Compensatory responses for acid-base disorders
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Compensatory changes for acid-base disorders include respiratory compensation and renal compensation.
Adequacy of compensatory responses for acid-base disorders
| Primary Deficit | Expected Ranges of Compensation | Limits of Compensation |
|---|---|---|
| Respiratory acidosis | Acute: Δ[HCO3-] = + 0.1 mEq/L x ΔPCO2 | [HCO3-] = 38 mEq/L |
| Chronic: Δ[HCO3-] = + 0.25 to 0.5 mEq/L x ΔPCO2 | [HCO3-] = 45 mEq/L | |
| Respiratory alkalosis | Acute: Δ[HCO3-] = - 0.25 mEq/L x ΔPCO2 | [HCO3-] = 18 mEq/L |
| Chronic: Δ[HCO3-] = - 0.4 to 0.5 mEq/L x ΔPCO2 | [HCO3-] = 15 mEq/L | |
| Metabolic acidosis | PCO2 = 1.5 x [HCO3-] + 8 ± 2 (Winters' formula) PCO2 = 15 + [HCO3-] PCO2 = last 2 digits of pH |
PCO2 = 15 mm Hg |
| Metabolic alkalosis | PCO2 = 0.6 x [HCO3-] PCO2 = 15 + [HCO3-] |
PCO2 = 55 mm Hg |