Extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a form of extracorporeal life support, operated by a perfusionist, providing prolonged cardiac and respiratory support to people whose heart and lungs are unable to provide an adequate amount of oxygen, gas exchange or blood supply (perfusion) to sustain life. The technology for ECMO is largely derived from cardiopulmonary bypass, which provides shorter-term support with arrested native circulation. The device used is a membrane oxygenator, also known as an artificial lung.

ECMO works by temporarily drawing blood from the body to allow artificial oxygenation of the red blood cells and removal of carbon dioxide. Generally, it is used either post-cardiopulmonary bypass or in late-stage treatment of a person with profound heart and/or lung failure, although it is now seeing use as a treatment for cardiac arrest in certain centers, allowing treatment of the underlying cause of arrest while circulation and oxygenation are supported. ECMO is also used to support patients with the acute viral pneumonia associated with COVID-19 in cases where artificial ventilation alone is not sufficient to sustain blood oxygenation levels.

Medical uses

Guidelines that describe the indications and practice of ECMO are published by the Extracorporeal Life Support Organization (ELSO). Criteria for the initiation of ECMO vary by institution, but generally include acute severe cardiac or pulmonary failure that is potentially reversible and unresponsive to conventional management. Examples of clinical situations that may prompt the initiation of ECMO include the following:

Hypoxemic respiratory failure with a ratio of arterial oxygen tension to fraction of inspired oxygen (PaO2/FiO2) of <100 mmHg despite optimization of the ventilator settings, including the fraction of inspired oxygen (FiO2), positive end-expiratory pressure (PEEP), and inspiratory to expiratory (I:E) ratio

Hypercapnic respiratory failure with an arterial pH <7.20

Refractory cardiogenic shock

Thyroid storm

Cardiac arrest

Failure to wean from cardiopulmonary bypass after cardiac surgery

As a bridge to either heart transplantation or placement of a ventricular assist device

As a bridge to lung transplantation

Septic shock is a more controversial but increasingly studied use of ECMO

Hypothermia, with a core temperature between 28 and 24 °C and cardiac instability, or with a core temperature below 24 °C.

In those with cardiac arrest or cardiogenic shock, it is believed to improve survival and good outcomes. However, a recent clinical trial has shown that in patients with cardiogenic shock following acute myocardial infarction, ECLS did not improve survival (as measured via 30-day mortality); on the contrary, it resulted in increased complications (e.g., major bleeding, lower limb ischemia).