מטופל עם היסטוריה של מחלת ריאות חסימתית כרונית COPD, מקבל טיפול בחמצן 2 ליטר לדקה. רמת הסטורציה לפני שעה 88%. עכשיו יש לו קוצר נשימה ורווי חמצן של 80%. האם האחות צריכה להגדיל את ה-FIO2 (ליטר לדקה) מה שיגדיל גם את אחוז החמצן?

Fraction of inspired oxygen (FIO2), corrected denoted with a capital "I",[1] is the molar or volumetric fraction of oxygen in the inhaled gas. Medical patients experiencing difficulty breathing are provided with oxygen-enriched air, which means a higher-than-atmospheric FIO2. Natural air includes 21% oxygen, which is equivalent to FIO2 of 0.21. Oxygen-enriched air has a higher FIO2 than 0.21; up to 1.00 which means 100% oxygen. FIO2 is typically maintained below 0.5 even with mechanical ventilation, to avoid oxygen toxicity,[2] but there are applications when up to 100% is routinely used. Often used in medicine, the FIO2 is used to represent the percentage of oxygen participating in gas-exchange. If the barometric pressure changes, the FIO2 may remain constant while the partial pressure of oxygen changes with the change in barometric pressure.