A nurse is caring for a client who is receiving oxygen at 5 L/min via nasal cannula and is hypoxic. Which of the following actions is the nurse's priority?

Rationale: A. Prepare to intubate the client with an endotracheal tube: Intubation is an invasive intervention typically reserved for clients with severe or rapidly deteriorating respiratory failure. It is not the first step in managing hypoxia when simpler oxygen delivery methods may be effective. B. Place a nonrebreather face mask: This is the priority action because a nonrebreather mask delivers high-concentration oxygen (up to 95–100%) and can rapidly correct hypoxia. It is the most appropriate next step when a nasal cannula at 5 L/min is insufficient. C. Obtain a prescription for arterial blood gases: While important for assessing the severity of hypoxia and guiding further treatment, this diagnostic action does not immediately address the client’s oxygenation needs. D. Apply noninvasive positive-pressure ventilation: This intervention is beneficial for clients with certain conditions like COPD or heart failure but may not be the first-line response for general hypoxia. A nonrebreather mask is simpler and faster to apply in an acute setting.