Effects of the Presence of Emergency Medical Service Physician on Neurologically Intact Survival After an Out-of-Hospital Cardiac Arrest: A Nationwide Population-Based Observational Study

Introduction: Previous observational studies have suggested that prehospital emergency medical services (EMS) physician-guided cardiopulmonary resuscitation (CPR) is associated with improved survival after an out-of-hospital cardiac arrest (OHCA) when compared with paramedic-guided CPR. Hypothesis: EMS physician-guided CPR for OHCA is associated with improved 1-month neurologically intact survival compared with paramedic-guided CPR, from the 2010 guideline updates onward. Methods: The study included 613,251 Japanese adults (aged ≥18 years) from a prospectively recorded nationwide Utstein-style database who had OHCA between 2011 and 2015. The patients were divided into two groups on the basis of the presence of a physician during CPR before hospital arrival: EMS physician- (n=19,551, 3.2%) and paramedic-guided CPR groups (n=593,700, 96.8%). The study end-points were 1-month and neurologically intact survivals, defined as Cerebral Performance Category scores of 1 or 2 (CPC 1-2). Results: Proportions of crude 1-month survival and CPC 1-2 in the EMS physician-guided CPR group were significantly higher than those in paramedic-guided CPR group: 10.9% (2138/19,551) vs. 4.8% (28,448/593,700) for 1-month survival and 5.7% (1114/19,551) vs. 2.5% (14,859/593,700) for 1-month CPC 1-2, both p-values <0.0001. Multivariate logistic regression analysis showed that EMS physician-guided CPR was associated with increased adjusted odds ratios (aORs) for 1-month favorable outcomes: 1.70; 95% confidence interval [CI], 1.61-1.79 for 1-month survival; and 1.51; 95% CI, 1.46-1.62 for 1-month CPC 1-2. In the propensity-matched cohort, EMS physician-guided CPR also showed more favorable outcomes 1 month after OHCA than did paramedic-guided CPR: 11.6% (1931/16,612) vs. 7.9% (1310/16,612) for 1-month survival and 6.0% (996/16,612) vs. 4.6% (766/16,612) for 1-month CPC 1-2, both p-values <0.0001 (aOR, 1.68; 95% CI, 1.55-1.82 for survival; and 1.45; 95% CI, 1.30-1.62 for CPC 1-2. Conclusions: This large-scale registry-based study in Japan shows that EMS physician-guided CPR in OHCA before hospital arrival is associated with improved 1-month neurologically intact survival compared with paramedic-guided CPR.