(1243) A Statistical Analysis of the Severity Categorization of PaO2/FIO2 and SpO2/FIO2 in ARDS

Introduction: Pulse oximetry is increasingly utilized in managing Acute Respiratory Distress Syndrome (ARDS), particularly in global and resource-limited settings, to enhance disease detection and management. This study examines the comparative effectiveness of PaO2/FiO2 versus SpO2/FiO2 ratios for ARDS diagnosis and explores their correlation.

Methods: This retrospective study, conducted from January 2023 to June 2024, analyzed nine patient visits requiring interventions for moderate to severe ARDS, resulting in 256 arterial blood gas (ABG) samples. We computed summary statistics for ABG parameters and created a contingency matrix to compare ARDS severity categorizations. The chi-squared test assessed the significance of differences in severity categorizations, and the correlation between SpO2/FiO2 and PaO2/FiO2 ratios was calculated.

Results: Of n = 256 samples the relevant parameters included pH (mean = 7.38, 95% CI = 7.36 – 7.39), pO2 (mean = 111.2, 95% CI = 104.54 – 117.86), FiO2 (mean = 73.39, 95% CI = 70.34 – 76.45), SpO2 (mean = 87.36, 95% CI = 85.11 – 89.6). The contingency table revealed significant distribution differences across severity categories (X-squared = 158.64, df = 9, p-value < 2.2e-16). There was a strong positive correlation between PaO2/FiO2 and SpO2/FiO2, with a correlation coefficient (r) of 0.72, an R-squared value of 0.52, and a highly significant p-value (2.6e-42).

Conclusions: SpO2/FiO2 demonstrates a strong correlation with PaO2/FiO2, indicating that SpO2/FiO2 can be a reliable surrogate for PaO2/FiO2 in assessing ARDS. The significant differences in severity categorizations highlight the importance of using both parameters for a comprehensive evaluation. Further research is needed to understand the clinical implications of these findings across different patient populations.