What does the term 'FiO2' refer to in oxygen therapy?

The term 'FiO2' stands for the "fraction of inspired oxygen," which is a critical concept in oxygen therapy. It quantifies the percentage of oxygen in the air mixture that a patient breathes. In normal atmospheric conditions, the FiO2 is approximately 21%, corresponding to the percentage of oxygen in the ambient air. However, in medical settings, when supplemental oxygen is provided, the FiO2 can be increased, which enhances the amount of oxygen available for absorption in the lungs.

FiO2 is essential for assessing and managing a patient’s oxygen therapy needs because understanding the concentration of oxygen being inhaled helps healthcare providers adjust treatment according to the patient's condition, especially in cases of respiratory distress or hypoxia. Thus, accurate knowledge and application of FiO2 enable optimal therapeutic support for the patient’s respiratory requirements.