The effectiveness of dexmedetomidine in patients with severe COVID-19

Background: Mortality in patients with severe COVID-19 remains high. Finding therapies that can improve the outcome in these patients is an urgent task. Aims: To evaluate the clinical efficacy of dexmedetomidine in the complex treatment of patients with a severe course of COVID-19. Methods: The retrospective study included 50 adult patients with severe COVID-19 admitted to the intensive care unit (ICU). The primary outcome of the study was the incidence of delirium. The secondary results of the study were the dynamics of gas exchange indicators (PaO2 and PaCO2) and inflammatory markers (C-reactive protein, CRP; procalcitonin, lymphocyte count, and neutrophil-lymphocyte ratio, NLR) on day 3 and day 5 of the treatment, as well as the duration of mechanical ventilation (MV), length of stay (LOS) in the ICU and in the hospital and mortality. Results: The incidence of delirium did not differ between the dexmedetomidine group and the control group (41 and 48%, respectively; p=0.661). The LOS in the ICU and in the hospital, as well as the MV duration, was comparable between the groups. However, the hospital mortality in the dexmedetomidine treatment group was lower than that in the control group (10.3% and 42.9%, respectively; p=0.008). The addition of dexmedetomidine to the therapy complex did not affect the blood gas composition but contributed to the increase in the number of lymphocytes (p=0.006) and to the NLS decrease (p=0.002) by the fifth day of treatment. At the same time, no significant changes in the CRP and procalcitonin levels were observed. Conclusion: In the treatment group, the mortality was statistically significantly lower than it was in the control group. At the same time, the use of dexmedetomidine did not reduce the incidence of delirium, the length of stay in the ICU and in the hospital, and the duration of mechanical ventilation in patients with severe COVID-19. The revealed relationship between the use of dexmedetomidine and NLR and the number of lymphocytes suggests an immune-mediated effect on the outcome in this category of patients. Prospective randomized trials are needed to confirm the beneficial effects of dexmedetomidine on the immune system and mortality.