Severe perioperative lactic acidosis: how clinically significant is it?

BACKGROUND: Lactic acidosis, generally defined as a plasma lactate concentration in excess of 5 mmol/L with a concomitant blood pH less than 7.25, is reported to have a direct association with mortality. OBJECTIVE: To report a case of unexplained perioperative lactic acidosis and to discuss the etiology, recognition, treatment, and importance of a transient rise in plasma lactate concentration. SUMMARY: Severe lactic acidosis developed in a 40-year-old man with Crohn's disease during major abdominal surgery. The plasma lactate concentration reached 16.9 mmol/L (normal range 1.5 to 2.2 mmol/L). This condition resolved within 14 hours without harm to the patient. CONCLUSIONS: When lactate accumulates in the perioperative period, the responsible condition is most often self-limiting. Reversible, subacute, marked lactic acidosis should not be assumed to predict mortality as it does in patients whose plasma lactate concentrations remain chronically elevated during severe systemic diseases such as sepsis.