To evaluate the relative importance of increased
lactate production as opposed to decreased utilization in hyperlactatemic patients, as well as their relation to
glucose metabolism.
DESIGN: Prospective observational study.
SETTING: Baseline arterial
lactate was higher in septic (3.2 +/- 2.6) and
cardiogenic shock patients (2.8 +/- 0.4) than in healthy volunteers (0.9 +/- 0.20 mmol/L, p < .05).
Lactate clearance, computed using pharmacokinetic calculations, was similar in septic,
cardiogenic shock, and controls, respectively: 10.8 +/- 5.4, 9.6 +/- 2.1, and 12.0 +/- 2.6 mL/kg/min. Endogenous
lactate production was determined as the initial
lactate concentration multiplied by
lactate clearance. It was markedly enhanced in the patients (septic 26.2 +/- 10.5;
cardiogenic shock 26.6 +/- 5.1) compared with controls (11.2 +/- 2.7 micromol/kg/min, p < .01). C-
lactate oxidation (septic 54 +/- 25;
cardiogenic shock 43 +/- 16; controls 65 +/- 15% of a
lactate load of 10 micromol/kg/min) and transformation of C-
lactate into C-
glucose were not different (respectively, 15 +/- 15, 9 +/- 18, and 10 +/- 7%). Endogenous
glucose production was markedly increased in the patients (septic 14.8 +/- 1.8;
cardiogenic shock 15.0 +/- 1.5) compared with controls (7.2 +/- 1.1 micromol/kg/min, p < .01) and was not influenced by
lactate infusion.
CONCLUSIONS: