Quote Originally Posted by Plutonic Panda View Post
Are iron lungs going to come back?
Not really a helpful option here. Iron lungs fix a mechanical issue (muscle paralysis or weakness) and create the pressure differential needed for the lungs to expand and contract inside the chest which then results in air moving in and out of the lungs. The iron lung decreases pressure inside the machine, which causes the chest wall to expand. When the chest wall expands it decreases the pressure inside the chest itself, which causes the lungs to expand. When the lungs expand, it creates low pressure inside the lungs, which causes air to move into the lungs where O2 and CO2 is exchanged with the blood. It’s a fairly “basic” design, and clamshell type external respirators are still used at times to assist people.

Ventilators also work with pressure of course, but instead of manipulating the external pressure to move air in and out of the lungs it directly manipulated the pressure inside the lungs. Instead of air getting sucked into the lungs, it is pumped into the lungs. Ventilators give much more control over all the different aspects of respiration: volume of air being moved, pressure of the air entering the lungs, pressure remaining during exhalation to keep the lungs open or to push fluids out of the lungs. They can also control the exact mixture of air entering the lungs, the temperature, the humidity, etc. From the basic CPAP people have on their night stand to the complex machines at hospitals, there are a ton of options for ventilators out there. But in the end, the ventilators have the same limitations that the iron lungs have: they can get air in and out of the lungs, but the lungs themselves have to do the work of gas exchange to get oxygen in, and CO2 out.

The issue with people at these stages of COVID is that the lungs are so damaged, and the lung tissue itself is so damaged, that the gas exchange just doesn’t happen. You can pump all the pure oxygen you want into those lungs, but it will never cross through those tissues and get into the blood. And none of the CO2 is ever going to cross through those tissues and leave the body. Ventilators, iron lungs, they all just inflate and deflate two useless bags of tissue at that point.

That’s where ECMO (extracorporeal membrane oxygenation, artificial lungs) comes in. Instead of trying to get air into your lungs to get oxygen into your blood, it bypasses your lungs and heart and takes the blood out of your body, runs it through the machine to take CO2 out and put O2 in, and then pump it back into and through your body. And then they just wait and hope that at some point your lungs will heal enough that they can put you back on a regular vent and maybe send you back home on oxygen for the rest of your life. Or they wait until a lung transplant becomes available. But while that machine is running, while it is your heart and lungs, you are alive and could sit there and talk with your family and play games, watch TV, etc, for as long as you’re connected to the machine and it keeps on working.

Instead of being brain dead, with a machine keeping you alive, you are basically “lung dead”, with a machine keeping you alive. It’s still quite some steps away, but it does get us a step closer to the ethical question of “if a body is so damaged that it can’t survive, but you could cut off the head and connect it to this machine, is it ethical to keep your head and brain alive that way”.