Objective:The purpose of this study was to investigate the prognostic value of lactate at admission, 12-hour lactate and 12-hour lactate clearance for 30-day survival in comatose patients admitted after out of hospital cardiac Arrest(OHCA).

Background:Although measures of lactate have been successfully implemented in sepsis and trauma care, most OHCA studies are biased due to design and the results are conflicting. 

Design:This is a post hoc analysis of the TTM-Trial, a multicentre randomized controlled trial investigating a temperature intervention of 33 C vs 36 C after OHCA.

Results:939 patients were analysed. 30-day survival was 56%. Median admission lactate was 6.0 mmol/l [3.0-9.5]. Survivors at day 30 had lower admission lactate 4.7 mmol/l [2.4-8.9] vs 7.3 mmol/l [4.5-10.7] for non-survivors, p<0.01. The difference in median 12-hour lactate was 1.4 mmol/l [1.0-2.3] vs 2.0 mmol/l [1.2-3.3], p<0.01. 12-hour lactate clearance was 47±70% in survivors vs 54±46%, p=0.03. In a mixed model including all sample times, average lactate values were higher in the 33C-group, p<0.001. In an unadjusted model the odds ratio(OR) for death by 1 mmol/l increase in lactate was 1.1[1.1-1.2] at admission (p<0.01), 1.2[1.1-1.3] at 12-hours (p<0.01) and 1.003 [1.0-1.01] per % decrease in 12-hour clearance , p=0.03). In a multivariate analysis, admission lactate and 12-hour lactate remained independent predictors of 30-day mortality. Area under the receiver operator characteristics curve was for Admission lactate=0.65, 12-h Lactate AUC=0.61, 12-h lactate clearance AUC= 0.53.

Conclusion:Admission lactate and 12-hour lactate are associated with 30-day survival after cardiac arrest. The diagnostic value of these lactate measures is of limited use in clinical praxis.

The prognostic performance of lactate in out of hospital cardiac arrest, a post hoc analysis of the TTM-trial