RESUMO
Metabolic acid-base disorders are comnom clinical problems in ICU patients. Arterial blood gas analysis and anion gap (AG) are important laboratory data in approaching acid-base interpretation. When measuring the AG, several factors such as albumin have influence on unmeasured anions and unmeasured cations. If a patient has hypoalbuminemia, the AG should be adjusted according to the albumin level. High AG metabolic acidoses including lactic acidosis, ketoacidosis, and ingestion of toxic alcohols are common in ICU patients. The treatment target of lactic acidosis and ketoacidosis is not the acidosis, but the underlying condition causing acidosis. Gastric acid loss, diuretics, volume depletion, renal compensation for respiratory acidosis, hypokalemia, and mineralocorticoid excess are common causes of metaboic alkalosis. In chloride responsive metaboic alkalosis, volume and potassium repletion are mandatory.