Acid-Base Balance and Base Deficit Calculation

Introduction to Base Deficit

Base deficit is calculated from the pH and PaCO2 values using standardized formulas, with normal values ranging from -2 to +2 mEq/L, and values below -2 indicating metabolic acidosis 1
The European Resuscitation Council suggests that sodium bicarbonate therapy may be considered in patients with severe acidosis (arterial pH < 7.1 and base deficit < -10) 2
The American Heart Association notes that bicarbonate therapy should be guided by the bicarbonate concentration or calculated base deficit obtained from blood gas analysis 3

Base deficit (BD) is a calculated parameter that indicates the amount of acid required to titrate blood pH to normal (7.4) at a PaCO2 of 40 mmHg, with negative values (below -2 mEq/L) indicating metabolic acidosis, positive values (above +2 mEq/L) indicating metabolic alkalosis, and a normal range of -2 to +2 mEq/L 1
Base deficit severity can be stratified into three categories: mild (-3 to -5 mEq/L), moderate (-6 to -9 mEq/L), and severe (< -10 mEq/L) 2

Base deficit is valuable for assessing shock severity in trauma patients, monitoring resuscitation adequacy, predicting transfusion requirements and mortality risk, and evaluating the metabolic component of acid-base disorders 1
The best method for reversing acidosis associated with cardiac arrest is to restore spontaneous circulation through effective resuscitation, as noted by the European Resuscitation Council 2

The American Heart Association recommends guiding bicarbonate therapy by the bicarbonate concentration or calculated base deficit obtained from blood gas analysis 3
The European Resuscitation Council suggests considering sodium bicarbonate therapy in patients with severe acidosis (arterial pH < 7.1 and base deficit < -10) 2