Prognostic Value of Blood Lactate Levels: Does the Clinical Diagnosis at Admission Matter?
The Journal of Trauma: Injury, Infection, and Critical Care:Volume 66(2)February 2009pp 377-385
Hyperlactatemia and its reduction after admission in the intensive care unit (ICU) have been related to survival. Because it is unknown whether this equally applies to different groups of critically ill patients, we compared the prognostic value of repeated lactate levels (a) in septic patients versus patients with hemorrhage or other conditions generally associated with low-oxygen transport (LT) (b) in hemodynamically stable versus unstable patients.
In this prospective observational two-center study (n = 394 patients), blood lactate levels at admission to the ICU (LacT0) and the reduction of lactate levels from T = 0 to T = 12 hours (ΔLacT0-12) and from T = 12 to T = 24 hours (ΔLacT12-24), were related to in-hospital mortality.
Reduction of lactate was associated with a lower mortality only in the sepsis group (ΔLacT0-12: hazard ratio [HR] 0.34, p = 0.004 and ΔLacT12-24: HR 0.24, p = 0.003), but not in the LT group (ΔLacT0-12; HR 0.78, p = 0.52 and ΔLacT12-24; HR 1.30, p = 0.61). The prognostic values of LacT0, ΔLacT0-12, and ΔLacT12-24 were similar in hemodynamically stable and unstable patients (p = 0.43).
Regardless of the hemodynamic status, lactate reduction during the first 24 hours of ICU stay is associated with improved outcome only in septic patients, but not in patients with hemorrhage or other conditions generally associated with low-oxygen transport (LT). We hypothesize that in this particular group a reduction in lactate is not associated with improved outcome due to irreversible damage at ICU admission.