A potential termination of resuscitation rule for EMS to implement in the field for out-of-hospital cardiac arrest: An observational cohort study.

INTRODUCTION

Despite international guidelines recommending termination of resuscitation (TOR) rules for out-of-hospital cardiac arrest (OHCA), their implementation remains low. We aimed to develop and validate a new TOR rule that could allow emergency medical service (EMS) personnel to immediately and objectively decide whether to withhold further resuscitation attempts after their arrival.

METHODS

This observational study evaluated data from OHCA cases in a prospectively collected nationwide Utstein-style Japanese database (2008-2012). Patients were divided into a development cohort (2008-2010, n = 342,055) and a validation cohort (2011-2012, n = 247,283). A new TOR was developed based on multivariable logistic regression analysis of factors that were associated with unfavourable neurological outcomes. Validation was performed based on specificity, the positive predictive value (PPV), and the area under the receiver operating characteristic curve (AUC).

RESULTS

Three factors were strongly associated with unfavourable neurological outcomes at one month after OHCA: unshockable initial rhythm (adjusted odds ratio [aOR]: 6.09, 95% confidence interval [CI]: 5.81-6.38), unwitnessed by bystanders (aOR: 5.27, 95% CI: 4.99-5.57), and age of ≥73 years (adjusted OR: 2.34, 95% CI: 2.24-2.45). In the validation cohort, the new TOR rule provided specificity of 0.955 (95% CI: 0.950-0.959), a PPV of 0.996 (95% CI: 0.996-0.997), and an AUC of 0.828 (95% CI: 0.824-0.833).

CONCLUSION

Based on three objective variables: unshockable initial rhythm, unwitnessed by bystanders, and age ≥73 years, which can be collected immediately after the arrival of EMS personnel at the scene, a new TOR can be developed. Our potential new TOR rule provided an excellent PPV (>99%) for unfavourable neurological outcomes at one month after OHCA.