Extracorporeal membrane oxygenation or ECMO is a way of supporting the heart and lungs for people who are seriously ill. Its most common application is in pediatric settings, but it can also be used for adults. ECMO was adapted from heart-lung bypass machines by Dr. Robert Bartlett of the University of Michigan Hospital in the 1970s, and unlike bypass it can be used for longer periods of time, though lengthier use is associated with higher degree of complications.
The “extracorporeal” in extracorporeal membrane oxygenation means that blood is circulated outside of the body into the ECMO machine. The machine feeds the blood through what is called an oxygenation membrane, which may also be termed an artificial lung, that adds oxygen back to the blood. The ECMO machine also must keep the blood at the appropriate temperature, so as not to cool down the body when it flows back into it. In all cases, “blue blood” or blood running out of oxygen gets oxygenated and returns as “red blood” or oxygen rich blood.
Two types of extracorporeal membrane oxygenation exist, and these are called veno-arterial, and veno-venous (VA and VV). VA ECMO removes blood from a vein and returns it to an artery, bypassing the heart. This provides support for heart and lungs. VV ECMO removes blood from a vein and returns it to a vein, and this tends to be used most when only the lungs are compromised. In both types people can expect to see two catheters or cannulas attached to the body, one removing blood, and one returning it.
Use of extracorporeal membrane oxygenation can be encouraged under many circumstances. Some of the reasons it could be applied include severe compromise of the lungs, waiting for heart/lung transplant, heart transplant or heart surgery, immaturity of the lungs, meconium aspiration syndrome and pneumothorax. Amount of days a person might spend on ECMO varies and may also depend on people tolerating the therapy.
Risks of ECMO include profuse bleeding or formation of blood clots. Heparin, an anti-coagulant, must be used to make sure blood doesn’t clot in the machine. This use, especially in very young children, translates to an elevated risk of bleeding in the brain. This is why, although ECMO is considered effective therapy, it is also considered a therapy of last resort.
Highly trained perfusionists closely supervise people on ECMO machines. Not every hospital has these machines available because they can only be used when a perfusionist exists to operate them and make certain the patient is tolerating the treatment. ECMO treatment is most common in tertiary level facilities.
While extracorporeal membrane oxygenation can be viewed as a good thing that may increase survival rate with some conditions, it is not always greeted with enthusiasm, especially by parents whose newborns undergo it. ECMO treatment is difficult on parents, who may not be able to hold or feed their babies for many days. They can, however, touch, stroke and talk to their newborns or young children, and this is highly encouraged.
