A 34-year-old man goes to Peru to take part in an adventure to climb a mountain. He doesn't take any medications and has never had a medical issue. The patient does not consume alcohol, tobacco, or illegal substances. He spends his journey in a mountainous high-altitude camp that is more than 4,000 meters (13,000 feet) above sea level. The patient is given bloodwork by the camp doctor after two days there while inhaling ambient air. Which set of arterial blood gas readings from the list below is most likely to be observed in this patient?

Question

Quizplus · Accepted Answer

Eductional Objective: Because of the low partial pressure of inspired oxygen (PiO₂) at high altitudes, hyperventilation with increased CO₂ exhalation and respiratory alkalosis are caused. The kidneys respond by increasing bicarbonate (HCO₃) excretion, which lowers serum HCO₃ and aids in restoring pH balance. Although hypoxemia continues, physiologic changes are made to enhance O₂ utilization.

A 34-Year-Old Man Goes to Peru to Take Part in an Adventure