Correlation of Oxygen Index, Oxygen Saturation Index, and PaO(2)/FiO(2) Ratio in Invasive Mechanically Ventilated Adults

BACKGROUND: With the oxygen saturation index (OSI) being a noninvasive surrogate for oxygen index (OI) and P/F ratio, examining the correlation between PaO(2)/FiO(2) (P/F ratio), OI, and OSI in mechanically ventilated adults will benefit in those settings where arterial blood gas monitoring is not readily accessible. MATERIALS AND METHODS: Data were collected for patients ≥18 years who were under invasive (endotracheal intubation) mechanical ventilation at medical or surgical wards in a tertiary care hospital. RESULTS: After natural log transformation, the correlations between P/F ratio and OI (r = −0.94) and OI and OSI (r = 0.82) were strong, but weaker between P/F ratio and OSI (r = −0.69). CONCLUSION: Future bigger studies are needed to evaluate whether monitoring OSI and/or OI over P/F ratio will impact treatment outcomes. HOW TO CITE THIS ARTICLE: Vadi S. Correlation of Oxygen Index, Oxygen Saturation Index, and PaO(2)/FiO(2) Ratio in Invasive Mechanically Ventilated Adults. Indian J Crit Care Med 2021;25(1):54–55.