The nurse is caring for the client diagnosed with end-stage COPD. Which data warrant immediate intervention by the nurse?

A. The client's sputum is white colored: White sputum may be normal for a client with COPD and often indicates chronic inflammation without infection. It does not signal an acute or emergent issue that requires immediate intervention. B. The client's arterial blood gas CO₂ level is 76 mm Hg: A CO₂ level this high indicates significant hypercapnia, which can lead to respiratory acidosis and altered mental status. This finding reflects serious respiratory compromise and requires prompt intervention to prevent respiratory failure. C. The client's pulse oximeter is 90%: While 90% is on the lower end of acceptable for clients with end-stage COPD, it is often tolerated due to their adapted baseline. It does not represent an immediate threat unless accompanied by other signs of deterioration. D. The client has mild SOB when walking to the bathroom: Mild shortness of breath with exertion is expected in clients with advanced COPD. It reflects baseline activity tolerance and does not require urgent action unless symptoms worsen.