Postanoxic encephalopathy tests

1. Poor outcome can be reliable predicted with SSEP  (N20) as early as 24 hrs after CPR in over 87%; bilateral absence of the N20 of at least 24 hrs duration is invariably associated with poor outcome. In over 50% of patients the N20 is absent after 24 hrs. 

2. Similarly lack of pupillary and corneal reflexes and of any motor response 3 days after the hypoxic/anoxic insult carry an almost 100% positive predictive value.

3. Serum neuron-specific enolase (NSE) above 33 μg/l proves as accurate as the absence of N20 in the prediction of poor outcome.

4. Isoelectric EEG at 72 hrs or later carries poor prognosis.

5. Burst suppression activity or low voltage activity on EEG.