Diagnostic accuracy of lactate levels after initial fluid resuscitation as a predictor for 28 day mortality in septic shock

Abstract

Purpose: The aim of the study was to investigate the diagnostic accuracy of initial and post-fluid resuscitation lactate levels in predicting 28 day mortality.

Materials and methods: We retrospectively analyzed a multi-center registry of suspected septic shock cases that was prospectively collected between October 2015 and December 2018 from 11 Emergency Departments. The primary outcome was 28 day mortality. The diagnostic performance of the initial and post-fluid resuscitation lactate levels as a predictor for 28 day mortality was assessed.

Results: A total of 2568 patients were included in the final analysis. The overall 28 day mortality rate was 23%. The area under the receiver operating characteristic curve (AUROC) of initial lactate for predicting 28 day mortality was 0.66 (95% CI, 0.64-0.69) and that of after fluid administration lactate was 0.70 (95% CI, 0.67-0.72), and there was a significant difference (p < 0.001). The optimal cutoff point of lactate after fluid administration was 4.4 mmol/L. Compared with this, the Sepsis-3 definition with a lactate level of 2 mmol/L or more was relatively more sensitive and less specific for predicting 28 day mortality.

Conclusion: The post-fluid resuscitation lactate level was more accurate than the initial lactate level in predicting 28 day mortality in patients with suspected septic shock.

Keywords: Fluid resuscitation; Lactate; Outcomes; Sepsis; Septic shock; Septic shock definition.