Predicting failure of non invasive ventilation (NIV) and High flow nasal cannula (HFNC) in patients with acute hypoxemic hypocapnic respiratory failure (AHHRF): the usefulness of the standardised PaO2/FiO2 ratio (P/F-st)

Abstract

Purpose: Delayed intubation after NIV/HFNC failure is associated with increased hospital mortality in patients with acute hypoxemic respiratory failure (AHRF). Conventional PaO2/FiO2 ratio (P/F-con) is strong predictor of NIV/HFNC failure in AHRF. No data are available in for acute hypoxemic hypocapnic respiratory failure (AHHRF). We investigate if PaO2/FiO2 ratio standardised for PaCO2 (P/F-st) might be a stronger predictor of HFNC/NIV failure than P/F-con in AHHRF. Patients and Methods: We analysed all consecutive patients with AHHRF (P/F-con Independent predictive value of different P/F-st cut-off (greater or lower 100) was assessed with multivariate analysis adjusted for main confounding clinical-phsyiologic parameters and the type of treatment. Results: 90 AHHRF were recruited (Pneumonia, 51%; ARDS, 23%) and treated with NIV (57,7%),HFNC (13,3%),NIV+HFNC (29%). According to the cut-off lower than 100 P/F-st ratio demonstrated greater predictive accuracy than P/F-con in multivariate analysis (Odds ratio: 4,71 vs 4,22) after adjusting for confounding parameters. Conclusions: This preliminary study suggested the potential useful role of P/F-st in patients with AHHRF to early detect HFNC/NIV failure.