Elsevier

Resuscitation

Volume 84, Issue 11, November 2013, Pages 1546-1551
Resuscitation

Clinical paper
Clinical examination for prognostication in comatose cardiac arrest patients

https://doi.org/10.1016/j.resuscitation.2013.07.028Get rights and content

Abstract

Objective

To build new algorithms for prognostication of comatose cardiac arrest patients using clinical examination, and investigate whether therapeutic hypothermia influences the value of the clinical examination.

Methods

From 2000 to 2007, 500 consecutive patients in non-traumatic coma were prospectively enrolled, 200 of whom were post-cardiac arrest. Outcome was determined by modified Rankin Scale (mRS) score at 6 months, with mRS  3 indicating good outcome. The clinical examination was performed on days 0, 1, 3 and 7 post-arrest, and clinical variables analyzed for importance in prognostication of outcome. A classification and regression tree analysis (CART) was used to develop a predictive algorithm.

Results

Good outcome was achieved in 9.9% of patients. In CART analysis, motor response was often chosen as a root node, and spontaneous eye movements, pupillary reflexes, eye opening and corneal reflexes were often chosen as splitting nodes. Over 8% of patients with absent or extensor motor response on day 3 achieved a good outcome, as did 2 patients with myoclonic status epilepticus. The odds of achieving a good outcome were lower in patients who suffered asystole (OR 0.187, 95% CI: 0.039–0.875, p = 0.033) compared with ventricular fibrillation or non-perfusing ventricular tachycardia, but some still achieved good outcome. The absence of pupillary and corneal reflexes on day 3 remained highly reliable for predicting poor outcome, regardless of therapeutic hypothermia utilization.

Conclusion

The clinical examination remains central to prognostication in comatose cardiac arrest patients in the modern area. Future studies should incorporate the clinical examination along with modern technology for accurate prognostication.

Introduction

Neurological prognostication in comatose cardiac arrest survivors remains challenging. Despite advances in ancillary testing, the clinical examination continues to lend valuable insights to outcome. Levy et al. published their landmark study in 1985, using the rigorous definition of coma as complete absence of purposeful responses to the self or environment.1 Subsequently there have been significant advances in treatment options, including therapeutic hypothermia (TH). Many prognosis studies included patients who were not truly comatose,2 who commonly achieve good outcomes, thus weakening predictive accuracy.

Clinical signs that historically predict poor outcome include absent pupillary and corneal reflexes, and motor response of none or extension 3 days post-arrest.3, 4 We previously published our findings from 500 patients with non-traumatic coma from all causes.5 Herein we have modernized Levy et al.’s approach, focusing on the cardiac arrest population but staying true to the formal definition of “coma” so that the correct population is studied: patients in whom the prognosis is truly uncertain. Our hypothesis was that the clinical examination remains valuable for predicting outcome in comatose cardiac arrest patients, even with modern therapies and management that influence outcome. Prognostication in comatose post-cardiac arrest patients has evolved with advances in critical care and ancillary studies, and modern statistical methods based on the neurological examination provide important prognostic information.

Section snippets

Methods

We used the methodology employed in a previous study.5 In brief, from October 2000 to September 2007, 500 consecutive non-traumatic coma patients were enrolled in an IRB-approved, HIPAA-compliant, observational single academic center cohort study; 200 were comatose secondary to cardiac arrest. Waiver of consent was granted to enroll patients given the observational nature; consent was required only for survivors to subsequently assess outcome at 6 months. Patients were recruited from the

Results

A total of 34 patients (17%) did not have an examination on day 0. Table 1 presents the baseline characteristics by good/poor outcome. Good outcome (mRS  3) was achieved in 9.9% of patients; 5% achieved an excellent outcome (mRS 0 or 1). Of those who died in hospital, 152 (85%) died secondary to withdrawal of life-sustaining therapies, 20 (11%) progressed to brain death and 6 (3%) experienced a fatal second cardiac arrest. The initial cardiac rhythm correlated with outcome (Table 2). Asystolic

Discussion

The American Academy of Neurology's Practice Parameters (AANPP) for determining prognosis in comatose cardiac arrest survivors emphasize absent pupillary or corneal reflexes, or motor response of none or extensor posturing to noxious stimulation.4 The basis of these recommendations stems from data spanning several decades, with limited detail regarding examinations and including patients not strictly comatose. The clinical examination remains highly useful: it is reproducible, noninvasive, not

Conclusion

The neurological examination remains central to prognosis determination in comatose cardiac arrest patients, including those who undergo therapeutic hypothermia. Absent pupillary and corneal reflexes remain accurate predictors of poor outcome. Physicians are encouraged to use all of the tools at their disposal, including the neurological examination, electrophysiology and neuroimaging, to accurately prognosticate for a given patient.

Conflict of interest statement

There are no real or apparent conflicts of interest, including financial interests, activities, relationships or affiliations.

Acknowledgements

Dr. Yang is supported by Award Number P50DA010075-16 from the National Institute on Drug Abuse and NIH/NCI R01 CA168676. The content of this research is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute on Drug Abuse or the National Institute of Health. There were no other sources of funding or support for this research.

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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.2013.07.028.

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