Extracorporeal membrane oxygenation (ECMO) for severe acute lung failure

ECMO stands for extracorporeal membrane oxygenation and can be used to treat adults and babies with severe lung and heart problems. 

What is ECMO?

During ECMO a machine pumps the patient's blood from a large vein through an artificial lung (the membrane), which is outside the body (extracorporeal). This artificial lung adds oxygen to the blood and removes waste carbon dioxide. 

The patient's blood is then returned to their body into another large vein near the heart. It is very similar to the heart–lung machine that is used for patients having an operation on their heart.

Why is ECMO being considered?

Our bodies need oxygen to survive. Lungs that are working normally allow oxygen to pass from the air we breathe into the blood, and our bodies then use this oxygen. The lungs also get rid of waste carbon dioxide when we breathe out. 

When lungs are extremely damaged, they are unable to pass enough oxygen into the blood and get rid of enough carbon dioxide. Patients may be already linked to a breathing machine (or ventilator) which is helping but not enough. 

More than half of patients who become so unwell that they need high levels of support from the ventilator and high levels of oxygen do not survive. ECMO may help these patients to stay alive and give their lungs more time to get better. 

What is the potential advantage of ECMO?

While often life saving, if ventilators are used to give large amounts of oxygen at high pressure they can damage lungs even more.

The aim of ECMO is to supply the body with enough oxygen and remove enough carbon dioxide from the blood.

Breathing machines are still used during ECMO but the doctors are able to turn the oxygen and pressure levels down, which allows the lungs to rest and heal.

Is ECMO effective?

ECMO has been proven to be very effective in treating newborn babies with severe breathing problems.

A study carried out at Glenfield Hospital in Leicester showed that ECMO also works successfully in some adults. The study monitored patients with very severe lung problems and showed that patients who were moved from local hospitals to a specialist ECMO centre were more likely to survive without severe disability.

About 70 per cent of patients with severe breathing difficulties in intensive care who received ECMO during the swine flu pandemic survived. This is more than would have survived without ECMO.

The National Institute for Health and Care Excellence (NICE) has produced a summary of the benefits and risks of ECMO.

The survival rate of patients who were treated with extracorporeal membrane oxygenation (ECMO) was higher than the international average.

Care Quality Commission, 2017

Why is ECMO not available at local hospitals?

ECMO is only available at a few specialist hospitals in the UK (including Royal Brompton Hospital) because this treatment needs specialist equipment and specially trained staff.

Because ECMO is only carried out at a few specialist hospitals it allows staff to become very skilled and knowledgeable about the treatment.

When patients are moved to specialist centres, it does not mean there is anything wrong with the care they have received at their local hospital.

How do patients get from their local hospital to Royal Brompton Hospital?

Hospital staff will arrange for the ECMO team to bring patients to Royal Brompton Hospital.

Patients are usually brought by road ambulance or, sometimes, air ambulance. Relatives will not be able to travel with patients because of limited space and medical staff will need to concentrate on their patient. If the transfer is by road, we strongly advise relatives not to follow directly behind the ambulance as this can be dangerous.

There is a risk involved in moving patients who are very unwell. It is possible that they may become more unwell during the journey. However, the risks of moving a patient are outweighed by the advantages of coming to a hospital with staff skilled in ECMO treatment. 

What happens when the transport team arrive?

The doctor from the ECMO team will carefully assess the patient and check that ECMO is suitable. The team will also explain the patient's condition to the relatives and may ask about the patient's medical history. They will then prepare to transfer the patient to the ECMO centre. It is possible that the medical staff may have to insert extra drips or tubes.

Sometimes, the ECMO team will have to start treatment at the local hospital before moving the patient to the ECMO centre. However, the patient will still need to be taken to the ECMO centre for ongoing treatment.

What happens at the ECMO centre?

Patients are re-assessed on arrival to the ECMO centre. If their condition has improved, the team may decide to treat them without using ECMO. However, ECMO treatment will usually still be necessary.

ECMO is started after a small operation, which is done under a full general anaesthetic. During the operation, doctors insert tubes into veins in the neck and sometimes into the groin. These tubes allow blood to be pumped into the ECMO machine where oxygen is added and carbon dioxide is removed. 

While ECMO is carried out, patients stay attached to the ventilator and are kept asleep on the intensive care unit (ICU). On average, patients need ECMO for five to 14 days. Sometimes they may need to stay on treatment for several weeks. 

Patients will continue to have their other treatments on ICU while they are on ECMO.

Are there any risks associated with ECMO?

The main risk during ECMO treatment is bleeding. This is because a blood-thinning medicine called heparin must be given during treatment. Heparin prevents the blood from clotting in the ECMO machine, which would stop the ECMO from working.

Minor bleeding is common and, although this may look unsightly, it is usually not of major concern.

More serious bleeding occurs in about one in every ten patients. If bleeding occurs inside a patient's brain, it may be fatal. We closely monitor the amount of blood-thinning medicine required to reduce the risk of serious bleeding problems.

There is a small risk of damage to the heart or blood vessels when tubes are inserted into veins in the neck or groin. The risk is reduced by inserting tubes under X-ray guidance.

Are relatives allowed to stay with patients?

The nurses will inform relatives about visiting times. When patients need a wash or a rest, relatives may be asked to leave.

We understand that relatives may be a long way from home and we will try and help with accommodation. Our social worker may also be able to help with claiming travel and living expenses.

Hospital psychologists and religious ministers are available if their help is needed during this difficult time.