Early point-of-care focused echocardiographic asystole as a predictive factor for absence of return of spontaneous circulatory in out-of-hospital cardiac arrests: a study protocol for a prospective, multicentre observational study

Introduction Management of out-of-hospital cardiac arrests (OHCAs) in France is performed by a particular prehospital system based on medicalisation of mobile intensive care units composed of an emergency physician and a nurse with all the required devices for advanced care. It follows the European recommendations which advocate for the use of early point-of-care focused echocardiography (EPOCE) in the prehospital setting. An ability of EPOCE may be to predict the absence of return of spontaneous circulation (ROSC) in cases of absence of cardiac motion. We thus intended to investigate this predictive value with a prospective multicentre study. This paper describes the study protocol, while the first patients were recruited in December 2018. Methods ACE is a prospective multicentre (n=8) prognostic study. Briefly, as soon as OHCA is diagnosed and advanced life support (ALS) is initiated, EPOCE will be performed during the automated external defibrillator’ analysis period. The physician will assess detectable motion within the heart and reversible causes of OHCA. However, as the prognostic value of absence of cardiac motion is not currently validated, the results of EPOCE will not be used to withdraw ALS, and the decision to withdraw life support will be done following the European Resuscitation Council recommendations during our study. Analysis The primary endpoint is the positive predictive value of absence of cardiac motion for the absence of final ROSC. The secondary endpoints are predictive characteristics of EPOCE asystole on morbimortality 30 days after OHCA, description of reversible cause and analysis of the EPOCE technique. Ethics and dissemination ACE was approved by an ethical committee (2018-AO1491-54). While ACE is adapted to the French prehospital system, its results will be translatable to other organisations if inter-rater variability is not found. Trial registration number NCT03494153.