Prognostic value of early lactate clearance in patients with post-cardiac arrest syndrome

The current guidelines emphasize that early prognostication of outcome is an essential component of post-cardiac arrest care. Lactate has been studied as an indicator of critical illness severity. Several studies reported that initial lactate level obtained immediately after hospital arrival was an independent predictor of survival and neurological outcomes in patients with post-cardiac arrest syndrome (PCAS). Recent studies also described that serial lactate measurements in early after-hospital admission could be more useful than a single lactate measurement as a predictor of outcome in those patients. Thus, we conducted an ad hoc analysis of the prospective, multicenter observational study to test the hypothesis that early lactate reduction within 6 h after admission could be a prognostic factor for the outcomes in PCAS. Among the eligible patients (n = 1482), the overall 30-day proportions for survival and good neurological outcome were 29.7% and 16.7%, respectively. Among the study patients, there were significant differences in age, ROSC prior to hospital arrival, epinephrine usage during ACLS, mechanical circulatory support, therapeutic hypothermia, and lactate levels at 0 and 6 h among the lactate clearance quartiles. Of note, patients in the quartile 4 group had the highest initial lactate level. Multivariate logistic regression analyses showed that lactate clearance quartile was an independent predictor of the 30-day survival and good neurologic outcome. In the Cox proportional hazards model, the frequency of mortality during 30 days was markedly higher for patients with lactate clearance in the 1st (hazard ratio, 3.12; 95% CI, 2.14-4.53), 2nd (2.13; 1.46-3.11), and 3rd quartile (1.49; 1.01-2.19) than those in the 4th quartile. In summary, effective lactate reduction over the first 6 h of post-cardiac arrest care was associated with survival and good neurologic outcome independent of the initial lactate level.