RADIOMETER FLEX ABL90, Reference Manual

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8. Parameters ABL90 FLEX reference manual
8-38
The ODC displacement which is described by "a" and "b" in the coordinate
system (ln(s/(1–s))vsln(p)), is given by the change in p50 from the default to
its actual value in a more common coordinate system (sO
2
, pO
2
).
Eq. Description
46.5
o
x x ln a b
7
p
   
46.6
h
 
h a
o
where h
o
= 3.5
46.7
b 0.055 ( )
o
T T    T
o
= 37 °C
46.8
2
O CO p p M p   
where M  pCO is taken from the Haldane equation  20  :
2
2
O
CO
O Hb COHb
p
p
M
c c
  , to give eq. 46.9
46.9
2
2
2
O COHb
O
O 1 COHb MetHb
p F
p p
s F F
 
   

 
- -
or equation 46.10
46.10
 
2
2
O
COHb
1
O 1 COHb MetHb
p
p
F
s F F


  
The ordinate, s, may loosely be termed the combined
oxygen/carbon monoxide saturation of hemoglobin and is
described by equation 46.11 below:
Eq. Description
46.11
 
2
2
2
O Hb COHb
O Hb COHb HHb
O 1- COHb- MetHb COHb
1 MetHb
c c
s
c c c
s F F F
F


 
 


or
46.12
 
2
1- MetHb COHb
O
1 COHb MetHb
s F F
s
F F
 

 
The ODC
displacement