RADIOMETER ABL800 FLEX - Quality Control

6. Parameters ABL800 FLEX Reference Manual
Oxyhemoglobin dissociation curve (ODC), Continued
The ODC
displacement
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
xx ln
7
ab
o
−= −−
p
46.6
h =+h
o
a
)
where h
o
= 3.5
46.7
b =×−0 055.(TT
o
T
o
= 37
o
C
46.8
pp p=
+
×
OC
2
M O
where M×pCO is taken from the Haldane equation [20]:
p
c
p
c
O
OHb
CO
COHb
2
2
=×M , to give eq. 46.9
46.9
pp
p
s
F
-F -F
=+×
⎡
⎣
⎢
⎤
⎦
⎥
O
O
O
COHb
1 COHb MetHb
2
2
2
or equation 46.10
46.10
(
)
[
]
p
ps F F
F
O
O COHb MetHb
COHb
2
2
=
××− −
+
1
1
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
( )
s
cc
cc c
sFF F
F
=
+
++
=
×+
−
OHb COHb
OHb COHb HHb
O 1 - COHb - MetHb COHb
MetHb
2
2
2
1
or
46.12
(
)
s
sF F
F
F
O
1- MetHb COHb
COHb MetHb
2
=
×−
−
−
1
Continued on next page
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