ecmo

What is ECMO

ECMO is short for extracorporeal membrane oxygenation or extracorporeal life support machine, is a treatment that uses a pump to circulate blood through an artificial lung back into the bloodstream of a very ill baby or adult. ECMO provides heart-lung bypass support outside of the baby’s or adult’s body. ECMO provides long-term breathing and heart support and is used only when all of the standard treatments for those problems have already been tried. People who need ECMO have a severe and life-threatening illness that stops their heart or lungs from working properly. ECMO is indicated for respiratory or cardiac failure unresponsive to all other measures, but considered to have a reversible cause. ECMO may help support a child who is awaiting a heart or lung transplant. Most children treated with ECMO are very seriously ill and its use is rare. ECMO may also be used following heart surgery to ease the transition from cardiopulmonary bypass.

ECMO is performed using a heart-lung bypass machine similar to the one used during open heart surgery. The ECMO machine, often referred to as a “circuit,” is quite large and contains sterile plastic tubing that moves blood from your baby to the “ECMO lung” and then back to your child. The ECMO lung adds oxygen to the blood and removes carbon dioxide, as a healthy lung would.

There are two types of ECMO. Venovenous (V-V) ECMO is used when the heart is functioning well and only the lungs need to rest and heal. Venoarterial (V-A) ECMO is used when the heart as well as the lungs need to rest and heal.

The ECMO machine replaces the function of the heart and lungs. People who need support from an ECMO machine are cared for in a hospital’s intensive care unit (ICU). Typically, people are supported by an ECMO machine for only a few hours to days, but may require it for a few weeks, depending on how their condition progresses. There are many overlaps and differences between the use of ECMO in children and adults.

Starting ECMO requires a large team of caregivers to stabilize the baby, as well as the careful set-up and priming of the ECMO pump with fluid and blood. Surgery is performed to attach the ECMO pump to the baby through catheters that are placed into large blood vessels in the baby’s neck or groin. ECMO team has the specific training and expertise in the ECMO procedure.

ECMO indications

ECMO is used during life-threatening conditions such as severe lung damage from infection, or shock after a massive heart attack. ECMO is also used in infants who are sick due to breathing or heart problems.

ECMO is used to help people whose:

  • Lungs cannot provide enough oxygen to the body even when given extra oxygen
  • Lungs cannot get rid of carbon dioxide even with help from a mechanical ventilator
  • Heart cannot pump enough blood to the body

ECMO may also be used to support people with heart or lung disease that cannot be cured while they wait for an organ transplant (e.g. new heart and/or lungs).

ECMO in baby

ECMO is used in infants who are sick due to breathing or heart problems. The purpose of ECMO is to provide enough oxygen to the baby while allowing time for the lungs and heart to rest or heal.

The most common conditions that may require ECMO are:

  • Congenital diaphragmatic hernia (CDH): A condition in which part of the stomach and/or intestines protrude through an opening in the diaphragm into the chest cavity.
  • Respiratory distress syndrome (RDS): a lung condition, usually in premature babies, that makes it difficult for babies to breathe on their own.
  • Birth defects of the heart or congenital heart conditions
  • Meconium aspiration syndrome (MAS): A condition that occurs when meconium, the first stool of a newborn, is inhaled by the baby before or during delivery, and causes lung problems.
  • Severe pneumonia
  • Severe air leak problems
  • Persistent pulmonary hypertension of the newborn (PPHN): A disorder characterized by abnormally high blood pressure in the arteries that supply blood to the lungs.
  • Sepsis
  • End-stage cardiac or respiratory failure (as a bridge to transplant)

ECMO may also be used during the recovery period after heart surgery.

Because babies who are considered for ECMO are already very sick, they are at high risk for long-term problems, including death. Once the baby is placed on ECMO, additional risks include:

  • Bleeding
  • Blood clot formation
  • Infection
  • Transfusion problems

Rarely, the pump can have mechanical problems (tube breaks, pump stops), which can harm the baby.

However, most babies who need ECMO would probably die if it were not used.

ECMO in adults

ECMO for acute respiratory distress syndrome (ARDS) or acute heart failure in adults should only be carried out by clinical teams with specific training and expertise in the procedure.

The evidence on the efficacy of ECMO for acute heart failure in adults is adequate but there is uncertainty about which patients are likely to benefit from this procedure, and the evidence on safety shows a high incidence of serious complications. Therefore, ECMO treatment should only be used with special arrangements for clinical governance, consent and audit or research.

ECMO is a temporary life support technique used to treat acute respiratory distress syndrome (ARDS) (where the lungs do not work effectively) in critically ill adult patients. The aim is to increase oxygen levels in the blood. During the ECMO procedure, a tube carries blood from the right side of the heart then pumps it through an artificial lung where it picks up oxygen. This oxygen-rich blood is then passed back into the person’s blood system.

How does ECMO work?

The ECMO machine is connected to a patient through plastic tubes (cannula). The tubes are placed in large veins and arteries in the legs, neck or chest. The procedure by which a healthcare provider places these tubes in a patient is called cannulation.

The ECMO machine pumps blood from the patient’s body to an artificial lung (oxygenator) that adds oxygen to it and removes carbon dioxide. Thus, it replaces the function of the person’s own lungs. The ECMO machine then sends the blood back to the patient via a pump with the same force as the heart, replacing its function.

The ECMO machine is controlled by a person called a perfusionist, or a nurse or respiratory therapist with advanced training called an ECMO specialist. The perfusionist or ECMO specialist will adjust the settings on the machine to give the patient the amount of heart and lung support they need.

Is ECMO painful?

ECMO life support is generally not painful. Your child will receive pain medications and sedatives during ECMO, and in some cases may require complete muscle relaxation with medications known as paralytics. These medications are only used when it is determined that your child needs to be completely still for safety reasons or during procedures. You will be able to talk to and touch your child while he or she is on ECMO support.

What will my child look like during ECMO support?

Your child may be on a specially designed and elevated bed during ECMO support. Routine monitoring equipment will be connected to measure your child’s heart rate, respiratory rate, oxygen levels and blood pressure. Your child will have a breathing tube inserted through his or her nose or mouth that will be connected to a ventilator, which is needed to prevent your child’s lungs from collapsing while they heal. There will be intravenous catheters in place that will be connected to tubes providing continuous administration of medications. The ECMO pump and circuit will be next to your child’s bed.

How is a patient on an ECMO machine monitored?

Any patient connected to an ECMO machine in the ICU is also connected to monitors. These monitors measure heart rate, blood pressure, and oxygen levels. Patients on ECMO need their blood tested very often to measure the oxygen and carbon dioxide levels.

These tests are called blood gases. Patients on ECMO are also given a medication to thin the blood so it does not clot. Thus, the blood is tested frequently to make sure it is thin enough. Members of the patient’s health care team use all these results to see how well the ECMO machine is helping the patient, and to make changes if needed.

How long is an ECMO machine used?

An ECMO machine can help save a patient’s life, but it does not treat the patient’s disease or injury. An ECMO machine simply provides support for a patient while the healthcare team works on treating the underlying disease or injury (such as an infection) or until organs for transplant become available. Healthcare providers will always try to help people get off the ECMO machine as soon as possible. Some diseases or injuries can be treated quickly, and patients only need the ECMO machine for a few hours. Other conditions may take longer to get better, in which case the patient may need the ECMO machine for several days to weeks. Unfortunately, in some cases, patients do not improve enough to be taken off the ECMO machine. ECMO does not save everyone but it has improved survival for many critically ill people who are not responding to usual life support options.

ECMO support has been continued for up to 25 to 30 days. Long-term ECMO support increases the chances of complications. The decision to discontinue ECMO support is determined after careful evaluation of the patient’s lungs and heart, and their ability to resume near-normal function with minimal support and intervention. Your child’s cardio-pulmonary function will be monitored through chest X-rays, echocardiography and blood tests.

How does it feel to be on ECMO?

When a patient is first being connected to an ECMO machine, he or she is sedated and does not feel the tubes going into their veins and arteries. A person on ECMO is usually already connected to a breathing machine (ventilator) through a tube (endotracheal or ET tube) that is placed in the mouth or nose and down into the windpipe.

Once connected to an ECMO machine, the cannulae are not painful. Patients who are on an ECMO machine may be given medicines (sedatives or pain controllers) to keep them comfortable. These medicines may also make them sleepy. Other patients are awake and can talk and interact with people while on an ECMO machine. In some cases, patients can exercise to help build up their strength while they are on an ECMO machine. However, some movements can cause the ECMO tubes to get kinked, so patients need to be assisted and carefully supervised when they are moving.

How does a patient get taken off ECMO?

The ECMO machine supports the patient while he or she tries to overcome a disease or injury. If the disease or injury improves, the patient may not need the support of the ECMO machine anymore. The healthcare providers will slowly reduce the amount of support the ECMO machine is providing to see if the patient will be okay without it, just like they do with a ventilator. If the patient remains stable (or improves) as this is being done, the ECMO tubes are removed and surgeons stitch the entry spots up to close them.

What happens if a patient cannot be taken off ECMO?

ECMO is only a “life-sustaining treatment.” ECMO does not cure or treat the disease or injury that led to heart and/or lung failure. This means it is a treatment that can prolong life to allow for more time to try to fix the problem. Sometimes patients do not get better while they are on ECMO because their disease or injury cannot be fixed. A decision about whether there is benefit to continuing ECMO can be hard, and some patients will not want to stay on ECMO if they are not improving.

If the healthcare providers believe that the patient’s disease or illness is very severe and will not get better, they will discuss this carefully with the patient and family members and help to make decisions about the end of life and removing the patient from ECMO support. If the patient cannot talk or communicate his or her decision, the healthcare providers will talk with the patient’s legally authorized representative (usually a spouse, parent, or next of kin). While patients can die even though they are connected to ECMO, sometimes ECMO seems to prolong the dying process.

It is important to talk to your family members and your healthcare providers about your wishes regarding end of life and what you would like to happen in different situations. The more you clearly explain your values and choices to your loved ones and healthcare providers, the easier they will be able to follow your wishes if and when you are unable to make decisions for yourself. An advanced directive (or a “living will”) is a way to put your wishes in writing to share with others. In the hospital, nurses, doctors, and social workers can provide information about how to complete an advanced directive form.

What are complications associated with ECMO support?

The most common complication associated with ECMO support is bleeding. Bleeding is prevalent because heparin, a blood-thinning medication, is continuously administered during ECMO. Heparin prevents the formation of blood clots and helps keep the ECMO circuit flowing smoothly. Bleeding may be visible at surgical sites, or it may not be, if it is internal. Every effort is made to minimize the use of heparin and reduce bleeding. The level of blood anticoagulation is monitored every hour at the bedside, and the dose of heparin used is carefully controlled to prevent bleeding complications.

Rarely, serious bleeding in the brain can occur. Infants are particularly susceptible to this kind of complication and therefore are routinely monitored by pediatric neurologists with head ultrasound and other examinations. Infections and problems with liver and kidney function can occur in patients who remain on ECMO over a long periods of time. All vital organs are routinely monitored with blood tests.

Mechanical complications with the circuit or pump also are possible. The ECMO circuit is composed of components that are interconnected to create a smooth-flowing support system for your child. If any of these parts malfunction, there is the risk of significant blood loss and/or the introduction of air into the system. These malfunctions are rare, but if they occur, significant damage may be done to the organs, including the brain. The ECMO specialist is trained to manage all ECMO-related emergencies.

There are potential long-term problems that can occur, such as developmental and neurologic disorders. Neurologic problems have been associated with low oxygen levels to the brain prior to ECMO, or intracranial hemorrhage. Your child’s physician will discuss long-term problems that may occur as a result of your child requiring ECMO support. The Neurology Department will provide ongoing follow-up after your child has been discharged.

What can I do for my child while on ECMO?

Perhaps the most important thing you can do during this difficult time is to be in the room with your child as much as you can. Your child will be sleepy most of the time, but hearing your voice and knowing that you are there can be tremendously helpful. Your child will require rest, but there may be times when reading a story, playing music or just talking to your child may be very helpful. You won’t be able to hold your child, but holding you child’s hand is encouraged. Talk to your child’s nurse about other ways you can help, such as applying cream to your child’s skin or moistening his or her lips.

Can I still breastfeed if my baby is on ECMO?

If you are breastfeeding, you are strongly encouraged to pump your breasts and store the milk for your baby to use later, when off ECMO. For your convenience, you can use a lactation room that is fully equipped with an electric breast pump. A lactation specialist is on-site to assist you.

ECMO procedure

The ECMO machine has many connecting pieces and moving parts. It consists primarily of a pump and a circuit made up of a membrane (artificial lung), a blood warmer and a filter. The machine removes blue blood (without oxygen), from your child and pumps it through the membrane where it receives oxygen and becomes red. The blood is warmed, filtered and returned to your child. ECMO is used in two different ways depending on your child’s needs:

Veno-arterial (VA) ECMO is used to support both heart and lung function. Blood is drained from a vein and returned to an artery which transports the oxygenated blood to organs and other body tissues where it is needed.

Veno-venous (VV) ECMO is used to support lung function. Blood is drained from the vein, oxygenated and then returned to the vein, where it is pumped through the heart to arteries that carry the oxygenated blood to organs and other body tissues.
ECMO support is established by the surgical placement of large IV-like catheters, known as cannulae, into veins and arteries. A team of surgeons inserts the cannulae, while a specially trained respiratory therapist prepares the ECMO circuit. Another team of ICU physicians and nurses closely monitors your child during the procedure and makes sure that your child remains stable and comfortable. Once the cannulae are inserted and secured, the ECMO circuit is connected to the cannulae and the pump is started.

The ICU team monitors your child while the ECMO specialist monitors the function of the ECMO pump and circuit. Your child will be put on general anesthesia before he or she is placed on ECMO. Since ECMO is used in very serious cases, children are usually already sedated, and additional analgesic agents are administered to augment the sedation. These agents are continued to keep patients asleep until they are weaned off of ECMO.

Where will the cannulae be inserted?

Where the cannulae are inserted can vary depending on age and circumstance. For instance:

  • Infants that require ECMO support for respiratory failure typically have the cannulae inserted through arteries and veins located in the neck area.
  • Older children have the cannulae placed in veins and arteries located in the groin. Patients that require ECMO support following cardiac surgery will typically have their cannulae placed through the surgical incision located in the center of the chest.

 

ECMO risks

Your healthcare team looking after patients on ECMO aim to avoid any complications that may occur from being on the machine. Some of the more serious problems that may occur when a patient is on ECMO include:

Bleeding

Because of the blood thinning medication that patients need while on ECMO, they can start bleeding in different parts of their body. This can be a very serious problem if the bleeding happens in their brain, lungs, insertion sites of cannulae or from their stomach. The healthcare team monitors patients very carefully by frequent physical exams and lab tests to make sure there is no bleeding. If there is bleeding, then medications can be given to help the blood to clot. Sometimes, surgery is needed to stop the bleeding. Blood and other blood products (such as platelets) may also need to be given if blood counts drop too low.

Kidney Failure

Patients who are on ECMO sometimes do not get enough blood flow to their kidneys. This can cause their kidneys to stop working, known as “acute renal failure”. If the kidneys stop working, then a patient may need to be connected to a machine that does the work of the kidneys. This is called dialysis. The kidney damage may get better. However, in some cases, patients may need dialysis for the rest of their life.

Infection

The tubes from the ECMO machine go from outside the patient’s body directly into their bloodstream. This increases the risk for infection, because the tubes are a way for germs to enter the body. The infection can reach the lungs, or any other part of the body. Infections in patients on ECMO can usually be treated with antibiotics. However, some patients who develop infections while on ECMO can get sicker and suffer organ damage.

Leg Damage

Some patients are connected to the ECMO machine through a vein or artery in their thigh. In some cases, this can impair the blood flow down that leg, and the tissue in the leg can die. If this happens, doctors will try to get blood flowing back down the leg. This usually means changing the ECMO tubing to another part of the body. Unfortunately, the damage can occasionally be bad enough that the patient needs surgery to correct the problem, which may include amputation (removal of part of the leg).

Stroke

In patients 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 parts of the brain may be permanently damaged. The area of the brain that is damaged will determine what problems a person has from a stroke. Some patients may not be able to move certain parts of their body, see, remember, speak, read or write. Sometimes a person will recover some function after a stroke, but that is not always the case. Fortunately, strokes are very rare and happen less than 5% of the time to patients on ECMO.

ECMO machine survival rates

In a study involving a total of 265 adult patients who required ECMO support, 130 patients were placed on ECMO between June 2009-December 2013 and 135 patients between January 2014-December 2016. Survival to discharge for patients between 2009-2013 was 37.7% compared to a survival to discharge of 51.9% between 2014-2016 1). According to the researchers, the survival rates difference could be due to a change from individual medical care approach to “ECMO Team” approach which provided a more collaborative approach, which suggested the value of ECMO team based care for ECMO patients.

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