The nurse is preparing to administer oxygen to a client with a diagnosis of chronic obstructive pulmonary disease (COPD) and is at risk for carbon dioxide narcosis. The nurse should administer oxygen by?

1. A

   Venturi mask

2. B

   Nasal cannula

3. C

   NRBM mask

4. D

   Face mask

Appeared in: JIPMER Pondicherry NO - 2022

Explanation

• The Venturi mask is the correct choice because it is a high-flow device that delivers a precise, fixed concentration of oxygen (FiO₂).
• This precision is critical for COPD patients who rely on a 'hypoxic drive' to breathe.
• Administering a controlled amount of oxygen (e.g., 24-28%) prevents suppression of this drive, which would otherwise lead to hypoventilation and carbon dioxide narcosis.
• The mask works by using the Venturi effect, entraining a specific amount of room air to mix with the oxygen flow, ensuring a consistent FiO₂ regardless of the patient's breathing pattern.

Why Other Options Were Wrong

• Option B: A nasal cannula is a low-flow device that delivers a variable FiO₂ (24-44%) that changes with the patient's respiratory rate and tidal volume. This lack of precision is unsafe for a patient at risk for CO₂ narcosis.
• Option C: A non-rebreather mask (NRBM) delivers a very high concentration of oxygen (60-90%). This would almost certainly suppress the hypoxic drive in a patient with chronic CO₂ retention, leading to respiratory arrest.
• Option D: A simple face mask delivers a variable and imprecise oxygen concentration (35-50%). It also requires a flow rate of at least 5-6 L/min to prevent the patient from rebreathing exhaled carbon dioxide, which would worsen hypercapnia.

Related Visual

Clinical Relevance

• Nursing practice connection: Use the key finding related to Oxygen delivery methods for patients with COPD and risk of CO2 narcosis to guide bedside assessment, documentation, and the next nursing action.
• The cornerstone of managing oxygen therapy in chronic CO₂ retainers is 'start low, go slow.' The goal is to correct life-threatening hypoxemia without causing respiratory depression. The target SpO₂ is typically 88-92%.
• Nurses must be vigilant in monitoring for signs of CO₂ narcosis: drowsiness, confusion, headache, and decreased respiratory rate. If these signs develop, the oxygen concentration should be decreased, and the provider notified immediately.
• What if? If a Venturi mask is not available and the patient is hypoxic, the next safest option would be a nasal cannula started at a very low flow rate (e.g., 1-2 L/min), with continuous SpO₂ monitoring and frequent assessment of the patient's neurological and respiratory status, while arranging for a Venturi mask.

How to Approach the Question

• First, identify the key patient condition: COPD with risk of CO₂ narcosis. This immediately signals a special consideration for oxygen therapy.
• Recall the pathophysiology of COPD and the 'hypoxic drive.' Understand that the primary goal is to avoid suppressing this drive.
• Analyze the function of each oxygen delivery device listed in the options. Focus on which device offers the most precise control over the fraction of inspired oxygen (FiO₂).
• Compare the devices: Nasal cannula and simple face mask are low-flow and imprecise. The NRBM is high-flow but delivers too much oxygen.
• Conclude that the Venturi mask, a high-flow device known for its precise FiO₂ delivery via air-entrainment valves, is the only option that safely meets the patient's specific needs.

Concept Tested & Keywords

• Concept Tested: Oxygen delivery methods for patients with COPD and risk of CO2 narcosis.
• Stem keywords: COPD, carbon dioxide narcosis, administer oxygen
• Lead-in keywords: should administer oxygen by
• Clinical cues: The patient has COPD and is at risk for carbon dioxide narcosis, which indicates a need for precise oxygen delivery to avoid suppressing the hypoxic drive.

Question ID

QIt9-g0RhViaw0B3oSD3P0

Copy ID

Reference Book

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

E6 Nursing Fundamentals Taylor p. 731-733

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 663-665