Out of the following methods of oxygen administration system, which method comes under low flow system?

DSSSB - 29 August 2019 (Shift-2)

Medical & Surgical Nursing

Easy

Appeared in: DSSSB - 29 August 2019 (Shift-2)

Explanation

A simple face mask is a low-flow oxygen delivery system because it does not provide the patient's entire inspiratory flow needs.
The oxygen provided is diluted with entrained room air through side ports, resulting in a variable FiO₂ (fraction of inspired oxygen), typically between 35% and 50%.
The final FiO₂ depends on the oxygen flow rate, the fit of the mask, and the patient's respiratory rate and depth.
A minimum flow rate of 5 L/min is required to flush exhaled carbon dioxide from the mask.

Option B: The Venturi mask is a high-flow system, not a low-flow system.
Option C: An oxygen hood is a high-flow system specifically designed for infants.
Option D: A tracheostomy mask (or collar) is typically used as part of a high-flow system to deliver humidified oxygen directly to a patient's artificial airway.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of Oxygen Delivery Systems (Low-Flow vs. High-Flow) as background academic context rather than a clinical decision trigger.
Choosing the correct oxygen delivery system is a critical nursing responsibility. Using a low-flow device when a high-flow, fixed-performance device is needed can lead to inadequate oxygenation or, in some cases (like COPD), respiratory depression.
A key safety consideration for a simple face mask is ensuring the flow rate is at least 5 L/min. Below this rate, the mask can trap exhaled carbon dioxide, leading to rebreathing and hypercapnia.
What if the patient had COPD and required an FiO₂ of 28%? The simple face mask would be inappropriate. The nurse should use a Venturi mask with the 28% (blue) adapter to deliver a precise concentration and prevent CO₂ retention.

How to Approach the Question

First, understand the question's core concept: the classification of oxygen delivery systems.
Recall the key difference between low-flow and high-flow systems. Low-flow systems provide a variable FiO₂ because they don't meet the patient's full inspiratory demand. High-flow systems provide a fixed, precise FiO₂ by meeting or exceeding this demand.
Evaluate each option against this definition.
Simple face mask: Does it provide a fixed FiO₂? No, it has side ports for room air entrainment. This makes it a low-flow system.
Venturi mask: Is it known for precision? Yes, it uses entrainment valves for a fixed FiO₂. This makes it a high-flow system.
Oxygen hood/Tracheostomy mask: Are these used for partial or total respiratory support? They are designed to provide the total required gas flow, making them high-flow systems.

Concept Tested & Keywords

Concept Tested: Classification of Oxygen Delivery Systems (Low-Flow vs. High-Flow)
Stem keywords: oxygen administration, low flow system
Lead-in keywords: which method

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E6 Nursing Fundamentals Taylor p. 731-733

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