Limited Prognostic Value of 12-Hour Lactate Clearance After Cardiac Arrest: A Retrospective Observational Study

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Sait Fatih Öner, Sevim Şenol Karataş, Oğuz Kağan Bulut

Volume 9 · Issue 2 · pp. 355–360

Published: 2026-06-30

Abstract

Purpose: This study aimed to evaluate the association between 12-hour lactate clearance and mortality in adult patients who achieved return of spontaneous circulation (ROSC) after cardiopulmonary arrest and were monitored in the intensive care unit. Methods: This retrospective study included adult patients admitted to the intensive care unit after cardiopulmonary arrest between January 2023 and January 2025. Lactate clearance was calculated in patients with available baseline and 12-hour lactate measurements. Patients who died within the first 12 hours were included in early mortality analyses but excluded from lactate clearance analyses. The predictive value of baseline lactate was assessed using ROC analysis, and multivariable logistic regression analysis was performed in patients with calculable lactate clearance. Results: A total of 229 patients were included. During ICU stay, 180 patients (78.6%) died, including 52 who died within the first 12 hours. Baseline lactate levels were markedly elevated in patients who died within the first 12 hours (median 14.1 mmol/L; IQR 9.9–16.0). Mortality was 79.5% in patients with negative lactate clearance and 69.9% in those with positive clearance. Lactate clearance was not independently associated with mortality. Baseline lactate demonstrated good predictive performance for 12-hour mortality (AUC = 0.75) and moderate performance for ICU mortality (AUC = 0.69). Conclusion: Admission lactate levels were effective predictors of early mortality, whereas lactate clearance was not independently associated with mortality.

Keywords: Cardiopulmonary arrest; Lactate clearance; Mortality; Intensive care

1. Introduction

Cardiopulmonary arrest (CPA) is a serious clinical condition associated with high mortality and morbidity. Although return of spontaneous circulation (ROSC) can be achieved in some patients, a substantial proportion die during the intensive care process or develop permanent neurological sequelae1,2. There is a substantial need to identify reliable prognostic markers that can support clinical decision-making during the post-ROSC period.

Serum lactate is commonly used as a marker of tissue hypoperfusion and anaerobic metabolism3. Previous studies have reported a clear association between elevated lactate concentrations and increased mortality following cardiac arrest4,5. Nevertheless, reliance on a single lactate measurement has been questioned, as it may fail to capture the dynamic metabolic changes occurring after resuscitation6. For this reason, lactate clearance has been proposed as an alternative prognostic measure. In septic patients, improvements in lactate clearance have been linked to better survival outcomes7,8.

The prognostic significance of lactate clearance following cardiopulmonary arrest continues to be debated. Although certain studies suggest early reductions in lactate are associated with improved survival9, others indicate that lactate clearance assessed at later intervals provides limited prognostic information10. Further studies employing clearly defined assessment intervals and direct comparisons between lactate clearance and admission lactate levels are still warranted11.

2. Materials and Methods

This study was conducted by retrospectively reviewing data from patients who achieved ROSC after cardiopulmonary arrest and were followed in the intensive care unit between January 2023 and January 2025. All eligible patients during the study period were consecutively included.

Patients aged 18 years and older admitted to the ICU after achieving ROSC following cardiopulmonary arrest were included. Patients younger than 18 years and those with unavailable essential clinical or laboratory data were excluded.

Of the 229 patients included, 52 died within the first 12 hours and could not undergo serial lactate measurements; therefore, they were excluded from lactate clearance analyses but included in early mortality analyses. The final study population for lactate clearance analyses consisted of 177 patients.

Serum lactate levels were recorded at ICU admission (0 hour) and at the 12th hour. Lactate clearance was calculated as: (baseline lactate level − 12-hour lactate level) / baseline lactate level × 100. Patients were classified into positive and negative lactate clearance groups. Admission lactate levels were used in ROC analyses to assess their predictive value for mortality.

Statistical Analysis

Data distribution was assessed using the Shapiro–Wilk test. Normally distributed data are presented as mean ± SD; non-normally distributed data as median (IQR). Group comparisons used the Student’s t-test, Mann–Whitney U test, one-way ANOVA, or Kruskal–Wallis test as appropriate. Categorical variables were compared using the chi-square test. Multivariable logistic regression included lactate clearance (per 10% decrease), age, and CPR duration. ROC analysis was performed with AUC estimated using 2,000-iteration bootstrap resampling. Optimal thresholds were identified using the Youden index. A two-tailed p < 0.05 was considered statistically significant.

Ethics Approval

Ethical approval was obtained from the Clinical Research Ethics Committee of Elazig Fethi Sekin City Hospital (18 September 2025; Decision No: 2025/15-11). The study was conducted in accordance with the Declaration of Helsinki and reported in compliance with the STROBE guidelines. Due to the retrospective design, the requirement for informed consent was waived.

3. Results

A total of 229 patients were included. Of these, 180 (78.6%) died during their ICU stay, while 49 (21.4%) were discharged alive. Patients who died were older and had a longer CPR duration compared with survivors; however, these differences did not reach statistical significance (Table 1).

Table 1. Baseline characteristics of the study population according to clinical outcome

Table 1

Variable Non-survivors (n=180) Survivors (n=49) p value
Age, years 74.0 (65.0–83.0) 70.0 (53.0–80.0) 0.0876
CPR duration, min 20.0 (15.0–30.0) 20.0 (12.0–22.0) 0.0898
Sex (Female/Male) 85/95 17/32 0.1608

Continuous variables are presented as median (IQR). Categorical variables as counts. Group comparisons used the Mann–Whitney U test or chi-square test.

Among the 229 patients, 52 died within the first 12 hours after ICU admission. Lactate clearance could be calculated in 177 patients. Among these, 44 had negative and 133 had positive lactate clearance. Mortality was 79.5% in the negative clearance group and 69.9% in the positive clearance group. Admission lactate levels were highest in the early mortality group (Table 2).

Table 2. Clinical outcomes and admission lactate according to early mortality and lactate clearance groups

Table 2

Group n Mortality n (%) Admission lactate median (IQR) mmol/L
≤12-hour mortality 52 52 (100.0%) 14.1 (9.9–16.0)
Negative lactate clearance 44 35 (79.5%) 4.9 (2.0–13.0)
Positive lactate clearance 133 93 (69.9%) 7.9 (4.4–11.3)

In multivariable logistic regression analysis, lactate clearance was not independently associated with mortality (OR per 10% decrease 1.012; 95% CI 0.969–1.057; p = 0.595). Age and CPR duration were also not identified as independent predictors (Table 3).

Table 3. Multivariable logistic regression analysis of factors associated with mortality

Table 3

Variable OR 95% CI Lower 95% CI Upper p value
Lactate clearance (per 10% decrease) 1.012 0.969 1.057 0.595
Age 1.018 0.997 1.040 0.097
CPR duration, min 1.023 0.993 1.054 0.132

Lactate clearance entered as continuous variable scaled per 10% decrease. Analysis restricted to patients with calculable lactate clearance. OR: odds ratio; CI: confidence interval.

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Cite this article

Sait Fatih Öner, Sevim Şenol Karataş, Oğuz Kağan Bulut. Limited Prognostic Value of 12-Hour Lactate Clearance After Cardiac Arrest: A Retrospective Observational Study. Journal of Cukurova Anesthesia and Surgical Sciences. 9(2):355-360. https://doi.org/10.36516/jocass.1884814

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