Metabolic acid-base status in critically ill patients: is standard base excess correlated with serum lactate level?

BACKGROUND AND OBJECTIVES To correlate standard base excess (SBE) with serum lactate level and demonstrate the independent prognostic significance of each one. METHODS In a retrospective study, we retrieved data from 333 patients of our prospectively collected database of 7-bed medical intensive care unit of a 1800-bed university hospital. RESULTS The results have shown a poor correlation between SBE and lactate, r = - 0.358, p < 0.001, and an independent prognostic significance of each one when analyzed concomitantly, odds ratio (95% Confidence interval) = 0.996 (0.992 - 0.999) to standard base excess and 1.000 (1.000 - 1.002) to lactate at entrance; and odds ratio (95% Confidence interval ) = 0.990 (0.985 - 0.994) to standard base excess and 1.003 (1.001 - 1.005) to lactate after 24 hours. The accuracy of standard base excess was close to lactate to determine in-intensive care unit death. CONCLUSIONS The lactic component of the metabolic acidosis is not the major determinant of standard base excess. Serum lactate and SBE are independent outcome predictors in critically ill patients.