Abstract 438: Synchronization of Chest Compressions During Pseudo Electro-Mechanical Dissociation Improves Blood Pressures Relative to Standard Chest Compressions

Abstract

Introduction: The treatment of pseudo electro-mechanical dissociation (P-EMD) with standard chest compressions leads to periods where the chest compressions and heart-beat are in phase and periods where the chest compression and heart-beat are out of phase. We hypothesized that synchronized chest compressions will improve hemodynamics relative to standardized chest compressions during P-EMD. Methods: Eight animals underwent surgical preparation and were exposed to hypoxia to induce P-EMD. The treatment period was divided into eight 45 sec epochs during which the P-EMD was left untreated or was treated with standard chest compressions or chest compressions synchronized to the R-wave in the ECG. For each epoch of CPR in each animal, we measured the rate of change in the hemodynamics over the last half of the epoch using linear regression. ANOVA modeling was used to compare changes in hemodynamics as a function of treatment. Results: The rate of change in coronary perfusion pressure (CPP), minimum right atrial pressure (RAPmin), and maximum right atrial pressure (RAPmax) was larger during synchronized compressions than during standard compressions or untreated P-EMD. The rate of change in AOPmin was larger during both treatments than during untreated P-EMD. Other differences in the rate of change were not detected between standard chest compressions and untreated P-EMD. Numerical results are shown in the table below. RAPmax decreased over time, while the other measures increased. Conclusions: Synchronized chest compressions improved several blood pressure metrics over time during P-EMD, while standardized chest compressions only improved AOPmin. While some of the changes are modest, they were sustained over 20 seconds, suggesting that continued delivery of synchronized chest compressions could result in clinically meaningful improvement in blood pressures. Table 1. ANOVA comparison of blood pressures as a function of treatment