RADIOMETER ABL800 FLEX - Limitations of Use and Interfering Substances

ABL800 FLEX Reference Manual 1. Potentiometric measuring principles
pCO
2
electrode, Continued
Drift (continued)
The default drift tolerances set by Radiometer are as follows:
• for Drift 1 are ± 0.33 kPa (2.5 mmHg)
• for Drift 2 are ± 0.67 kPa (5.0 mmHg)
The pCO
2
value for a sample is calculated from the following equations:
Measurement
theo),COSens(prev),COSens(
Gas1)E(COupdi)sample,E(CO
22
22
22
10)gas1(CO)updsample,(CO
pp
pip
×
−
×=
δ =−ppCO (sample,upd30) CO (sample,upd1
2 2
)
[
]
predict
CO (sample,upd6) CO (sample,upd30 CO (sample,upd18
CO (sample,upd6 CO (sample,upd30) CO (sample,upd18)
2 2 2
22 2
=
×−
+−×
pp
pp p
))
)
p
2
2
For δ < 1.33 kPa, pCO
2
(sample) = pCO
2
(sample,upd30)
For 1.33 kPa < δ < 2.66 kPa
p
p
CO (sample)
predict CO (sample,upd30)
2
2
=
×
−
+
×
−
(.) (.
.
)
δ
δ
133 266
133
For δ ≥ 2.66 kPa, pCO
2
(sample) = predict.
The pCO
2
measured on a sample is then corrected for systematic deviations from
the reference method using the following equations:
Corrections -
blood samples
Equation A:
pCO
2
(sample,corr) = A
3
× pCO
2
(sample)
3
+ A
2
× pCO
2
(sample)
2
+
+ A
0
× pCO
2
(sample) + A
1
× (B − pH
2
O)
and
Equation B:
pCO
2
(sample,corr) = B
1
× pCO
2
(sample) + B
0
where: pCO
2
(sample) = uncorrected value of pCO
2
in the sample.
pCO
2
(sample, corr) = corrected value of pCO
2
in the sample.
A
0
= correction factor
A
1
= correction factor
A
2
= correction factor
A
3
= correction factor
Continued on next page
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