Intermittent retrograde cerebral perfusion during prolonged period of hypothermic circulatory arrest - A study in a chronic porcine model

Previous studies have shown that although retrograde cerebral perfusion (RC P) improves cerebral outcome during hypothermic circulatory arrest (HCA), R CP exposes the brain to subsequent edema. In this study, we have compared i ntermittent RCP (I RCP) with continuous RCP (C-RCP) and HCA alone to determ ine whether the rare of fluid sequestration can be decreased without losing the beneficial effects of RCP. Eighteen pigs were randomly assigned to und ergo 75 min of I-RCP, C-RCP or I-ICA at 20 degrees C. Hemodynamic and metab olic measurements were carried out for upto 20 h. Behavioral assessments we re examined until day 7, when histopathologic analysis of the brain was per formed. The median amount of fluid sequestered was 145 mi after C-RCP and - 50 mi after I-RCP (p = 0.04). The mean brain weight of the animals that die d within the first postoperative day was significantly higher than that in electively sacrificed animals in the C-RCP group (p = 0.04). These data sug gest that if RCP is implemented intermittently, the rate Of cerebral edema can be decreased, without compromising the benefits of this strategy.