ECMO stands for Extracorporeal Membrane Oxygenation, a life-support machine that helps pump and oxygenate the patient’s blood outside the body. The ECMO machine mimics the functionality of the human heart and lungs to temporarily replace the cardiopulmonary function of the patient in critical illness. This helps to relax the heart and lungs, which speeds up the healing process.
What is ECMO?
Extracorporeal membrane oxygenation (ECMO) is a treatment that temporarily replaces the functioning of the heart and lungs in critical conditions. ECMO temporarily takes over the work of the heart and lungs, so they can heal from an emergency or critical situations like heart or lung failure.
ECMO is a life-saving procedure that helps the heart and lungs to heal, but it's not a cure for lung and heart diseases. ECMO machine works by extracting blood from the patient and pumping that blood through an artificial lung, exchanging oxygen and carbon dioxide, then sending the blood back to the patient via a pump that takes over the work of the heart.
Why is ECMO used?
ECMO can be used in any age group, from infants to adults who are in critical conditions of the heart, lungs, or who are recovering from heart transplantation.
Some heart conditions which ECMO can be used include:
- Life-threatening response to infection
- Birth defects of the heart
- Low body temperature
- Myocarditis
- Post-transplant complications
- Acute myocardial infarction
- Heart muscle disease
- cardiogenic shock
Some heart conditions which ECMO can be used include:
- Congenital diaphragmatic hernia or Defect in the diaphragm
- Coronavirus disease (COVID-19)
- Blockage in a pulmonary artery in the lungs
- Acute respiratory distress syndrome
- Meconium aspiration syndrome (MAS)
- Extreme high blood pressure in the arteries of the lungs (PPHN)
How does ECMO Machine work?
The ECMO machine is connected to a patient through plastic tubes called a cannula into large veins and arteries in the leg, neck, or chest. ECMO Machine works by removing blood from the patient and pumping that blood through an artificial lung, replacing oxygen and carbon dioxide, then sending the blood back to the patient via a pump that takes over the functioning of the heart.
What are the different modes of ECMO?
ECMO is used in two different ways depending on the patient’s requirement:
Veno-Arterial ECMO(VA - ECMO)
Veno-Arterial ECMO (VA ECMO) is one type that supports both lung and heart function. Two cannulas are placed one in a large vein and the other in a large artery, on the side of the neck, directly into the chest or in the leg. The ECMO machine will take the blood out of the vein, add the oxygen and remove the carbon dioxide, and then return the blood to the artery and pump the blood through the body.
Veno-venous ECMO (VV- ECMO)
Veno-Venous ECMO (VV ECMO) is another type that only supports lung function. One or two cannulas are placed in large veins on the side of the neck or in the leg. Whether to place one or two cannulas depends on the condition of the patient. It pumps blood through the heart to arteries that carry the oxygenated blood to organs and other body tissues, so that the lungs get enough rest and recover soon.
What happens to patients while on ECMO?
Monitoring patients during ECMO
Patients who are on the ECMO will be on continuous observation to measure their heart rate, blood pressure, and oxygen levels. The blood is tested frequently to check the carbon dioxide and oxygen levels in the blood and to make sure the blood is thin enough. All these tests are done to make sure the ECMO machine is helping the patient’s health and to make changes if needed.
Preventing lung infections during ECMO
Sometimes patients develop lung infection in mucus formation. With a tube called an endotracheal tube (ET tube), the mucus is sucked out of the lungs. This helps the lung free from mucus and infection.
Healing the lungs while on ECMO
When the patient is on the ECMO machine, it takes over the lung functioning temporarily and helps in healing the lungs.
Allowing action during ECMO
Medication is given to the patients to reduce the pain and make them comfortable. These medicines may make them sleepy, while some patients are awake and able to talk and interact while on ECMO. Sometimes, patients are active and able to walk while on ECMO.
Nutrition during ECMO
Nutrients provided to patients come from different sources including, central venous nutrition (CVN) and lipids (CVN supply required vitamins, electrolytes, and lipids supply fats) medication is given through a vein. For some patients who have Endotracheal Tube (ET tube), the nutrients are given in the liquid form directly into the stomach through a tube.
What is the risk of ECMO?
Though ECMO is a life-saving procedure, it can be associated with a few risks due to its complexity, which includes:
Bleeding
A blood-thinning medication is needed for the patients while on ECMO, due to this they can start bleeding in different parts of their body (brain, lungs, insertion sites of the cannula). As bleeding can be very serious, the patient will be given certain medications to help the blood clot. In some cases, surgery is needed to stop the bleeding. Blood and blood platelets are given to the patient if the blood count drops.
Blood clot (thromboembolism)
Sometimes blood clots or air bubbles appear inside the ECMO tubes. So, the healthcare team frequently monitors for preventing blood clots or air bubbles while the patient is on ECMO. A medicine called heparin helps the blood from clotting. This helps in reducing the chance of an air bubble reaching organs or a blood clot blocking a blood vessel, so that blood can reach an organ.
Infection
The infection can develop from the sites where the tubes enter the body and can spread to the lungs, or the other body parts. If any signs of infection are identified, the patient will be given antibiotics.
Stroke
When a patient is on ECMO, certain areas of the brain may not get as much blood flow as they need because of small blood clots, this can cause a stroke and some parts of the brain may be damaged permanently. The damaged part of the brain determines what problem a person may develop due to stroke. A stroke may restrict one's capability to move certain parts of their body, see, remember, speak, read, or write. Only a few people who were affected by the stroke may recover function after stroke. Strokes are very rare and happen to less than 5% of the people on ECMO.
Conclusion
ECMO is a complex yet life-saving procedure that potentially benefits patients in critical conditions. However, the success rates of ECMO depend on the severity of the patient’s health condition that has led to the need for ECMO. The doctor will explain to what extent the ECMO can be helpful according to the patient's condition.
