In a respiratory disorder causing a check-valve obstruction, which symptoms will be present?

• A. Air entry on inspiration with expiratory occlusion
• B. Complete obstruction on inspiration and expiration
• C. Narrowing of the lumen with increased air flow resistance
• D. Obstruction of air entry with unimpeded expiratory air flow

Answer: (A)

A check-valve obstruction acts like a one-way valve in the airway: it lets air slide in during inspiration but blocks it from escaping during expiration. Because of this, air enters the lungs with each breath, but expiration is hindered, leading to air trapping and progressive hyperinflation. So the hallmark pattern is air entry on inspiration with expiratory occlusion. The other patterns describe either a fixed or non-directional obstruction or expiration being unimpeded, which doesn’t fit the one-way behavior of a check-valve mechanism.