Aortic Hemostasis and Resuscitation: Preliminary Experiments Using Selective Aortic Arch Perfusion With Oxygenated Blood and Intra-aortic Calcium Coadministration in a Model of Hemorrhage-induced Traumatic Cardiac Arrest.

Abstract

Selective aortic arch perfusion (SAAP) uses a thoracic aortic balloon occlusion catheter for heart and brain perfusion in cardiac arrest to achieve return of spontaneous circulation (ROSC). SAAP with oxygenated stored blood was studied in a model of hemorrhage-induced cardiac arrest. The study hypothesis was that intra-aortic calcium coadministration would be required to maintain normal aortic arch blood ionized calcium during SAAP and to achieve ROSC. Twelve anesthetized, domestic swine underwent severe hemorrhage and liver injury resulting in cardiac arrest. Whole blood and packed red blood cells (RBCs) stored in citrate anticoagulant served as perfusates for SAAP. Experiments were performed with four combinations of SAAP with oxygenated stored blood and intra-aortic calcium gluconate infusion: 1) whole blood without calcium, 2) whole blood with calcium, 3) lactated Ringers-diluted packed RBCs with calcium, and 4) normal saline-diluted packed RBCs with calcium. Aortic arch blood ionized calcium was monitored. Occurrence of ventricular dysrhythmias, success rate for ROSC, and the need for simultaneous intra-aortic calcium infusion were assessed. Selective aortic arch perfusion using whole blood without intra-aortic calcium (n = 2) resulted in severe aortic blood ionized hypocalcemia, refractory ventricular fibrillation, and no ROSC. SAAP using whole blood with intra-aortic calcium (n = 4) resulted in ROSC in all four animals. Two of four developed ventricular fibrillation that was successfully defibrillated. SAAP using packed RBCs with intra-aortic calcium resulted in ROSC in all six animals, but the intra-aortic calcium dose needed to maintain normal aortic arch blood ionized calcium levels was one-third of that needed for SAAP with whole blood. Dilution of packed RBCs with lactated Ringers (n = 2) resulted in formation of small clots in the perfusion circuit which were not seen with packed RBCs diluted with normal saline (n = 4). Selective aortic arch perfusion with stored whole blood or packed RBCs requires simultaneous intra-aortic calcium infusion to overcome citrate anticoagulant calcium binding, avoid refractory ventricular fibrillation, and allow for ROSC.