We aim to prospectively assess the burden, management and therapeutic approaches and outcomes of acute respiratory failure requiring respiratory support, during the winter months in China. The purpose of this study is to provide new and current data on the disease burden of acute respiratory failure and ARDS. It will answer the following questions: * The frequency and disease burden of acute respiratory failure in China; * The incidence of ARDS based on the new global definition within this patient cohort. * The mortality of ARDS within this cohort, and how does this vary based on ARDS categories and severity. * The long-term outcomes (1-year mortality and survivor quality of life) of ARDS within this cohort. * The nature course of ARDS (different stages and severity of ARDS). * The respiratory support management strategies, such as recruitment maneuvers, prone positioning, ECCO2R, and ECMO. * The use of drugs during ICU stays, including glucocorticoid, anticoagulant, nitric oxide, sivelestat, Xuebijing, and ulinastatin. * The economical burden of acute respiratory failure within this patient cohort. * The impact of occupation, incomes and education levels on the incidence and mortality of ARDS.