Effects of Initial Lactate Levels and 24-h Lactate Clearance on Mortality in Post-Cardiac Arrest Patients: Insights from the Multicenter TIMECARD Registry.

Abstract

Background: Lactate concentration and clearance are critical indicators of systemic hypoperfusion and can predict post-cardiac arrest outcomes. However, their combined prognostic value and factors influencing clearance achievement remain unexplored.

Methods: This retrospective study analyzed 1,016 adults with cardiac arrest from the Taiwan TIMECARD registry (January 2017-July 2024) who achieved return of spontaneous circulation (ROSC). Patients were stratified into quartiles based on initial lactate levels and 24-hour lactate clearance, defined as the percentage reduction in serum lactate from ROSC to 24 hours. Cox proportional hazards models were used to assess associations with 3-day and 30-day all-cause mortality following ROSC.

Results: Higher initial lactate levels (≥12.3 mmol/L) were associated with increased risks of 3-day (hazard ratio [HR]: 3.42, 95% confidence interval [CI]: 1.88-6.22) and 30-day mortality (HR: 1.88, 95% CI: 1.44-2.46). Poor lactate clearance (<16%) was associated with increased 3-day (HR: 21.05, 95% CI: 9.19-48.22) and 30-day mortality (HR: 2.74, 95% CI: 2.13-3.53). Patients achieving rapid clearance had better mortality outcomes despite moderately elevated initial levels, whereas those with both high initial lactate and poor clearance had a 6.9-fold higher 30-day mortality risk. Factors associated with low clearance included age ≥65 years, INR ≥1.15, Glasgow Coma Scale score ≤8, systolic blood pressure ≤125 mmHg, and repeat cardiopulmonary resuscitation within 1 h; conversely, targeted temperature management was protective.

Conclusion: Routine measurement of lactate levels at ROSC, together with serial monitoring after cardiac arrest, provides clinically meaningful prognostic information. Although initial lactate levels reflect disease severity, their prognostic impact may be modifiable through adequate clearance, whereas poor clearance is associated with an increased risk of mortality. Early identification of patients with inadequate clearance may facilitate targeted interventions to improve survival.