I am not a doctor but I have read quite a bit on how COVID-19 affects the body. The ability of a critically afflicted patient to efficiently exchange oxygen drops off a cliff as the lungs fill with a slimy fluid that clogs the alveoli, as the body tries to combat the viral cell damage.

Even with ventilator assisted breathing, their blood-oxygen saturation can go down to 50% or less, which then causes permanent injury or complete failure of the kidneys and other organs due to prolonged oxygen starvation.

A ventilator does not do much to help when the lungs are full of fluid, and seems to be the wrong technology when the lungs are not working properly anyway.


Apparently we should really be using artificial lung technology, which Wikipedia tells me is called Extra-Corporeal Membrane Oxygenation (ECMO), and is less complex than a heart-lung machine as it is assistive to the working heart of the patient.

But I never hear anything in the news about this being used for COVID-19. All the focus has been on ventilators. So why isn't it being widely used and why isn't it being widely discussed?

I expect that the main problem is that it is an even more rare, expensive, and hard to obtain technology than a ventilator. The ratio of artificial lung machines to ventilators is probably 1:100 or even 1:1000.

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    Do you have any evidence it isn't being used besides not hearing about it in the news? Half the time the news can't keep straight the difference between a respirator and a ventilator anyways.
    – Bryan Krause
    Commented Oct 6, 2020 at 20:42
  • I can only turn your question around and ask, do you have any evidence that it is being widely used? A device that hooks into your arteries is rather different looking than machine with a large air tube shoved down your throat. Commented Oct 6, 2020 at 20:59
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2 Answers 2


Why aren't lung machines / ECMO widely used for COVID-19?

They are being used University of Michigan and News Medical

Beyond that, you have already suggested the "why" not being used more widely, there are far fewer ECMO devices than ventilators.

The remark about insurance companies is an inappropriate speculation.


As others have mentioned ECMO is used for covid-19 patients in some locations. I think this information is readily available by searching.

But I will try to provide some more information about why ECMO is not a first choice. Firstly ECMO is a step up from ventilation. Just as ventilation is a step up from providing non invasive positive airway pressure which is a step up from providing supplementary oxygen. As you progress up this pyramid the degree of resources decreases. There are less ventilators than there are e.g. NIV machines. Likewise there are less ECMO devices than there are ventilators. In fact depending on where you live most hospitals will not even have one.

ECMO is not an alternative treatment to ventilation but a treatment to be relied on if ventilation fails. Why? Because it is associated with its own harms:

it remains invasive and associated with significant complications, including tamponade, infection, thrombosis, gas embolism and bleeding. The most dreaded complication is intracranial hemorrhage (ICH)

The risk of intracranial haemorrhage is significant:

The incidence of ECMO-associated ICH varied between 1.8 and 21 %. Mortality rates in ICH-cohorts varied between 32 and 100 %, with a relative risk of mortality of 1.27–4.43 compared to non-ICH cohorts.

These complications can be devastating in patients already severely ill from covid and deconditioned due to ICU stay.

A ventilator does not do much to help when the lungs are full of fluid

This is not necessarily true. Providing positive pressure to the lungs can improve gas exchange even when there is fluid in the alveoli. This is seen in the use of CPAP for cardiogenic pulmonary oedema. This not the same as covid but meant to illustrate that fluid in the lung doesn't render the lung useless for gas exchange. Covid pneumonia and ARDS are different situations but I wanted to point out this is not a correct assumption.

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