How can stridor be classified based on the timing in the respiratory cycle?

• A. As either inspiratory, expiratory, or biphasic
• B. Only as inspiratory
• C. Only as expiratory
• D. As mechanical or chemical

Answer: (A)

Stridor is typically classified based on the timing of the sound in relation to the respiratory cycle. When assessing stridor, it is important to note whether the sound occurs during inspiration, expiration, or both.

The classification into inspiratory, expiratory, or biphasic categories provides valuable clinical information about the underlying cause of the stridor and where the obstruction is likely to be. For instance, inspiratory stridor often indicates an obstruction in the upper airway, such as in laryngomalacia or croup, while expiratory stridor may suggest issues in the lower airway. Biphasic stridor, which occurs during both inhalation and exhalation, typically points to more severe airway obstruction that can occur at the level of the larynx.

This clear categorization into three distinct types allows healthcare professionals to better understand the nature of the airway compromise and aids in planning the appropriate intervention or management strategy. Other classifications of stridor, such as mechanical or chemical, do not pertain to the timing of sound during the respiratory cycle, which is critical for accurate diagnosis and treatment.