关键词: 新型冠状病毒肺炎, 急性呼吸窘迫综合征, 氧合指数, 弥散指数, 机械通气, 呼吸末正压, 预后

Abstract: Backgroud  In the treatment of severe and severe cases，New Coronavirus pneumonia diagnosis and treatment plan （Trial Seventh Edition） suggested that if the patients did not improve or deteriorate within a short time （1-2 h） after the use of high flow nasal catheter oxygen therapy or non-invasive ventilation，tracheal intubation and invasive mechanical ventilation should be carried out in time. No objective reference indexes have been proposed in the opinions，and the commonly used oxygenation index is insufficient in the clinical application of such patients，so it is particularly important to explore more valuable reference indexes. Objective　To compare the difference of dispersion index and oxygenation index in the prognosis assessment of patients diagnosed with Novel Coronavirus Pneumonia （COVID-19） who have acute respiratory distress syndrome （ARDS） when they are treated with mechanical ventilation. Methods　A retrospective single center study was conducted in 39 patients with ARDS of Novel Coronavirus Pneumonia admitted to ICU with mechanical ventilation of Wuhan Tianyou Hospital from January 25，2020 to March 14，2020. Two of them were lost due to death within 24 hours，patients were divided into survival group （n=11） and death group （n=26） according to their 28-day status. Ventilator parameters and corresponding blood gas values were recorded to study the correlation between dispersion index and oxygenation index and 28 days' prognosis of patients. Results　The worst oxygenation index，the dispersion index，and the worst dispersion index when entering ICU in the survival group were higher than those in the death group （P<0.05）. The sensitivity of the oxygenation index to predict death when entering the ICU was 100.0%，the specificity of the oxygenation index was 46.2%，the area under the ROC curve （AUC） was 0.654，and the difference between AUC and the reference value was not statistically significant （P=0.144）；The sensitivity of the oxygenation index to predict death was 3.8%，the specificity was 100.0%，and the AUC was 0.862 when the oxygenation index was the lowest，comparing with the reference value，the difference was statistically significant （P<0.05）；The sensitivity of the dispersion index to predict death was 7.7%，the specificity was 100.0%，and the AUC was 0.734 when entering the ICU，comparing with the reference value，the difference was statistically significant （P<0.05）；The sensitivity of the dispersion index to predict death was 100.0%，the specificity was 80.8%，and the AUC was 0.902 when the dispersion index was the lowest，comparing with the reference value，the difference was statistically significant （P<0.05）. Conclusion　Dispersion index is a more sensitive and reliable prognostic indicator for ARDS in Novel Coronavirus Pneumonia patients than oxygenation index. The dispersion index is a more sensitive and reliable prognostic evaluation index than the oxygenation index in Novel Coronavirus Pneumonia patients with ARDS.

Key words: COVID-19, Acute respiratory distress syndrome, Oxygenation index, Dispersion index, Mechanical ventilation, PEEP , Prognosis