摘要
To the Editor:The randomized evaluation of coronavirus 2019(COVID-19)therapy(RECOVERY)[1]clinical trial showed that glucocorticoids can affect the prognosis of severe COVID-19 patients,but they have no benefit for mild disease.Other clinical trials,such as COVID-19-associated acute respiratory distress syndrome(ARDS)treated with dexamethasone(CoDEX)and efficacy study of dexamethasone to treat the ARDS(DEXA-ARDS),have also proven the effectiveness of glucocorticoids.On the basis of these trials,glucocorticoids have been recommended for the treatment of COVID-19,although their mechanism of action is unclear.Diffuse alveolar damage(DAD)is not the only pathological change of ARDS caused by COVID-19.In some cases,organizing pneumonia(OP)or acute fibrinous and organizing pneumonia(AFOP)is the main manifestation.[2]Acute patterns of AFOP with AFOP as the main pathological feature often leads to respiratory failure and rapidly progresses to death,whereas subacute patterns of AFOP has a good prognosis.There are two types of COVID-19-related ARDS:type 1 is atypical ARDS,with low elasticity(type L),increased compliance,and imbalance of ventilation/perfusion ratio;and type 2 is classic ARDS,with high elasticity(type H),reduced compliance,and increased right to left diversion,which is mainly related to disease progression(but not absolutely).
