ECMO (Extracorporeal Membrane Oxygenation): How It Works, Types, Risks, and Recovery
Updated: 6 days ago
Written and medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026 · How we review
Quick Answer: What is ECMO?
ECMO (extracorporeal membrane oxygenation) is a temporary life-support machine that pumps blood out of the body, adds oxygen, removes carbon dioxide, and returns it, so severely failing lungs, and sometimes the heart, can rest and heal. It is used for conditions like ARDS, pulmonary embolism, and serious heart injury when other treatments have failed. [1]
What the research says
ECMO lowered 90-day deaths in severe ARDS. In a pooled analysis of 429 patients from two randomized trials, 36% of patients treated with ECMO had died by day 90, compared with 48% of patients given conventional care (relative risk 0.75). (Combes et al., Intensive Care Medicine, 2020) [2]
Complications are common when ECMO supports the heart. Across 20 studies of 1,866 adults with cardiogenic shock or cardiac arrest, pooled rates were 55.6% for acute kidney injury, 40.8% for major bleeding, 30.4% for significant infection, 16.9% for reduced blood flow to the leg, and 5.9% for stroke. (Cheng et al., The Annals of Thoracic Surgery, 2014) [3]
Most people who survive the first month are alive five years later. In 370 ECMO patients, 5-year survival was 33% after VA-ECMO and 36% after VV-ECMO; among those alive at 30 days, it rose to 73% and 71%. (Rossong et al., The Journal of Thoracic and Cardiovascular Surgery, 2023) [4]
Key takeaways
ECMO is temporary life support that does the work of the lungs, and sometimes the heart, outside the body. [1]
There are two main types: VA-ECMO supports the heart and lungs; VV-ECMO supports the lungs only. [1]
It is used for severe lung or heart failure when other treatments have failed, but recovery is still possible. [1]
People can stay on ECMO for hours, days, or weeks; weaning off usually takes two to five days. [1]
Main risks include clotting, bleeding, infection, stroke, and circuit failure. [1]
Long-term survival depends heavily on the reason a person needed ECMO. [1][4]
What is ECMO?
ECMO is a type of artificial life support that helps when the lungs and heart are not working as they should. [1]
"Extracorporeal" means "outside the body." The machine continuously pumps blood out of the body, sends it through a device that adds oxygen and removes carbon dioxide, and then pumps it back in. [1]
This takes the strain off the heart and lungs. With less work to do, these organs get a chance to heal while the medical team treats the underlying illness. [1]
ECMO has been in use for decades, and centers worldwide have reported more than 290,000 ECMO patients to the ELSO Registry. Besides critically ill adults, it can also help newborns with heart problems or lungs that are not fully developed. [1]
What are the types of ECMO?
The two main types of ECMO are VA-ECMO (veno-arterial), which supports both the heart and the lungs, and VV-ECMO (veno-venous), which supports the lungs only. [1]
Feature | VA-ECMO (veno-arterial) | VV-ECMO (veno-venous) |
What it supports | Heart and lungs | Lungs only |
How it works | Bypasses both the heart and the lungs | Oxygenates blood; the heart still pumps on its own |
Effect on the heart | Takes over the heart's pumping work | The heart may work better because it receives more oxygen |
Typical use | Heart damage, such as after a heart attack or during heart surgery | Severe lung failure, such as ARDS |
Source: [1]
Who needs ECMO?
ECMO is used for people with severe heart or lung problems when other treatments have failed but there is still a chance of recovery. [1]
Condition | Why ECMO may help |
Acute respiratory distress syndrome (ARDS) | A life-threatening lung injury caused by sepsis, COVID-19, major trauma, burns, or drug overdose; ECMO takes over gas exchange while the lungs recover |
A blood clot, usually from the legs, blocks blood flow in the lungs; ECMO keeps oxygen moving while the clot is treated | |
Heart muscle damage from a heart attack, trauma, or other causes can leave the heart too weak to pump | |
Transplants and surgery | ECMO can support a person waiting for a heart or lung transplant, or during and after heart or lung surgery |
Newborns | Babies born with heart problems or underdeveloped lungs |
Source: [1]
How does ECMO work, step by step?
ECMO works by moving blood out through a tube in a large blood vessel, oxygenating it in a machine, and returning it to the body. [1]
Cannulation. Doctors place tubes (cannulas) into a large blood vessel in the chest, leg, or neck. This is called ECMO cannulation. The patient is sedated and does not feel the tubes going in. [1]
Pumping. A pump pulls blood out through the tubing. [1]
Gas exchange. The blood passes through a device that adds oxygen and removes carbon dioxide, the same job healthy lungs do. [1]
Return. The machine pumps the oxygen-rich blood back into the body. [1]
Monitoring. An ECMO specialist checks heart and lung function regularly to catch complications and judge how much longer support is needed. [1]
Weaning. Once the patient shows signs of recovery, the team slowly reduces support. This usually takes two to five days. [1]
Decannulation. The tubes are removed and the skin is stitched closed. [1]
While on ECMO, a person may be awake or sedated. [1]
How long do people stay on ECMO?
People can stay on ECMO for anywhere from a few hours to several weeks, depending on why they need it. [1]
The machine gives the lungs, and sometimes the heart, time to rest. Meanwhile, the care team treats the condition that caused the organ failure. [1]
What are the risks of ECMO?
The main risks of ECMO are blood clots, bleeding, infection, low or uneven blood oxygen, circuit failure, and stroke. [1]
Risk | What happens |
Blood clots | Clots can form and get stuck in the circuit, so everyone on ECMO needs blood thinners |
Bleeding | Tubes enter major blood vessels, and blood thinners further raise bleeding risk |
Infection | Any break in the skin allows germs in; tube-related infections can spread through the bloodstream |
Low or uneven oxygen | The target oxygen range is slightly lower than normal, and keeping an even level across the body can be hard |
Circuit failure | A mechanical failure anywhere in the circuit can stop the whole system and is life-threatening |
Stroke | Bleeding in the brain, or clots traveling from the circuit to the brain, can cause a life-threatening stroke |
Source: [1]
In research on heart-related ECMO, kidney injury affected about 6 in 10 patients and major bleeding about 4 in 10, while stroke affected about 6 out of 100. [3] For warning signs of stroke, see our stroke guide.
Are there long-term effects of ECMO?
ECMO can cause long-term kidney and leg problems in some people. [1]
Kidneys: If the kidneys do not get enough blood flow during ECMO, they can fail. Dialysis can take over in the short term, but some people need it for life. Learn more about acute kidney injury. [1]
Legs: Poor blood flow to the leg where the machine connects can damage leg tissue. In rare cases, surgery is needed to repair the damage or remove part of the leg. [1]
Some survivors also report ongoing trouble with daily activities and high post-traumatic stress scores years later, which is why long-term follow-up matters. [4]
What is the survival rate after ECMO?
Survival after ECMO varies widely depending on why a person needed it. [1]
Group | 5-year survival |
All adults treated with ECMO | About 3 out of 10 |
Adults who survived the first 30 days | About 7 out of 10 |
Source: [1][4]
A person can die while on ECMO if the underlying condition cannot be fixed. ECMO supports the body; it does not cure the illness itself. [1]
What is the difference between ECMO and a ventilator?
ECMO exchanges oxygen and carbon dioxide directly in the blood, while a ventilator can only move air in and out of the lungs. [1]
ECMO | Ventilator | |
What it does | Adds oxygen to and removes carbon dioxide from the blood outside the body | Pushes air into and out of the lungs |
Needs working lungs? | No, it bypasses the lungs | Yes, the lungs must still exchange gas |
Can support the heart? | Yes (VA-ECMO) | No |
Source: [1]
When is ECMO not used?
ECMO is not an option when the heart, lungs, or circulation cannot be repaired or fixed by a transplant. [1] It is also not used when a person has:
Damage to other critical organs, such as the liver or brain
Cancer that has spread from where it started
Uncontrolled internal bleeding, especially in the head, or injuries likely to cause it
Blood vessels that cannot be safely accessed
Source: [1]
How can families help a loved one on ECMO?
Families can help a loved one on ECMO by offering simple comforts, after checking with the care team first. [1]
Talk or read to them.
Sing or play music.
Bring family photos for them to see.
Put lotion on their skin.
Source: [1]
Conclusion
ECMO is one of the most advanced forms of life support in modern medicine. It buys time by doing the work of the lungs, and sometimes the heart, while doctors treat the cause of the failure. [1]
It carries real risks, and survival depends on the underlying illness. Still, research shows it can lower deaths in severe ARDS, and most people who make it through the first month are alive years later. [2][4]
If you or a loved one is facing ECMO, ask the care team about the expected benefits, the specific risks, and the plan for weaning.
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FAQ
What does ECMO stand for?
ECMO stands for extracorporeal membrane oxygenation. "Extracorporeal" means outside the body, because the blood is oxygenated in a machine before returning to the body. [1]
Is a person awake on ECMO?
A person may be awake or sedated while on ECMO. They are always sedated while the tubes are placed, so they do not feel them going in. [1]
How long can someone stay on ECMO?
Someone can stay on ECMO for hours, days, or weeks, depending on why they need it. Weaning off the machine usually takes two to five days. [1]
What conditions are treated with ECMO?
ECMO is used for ARDS, pulmonary embolism, heart muscle damage from a heart attack or trauma, and support before or after heart or lung transplants and surgery. It can also help newborns with heart or lung problems. [1]
What is the difference between VA-ECMO and VV-ECMO?
VA-ECMO supports both the heart and the lungs, while VV-ECMO supports only the lungs. With VV-ECMO, the heart may still work better because it receives more oxygen. [1]
What are the most serious risks of ECMO?
The most serious risks of ECMO are bleeding, blood clots, infection, stroke, and failure of the machine's circuit. Everyone on ECMO needs blood thinners to prevent clots, which raises bleeding risk. [1]
What is the survival rate after ECMO?
About 3 in 10 adults treated with ECMO are alive five years later. Among those who survive the first 30 days, about 7 in 10 are alive at five years. [1][4]
Is ECMO better than a ventilator?
ECMO and a ventilator do different jobs. A ventilator only moves air, while ECMO adds oxygen and removes carbon dioxide directly from the blood, so it can work even when the lungs cannot. [1]
Can a person on ECMO eat?
Most people on ECMO get nutrition through a feeding tube or through a vein. The care team adjusts feeding based on how the person is doing.
How is someone taken off ECMO?
As the lungs or heart recover, the team slowly lowers ECMO support and watches how the body copes. When the organs can work on their own, the tubes are removed.
Related Reading
Cardiopulmonary Bypass: How the Heart-Lung Machine Works explains how the heart-lung machine supports heart surgery.
References
Cleveland Clinic. Extracorporeal Membrane Oxygenation (ECMO). Cleveland Clinic. Last updated May 18, 2026. https://my.clevelandclinic.org/health/treatments/21722-extracorporeal-membrane-oxygenation-ecmo
Combes A, Peek GJ, Hajage D, et al. ECMO for severe ARDS: systematic review and individual patient data meta-analysis. Intensive Care Med. 2020;46(11):2048-2057. PMID: 33021684. https://doi.org/10.1007/s00134-020-06248-3
Cheng R, Hachamovitch R, Kittleson M, et al. Complications of extracorporeal membrane oxygenation for treatment of cardiogenic shock and cardiac arrest: a meta-analysis of 1,866 adult patients. Ann Thorac Surg. 2014;97(2):610-616. PMID: 24210621. https://doi.org/10.1016/j.athoracsur.2013.09.008
Rossong H, Debreuil S, Yan W, et al. Long-term survival and quality of life after extracorporeal membrane oxygenation. J Thorac Cardiovasc Surg. 2023;166(2):555-566.e2. PMID: 35346489. https://doi.org/10.1016/j.jtcvs.2021.10.077
Extracorporeal Life Support Organization. ELSO International Summary of Statistics. ELSO Registry. Accessed October 31, 2026. https://www.elso.org/registry/internationalsummaryandreports.aspx
Medical disclaimer
This article is for general educational purposes only and does not replace professional medical advice, diagnosis, or treatment. Decisions about ECMO are made by specialized critical care teams based on each patient's condition. Always speak with a qualified healthcare provider about your or your loved one's care. If you think someone is having a medical emergency, call your local emergency number right away.
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