Field termination-of-resuscitation rule for refractory out-of-hospital cardiac arrests in Japan.

Background: Guidelines for cardiopulmonary resuscitation (CPR) recommend using the universal termination-of-resuscitation (TOR) rule to identify out-of-hospital cardiac arrest (OHCA) patients eligible for field termination of resuscitation, thus avoiding medically futile transportation to the hospital. However, in Japan, emergency medical services (EMS) personnel are forbidden from terminating CPR in the field and transport almost all patients with OHCA to hospitals. We aimed to develop and validate a novel TOR rule to identify patients eligible for field termination of CPR.

Methods: We analyzed 540,478 patients with OHCA from 2011 to 2015 using a Japanese registry. Main outcome measures were specificity and positive predictive value (PPV) of the newly developed TOR rule in predicting 1-month mortality after OHCA.

Results: Recursive partitioning analysis in the development group (n=434,208) showed that EMS personnel could consider TOR if patients with OHCA met all of the following five criteria: (1) initial asystole, (2) arrest unwitnessed by a bystander, (3) age ≥81 years, (4) no bystander-administered CPR or automated external defibrillator use before EMS arrival, and (5) no return of spontaneous circulation after EMS-initiated CPR for 14min. For patients meeting these criteria, specificity and PPV for predicting 1-month mortality were 99.2% [95% confidence interval (CI), 99.0-99.3%] and 99.7% (95% CI, 99.6-99.7%), respectively, for the development group and were 99.5% (95% CI, 99.3-99.7%) and 99.8% (95% CI, 99.7-99.9%), respectively, for the validation group. Implementation of this novel rule would reduce patient transports to hospitals by 10.6% in the development group and 10.4% in the validation group.

Conclusions: Having both high specificity and PPV of >99% for predicting 1-month mortality, our developed TOR rule may be applied in the field for Japanese patients with OHCA who meet all five criteria. Prospective validation studies and establishment of prehospital EMS protocol are required before implementing this rule.