Extracorporeal Membrane Oxygenation (ECMO) Procedure

Overview

Extracorporeal Membrane Oxygenation (ECMO) is a form of advanced life support used when a person’s heart and lungs are too weak or damaged to function on their own. Doctors use ECMO for patients with serious heart or lung conditions, such as those caused by illness, injury, or complications from other treatments.

It is often used when other medical options are no longer effective. People may wonder how this life support system works or when it is needed. Understanding ECMO can help patients and families feel more prepared if they ever face a situation where this technology is considered.

What Is Extracorporeal Membrane Oxygenation (ECMO)?

Extracorporeal Membrane Oxygenation, or ECMO, is a form of advanced life support. Doctors use it for patients who have serious heart or lung problems when normal treatments are not enough. ECMO supports the body by:

• Pumping blood outside of the body through a machine.
• Adding oxygen to the blood and removing carbon dioxide using a membrane oxygenator (sometimes called an artificial lung).
• Returning the treated blood to the patient.

Another name for ECMO is Extracorporeal Life Support (ECLS). It lets the heart and lungs rest and heal by taking over their work for a while. There are two main types of ECMO:

• Veno-Venous (VV) ECMO: supports the lungs.
• Veno-Arterial (VA) ECMO: supports both the heart and lungs.

The Extracorporeal Life Support Organization (ELSO) is an international group that tracks ECMO use and safety.

Main Parts of An ECMO System

Component	Description
Pump	Moves blood through the circuit
Membrane Oxygenator	Adds oxygen, removes carbon dioxide
Cannulas	Tubes placed in blood vessels

ECMO is sometimes called an artificial lung because it copies how the lungs add oxygen to blood.

How ECMO Works

ECMO gives mechanical support for people with severe lung or heart problems. It moves blood outside the body for gas exchange, replacing the main job of the lungs and, in some cases, the heart.

Principles of Gas Exchange

ECMO keeps oxygen and carbon dioxide levels in the blood safe when the lungs or heart can’t. Large IV tubes called cannulas draw blood into the ECMO circuit. Inside the circuit, a membrane oxygenator acts like an artificial lung—adding oxygen and removing carbon dioxide.

This supports other organs and keeps tissues alive. The machine monitors gas levels in real time, and doctors check blood gases regularly to make sure everything stays in range.

Circuit Components

The ECMO circuit includes:

• Cannulas: Large tubes placed in blood vessels to guide blood in and out
• Pump: Moves blood through the system (roller or centrifugal)
• Membrane Oxygenator: Adds oxygen and removes carbon dioxide through gas-permeable fibers
• Heater: Maintains body temperature
• Monitors: Track blood flow and gas levels

All parts work together to manage blood flow, oxygen delivery, and carbon dioxide removal.

Types of ECMO Systems

Veno-Arterial (V-A) ECMO

Veno-arterial ECMO supports both the heart and the lungs. With V-A ECMO, a cannula takes blood out from a large vein, and another cannula delivers the oxygenated blood back into a large artery. This setup gives full mechanical support.

Oxygen-rich blood is pumped directly into the arteries to supply organs even when the heart isn’t working well. Doctors usually use V-A ECMO for people with heart failure or after cardiac arrest. The circuit also helps control blood pressure by controlling how much blood returns to the arteries.

Veno-Venous (V-V) ECMO

Veno-venous ECMO supports the lungs only. Both cannulas are placed in veins—one draws blood out, and the other returns oxygenated blood back to the body’s veins. The heart is still responsible for moving blood around the body.

Doctors use V-V ECMO mainly for severe lung failure, like pneumonia or ARDS, when mechanical ventilation and an endotracheal tube cannot keep oxygen levels safe. This method allows the lungs to rest while blood gases stay balanced. It does not give support if the heart is failing, so it is not used for cardiac problems.

Choosing the Right ECMO Type

Doctors choose the ECMO system based on what organ systems need support.

• If only the lungs are failing, VV ECMO is used.
• If both the heart and lungs need assistance, VA ECMO is the appropriate choice.

Type	Supports	Blood Returned To	Common Uses
VV ECMO	Lungs only	Vein	Severe lung failure
VA ECMO	Heart & lungs	Artery	Heart and lung failure

Indications and Patient Selection

Doctors use ECMO in critical care for people with life-threatening heart or lung failure. These patients often do not respond to standard treatments. Main indications for ECMO include:

• Severe respiratory failure, such as acute respiratory distress syndrome (ARDS)
• Cardiac failure, including cases not responding to typical treatments
• Heart failure after cardiac surgery
• Lung failure due to infection or trauma

Doctors also consider ECMO for high-risk patients like infants, newborns, and people with serious lung or heart conditions. Typical patient selection criteria:

• Severe, but possibly reversible, respiratory or cardiac failure.
• Failure to improve with conventional therapies (like ventilation or medication).
• No significant brain damage or other conditions that make recovery unlikely.

Here is a simple table to summarize:

Indication	Typical Patient
Severe respiratory failure (ARDS)	Adults, newborns
Cardiac failure	Critically ill patients
Failure after surgery	Infants, adults
Severe lung infection	High-risk patients

Contraindications to ECMO

• Advanced, irreversible disease
• Severe brain injury
• Terminal cancer
• Conditions where recovery is not expected

Each case should be reviewed individually by critical care teams. Close monitoring and clear discussion of potential benefits and risks are essential.

Common Conditions Treated With ECMO

Acute Respiratory Distress Syndrome (ARDS)

ARDS causes the lungs to fill with fluid, making it very hard to breathe. This condition can result from pneumonia, sepsis, trauma, burns, or inhaling smoke or chemicals. People with ARDS often need a ventilator, but sometimes even that is not enough.

In these cases, doctors use ECMO to take over the work of the lungs. It removes carbon dioxide and adds oxygen to the blood outside the body. By allowing the lungs to rest, ECMO gives them time to heal. Doctors sometimes use it in connection with severe aspiration, drowning, or injuries from accidents.

Cardiac Arrest and Cardiogenic Shock

During cardiac arrest, the heart stops pumping blood. Cardiogenic shock means the heart is too weak to supply blood to the body. Both are life-threatening emergencies. Doctors can use ECMO in these situations. It takes over the work of the heart and lungs for a short period.

This can give doctors time to treat the cause, such as a heart attack, myocarditis, or pulmonary embolism. For some, doctors use ECMO as a bridge to a heart transplant or further surgery. In cases where the heart cannot recover right away, ECMO can keep vital organs alive.

COVID-19 and Influenza

Severe cases of COVID-19 or influenza can lead to serious lung failure or ARDS. Some patients cannot get enough oxygen, even with a ventilator. In these cases, doctors may consider ECMO. By doing the job of the lungs, ECMO can help patients who have severe viral pneumonia or lung damage.

It has become a known option during the COVID-19 pandemic and flu seasons with critical cases. ECMO supports the body while the lungs recover from the infection. It is not a cure, but it buys important healing time.

Neonatal and Pediatric Uses

Doctors use ECMO in newborns and children with certain heart or lung conditions. Common reasons include meconium aspiration syndrome, congenital diaphragmatic hernia, and respiratory failure. Babies with pneumonia or sepsis may also need ECMO.

In some cases, doctors use ECMO to support children awaiting lung or heart transplants. It provides oxygen and blood flow when their organs cannot. Doctors use ECMO carefully in this group because of the risks involved. Still, it can be life-saving for critically ill infants and children when other options are not working.

The ECMO Procedure

Preparation and Cannulation

Preparation begins with the team evaluating the patient’s needs and ensuring all equipment is ready. The team usually cares for the patient in an intensive care unit (ICU) or cardiac care unit (CCU).

A team of specialists—including doctors, nurses, and often a perfusionist—places an intravenous line and gives medications for pain and sedation to prepare the patient. The cannulation process involves the team inserting flexible tubes called cannulas into large blood vessels, often in the neck, chest, or groin.

The team uses ultrasound or imaging tools like x-rays and sometimes an echocardiogram to guide and confirm correct placement of the cannulas. The cannulas allow blood to move from the body to the ECMO machine and back. After the team completes cannulation, they start the ECMO circuit and check for proper blood flow and oxygen levels before moving to ongoing care.

Monitoring and Supportive Care

A dedicated team in the ICU constantly monitors patients on ECMO. The team includes doctors, nurses, and perfusionists who track vital signs, oxygen levels, and blood pressure.

The ECMO machine takes over oxygenation and removal of carbon dioxide from the blood. The team may continue mechanical ventilation but often at lower settings to give the lungs a chance to rest. They check the cannula sites often to prevent infection or bleeding.

Daily imaging tests like chest x-rays, ultrasound, and lab work help guide care. The team closely tracks changes in heart or lung function, sometimes using an echocardiogram. They adjust medicines and fluids as needed, and provide nutrition through feeding tubes or IV lines if required.

Weaning From ECMO

Weaning is the gradual process in which the care team reduces ECMO support as the patient’s lungs or heart begin to recover. Intensivists and cardiologists perform regular tests to check if the organs can function on their own. The team may slowly lower the amount of support from the ECMO machine.

During this time, doctors closely watch vital signs, oxygen levels, and blood gases. If the patient remains stable with less support, the team briefly stops the machine to observe how the body manages. When it is safe, they remove the cannulas and support the patient with regular care, including ventilation or oxygen if needed.

Risks and Complications

Patients on ECMO face several possible risks and complications. The procedure involves moving blood outside the body, which can lead to problems. Doctors and nurses closely watch for these issues. Bleeding is a common risk because the team gives patients blood thinners like heparin to prevent clots.

This can make bleeding harder to control, especially after surgery or injury. In some cases, patients may develop coagulopathy, which means their blood does not clot as it should. Blood clots can still form in the ECMO machine or in the body even with blood thinners. These clots may block blood flow, cause a stroke, or lead to limb ischemia (blocked blood to an arm or leg).

Heparin-induced thrombocytopenia is a rare problem where the body reacts to heparin, causing a drop in platelets and increasing the risk for blood clots. Infection is another serious risk. The tubes entering the body can let bacteria in, which might lead to sepsis. Nurses and doctors watch for signs of infection at all times. Possible complications also include:

• Edema (swelling)
• Electrolyte imbalances
• Kidney function problems
• Anaphylaxis (serious allergic reaction)
• Seizures

Teams use constant monitoring to catch problems early and adjust care as needed.

Patient Outcomes and Recovery

Survival rates for people treated with ECMO depend on their medical condition and how critical they are when treatment starts. ECMO is used for patients who are very sick and need extra support for their heart or lungs.

Recovery after ECMO can be a long process. Some patients may go home soon after treatment, but others need weeks or months of rehabilitation. Many patients experience weakness and need physical therapy.

Common Areas Impacting Recovery

• Muscle strength
• Lung function
• Heart function
• Mental health
• Daily activities

A table summarizing possible outcomes:

Outcome	Description
Survival to discharge	Patient leaves hospital alive
Long-term survival	Living 6 months to 10 years later
Full recovery	Returns to normal activity level
Partial recovery	Needs some assistance or therapy
Poor recovery	Limited function or ongoing issues

Quality of life after ECMO varies. Some patients return to their regular lives, while others have lasting problems, such as trouble breathing or moving. Mental health support is important, as anxiety and depression are not uncommon. Family involvement and support from care teams can help with emotional health and recovery.

Support Therapies and Adjunctive Care

Patients on Extracorporeal Membrane Oxygenation (ECMO) often need extra care to support their organs and recovery. Support therapies and adjunctive care focus on keeping the body stable and preventing further problems. Clinicians usually continue mechanical ventilation during ECMO.

They adjust ventilator settings to lower the risk of lung injury, often using gentle or “lung-protective” ventilation. Staff regularly check kidney function. Many patients can develop kidney problems, so the care team may provide dialysis or other forms of renal support.

Proper nutrition is vital. The team may give nutrition through a feeding tube or an IV to ensure patients receive enough calories, protein, and other nutrients. Managing fluids and electrolytes is a key part of care. Diuretics help remove extra fluid, and doctors carefully monitor fluid levels and blood tests. A summary table of common adjunctive care:

Therapy	Purpose
Mechanical Ventilation	To support breathing and protect lungs.
Nutrition	To provide calories and protein.
Electrolyte Management	To keep salt levels balanced.
Diuretics	To remove extra fluid.
Kidney Support	To help if kidneys are not working.