Which of the following is a sign that a patient may require mechanical ventilation during a COPD exacerbation?

Severe breathlessness is a critical indicator that a patient may need mechanical ventilation during a COPD exacerbation. This condition often results from the inability to adequately exchange gases due to obstructed airways or inadequate ventilation. When a patient experiences pronounced breathlessness, it may signal that their respiratory muscles are fatigued, or that there is significant hypoxemia and hypercapnia (elevated levels of carbon dioxide).

In such cases, patients may not be able to maintain sufficient oxygen levels or effectively remove carbon dioxide from the body, potentially leading to respiratory failure. Mechanical ventilation can help support the breathing process, ensuring that the patient receives adequate oxygenation and assists in the removal of carbon dioxide.

Other provided options do not indicate a need for mechanical assistance in the same urgent manner that severe breathlessness does. Stable breathing rates suggest that the patient is managing well without significant respiratory distress, improved color of sputum typically indicates resolving infections or inflammation, and a decrease in coughing episodes might suggest an improvement in airways, not necessarily a deterioration that warrants mechanical ventilation.