Acid-Base Disorders USMLE Step 1 Practice Question
A 31-year-old man is found unresponsive with pinpoint pupils and shallow respirations next to an empty oxycodone bottle. Vital signs show BP 92/58, HR 52, RR 8, SpO2 88%. Arterial blood gas reveals pH 7.18, PaCO2 68 mm Hg, HCO3− 25 mEq/L. Chest X-ray shows no infiltrates. He denies recent renal disease. Which acid-base disturbance best describes his condition?
Answer choices
- AChronic respiratory acidosis
- BMixed respiratory alkalosis and metabolic acidosis
- CMetabolic alkalosis
- DAcute metabolic acidosis
- EAcute respiratory acidosisCorrect answer
- FChronic metabolic acidosis with respiratory compensation
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