ECMO stands for Extra Corporeal Membrane Oxygenation. Extra-corporeal means ‘outside the body’, a membrane oxygenator is a piece of equipment which delivers oxygen into the blood. The ECMO machine is similar to the heart-lung bypass machine used for open heart surgery.
Consequently ECMO is the use of an artificial lung (membrane) located outside the body (extra corporeal) that puts oxygen into the blood (oxygenation) and continuously pumps this blood into and around the body.
University Hospitals of Leicester provides ECMO support for babies and children at Leicester Royal Infirmary site and for adult patients at Glenfield Hospital site.
Extracorporeal membrane oxygenation (ECMO) is a technique for providing respiratory and cardiac support to patients.
In babies, children and adults with very poor cardiac function, ECMO can take over the work of the patient's heart. This provides time for the heart to rest and recover, while maintaining a good blood supply to the brain and other organs in the body. Cardiac ECMO may be needed after open heart surgery, when the heart may be swollen, unable to maintain a high enough blood pressure or have an irregular rhythm. It may also be needed due to an infection affecting the heart muscle (myocarditis) or heart muscle failure (myopathy) where the heart cannot pump blood around the body effectively.
Please note that ECMO can only help patients whose lung and/or heart disease is reversible within approximately three weeks.
In babies, children and adults with very severe lung disease which is not responding to the usual treatment of mechanical ventilation (breathing machine), medicines and extra oxygen, ECMO can take over the function of the patient's lungs, allowing them time to rest and recover.
Types of ECMO
There are two types of ECMO, Veno-arterial (VA) and Veno-venous (VV):
Two cannulae (tubes) are placed into the patient's blood vessels, one into a vein and the other into an artery, usually on the side of the neck. Dark blood (containing little oxygen) is drained continuously into the ECMO circuit from the tube in the vein while the now oxygen-rich blood from the ECMO circuit is returned to the body through the tube in the artery.
This type of ECMO provides support for both the heart and the lungs and so can be used for patient's requiring either cardiac or respiratory ECMO support. For the small number of patient's who require ECMO after open heart surgery, the cannulae (tubes) may be inserted directly into the heart through the chest during the heart operation rather than into the neck vessels.
A single catheter is placed into a vein, usually in the side of the neck. Blood is drained from this catheter into the ECMO circuit at the same time as oxygenated blood is returned through the same catheter from the ECMO circuit to the patient. VV ECMO provides lung support only and does not support the heart.
A few patients who start with VV ECMO will need to be changed over to VA ECMO if their heart also starts to need support.
Who will take care of me / my child?
You / Your child needs specialised care which will be provided by a variety of different people within the ECMO team:
The ECMO clinical nurse specialists are experienced intensive care nurses who are trained in ECMO management. They are responsible for the safe running of the ECMO circuit and one of the team will be at you / your child’s bedside for 24 hours a day while they are on ECMO support. The intensive care consultant, ECMO doctors and ECMO Coordinator will coordinate you / your child’s care and will discuss plans and update you on a regular basis, giving you a chance to ask questions.
Other members of the team who may help care for you / your child include:
Cardiac surgeons, Cardiologists, Physiotherapists, Perfusionists (specialists in heart bypass and ECMO equipment) , Physiotherapists, Theatre nurses, Pharmacists, Psychologist, Dietitians, Radiologist, Pharmacists.
What to expect:
When you first see a paitent receiving ECMO support it can come as a shock. At first all you may see are the various tubes, drips and machines. The nurses will explain the purpose of each one. There may be bleeding around the cannula sites and the patient may look pale and blotchy. If the patient has had a heart operation, the chest may be left open to allow the cannulae to be inserted, but the area will be covered in a dressing and gauze. Let us know if you want this area covered while you are visiting.
Patients on ECMO can also appear quite swollen and puffy especially around the face, hands and feet. This can happen after a heart operation but can also occur if they were given a lot of intravenous fluids before ECMO was started. We will give the patient medications to encourage the kidneys to pass larger volumes of urine, which should reduce the swelling gradually.
Most patients will remain on some respiratory support whilst on ECMO.
If on ECMO for heart support only, the ventilator will maintain a normal breathing pattern, keeping the lungs in good condition. If on ECMO for lung support, only very gentle ventilation will be given to enable the lungs to rest, but be supported in their recovery. The endotracheal (ET) tube which helps the patient's breathing may have to be changed. The medical team will explain the reason for this procedure with you.
We hope to see a gradual recovery over a few days or weeks. Once athe patient is off ECMO, they will continue to need ventilator support for a time.
How long can a patient stay on ECMO support?
The average length of ECMO support is five to ten days but some patient's will need longer. The length of support depends mainly on the type of lung or heart problem. Sadly, in some cases, it becomes clear that ECMO is not helping and if this is the case, we will fully discuss the problems with you.
What are the risks of ECMO?
ECMO is only used for very sick patients who would die without ECMO support. There are risks associated with ECMO support, which are briefly outlined below and will be explained to you in more detail by the ECMO team. Not everyone on ECMO will experience these complications, but they are a possibility so we want you to be aware of them. These are bleeding, infection, neurological and renal complications and circuit complications.
Blood is designed to clot if it leaves the body or comes into contact with foreign surfaces such as the plastic of the ECMO circuit. Usually this mechanism keeps us safe by stopping us bleeding if we cut ourselves. However, on ECMO, it is important that we prevent clots from forming within the ECMO circuit and so a blood thinning drug called heparin is used. The disadvantage of this is that heparin prevents blood clotting effectively not only in the ECMO circuit but throughout the body. This means that bleeding can occur around any wound or site where any tube or needle was inserted. It can also occur around the nose and mouth.
Bleeding is very common when ECMO is used following cardiac surgery. If bleeding occurs, the patient may need a surgical exploration of their chest by the cardiac surgeon. This takes place in the Intensive care unit at any time of day or night and may be needed every day or two. The patient will have a general anaesthetic during the procedure, so they will not feel any pain or discomfort. We will tell you about any chest explorations needed, but will ask you to leave the intensive care unit while it is carried out. We will let you know when it is finished and you can visit again – the exploration usually takes about two hours.
There is a risk of infection with any invasive procedure, especially when tubes are inserted into blood vessels, as they give a direct route into the blood stream. We will monitor the patient closely for any signs of infection and give antibiotics if needed.
Neurological (involving the brain)
When the blood in the body is thinned, as it is on ECMO, the risk of bleeding into the head is increased. Newborn babies are already at risk from this, and the risk increases further with ECMO. Sometimes brain problems can happen due to your child’s condition before going on ECMO, rather than ECMO itself.
Renal failure is an additional problem which may be seen on ECMO. If this occurs another machine can be connected to the ECMO circuit which acts as an artificial kidney until your child’s own kidneys start working again.
ECMO circuit complications
Although the circuit is monitored continuously and checked on a regular basis for clots and other problems, complications can still occur. The ECMO team are trained to deal with these situations and can often anticipate problems which they can then prevent.