Table 1. Histopathological scoring criteria of lung.

Score	Hyaline membranes	Microthrombi	Edema	Interstitial infiltration	Atelectasis	Hemorrhage
0	Absent	Absent	Absent	Absent	Absent	Absent
1	Discrete	Few in small vessels	Discrete	Discrete	Small foci	Small foci
2	Moderate	Some	Moderate	Moderate	Larger foci	Larger foci
3	Severe	Many larger vessels	Severe	Severe	Diffuse	Diffuse