Hyperlactatemia is an independent predictor of mortality and denotes distinct subtypes of severe sepsis and septic shock

Abstract

Purpose: Current guidelines and most trials do not consider elevated lactate (Lac) serum concentrations when grading sepsis severity. We therefore assessed the association of different types of circulatory dysfunction regarding presence of hyperlactatemia and need for vasopressor support with clinical presentation and outcome of sepsis.

Methods: In a secondary analysis of a prospective observational multicenter cohort study, 988 patients with severe sepsis were investigated regarding vasopressor support, Lac levels, and outcome.

Results: Twenty-eight-day mortality regarding shock or hyperlactatemia was as follows: hyperlactatemia more than 2.5 mmol/L and septic shock (tissue dysoxic shock): 451 patients with a mortality of 44.8%; hyperlactatemia without vasopressor need (cryptic shock): 72 patients, mortality 35.3%; no hyperlactatemia with vasopressor need (vasoplegic shock): 331 patients, mortality 27.7%; and absence of hyperlactemia or overt shock (severe sepsis): 134 patients, mortality 14.2% (P < .001). These groups showed differences in source and origin of infection. The influence of hyperlactatemia on 28-day mortality (P < .001) (odds ratio 3.0, 95% confidence interval 2.1-4.1 for Lac >4 mmol/L) was independent of vasopressor support (P < .001) (odds ratio 2.0, 95% confidence interval 1.3-3.0 for norepinephrine >0.1 μg/kg per minute) in logistic regression.

Conclusions: Hyperlactatemia increases risk of death independent of vasopressor need resulting in different phenotypes within the classic categories of severe sepsis and septic shock.

Keywords: Critical care; Lactic acid; Sepsis; Septic shock.