What should be done for a patient on Venovenous-Arterial (VAV) Extracorporeal Membrane Oxygenation (ECMO) who has lost pulsatility?

From the Guidelines

For a VAV ECMO patient who has lost pulsatility, you should immediately assess for cardiac standstill and notify the ECMO team or cardiac surgeon, and increase ECMO flow to maintain end-organ perfusion while reducing the risk of intracardiac thrombus formation, as recommended by recent studies 1. The loss of pulsatility in a VAV ECMO patient is a critical situation that requires prompt attention. The first step is to assess for cardiac standstill and notify the ECMO team or cardiac surgeon.

• Increase ECMO flow to maintain end-organ perfusion while reducing the risk of intracardiac thrombus formation.
• Administer inotropic support such as dobutamine (starting at 2-5 mcg/kg/min) or epinephrine (0.01-0.1 mcg/kg/min) to improve cardiac contractility, as suggested by previous guidelines 1.
• Consider adding vasopressors like norepinephrine (0.01-3 mcg/kg/min) if hypotension is present.
• Perform an urgent echocardiogram to evaluate cardiac function and rule out tamponade or other mechanical issues.
• Check for hypovolemia and correct with volume if indicated.
• Ensure the patient is adequately anticoagulated with heparin to maintain an activated clotting time (ACT) of 180-220 seconds, taking into account the potential risk of acquired von Willebrand syndrome during ECMO support 1. Loss of pulsatility in VAV ECMO indicates severe cardiac dysfunction, which can lead to blood stasis in the heart and subsequent thrombus formation. This is concerning because VAV ECMO provides respiratory support but relies on the patient's heart for circulation, unlike VA ECMO which provides both cardiac and respiratory support.

From the Research

Loss of Pulsatility in VAV ECMO

• The loss of pulsatility in a patient on Veno-Arterio-Venous (VAV) Extracorporeal Membrane Oxygenation (ECMO) can indicate changes in clinical status, including changes in myocardial function, inadequate preload, worsening right ventricular (RV) failure, and excessive VA-ECMO support leading to an elevated left ventricle (LV) afterload 2.
• Monitoring of the adult patient on VA ECMO includes assessing patient hemodynamics and device flow, overall gas exchange support, markers of adequate oxygen delivery, and pulsatility of the arterial blood pressure waveform 3.

Potential Causes and Interventions

• Myocardial function may be improved by titration of inotropes or vasodilators, utilization of an Impella or an intra-aortic balloon counterpulsation support devices, or by changes in VA-ECMO support 2.
• The use of colloids vs crystalloids for fluid resuscitation did not result in a significant difference in 28-day mortality in ICU patients with hypovolemia, but 90-day mortality was lower among patients receiving colloids 4.

Weaning from VA ECMO

• Adequate and durable recovery in patients supported with VA ECMO can be challenging to predict, and the optimal strategies for deciding who to wean and how to wean VA ECMO remain undefined 5.
• Most published work and expert opinions agree that once the underlying process has resolved, the minimum required physiologic parameters for weaning from ECMO include hemodynamic stability and cardiac pulsatility, adequate lung function to support oxygenation and ventilation, and evidence of recovered end organ function 5.