RADIOMETER ABL800 FLEX Reference Manual

ABL800 FLEX Reference Manual 6. Parameters
Oxyhemoglobin dissociation curve (ODC)
These equations account for the effect of FCOHb on the shape of the
Oxyhemoglobin Dissociation Curve (ODC) in accordance with the Haldane
equation.
ODC equations
Eq. 46 [16,18]:
(
)
[
]
yy xx htanhkxx
oo o
−=− +× −()
o
where k
o
= 0.5343
Eq. Description
46.1
xln = p
46.2
yln
1-
=
s
s
46.3
yln
1-
o
o
o
=
s
s
where s
o
= 0.867
46.4
xx abln( a
ooo oo
=++= ++p ) b where p
oo
= 7 kPa
The actual position of the ODC in the coordinate system (ln(s/(1–s)) vs ln(p)) used in
the mathematical model, is expressed by equations 46.3 and 46.4.
The symbols 'a' and 'b' reflect the ODC displacement from the reference position to
its actual position in this coordinate system:
'a' describes the displacement at 37 °C.
'b' the additional displacement due to the patient temperature difference from 37 °C.
The ODC
reference
position
The reference position of the ODC was chosen to be the one that corresponds to the
default value for p50(st) = 3.578 kPa, which is traditionally considered the most
likely value of p50 for adult humans under standard conditions, namely:
pH = 7.40
pCO
2
= 5.33 kPa
FCOHb, FMetHb, FHbF = 0
cDPG = 5 mmol/L
Continued on next page
6-43

RADIOMETER ABL800 FLEX Specifications

General

Brand	RADIOMETER
Model	ABL800 FLEX
Category	Measuring Instruments
Language	English