Abstract 243: Pulsatile Versus Nonpulsatile Emergency Cardiopulmonary Bypass: Impact on Early Regional Brain Perfusion After Lethal Cardiac Arrest in Rats
Background: An increasing amount of clinical data suggests that emergency cardiopulmonary bypass (ECPB) is an effective tool for resuscitation from prolonged cardiac arrest. Next to controlling pharmacological components of the reperfusate, ECPB also allows definition of physical characteristics of reperfusion. Pulsatile reperfusion is a intriguing strategy but has not been studied in the setting of ECPB despite its technical feasibility. Thus we aimed at testing the influence of a pulsatile reperfusion component to early brain perfusion after lethal cardiac arrest in a rodent ECPB model.
Methods: After anesthesia and instrumentation, male Sprague-Dawley rats (448±41g) underwent 20 min of untreated asphyxial arrest and were resuscitated with normothermic ECPB with either pulsatile (150 beats/min; 50 mL/min; n=8) or non-pulsatile flow (50 mL/min; n=8). No vasopressors were administered. ROSC was prevented by occluding the right ventricle. At 3 min, FITC-dextran 70 was injected into the bypass circuit. Two minutes later ECPB was stopped, the brain removed and brain slices at defined levels (Bregma -0.3 mm, -1.4 mm, -3.3 mm, -11.3 mm) mounted for fluorescent microscopy and blinded quantification of the area of FITC-stained perfused cerebral microvessels. Perfused areas were quantified for the whole brain, cortex, caudate putamen and hippocampus.
Results: The overall perfused cortical area (41±13%) was significantly higher than the non-cortical area (20±11%), with a trend towards better perfusion with pulsatile bypass in the deeper brain regions (p=0.07). While no differences in mean arterial blood pressure (MAP) between groups were present, perfused areas in putamen (p=0.04) and hippocampus (p=0.03) were significantly higher in animals treated with pulsatile ECPB.
Conclusions: The data suggests that pulsatile ECPB may be of benefit to improve perfusion of deeper brain regions after prolonged cardiac arrest and especially of those areas known to be vulnerable to cerebral hypoxia/ischemia. Additional studies are warranted to further define the role of pulsatile ECPB for resuscitation from lethal cardiac arrest.
- © 2012 by American Heart Association, Inc.