ECMO therapy: lifesaver in severe COVID infection?

Patients with severe lung diseases up to and including acute lung failure often have to be artificially ventilated. In some cases, the lungs themselves are no longer able to release the supplied oxygen into the blood in sufficient quantities. The blood is then oxygenated outside the body. This process is colloquially referred to as an artificial lung.

The artificial lung or extracorporeal membrane oxygenation (ECMO) is also used in severe cases of COVID-19 with lung failure. This is how the ECMO works and this is something to consider.

ECMO: This is how the artificial lung works

The ECMO is a modified heart-lung machine with a closed system. The venous blood is drawn out of the patient’s body via a cannula, enriched with oxygen, then heated and fed back through the cannula into the venous or arterial system of the patient.

Up to five liters of blood can be transported in an adult within one minute, the gas exchange takes place on an artificial membrane.

In summary, the artificial lung performs the following functions:

• Release of carbon dioxide from the blood
• supply of oxygen
• Regulation of blood temperature

The ECMO can also be used to provide medical care to the patient. Drugs  and substances such as  heparin  to prevent blood clotting are also administered as part of the gas exchange.

In emergencies, the artificial lung can stabilize the body for several days to weeks and relieve the lungs. In general, ECMO is gentler on the lungs than the well-known artificial respiration.

There are also two different types of artificial lungs: while veno-venous ECMO alone supports the function of the lungs, veno-arterial ECMO is used in the case of a damaged heart including a damaged lung.

COVID-19 and other lung diseases: areas of application for the artificial lung

ECMO therapy is currently mostly used in the context of a severe corona infection and the resulting respiratory insufficiency. In medicine, the ECMO is also used in other areas:

• Bridging until recovery, after severe  pneumonia
• Artificial care up to successful therapy for pulmonary embolism or acute cardiopulmonary failure
• Bridging the lung function in the case of artificial heart implantations or planned lung transplants

Since lung failure is a common consequence of a corona infection, physicians are looking at ECMO as a treatment option for severe COVID-19.

ECMO as the last treatment option for a corona infection

Die Erfolgsaussichten der ECMO bei einer schweren Corona-Infektion waren zu Beginn gering. Nach ausreichenden Erfahrungsberichten und ausgereiften Behandlungsabläufen zeigt sich die künstliche Lunge mittlerweile dennoch als geeignete Therapiemöglichkeit.

Auf Basis erster Studien schlägt die ECMO-Therapie besonders bei jüngeren Patient*innen im Alter bis 48 Jahren an. Die Behandlung sollte allerdings in einem frühen Stadium erfolgen, um besonders wirksam zu sein. Insgesamt weisen die Daten auf eine erhöhte Überlebensrate von 30 bis 55 Prozent hin.

Allerdings ist bei COVID-Patient*innen höchste Vorsicht geboten. Besonders Corona-Erkrankte zeigen häufiger Komplikationen als ECMO-Patient*innen, die nicht an einer COVID-Infektion leiden. Häufige Probleme sind:

• Hirnblutungen (12 Prozent)
• Pneumonia as a result of ventilation (85 percent)
• pulmonary embolism (18 percent)

In total, only around 800 ECMO places are available in Germany. The method requires specially trained personnel who know how to deal with the risks and technical challenges of ECMO.

Therefore, the ECMO is only used in special exceptional cases:

• If the patient does not respond to other ventilation strategies.
• If there is a possibility of regeneration of the lungs.
• In younger patients, since the risk of complications is too high in older people.

ECMO represents an opportunity if the sick person no longer responds to alternative treatment options, but the artificial lung does not offer a guarantee of survival.