The device that can deliver oxygen at concentrations of 90-100% is the:

Appeared in: GMCH - 2016

Explanation

A non-rebreathing mask is designed to deliver the highest possible oxygen concentration to a spontaneously breathing patient.
It features a reservoir bag and one-way valves that prevent the patient from inhaling room air or rebreathing significant amounts of exhaled carbon dioxide.
With a proper fit and a high flow rate (10–15 L/min), it can deliver an inspired oxygen fraction (FiO₂) approaching 95-100%, making it suitable for severe hypoxemia.

Option A: A Venturi mask is a high-flow device that delivers a precise, but lower, oxygen concentration, typically between 24% and 50%.
Option B: A partial rebreathing mask delivers a moderate oxygen concentration, usually in the range of 40% to 70%.
Option D: A nasal cannula is a low-flow device that delivers a low oxygen concentration, typically between 24% and 44%, depending on the flow rate and the patient's breathing pattern.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Oxygen delivery systems and FiO₂ concentration as background academic context rather than a clinical decision trigger.
Selecting the correct oxygen delivery device is a critical nursing responsibility. Using a non-rebreathing mask is indicated in emergencies like acute respiratory failure, carbon monoxide poisoning, or trauma to rapidly correct severe hypoxemia.
A nurse must continuously monitor the reservoir bag to ensure it remains inflated; a collapsing bag indicates the flow rate is too low, causing the patient to rebreathe CO₂.
What if? If a patient with a history of COPD develops acute respiratory distress, a non-rebreathing mask might be used for initial stabilization, but a Venturi mask would be preferred for ongoing management to provide a precise, low FiO₂ and avoid suppressing the hypoxic drive.

How to Approach the Question

First, identify the key requirement in the question: an oxygen concentration of 90-100%.
Second, recall the different types of oxygen delivery systems listed in the options.
Third, compare the maximum FiO₂ delivery capability of each device: Nasal cannula (low), Venturi mask (precise, low-to-moderate), Partial rebreather (moderate-to-high), and Non-rebreather (highest).
Finally, select the device that is specifically designed to deliver the highest oxygen concentration, which is the non-rebreathing mask.

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 GMCH - 2016

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