Abstract 144: Importance of Release Velocity for Improved Hemodynamic Power at Varying Chest Compression Depths
Introduction: During cardiac arrest, chest compression (CC) release velocity or waveform has been suggested to be important for coronary perfusion and returning blood flow to the heart. A detailed investigation of the impact of changes in CC waveform on blood flows and pressures during prolonged CPR has yet to be thoroughly performed.
Methods: CPR hemodynamics in twelve domestic swine (~30 Kg) were studied using standard physiological monitoring. Flow probes were placed on the abdominal aorta, the inferior vena cava (IVC), the right renal artery and vein, the right common carotid and external jugular. Ventricular fibrillation (VF) was electrically induced. Mechanical CC were started after ten minutes of untreated VF. CC release was changed so that sternal recoil lasted 100 ms, 200 ms, or 300 ms. CC were delivered at a rate of 100 per minute and at a depth of 1.25 inch (n=9) and at a depth of 1.9 inch (n=3). Transitions between waveforms occurred every 2 min and were randomized.
Results: Analyses of the recorded hemodynamic power (power = flow*pressure) indicated that there was a significant difference in the amount of energy each CC waveform transferred to the blood in the IVC during 1.25 inch CC (100 ms = 0.021±0.008, 200 ms = 0.020±0.008, 300 ms = 0.017±0.006 watts, p < 0.001 for ANOVA) and during 1.9 inch CC (100 ms = 0.011±0.009, 200 ms = 0.011±0.008, 300 ms = 0.010±0.008 watts, p = 0.05 for ANOVA). Similar significant differences between waveforms were observed with absolute IVC flow, but not for coronary perfusion pressure.
Conclusions: CC release velocity at varying depths had a similar effect on hemodynamic power in the IVC with faster release being most advantageous. Care should be taken when performing CPR to ensure proper chest compression release.
- © 2013 by American Heart Association, Inc.