Below are some take home points from a recent review:
Cooling remains accepted as an established modality to improve neurologic outcome but the optimal temperature target is uncertain.
The incorporation of hypothermia into post arrest care has completely changed neuro assessment post cardiac arrest.
In the hypothermia era the assessment is almost always delayed. The optimal timing remains under investigation but is now believed to be 4-5 days post arrest.
When hypothermia is applied it is rarely possible to declare poor neurologic prognosis in the immediate post arrest period.
Doing so would require exam findings of total loss of brain stem function. The authors recommend that such a clinical assessment be supplemented by testing such as EEG.
The motor response at 48-72 hours after sedative withdrawal may be helpful.
A motor response that localizes a painful stimulus is a favorable sign and obviates the need for further evaluation.
Pupillary and corneal responses may be helpful at 72 hours post arrest.
Bilateral absence at that time point is strongly associated with a poor outcome.
Post arrest seizures and myoclonus can be difficult to interpret.
They are often confused with one another. Neither is considered reliable for neurologic prognostication after cardiac arrest. Status myoclonus, a severe and generalized form of post anoxic myoclonus, is a poor prognostic sign and in years past was considered a reliable indicator. That thinking has recently changed after a few reports of occasional favorable outcome.
The use of EEG and imaging modalities was discussed in the review.