Extracorporeal membrane oxygenation is a type of invasive treatment method, during which blood is pumped out of the body through an extracorporeal pump and returned back to the body fully oxygenated. In this way, it can partially or fully replace function of an impaired heart and/or lungs. This type of treatment is suitable for patients with severe cardiac/pulmonary dysfunction.
ECMO is used when standard types of invasive treatment are not successful. It does not treat heart and lung disease, but only provides time for the patient’s heart or lungs to recover or to provide time to final decision whether the patient could benefit from organ transplantation. In rare cases, ECMO can also be used as a method of resuscitation in patients with cardiac arrest.
ECMO is used in intensive care and heart surgery. It can replace/support the function of the heart/lungs from a few hours to a few weeks.
A doctor inserts a plastic-metal tube called cannula into a large vein or artery. These large blood vessels are located in the neck, groin, or chest. A various number of cannulaes can be inserted, depending on which type of treatment ECMO is being used for. The cannulaes are connected to tubing system made of artificial material that allows blood to flow from the body and back into it.
Pump is the part of the ECMO system that pumps blood through ECMO system from the body and sends it back. It drains blood with low oxygen saturation and pumps it through an artificial lung (oxygenator). There, carbon dioxide is removed from the blood and blood is saturated with oxygen. This turns dark red blood into light red, which then flows to the other side of the ECMO system and is returned to the patient through a cannula.
Since ECMO saturates blood with oxygen and removes carbon dioxide, doctors can lower the settings on the standard mechanical ventilator, thus allowing the lungs to rest and heal. By pumping the blood through the body, the pump also reduces the heart workload. Drug doses, which are used to support the heart function and may be harmful in the long term, can be lowered or even discontinued during ECMO.
Patients with severe respiratory failure, which is most commonly caused by:
Patients with severe cardiac dysfunction, which is most commonly caused by:
Patient monitoring during ECMO therapy:
We regularly monitor the heart and lung status and check the position of the cannulae with an X-ray, as well as perform blood tests several times a day. Other tests can also be performed if necessary.
Pain treatment during ECMO:
We usually give patients drugs which calm them down and reduce pain. At the start of ECMO therapy, patients are often sedated.
Preventing blood clot formation and bleeding during ECMO:
We usually use a drug called heparin, which prevents blood clotting, because blood can clot quickly when it comes into contact with artificial materials. In this way, heparin prevents blood clots from forming in the ECMO machine. As it increases the risk of bleeding, it is necessary to carefully monitor blood clotting tests and the patient.
ECMO patients often require blood transfusion.
Most ECMO patients are mechanically ventilated – they have a tube called endotracheal tube placed in trachea. The tube is connected to a ventilator; a machine that ventilates the lungs.
Preventing and treating infections:
Since infections are common, so is treatment with antibiotics. It is highly important to avoid contact with sick people in order to prevent infections from spreading.
Nutrition during ECMO:
Most patients are fed through a tube, which is inserted into the stomach through the mouth or nose to deliver liquid food that contains all the important nutrients.
ECMO patients can undergo surgical or other invasive procedures if necessary.
These patients are managed by specially trained doctors and nurses in intensive care units who are fully familiar with the functioning of ECMO system. They are trained in dealing with such patients who are the most challenging in terms of intensive care. Physiotherapists are also very involved in the treatment process, particularly in the phase when the patient’s status is improving.
Patients are sedated and receive analgetic therapy at least in the first days after being connected to the ECMO machine. The patient has a tube inserted for mechanical ventilation. The patient will also have tubes for administering therapy, supplying nutrition and measuring vital functions, as well as a urinary catheter. The patient is connected to a monitor, which allows us to monitor all vital functions. ECMO machine is beside the patient, whose blood flows through the machine via tubes. The patient can sometimes also be connected to other machines used to maintain vital functions (intraaortic balloon pump, dialysis machine). ECMO patients can appear swollen for the first few days, which is usually a consequence of reduced renal function and fluid therapy. If renal function does not suffice to maintain fluid balance, dialysis treatment is necessary.
The most common complication is bleeding. Bleeding can be internal or external and is most dangerous when it occurs in the brain. Infections, which are treated with antibiotics, are also common. We must be very careful to prevent any air from entering the system, as air bubbles can cause infarctions in the body. Similarly, formation of blood clots can present a threat to the patient due to infarctions or because they can stop the functioning of the ECMO system on which the patient depends.
ECMO therapy is challenging and often lasts for a long period of time. It is extremely strenuous for the patient and their loved ones. It is the patient’s relatives who are often extremely burdened due to the lengthy treatment, possible complications, and uncertain outcome. It is important that they understand what is happening with their loved one, which is why we strive for the best possible communication to inform them of the patient’s status as best as possible. Sometimes relatives require psychological support in order to deal with this difficult period.
Presence of family members and their encouragement are, however, extremely important for the patient. This is particularly true during the recovery phase, which is often slow and requires an enormous amount of willpower and a positive approach, both from the family and, of course, the patient.