Table 2.

Lung Events and Ayurveda. Importantly COVID-19 lung pathology is more restrictive than obstructive as it is more an alveolar diseases than airway disease, the basic lung pathology classification. Pathological events in lungs and Ayurveda Perspectives are summarized in this table

Lung pathology	Ayurveda pathophysiological interpretations
Diffuse Alveolar Lung Damage: Type II pneumocytes hyperplasia Diffuse alveolar damage with presence of multinucleated pneumocytes. Fibro-granulation tissue proliferation in small airways and airspaces (organizing pneumonia-like lesions) in subpleural locations in some patients [23]. Some studies report along with classical DAD, there are evidences of: Capillary injury Mural and luminal fibrin deposition Infusion of the inter-alveolar septa by Neutrophils/macrophages.	Embryologically lungs are made of bubbling in Rakta (blood) Dhatu. The airsacs represent bubbles, whereas the alveolar composite structure is made from Rakta. COVID-19 is Alveolar disease and thus ‘Rakta Dhatu’ remains pivotal in pathology. Type II pneumocytes which serve as precursor for Type I pneumocytes and those produce surfactants get affected. This Regenerative ability of cells/tissue is attributed to Rasa & Shukra Dhatu the first and last tissue in hierarchy of body tissues. Ayurvedic Rasayana & Vajikarana medicines have regenerative efficacies.
Hyaline membrane formation: A membrane composed of proteins and dead cells lines the alveoli, making gas exchange difficult or impossible, Alveolar condensation	The word exudate is derived from latin “exsudare”, literally meaning ‘to sweat out’. Exudative inflammation is like Vishyandana,Ayurvedic term indicating phenomenon of liquefaction. This further result in alveolar condensation. The hyaline membrane formation and obstruction is nothing but Avarodha (Obstruction) by Kapha in turn leading to further vitiation of Vata.
	Only Kapha is not necessarily responsible for obstructive phenomena. Even Vata subtypes may obstruct each other. COVID-19 symptoms like anosmia, ageusia and impaired Bala (immunity) are seen as symptoms of ‘Prana Avruta Vyana’ [24]. ‘Prana Avruta Vyana’ is condition when Prana Vata (Vata subtype responsible for pulmonary and nervous and cognitive functions) obstructs Vyana Vata (Vata subtype for cardio-pulmonary pumping and Bala i.e. strength and immunity)
Interstitial widening and patches of Lung fibrosis	This can be Upadrava (complication) or Udarka (residual effect) Khara Paka i.e. abnormal metabolism leads to hardening of tissues/fibrotic changes. It will be interesting to see if these post COVID-19 fibrotic changes are therapeutically reversible or not. They can be called as upadrava (Complications) or Udarka (residual effect of the disease that is not relieved by the specific treatment) of COVID-19