Correlation of Oxygen Index, Oxygen Saturation Index, and PaO2/FiO2 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 PaO2/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 incubation) 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.