Cerebral Blood Flow Regulation during Cardiopulmonary Bypass: Correlation with Postoperative Neurologic and Neuropsychologic Deficits

Abstract

Postoperative neuropsychologic deficits after cardiopulmonary bypass for coronary revascularization or open cardiac procedures remains a disturbing and poorly understood complication. The etiology of postoperative neuropsychologic deficits is being aggressively investigated, but remains controversial. It has been widely speculated that these complications are the results of either: 1) embolism of air or particulate matter, or 2) hypoperfusion during cardiopulmonary bypass. Since the incidence of postoperative neuropsychologic deficits (PNPD) is significantly higher after cardiac than non-cardiac surgery, events associated with cardiopulmonary bypass (CPB) must lead to these complications. The fact that many of the PNPD are transient and nonfocal lends credence to the possibility of hypoperfusion or changes in cerebral autoregulation and cerebral blood flow (CBF) as a mechanism for these injuries. Therefore, the research on neurologic and neuropsychologic outcome at The Duke Heart Center has centered around CBF and changes occurring during cardiopulmonary bypass.