Comparison of Predictive Validity of the ROX Index and the m-ROX Index for the HFNC Outcome in ICU Patients with AHRF
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DOI:
https://doi.org/10.61705/yr0jtg12Keywords:
high flow nasal cannula, acute hypoxia respiratory failure, ROX index, m-ROX indexAbstract
Objective: To compare the predictive validity of ROX index and m-ROX index for high-flow nasal cannula (HFNC) outcomes in patients with acute hypoxia respiratory failure (AHRF) admitted to the intensive care unit (ICU).
Methods: All adult patients who received HFNC therapy due to AHRF at Beijing Shijitan Hospital's ICUs from May 2022 to May 2024 were analyzed. Heart rate, peripheral oxygen saturation, fraction of inspiration oxygen, and respiratory rate were collected at 0.5 hours, 6 hours, 12 hours, 18 hours, and 24 hours after HFNC initiation through electronic medical records to calculate the ROX index and m-ROX index. Predictive validity of the two indices to HFNC outcome were analyzed by ROC curve , and the diagnostic efficacy in actual clinical application was compared through clinical decision curve analysis(DCA).
Results:
After 1:1 PSM matching, a total of 100 patients were included in the analysis, with 50 patients in the succeed group and 50 in the failed group. ROC analysis revealed that the predictive validity of both the ROX index( AUROC 0.76, cut-off value 5.7,sensitivity 0.88, specificity 0.57) and m-ROX index ( AUROC 0.79, cut-off value 7,sensitivity 0.78, specificity 0.77) after 6 hour of HFNC initiation were acceptable, and improved over time. No statistical difference in predictive validity between the two indices(p>0.05). The cut-off value for the ROX index varied at subsequent monitoring points(H12: 6.9; H18: 6.25; H24: 6.25), whereas the cut-off values for the m-ROX index remained relatively stable(H12: 7; H18: 7; H24: 6).
DCA analysis demonstrated that both indices exhibited strong predictive validity within the threshold probability range of 0.3 to 1.0. At a threshold probability of 0.6, the m-ROX index displayed equivalent predictive validity to that of the ROX index.
Conclusions: both ROX index and m-ROX index had strong predictive validity for the HFNC outcome.
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