重型与危重型新型冠状病毒肺炎患者多表现为呼吸困难和/或难治性低氧血症，呼吸支持技术是最基本和最重要的治疗手段。不同呼吸支持策略应用时机的把握及病情恶化的早期预测是临床救治中的难点，直接关系到治疗的成败。因此，了解病情转归的危险因素，掌握不同呼吸支持策略的应用指征，个体化评估疗效，将有助于提高新型冠状病毒肺炎的临床救治率，降低重症患者的病死率。“,”Severe and critical COVID-19 patients are characterized by dyspnea and/or refractory hypoxemia.Respiratory support technology is the most basic and important treatment for severe patients.It is difficult to grasp the timing of different respiratory support strategies and to predict the early deterioration of the disease, which is directly related to the results of treatment.Therefore, we need to understand the risk factors of disease progression, and grasp the application indicators of different respiratory support strategies, and evaluate the efficacy individually.It will help us to improve the clinical cure rate of COVID-19 and reduce the mortality of severe patients.