[1] The Horowitz index was first proposed in a 1974 paper by Joel H. Horovitz and two co-authors, Charles Carrico and G. Tom Shires.
In this study, the authors utilized the PaO2/FiO2 ratio to compare patients treated with varying inspired oxygen concentrations.
The Horowitz ratio has used in scoring systems to grade severity in diseases such as acute respiratory distress syndrome (ARDS), sepsis, and community-acquired pneumonia.
[3] Three severities of ARDS are categorized based on the degree of hypoxemia using the Horowitz index, according to the Berlin definition.
*Table adapted from Ranieri et al.[3] The Horowitz index is used in multiple severity scoring systems in sepsis.