Which assessment finding indicates poor air exchange in a patient with a foreign body airway obstruction?

Stridor is a high-pitched, wheezing sound caused by disrupted airflow, often seen when there is an obstruction in the upper airway. In the context of a foreign body airway obstruction, stridor indicates that air is having difficulty moving past the obstruction, suggesting significant narrowing of the airway and poor air exchange. This sound occurs during inspiration when the upper airway is partially blocked, providing a clear indication that immediate attention is needed to relieve the obstruction.

Wheezing is typically associated with bronchoconstriction in the lower airways, which can suggest issues like asthma or bronchitis, rather than a direct airway obstruction caused by foreign objects. Coughing can be a sign of airway irritation or the body's attempt to expel an obstruction, but it doesn't necessarily indicate poor air exchange; in fact, effective coughing can improve air movement. Snoring occurs due to a relaxed airway and is generally more related to sleep patterns than acute airway obstruction.

In summary, stridor clearly signifies that there is a serious obstruction leading to inadequate airflow, making it the most relevant assessment finding in cases of foreign body airway obstruction.