is modeled on the German air ambulance system.21 Several papers have demonstrated that the presence of a pre-hospital physician was significantly associated with improved outcome after OHCA.17., 18., 19. However, the effectiveness of pre-hospital physicians is a controversial subject, due to the inclusion of unadjusted in-hospital treatments in statistical analysis.18., 22. Optimal post-return of spontaneous circulation treatments may improve OHCA patients’ outcomes more powerfully than a pre-hospital physician’s presence.23., 24.
The data of in-hospital treatments for OHCA patients were prospectively collected in the Japanese Association for Acute Medicine (JAAM)-OHCA Registry, such as extracorporeal membrane oxygenation (ECMO), percutaneous coronary intervention (PCI), intra-aortic balloon pumping (IABP), and targeted temperature management (TTM).25., 26. We believe the additional statistical analysis that takes into account “in-hospital treatments” such as those provided in intensive care units, is required in order to understand the real effectiveness of pre-hospital physicians’ presence. Using the JAAM-OHCA Registry after adjusting for in-hospital treatments, we evaluated the effectiveness of physicians’ presence in pre-hospital settings compared with their absence.
Section snippets
Study design, population, and setting
This study was a retrospective analysis of the JAAM-OHCA Registry.25., 26. We analyzed OHCA patients who were at least 18 years of age, whose collapse was of medical etiology, and who were treated in participating institutions after being transported by EMS personnel, from 1 June 2014 through 31 December 2017. The patients whose data on pre-hospital care were missing were excluded from the analysis.
Cardiac arrest was defined as the cessation of cardiac mechanical activity confirmed through the
Results
A total of 34,754 patients who had an OHCA during the study period were documented. After the exclusion of 833 patients upon whom resuscitation attempts were not made at the hospital, 3065 patients with unknown data on pre-hospital care, 11,359 patients with non-medical causes for the OHCA, and 250 patients less than 18 years old, 19,247 individuals were eligible for analysis. Among them, 2,186 (11.4%) had received resuscitation by a pre-hospital physician and 17,061 (88.6%) had not (Fig. 1).
Discussion
Since its inception, the JAAM-OHCA Registry in Japan has been confirmed as being a large real-world database that enables the evaluation of the effectiveness of physicians' presence in pre-hospital settings during OHCA, and during that time the number of nationwide participating hospitals, including critical care medical centers, and the duration of data collection have increased. After adjusting for in-hospital treatment factors, a positive association was observed between a physician's
Limitations
There are several limitations in this study. First, as in previous observational studies, unmeasured confounding factors may have influenced the association between physicians on the scene and patient outcomes. We were unable to assess several important factors: quality of CPR, including chest compression, performed by bystanders, EMS personnel, pre-hospital physicians, and medical staff in the hospital; bystanders’ characteristics, including age, sex, weight, and experience with basic life
Conclusions
Using the JAAM-OHCA Registry, we found that the one-month favorable neurological survival after an OHCA was significantly associated with pre-hospital physicians’ presence.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
We are deeply indebted to all members and institutions of the JAAM-OHCA Registry for their contribution. The participating institutions of the JAAM-OHCA Registry are listed at the following URL: http://www.jaamohca-web.com/list/. We also thank Dr. Takashi Sano of Jichi Medical University for statistical consultation. We would like to thank NAI (https://www.nai.co.jp) for English language editing.
Funding
This study was supported by research funding from the JAAM and scientific research grants from the Ministry of Education, Culture, Sports, Science and Technology of Japan (grant numbers 16K09034, 15H05006, 17K11572, and 19K18351).
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