Extracorporeal Membrane Oxygenation
ECMO or extracorporeal membrane oxygenation involves pumping the blood outside from your body into a heart-lung machine. The machine removes carbon dioxide and pumps back oxygen-filled blood into your body tissues. The flow of the blood is from the right side of your heart to the membrane oxygenator of the heart-lung machine that rewards and sends it back to your body. The procedure allows the organs to rest and heal while the blood bypasses your heart and your lungs. Usually used in infants with critical disorders of the heart and the lungs, you may also find its use for some other infections.
The method involves the use of a membrane oxygenator (acting as an artificial lung) that oxygenates the blood. It supplies oxygen to the blood and returns it to your body by combining with a warmer and a filter. Used for providing oxygenation while your doctor treats the disorder, it also benefits adults and older children.
Types and parts of ECMO
ECMO is of two types:
- Veno-venous ECMO (VV ECMO)- It takes blood from the veins and returns the blood to the vein. This type of ECMO finds its application in supporting lung function.
- Veno-arterial ECMO (VA ECMO)- It takes up the blood from one of the veins and returns the blood back to the artery. It supports the lungs as well as your heart. Being more invasive than veno-venous ECMO, there might be a need to close off the carotid artery (carotid artery is the main artery that extends from the heart to the brain).
Parts of ECMO include:
- Cannulae- They are large tubes (catheters) that your doctor will insert into your blood vessels for taking up and returning the blood back to the body.
- Membrane oxygenator- Used for oxygenating the blood, it is an artificial lung.
- Warmer and filter- Its purpose is to warm and filter your blood before the cannulae or catheters return the blood back to your body.
The cannulae take up blood with less oxygen from your body and send it to the oxygenator during ECMO. The membrane oxygenator will then pump oxygen into your blood and send this oxygenated blood through the warmer & filter to finally return the blood to your body.
Reasons for ECMO
ECMO is for the people suffering from critically ill conditions of the heart and the lungs or recovering from a heart transplant and when other life support procedures didn’t work. If you are suffering from serious but reversible lung or heart disorders, then your doctor will place you on ECMO. For the newborns, it is beneficial as it allows their heart and lungs to develop. There is a substantial increase in the survival rates with ECMO. It helps your body by providing oxygen to your body tissues. You may need to go for ECMO during conditions enlisted here.
- ARDS (Acute Respiratory Distress Syndrome)
- Congenital diaphragmatic hernia (if there is a defect in the diaphragm)
- Pulmonary hypertension (high blood pressure present in the lungs)
- Respiratory failure
- Sepsis (an infection that can be life-threatening)
For older children:
- Severe pneumonia
- Cardiac surgery
- Toxic materials present in the lungs because of aspiration
- Congenital heart defects
- Decompensated cardiomyopathy (heart muscle disease)
- Severe hypothermia (low body temperature)
- Acute myocardial infection (heart attack)
- Carcinogenic shock (shock caused when the heart is unable to pump enough blood)
- Myocarditis (presence of inflammation in the muscles of the heart)
- Post-transplant complications
- Pulmonary embolism (blockage in the pulmonary artery of the lungs)
- Hantavirus pulmonary syndrome
- Influenza (flu)
Preparation for ECMO
Your doctor will first check you before placing you on ECMO. He or she will perform a cranial ultrasound of your brain to ensure that there’s no bleeding. It will also determine if your heart is working. You might need to undergo a chest x-ray daily while on ECMO. Your doctor will prepare the equipment after determining if you need ECMO. A trained team will perform your ECMO. The team will include respiratory therapists, ICU registered nurses, consultants & support personnel, rehab specialists, perfusionists who specialize in performing ECMO and a 24/7 transport team.
What to expect?
During ECMO, your doctor will first discuss all the details of the procedure with you and/or your family. Your doctor will place the cannulae in your chest, neck or groin region depending on your age after giving you general anesthesia (sleep medicine). You will be sleeping due to the sedation while being on ECMO. ECMO will perform the function of the lungs or heart. Your doctor will monitor you closely during ECMO with the help of daily X-rays. Apart from this, the doctor will also be monitoring your:
- Blood pressure
- Heart rate
- Oxygen levels
- Respiratory rate
With the help of a ventilator and a breathing tube, your lungs will continue to work and remove the secretions from your body. You will continuously receive all the medications through intravenous catheters including heparin. Heparin prevents the clotting of blood while it travels during ECMO as it is a blood thinner. Your doctor will place you on ECMO for a minimum of three days to even a month, depending on your condition. However, the higher you are on ECMO, the higher is the risk associated with ECMO.
After noticing the improvements in your condition, your doctor will slowly reduce the amount of oxygenated blood that you receive through the ECMO and then wean you off from ECMO. Once you get off from this, your doctor will place you on a ventilator for a certain period of time. However, you will still require a regular follow-up for monitoring the underlying condition.
Results of ECMO
Risks of ECMO
The most common risks associated with ECMO are:
- Coagulopathy (blood clotting disorder)
- Stroke (damage to the brain because of the bursting of blood vessels or blood loss)
- Thromboembolism (blood clot)
- Limb ischemia (loss of blood in the limbs)