Cerebral protection during CPB

Despite advances in surgical, anesthetic, and neuroprotective strategies, cerebral injury after cardiac surgery remains a significant source of post-operative morbidity and is responsible for an increasing proportion of peri-operative deaths. Technological advancements have allowed cardiac surgery to be performed on a progressively older and sicker population who, in turn, are at increased risk for the associated cerebral injury. The underlying mechanism of the associated cerebral injury is incompletely understood. While considered multifactorial, the most importantly cited etiologic factors are cerebral macroand microembolism and hypoperfusion, exacerbated by ischemia/reperfusion injury. Extensive research has been undertaken in an attempt to minimize the incidence of peri-operative cerebral injury, and both pharmacological and non-pharmacological strategies have been investigated. Although many agents showed promise in pre-clinical studies, there is currently insufficient evidence from clinical trials to recommend the routine administration of any pharmacological agents for neuroprotection during cardiac surgery. Non-pharmacological strategies that can be recommended on the basis of evidence include TEE and epiaortic ultrasound guided assessment of the atheromatous ascending aorta with appropriate modification of cannulation, clamping or anastomotic technique and optimal temperature management. Largescale randomized controlled trials are still required to further address the issues of optimal pH management, glycemic control, blood pressure management, and hematocrit during CPB.