Question: what is the difference between pco2 and paco2?
Answer: In a healthy person breathing room air, the difference between arterial PaCO2 and end-tidal PCO2 is small. ... => Because PaCO2 is usually very close to PCO2 of the perfused alveoli, increased alveolar dead space would lower the end-tidal PCO2 and increase the difference between that and arterial PaCO2.