FiO2
Pronunciation: F-I-O-two
Also written as: FiO2 — Fraction of Inspired Oxygen
Fraction of inspired oxygen concentration delivered to a patient, expressed as a decimal or percentage.
Full Definition
FiO2 represents the fraction of inspired oxygen in the gas mixture delivered to a patient receiving respiratory support. It is expressed as a decimal (0.21 to 1.0) or percentage (21% to 100%), with room air being 0.21 or 21% oxygen. In neonatal care, FiO2 is carefully monitored and adjusted to maintain appropriate oxygen saturation levels while minimizing the risk of oxygen toxicity. Preterm infants are particularly susceptible to both hypoxemia and hyperoxemia, requiring precise FiO2 management. The goal is to use the lowest FiO2 necessary to maintain target oxygen saturation ranges.
Usage
Usage note: Always written with subscript 2; distinguish from SpO2 (oxygen saturation) and PaO2 (arterial oxygen pressure).
In Context
- "The ventilator was weaned from FiO2 0.40 to 0.30 as oxygen saturation remained stable." — respiratory therapy note
- "Maintain FiO2 at the lowest level necessary to achieve target saturation ranges for this gestational age." — clinical protocol