Effects of varying blood flow rate during peripheral veno-arterial extracorporeal membrane oxygen (V-A ECMO) on left ventricular function measured by two-dimensional strain.

Background: We evaluated the effects of varying blood flow rate during peripheral veno-arterial extracorporeal membrane oxygen (V-A ECMO) on left ventricular function measured by two-dimensional strain. Methods: Adult patients who were supported by peripheral V-A ECMO were recruited. Serial hemodynamic and cardiac performance parameters were measured by transthoracic echocardiogram within the first 48 h after implementation of V-A ECMO. Measurements at 100%, 120%, and 50% of target blood flow (TBF) were compared. Results: A total of 54 patients were included and the main indications for V-A ECMO were myocardial infarction [32 (59.3%)] and myocarditis [6 (11.1%)]. With extracorporeal blood flow at 50% compared with 100% TBF, the mean arterial pressure was lower [66 ± 19 vs. 75 ± 18 mmHg, p < 0.001], stroke volume was greater [23 (12-34) vs. 15 (8-26) ml, p < 0.001], and cardiac index was higher [1.2 (0.7-1.7) vs. 0.8 (0.5-1.3) L/min/m2, p < 0.001]. Left ventricular contractile function measured by global longitudinal strain improved at 50% compared with 100% TBF [-2.8 (-7.6- -0.1) vs. -1.2 (-5.2-0) %, p < 0.001]. Similarly, left ventricular ejection fraction increased [24.4 (15.8-35.5) vs. 16.7 (10.0-28.5) %, p < 0.001] and left ventricular outflow tract velocity time integral increased [7.7 (3.8-11.4) vs. 4.8 (2.5-8.5) cm, p < 0.001]. Adding echocardiographic parameters of left ventricular systolic function to the Survival After Veno-arterial ECMO (SAVE) score had better discriminatory value in predicting eventual hospital mortality (AUROC 0.69, 95% CI 0.55-0.84, p = 0.008) and successful weaning from V-A ECMO (AUROC 0.68, 95% CI 0.53-0.83, p = 0.017). Conclusion: In the initial period of V-A ECMO support, measures of left ventricular function including left ventricular ejection fraction and global longitudinal strain were inversely related to ECMO blood flow rate. Understanding the heart-ECMO interaction is vital to interpretation of echocardiographic measures of the left ventricle while on ECMO.

Predictors of Favorable Neurologic Outcomes in a Territory-First Extracorporeal Cardiopulmonary Resuscitation Program.

Extracorporeal cardiopulmonary resuscitation (ECPR) is an advanced resuscitation method that has been associated with better outcomes after cardiac arrest compared with conventional cardiopulmonary resuscitation. This is a retrospective analysis of all patients who received ECPR for cardiac arrest in Hong Kong's first ECPR program from 2012 to 2020. The primary outcome was favorable neurologic outcome at 3 months. A new risk prediction model was developed and its performance was compared with published risk scores. One-hundred two patients received ECPR and 19 (18.6%) patients survived with favorable neurologic outcome. Having a shockable rhythm was the strongest predictor of favorable neurologic outcome in multivariate analysis (odds ratio, 9.64; 95% confidence interval [CI], 1.49 to 62.30; P = 0.017). We developed a simple model with three parameters for the prediction of favorable neurologic outcomes - presence of shockable rhythm, mean arterial pressure after extracorporeal membrane oxygenation, and the Acute Physiology And Chronic Health Evaluation IV score, with an area under receiver operating characteristic curve of 0.85 (95% CI, 0.77 to 0.94). In Hong Kong's first ECPR program, 18.6% patients survived with favorable neurologic outcomes, and having a shockable rhythm at presentation was the strongest predictor. Risk scores are useful in predicting important patient outcomes and should be included in clinical decision-making for patients who received ECPR.