Early Point-of-care Echocardiography As a Predictive Factor for Absence of Return of Spontaneous Circulatory in Out-of-hospital Cardiac Arrests: a Multicentre Observational Study

Introduction: Early assessment of the prognosis of a patient in cardiac arrest during cardiopulmonary resuscitation is highly challenging. This study aims to evaluate the predictive outcome value of early point-of-care ultrasound (POCUS) in out-of-hospital settings. Methods: This observational, prospective, multicentre study's primary endpoint was the positive predictive value (PPV) of POCUS cardiac standstill within the first 12 min of advanced life support (ALS) initiation in determining the absence of return of spontaneous circulation (ROSC). A multivariate logistic regression model was constructed with adjustments for known predictive variables typically used in termination of resuscitation (TOR) rules. Results: A total of 293 patients were analysed, with a mean age of 66.6 +/- 14.6 years, and a majority were men (75.8%). POCUS was performed on average 7.9 +/- 2.6 min after ALS initiation. Among patients with cardiac standstill (72.4%), 16.0% achieved ROSC compared with 48.2% in those with visible cardiac motions. The PPV of early POCUS cardiac standstill for the absence of ROSC was 84.0%, 95% CI [78.3-88.6]. In multivariable analysis, only POCUS cardiac standstill (adjusted odds ratio [aOR] 3.89, 95% CI [1.86-8.17]) and end-tidal CO2 (ETCO2) value <= 37 mmHg (aOR 4.27, 95% CI [2.21-8.25]) were associated with the absence of ROSC. Conclusion: Early POCUS cardiac standstill during CPR for out-of-hospital cardiac arrest was a reliable predictor of the absence of ROSC. However, its presence alone was not sufficient to determine the termination of resuscitation efforts.