What is ECMO(Extracorporeal Membrane Oxygenation)?
In intensive care medicine, extracorporeal membrane oxygenation (ECMO)is an extracorporeal(outside of the body) technique of providing both cardiac and respiratory support oxygen to Patients whose heart and lungs are so severely diseased or damaged that they can no longer serve their function. Initial cannulation(insertion of a cannula) of a Patient receiving ECMO is performed by a surgeon and maintenance of the Patient is the responsibility of the ECMO Specialist and gives 24/7 monitoring care for the duration of the ECMO treatment. Because the heart and/or the lungs are so sick and unwell that these major organs stopped working properly and they are therefore unable to provide oxygen and blood to all the other important organs in the body, ECMO may be the treatment of choice for lung and/or for heart failure and ECMO may be a bridging therapy and/or a stepping stone towards organ transplantation for the lungs(Lung Transplantation) and/or the heart(Heart Transplant).
When is ECMO used?
Guidelines that describe the indications and practice of ECMO are published by the Extracorporeal Life Support Organization (ELSO). Criteria for the initiation of ECMO include acute severe Heart Failure or pulmonary failure(also Adult Respiratory Distress Syndrome (ARDS)) that is potentially reversible and unresponsive to conventional management. Examples of clinical situations that may prompt the initiation of ECMO include the following:
- Hypoxic(lack of oxygen) respiratory failure, despite optimization of the ventilator settings, including the fraction of Inspired Oxygen (FiO2)
- Cardiogenic Shock
- Cardiac Arrest
- Failure to wean from cardiopulmonary bypass after cardiac surgery(Coronary Artery Bypass Graft (CABG))
- As a bridge to either cardiac transplantation(Heart Transplant) or placement of a ventricular assist device(Ventricular Assist Devices)
When is ECMO not used?
Most reasons to not use ECMO are relative, balancing the risks of the procedure (including the risk of using valuable resources which could be used for others) vs. the potential benefits. The relative reasons for not using ECMO are:
- Conditions incompatible with normal life if the Patient recovers
- Preexisting conditions which affect the quality of life (CNS status, end stage tumours, risk of systemic bleeding with anticoagulation)
- Age(+/- >65) and size of Patient
- Futility: patients who are too sick, have been on conventional therapy too long, or have a fatal diagnosis
How Does ECMO Work?
Extracorporeal means ‘outside the body’. The ECMO machine in principal works like a Bypass machine(oxygenator) and is capable of exchanging oxygen and carbon dioxidin the blood of a human Patient, while critical organs such as the heart or the lungs have stopped working properly. Two large tubes have been surgically inserted into your loved one and if your loved one is in lung failure, the large tubes have been inserted into two veins(ECMO for lung failure is also called V-V ECMO) and if your loved one is in Heart Failure one of the two large tubes is inserted in an artery and the other one in a vein(ECMO for heart failure is called V-A ECMO). The blood coming from your loved one is pumped through the ECMO machine and the blood coming from your loved one is dark in colour (due to high carbon dioxide levels and low oxygen levels). The oxygenator adds oxygen to the blood and helps in lowering the carbon dioxide levels. The blood returning to your loved one is brighter in colour because of the improved oxygen level.
In Patients with Heart Failure V-A ECMO is instigated and dependent on your loved ones condition and pre-medical history he or she might be awake and spontaneously breathing without a ventilator.
In Patients with lung failure V-V ECMO is instigated and your loved one is mechanically ventilated with Ventilators (Breathing Machines) and a Breathing Tube or Endotracheal Tube. It is not uncommon for a Patient with lung failure to have a Tracheostomy inserted for long-term ventilation.
During ECMO the blood will be anticoagulated(thinned) by drugs such as Heparin(called anticoagulants) to prevent the blood from clotting. With the ECMO tubes pumping blood in and out of the body, careful and regular monitoring for infection and bleeding will take place.
ECMO machine used in a critically ill Patient in ICU
How Long Will It Be Used For?
ECMO can be used for a period of several hours to several days. In extreme cases ECMO may be used for several weeks. As the lungs or the heart recover, the ECMO machine will be weaned and removed. In order for the ECMO machine to be removed regular testing of vital parameters such as Cardiac output/ Cardiac Index and Arterial blood gases(ABG’s) are necessary.
Are There Any Complications?
ECMO generally is a relatively risky intervention, with a potential beneficial payoff for the recovering Patient. In adults, ECMO survival rates are around 60%. Nevertheless are there several complications that may occur throughout the ECMO therapy
- subarachnoid hemorrhage
- hypoxic-ischemic encephalopathy
- unexplained coma
- brain death
- Fatal sepsis may occur when the large tubes(catheters) inserted in the neck provide fertile field for infection
- Additional risks include bleeding
- thromboembolism(the formation of a blood clott)
- vessel perforation through the tube(s)
- Heparin-induced thrombocytopenia (HIT)
Of course, if you have any questions or concerns, please discuss them with the ICU nurses and doctors.
All Intensive Care interventions and procedures carry a degree of potential risk even when performed by skilled and experienced staff. Please discuss these issues with the medical and nursing staff who are caring for your loved one.
The information contained on this page is general in nature and therefore cannot reflect individual Patient variation. It is meant as a back up to specific information which will be discussed with you by the Doctors and Nurses caring for your loved one. INTENSIVE CARE HOTLINE attests to the accuracy of the information contained here BUT takes no responsibility for how it may apply to an individual Patient. Please refer to the full disclaimer.