Impact of a Non-Invasive Respiratory Support Strategy and Switches in Therapy During Acute Respiratory Failure Due to SARS-COV-2

Introduction: Non-invasive respiratory support (NIRS), high flow nasal cannula (HFNC) and non-invasive ventilation (NIV), have been used prior to mechanical ventilation (MV).We aimed to describe the use of initial NIRS and their subsequent changes and assess its impact on clinical outcomes among critically ill patients with acute respiratory failure (ARF) secondary to SARS-CoV-2 admitted to ICU.Methods: Prospective, multicenter, observational cohort study comprising a secondary analysis of patients included in the SEMICYUC COVID-19 registry.All patients with ARF due to SARS-CoV-2 admitted to ICU and receiving respiratory support were enrolled.NIRS failure, ICU and hospital mortality, and length of stay (LOS) were evaluated.Results: Among 3889 included patients, 43% initially underwent NIRS (75% HFNC and 25% NIV).NIV as first choice was associated with higher failure (74.4% vs 61.2%, p<0.001) and higher ICU and hospital mortality rates than HFNC (27% vs 20%, p=0.003 and 29% vs 21%, p=0.002).NIV to HFNC switch showed the lowest failure (43%), lowest ICU and hospital mortality rates (18% and 19%) and the shortest LOS (9 days [6-15] vs 21 days [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]).HFNC to NIV switch did not significantly worsen outcomes compared to HFNC failure, but patients who failed after the switch showed the highest mortality (42% both ICU and hospital) and the longest LOS (24 [13-34] and 30 [23-48]).Conclusion: NIRS is common in the ICU and switching NIRS strategies is a frequent practice within different scenarios.Physicians should bear in mind the possibility of outcomes worsening when failure occurs after switching.