I saw the same Youtube, but it just makes no sense. I am sure there is necrotic debris in the alveoli of ARDS, however, it is so deep in the lung circuity that if you stood on your head for a year it wouldn’t drain. Secondly, the ideas of proning has to do with physiological oxygenation called the West Zones (the sentinel work in respiratory physiology). Briefly, West Zone I is dead space, It is where there is ventilation but not a lot of blood flow. In the supine human standing up, the gravitation effect on liquid (blood) creates a gradient that the apices of the long have less blood flow than the bases. So — dead space mismatch. West Zone 2 is optimal, it is where ventilation and perfusion are matched. It is the site of most efficient oxygen an CO2 exchange. West Zone 3 are where hydrostatic pressures (liquid weighs more than gas) exec alveolar ventilation. So there is Shunt (blood flowing past collapsed gas spaces). So, proning someone tends to create more West Zone 2 because there is less hydrostatic forces across the entire lung (biophysics suggest that in the spin position there is more dorsal lung surface area than ventral). So, putting the thorax below neutral axis would actually expand west zone 3 and increase shunt physiology — it just doesn’t make sense from a bedside perspective Possible confounding variable.
https://www.hawaiinewsnow.com/2020/03/24/virtual-rendering-coronavirus-patients-lungs-shows-extensive-damage-virus-can-cause/
The damage caused by this virus is *diffuse*. I don't think we have enough data, to have defined if there are any regular patterns in the damage, in a majority or even just a plurality, of the patients.
This leaves open the possibility, that there are compromised alveoli (see the WebMD link, which has language contradicting your assertion of inflammation being the sole cause of inhibited O2/CO2 exchange), throughout each of the West Zones. God only knows, what that would do, to either pressure gradients (no longer a monotonic function of distance along the lung), blood flow (necrotic debris probably doesn't have the same rate of flow through the capillaries as intact tissue), or the ratio of the two...
A second issue, in the YouTube you saw, is it necessarily true that all of the fluids being drained, are necrotic debris rather than surfactant-mixed-with-mucus (I read elsewhere, one of the first spots hit by this virus is the cilia in the bronchial tubes, so that mucus doesn't get swept out of the lungs, thereby somewhat mimicking Cystic Fibrosis)...So if you loosen *that*, it doesn't "run downhill" and further clog up the works, just when you have all the inflammation / necrosis / body-trying-to-clean-up going on. Or, as Calvin and Hobbes might put it:
These are all great questions, but clinically its the risk benefit analysis. I would be hard pressed to give up west zone 2 for 3 in oder to drain.
But anyone who quote Calvin and Hobbes is Ok in my book, even if we disagree...