Artificial organs

The heart is just a motor, the kidneys are just a filter, the lungs are just a blood oxygenator, and the liver can even regenerate.
This page is written in the special context of potentially combining artificial organs into artificial body. Can it keep brain alive?

Artificial heart + lungs

ECMO A/V
ECMO is like artificial heart + lungs.
"People can stay on ECMO anywhere from days to weeks"[1]
Record of successful being on A/V ECMO seems like at least 37 days (or maybe 87 days).
How much survival depends on how long you have been on ECMO? What complications ECMO has that it's used for only weeks?
ECMO mortality is high (~34% for adults[2]) but perhaps in part due to acute health problems preceding ECMO?
Anyway, ~63% of deaths on AV ECMO were due to multiorgan failure: https://pubmed.ncbi.nlm.nih.gov/23616484/, table 2.
Multiorgan failure happens largely due to sepsis or
A good video is...
Currently, "Most people with end-stage heart failure have a life expectancy of less than 1 year"[3]
Median cost of ECMO in Norway in 2007 was ~$62k, median total hospital cost ~$191k, mean stay on ECMO was 9.5 days https://pubmed.ncbi.nlm.nih.gov/19699650/

ECMO V/V
ECMO V/V is like artificial lungs
Record of successful being on V/V ECMO seems like about >300days or at least 107 days.

Generally about ECMO
"The incidence of acute kidney injury is 70-85% in ECMO patients. Therefore, renal replacement therapy is required in approximately 50% of these patients" However, that can be partly explained by the fact that patietns have factors for AKI even before ECMO: "Prior to the initiation of ECMO, the etiology of AKI in these patients is almost always because of multiple factors such as sepsis, low cardiac output syndrome, exposure to nephrotoxic agents".
ECMO introduces major haemodynamic changes and needs anticoagulation treatment (which might cause bleeding complications). Would we need anticoagulation treatment in head transplantation to artificial body? Btw would it be simpler to have access to major brain arteries to somehow alleviate their probable atherosclerotic processes? (with stents/etc).

About artificial heart (w/o lungs).
Syncardia artificial heart is the only biventricular cardiac replacement approved by FDA[4].

Syncardia artificial hearts were implanted in more than 2000 patients worldwide
(btw, "The TAH-t has been covered by Medicare since 2008")

"After a TAH-t patient becomes clinically stable, they can be switched from the Companion 2 (C2) Hospital Driver to the Freedom Driver, a smaller, lighter pneumatic pump" which weights just ~6.8kg. Though it was approved by FDA in 2014 (and in Canada in 2011), the current experience is just 240 patient-years (as of jan2023).

However, the total number of surgeries with artificial heart implantation seems to decrease rapidly in recent years.
For example, this 2022y paper of Cedar Sinai Medical Center says: "The annual volume increased from 1 case in 2012 to 24 cases in 2014, and subsequently declined thereafter to 1 case in 2022" (p.2); "The utilization of TAH-t at our center has decreased dramatically. That decrease is in large part due to improvements in short-term MCS options such as ECMO and improved outcomes with left ventricular assist device therapy" (p.6).

Artificial kidneys

They exist already, for a long time. "If you have both kidneys completely removed, you will not make any urine. You will need to have kidney dialysis <...> many people manage very well with it. There are 2 different types of kidney dialysis. You can use a kidney dialysis machine at a dialysis centre. Or you can use a permanent tube and bag of fluid at home"[5]
Good visualisation of dialysis: https://www.youtube.com/watch?v=gRoleVEwR8c&t=58s (from 0:58 to 1:52)
See Patients survival on dyalisis; briefly, it's 5-10 years, with cachexia and infections as specific causes of death.

Dialysis rate is "usually between 300 and 500 mL/min"[6].
Compare to total cerebral blood flow which is roughly 700±100 mL/min[7].
Annual dialysis cost (usually with 3 sessions a week for 3-6h each) is roughly $3400 to $43000 depending on country[8] (1998-2013 studies were reviewed; year was different for countries). Anyway it's probably a small part of overall costs for head transplantation.

"Over 2 million people worldwide currently receive treatment with dialysis or a kidney transplant to stay alive, yet this number may only represent 10% of people who actually need treatment to live"[9] so really large interested community, large market etc.

Artificial blood production

https://pubmed.ncbi.nlm.nih.gov/30711308/ reviews possibility of using genetically modified pigs as blood donors for humans.
See also en.wikipedia article. As there is always a shortage of blood for transfusions, this would be funded and overall seems to be quite solvable task.
If red blood cells live ~100days, just one or several pigs could support needed blood for one person (even not in context of head transplantation).

Is it possible to keep the brain alive with a module body with artificial or natural organs?

In paper https://pubmed.ncbi.nlm.nih.gov/23136216/ only 17% of patients on ECMO and with acute kidney injury survived for 3 months.
So even bad functioning (not full failure) of just two systems (lungs, kidneys) is so critical and not manageable with current technologies (though the paper was published in 2013 so maybe situation is better somewhat now).
... on the other hand, in the paper they kept all the body alive. What if we have to keep alive just head? That must have its advantages. Head weight is small (though head cconsumes ~20% energy of body).

To the best of my knowledge, I would argue that there is no combination of devices that could support life for considerable time in the case of multi-organ failure. However, if (1) we need to support just head and not the whole body, (2) we can buy new donor blood from time to time (may be even every day) then perhaps they would success? Needs further analysis.