Types of Pediatric ECMO: Heart Support vs Lung Support — What’s the Difference?

Medicine Made Simple Summary

There are two main types of pediatric ECMO: VV ECMO for lung support and VA ECMO for heart and lung support. VV ECMO takes blood from a vein and returns it to a vein, helping children whose lungs cannot add enough oxygen. VA ECMO returns blood to an artery, giving both the heart and lungs time to recover when circulation is too weak. The type chosen depends on whether the child’s main problem is breathing failure, heart failure, or a combination of both.

Why Understanding ECMO Types Helps Parents Make Sense of Treatment

Hearing that your child needs ECMO can be overwhelming. The equipment looks complex, the medical language feels unfamiliar, and decisions must often be made quickly. One of the first questions parents ask is what type of ECMO their child needs. Doctors may mention “VA ECMO” or “VV ECMO,” but understanding these terms helps families feel more confident and informed.

The two types of ECMO—heart support and lung support—work differently. Each is chosen based on what part of the child’s body needs help the most. Learning how they differ helps parents understand what doctors aim to support, how long recovery may take, and what to expect in the ICU.

The Purpose of ECMO: A Quick Refresher

Why ECMO Is Used

ECMO provides temporary life support when the heart or lungs cannot function well enough on their own. It moves blood outside the body, adds oxygen, removes carbon dioxide, and pumps it back in. This gives the organs time to rest and heal.

Two Different Needs: Heart vs Lung Failure

Some children struggle mainly with breathing. Others struggle with circulation. Sometimes both systems are affected. The type of ECMO chosen depends on which organs are failing.

VV ECMO: Support for the Lungs

When VV ECMO Is Used

VV ECMO is used when a child’s lungs need support but the heart is working well enough. It is the preferred option for breathing-related conditions because it avoids unnecessary support to the heart.

Common situations include

• Severe viral or bacterial pneumonia
• ARDS (acute respiratory distress syndrome)
• Lung injury from infection or inflammation
• Meconium aspiration in newborns
• Severe asthma unresponsive to treatment

How VV ECMO Works

VV ECMO takes blood from a vein, passes it through the ECMO machine to add oxygen and remove carbon dioxide, and returns it to a different vein. Once the oxygen-rich blood returns to the body, the heart pumps it out to organs and tissues.

Why VV ECMO Protects the Lungs

Ventilators can sometimes cause strain or injury when lungs are very inflamed. VV ECMO reduces the need for high ventilator settings. This gives the lungs time to rest and recover.

Where Cannulas Are Placed

Cannulas for VV ECMO are usually placed in large veins in the neck or groin. Newer double-lumen cannulas allow blood to enter and exit through a single site, often reducing the need for larger tubes.

What VV ECMO Cannot Do

VV ECMO cannot support the heart. If the heart becomes too weak, VV ECMO must be switched to VA ECMO.

VA ECMO: Support for the Heart and Lungs

When VA ECMO Is Used

VA ECMO is chosen when both the heart and lungs need support or when the heart cannot pump enough blood to the body. Children on VA ECMO are typically more critically ill because two organ systems are affected.

VA ECMO is used for

• Heart failure
• Cardiac arrest requiring ECPR
• Severe congenital heart disease
• Complications after heart surgery
• Sepsis with heart dysfunction
• Cardiomyopathy

How VA ECMO Works

VA ECMO takes blood from a large vein and returns it through an artery. This means the ECMO pump helps push blood through the body, supporting circulation directly. It replaces much of the workload of the heart.

Why VA ECMO Protects the Heart

When the heart is weak or injured, pushing blood through the body can make the situation worse. VA ECMO reduces this strain, giving the heart a chance to rest and recover.

Where Cannulas Are Placed

Cannulas may be placed in the neck, groin, or chest. After heart surgery, cannulas may be placed directly into the heart or major blood vessels.

What VA ECMO Cannot Do

VA ECMO supports circulation and oxygenation, but it cannot cure the underlying heart problem. Recovery depends on treatment of the cause, such as infection, inflammation, or surgical repair.

Key Differences Between VV and VA ECMO

1. What Each Type Supports

• VV ECMO supports only the lungs.
• VA ECMO supports both the heart and lungs.

This is the main distinction. If the heart is functioning well, VV is used. If the heart is failing, VA is chosen.

2. How the Blood Travels

• In VV ECMO, blood goes from a vein to a vein.
• In VA ECMO, blood goes from a vein to an artery.

The return location determines how much help the child receives.

3. Impact on Heart Function

• VV ECMO does not change the workload of the heart.
• VA ECMO reduces how much work the heart must do.

Because VA ECMO takes over circulation, it is used for more severe conditions.

4. Assisted Organ Recovery Time

• Lung recovery on VV ECMO may take days to weeks.
• Heart and lung recovery on VA ECMO can take longer because two systems are healing at once.

5. Risks and Considerations

• VA ECMO carries slightly higher risks because it supports more organs and involves arterial cannulation.
• VV ECMO focuses on respiratory issues and tends to have fewer circulation-related complications.

Examples That Help Parents Understand the Difference

Example 1: Lung Failure Only

• A child with severe pneumonia has dangerously low oxygen levels even with a ventilator. The heart is pumping well.
• Doctors choose VV ECMO because the main problem is oxygenation.

Example 2: Heart Failure After Surgery

• After repairing a congenital heart defect, a child’s heart struggles to pump blood.
• Doctors choose VA ECMO because the heart needs time to recover.

Example 3: Cardiac Arrest

• A child experiences cardiac arrest, and CPR is not restoring stable circulation.
• Doctors initiate VA ECMO to help restart and maintain blood flow.

Example 4: ARDS After a Viral Infection

• A child with ARDS has stiff, inflamed lungs. The heart is stable.
• VV ECMO is chosen so the lungs can rest.

These examples help families visualize when and why each ECMO type is chosen.

How Doctors Decide Between Lung Support and Heart Support

Evaluating the Child’s Condition

• Doctors assess
• Heart function
• Lung function
• Blood oxygen levels
• Blood pressure and circulation
• Response to previous treatments

A child who cannot oxygenate but has strong circulation needs VV ECMO. A child who cannot pump blood effectively needs VA ECMO.

Considering Future Treatment Plans

If heart surgery is planned soon, doctors may choose VA ECMO. If lung healing is expected, VV ECMO is preferred.

Monitoring During ECMO

Sometimes a child starts on VV ECMO and later needs VA ECMO. This happens if the heart becomes weaker over time.

Recovery Differences Between VV and VA ECMO

Recovery After VV ECMO

Recovery focuses mainly on lung healing. Children may need ventilator support even after ECMO is removed. Many gradually improve as lung inflammation decreases.

Recovery After VA ECMO

Recovery involves rebuilding both heart and lung strength. Some children may need additional heart treatments, medications, or even another surgery.

Long-Term Outlook

Most children who receive either type of ECMO recover well if the underlying condition improves with treatment. Long-term outcomes depend more on the disease than on the ECMO itself.

Conclusion

If your child is being evaluated for ECMO, ask your care team which type of support they are recommending and why. Understanding the difference between heart support and lung support helps you feel more prepared during a stressful time. Your doctors can explain what to expect, how the machine will help, and what signs they look for during recovery.