CARDIAC-SURGERY IN THE YOUNG INFANT - AN IN-VIVO MODEL FOR THE STUDY OF HYPOXIC-ISCHEMIC BRAIN INJURY

The remarkable advances in survival of infants with congenital heart d isease who undergo cardiac surgery are due in large part to techniques that require periods of markedly decreased or arrested circulation. A n obvious prerequisite has been the development of techniques that pro tect critical organ systems, particularly the nervous system, during t he often prolonged periods of attenuated oxygen delivery. Despite the manifest success of current neuroprotective strategies, a substantial postoperative neurologic morbidity persists in these infants. The plan ned periods of hypoperfusion provide a unique clinical opportunity for the prospective, in vivo study of cerebral responses to hypoxic-ische mic stress. Furthermore, the potential for pretreatment intervention i s likely to make this an active setting for the clinical trial of futu re neuroprotective strategies. This article will evaluate the strength s and limitations of this clinical model, with particular reference to the mechanisms of hypoxia-ischemia and potential interventions.