In the alveolar gas equation, which term is subtracted to account for CO2?

Study for the Respiratory Therapy Test. Use flashcards and multiple choice questions, featuring hints and explanations. Prepare for your exam successfully!

Multiple Choice

In the alveolar gas equation, which term is subtracted to account for CO2?

The alveolar oxygen tension depends on how much O2 you breathe in minus the portion tied up by CO2 production. The equation is PAO2 = FIO2 × (PB − PH2O) − (PaCO2 / R). The term subtracted to account for CO2 is PaCO2 divided by the respiratory quotient, R. This reflects how CO2 generation reduces the amount of oxygen available in the alveoli, scaled by R (the ratio of CO2 produced to O2 consumed). The other terms have different roles: PH2O adjusts the inspired O2 for humidification, while Pb and FiO2 determine the inspired O2 but are not the CO2 correction term.

The alveolar oxygen tension depends on how much O2 you breathe in minus the portion tied up by CO2 production. The equation is PAO2 = FIO2 × (PB − PH2O) − (PaCO2 / R). The term subtracted to account for CO2 is PaCO2 divided by the respiratory quotient, R. This reflects how CO2 generation reduces the amount of oxygen available in the alveoli, scaled by R (the ratio of CO2 produced to O2 consumed). The other terms have different roles: PH2O adjusts the inspired O2 for humidification, while Pb and FiO2 determine the inspired O2 but are not the CO2 correction term.

More practice questions