ABSTRACT
OBJECTIVE: This study was designed to develop a piglet model of neonatal hypoxic-ischemic encephalopathy, which would allow for serial assessments of long-term neurodevelopmental impairment. METHODS: In 12 newborn piglets, we produced hypoxia by 8% oxygen breathing for 5-91 minutes. We combined ischemia by reversible bilateral common carotid artery occlusion for varying times. Outcome measures were clinical neurological evaluation, magnetic resonance spectroscopy studies and brain histology. RESULTS: Those animals which received intravenous sedation and no mechanical ventilation showed poor tolerance to hypoxia-ischemia and died early in the course of the experiments. The use of inhalation anesthesia during surgical procedures and mechanical ventilation during hypoxia-ischemia was associated with long-term survival. Seven of eight animals that survived > or = 48 hr showed clinical neurological abnormalities, that later resolved. Magnetic resonance spectroscopy measurements did not change significantly following hypoxia-ischemia. None of the animals had histopathological brain lesions. CONCLUSION: When subjected to acute hypoxia-ischemia, piglets were likely to survive only if they were given such supportive measures as anesthesia and mechanical ventilation. Even with hypoxic-ischemic injury sufficient to produce acute signs of neurological dysfunctions, longterm, stable survival with no evident brain histopathological abnormalities was possible.
