Cerebral Protection During Cardiopulmonary Bypass

A summary of methods of cerebral protection during cardiopulmonary bypass and trends in technological development.

This paper reports on the current relevant literature on cardiopulmonary bypasses, which provide a temporary substitute for a patient’s heart and lungs during the course of open-heart surgery. In particular, it looks at how the memory loss and other cognitive problems long known to result from bypass surgery are often minimized by heart surgeons as being merely transient problems and how there is a need for cerebral protection, since studies have shown that for a substantial minority who undergo this operation, will incur mental impairment years later. A review of the literature is followed by a summary of the research in the conclusion.

Need for Cerebral Protection
Cerebral Protection Methods
Technological Developments
Today, the trend is towards providing brain protection with either antegrade or retrograde perfusion during circulatory arrest. The study by Igari et al. and work by others have demonstrated the ability to isolate cerebral perfusion from lower-body perfusion while performing the necessary great vessel anastomoses. A Boston Children’s Study that cited by these researchers demonstrated the overall superiority of low-flow versus no-flow that may have applicability to the adult situation as well. In this study, the authors used a moderately hypothermic perfusate, thus decreasing cerebral oxygen consumption. The combination of hypothermia to decrease metabolic rate and moderate-flow perfusion to wash out metabolites provides cerebral protection (Igari et al., 1999, p. 108).