What it means
Room air is 21% oxygen, so its FiO2 is 0.21. Oxygen devices raise it: a nasal cannula adds roughly 4% for each liter per minute, and masks and ventilators can deliver up to 100% (1.0). On a ventilator or high-flow device, the FiO2 is set directly.
For the nurse
Record the oxygen device and flow rate or FiO2 with every oxygen saturation, so readings can be compared.
In a chart
"On ventilator, FiO2 0.40, SpO2 95%."
At a glance
| Also written | fraction of inspired oxygen, FiO₂ |
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Related terms
pulse oximetry
A painless test that uses light through a finger, toe or earlobe to estimate how much oxygen the blood is carrying.
oxygen
A gas in the air that every cell needs, also given as a medicine at higher amounts than room air.
mechanical ventilation
Breathing support from a machine, a ventilator, that pushes air into the lungs through a tube or a mask.
RA
An abbreviation that can mean rheumatoid arthritis, right atrium or room air.