Extracorporeal Membrane Oxygenation

Rationale for ECMO

Support Failing Heart

Veno-Arterial ECMO

Can provide full support of the heart and lungs, similar to cardiopulmonary bypass

Support Failing Lungs

Veno-Venous ECMO

Gas exchange of up to 80% of cardiac output with no cardiovascular support

Extracorporeal CO2 removal (ECCO2R)

Oxygenation is provided by slow ventilation of the native lungs while CO2 removal is accomplished by the ECMO circuit

Artero-Venous ECMO (NovaLung)

Gas exchange driven by systemic arterial flow through an extracorporeal membrane

ECMO vs. Cardiopulmonary Bypass (CPB)


CPB cannulae are typically placed in the ascending aorta and vena cavae, allowing complete bypass. The venous inflow cannula in ECMO can be placed in the femoral or internal jugular veins, limiting its size and the amount of support. Arterial cannula (if utilized) is placed femorally. CPB (intraoperative) can also be converted to ECMO, in which case right atrial and ascending aortic cannulae will be utilized

Bells & Whistles

ECMO circuits do not have a venous reservoir. Temperature control not always possible. Depending on the circuit, hemofiltration may or may not be possible

Types of ECMO


Near complete cardiopulmonary support can be provided. Arterial cannula (femoral) + either internal jugular or femoral vein. Note that because ~ 20% of blood passes through the lungs and incomplete mixing, the oxygen content in the aortic arch may be significantly lower than in the descending aorta. Consider advanced monitoring (e.g. NIRS + bilateral pulse oximeters). Risk of thrombotic complications is substantial and a major source of morbidity


Two separate venous cannulas or one dual-lumen internal jugular vein cannula. 100% of blood passes through the heart, only 80% of it is oxygenated by the membrane (thus some mechanical ventilation may be indicated)


Cannulation strategy identical to V-V ECMO. Depends on mechanical ventilation for oxygenation (but not CO2 removal)

A-V ECMO (NovaLung)

Utilizes arterial pressure to force blood through a membrane gas exchanger. Simplest form of ECMO available. Provides no cardiovascular support. May increase left ventricular afterload. Cannot provide complete respiratory support

Indications and Contraindications to ECMO

Indications and Contraindications to ECMO


  • Primary Reversible Respiratory Failure
  • Reversible Cardiogenic Shock


  • Multiorgan Failure
  • Inability to anticoagulate

Evidence for Adult ECMO for Respiratory Failure

Zapol WM et al. JAMA 242: 2193, 1979

Prospective randomized, multicenter (9) study. 90 adult patients with hypoxemia were randomized to conventional mechanical ventilation (48) or mechanical ventilation and partial venoarterial bypass (42). Mortality rate 92% (control) vs. 90% (intervention)
Major setback for ECMO community. Problem – ìlung restî not employed (TV were normal, FiO2 was lowered). Low lung perfusion (Qp:Qs 0.1)

Morris AH et al. Am J Respir Crit Care Med 149: 295, 1994

ìLung restî theory ñ avoid iatrogenic injury (2-4 breaths/min). Randomized, single center study. 40 patients with severe ARDS were randomized to conventional postive pressure ventilation or pressure-controlled inverse ratio ventilation plus extracorporeal CO2 removal. Mortality was 58% (control) and 67% (intervention, p = 0.8) respectively

Peek GJ et al. Lancet 374: 1351, 2009

Randomized, multicenter trial. 180 received “conventional management” or referral for consideration of ECMO. Primary analysis was by intention to treat. 180 were enrolled and randomly allocated. 68 of 90 (75%) patients actually received ECMO; 63% (57/90) of patients allocated to consideration for treatment by ECMO survived to 6 months without disability compared with 47% (41/87) of those allocated to conventional management (relative risk 0.69, p=0.03). Criticisms: delivery of ìconventionalî care makes for unfair comparison [Peek GJ et al. Lancet 374: 1351, 2009]

Cost of ECMO

An analysis of 14 patients undergoing ECMO in Europe determined that the mean estimated cost for the ECMO procedure was $73,122. Mean estimated total hospital costs was $213,246. 82% of costs were related to personnel use. Mean ECMO duration was 9.5 days and average length of hospital stay was 51.5 days. Complications included bleeding (10 patients), renal failure (six patients), pneumonia (four patients) and stroke (one patient) [Mishra V et al. Eur J Cardiothorac Surg 37: 339, 2010]