|
Fraction of inspired oxygen (FiO2) is the percentage of oxygen concentration participating in gas exchange in the alveoli[1].
The ratio between partial pressure of oxygen in arterial blood (PaO2) and FiO2 is used as an indicator of hypoxemia per the American-European Consensus Conference on lung injury. A high FiO2 has been shown to alter the ratio of PaO2/FiO2[1].