959-102 What “Dose” of Oxygen is Required in Treating Prolonged Cardiac Arrest

IntroductionSelective aortic (Ao) perfusion and oxygenation (SAPO) with oxygenated ultra-purified polymerized bovine hemoglobin (UPBH) is an effective adjunct to ACLS in the treatment of cardiac arrest. The optimal volume of oxygenated UPBH, equivalent to a dosage of oxygen, is not known.PurposeDetermine the dose/response relationship between intra-Ao UPBH and return of spontaneous circulation (ROSC).MethodsRandomized, interventional study using a canine model of VF with a prolonged “down-time” and CPR based on external chest compression. After chloralose anesthesia, the blood gases and vital signs were normalized. ECG, Ao arch and intra-esophageal pressures were measured continuously. A descending Ao occlusion-infusion balloon catheter was placed through the femoral artery. Ventricular fibrillation was induced and BLS begun after 10min, Inter-animal differences in BLS were minimized by standardization of esophageal pulse pressure and Ao blood gases. At 13min. the Ao occlusion balloon was inflated and 10, 20 or 30cc/kg of UPBH (equivalent to 1.8,3.6, and 5.4ml 02/kg) was infused at 300cc/min. Defibrillation with 8 J/kg was attempted at end infusion.ResultsN=17. Only 2 of 5 animals given 10cc/kg of UPBH had ROSC, verses 4 of 5 given 20cc/kg, and all 7 animals given 30cc/kg had ROSC (p=0.05). All resuscitated animals were alive at one hour.ConclusionsThere is a dose-response relationship between the volume of oxygen administered by SAPO and the rate of ROSC after prolonged cardiac arrest. Thirty cc/kg of UPBH, equivalent to 5.4ml 02/kg, appeared optimal in this model