Predictors of mortality in pediatric patients on venoarterial extracorporeal membrane oxygenation.

OBJECTIVES

Currently, there are no established echocardiographic or hemodynamic predictors of mortality after weaning venoarterial extracorporeal membrane oxygenation in children. We wished to determine which measurements predict mortality.

DESIGN

Over 3 years, we prospectively assessed six echo and six hemodynamic variables at 3-5 circuit rates while weaning extracorporeal membrane oxygenation flow. Hemodynamic measurements were heart rate, inotropic score, arteriovenous oxygen difference, pulse pressure, oxygenation index, and lactate. Echo variables included shortening/ejection fraction, outflow tract Doppler-derived stroke distance (velocity-time integral), degree of atrioventricular valve regurgitation, longitudinal strain (global longitudinal strain), and circumferential strain (global circumferential strain).

SETTING

Cardiovascular ICU at Lucille Packard Children's Hospital Stanford, CA.

SUBJECTS: Patients were stratified into those who died or required heart transplant (Gr1) and those who did not (Gr2). For each patient, we compared the change for each variable between full versus minimum extracorporeal membrane oxygenation flow for each group.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN

RESULTS

We enrolled 21 patients ranging in age from 0.02 to 15 years. Five had dilated cardiomyopathy, and 16 had structural heart disease with severe ventricular dysfunction. Thirteen of 21 patients (62%) comprised Gr1, including two patients with heart transplants. Eight patients constituted Gr2. Gr1 patients had a significantly greater increase in oxygenation index (35% mean increase; p < 0.01) off extracorporeal membrane oxygenation compared to full flow, but no change in velocity-time integral or arteriovenous oxygen difference. In Gr2, velocity-time integral increased (31% mean increase; p < 0.01), with no change in arteriovenous oxygen difference or oxygenation index. Pulse pressure increased modestly with flow reduction only in Gr1 (p < 0.01).

CONCLUSION

Failure to augment velocity-time integral or an increase in oxygenation index during the extracorporeal membrane oxygenation weaning is associated with poor outcomes in children. We propose that these measurements should be performed during extracorporeal membrane oxygenation wean, as they may discriminate who will require alternative methods of circulatory support for survival.