What symptom is indicated by the use of accessory muscles during respiration?

The use of accessory muscles during respiration is a clear indication of severe respiratory distress. When a patient is experiencing difficulty breathing, their body may recruit additional muscles—such as those in the neck and shoulders—to assist with ventilation. This is typically a response to increased work of breathing, often seen in conditions like asthma exacerbations, COPD, pneumothorax, or other respiratory illnesses.

In normal or restful breathing, the primary muscles used are the diaphragm and intercostal muscles. However, when a patient requires the use of accessory muscles, it reflects an increased effort to achieve adequate oxygenation and ventilation, highlighting the severity of their respiratory compromise. Therefore, this symptom strongly suggests that the individual is in a state of respiratory distress that requires immediate medical attention.