Inhalation of high concentration hydrogen gas improves short-term outcomes in a rat model of asphyxia induced-cardiac arrest

Cardiogenic global brain hypoxia-ischemia is a devastating medical problem that is associated with unfavorable neurologic outcomes. Low dose hydrogen gas (up to 2.9%) has been shown to be neuroprotective in a variety of brain diseases. In the present study, we investigated the protective effect of water by electrolysis-derived high concentration hydrogen gas (60%) in a rat model of asphyxia induced-cardiac arrest and global brain hypoxia-ischemia. High concentration hydrogen gas was either administered starting 1 hour prior to cardiac arrest for 1 hour and starting 1 hour post-resuscitation for 1 hour (pre- & post-treatment) or starting 1 hour post-resuscitation for 2 hours (post-treatment). In animals subjected to 9 minutes of asphyxia, both therapeutic regimens tended to reduce the incidence of seizures and neurological deficits within 3 days post-resuscitation. In rats subjected to 11 minutes of asphyxia, significantly worse neurological deficits were observed compared to 9 minutes asphyxia, and pre- & post-treatment had a tendency to improve the success rate of resuscitation and to reduce the seizure incidence within 3 days post-resuscitation. Findings of this preclinical study suggest that water electrolysis-derived 60% hydrogen gas may improve short-term outcomes in cardiogenic global brain hypoxia-ischemia.