Predicting Failure at Initiation of High‐Flow Nasal Oxygen in Patients With <scp>COVID</scp> ‐19: Literature Review, Development and Internal Validation of a Prediction Model

BACKGROUND AND OBJECTIVE: High-Flow Nasal Oxygen (HFNO) can reduce the need for invasive mechanical ventilation in patients with acute hypoxemic respiratory failure (AHRF) from viral pneumonias, like COVID-19. Early prediction of HFNO failure is useful for timely decision-making at HFNO initiation. This study aimed to develop a prediction model for HFNO failure using predictors available just prior to HFNO initiation in patients with COVID-19 AHRF and compare its performance to existing models. METHODS: This multicenter, prospective observational cohort study included hospitalized patients from 10 centers in the Netherlands between December 2020 and July 2021. Adults who tested positive for SARS-CoV-2, had no treatment limitations, and initiated HFNO for hypoxemia were included. The primary outcome was HFNO failure, defined as the event of endotracheal intubation. Pre-defined candidate predictors were selected by multivariable logistic regression for prediction model development. Internal validation was conducted using bootstrapping. RESULTS: (conventional oxygen 10-15 L/min vs. < 10 L/min: 3.00 [1.71-5.29], 15 L/min vs. < 10 L/min: 4.95 [3.19-7.70]) prior to HFNO initiation. The model C-statistic was 0.767; 95% CI [0.727-0.803], with excellent calibration (intercept: -0.005, slope: 1.001), and stable performance after internal validation. CONCLUSIONS: This newly developed model, using variables available at HFNO initiation, effectively predicted HFNO failure in hospitalized hypoxemic patients due to COVID-19 pneumonia with good performance. REGISTRATION NUMBER CLINICAL TRIAL: Dutch Trial Registry: DTR, NL9067.