Temporal Changes of Lactate in CLASSIC Patients

This is a retrospective analysis of a subset of patients included in the Conservative versus Liberal Approach to fluid therapy of Septic Shock in Intensive Care (CLASSIC) trial.

In the CLASSIC trial patients with septic shock were randomized to either traditional (liberal) strategy for fluid treatment or a more conservative regimen. The study was an international multicenter clinical trial (clinicaltrials.gov NCT03668236), and results were published in New England Journal of Medicine in June 2022 (DOI: 10.1056/NEJMoa2202707).

In this substudy the investigator extract all lactate values for the study period from all patients included from Karolinska University Hospital, Sundsvall and Södersjukhuset (Sweden), participating centers on Zealand (Denmark), and Plzen University Hospital (Czech Republic). Baseline data, treatment allocation and amount of fluids administered are collected as well as outcome from CLASSIC study.

Primary outcome is time to lactate normalization (< 2mmol/L). Secondary outcome is lactate concentration over the first 72 hours (as peak lactate for the time intervals 0-3, 3-6, 6-12, 12-24 and then each 12h-period between 24 and 72 hours).

The subgroup with blood lactate > 4mmol/L will be analyzed separately for the same end points.

Time to resolution of hyperlactatemia will be modelled with a competing risks regression. Death and discharge will be competing outcomes, and administrative censoring imposed 72 hours after randomisation.

Factors associated with time to lactate normalization will be examined through regression analysis. Factors that show a relationship on univariate analysis will be included in a multivariate analysis.

Inclusion criteria

• Participation in CLASSIC trial in any of the participating centres

Exclusion criteria

• Lack of sufficient data for analysis