While using a simple mask, the oxygen concentration should be:

Appeared in: UP NHM CHO 7 Sept 2022 (Shift-2)

Explanation

A simple face mask is a low-flow oxygen delivery system designed for short-term use.
It delivers a moderate oxygen concentration (FiO₂) ranging from 40% to 60%.
This concentration is achieved with a flow rate of 5 to 8 L/min.
A crucial safety measure is maintaining a minimum flow rate of 5 L/min to flush exhaled carbon dioxide from the mask and prevent rebreathing.

Option B: This oxygen concentration is below the 21% found in room air and would be clinically inappropriate for oxygen therapy.
Option C: This high oxygen concentration range is delivered by devices with a reservoir bag, such as a partial rebreather or non-rebreather mask.
Option D: This concentration is only slightly above room air (21%) and is characteristic of a nasal cannula at a very low flow rate (e.g., 1 L/min).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Oxygen delivery devices and their corresponding FiO2 levels as background academic context rather than a clinical decision trigger.
Selecting the correct oxygen delivery device is critical to match the patient's oxygen needs without causing complications like oxygen toxicity or CO₂ retention.
The minimum flow rate of 5 L/min for a simple mask is a critical safety parameter. Failure to adhere to this can lead to hypercapnia (elevated CO₂ levels) as the patient rebreathes their exhaled air.
Nurses must monitor for signs of skin breakdown on the face and behind the ears due to pressure from the mask and straps, especially during prolonged use.

How to Approach the Question

Identify the keywords in the question: 'simple mask' and 'oxygen concentration'.
Recall the different types of oxygen delivery systems and their associated FiO₂ ranges (low-flow vs. high-flow).
Remember that a simple mask is a low-flow device for moderate oxygen concentrations.
Compare the given options to the known FiO₂ range for a simple mask (40-60%).
Eliminate the other options by associating them with different devices (nasal cannula, non-rebreather mask) or recognizing them as clinically inappropriate (less than room air).

Concept Tested & Keywords

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E6 Nursing Fundamentals Taylor p. 731-733

E6 Nursing Fundamentals Potter Perry 12e Part 5 p. 7-9

Practise the full UP NHM CHO 7 Sept 2022 (Shift-2)

Attempt every question from this paper in a timed mock, then review the full solution for each one.