Elsevier

Resuscitation

Volume 84, Issue 3, March 2013, Pages 343-350
Resuscitation

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

https://doi.org/10.1016/j.resuscitation.2012.11.001Get rights and content

Abstract

Background

The independent prognostic significance of postanoxic status epilepticus (PSE) has not been evaluated prospectively since the introduction of therapeutic hypothermia. We studied 1-year functional outcomes and their determinants in comatose survivors of cardiac arrest (CA), with special attention to PSE.

Methods

106 comatose CA survivors admitted to the intensive care unit in 2005–2010 were included in a prospective observational study. The main outcome measure was a Cerebral Performance Category scale (CPC) of 1 or 2 (favorable outcome) 1 year after CA.

Results

CA occurred out-of-hospital in 89 (84%) patients and was witnessed from onset in 94 (89%). Median times were 6 min (IQR, 0–11) from CA to first-responder arrival and 23 min (14–40) from collapse to return of spontaneous circulation. PSE was diagnosed in 33 (31%) patients at a median of 39 h (4–49) after CA. PSE was refractory in 24 (22%) cases and malignant in 19 (20%). After 1 year, 31 (29.3%) patients had favorable outcomes including 2 (6.44%) with PSE. Factors independently associated with poor outcome (CPC  3) were PSE (odds ratio [OR], 14.28; 95% confidence interval [95% CI], 2.77–50.0; P = 0.001), time to restoration of spontaneous circulation (OR, 1.04/min; 95% CI, 1–1.07; P = 0.035), and LOD score on day 1 (OR, 1.28/point; 95% CI, 1.08–1.54; P = 0.003).

Conclusion

PSE strongly and independently predicts a poor outcome in comatose CA survivors receiving therapeutic hypothermia, but some patients with PSE survive with good functional outcomes. PSE alone is not sufficient to predict failure to awaken after CA in the era of therapeutic hypothermia.

Introduction

Recent guidelines issued by the American Academy of Neurology identify five factors invariably associated with a poor outcome of cardiac arrest survivors, namely, myoclonus on day 1; bilateral absence of the N20 component on somatosensory evoked potentials following median-nerve stimulation on days 1–3; serum neuron-specific enolase levels >33 μg/L on days 1–3; absence of pupillary or corneal reflexes; and extensor or absent motor response to pain stimuli on day 3 [1].

However these guidelines may have been changed by the introduction of therapeutic hypothermia and would need a reappraisal 2, 3, 4, 5, 6, 7, 8, 9. The American Heart Association and the European Resuscitation Council have taken into account this parameter in their Guidelines of Resuscitation 2010. It is now recommended to apply a minimum of 72 h of observation after restoration of spontaneous circulation and to systematically associate two prognostic parameters at least before predicting poor outcome in comatose survivors after cardiac arrest treated with therapeutic hypothermia 10, 11.

Early myoclonus, unlike later myoclonus of Lance–Adams syndrome [12], is of prognosis concern and appears in comatose survivors during the first days after cardiac arrest. Myoclonus can originate in cortical, reticular and/or spinal structures. Subcortical myoclonus is not associated with epileptiform activity but EEG recording can demonstrate bursts synchronous with the jerks. Cortical myoclonus consists of brief and multifocal touch-sensitive jerks of distal peripheral muscles on both sides of the body and is characterized by epileptiform activity on EEG recording 13, 14. Postanoxic status epilepticus (PSE) is an electrographic entity characterized by epileptiform activity on EEG recording that is inconstantly associated with early myoclonus 2, 15.

Interestingly, early myoclonus prognostic significance was reassessed by Fugate [16] and Rossetti [17] that demonstrated contrasting results since the therapeutic hypothermia era. Favorable outcomes have been reported in patients with PSE [2]. Moreover, in a retrospective study, PSE was independently associated with hospital mortality, emphasizing the need for effectively treating this complication [15]. The prognostic significance of PSE has not been evaluated prospectively as an independent factor of outcome since the introduction of therapeutic hypothermia. We conducted a prospective observational cohort study of adult survivors of cardiac arrest to determine 1-year mortality and functional outcomes and to assess the prognosis significance of PSE.

Section snippets

Materials and methods

The ethics committee of the French Society for Critical Care approved this prospective observational study.

Results

The patient flow chart is shown in Fig. 1. Of the 174 patients admitted to the ICU for postanoxic coma during the 5-year study period, 68 did not meet the inclusion criteria, leaving 106 patients for the study.

Discussion

In this prospective study of 106 patients with coma after cardiac arrest, 72 (67.9%) patients died within 1 year after cardiac arrest and only 31 (29.3%) had a good recovery defined as a CPC score of 1 or 2. PSE developed in 33 (31%) patients early after the restoration of spontaneous circulation, of whom only 2 (6%) were alive with a good recovery after 1 year. By multivariable analysis, PSE was the strongest factor independently associated with a poor outcome (CPC > 2).

Previous studies of

Contributors

SL conceived, designed, and supervised the trial. SL, JH, SM, JP and GT collected the data; and SL coordinated the data collection. SL, JH, and MRR analyzed and interpreted the data. MRR was in charge of the statistical analysis. SL, JH, and SM wrote the first draft of the paper. All authors approved the final version of the manuscript.

Conflicts of interest statement

We have no conflicts of interest.

Collaborators

The following collaborators participated in the study: Juliette Audibert, Intensive care unit (site investigator), CH André Mignot, Le Chesnay (78); Aihem Yehia, Intensive care unit (site investigator), CH André Mignot, Le Chesnay (78); Hager Ben Mokhtar, Intensive care unit (site investigator), CH André Mignot, Le Chesnay (78); Nathalie Abbosh, Intensive care unit (site investigator), CH André Mignot, Le Chesnay (78); Pierrick Cronier, Intensive care unit (site investigator), CH André Mignot,

Acknowledgment

We thank A. Wolfe, MD, for helping to prepare the manuscript.

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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.2012.11.001.

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