Extracorporeal Membrane Oxygenation (ECMO)
What is ECMO?
Extracorporeal membrane oxygenation is a type of artificial life support that can help a person whose lungs and heart aren't functioning correctly. Also called ECMO, this setup continuously pumps blood out of your body and then sends it through a series of devices that add oxygen and remove carbon dioxide. The blood is then pumped back into your body.
How does ECMO work?
ECMO is a complex setup that's only used with patients who require intensive or critical care. During the process, blood flows out of your body and through an ECMO “circuit” before being pumped back into your body. The circuit’s components include the following (additional devices may be added in some cases):
- Cannula (pronounced “can-you-la”). This is a tube that serves as a temporary entry or exit point from your body. Cannulae (pronounced “can-you-lay”) is the term used to describe more than one of these.
- Pump. The pump propels blood through the ECMO circuit. In cases where your heart is also not working properly, ECMO can support your heart and lungs at the same time.
- Oxygenator/heat exchanger. This part of the circuit adds oxygen and removes carbon dioxide from your blood. It also helps control your blood’s temperature.
- Tubing. The tubing is the channel through which your blood flows in and out of your body and from device to device in the ECMO circuit.
ECMO can follow either a central placement or a peripheral placement.
- Central. This placement uses large blood vessels located in your chest for placing the cannulae. This usually involves heart surgery to place the cannulae and keep them from moving.
- Peripheral. This placement uses large blood vessels located in your extremities. These are typically vessels in your femoral area (near your groin) or those found in your neck.
There are two main orientations used for ECMO therapy.
Venovenous ECMO goes from vein to vein and helps people who need support for their lungs only. The circuit diverts blood out of your body, starting at a cannula placed in a large vein (either central or peripheral). After passing through the ECMO circuit, the blood returns via a vein in your body (or sometimes to a specific chamber of the heart).
The re-entry point can either be a separate vein using two cannulae, or it can use a double-lumen cannula in the same vein where the blood left your body. A double-lumen cannula has two “mouths” for blood to flow through — one out of your body and the other into your body — meaning you only need one entry/exit point.
Venoarterial ECMO bypasses both your heart and lungs. The blood exits your body through a cannula placed in a vein, which diverts blood into the ECMO circuit for oxygenation and carbon dioxide removal. The blood then re-enters your body through a main artery. This bypasses your heart entirely and the ECMO circuit’s pump does the heart’s job.
Central VA ECMO requires major surgery, with your chest staying open for an extended period (sometimes days). This has increased risks — especially a risk of infection — and is only used for people who won’t survive otherwise.
Advanced peripheral VA ECMO methods
One of the biggest disadvantages of peripheral VA ECMO is it can put too much stress on your heart or cause some parts of your body to have enough oxygen while other parts don’t get enough. To avoid this, your healthcare provider may use the following advanced ECMO configurations and placements:
- Veno-venous-arterial (VVA). This configuration has blood exit your body through two cannulae in different veins, reducing the pressure placed on your heart. The blood then goes through the ECMO circuit and then back into an artery.
- Veno-arterial-venous (VAV). This configuration has blood exit your body from a vein and re-enter at two points: one in an artery and the other to a vein (or sometimes directly into a chamber of your heart). This can help distribute oxygenated blood more evenly.
What conditions can an ECMO machine treat?
Mechanical ventilation devices are a type of life support, but they can only move air and can’t add oxygen to and remove carbon dioxide directly from your blood. ECMO can exchange these gases similar to how your lungs do. ECMO can be especially valuable in making it possible for these organs to rest and heal and is getting greater use alongside CPR because it can improve your odds of survival and recovery.
ECMO is commonly used for the following conditions:
Acute respiratory distress syndrome (ARDS)
Damage to your lungs can cause acute respiratory distress syndrome, limiting how well your lungs can put oxygen in and take carbon dioxide out of your blood. This can happen with:
- Respiratory infections. These include influenza, pneumonia, the novel coronavirus that causes COVID-19, and more.
- Sepsis, which happens when your immune system overreacts to a major infection and damages your lungs (as well as other organs).
- Burns and inhalation injuries. Inhaling smoke, toxic chemicals and fumes, or breathing in superheated air from a fire can all damage your lungs.
- Drug overdose.
- Pancreatitis. Inflammation of your pancreas can cause your body to release chemicals and toxins that can damage your lungs.
- Drowning or aspirating something into the lungs, such as water, beverages, food or vomit.
Pulmonary embolism happens when a blood clot that formed somewhere in your body (usually your legs) travels to your lungs and gets stuck. This can keep blood from flowing through your lungs, which can cause deadly failure of your heart and lungs.
ECMO can be used if you have injuries to your heart from trauma, or other diseases or conditions. Some of these include:
- Heart attack. A heart attack happens when a blockage in the blood vessels of your heart stops them from getting enough oxygen. This can damage the heart muscle itself.
- Trauma. Blunt force impacts, such as from a fall or car crash, can bruise and damage the heart muscle.
Infants and newborns
Newborns and infants with heart and lung problems, especially babies born prematurely, often receive ECMO.
Transplants and surgeries
ECMO can help serve as a “bridge” until a person can get a specific type of care or procedure. One example of this is while a person waits for a heart or lung transplant. It’s also commonly used during the transplant surgery itself. ECMO is also used during surgeries on the heart and lungs and is often used during post-surgery recovery.
ECMO can also play a role in organ and tissue donation by keeping the donor alive as long as possible. This time can be used to find and prepare recipients for the transplant procedure.
How commonly is an ECMO machine used?
ECMO has become a significant asset in critical care units (CCUs) and intensive care units (ICUs) over the past 30 years. It's also getting more use as an add-on to CPR. Approximately 500 hospitals worldwide can do ECMO and a little over half of them are in the United States. ECMO was used more than 160,000 times in 2020, according to the Extracorporeal Life Support Organization. ECMO is also getting more attention recently because of its use in critically ill people with COVID-19.
Risks / Benefits
What are the advantages of being on an ECMO machine?
ECMO can be a life-saving tool for people who are critically ill because it can support the lungs and heart, which can have the following effects:
- Eases the strain on the heart and lungs, making it possible for these organs to heal.
- Keeps a person alive during a surgery or other medical procedure.
- Supports a person as they wait for a transplant.
- Helps infants who need were born with heart problems or born prematurely (which can mean their lungs aren’t fully developed).
What are the possible risks or complications of being on an ECMO machine?
While ECMO is an invaluable medical tool, it’s also one that has risks, some of them significant.
- Clotting problems. Anyone on ECMO also has to be on blood thinners because of the risk of clots forming. Your body treats a cannula like any other injury and tries to cause your blood to clot around it. Clots could also become stuck in the ECMO circuit, interrupting blood flow and potentially putting you at risk.
- Infection. Any break in your skin is a risk for an infection, and the cannulae of an ECMO circuit can give an infection direct access to your bloodstream. This can make it easier for an infection to spread throughout your body.
- Bleeding. Because the cannulae have to go into major arteries and veins, this can increase your risk for bleeding.
- Low or uneven blood oxygen levels. Under normal circumstances, your blood oxygen level should be between 95% and 100%. In general, ECMO’s target range is 86% to 92%. Maintaining an even blood oxygen level throughout your body can also be a challenge, which is why advanced cannulae placements (VVA and VAV) now exist.
- ECMO circuit failure. A mechanical failure in any part of the ECMO circuit can cause the entire circuit to stop. This can be life-threatening and needs immediate attention.
When should an ECMO machine not be used?
ECMO is less likely to help older individuals. Your healthcare provider can advise you on the age-related risks and benefits.
There are several conditions or circumstances where ECMO isn’t an option. These include:
- When the person has heart, lung or circulatory problems that aren’t repairable or that a transplant won’t fix.
- People with damage to other critical organs like their liver or brain.
- Cancer that has spread from its origin.
- Uncontrolled internal bleeding, especially in the head, or injuries that could lead to uncontrolled bleeding.
Frequently Asked Questions
How long can I stay on ECMO?
People can stay on ECMO anywhere from days to weeks. The length of time that a person will spend on ECMO depends on why they need this treatment.
What happens when you come off of ECMO?
Healthcare providers will routinely check a person’s heart and lung functions while they’re on ECMO to make sure they’re in good condition and there are no complications. This also lets healthcare providers know how much longer to keep someone on ECMO.
Once a person shows signs of recovery, healthcare providers will begin weaning them off ECMO. In most cases, this process takes between two and five days.
Can a person stay on ECMO for months, years or more?
ECMO isn’t meant for people who have no hope of recovery. It's used to support your body while recovery is underway. The only exception is to delay death for organ and tissue donation reasons.
Can ECMO be done for just the heart?
Yes, it can be used when only heart function is compromised. Alternatively, other support devices such as ventricular assist devices can be used as well.
A note from Cleveland Clinic
ECMO is an option that can help many people who are critically ill with lung and heart problems. It’s not a new treatment, having been in use for decades. Modern medicine also has a better understanding today than ever before of how ECMO can help save lives. Unfortunately, it isn’t meant for everyone. Your healthcare provider can explain the potential benefits and risks and help you decide what's best in your situation.
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