Multiple choice Which of the following respiratory sounds is caused by a narrowed or obstructed airway? Wheeze Stridor Crackles Rhonchi Pleural rub Reveal answer Fill a bubble to check yourself B Correct answer Explanation Stridor is a high-pitched breath sound resulting from turbulent air flow in the larynx or lower in the bronchial tree. Stridor is a physical sign, which is caused by a narrowed or obstructed airway.