# Prognosis of mechanically ventilated patients with COVID-19 after failure of high-flow nasal cannula: a retrospective cohort study

## TL;DR

This study found that using high-flow nasal cannula before mechanical ventilation in COVID-19 patients did not worsen their respiratory outcomes.

## Contribution

The study provides evidence that HFNC failure before mechanical ventilation does not lead to worse respiratory outcomes in COVID-19 patients.

## Key findings

- HFNC failure before mechanical ventilation was not linked to worse respiratory failure in COVID-19 patients.
- The HFNC-F group had a lower rate of ECMO use at 28 days compared to the MV group.
- Dynamic compliance on day 3 was slightly higher in the MV group, but differences were minimal.

## Abstract

There is an argument whether the delayed intubation aggravate the respiratory failure in Acute respiratory distress syndrome (ARDS) patients with coronavirus disease 2019 (COVID-19). We aimed to investigate the effect of high-flow nasal cannula (HFNC) failure before mechanical ventilation on clinical outcomes in mechanically ventilated patients with COVID-19.

This retrospective cohort study included mechanically ventilated patients who were diagnosed with COVID-19 and admitted to the intensive care unit (ICU) between February 2020 and December 2021 at Asan Medical Center. The patients were divided into HFNC failure (HFNC-F) and mechanical ventilation (MV) groups according to the use of HFNC before MV. The primary outcome of this study was to compare the worst values of ventilator parameters from day 1 to day 3 after mechanical ventilation between the two groups.

Overall, 158 mechanically ventilated patients with COVID-19 were included in this study: 107 patients (67.7%) in the HFNC-F group and 51 (32.3%) in the MV group. The two groups had similar profiles of ventilator parameter from day 1 to day 3 after mechanical ventilation, except of dynamic compliance on day 3 (28.38 mL/cmH2O in MV vs. 30.67 mL/H2O in HFNC-F, p = 0.032). In addition, the HFNC-F group (5.6%) had a lower rate of ECMO at 28 days than the MV group (17.6%), even after adjustment (adjusted hazard ratio, 0.30; 95% confidence interval, 0.11–0.83; p = 0.045).

Among mechanically ventilated COVID-19 patients, HFNC failure before mechanical ventilation was not associated with deterioration of respiratory failure.

The online version contains supplementary material available at 10.1186/s12931-024-02671-y.