Correlation between initial serum levels of lactate after return of spontaneous circulation and survival and neurological outcomes in patients who undergo therapeutic hypothermia after cardiac arrest

Objectives: We analysed the relationship between serum levels of lactate within 1. h of return of spontaneous circulation (ROSC) and survival and neurological outcomes in patients who underwent therapeutic hypothermia (TH). Methods: This was a multi-centre retrospective and observational study that examined data from the first Korean Hypothermia Network (KORHN) registry from 2007 to 2012. The inclusion criteria were out-of-hospital cardiac arrest (OHCA) and examination of serum levels of lactate within 1. h after ROSC, taken from KORHN registry data. The primary endpoint was survival outcome at hospital discharge, and the secondary endpoint was poor neurological outcome (Cerebral Performance Category, CPC, 3-5) at hospital discharge. Initial lactate levels and other variables collected within 1. h of ROSC were analysed via multivariable logistic regression. Results: Data from 930 cardiac arrest patients who underwent TH were collected from the KORHN registry. In a total of 443 patients, serum levels of lactate were examined within 1. h of ROSC. In-hospital mortality was 289/443 (65.24%), and 347/443 (78.33%) of the patients had CPCs of 3-5 upon hospital discharge. The odds ratios of lactate levels for CPC and in-hospital mortality were 1.072 (95% confidence interval (CI) 1.026-1.121) and 1.087 (95% CI. =. 1.031-1.147), respectively, based on multivariate ordinal logistic regression analyses. Conclusion: High levels of lactate in serum measured within 1. h of ROSC are associated with hospital mortality and high CPC scores in cardiac arrest patients treated with TH.