Background: We evaluated changes in the levels of urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) in patients undergoing mild hypothermia therapy and compared 8-OHdG expressions in those receiving whole-body cooling or selective head cooling.
Material/Methods: The subjects were 15 patients undergoing mild hypothermia therapy following resuscitation after cardiac arrest in our intensive care unit. We divided the patients into 2 groups receiving either whole-body cooling or selective head cooling, according to their circulatory stability. We examined urinary 8-OHdG level for 1 week and neurological outcomes 28 days after admission.
Results: We observed significant decreases in urinary 8-OHdG levels on days 6 and 7 compared with that on day 1 in the whole-body cooling group. Furthermore, we noted significantly lower urinary 8-OHdG levels after days 5, 6 and 7 in the whole-body cooling group than in the selective head-cooling group. Neurological outcomes were similar in both groups.
Conclusions: Mild hypothermia therapy with whole-body cooling had a greater effect on the suppression of free radical production than selective head cooling. However, selective head cooling might be an appropriate indication for patients with circulatory instability after resuscitation, because it provides neuroprotection similar to that of whole-body cooling.

Keywords: Rewarming, Hypothermia, Induced - methods, Head, Deoxyguanosine - urine, Brain Ischemia - urine, Time Factors