Advanced Medical Life Support Practice Exam 2025 – Complete Study Guide

The signs exhibited by the firefighter—nausea, pupil dilation, and an unusual breath odor—are indicative of cyanide exposure. Cyanide is a potent chemical asphyxiant that interferes with the body's ability to use oxygen at the cellular level. It can be particularly dangerous in fire situations due to the combustion of materials that release cyanide gas.

Nausea is a common symptom of cyanide poisoning, reflecting the toxin's effect on the gastrointestinal system. Pupil dilation can occur as a part of the body's autonomic response to exertion or stress, especially in cases of toxic exposure, where the sympathetic nervous system may be activated. An unusual breath odor, often described as having a hint of bitter almonds, is classically associated with cyanide intoxication, although not everyone can detect this characteristic smell.

While carbon monoxide is also a concern in fire environments, it typically presents with symptoms such as headache, dizziness, and confusion rather than pupil dilation. Cocaine and ethanol have distinct clinical presentations, including euphoria or altered mental status, which do not align with the symptoms exhibited. Therefore, the combination of symptoms in this scenario most strongly points to cyanide exposure.