Management of cardiac arrest is complicated by the lack of a readily available tool identifying individuals who are likely to be successfully resuscitated. S100 beta is a protein that originates in the astroglial cells of the brain, and NSE (Neuron Specific Enolase) is another protein that originates in the neurons themselves. In the laboratory, the concentration of these proteins correlate with evidence of brain damage after head trauma, stroke and exposure to low levels of oxygen. The concentration of these proteins in the blood of human survivors of cardiopulmonary resuscitation in humans is much higher than in patients who were resuscitated but did not survive. However, it is still unclear whether survivors from cardiopulmonary resuscitation have higher levels of these proteins in their blood if they survive with neurological injury secondary to the arrest and resuscitation.

Hypothesis: In humans, the blood concentrations of protein S100 beta and NSE during and after resuscitation can predict who will die despite cardiopulmonary resuscitation and who will survive with neurological injury secondary to the arrest and resuscitation.

Inclusion Criteria:

• All victims of non-traumatic out-of hospital cardiopulmonary arrest (defined as the absence of either spontaneous respiration or palpable pulse or both) within the Jerusalem district.

Exclusion Criteria:

• Patients with do-not-resuscitate orders or an advance directive to that effect.
• Patients with intracranial hemorrhage

All victims of non-traumatic out-of hospital cardiopulmonary arrest (defined as the absence of either spontaneous respiration or palpable pulse or both) within the Jerusalem district.