Although Norwood's first stage palliative procedure has been adopted by most proponents of reconstructive surgery for hypoplastic left heart syndrome, several technical modifications have recently been introduced. Some are intended primarily to minimize the adverse effects of cardiopulmonary bypass, hypothermic circulatory arrest, or both. Some are intended to simplify the technical performance of the initial palliative procedure. As the number of patients surviving staged reconstructive surgery for hypoplastic left heart syndrome grows steadily, there is a shift in emphasis toward investigation of methods to minimize morbidity. Specifically, the quality of life after staged reconstructive surgery may be affected by the potential for neurologic injury associated with bypass, deep hypothermia, and circulatory arrest. The pathology of cerebral injury includes ischemic cerebral necrosis, periventricular leukomalacia, necrosis of the brain stem, and intracranial hemorrhage. Neurologic injury associated with cardiac surgery during infancy is undoubtedly multi-factorial, and as yet is poorly and incompletely understood. Several surgical teams, nonetheless, have revised the technical aspects of the palliative operations with a goal of minimizing the duration of hypothermic circulatory arrest.
Glutamate excitotoxicity: A mechanism of neurologic injury associated with hypothermic circulatory arrest