Abstract 200: Left-ventricular Outflow Compression During Cardiopulmonary Resuscitation Is Associated With Lower Return Of Spontaneous Circulation In Out-of-hospital Cardiac Arrest

Introduction: Transesophageal echocardiography (TEE) has been proposed as a tool ideally suited for imaging patients during cardiac arrest (CA) resuscitation, allowing for the evaluation of the area of maximal compression (AMC) during CPR. Previous work has shown that compression of the left-ventricular outflow tract (LVOT) or the aortic root during CPR (AMC-LVOT/Ao) occurs in over 50% of patients; animal trials and small single-center retrospective clinical study have linked this finding to lower rates of ROSC. We aimed to prospectively investigate the AMC and its association with ROSC. We hypothesized that patients who have AMC-LVOT/Ao have lower likelihood of ROSC. Methods: A prospective, observational, multicenter cohort study involving patients with out-of-hospital CA (OHCA) in whom TEE was performed during CPR. The study aimed to compare patients with AMC over the LV (AMC-LV) vs AMC-LVOT/Ao and was conducted through a collaborative research network involving 16 hospitals (NCT04972526). Data was collected on clinical and TEE characteristics and findings. Primary outcome was ROSC. We performed univariate analysis followed by multivariate regression model evaluating variables known to impact resuscitation outcomes. Results: Eighty-four patients were included in the analysis. Mean age 62 (46-72), 28% female, 71% had witnessed arrest, 60% had bystander CPR, 47% had mechanical CPR. Overall 26 patients (32%) had ROSC. Initial AMC during CPR was determined in 55/84 (65%) patients, of whom 33 (60%) had AMC-LV, 18 (33%) had AMC-LVOT/Ao, and 4 (7%) had other locations. There was no significant difference in AMC when analyzed by demographic characteristics, height, weight or between patients who received manual vs mechanical CPR. In multivariate regression controlling for age, race, gender, initial rhythm of arrest, level of TEE operator, doses of epinephrine, now-flow time, and total time of arrest, AMC-LVOT/Ao was significantly associated with lower ROSC probability (OR 0.06, 95% CI 0.01-0.4; p=0.009). Conclusion: In this multicenter, prospective study of patients with OHCA, TEE-guided resuscitation showed a strong association between the AMC and ROSC.