Which statement is NOT a component of the Oxygen Index (OI) formula?

Which statement is NOT a component of the Oxygen Index (OI) formula?

• A. Paw
• B. FiO2
• C. PaO2
• D. PaCO2

Answer: (D)

The Oxygen Index measures how well oxygenation is functioning given the level of respiratory support. It combines three pieces of information: the mean airway pressure (Paw), which reflects the amount of pressure used to deliver breaths; the fraction of inspired oxygen (FiO2), which shows how much oxygen is being delivered; and the arterial oxygen tension (PaO2), which indicates how much oxygen is actually in the blood. PaCO2, on the other hand, represents ventilation and CO2 removal, not the efficiency of oxygen transfer relative to support. Because OI is intended to quantify oxygenation relative to support, PaCO2 isn’t part of the calculation. Thus PaCO2 is not a component of the Oxygen Index.

The Oxygen Index measures how well oxygenation is functioning given the level of respiratory support. It combines three pieces of information: the mean airway pressure (Paw), which reflects the amount of pressure used to deliver breaths; the fraction of inspired oxygen (FiO2), which shows how much oxygen is being delivered; and the arterial oxygen tension (PaO2), which indicates how much oxygen is actually in the blood. PaCO2, on the other hand, represents ventilation and CO2 removal, not the efficiency of oxygen transfer relative to support. Because OI is intended to quantify oxygenation relative to support, PaCO2 isn’t part of the calculation. Thus PaCO2 is not a component of the Oxygen Index.