Identifying out-of-hospital cardiac arrest patients with no chance of survival: an independent validation of prediction rules.

BACKGROUND: The Basic life support (BLS) and Advanced life support (ALS) are known prediction rules for termination of resuscitation (TOR) in out-of-hospital cardiac arrest (OHCA). Recently, a new rule was developed by Jabre et al. We aimed to independently validate and compare the predictive accuracy of these rules.

METHODS: OHCA cases in Iceland from 2008-2017 from a population-based, prospectively registered database. Primary outcome was survival to discharge among patients that met all conditions of abovementioned rules: BLS (not witnessed by EMS personnel, no defibrillation nor ROSC before transport), ALS (BLS criteria plus not witnessed nor CPR by bystander) and Jabre (not witnessed by EMS personnel, initial rhythm non-shockable, no sustainable ROSC before third dose of adrenaline).

RESULTS: Overall, 568 OHCA patients were included in validation of TOR rules. Mean age 67, males 74%, witnessed by EMS 11%, by bystander 66% that attempted CPR in 50%, transported to hospital 60%, overall survival 20%. All rules had high specificity for mortality, 99.6-100% (95%CI 95-100). The Jabre and BLS rules had similar sensitivity 47% (43-52) vs. 44% (40-49), respectively, the sensitivity of ALS was lower, 8% (5-11). Combined use of positive BLS and Jabre rules performed the best, identifying 88/226 (39%) of futile cases transported to hospital, specificity 100% (97-100) and sensitivity 59% (55-64).

CONCLUSIONS: The accuracy of the BLS and Jabre TOR rules to predict mortality after OHCA is very good and their combined use may be superior to the use of either one.