FiO2
Medical abbreviation · Respiratory
| Stands for | Fraction of inspired oxygen |
|---|---|
| Categories | Medical |
FiO2 stands for Fraction of inspired oxygen, a respiratory abbreviation.
Proportion of oxygen in the gas a patient breathes, expressed as a decimal or percentage: room air is 0.21 (21 percent), and ventilators can deliver up to 1.0 (100 percent). It is a core setting on ventilators and high-flow systems and a key part of oxygenation calculations.
Example: Weaned FiO2 from 0.6 to 0.4 overnight with SpO2 93 to 95%.
Usage notes
Prolonged exposure to a high FiO2, above about 0.6, can cause oxygen toxicity and absorption atelectasis, so clinicians lower it to the minimum needed. Recent trials have compared conservative and liberal oxygen targets in critically ill patients. FiO2 is the denominator of the P/F ratio. Capitalization is conventionally FiO2, with the "i" lowercase.
Related abbreviations
More respiratory abbreviations
- EBUS – Endobronchial ultrasound
- EIB – Exercise-induced bronchoconstriction
- ESS – Epworth Sleepiness Scale
- FeNO – Fractional exhaled nitric oxide
- FEV1 – Forced expiratory volume in 1 second
- FEV1/FVC – Ratio of forced expiratory volume in 1 second to forced vital capacity
- FRC – Functional residual capacity
- FVC – Forced vital capacity
- GGO – Ground-glass opacity
- GINA – Global Initiative for Asthma
- GOLD – Global Initiative for Chronic Obstructive Lung Disease
- HCAP – Healthcare-associated pneumonia
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This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.