High-flow nasal cannula for the management of acute hypoxemic respiratory failure due to COVID-19: A retrospective study

Abstract

INTRODUCTION: COVID-19 is the disease caused by a new coronavirus SARS-CoV-2. Complications
leading to death include acute respiratory distress syndrome and respiratory failure with refractory
hypoxemia. The high-flow nasal cannula (HFNC) has become a prominent respiratory support system in
the treatment of this disease.

OBJECTIVE: to describe our experience with high-flow nasal cannula (HFNC) in acute hypoxemic
COVID-19 respiratory failure.
MATERIAL AND METHODS: A retrospective analytical study was conducted from March 2020 to April
2021. Adults with COVID-19 respiratory failure treated with HFNC were included. The ROX index (ROXi)
was measured at admitted, 4-6, 12 and 24 hours after the start of HFNC. Severity was assessed using the
4C and CURB-65 scale. Failure was defined as the need for Mechanical Ventilation.
RESULTS: Data from 99 patients who required HFNC were analyzed. 67.3% (95% CI 34.6-102.8)
responded to treatment. They had a better clinical condition: lower 4C, CURB-65 and stay [7 (CI95% 6-8)
vs 23 (CI95% 18-28) days, p <0.01] and significant improvement in respiratory rate and ROXi in the first
24 hours. All survived and were discharged. In contrast, those who failed (31.3%) had a mortality of 52%.
52 patients with intubation criteria on admission received HFNC with rescue intention, with success in
63.4%. The predictors associated with success were: lower age, CURB-65 and 4C, and higher ROXi. None
died. The remaining 36.6% required mechanical ventilation and had a critical evolution, 11 of 19 died
(57.8%).
CONCLUSIONS: HFNC was useful for the treatment of respiratory failure COVID-19. The respiratory
rate and iROX are good predictors of success / failure. PAFI <150 mmHg was not a predictor of failure.
The 4C and CURB-65 scales were good predictors of severity.