base excess


base ex·cess

a measure of metabolic alkalosis, usually predicted from the Siggaard-Andersen nomogram; the amount of strong acid that would have to be added per unit volume of whole blood to titrate it to pH 7.4 while at 37°C and at a carbon dioxide pressure of 40 mmHg.

base excess

A measure of the nonrespiratory buffers—bicarbonate, haemoglobin, proteins—in blood.
BE refers to a deviation of the buffer base (BB) from normal BB, and is the amount of base in fully oxygenated blood (which is zero at pH 7.4, the normal base value of the blood); it is equal to the amount of a strong acid or base needed to bring the pH in blood to 7.4 at a pCO2 of 40 mmHg—5.3 kPa at 37ºC. The presence of base excess suggests metabolic alkalosis; a base deficit suggests metabolic acidosis. It is defined by the equation BE = actual BB – normal BB.

base ex·cess

(bās eks'es) A measure of metabolic alkalosis; the amount of strong acid that would have to be added per unit volume of whole blood to titrate it to pH 7.4 while at 37°C and at a carbon dioxide pressure of 40 mmHg.