Standard Bicarbonate Concentration (SBC)
The Standard Bicarbonate is dened as the bicarbonate
concentration of the plasma of whole blood equilibrated
to a PCO
2
of 40 mmHg at a temperature of 37 °C with
the hemoglobin fully saturated with oxygen. Standard
bicarbonate is calculated as follows:
SBC = 24.5 + 0.9Z + Z ( Z - 8 )(0.004 + 0.00025 [Hb])
Equation 21
where Z = [BE-B] - 0.19 [Hb] ((100 - SO
2
)/100)
[Hb] = The hemoglobin value which is measured, manually
entered, or is the 14.3 g/dL default value
Base Excess Extracellular Fluid (BE-ECF)*
The Base Excess Extracellular uid is a corrected form
of the Base Excess Blood in which allowance has been
made for the fact that blood is only approximately 37% of
the extracellular uid volume. Base excess is calculated
as follows:
BE-ECF = [HCO
3
-
]- 25 + 16.2 (pH - 7.40) Equation 22
* The equations are from Reference 2.
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