[Metabolic alkalosis despite hyperlactatemia and hypercapnia. Interpretation and therapy with help of the Stewart concept].

Acid-base disturbances are commonly found in critically ill patients and are often associated with fatal complications. The basis of a successful treatment is a thorough understanding of the causes of these disorders. The "classical methods" to explain acid-base disorders--pH, base excess and bicarbonate concentration--mostly do not provide a causal correlation to the underlying pathology. An unusual case of a combined respiratory-metabolic disorder with hyperlactatemia and hypercapnia is presented. An acidosis masked by hypochloremic and hypoalbuminemic alkalosis was identified with the help of Stewart's concept and finally permitted a successful therapy. The modern Stewart concept provides enhanced information, enabling an exact diagnosis and causal therapy even in complex cases.