Abstract: Objective To investigate the effect of sivelestat sodium on survival, oxygenation index, and serum markers for infection in critically ill patients with COVID-19-associated acute respiratory distress syndrome (ARDS). Methods This retrospectively study was performed among the critically ill patients with COVID-19-associated ARDS admitted in the intensive care unit (ICU) at Nanfang Hospital, Southern Medical University. We collected the clinical data of the patients on the first day of ICU admission and on the day of discharge and laboratory tests results of interleukin-6 (IL-6), C-reactive protein (CRP) and procalcitonin (PCT) and oxygenation index on days 1, 3 and 7 following ICU admission. Propensity-score matching was used to match the patients receiving sivelestat sodium to those without the treatment. Cox proportional hazards model and linear regression analysis were used to assess the association of sivelestat sodium treatment with in-hospital mortality and the length of hospital stay. Results A total of 199 patients with COVID-19- associated ARDS patients were included for data analysis. After propensity-score matching PSM, 35 patients receiving sivelestat sodium were matched to 70 patients without the treatment. Treatment with of sivelestat sodium was not associated with the reduction of in- hospital mortality (P=0.36), prolonged ICU stay (P=0.39), hospital stay (P=0.68) or improved oxygenation index (P>0.05) of the patients. No significant difference was found in serum CRP or PCT levels between the patients with and without sivelestat sodium treatment, but a significant reduction in IL-6 level was found in sivelestat sodium group (P=0.016). Conclusion Sivelestat sodium treatment is not correlated with the reduction of mortality or length of hospital stay, but is associated with reduced serum IL- 6 level in patients with COVID-19-associated ARDS.

Key words: sivelestat sodium; acute respiratory distress syndrome; COVID-19; interleukin-6