Abstract 257: Unselective Pulmonary Vasodilation is an Important Factor in Sodium Nitroprusside Enhanced Cardiopulmonary Resuscitation Improved Blood Flow

Abstract

Introduction: Sodium nitroprusside enhanced CPR (SNPeCPR) is a novel CPR method that includes a potent vasodilator, active compression-decompression CPR, an inspiratory impedance threshold device and abdominal binding. SNPeCPR has been shown to improve vital organ flow and functional survival outcomes compared to standard CPR methods in animals. We hypothesize that one of the main effects of SNPeCPR mediated increase in cardiac output during prolonged resuscitation is profound pulmonary artery vasodilation. Methods: After electrically induced VF was left untreated for 3 min, 20 (44-48Kg) pigs were randomized to receive SNPeCPR (10) or standard CPR (10) for a total of 30 min; the first 10 minutes were BLS CPR followed by twenty minutes of ACLS. During ACLS, animals were given IV SNP (1mg bolus) or standard epinephrine (0.5mg) q5 min until ROSC or 45 min total CPR. Shocks were delivered after 30 minutes of CPR at 300J. If ROSC was achieved, animal was monitored until 4-hour endpoint. Ventilations were provided with 10ml/kg at 10/min with a mechanical ventilator. Initially during CPR, room air was used and FiO2 was adjusted q5 minutes to maintain O 2 %saturation &gt 92% based on ABG. Lactic acid was also measured. Aortic, right atrial, and coronary artery pressures and carotid blood flow were recorded continuously. A-a oxygen gradient was measured with standard technique. Results: SNPeCPR animals documented a significantly higher mean CPP, lower lactic acid and 3x higher carotid blood flow over 30 minutes compared to standard CPR as previously documented. A-a oxygen gradient was dramatically increased in the SNPeCPR and coincided with a decreased lactate level (see Figure 1). Discussion: SNPeCPR causes profound pulmonary vasodilation and increases flow through non-ventilated lung areas. Despite that, the overall increase in forward flow leads to higher minute O 2 delivery and improved tissue perfusion. SNPeCPR should be used with 100% oxygen in the first human clinical trial.