Figure 2: Study Protocol

Neonatal swine were acclimated with bottle feedings 5 time per day (blue marks) for 5 days prior to experimentation. On the day of experimentation, swine were anesthetized and instrumented for cardiopulmonary bypass. Ischemic injury included circulatory arrest for 75 min at 25°C. Swine were then rewarmed and decannulated and underwent mechanical ventilation using a standardized intensive care protocol. Swine were ventilated for a total of 24 h (including pre- and post-operative treatments) with or without 2.4% inhaled hydrogen therapy (n = 8 swine per group). Videotaped neurologic examinations (green marks) took place prior to and daily following the circulatory arrest period. Swine underwent sedated brain MRI followed by terminal cerebral perfusion for histopathologic examination on postoperative day 3. F = Friday; M = Monday; MRI = magnetic resonance imaging; R = Thursday; RN = nursing care; S = Saturday/Sunday; W = Wednesday.