What physiological change occurs when an infant with laryngomalacia is crying?

In infants with laryngomalacia, the condition is characterized by an abnormality of the laryngeal cartilage, leading to partial obstruction during inspiration, particularly noticeable with stridor—a high-pitched sound resulting from turbulent airflow through the narrowed airway. When these infants cry, the increased respiratory effort and the heightened intensity of airflow exacerbate the stridor due to the dynamic changes in the airway's structure.

Crying causes the laryngomalacia to manifest more severely because it heightens respiratory demand, leading to increased negative intrathoracic pressure. This intensification can result in worsening symptoms of stridor as the laryngeal structures become more collapsible during increased airflow, making the airway obstruction more profound during moments of distress like crying.

In contrast, improvement in feeding, decreased respiratory rate, and increased oxygen saturation do not typically occur in this situation. Feeding might be negatively impacted due to respiratory struggles, the respiratory rate is likely to rise with crying rather than decrease, and oxygen saturation often remains stable but can occasionally be compromised during episodes of significant airway obstruction.