Definitions of the strength of the recommendations (A, B, C, U) and classification of the evidence (Class I through Class IV) are provided at the end of the "Major Recommendations" field.
Results and Recommendations
Are the circumstances surrounding cardiopulmonary resuscitation (CPR) predictive of outcome?
Prognosis cannot be based on the circumstances of cardiopulmonary resuscitation (recommendation level B).
Is hyperthermia predictive of outcome?
Prognosis cannot be based on elevated body temperature alone (recommendation level C).
Which features of the neurologic examination of the comatose patient are predictive of outcome?
The prognosis is invariably poor in comatose patients with absent pupillary or corneal reflexes, or absent or extensor motor responses 3 days after cardiac arrest (recommendation level A). Patients with myoclonus status epilepticus within the first day after a primary circulatory arrest have a poor prognosis (recommendation level B).
Which electrophysiologic studies are helpful in determining outcome?
Burst suppression or generalized epileptiform discharges on electroencephalogram (EEG) predicted poor outcomes but with insufficient prognostic accuracy (recommendation level C).
The assessment of poor prognosis can be guided by the bilateral absence of cortical somatosensory evoked potentials (SSEPs) (N20 response) within 1 to 3 days (recommendation level B).
Do biochemical markers accurately predict outcome?
Serum neuron-specific enolase (NSE) levels >33 micrograms/L at days 1 to 3 post-CPR accurately predict poor outcome (recommendation level B). There are inadequate data to support or refute the prognostic value of other serum and cerebrospinal fluid (CSF) biochemical markers in comatose patients after CPR (recommendation level U).
Does monitoring of intracranial pressure and brain oxygenation predict outcome?
There are inadequate data to support or refute the prognostic value of intracranial pressure (ICP) monitoring (recommendation level U).
Are neuroimaging studies indicative of outcome?
There are inadequate data to support or refute whether neuroimaging is indicative of poor outcome (recommendation level U).
Definitions:
Classification of Evidence for Prognostic Article
Class I: Evidence provided by a prospective study of a broad spectrum of persons who may be at risk for developing the outcome (e.g. target disease, work status). The study measures the predictive ability using an independent gold standard for case definition. The predictor is measured in an evaluation that is masked to clinical presentation, and the outcome is measured in an evaluation that is masked to the presence of the predictor. All patients have the predictor and outcome variables measured.
Class II: Evidence provided by a prospective study of a narrow spectrum of persons at risk for having the condition, or by a retrospective study of a broad spectrum of persons with the condition compared to a broad spectrum of controls. The study measures the prognostic accuracy of the risk factor using an acceptable independent gold standard for case definition. The risk factor is measured in an evaluation that is masked to the outcome.
Class III: Evidence provided by a retrospective study where either the persons with the condition or the controls are of a narrow spectrum. The study measures the predictive ability using an acceptable independent gold standard for case definition. The outcome, if not objective, is determined by someone other than the person who measured the predictor.
Class IV: Any design where the predictor is not applied in an independent evaluation OR evidence provided by expert opinion or case series without controls.
Classification of Recommendations
A = Established as effective, ineffective, or harmful for the given condition in the specified population. (Level A rating requires at least two consistent Class I studies.)
B = Probably effective, ineffective, or harmful for the given condition in the specified population (Level B rating requires at least one Class I study or at least two consistent Class II studies.)
C = Possibly effective, ineffective, or harmful for the given condition in the specified population (Level C rating requires at least one Class II study or two consistent Class III studies.)
U = Data inadequate or conflicting; given current knowledge, predictor is unproven.