A respiratory disorder patient is admitted to the pulmonary ward of the hospital. The patient is diagnosed with an early stage of COPD. The on-duty nursing officer knows that which statement is not true about oxygen administration in a COPD patient?

1. A

   Nasal cannula not more than 2 L/m

2. B

   28% or <4 L/m oxygen delivered via Venturi mask

3. C

   Oxygen saturation maintained between 88-92%

4. D

   Use of high flow oxygen delivery device

Appeared in: NORCET 2 - 2021 (shift-1)

Explanation

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• Venturi masks are fixed-performance devices that require a specific oxygen flow rate to deliver a precise Fraction of Inspired Oxygen (FiO₂).
• To deliver 28% FiO₂, a Venturi mask requires an oxygen flow rate of exactly 4 L/min, not less than 4 L/min.
• Using a flow rate lower than prescribed for a Venturi mask results in an unpredictable, lower FiO₂ and creates a significant risk of the patient rebreathing exhaled carbon dioxide, which can worsen hypercapnia.

Why Other Options Were Wrong

• Option A: This is a true statement. For stable COPD patients, oxygen is often initiated at a low flow of 1-2 L/min via nasal cannula to provide adequate oxygenation without suppressing the hypoxic drive.
• Option C: This is a true statement. The recommended target oxygen saturation for most patients with COPD is 88-92%. This range balances the need for adequate tissue oxygenation with the risk of causing oxygen-induced hypercapnia.
• Option D: This is a true statement. A Venturi mask is itself a high-flow (or more accurately, a fixed-performance) device. Such devices are often preferred for COPD exacerbations because they deliver a precise FiO₂, preventing accidental over-oxygenation. The term 'high flow' refers to the system's ability to meet the patient's total inspiratory demand, not necessarily a high oxygen concentration.

Related Visual

• Visual 1: Diagram - A chart showing different color-coded Venturi mask adapters, their corresponding FiO₂ percentages, and the required oxygen flow rate in L/min. This helps visualize the core concept of fixed performance.
• Visual 2: Illustration - A patient wearing a Venturi mask, with labels pointing to the air entrainment ports and the oxygen inlet tube, explaining how room air is mixed in.

Clinical Relevance

• Nursing practice connection: Use the key finding related to Oxygen therapy guidelines for Chronic Obstructive Pulmonary Disease (COPD) to guide bedside assessment, documentation, and the next nursing action.
• Administering oxygen to COPD patients requires a careful balance to improve hypoxemia without worsening hypercapnia (high CO₂ levels). This is a critical patient safety competency for nurses.
• Nurses must always verify that the oxygen flowmeter is set to the specific rate required for the prescribed Venturi mask adapter to ensure patient safety and therapeutic accuracy.
• It is crucial to differentiate between a high-flow system (like a Venturi mask) and a high concentration (FiO₂) of oxygen. The danger in COPD is high FiO₂, not necessarily the use of a high-flow device.

How to Approach the Question

• First, identify the core of the question: it asks for the INCORRECT statement ('not true') about oxygen therapy in a patient with COPD.
• Second, evaluate each option against your knowledge of COPD pathophysiology, specifically the concept of hypoxic drive and the risk of CO₂ retention.
• Analyze Option A (Nasal cannula ≤ 2 L/m): This is a standard, cautious approach for stable COPD. This statement is likely true.
• Analyze Option C (SpO₂ target 88-92%): This is the evidence-based target range for COPD. This statement is likely true.
• Analyze Option D (Use of high flow device): Venturi masks are high-flow/fixed-performance devices used for precise FiO₂ in COPD. This statement is likely true.
• Analyze Option B (Venturi mask 28% at <4 L/m): Recall that Venturi masks require specific flow rates for each FiO₂ setting to work correctly and prevent CO₂ rebreathing. A 28% mask requires 4 L/min. The phrase '<4 L/m' indicates an incorrect and unsafe procedure. This is the 'not true' statement and therefore the correct answer.

Concept Tested & Keywords

• Concept Tested: Oxygen therapy guidelines for Chronic Obstructive Pulmonary Disease (COPD)
• Stem keywords: COPD, oxygen administration, respiratory disorder
• Lead-in keywords: not true
• Clinical cues: Patient with early-stage COPD
• Clinical cues: Question asks for the incorrect statement

Question ID

QyKD-mNrGllNs_WxyavTCw

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