OPTi CCA-TS2 - Page 281

Operator’s Manual – OPTI CCA-TS2 A-9
APPENDIX A - TECHNICAL SPECIFICATIONS
st.HCO
3
-
Standard bicarbonate of the blood, dened as the plasma bicarbonate concentration in blood
which has been equilibrated at 37 ºC with a gas mixture having a PCO
2
= 40 mmHg.
( )
st.HCO 10
3
st.pH 6.022
−
−
=
[mmol/L]
6
tCO
2
Total concentration of CO
2
in plasma, the sum of dissolved CO
2
and bicarbonate.
tCO HCO (0.0307 CO )
2 3 2
= + ⋅
−
P
[mmol/L]
7
BE
The base excess of the blood results from a calculation to determine the titratable base of the
blood, which in principle is measured by titration of the blood with a strong acid or base to a pH
of 7.4 with PCO
2
= 40 mmHg at 37 ºC.
( )( )
[ ]
−
+−−⋅+⋅⋅⋅−=
3
HCO24.87.4pH7.7tHb43.1tHb)0.014(1BE
[mmol/L]
7
BE
ecf
The base excess of extracellular uid is a quantity that reects only the non-respiratory
components of acid-base balance (tHb = 5 g/dL).
( )
−
+−−⋅=
3ecf
HCO8.244.7pH2.16BE
[mmol/L]
7
BE
(act)
Base excess at actual oxygen saturation.
( ) ( ) ( )
[ ]






−⋅⋅−
+−−⋅+⋅⋅⋅
−
100
O
1tHb2.0
HCO26.244.7pH5.9tHb63.1tHb0.0143-1=BE
2
3(act)
S
[mmol/L ]
8
7
CLSI. BloodGasandpHAnalysisandRelatedMeasurements;ApprovedGuideline.NCCLS document C46-A,
2001.
8
Zander R., Die korrekte Bestimmung des Base Excess (BE mmol/l) im Blut. Anesthesiol. Intensivmed. Notfallmed.
Schmerzther.