What is the FiO2 range delivered by a simple mask?

A simple mask typically delivers an FiO2 range of approximately 40% to 55%. This range is determined by the design of the mask, which allows for a mixture of inhaled air and supplemental oxygen. The simple mask's oxygen delivery is influenced by factors such as the flow rate of oxygen and the patient's breathing pattern.

At typical flow rates, when providing oxygen through a simple mask, a higher concentration of oxygen is delivered compared to room air due to the reservoir effect of the mask. This means that as the patient inhales, they draw in some air from the surrounding environment, but also a significant portion of the oxygen that is supplied through the mask. Consequently, the FiO2 provided is often higher than when using devices like nasal cannulas, making the range of approximately 40% to 55% the most accurate representation of what a simple mask can deliver effectively.

Understanding this range is crucial for clinical practice, as it helps healthcare providers select the appropriate device for their patients based on their respiratory needs.