DOSE-RESPONSE RELATIONSHIP BETWEEN AORTIC INFUSIONS OF POLYMERIZED BOVINE HEMOGLOBIN AND RETURN OF CIRCULATION IN A CANINE MODEL OF VENTRICULAR-FIBRILLATION AND ADVANCED CARDIAC LIFE-SUPPORT

Objectives: Return of spontaneous circulation after cardiac arrest may be a function of vital organ perfusion, Selective aortic perfusion an d oxygenation with oxygenated ultrapurified polymerized bovine hemoglo bin improves vital organ perfusion and is an effective adjunct in the treatment of cardiac arrest, This study determined the dose-response r elationship between intra-aortic oxygenated ultrapurified polymerized bovine hemoglobin and return of spontaneous circulation, Design: Rando mized, interventional study, using a clinically relevant model of vent ricular fibrillation with a prolonged arrest time and cardiopulmonary resuscitation based on external chest compression and aortic occlusion with oxygenated ultrapurified polymerized bovine hemoglobin infusion, Setting: University resuscitation research laboratory, Subjects: Fast ed, mongrel dogs (>20 kg), Interventions: After alpha-chloralose anest hesia, blood gases and vital signs were normalized, Electrocardiogram, aortic arch, and intraesophageal pressures were measured continuously , A descending aortic occlusion-infusion balloon catheter was placed t hrough the femoral artery, Ventricular fibrillation was induced and ba sic life support was begun after 10 mins, Interanimal differences in b asic life support were minimized by standardization of the esophageal pulse pressure and aortic blood gases, At 13 mins, the aortic occlusio n balloon was inflated and a dose of 10, 20, or 30 mL/kg of ultrapurif ied polymerized bovine hemoglobin was infused at 300 mL/min. Defibrill ation was attempted at the end of the infusion, Measurements and Main Results: Only two of five animals given 10 mL/kg of ultrapurified poly merized bovine hemoglobin had return of spontaneous circulation, vs, f our of five animals given 20 mL/kg, and all seven animals given 30 mL/ kg, All resuscitated animals were alive at 1 hr after return of sponta neous circulation, Conclusions: There is a dose-response relationship between the volume of oxygenated ultrapurified polymerized bovine hemo globin administered by selective aortic perfusion and oxygenation and return of spontaneous circulation after prolonged cardiac arrest, This result supports the hypothesis that vital organ flow is causally rela ted to improved outcome.