Point-of-Care Resuscitative Echocardiography Diagnosis of Intracardiac Thrombus during cardiac arrest (PREDICT Study): A retrospective, observational cohort study.

Background: Point-of-care ultrasound (POCUS) has been previously studied in cardiac arrest, without definitive markers for futile resuscitation efforts identified. Intracardiac thrombus during cardiac arrest has not been systematically studied. Our objective was to describe the incidence of intracardiac thrombus and spontaneous echo contrast found during cardiac arrest. Methods: A two hospital, retrospective, observational cohort study of 56 cardiac arrest patients who were assessed with POCUS (between January 1st, 2017 to April 30th, 2020). Eligible studies were reviewed for echocardiographic findings (e.g. presence of intracardiac thrombus or spontaneous echo contrast), baseline patient demographics, cardiac arrest-related data, and clinical outcomes. Primary outcome was in-hospital mortality. Results: Fifty-six intra-arrest POCUS echocardiograms were identified (out of 738 out-of-hospital cardiac arrests). The median patient age was 63 years (interquartile range [IQR]: 51-72), with 25% female patients, and median Charlson Comorbidity Index score of 4 (IQR: 2-6). The incidence of intracardiac thrombus was 21 out of 56 patients (38%). Time-to-new thrombus formation during cardiac arrest was approximately 6 minutes (IQR: 2--8). All patients with intracardiac thrombus during cardiac arrest had termination of resuscitation. Conclusions: Intracardiac thrombus is potentially common during out-of-hospital cardiac arrests and was observed more frequently in those in whom termination of resuscitation was recommended. However, this is only hypothesis-generating at this time, and further study is required to determine if the presence of intracardiac thrombus may be used as a potential marker of resuscitation futility.