Hamilton G5 - Formulas; E.7 Formulas

624074/07 E-9
E.7 Formulas
Alveolar tidal ventilation (Vtalv)
Vtalv = Vt-VDaw
Alveolar minute ventilation (V’alv)
V’alv =f*Vtalv
Volume of CO
2
eliminated in one breath (VCO
2
)
VCO
2
= VeCO
2
-ViCO
2
Fractional concentration of CO
2
in exhaled gas (FeCO
2
)
FeCO
2
= V’CO
2
/MinVol
Partial pressure of CO
2
in exhaled gas (PeCO
2
)
PeCO
2
= FeCO
2
*(Pb-PH
2
O)
Bohr dead space fraction (VDbohr/Vt) (Note: Vt in this
formula needs to be in ml STPD)
VDbohr/Vt = 1-(VeCO
2
/(Vt*FeCO
2
))
Physiological dead space fraction (VD/Vt)
VD/Vt = 1-((VeCO
2
/Vt)/(paCO
2
/Pb-PH
2
O))