Predicting factors for the failure of high flow nasal cannula therapy in patients with acute respiratory failure

Abstract

Introduction: The clinical outcome of acute respiratory failure (ARF) treated with high flow nasal cannula (HFNC) may be favorable, but sometimes ARF deteriorates and requires invasive mechanical ventilation (IMV). However, little is known about the factors affecting this difference. Objective: The aim of this study is to investigate the predicting factors for HFNC failure in patients with ARF treated with HFNC. Methods: A cohort of consecutive patients with ARF treated with HFNC was studied. HFNC failure was defined as requiring IMV or death following HFNC. Results: 212 patients were enrolled, of whom 136 (64.2%) required IMV or died (HFNC failure). In univariate analysis, the significant factors associated with HFNC outcome were PaCO2, PaO2, PaO2/FiO2 (P/F) ratio, platelet count, serum C-reactive protein level, APACHE II score, P/F ratio difference (difference of P/F ratio before and after HFNC), and lung infiltration extent (P Conclusions: We demonstrated that APACHE II score over 16.5 and degree of oxygenation improvement (P/F ratio difference below 41.72) were independent predicting factors for HFNC failure. This suggests their role as evaluate criteria in setting indication for early IMV in patients with ARF being treated with HFNC. A larger, prospective study is required to confirm these findings.