Which medical emergency involves an obstructed airway?

Choking is the medical emergency that specifically involves an obstructed airway. When a person's airway is blocked, typically by a foreign object such as food or another item, it prevents air from reaching the lungs, leading to a life-threatening situation. Recognizing choking is crucial because without immediate intervention, such as the Heimlich maneuver or back blows, the individual may become unconscious due to lack of oxygen and can quickly suffer from severe complications.

In contrast, cardiac arrest involves the heart ceasing to pump effectively, respiratory failure refers to the lungs not being able to provide enough oxygen or remove carbon dioxide, and shock is a state where the body is not receiving adequate blood flow, which can arise from various causes but does not specifically involve an airway obstruction. Therefore, choking is the most accurate answer in relation to obstructed airways.