The Impact of Calculating ROX Index in Delaying Intubation With COVID-19 Patients at King Abdullah Medical City

Abstract

Background: High-flow nasal cannula (HFNC) is an essential treatment for acute respiratory failure (ARF), a key symptom of COVID-19. The ROX index, defined as the ratio of SpO₂/FIO₂ to frequency, is used to predict HFNC success in COVID-19 patients. A ROX score ≥ 4.88 at 12 h indicates a decreased likelihood of needing mechanical ventilation.

Methods: This retrospective observational study analyzed prospectively collected data from 136 COVID-19 patients in the ICUs at King Abdulaziz Medical City (KAMC) from February 1, 2020, to December 30, 2021. Inclusion criteria were adults (≥18 y) with a positive COVID-19 test requiring HFNC. ROX index was calculated every 12 h and correlated with intubation outcomes. Descriptive and inferential statistics were utilized to assess the predictive value of the ROX index.

Results: Out of 136 patients, 46.3% were intubated, and 53.7% were weaned off HFNC. The ROX index varied significantly over the study period, with the highest mean value of 8.22 and the lowest of 4.88. T-test results showed statistically significant mean differences between intubated and weaned-off patients on multiple days, indicating that higher ROX values were associated with successful HFNC therapy. Specifically, a ROX index cut-off point of 5.35 at day 10-2 predicted HFNC success.

Conclusions: The study concludes that the ROX index is a reliable predictor of HFNC success in COVID-19 patients in the ICU. Higher ROX values are linked to a greater chance of successful HFNC therapy and a lower risk of mortality, providing a valuable tool for clinicians in managing ARF in COVID-19 patients.