Clinical paperClinical examination for prognostication in comatose cardiac arrest patients☆
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.