Characteristics and outcomes of patients receiving high flow nasal cannula therapy prior to mechanical ventilation in COVID-19 respiratory failure: A prospective observational study

BACKGROUND: Treatment strategies for acute hypoxic respiratory failure secondary to coronavirus 2019 disease (COVID-19) had significant variation early in the pandemic. We sought to determine if patients treated with high flow nasal cannula (HFNC) prior to mechanical ventilation had differing outcomes compared to those treated only with conventional oxygen. METHODS: This was a prospective, observational study of patients with COVID-19 admitted to a tertiary care medical center with a diagnosis of acute hypoxic respiratory failure. Adult patients with a positive polymerase chain reaction test for COVID-19 who required mechanical ventilation were included. RESULTS: A total of 91 patients met the inclusion criteria for our study. The mean age was 68.4 years (standard deviation [SD] ± 12) and 58% were male. The mean initial partial pressure of arterial oxygen to fraction of inspired oxygen (PaO2/FiO2) ratio was 152 (SD ± 65) and was not significantly different between the HFNC group and the conventional oxygen strategy group (P = 0.95). The observed mortality rate was 30% in the HFNC group versus 52% in the conventional oxygen strategy group (P = 0.05). The multivariate odds ratio of mortality for patients on HFNC was 0.375 compared to a conventional oxygen strategy (95% confidence interval 0.122–1.151, P = 0.09). CONCLUSIONS: While HFNC appears to be safe as the initial treatment strategy for COVID-19 associated respiratory failure, HFNC did not result in a statistically significant difference in mortality compared to a conventional oxygen strategy. Further studies are needed to confirm these findings.