Predictors of successful separation from high-flow nasal oxygen therapy in patients with acute respiratory failure: a retrospective monocenter study

Abstract

Background: High-flow nasal oxygen therapy (HFOT) is a promising first-line therapy for acute respiratory failure. However, its weaning has never been investigated and could lead to unnecessary prolonged intensive-care unit (ICU) stay. The aim of this study is to assess predictors of successful separation from HFOT in critically ill patients. We performed a retrospective monocenter observational study over a 2-year period including all patients treated with HFOT for acute respiratory failure in the ICU. Those who died or were intubated without prior HFOT separation attempt, who were treated with non-invasive ventilation at the time of HFOT separation, or who received HFOT as a preventive treatment during the post-extubation period were excluded.

Results: From the 190 patients analyzed, 168 (88%) were successfully separated from HFOT at the first attempt. Patients who failed separation from HFOT at the first attempt had longer ICU length of stay than those who succeeded: 10 days (7-12) vs. 5 (4-8), p < 0.0001. Fraction of inspired oxygen (FiO2) ≤ 40% and a respiratory rate-oxygenation (ROX) index (calculated as the ratio of SpO2/FiO2 to the respiratory rate) ≥ 9.2 predicted successful separation from HFOT with sensitivity of 85% and 84%, respectively.

Conclusions: FiO2 ≤ 40% and ROX index ≥ 9.2 were two predictors of successful separation from HFOT at the bedside. Prospective multicenter studies are needed to confirm these results.

Keywords: High-flow nasal oxygen therapy; Intensive-care units; Length of stay; Observational study; Oximetry; Ventilator weaning.

Conflict of interest statement

AWT reports travel expenses to attend scientific meetings by Fisher and Paykel, Covidien, General Electrics, and Maquet-Getinge. J-PF reports consulting fees from Fisher and Paykel. RC reports travel expenses to attend scientific meetings by MSD and Fisher and Paykel. MR, FB, AV, SLP, and RR report no competing interests.

Figures

Fig. 1

Flow chart of patients included over the study period

Fig. 2

Last physiological parameters recorded at the bedside under high-flow nasal oxygen therapy before the first separation attempt. a Box-plot of FiO2 according to the success or failure of the first separation attempt (p = 0.02). b Box-plot of the ROX index according to the success or failure of the first separation attempt (p = 0.002)