Elsevier

Resuscitation

Volume 90, May 2015, Pages 127-132
Resuscitation

Clinical Paper
Malignant EEG patterns in cardiac arrest patients treated with targeted temperature management who survive to hospital discharge

https://doi.org/10.1016/j.resuscitation.2015.03.005Get rights and content

Abstract

Background and purpose

Cardiac arrest patients treated with targeted temperature management (TTM) have improved neurological outcomes, however mortality remains high. EEG monitoring improves detection of malignant EEG patterns (MEPs), however their prevalence in patients surviving to hospital discharge is unknown.

Design/methods

We examined consecutive cardiac arrest subjects who received TTM and continuous EEG monitoring at one academic center. Only subjects surviving to hospital discharge were included in the analysis. MEPs were defined as seizures, status epilepticus, myoclonic status epilepticus, or generalized periodic discharges. Subjects with suppression-burst (SB) without concomitant MEPs were categorized as having a “pure” SB pattern. Demographic, survival, hospital discharge disposition, and neurological function data were recorded retrospectively. Outcomes were assessed using the Glasgow-Pittsburgh Cerebral Performance Category (CPC). A CPC score of 1–2 was considered “good” neurological function, and a CPC of 3–4 “poor”.

Results

Of 364 admissions due to cardiac arrest screened, 120 (29.9%) survived to hospital discharge and met inclusion criteria. MEPs and pure SB were observed in 19 (15.8%) and 22 (18.3%) survivors respectively. Two subjects with MEP and eight subjects with pure SB had good neurological function at discharge, however all SB cases were confounded by the use of anesthetic agents. Presence of MEPs was not an independent predictor of poor neurological function (p = 0.1).

Conclusions

MEPs are common among cardiac arrest patients treated with induced hypothermia who survive to hospital discharge. Poor neurological function at discharge was not associated with MEPs. Prospective studies assessing the role of EEG monitoring in cardiac arrest prognostication are warranted.

Introduction

Mild induced hypothermia (IH) became a major therapy for out-of-hospital cardiac arrest (OHCA) attributable to ventricular fibrillation after 2002, and its application expanded to non-shockable rhythms.1, 2 Recent data demonstrate similar outcomes between IH and targeted temperature management (TTM) of 36 °C in the out of hospital VF/VT population.3 Despite the increased survival rates and improved long-term neurological function shown in randomized controlled trials with TTM, identifying which comatose patients will have a favorable outcome remains challenging.1, 2, 4, 5

Malignant EEG patterns (MEPs) such as seizures, status epilepticus (SE), and suppression-burst (SB) are considered predictors of poor neurological function in cardiac arrest.6, 7, 8, 9, 10 For this reason, the American Heart Association guidelines and the American Academy of Neurology practice parameters for prognostication in cardiac arrest consider EEG monitoring a helpful tool for cardiac arrest prognostication.2, 7, 10 However, the prognostic value of EEG monitoring when TTM is utilized has been challenged more recently, as reports of good neurological function despite the presence of MEP have emerged.11

The aim of this study was to identify the incidence of MEPs, SB, and other relevant EEG features in cardiac arrest patients treated with TTM who survive to hospital discharge.

Section snippets

Subjects

All consecutive adult subjects (≥18 years) admitted to a single tertiary care center after being successfully resuscitated from either in-hospital or out-of-hospital cardiac arrest were prospectively enrolled in a quality improvement database from 08/28/2009 to 06/04/2013. Only subjects undergoing IH for cardiac arrest who survived to hospital discharge and had more than 10 h of continuous EEG monitoring were included in this study.

Hypothermia protocol

In our institution, subjects that remain comatose after return

Results

Medical charts from 364 consecutive admissions of 362 subjects presenting with cardiac arrest were screened. Two subjects were admitted after cardiac arrest in two different occasions, and in both cases did not survive the second admission. Subjects who did not survive to hospital discharge (239 subjects), or those who had insufficient EEG monitoring (five subjects) were excluded from the final analysis. Insufficient EEG monitoring occurred due to early clinical improvement in two subjects who

Discussion

In this study, we demonstrated that MEPs and pure SB are commonly seen in cardiac arrest subjects who survive to hospital discharge. Moreover, the presence of MEPs was not correlated with functional outcome. Several subjects with MEPs were discharged to home or rehabilitation, including two subjects with myoclonic status epilepticus.

Epileptiform activity is prevalent in cardiac arrest patients treated with TTM, and these EEG findings are associated with high in-hospital mortality and poor

Conclusion

MEPs and pure SB are common features in EEG recordings of cardiac arrest patients treated with TTM who survive to hospital discharge. The fact that MEPs were not uniformly associated with unfavorable outcomes suggests that EEG data should be interpreted with caution and integrated with a multimodal approach to prognostication. Prospective studies including long-term outcomes are needed to evaluate the role of prolonged EEG monitoring in prognostication of cardiac arrest subjects treated with

Conflict of interest statement

The authors have no conflict of interest to report.

Acknowledgements

The authors thank the Continuous EEG Service and the UPMC Presbyterian Hospital EEG laboratory for their support to this project. We also thank Mr. Yin Zhao for data abstraction. This publication was supported by the National Institutes of Health through Grant Number UL1-TR-000005.

References (39)

  • J.M. Lucas et al.

    Neurologic recovery after therapeutic hypothermia in patients with post-cardiac arrest myoclonus

    Resuscitation

    (2012)
  • S. Legriel et al.

    Prognostic value of electrographic postanoxic status epilepticus in comatose cardiac-arrest survivors in the therapeutic hypothermia era

    Resuscitation

    (2013)
  • V. Alvarez et al.

    Stimulus-induced rhythmic, periodic or ictal discharges (SIRPIDs) in comatose survivors of cardiac arrest: characteristics and prognostic value

    Clin Neurophysiol: Offi J Int Fed Clin Neurophysiol

    (2013)
  • R. Mani et al.

    The frequency and timing of epileptiform activity on continuous electroencephalogram in comatose post-cardiac arrest syndrome patients treated with therapeutic hypothermia

    Resuscitation

    (2012)
  • K.D. Raina et al.

    Neurological and functional status following cardiac arrest: method and tool utility

    Resuscitation

    (2008)
  • Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest

    New Engl J Med

    (2002)
  • M.A. Peberdy et al.

    Part 9: post-cardiac arrest care: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

    Circulation

    (2010)
  • N. Nielsen et al.

    Targeted temperature management at 33 degrees C versus 36 degrees C after cardiac arrest

    New Engl J Med

    (2013)
  • S.A. Bernard et al.

    Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia

    New Engl J Med

    (2002)
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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.2009.04.030.

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