Table 2 Pulmonary pathological features from autopsy cases of COVID-19 ARDS (patient no 1–8), non-COVID-19 ARDS (10–15, 17–19) and non-COVID-19 non-ARDS (9, 16, 19)

1

4

4

4

3

2

Proliferative phase of diffuse alveolar damage, thrombi/microthrombi

2

3

3

4

3

3

Emphysematous change, microthrombi, alveolar septal thickening, thrombi/microthrombi

3

4

4

4

3

3

Pulmonary edema, alveolar septal thickening

4

4

4

4

4

3

Proliferative phase of diffuse alveolar damage, pulmonary hemorrhage, thrombi/microthrombi

5

4

4

4

3

3

Diffuse alveolar damage, Advanced proliferative phase, thrombi/microthrombi

6

4

4

4

4

3

Advanced proliferative phase, pulmonary hemorrhage, thrombi/microthrombi

7

4

4

4

4

3

Exudative phase diffuse alveolar damage, hemorrhage, thrombi/microthrombi

8

4

4

4

4

3

Advanced proliferative phase, hemorrhage, thrombi/microthrombi

9

2

3

2

2

1

Edema

10

3

3

4

3

1

Diffuse alveolar damage, hemorrhage in some regions

11

4

4

4

1

1

Edema, hemorrhage, microthrombi, features of fibroblastic phase

12

4

4

4

3

2

Edema, exudates in lung parenchyma, fibrotic regions, interstitial inflammation and microthrombi

13

4

4

4

4

1

Diffuse alveolar damage

Pulmonary edema, alveolar septal thickening

14

4

4

4

3

1

Epithelial cell denudation, alveolar collapse

15

4

4

4

2

2

Edema, exudates in lung parenchyma, hemorrhage, thrombi/microthrombi

16

1

1

1

1

1

Minor edema in some alveoli

17

3

2

2

3

2

Fibroblast proliferation, microthrombi

18

4

4

4

4

2

interstitial and intra-alveolar fibroblast proliferation, microthrombi

19

2

2

2

1

1

Edema