Early Lactate Values After Out-of-Hospital Cardiac Arrest: Associations with One-Year Outcome.

Background: Previous studies have shown associations between high admission serum lactate, lower lactate clearance, and increased short-term mortality after out-hospital cardiac arrest (OHCA). We studied whether lactate levels predict long-term outcome after OHCA. Methods: We included 458 OHCA patients with lactate measurements during intensive care unit (ICU) stay from the prospective FINNRESUSCI study. We evaluated thresholds for time-weighted (TW) mean lactate values for the first 24, 48, and 72 h. We analyzed lactate clearance and used multivariate regression to assess the prognostic value of the different measurement time points. Results: The admission lactate (median [IQR] 3.06 [2.68-3.44] mmol/L vs 4.76 [4.29-5.23] mmol/L) and the last measured lactate (0.98 [0.90-1.06] mmol/L vs 2.40 [2.032.78] mmol/L) were higher in non-survivors than in survivors, as were the lowest (0.73 [0.67-0.79] mmol/L vs 1.83 [1.522.14] mmol/L) and the highest (3.44 [3.05-3.83] mmol/L vs 5.25 [4.76-5.74] mmol/L) lactate values (all P<0.001). Timeweighted mean lactate values for the first 24, 48, 72, and for the entire ICU stay were lower in patients with good outcome (P<0.001). In multivariate backward regression models, time-weighted mean lactate for the entire ICU stay (OR 1.41 per mmol/L, CI 95% 1.08-1.86, P = 0.013) and the last measured lactate in the ICU (OR 2.16 per mmol/L, CI 95% 1.47-3.18, P<0.001) were independent predictors of poor 1-year outcome. Conclusions: In the present study time-weighted mean lactate values for the entire ICU stay, and the last measured lactate value in the ICU, but not admission lactate or lactate clearance were independent predictors of poor 1-year outcome.