In a child with an asthma exacerbation, absence of breath sounds indicates which of the following?

• A. Cardiac arrest
• B. Pneumothorax
• C. Severe airway obstruction
• D. Bronchodilator response

Answer: (C)

Breath sounds reveal how well air is moving through the airways. In an asthma flare, the airways are inflamed and narrowed by bronchospasm and mucus. When obstruction becomes severe, only a tiny amount of air can get through, so the usual sounds may disappear altogether. Absent breath sounds at this point signal that the airway obstruction is extensive and the patient may be moving toward respiratory failure, which requires urgent intervention to open the airways and support breathing.

In contrast, a pneumothorax could also reduce breath sounds, but it’s a separate issue that would present with other clues (often unilateral decreased sounds and possibly chest signs suggestive of a collapsed lung). Cardiac arrest would involve no breathing and no pulse, a situation beyond the scope of asthma alone. A bronchodilator response would typically improve airflow and restore or promote breath sounds, not cause them to vanish.