[Campbell Biology P.998] A doctor might give bicarbonate HCO3⁻ to a patient who is breathing... | Practice Question

A doctor might give bicarbonate HCO3⁻ to a patient who is breathing very rapidly. Based on this medical intervention, which of the following is the most logical assumption about the patient's underlying blood chemistry that the doctor is making?

  • A: The patient is experiencing respiratory alkalosis due to hyperventilation.
  • B: The patient is experiencing metabolic acidosis, and the rapid breathing is a compensatory mechanism.
  • C: The patient has an excess of CO2 in their blood, leading to respiratory acidosis.
  • D: The patient needs increased oxygen transport capacity in their blood.

Explanation

Rapid breathing hyperventilation expels CO2, which shifts the carbonic acid-bicarbonate buffer system equilibrium to the left, decreasing H+ concentration and increasing blood pH leading to respiratory alkalosis . If a doctor gives bicarbonate a base to a rapidly breathing patient, it implies the patient is acidotic low pH and needs more base. The rapid breathing would then be a compensatory mechanism to metabolic acidosis, where the body attempts to blow off more CO2 to raise the pH. Administering bicarbonate directly helps correct the underlying metabolic acidosis.