Abstract 15994: Relationship Between Right Atrial Pressure With Jugular Flow in an Asphyxial Model of Pseudo-Pulseless Electrical Activity in Swine

Introduction: The initial cardiac rhythms found during in-hospital respiratory arrests are typically either pulseless electrical activity (PEA) or asystole. Pseudo-PEA (p-PEA) often precedes true PEA and is characterized by a low-flow state in which cardiac contraction produces a non-palpable blood pressure. The purpose of the study was to characterize the relationships between venous and arterial pressures and the flows that drive brain perfusion in a hypoxic asphyxial model of p-PEA. Hypothesis: We hypothesized that during CPR right atrial pressure (RAP) would be related to jugular venous flow (JVF), and that aortic pressure (AOP) would be related to carotid flow, and that these relationships might change with time during p-PEA. Methods: Pseudo-PEA was induced via hypoxic asphyxiation in 12 domestic swine (~32 kg) with standard physiological monitoring. AOP and RAP were measured with solid state transducers placed in the thoracic aorta and right atrium. Blood flow was measured in the common carotid artery and jugular vein with ultrasonic flow probes. FiO 2 was reduced to 6% by mixing nitrogen into the airway. A target systolic blood pressure (SBP) of 40 mmHg was used to define p-PEA. The relationship between pressures and flows was determined with a Pearson correlation coefficient. Results: Overall, RAP was significantly negatively correlated with JVF ( r = -0.51, p r = 0.85, p Conclusions: In an asphyxial model of p-PEA, venous blood pressures and flows were negatively associated and the relationship varied as a function of time. Arterial pressures and flow were positively associated and the relationship varied less over time. These findings have implications for how and when chest compressions or other interventions should be applied when treating p-PEA.