F
Fractional concentration in dry gas
P
Pressure or partial pressure
Q
Volume of blood
Q^.
Volume of blood per unit time (Perfusion)
RQ
Respiratory quotient
S
Saturation of Hb with O2
V
Volume of gas
V^.
Volume of gas per unit time (ventilation)
A
Alveolar
B
Barometric
D
Dead space
E
Expired
I
Inspired
L
Lung
T
Tidal
a
Arterial
c
Capillary
c`
End capillary
i
Ideal
v
Venous
V^_
Mixed venous
PaO2
Partial pressure of O2 in arterial blood
Pv^_O2
Partial pressure of O2 in mixed venous blood
PACO2
Partial pressure of CO2 within the alveoli