Elsevier

Resuscitation

Volume 88, March 2015, Pages 143-149
Resuscitation

Clinical paper
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

https://doi.org/10.1016/j.resuscitation.2014.11.005Get rights and content

Abstract

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.

Introduction

Therapeutic hypothermia (TH) has improved the survival and neurological outcomes of patients who survive cardiac arrest 1, 2. The therapy is commonly used for comatose survivors with cardiac arrest as part of a series of survival treatments for cardiopulmonary resuscitation 3. During TH, physicians need to be aware of the neurological and survival outcomes of comatose patients. Thus, several studies have been performed to develop tools to predict the neurological prognosis and survival outcomes. However, no single effective method for the prediction of outcome has been found. Several biological markers, such as the S-100B protein and neuron-specific enolase, have been demonstrated to be useful, and electroencephalography and neuroimaging, including brain computed tomography and magnetic resonance imaging, have been used by physicians to predict neurological outcomes 4, 5, 6, 7, 8, 9, 10, 11, 12. However, these methods require serial check-ups and longer times to determine results.

An effective method for predicting survival and neurological outcomes that can be applied early on in the treatment process would be useful for planning treatment strategies for post-cardiac arrest care. However, there is a lack of objective data on such patients collected within 1 h after return of spontaneous circulation (ROSC) in the emergency department (ED). Such data would comprise pre-hospital data, including data from emergency medical service (EMS); initial laboratory findings taken after ROSC; and the results of physical and neurological examinations performed in the ED. Serum lactate levels are one of these initial laboratory findings. Early and effective clearance of serum lactate (i.e., lower levels) are associated with lower mortality in patients with many critical illnesses, including sepsis and severe trauma 13, 14, 15, 16, 17, 18. For cardiac arrest survivors, the relationships between clearance of serum lactate and neurological and survival outcomes have been studied 19, 20, 21, 22, 23. However, few studies have addressed the potential relationship between initial serum levels of lactate and outcomes in patients who have been treated with TH. Thus, in this study, we evaluated whether initial levels of lactate in the serum at ROSC were correlated with neurological and survival outcomes of patients undergoing TH.

Section snippets

Registry data collection

This was a multi-centre, retrospective, observational, registry-based study that used data from the first Korean Hypothermia Network (KORHN) registry. KORHN, a multi-centre clinical research consortium for TH in South Korea, was organised in 2011, and a multi-centre retrospective, registry project was performed in 2012. The KORHN investigators collected data regarding post-cardiac arrest TH in 24 teaching hospitals around South Korea from 2007 to 2012. The institutional review board of each

Results

Data on 930 cardiac arrest patients with TH were collected from the KORHN registry; 443 patients who met the inclusion criteria were enrolled. Of these patients, 14 arrived at the ED with ROSC, and 429 patients were resuscitated at the ED. The general characteristics of these patients are listed in Table 1 according to hospital mortality and neurological outcomes at hospital discharge. The mean age of the patients was 57.70 ± 16.06 years. There were 295 (66.6%) males and 148 (33.4%) females. The

Discussion

In resuscitated patients from OHCA undergoing TH, initial serum levels of lactate within 1 h after ROSC were associated with survival and neurological outcomes at hospital discharge (Table 3). Many investigators have sought to develop effective tools that can predict survival and neurological outcomes in post-cardiac arrest patients. Thus, many biomarkers, brain imaging methods, and neurophysiological examinations have been studied as prognostic tools. However, these techniques are limited in

Limitations

This study had several limitations. First, it was a retrospective analysis; thus, although TH was performed in all of the involved patients, the method of TH and treatment protocol were not standardised. Second, we used pre-hospital time as variable for pre-hospital resuscitation time, whereas most prior studies have used no-flow time and low-flow time, per EMS records. However, in the present study, we could not divide the data according to no-flow time and low-flow time from EMS. Thus, the

Conclusions

Serum levels of lactate within 1 h after ROSC are associated with hospital mortality and high CPC scores in cardiac arrest patients treated with TH. Although elevated levels of lactate cannot be presumed to be a direct parameter of patient neurological or survival outcomes, these results may be useful for establishing treatment plans in the early stages after ROSC.

Conflict of interest statement

None declared.

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  • Cited by (54)

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    A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2014.11.005.

    1

    Department of Emergency Medicine, Chung-Ang University Hospital, 224-1 Heoukseok-dong, Dongjak-gu, Seoul, Republic of Korea

    2

    Department of Emergency Medicine, Ewha Womans University Medical center 911-1 Mok-dong, Yang chun-Gu, Republic of Korea

    3

    Department of Emergency Medicine, Chonnam National University Hospital, 42 Jebong-ro, Dong-gu, Gwangju, Republic of Korea

    4

    Department of Emergency Medicine, College of Medicine Chungbuk National University Hospital, Gaesin-dong, Heungdeok-gu, Cheongju-si, Chungbuk, Republic of Korea

    5

    Emergency Medicine, Seoul St. Mary's hospital, 222 Banpo-daero, Seocho-Gu, Seoul, Republic of Korea

    6

    Department of Emergency Medicine, Hallym University Sacred Heart Hospital, Hallym University Medical Center, 896 Pyeongchon-dong, Dongan-gu, Anyang-si, Gyeonggi-do, Republic of Korea

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