Extra-Corporeal Membrane Oxygenation

Original Editor - Saud Alghamdi Top Contributors - Saud Alghamdi, Kim Jackson, Vidya Acharya and Ewa Jaraczewska

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Introduction

In 2022, it is estimated that nearly 200,000 patients received Extra-Corporeal Membrane Oxygenation (ECMO). ECMO is a technique that oxygenates the blood outside the body. It’s typically used when conventional ventilation is unable to oxygenate the blood adequately.

It is important to understand that ECMO is a supportive therapy, not a disease-modifying treatment. Similar to a ventilator or a dialysis machine, ECMO doesn't cure the underlying disease but takes over a vital function (oxygenation or blood circulation) when the body's organs are unable to do so adequately.

ECMO is a highly specialised technique that requires the input of intensive care specialists, cardiothoracic surgeons as well as ECMO-trained nurses and perfusion scientists.

How does ECMO work

ECMO is a technique that oxygenates the blood outside the body. It’s typically used when conventional ventilation is unable to oxygenate the blood adequately.

In ECMO, the blood is drained from the vascular system, circulated outside the body by a mechanical pump and then reinfused into the circulation. While the blood is outside the body, hemoglobins become fully saturated with oxygen and carbon dioxide (CO2) is removed from them.

Types of ECMO

There are two types of ECMO. Veno-arterial (VA) ECMO can be used for heart and lung support, while veno-venous (VV) ECMO is used for lung support only.

VA-ECMO

VA-ECMO drains the blood from the venous system, reinfuses it into the arterial system and provides complete cardiopulmonary support.

VV-ECMO

VV-ECMO drains the blood from the venous system, reinfuses it into the venous system and provides gas exchange. Unlike VA-ECMO, VV-ECMO does not provide direct cardiac support.

Is Physiotherapy safe for patients on ECMO?

A 2019 systematic review found that physiotherapy interventions including early ambulation for patients on ECMO is considered safe due to the absence of severe adverse events and the small number of mild adverse events. Of the 259 patients who underwent physiotherapy interventions, only 4 patients presented with adverse events. One study reported two complications from femoro-femoral cannulation with one patient presenting with severe leg swelling and another with an obstructive thrombus in the return cannula. One study reported a cannula fracture during physiotherapy mobilisation and one study reported a decrease in peripheral oxygen saturation that was sufficiently compensated for by increased blood flow during ECMO.