Which of the following "oxygen delivery systems" provides the maximum concentration of oxygen to a patient?

Appeared in: GMCH - 2015

Explanation

The non-rebreather mask is a high-flow oxygen delivery device designed to provide the highest possible oxygen concentration to a spontaneously breathing patient.
It can deliver a Fraction of Inspired Oxygen (FiO₂) of 80% to 95% when the flow rate is set to 10–15 L/min.
Its design includes a large reservoir bag and one-way valves that prevent the patient from rebreathing exhaled air and prevent room air from being entrained, thus maximizing the FiO₂.

Option A: The nasal cannula is a low-flow device that delivers a much lower FiO₂ (24%–44%). It is not designed for delivering maximum oxygen concentration.
Option B: The Venturi mask's primary advantage is delivering a precise, fixed FiO₂, not the maximum possible. Its maximum FiO₂ is typically around 60%, which is lower than a non-rebreather mask.
Option D: The partial-rebreather mask delivers a lower FiO₂ (50%–75%) than a non-rebreather mask. It lacks a one-way valve between the mask and the reservoir bag, which allows the patient to rebreathe some of their exhaled air.

Clinical Relevance

Nursing practice connection: Use the key finding related to Oxygen Delivery Systems and FiO₂ Concentration to guide bedside assessment, documentation, and the next nursing action.
Selecting the correct oxygen delivery device is a critical nursing skill to effectively manage a patient's oxygenation status, especially in acute respiratory distress.
A key nursing safety check for a non-rebreather mask is ensuring the reservoir bag is inflated. A collapsing bag indicates an insufficient flow rate, causing the patient to rebreathe CO₂.
What if the patient has a history of COPD and is a known CO₂ retainer? The non-rebreather mask would be used with extreme caution or avoided. A Venturi mask would be a safer choice to provide a precise, lower FiO₂ to avoid suppressing the hypoxic drive.

How to Approach the Question

First, identify the core of the question: it asks for the device that provides the 'maximum concentration' of oxygen.
Mentally review the different types of oxygen delivery systems and their primary purposes.
Categorize the options: Nasal cannula is a low-flow device. The Venturi mask is for precise-flow. The partial and non-rebreather masks are for high-concentration delivery.
Differentiate between the partial and non-rebreather masks. The key difference is the one-way valve system in the non-rebreather, which prevents rebreathing exhaled air and maximizes the inhaled oxygen concentration.
Conclude that the non-rebreather mask is specifically designed to deliver the highest FiO₂, making it the correct answer.

Concept Tested & Keywords

Q9jlyhASQDkW92_66ZufcR

E6 Nursing Fundamentals Taylor p. 731-733

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

Practise the full GMCH - 2015

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