Hydrogen gas can ameliorate seizure burden during therapeutic hypothermia in asphyxiated newborn piglets

Background: We previously reported that hydrogen (H-2) gas combined with therapeutic hypothermia (TH) improved short-term neurological outcomes in asphyxiated piglets. However, the effect on seizure burden was unclear. Using amplitude-integrated electroencephalography (aEEG), we compared TH + H-2 with TH alone in piglets 24 h after hypoxic-ischemic (HI) insult.Methods: After a 40-min insult and resuscitation, 36 piglets <= 24 h old were divided into three groups: normothermia (NT, n = 14), TH alone (33.5 +/- 0.5 degrees C, 24 h, n = 13), and TH + H-2 (2.1-2.7% H-2 gas, 24 h, n = 9). aEEG was recorded for 24 h post-insult and its background pattern, status epilepticus (SE; recurrent seizures lasting >5 min), and seizure occurrence (Sz; occurring at least once but not fitting the definition of SE) were evaluated. Background findings with a continuous low voltage and burst suppression were considered abnormal.Results: The percentage of piglets with an abnormal aEEG background (aEEG-BG), abnormal aEEG-BG+Sz and SE was lower with TH + H-2 than with TH at 24 h after HI insult. The duration of SE was shorter with TH + H-2 and significantly shorter than with NT.Conclusions: H-2 gas combined with TH ameliorated seizure burden 24 h after HI insult.