RADIOMETER ABL90 FLEX - The ODC Displacement

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
xx ln ab
7
p
 
46.6
h ha
o
where h
o
= 3.5
46.7
b0.055( )
o
TT T
o
= 37 °C
46.8
2
OCOpp Mp
where M  pCO is taken from the Haldane equation 20:
2
2
O
CO
OHb COHb
p
p
M
cc
 , to give eq. 46.9
46.9
2
2
2
O
COHb
O
O1COHbMetHb
p
F
pp
sFF







--
or equation 46.10
46.10

2
2
O
COHb
1
O 1 COHb MetHb
p
p
F
sFF


 
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
OHb COHb
OHbCOHbHHb
O 1- COHb- MetHb COHb
1MetHb
cc
s
cc c
sFF F
F






or
46.12


2
1- MetHb COHb
O
1COHbMetHb
sF F
s
FF



The ODC
displacement