The effects of high-flow nasal cannula oxygen therapy in dyspnea patients with and without hypercapnia in the emergency department: a retrospective, propensity score-matched cohort study

Abstract

We aimed to study the difference in treatment outcomes and prognoses in patients with or without hypercapnia who visited the emergency department for dyspnea and received high-flow nasal cannula (HFNC) therapy. This was a retrospective observational study. Patients who received HFNC therapy were divided into hypercapnic and non-hypercapnic. The intubation rates were compared for the primary outcome. For the secondary outcomes, intensive care unit (ICU) admission, length of hospital stay, length of ICU stay, and mortality were compared. Moreover, changes in arterial blood gas results were reported in terms of group, time, and group-by-time interaction. A total of 517 patients were enrolled, of whom 126 were included in the hypercapnic group. After propensity score matching, 94 patients were selected. The intubation rate was not significantly different between the two groups (p = 0.23). No differences were found in ICU admission, length of hospital stay, length of ICU stay, and mortality. The changes in arterial blood gas results pre- and post-HFNC therapy showed a difference in the group-by-time interaction for partial pressure of carbon dioxide (p = 0.038). We found that there was no difference in treatment outcomes and prognoses in patients with or without hypercapnia who visited the emergency department for dyspnea and received HFNC therapy.