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?
- A)Marked improvement in oxygenation only with inhaled nitric oxide
- B)Normal A a gradient due to pure hypoventilationGABARITO
- C)Normal PaCO2 because only oxygen exchange is affected
- D)High DLCO due to alveolar hemorrhage
- E)Elevated A a gradient due to diffusion impairment
Explicação
Opioid overdose causes alveolar hypoventilation, which lowers alveolar oxygen and raises carbon dioxide without creating a primary V Q mismatch. Therefore the A a gradient remains normal. A widened A a gradient would suggest diffusion impairment, shunt, or V Q... Ver explicação completa e trilha adaptativa →