Neurologic Injury Following Hypothermic Circulatory Arrest

Cardiothoracic surgeons are faced with the challenge of protecting the brain during the sensitive time of interruption of normal cerebral blood flow. The brain is an exceptionally complex organ with a functional anatomy that is difficult both to understand and assess. Experimental and clinical studies have shown that the mechanism of neural injury is multifactorial. As such, discussions regarding the best surgical strategies for neuroprotection during circulatory arrest are formidable, at best. Although we are armed with excellent experimental and clinical studies that demonstrate the deleterious effects of prolonged exposure to cardiopulmonary bypass (CPB) on brain function and structure, the various neuroprotective strategies, particularly that of deep hypothermic circulatory arrest (DHCA) remain an issue of debate. This is related in part to the gap between the basic science understanding of brain injury caused by these events and the clinical application of various neuroprotective strategies and their subsequent clinical outcomes. The goal here is to address the current understanding of the mechanisms underlying brain injury after HCA and relevant strategies of neural protection, supported by primary experimental data from our laboratory.