Abstract Sa602: Novel gas mixture combined with an auto-transfusion tourniquet enhances cerebral O ₂ transport and hemodynamic indices in CPR swine

Background: The cognitive outcome of CPR is poor. This study aims to evaluate if enhancing blood flow to the brain and oxygen dissociation from the hemoglobin, improve cerebral O 2 delivery during CPR in cardiac arrest swine. Methods: Standard swine-CPR model of induced VF and recovery was treated with an auto-transfusion tourniquet (A-TT®; HemaShock® (HS) Oneg HaKarmel Ltd. Israel) and ventilation with a novel mixture of Oxygen – 30%, CO 2 – 5%, and Argon 65% (COXAR™). Five swine received the study treatment and 5 controls standard therapy. All animals were anesthetized, ventilated, and instrumented for blood draws and pressure measurements. Five minutes of no-CPR arrest were followed by 10 minutes of mechanical CPR with and without COXAR-HS enhancement followed by defibrillation and 45 minutes post ROSC follow-up of. Results: All 5 COXAR-HS™ animals were resuscitated successfully as opposed to 3 of the control animals (p=0.09 NS). Hemodynamic indices: Systolic (p<0.05), and diastolic (p<0.01) blood pressures, coronary (p<0.001) and cerebral (p<0.05) perfusion pressure were higher in the COXAR-HS group after ROSC, as well as cerebral flow and O 2 delivery (p<0.05). Blood pressure maintenance after ROSC required dose of norepinephrine in the 3 control animals that had ROSC vs the 5 COXAR-HS animals (p<0.05). PO 2 and SO 2 in the jugular vein exceeded 50 mmHg and 50%, respectively with COXAR-HS. Discussion: The COXAR-HS group hemodynamic and gas exchange were significantly superior post ROSC compared to the control. The higher PjvO 2 and SjvO 2 indicate enhanced O 2 delivery to the brain mitochondria, while limb compression by the HS counteracts the vasodilatory effect of the CO 2 . The much lower and less toxic F I O 2 in the COXAR-HS group was sufficient and there were no adverse effects of Argon. Conclusions: The combination of the HemaShock peripheral vasoconstrictive effect with the COXAR vasodilative effect enhance ROSC and brain oxygen delivery.