base excess
The difference between the normal and the actual buffer base concentration in a blood sample when titrated by strong acid at pH = 7.40 and Pco2 = 40 mm Hg. The base excess is usually determined indirectly using measured values for pH and Pco2 and then calculated using known relationships.
b. e. of blood The substance concentration of base in whole blood determined at a pH of 7.40 and Pco2 of 40 mm Hg. This measurement helps one assess the relative contribution of respiratory versus metabolic components in acid-base imbalances in the blood.
ABBR: BE (ecf)
The substance concentration of base in extracellular fluid determined at a pH of 7.40 and Pco2 of 40 mm Hg. Because this quantity cannot be determined directly, a model of extracellular fluid is used as a basis. The model consists of one volume of blood plus two volumes of plasma. As with the base excess of blood, this quantity helps one assess the respiratory versus metabolic components in acid-base balance. In contrast to the base excess of blood, the base excess of extracellular fluid is said to be more representative of the acid-base status of the accessible fluid compartment and thus more appropriate for deciding on and evaluating therapy.