Early Improvement of Acute Respiratory Distress Syndrome in Patients with COVID-19: Insights from the Data of ICU Patients in Chongqing, China.

BACKGROUND: Since the start of the pandemic of coronavirus disease 2019 (COVID-19), over 2 million people has died globally. Acute respiratory distress syndrome (ARDS) may be the main cause of death. OBJECTIVE: This study aimed to describe the clinical features, outcomes, and acute respiratory distress syndrome (ARDS) characteristics of patients with COVID-19 admitted to the intensive care unit (ICU) in Chongqing, China. METHODS: The epidemiology of COVID-19 from January 21, 2020 to March 15, 2020 in Chongqing, China, was analyzed retrospectively, and 75 ICU patients from 2 hospitals were included in this study. On day 1, 56 patients with ARDS were selected for subgroup analysis, and a modified Poisson regression was performed to identify predictors for early improvement of ARDS (eiARDS). RESULTS: Chongqing reported a 5.3% case fatality rate of the 75 ICU patients. The median age of the ICU patients was 57 years (interquartile range, 25-75), and no bias was obtained in the sex ratio. A total of 93% of patients developed ARDS during ICU stay, and more than half had moderate ARDS. However, most of the patients (55%) were supported with high-flow nasal cannula oxygen therapy, but not mechanical ventilation. Nearly one third of patients with ARDS improved (arterial blood oxygen partial pressure/oxygen concentration >300 mm Hg) in 1 week, which was defined as early improvement of ARDS-- eiARDS. Patients with eiARDS had a higher survival rate and lower length of ICU stay than those with "non-eiARDS". Age (<55 years) was the only variable independently associated with eiARDS, with a risk ratio of 2.67 (95% confidence interval: 1.17-6.08). CONCLUSIONS: A new subphenotype of ARDS-- eiARDS in patients with COVID-19 was identified. As clinical outcomes differ, stratified management of patients based on eiARDS or age is highly recommended.