Abstract 20198: Inhaled Hydrogen Gas During DHCA Diminishes Neurologic Injury in Swine
Introduction: Evidence of ischemia-reperfusion injury (IRI) is common in neonates following surgery for congenital heart disease. Inhaled hydrogen gas may mitigate this injury by selectively reducing the hydroxyl radical, a primary mediator of IRI. We examined whether the administration of hydrogen (H2) gas diminishes evidence of neuronal injury following experimental hypothermic circulatory arrest.
Methods: Neonatal, female Yorkshire swine (3.2-4.1 kg) were anesthetized, intubated, instrumented, and cannulated for cardiopulmonary bypass via median sternotomy. Swine were (1) cooled to 25°C (rectal) over 30 minutes, (2) then underwent 75 minutes of circulatory arrest, (3) then rewarmed to 37°C over 60 minutes, (4) then weaned from cardiopulmonary bypass, (5) then ventilated in an ICU environment for 24 hours, (6) then extubated and observed for 5 days, (7) then underwent brain MRI and neurohistologic exam. Swine were randomized to receive treatment with (n=4) or without (n=5) 2.4% hydrogen gas during phases 1-5. Certified, premixed 2.4% H2 with oxygen, air, and carbogen were used.
Results: H2 administration was safe in the setting of cardiac surgery. There was no difference in rectal temperature between groups (P=0.6). The primary endpoint was neurologic function as quantified by the Swine Neurologic Deficit Score (videotaped, reviewers blinded to treatment allocation). H2-treated swine exhibited significantly better (i.e. lower) scores over time (P<0.001, repeated measures ANOVA, A). A trend towards fewer swine exhibited seizure activity in the H2 group (0/4 vs 3/5, P=NS). H2-treated swine exhibited subjectively less white matter injury (brain MRI, T1) than present on control animals (B). H2-treated swine exhibited less neurohistopathologic evidence for axonal injury than did controls (P=0.03, C).
Conclusions: Administration of 2.4% H2 is safe during cardiac surgery and diminishes neurologic injury following circulatory arrest.
Author Disclosures: A. Cole: None. A. Raza: None. A. Nedder: None. P.E. Grant: None. H.G. Lidov: None. J.E. Mayer: None. J.N. Kheir: None.
This research has received full or partial funding support from the American Heart Association, Yes.
- © 2017 by American Heart Association, Inc.