Whole Blood Lactate Kinetics in Patients Undergoing Quantitative Resuscitation for Severe Sepsis and Septic Shock

Background: We sought to compare the association of whole-blood lactate kinetics with survival in patients with septic shock undergoing early quantitative resuscitation. Methods: This was a preplanned analysis of a multicenter, ED-based, randomized, controlled trial of early sepsis resuscitation. Inclusion criteria were suspected infection, two or more systemic inflammation criteria, either systolic BP< 90 mm Hg after a fluid bolus or lactate level >4 mM, two serial lactate measurements, and an initial lactate level >2.0 mM. We calculated the relative lactate clearance, rate of lactate clearance, and occurrence of early lactate normalization (decline to <2.0 mM in the first 6 h). Area under the receiver operating characteristic curve (AUC) and multivariate logistic regression were used to determine the lactate kinetic parameters that were the strongest predictors of survival. Results: The analysis included 187 patients, of whom 36% (n = 68) normalized their lactate level. Overall survival was 76.5% (143 of 187 patients), and the AUC of initial lactate to predict survival was 0.64. The AUCs for relative lactate clearance and lactate clearance rate were 0.67 and 0.58, respectively. Lactate normalization was the strongest predictor of survival (adjusted OR, 5.2; 95% CI, 1.7-15.8), followed by lactate clearance >= 50% (OR, 4.0; 95% CI, 1.6-10.0). Lactate clearance >= 10% (OR, 1.6; 95% CI, 0.6-4.4) was not a significant independent predictor in this cohort. Conclusions: In patients in the ED with a sepsis diagnosis, early lactate normalization during the first 6 h of resuscitation was the strongest independent predictor of survival and was superior to other measures of lactate kinetics.