Prognosis is poor if patients have any of the following: Myoclonic status epilepticus (bilaterally synchronous twitching of axial structures, often with eye opening and upward deviation of the eyes) that occurs within 24 to 48 hours after cardiac arrest No pupillary light reflexes 24 to 72 hours after cardiac arrest No corneal reflexes 72 hours after cardiac arrest Extensor posturing or no response elicited by painful stimuli 72 hours after cardiac arrest No response 20 milliseconds (N20) after stimulation of somatosensory evoked potential (SEP) Serum neuron-specific enolase level of > 33 mcg / L Preexisting disorders such as coronary artery disease, hypertension, and diabetes mellitus If patients who are unresponsive after cardiac arrest have been treated with hypothermia (often for about 24 hours after arrest), 72 hours should be added to the above times because hypothermia slows recovery of brain metabolism.