Which high-pitched respiratory sound indicates an obstruction of the air passageway?

The chosen answer, stridor, is a high-pitched respiratory sound that occurs when there is an obstruction in the airway, typically due to inflammation, swelling, or foreign objects. This sound is often audible without the use of a stethoscope and usually indicates a significant upper airway obstruction, which can be life-threatening if not addressed promptly. Stridor is often associated with conditions such as croup or epiglottitis, where the larynx or trachea is narrowed.

In contrast, rhonchi are lower-pitched, snoring sounds that arise from the larger airways and usually indicate secretions or obstruction in those areas. They are not primarily high-pitched and often clear with coughing. Wheezes, which are high-pitched sounds like stridor, typically occur during expiration and indicate narrowing in the smaller airways, as seen in conditions like asthma, rather than obstruction of the upper airway. A pleural friction rub is a sound caused by the inflamed pleura rubbing against each other, which is associated with conditions affecting the pleura rather than an obstruction in the airway itself. Thus, stridor is distinctly recognized as the sound related to airway obstruction.