PAO2, PACO2
Alveolar Partial Pressure
PaO2, PaCO2
Arterial Partial Pressure
FiO2; FAO2
Fractional Concentration of O2 in inspired air and in the alveolus respectively
PIO2
partial pressure of inspired aire
VA
Alveolar Ventilation
Vco2
CO2 production
Vo2
O2 consumption
R
= Respiratory Exchange Ratio = Vco2/Vo2 = Co2 production/oxygen consumption