Volume OXygenation index in predicting the efficacy of early non-invasive ventilation in patients with acute hypoxic respiratory failure: A multicenter study.

BACKGROUND

The Volume OXygenation (VOX) index was initially designed to predict treatment failure of high-flow nasal cannula therapy. However, its predictive power for non-invasive ventilation (NIV) remains uncertain.

OBJECTIVES

To evaluate the predictive capability of the VOX index regarding treatment failure in patients undergoing NIV.

METHODS

This retrospective study was conducted in three hospitals from September 2017 to September 2021. Patients with acute hypoxic respiratory failure (AHRF) who underwent early NIV treatment were categorized into high-risk and low-risk groups based on the 2-hour NIV VOX Youden index.

RESULTS

At 2 h of NIV, the area under the receiver operating characteristic curve for predicting NIV failure using the VOX index was 0.843 (95 % CI 0.805-0.882). Using a VOX value threshold of 20.45 to predict NIV failure, the sensitivity was 69.1 %, and the specificity was 94.4 %. Following NIV treatment, the low-risk group had a lower intubation rate (7.98 % vs. 77 %, P < 0.05) and mortality rate (4.79 % vs. 17.5 %, P < 0.05).

CONCLUSION

In early NIV treatment for AHRF, the VOX index obtained after 2 h of NIV demonstrates a strong predictive power for NIV failure. Patients with a VOX value > 20.45 have a low probability of NIV failure, suggesting that it can be used as an evaluation index to assess the efficacy of NIV.