ECMO stands for Extracorporeal Membrane Oxygenation. It is a type of life support that uses a machine to pump blood rich in oxygen to support the heart or lungs, or both. The ECMO machine acts as an artificial heart and lung for a patient whose own heart or lungs cannot provide enough blood flow or get enough oxygen into the blood. ECMO is used after other methods of supporting the heart and lungs did not work. Once a patient is on ECMO, you may see an improvement because their heart and lungs may "rest" while ECMO takes over. The goal of ECMO is to let the heart and lungs recover while the patient is supported by the ECMO machine.
Picture 1: The normal heart-lung system. Blood is
Some heart defects can cause symptoms that seem at first to be a lung problem. So, before using ECMO, doctors do tests to see if the cause of the problem is the heart or the lungs. It is important to know if the heart is working well or not.
These tests are done before ECMO is started and sometimes at other times during the ECMO course:
One to three cannulas (tubes) are needed to connect the ECMO circuit to a patient. The surgeon will make a small cut, usually on the right side of the neck. A tube is usually placed through the small cut on the right side of the neck, into the jugular vein. This vein leads to the upper right chamber (right atrium) of the heart (see Picture 1). A second tube is sometimes placed through the same small cut into the carotid artery, another vessel in the neck. These tubes are then connected to the ECMO machine. After the procedure, the blood vessels that are used for this may be permanently tied off and cannot be used in the future. There are 3 other arteries and 3 other veins in the neck that usually continue to supply the brain with blood and oxygen.
Sometimes other sites may be used. For some patients the tubes are placed directly into the heart (right atrium) and into the large artery coming from the heart (aorta). These tubes are then connected to the ECMO machine. These blood vessels are not tied off, and are repaired after the ECMO course.
Picture 2: How blood pumps through the ECMO machine
There are different kinds of support that ECMO can provide. Some patients are placed on ECMO to only support their lungs, known as veno-venous ECMO (VV ECMO). This type of ECMO does not support the heart, but is intended to let the lungs rest. If a child is placed on ECMO to support only the lungs, the blood is taken out of the right side of the heart (right atrium), oxygen is added and the blood is then returned to the right atrium where the heart then pumps this blood to the lungs and body.
Other patients are placed on ECMO to support their heart and lungs, known as veno-arterial ECMO (VA ECMO). If a child is placed on ECMO to support the heart, the blood is taken out of a vein and returned to an artery.
The ECMO machine drains blood from the tube in the jugular vein to the ECMO machine (see Picture 2). The ECMO machine can then pump the blood. The blood is pumped through an artificial lung called an oxygenator. This puts oxygen into the blood and takes carbon dioxide (waste gas) out of the blood. The blood is warmed to body temperature as it flows through the heat exchanger within the oxygenator (Picture 2). Blood that is rich with oxygen is then returned through the tube in either the carotid artery or jugular vein.
The blood coming from the child will be dark red (with little oxygen). The blood going back will usually be a brighter red (with oxygen).
During ECMO, we will be giving blood products through the ECMO circuit. Blood is given to replace the blood taken for laboratory tests. Platelets (the part of the blood that helps with clotting) are given often to help prevent bleeding. Please see Helping Hand HH-II-122, Blood Transfusion.
ECMO patients usually receive intravenous (IV) fluids for nutrition. Feedings through a tube (placed in the mouth or nose which goes to the stomach) may be started while on ECMO. Some patients will be allowed to eat regular food while on ECMO. After ECMO, regular feedings will be started as soon as possible. As the patient gets stronger, he or she can start taking a bottle, breast-feeding or eating a regular diet as tolerated and ordered by the physician.
The time each patient is on ECMO varies. The amount of time depends on each child’s ability to recover from the underlying illness that required the use of ECMO.
There are several ways to know if there is improvement:
If the child has not improved after 3 to 4 weeks of ECMO, it may mean the heart or lung disease cannot be reversed. Sometimes, a lung biopsy (taking a tiny piece of lung tissue to look at under a microscope) or a cardiac catheterization is needed. These tests can give more information about the heart or lung disease. Please see Helping Hand HH-III-3, Cardiac Catheterization. If the medical team agrees that ECMO can no longer be expected to bring about a cure, the patient may be taken off ECMO. Other medical therapy will then be started. The doctors will always discuss these options with you before decisions are made.
To wean means to slowly readjust back to normal.
Be sure to keep all your appointments with the follow up physicians.
If you have any questions, be sure to ask your doctor or nurse,
HH-II-90 11/90, Revised 10/14 Copyright 1990, Nationwide Children's Hospital