Aim: Screening and initial resuscitation are key aspects of sepsis guidelines, with lactate levels being central to discussions on sepsis management. We aimed to elucidate the relationship between mortality and lactate levels in septic shock patients and to evaluate the efficacy of static lactate levels versus lactate kinetics at specific time points.

Study Design: This retrospective cohort study was based on the archived records of patients admitted to the intensive care unit (ICU) from July 2019 to December 2019. Serum lactate levels were measured at ICU admission, and after 2, 6, 12, 24, and 48 hours.

Results: During the six-month study period, 90 patients managed in the intensive care unit and diagnosed with septic shock met the eligibility criteria. Lactate levels at admission and six hours later did not differ between the nonsurvivor and survivor groups (2.8 mmol/L vs. 2.42 mmol/L and 3.38 mmol/L vs. 2.61 mmol/L, respectively). Lactate levels at 2, 12, 24, and 48 hours after admission were higher in the nonsurvivor group, and the differences were statistically significant. Delta lactate levels at all time points did not differ between groups statistically. The analysis of the Receiver Operating Characteristic (ROC) curve for 28-day mortality showed that the lactate level at 48 hours had the best predictive value, with an Area Under the Curve (AUC) of 0.728.

Conclusions: Our study showed that in septic shock patients, lactate levels at a relatively late stage—48 hours after admission—could be utilized as a prognostic marker. New advances in the management of septic shock shifted focus from resuscitation endpoints to microcirculation parameters. The lactate kinetics of patients with critical illnesses might be investigated according to disease classification in the future.