Table 3: Compensation formulas for simple acid-base disorders
Acute respiratory acidosis: D[HCO3-] = 0.1xpCO2
Chronic respiratory acidosis: D[HCO3-] = 0.35xpCO2
Acute respiratory alkalosis: D[HCO3-] = 0.2xpCO2
Chronic respiratory alkalosis: D[HCO3-] = 0.5xpCO2
Metabolic acidosis: pCO2 = 1.2x[HCO3-]
Metabolic alkalosis: pCO2 = variable increase
Adapted from Narins and Emmett.4 Normal value of 40 mm Hg for pCO2 or 24 mmol/L for [HCO3-]. Compensation assumes that the kidneys or the lungs are normal; in patients have both respiratory and renal problems, the compensation formulas cannot be applied.