Table 1.
Equations |
[1] CMRO2 = (CBF • CaO2) – (CBF • CvO2) – CiO2 |
[2] Q = ΔP ÷ R |
[3] Q = (π • r4 • ΔP) ÷ (8 η • L) |
[4] Q = CBV ÷ t` |
[5] CBV = 1.09 • CBF0.29 |
[6] OEF = (SaO2 – SjvO2) ÷ SaO2 |
[7] OEF = CMRO2 ÷ (CBF × 1.34 × [Hb] × SaO2) |
Key:
CaO2 is the oxygen content of arterial blood
CBF is the cerebral blood flow
CBV is the cerebral blood volume
CiO2 is the oxygen content of brain tissue
CMRO2 is the cerebral metabolic rate for oxygen
CvO2 is the oxygen content of venous blood
[Hb] is the hemoglobin concentration
η is blood viscosity
L is vessel length
OEF is oxygen extraction fraction of brain
ΔP is the pressure gradient between inflow and outflow
Q is flow
R is resistance to flow
r is vessel radius
SaO2 is oxyhemoglobin saturation of arterial blood
SjvO2 is oxyhemoglobin saturation of jugular venous blood
t` is mean transit time of blood