Controversies in lactic acidosis. Implications in critically ill patients.

Lactic acidosis is common in critically ill patients and is usually caused by tissue perfusion that is inadequate to meet metabolic demand. However, it has also been noted in conditions in which tissue perfusion is apparently adequate. Hyperlactatemia can occur in the absence of acidosis, usually in the setting of hypermetabolic disease. Numerous areas of controversy exist regarding the pathogenesis of lactic acidosis, as well as certain of its diagnostic, therapeutic, and prognostic features. Knowledge of these areas of controversy should facilitate the clinician's approach to diagnosis and management.