(This may belong in GQ. Please move if needed.)
I was thinking today about the question of how to get more oxygen into patients with breathing problems due to CoVID-19. I started wondering if using a cardiac bypass machine might be a way to oxygenate blood. I don’t think that there’s anywhere near enough of those machines, even if it were feasible.
Then I started thinking about other machines that circulate blood. Could a dialysis machine be used to oxygenate blood?
ExtraCorporeal Membrane Oxygenation (ECMO) is the process. Typically it is only used in the short term such as during open heart surgery, but there have been recent reports of patients being placed on ECMO for up to a couple weeks or more.
ECMO is different to a heart lung machine. But is indeed the final chance for some COVID-19 patients. The Japanese reported that 50% recovered on ECMO. But it is a truely brutal and invasive technique and not really intended for multiple weeks of use. Patients need serious anticoagulant therapy and this alone can lead to bad outcomes. There are not all that many machines about. Large hospitals may have a few.
Right - that’s why I was wondering if a dialysis machine could be modified to add more Oxygen to the blood, since it also circulates blood.
Not in enough quantities. A dialysis machine circulates relatively low volumes of blood. An ECMO is circulating blood at 10 to 20 times the rate. Which is why it is so brutal. You can’t get that sort of blood flow with a cannula in the arm. You need access via major arteries.
I posed this question a few days ago to my daughter, who runs ECMO. She says it is a last-resort treatment, and particularly for COVID patients, they rarely are put on it (in her experience) because their chance of survival is so low. To put it another way, most COVID patients that make it to her unit have multiple failing organs or other complications, and ECMO really would just keep them alive two days longer.
A lot of sad.
I never worked in a place that did ECMO, but from what I’ve heard, it’s most useful in critically ill children. Adults who are put on it usually die anyway, if it doesn’t kill them outright, and the ones who recover usually have lifelong health issues, from just plain old being sick enough to need it.
It also costs about $100,000 a day, just for the ECMO, FYI.
I’ll dispute 100K/day, my son was on one for 18 days in 2013 and the bill to the insurance company was well under that figure, even considering the 60 days he was hospitalized.
On the other hand, at the ripe old age of 17, many were very concerned that ECMO was not a great choice for him. We have a great Primary Care doctor (a few of the PICU team coincidently had him as their doctor) who is still amazed how well it worked out. His typical comment was that “I’ve worked with a few older patients on ECMO, did not work out well.” This may not be true for everyone but several of the care staff indicated that older people do not respond well.
I could go on about all the scary things that happened during those 18 days, it’s not something you want to happen to you.
On a side note, I was in the room the first night where, after surgery to insert the tubes, they were setting up the machine. The doctor was working the settings like he was playing a finely tuned piano, I’m impressed and thankful to this day. The machine was attended 24 hours/day and people frequently cycled through to remain current on ECMO support.
Does Total Corporeal Perfusion still exist as a treatment for liver toxicity overload? The term extracorporeal above prompted me to ask. I remember being a medic in the AF many years ago, and it was a military doctor, IIRC, who came up with the technique. Would this be of any use to Covid-19 sufferers? The COMPLETE exchange of blood would seem to provide a sudden rush of oxygen that might buy the patient extra time to deal with the disease?
Not really. The sudden rush would last less than a minute. Think about how long a person can survive drowning.
The ECMO systems pump the entire blood content of the subject through the membrane in less than a minute. (One of the reasons they require 24x7 dedicated supervision. A simple leak can quickly pump the patient’s entire blood volume out of their body.) So they effectively get complete exchanges that fast.
Can’t find the article again to link to.
A doctor who was experienced in treating patients with oxygen deprivation said that the organ damage caused by serious Covid19 episodes does resemble what he has commonly seen. He recommended O2 treatment but the article did not go into what that entailed.