RADIOMETER FLEX ABL90, Reference Manual

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ABL90 FLEX reference manual 8. Parameters
8-35
In the calculations the following are assumed: pH = 7.4, pCO
2
= 5.33 kPa,
FCOHb = 0, FMetHb = 0, cDPG = 5 mmol/L, and temp = 37 °C.
Eq. Description See…
49.1 An estimate of FHbF is made: FHbF
est
= 0.8
49.2 pO
2
,
est
= ODC (sO
2
,A,T); Eq. 47
where the constant A depends on FHbF = FHbF
est
49.3 sO
2
(for fetal blood) = ODC (pO
2
,
est
, A,T); Eq.47
where FHbF = 1
49.4 cO
2
HbF
est
= sO
2
(fetal blood)  ceHb  FHbF
est
49.5
eHb
HbF O HbF O
HbF
est 2 meas. 2
est
c
c c
F

 
49.6 If  FHbF
est
  0.001, proceed to 49.7.
If  FHbF
est
 < 0.001, proceed to 49.9.
49.7 FHbF
est, new
= FHbF
est, old
+  FHbF
est
49.8 Return to 49.2.
49.9 End of iteration. The value for FHbF has converged.
Eq. 50 [8,18]:
The ODC is determined as described in equations 46-47 in Oxyhemoglobin
Dissociation Curve further in this chapter.
pO
2
(x) is calculated by a numerical method, using:
Eq. Description See…
50.1 S = ODC(P,A,T) Eq. 47
50.2
 
2,i
1 MetHb COHb
O ( )
1 COHb MetHb
S F F
s T
F F
  

 
Eq. 46.12
50.3
 
2,i
2,i
P
O ( )
COHb
1
O ( ) 1 COHb MetHb
p T
F
s T F F


  
Eq. 46.10
50.4
 
i 2,i
2 2,i
t ( ) tHb 1 COHb MetHb O ( )
+ O ( ) O ( )
T c F F s T
T p T

     

50.5
 
pH
A a 1.04 37.0
( )
T
T

    

Eq. 20
50.6 T = patient temperature
50.7
 
2 5
) 37 ( 10 21 ) 37 ( 115 . 0
2
0105 . 0 ) ( O
      

 
T T
e T

50.8
2,i 2
O = O (x, ) p p T
when t
i
(T) = ctO
2
(37  C)  2.3 mmol/L
pO
2
(x,T) is calculated in accordance with OSA V3.0.
pO
2
(x,T) can only be calculated if the measured sO
2
(a)  0.97.
pO
2
(x,T) is tagged with "?" if any of the following parameters: sO
2
, FMetHb,
FCOHb, pO
2
, pCO
2
, pH or ctHb is tagged with "?".
pO
2
(x,T)