What happens to pO2 and pCO2 levels for each degree of fever in the patient?

• A. pO2 will rise 3% and pCO2 will fall 7%
• B. pO2 will fall 7% and pCO2 will rise 3%
• C. pO2 and pCO2 will rise 7% and 3% respectively
• D. pO2 and pCO2 will fall 3% and 7% respectively

Answer: (B)

When a patient has a fever, the body's metabolic rate increases, which affects gas exchange and the balance of oxygen and carbon dioxide. For each degree Celsius of fever, it is observed that the partial pressure of oxygen (pO2) typically falls, while the partial pressure of carbon dioxide (pCO2) tends to rise.

This occurs because the elevated metabolic rate increases the demand for oxygen and enhances the production of carbon dioxide as a byproduct of metabolism. The body responds to increased activity by using oxygen more rapidly, leading to a decrease in the available oxygen in the blood, hence the drop in pO2 levels. At the same time, the body generates more carbon dioxide, resulting in higher levels of pCO2.

Therefore, with a rise in body temperature due to fever, pO2 decreases by about 7%, indicating a diminished level of oxygen available. Conversely, pCO2 rises by about 3%, reflecting the increased production of carbon dioxide as a result of heightened metabolism. This physiological response helps to explain why the correct answer outlines a decrease in pO2 alongside an increase in pCO2 during instances of fever.