Intermediate
Technical
IVT
P/F ratio
The ratio of arterial oxygen partial pressure to fraction of inspired oxygen, used to assess oxygenation efficiency.
Full Definition
The P/F ratio (PaO2/FiO2 ratio) is a key metric in respiratory therapy that measures oxygenation efficiency by dividing the partial pressure of oxygen in arterial blood by the fraction of inspired oxygen. A normal P/F ratio is above 300, while values below 200 indicate severe acute respiratory distress. This calculation helps respiratory therapists and clinicians assess lung function and guide ventilator management decisions.
Usage
Usage note: Always expressed as a unitless ratio; avoid adding units like mmHg or percentage.
In Context
- "The patient's P/F ratio of 180 indicated severe hypoxemia requiring immediate intervention." — Clinical assessment note
- "Monitor P/F ratio trends to evaluate response to PEEP adjustments." — Ventilator management protocol
Also known as
PaO2/FiO2 ratio
oxygenation index
Don't confuse with
A-a gradient
oxygen saturation