The evolution of serum astroglial S-100 beta protein in patients with cardiac arrest treated with mild hypothermia.

Objective: To study the effects of mild hypothermia on the 24h concentration of serum astroglial of S-100 beta protein in patients who survived cardiac arrest (CA).
Design: A prospective, randomised, clinical study in a university teaching hospital.
Patients: Sixty-one resuscitated patients were randomised into two prospective studies, known as the short study period (SSP) (n = 33 patients) and the long study period (LSP) (n = 28 patients). In the SSP study, patients older than 18 years of age and surviving asystole or pulseless electrical activity were included. In the LSP study, patients with ventricular fibrillation (VF) or non-perfusing ventricular tachycardia (VT) aged between 18 and 75 years were included. In each of the study groups, the patients were further randomised into either normothermic or hypothermic subgroups. The standard supportive therapy was similar, only the devices used to reduce the body temperature and the period of hypothermia were different. Serum samples for the measurement of astroglial S-100 beta protein were collected at admission and 24h later.
Results: During the first 24h after the cardiac arrest, the concentration of astroglial serum S-100 beta protein decreased significantly in the hypothermic cohort. In the normothermic cohort, the decrease of serum astroglial S-100 beta protein was less pronounced and even increased in the normothermic LSP group.
Conclusion: Induced mild hypothermia reduced the 24h astroglial serum S-100 beta protein concentration and might play a neuroprotective effect after cardiac arrest.