Time point for transport initiation in out-of-hospital cardiac arrest cases with ongoing cardiopulmonary resuscitation: a nationwide cohort study in Japan

Aim: This study aimed to investigate the time point of the decision to initiate transport with ongoing cardiopulmonary resuscitation (CPR) in Japan. Methods: We analyzed adult out-of-hospital cardiac arrest (OHCA) cases that achieved return of spontaneous circulation (ROSC) before hospital arrival from the All-Japan Utstein Registry during 2015-2017. We constructed receiver operating characteristics (ROC) curves to illustrate the ability of achieving ROSC as a predictor of neurologically favorable outcomes as a function of increasing time points of resuscitation before ROSC. Furthermore, a multivariable logistic regression analysis was carried out to identify factors associated with outcomes. Results: Of 373,993 OHCA patients with attempted resuscitation during 2015-2017, 22,067 patients with prehospital ROSC were included in our study. Patients were divided into the shockable initial rhythm (n = 5,580) and nonshockable initial rhythm (n = 16,487) cohorts. The ROC curves showed 10 min was the best test performance time point for a neurologically favorable outcome for shockable initial rhythm patients (sensitivity, 0.78; specificity, 0.53; area under the ROC curve [AUC], 0.70) and 8 min for nonshockable initial rhythm patients (sensitivity, 0.74; specificity, 0.77; AUC, 0.83). Multivariable logistic regression analyses revealed that CPR durations using the cut-off value were independently associated with better outcomes for both shockable initial rhythm patients (odds ratio, 2.09; 95% confidence interval, 1.81-2.42) and nonshockable initial rhythm patients (odds ratio, 3.34; 95% confidence interval, 2.92-3.82). Conclusion: When Japanese emergency medical service (EMS) providers attend OHCA cases, the decision to initiate transport with ongoing CPR should be made at approximately 10 min after EMS providers initiate CPR for shockable initial rhythm patients and at approximately 8 min for nonshockable initial rhythm patients.