New theory is coming up for lung involvement in COVID 19. Based on observations in USA, Spain, Italy.
Most of the postmortem revealed pulmonary thorombosis not typical ARDS...... also patient hypoxemia not responding to PEEP but high Fio2 .
Like methemoglobin, the virus structural protein, sticks to heme - displaces oxygen - displaces iron - free iron toxicity causes inflammation of alveolar macrophages- leads to CT scan changes. No benefit of invasive ventilation . May require frequent blood transfusions.
The virus attacks beta chain, dissociates heme, removing iron & converting it to porphyrin.
Virus can dissociate oxy-Hb, carboxy-Hb and glycocilated Hb.
Lung inflammation from inability of both oxygen & CO2 exchange & ground glass x rays, like CO2 poisoning.
Chloroquine competes the binding to porphyrin.
Favipiravir binds to the virus envelope protein with very high affinity, prevents entry into the cells as well as binding of structural protein to porphyrin.
I have received above mentioned theoretical matter on internet.....
More and more research work is to be done to confirm it.....
Please check the link below.
https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30165-X/fulltext