What sign may indicate an upper airway obstruction?

High-pitched stridor is a significant indicator of upper airway obstruction. This sound is generated when air passes through a narrowed airway, often due to obstructions such as swelling, foreign bodies, or other blockages in the upper airway. The characteristic wheezing or stridor signals that there is difficulty with airflow, particularly during inhalation, which can lead to respiratory distress if not addressed promptly.

In contrast, normal respiratory effort, consistent breath sounds, and normal chest expansion indicate that the airway is generally clear and functioning properly. These signs suggest that air is moving freely in and out of the lungs, and there are no major obstructions present. Therefore, the presence of stridor is crucial in identifying potential airway emergencies that require immediate intervention.