Asthma USMLE Step 1 Practice Question
A 32-year-old man is brought to the emergency department after heroin overdose. Vital signs show BP 98/62, HR 52, RR 6, temperature 35.8°C, SpO2 84% on room air. Arterial blood gas reveals PaO2 58 mm Hg and PaCO2 62 mm Hg. Chest X-ray shows bilateral pulmonary edema. Pupils are severely constricted. No recent asthma or COPD history is documented. Which of the following additional findings is most likely?
Answer choices
- AMarked improvement in oxygenation only with inhaled nitric oxide
- BNormal A a gradient due to pure hypoventilationCorrect answer
- CNormal PaCO2 because only oxygen exchange is affected
- DHigh DLCO due to alveolar hemorrhage
- EElevated A a gradient due to diffusion impairment
- FElevated A a gradient due to acute respiratory distress syndrome from aspiration
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.