Abstract 307: Selective Brain Perfusion in Addition to Emergency Cardiopulmonary Bypass Resuscitation After Prolonged Asphyxial Cardiac Arrest: Feasibility Studies in a Novel Rodent Model

Abstract

Brief Objectives: Poor neurological recovery is the major limiting factor in the use of emergency cardiopulmonary bypass (ECPB) in cases of refractory cardiac arrest. To better control cerebral perfusion we developed a novel rodent model of selective brain perfusion (SBP) in addition to ECPB resuscitation. We conducted pilot studies on feasibility of this unique approach Methods Male: Sprague-Dawley rats (450-550 gm) were instrumented for ECPB with venous and arterial cannulation. To provide SBP, we additionally cannulated the right common carotid artery (RCCA) and confirmed SBP flow with a Transonic flow probe. First feasibility studies were performed to demonstrate bilateral cerebral flow from unilateral perfusion, and to ascertain tolerability of surgical procedure. To test gross survival effects of SBP in the setting of lethal cardiac arrest, three groups of rats underwent 15 min of asphyxial cardiac arrest followed by resuscitation with 30-min ECPB using 3 different strategies: normothermia with SBP (NT w/ SBP, N=3), hypothermia with SBP (HT w/ SBP, N=3), and hypothermia without SBP (HT w/o SBP, N=3). After: ECPB, rats were weaned off ECPB, wounds were closed, and 4-h mechanical ventilation and IV fluids were provided. Rats were then extubated and checked for neurological score (NS: 0-12), development of gross seizures, and the length of time of survival after extubation until death. Results: To access feasibility, we injected blue dye into the RCCA and we confirmed that single RCCA perfusion could perfuse the whole brain. Sham studies with rats (3) were conducted with full SBP and ECPR instrumentation for 30-min, then the RCCA was ligated, which confirmed that all rats survived without neurological deficits or limb injury for 3 days. In the pilot survival studies, the longest survival after extubation was observed in HT w/ SBP animal (7.0h±3.0), in contrast to both HT w/o SBP (1.1h±0.4) and HT w/o SBP (2.3h±0.9 ). Similar trends for improved neuro score and fewer seizure were observed for the HT w/ SBP animals. Conclusion: Our pilot study showed the feasibility of using brain selective perfusion in a rodent model of highly lethal cardiac arrest. SBP plus hypothermic ECPB trended toward improved survival and neurological outcome and warrants further study.