Assessing the efficacy of the new protocol for chest compressions before definitive cardiac arrest in emergency medical service-witnessed adult out-of-hospital cardiac arrests.

AIMS: Japanese emergency medical services (EMS) personnel providing advance life support confirm the absence of a carotid pulse before initiating chest compressions (CCs) in adult out-of-hospital cardiac arrest (OHCA). This study aims to investigate the efficacy of a new protocol facilitating early CCs before definitive cardiac arrest in enhancing the outcomes of OHCA.

METHODS: The 2011 new protocol facilitated EMS to initiate CCs when the carotid pulse was weak and/or <50/min in comatose adult patients with respiratory arrest (apnoea or agonal breathing) and loss of the radial pulse. During 2008-2015, we compared the neurologically favourable 1-year survival rate of EMS-witnessed OHCA and EMS-confirmed out-of-hospital respiratory arrest (OHRA) in adults before (N = 257 and 34, respectively) and after (N = 255 and 54, respectively) the implementation of the new protocol.

RESULTS: After the new protocol, EMS initiated CCs >1.5 min before definitive cardiac arrest in 31% (80/255) and 33% (18/54) of EMS-witnessed OHCA and EMS-confirmed OHRA, respectively. While the new protocol was not significantly associated with survival of EMS-confirmed OHRA, it was significantly associated with survival of EMS-witnessed OHCA: 9.0% and 14.9%, before and after, P by univariate analysis <0.03; adjusted OR (95% CI) by multivariable logistic regression analysis, 2.01 (1.04-3.90). Neither early start of CCs nor the new protocol was associated with the progression to cardiac arrest in 212 cases with impending cardiac arrest.

CONCLUSIONS: A new EMS protocol facilitating early CCs before definitive cardiac arrest was associated with higher survival of EMS-witnessed OHCA.