Which signs indicate respiratory failure?

• A. Normal mental status and stable pulse oximetry.
• B. Productive cough with wheezes.
• C. Altered mental status, cyanosis, dropping pulse oximetry.
• D. Hyperactivity and tachycardia only.

Answer: (C)

When the body can’t maintain adequate gas exchange, signs of respiratory failure appear. Altered mental status happens because the brain is highly sensitive to low oxygen or high carbon dioxide. Cyanosis indicates significant hypoxemia, showing the blood isn’t carrying enough oxygen. A falling pulse oximetry reading confirms that oxygen saturation is decreasing. Put together, these findings point to respiratory failure rather than just distress. The other options describe scenarios that may occur with airway irritation or early distress but don’t demonstrate failure: normal mental status with stable oxygen saturation suggests adequate gas exchange; a productive cough with wheezes can occur with asthma or infection without necessarily indicating failure; hyperactivity and tachycardia can be present in anxiety or early distress and aren’t definitive signs of failure.