Abstract 215: Hemodynamics of Absolute, Proportional, and Adaptive Mechanical Chest Compression Strategies in a Swine Model of Pediatric Out-Of-Hospital Cardiac Arrest

Background: Guidelines for pediatric resuscitation recommend a depth of 1.5in or 1/3 anterior-posterior chest diameter for chest compressions (CC) despite little supporting evidence. Objective: To evaluate the hemodynamic effects of the two recommended depths and an adaptive strategy. Methods: Thirty-eight animals (mass ~25kg) were sedated, anesthetized, intubated, and ventilated. Micromanometer pressure sensors were installed in the aorta and right atrium via the right femoral artery and vein. Coronary perfusion pressure (CPP) was calculated as aortic minus right atrial pressure. An ultrasonic flow probe was secured around the right common carotid. Biosignals were recorded at 1000Hz. Animals were then re-paralyzed, followed by a fentanyl bolus, and the endotracheal tube was occluded for 9min. Each was randomized to absolute (Group 1: 1.5in & 100/min), proportional (Group 2: 1/3 AP diameter & 100/min), or stepwise adaptive (Group 3: 1.5in & 100/min, adding 0.25in or 5/min q25s until CPP > 25mmHg) CC using a robotic compressor. Epinephrine (0.1mg/kg) and sodium bicarbonate (1mEq/kg) were given after 4min, followed by epinephrine (0.15mg/kg) q3min. Defibrillation (150J) was attempted after 5min; CPR discontinued after 20min. Mean arterial pressure (MAP), CPP and carotid blood flow (CBF) were calculated for the first 10 minutes of CPR and compared between groups with generalized estimating equations (GEE). Results: In GEE models, MAP, CBF and CPP did not differ between groups over the first 10 minutes of resuscitation. Each measure differed significantly over time (p Conclusion: In a swine model of asphyxial cardiac arrest, CC methods based on current guidelines and an additional adaptive approach did not differ hemodynamically.