A 26-year-old man travels from Boston to a ski resort at 3500 meters elevation. On the second day he develops lightheadedness and paresthesias but is otherwise healthy. Arterial blood gas shows pH 7.48, PaCO2 30 mm Hg, and HCO3− 22 mEq/L. Which of the following is the primary cause of his acid-base abnormality?
- A)Increased production of ketoacids
- B)Decreased alveolar ventilation due to hypoxia
- C)Hyperventilation triggered by hypoxemiaGABARITO
- D)Excess renal bicarbonate generation
- E)Loss of hydrogen ions from vomiting
Explicação
At high altitude, low ambient oxygen stimulates peripheral chemoreceptors, causing hyperventilation and a primary respiratory alkalosis. The reduced PaCO2 is the key finding, and renal compensation gradually lowers bicarbonate if the exposure continues. Ver explicação completa e trilha adaptativa →