Abstract
INTRODUCTION: Severe COVID-19 is a life-threatening condition characterized by complications such as interstitial pneumonia, hypoxic respiratory failure, and acute respiratory distress syndrome (ARDS). Non-pharmacological intervention with mechanical ventilation plays a key role in treating COVID-19-related ARDS but is influenced by a high risk of failure in more severe patients. Dexmedetomidine is a new generation highly selective α2-adrenergic receptor (α2-AR) agonist that provides sedative effects with preservation of respiratory function. The aim of this study is to assess how dexmedetomidine influences gas exchange during non-invasive ventilation (NIV) and high-flow nasal cannula (HFNC) in moderate to severe ARDS caused by COVID-19 in a non-intensive care setting. METHODS: This is a single center retrospective cohort study. We included patients who showed moderate to severe respiratory distress. All included subjects had indication to NIV and were suitable for a non-intensive setting of care. A total of 170 patients were included, divided in a control group (n = 71) and a treatment group (DEX group, n = 99). RESULTS: A total of 170 patients were hospitalized for moderate to severe ARDS and COVID-19. The median age was 71 years, 29% females. The median Charlson comorbidity index (CCI) was 2.5. Obesity affected 21% of the study population. The median pO(2)/FiO(2) was 82 mmHg before treatment. After treatment, the increase of pO(2)/FiO(2) ratio was clinically and statistically significant in the DEX group compared to the controls (125 mmHg [97-152] versus 94 mmHg [75-122]; ***p < 0.0001). A significative reduction of NIV duration was observed in DEX group (10 [7-16] days vs. 13 [10-17] days; *p < 0.02). Twenty four patients required IMV in control group (n = 71) and 16 patients in DEX group (n = 99) with a reduction of endotracheal intubation of 62% (OR 0.38; **p < 0.008). A higher incidence of sinus bradycardia was observed in the DEX group. CONCLUSION: Dexmedetomidine provides a "calm and arousal" status which allows spontaneous ventilation in awake patients treated with NIV and HFNC. The adjunctive therapy with dexmedetomidine is associated with a higher pO(2)/FiO(2), lower duration of NIV, and a lower risk of NIV failure. A higher incidence of sinus bradycardia needs to be considered.