Base Deficit: What is it?

The base deficit (or excess) is the number of mEq/L of base (or acid) needed to titrate a serum pH back to normal when the contribution of respiratory factors is taken out of the equation. That is, how much acid or base would be required to correct the patient's arterial pH to 7.4 if the pCO₂ were 40, at 37C?

The BD/BE is a quick indication of the metabolic component of the patient's condition. If there is a large base deficit it indicates that even if the patient's respiratory problems were resolved, there is a significant metabolic acidosis.

The BD can be used to calculate the whole body base deficit in the same way you would calculate the amount of sodium to replete in hyponatremia:

BD * 0.5 * kg = mEq of bicarbonate

However, it is recommended that replacement consist of only 0.3 * BD * kg per dose or trials of 1 mEq/kg/dose. These doses should be infused slowly (over 30 to 60 minutes). Bicarbonate should only be administered when adequate ventilation is assured. Generally, it is used to correct the pH up to 7.1.

The BD/BE can be used in conjunction with the other data provided on a blood gas to assess the patient's acid-base status.

Acid-Base

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Last modification: April 30, 1998