Under which of the following conditions can the alveolar partial pressure of carbon dioxide (PACO₂) be increased?
1) When the body increases its production of CO₂ (VCO₂)
2) When the dead space ventilation per minute is increased (V_D)
3) When the minute ventilation is inadequate (V_E)
4) When the alveolar ventilation is decreased (V_A)

Question

Quizplus · Accepted Answer

All of the listed conditions can lead to an increase in the alveolar partial pressure of carbon dioxide (PACO2). 
1) Increased production of CO2 will increase its concentration in the blood and ultimately result in an increased PACO2.
2) An increase in dead space ventilation (ventilation that does not participate in gas exchange) will result in less effective removal of CO2 and can lead to an increased PACO2.
3) Inadequate minute ventilation (the volume of air breathed per minute) compared to metabolic demand will result in CO2 accumulation and an increased PACO2.
4) Decreased alveolar ventilation (the volume of air exchanged in the alveoli) will reduce the ability to remove CO2 and thus increase PACO2.

Under Which of the Following Conditions Can the Alveolar Partial