There is no 'pneumonia' nor ARDS. At least not the ARDS with established treatment protocols and procedures we're familiar with. Ventilators are not only the wrong solution, but high pressure intubation can actually wind up causing more damage than without, not to mention complications from tracheal scarring and ulcers given the duration of intubation often required... They may still have a use in the immediate future for patients too far to bring back with this newfound knowledge, but moving forward a new treatment protocol needs to be established so we stop treating patients for the wrong disease.
The past 48 hours or so have seen a huge revelation: COVID-19 causes prolonged and progressive hypoxia (starving your body of oxygen) by binding to the heme groups in hemoglobin in your red blood cells. People are simply desaturating (losing o2 in their blood), and that's what eventually leads to organ failures that kill them, not any form of ARDS or pneumonia. All the damage to the lungs you see in CT scans are from the release of oxidative iron from the hemes, this overwhelms the natural defenses against pulmonary oxidative stress and causes that nice, always-bilateral ground glass opacity in the lungs. Patients returning for re-hospitalization days or weeks after recovery suffering from apparent delayed post-hypoxic leukoencephalopathy strengthen the notion COVID-19 patients are suffering from hypoxia despite no signs of respiratory 'tire out' or fatigue.Here's the breakdown of the whole process, including some ELI5-level cliff notes. Much has been simplified just to keep it digestible and layman-friendly.
Your red blood cells carry oxygen from your lungs to all your organs and the rest of your body. Red blood cells can do this thanks to hemoglobin, which is a protein consisting of four "hemes". Hemes have a special kind of iron ion, which is normally quite toxic in its free form, locked away in its center with a porphyrin acting as it's 'container'. In this way, the iron ion can be 'caged' and carried around safely by the hemoglobin, but used to bind to oxygen when it gets to your lungs.
When the red blood cell gets to the alveoli, or the little sacs in your lungs where all the gas exchange happens, that special little iron ion can flip between FE2+ and FE3+ states with electron exchange and bond to some oxygen, then it goes off on its little merry way to deliver o2 elsewhere.
Here's where COVID-19 comes in. Its glycoproteins bond to the heme, and in doing so that special and toxic oxidative iron ion is "disassociated" (released). It's basically let out of the cage and now freely roaming around on its own. This is bad for two reasons:
1) Without the iron ion, hemoglobin can no longer bind to oxygen. Once all the hemoglobin is impaired, the red blood cell is essentially turned into a Freightliner truck cab with no trailer and no ability to store its cargo.. it is useless and just running around with COVID-19 virus attached to its porphyrin. All these useless trucks running around not delivering oxygen is what starts to lead to desaturation, or watching the patient's spo2 levels drop. It is INCORRECT to assume traditional ARDS and in doing so, you're treating the WRONG DISEASE. Think of it a lot like carbon monoxide poisoning, in which CO is bound to the hemoglobin, making it unable to carry oxygen. In those cases, ventilators aren't treating the root cause; the patient's lungs aren't 'tiring out', they're pumping just fine. The red blood cells just can't carry o2, end of story. Only in this case, unlike CO poisoning in which eventually the CO can break off, the affected hemoglobin is permanently stripped of its ability to carry o2 because it has lost its iron ion. The body compensates for this lack of o2 carrying capacity and deliveries by having your kidneys release hormones like erythropoietin, which tell your bone marrow factories to ramp up production on new red blood cells with freshly made and fully functioning hemoglobin. This is the reason you find elevated hemoglobin and decreased blood oxygen saturation as one of the 3 primary indicators of whether the shit is about to hit the fan for a particular patient or not.
2) That little iron ion, along with millions of its friends released from other hemes, are now floating through your blood freely. As I mentioned before, this type of iron ion is highly reactive and causes oxidative damage. It turns out that this happens to a limited extent naturally in our bodies and we have cleanup & defense mechanisms to keep the balance. The lungs, in particular, have 3 primary defenses to maintain "iron homeostasis", 2 of which are in the alveoli, those little sacs in your lungs we talked about earlier. The first of the two are little macrophages that roam around and scavenge up any free radicals like this oxidative iron. The second is a lining on the walls (called the epithelial surface) which has a thin layer of fluid packed with high levels of antioxidant molecules.. things like abscorbic acid (AKA Vitamin C) among others. Well, this is usually good enough for naturally occurring rogue iron ions but with COVID-19 running rampant your body is now basically like a progressive state letting out all the prisoners out of the prisons... it's just too much iron and it begins to overwhelm your lungs' countermeasures, and thus begins the process of pulmonary oxidative stress. This leads to damage and inflammation, which leads to all that nasty stuff and damage you see in CT scans of COVID-19 patient lungs. Ever noticed how it's always bilateral? (both lungs at the same time) Pneumonia rarely ever does that, but COVID-19 does... EVERY. SINGLE. TIME.
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