COPD USMLE Step 1 Practice Question
A 26 year old man travels from Boston to a ski resort in Colorado at 3200 meters above sea level. On the first day he develops headache and tachypnea. Two days later his tissues are extracting oxygen more effectively despite the lower ambient oxygen tension. Which of the following best explains the later improvement in tissue oxygen delivery?
Answer choices
- AIncreased 2,3 bisphosphoglycerate in erythrocytesCorrect answer
- BDecreased hypoxic pulmonary vasoconstriction
- CDecreased 2,3 bisphosphoglycerate in erythrocytes
- DDecreased minute ventilation due to renal compensation
- EIncreased surfactant production by type I pneumocytes
- FErythropoietin-driven polycythemia increasing red cell mass
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