Various studies have demonstrated that over 50% of patients presenting for coronary revascularization surgery have evidence of extracranial or intracranial atherosclerotic disease. Although evidence is compelling that cerebral emboli are a major cause of perioperative central nervous system (CNS) morbidity in such patients, it is also apparent that alterations in cerebral perfusion pressure and blood flow can profoundly influence the extent of injury after an embolic insult. In this context, the recent studies demonstrating improved CNS outcomes with applied neuromonitoring in cardiac surgical patients can be understood as reflecting the optimization of CNS perfusion characteristics with potential amelioration of microembolic injury. This review critically evaluates and discusses the relevant characteristics of applied neuromonitoring techniques, including bispectral index (BIS), transcranial Doppler (TCD), and near infrared reflectance spectroscopy (NIRS) in the context of patients undergoing cardiac surgical procedures. Recent outcomes data regarding CNS and related morbidity and the influence of neuromonitoring in these groups are evaluated.
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