Abstract 143: Impact of Chest Compression Quality and Positive Pressure Ventilation on Central Venous and Arterial Hemodynamics During Cardiac Arrest
Introduction: Current guidelines for chest compression (CC) quality and ventilation rate are based on survival outcomes and clinical consensus. However, a detailed investigation of how the guidelines optimize central blood flow and its interaction with other aspects of resuscitation efforts has yet to be performed. We hypothesized that the 2010 guidelines (2 inch compression depth) generate more central blood flow than the 2005 guidelines (1.25 in compression depth minimum), and that CC release velocity and positive pressure ventilation (PPV) phase, e.g inspiration vs. expiration, impact CC generated blood flows.
Methods: CPR hemodynamics in 12 domestic swine (~30 Kg) were studied using standard physiological monitoring. Flow probes were placed on the abdominal aorta (AA) and inferior vena cava (IVC). Ventricular fibrillation (VF) was electrically induced. Mechanical CC were started after ten minutes of untreated VF. CC release time was randomized between 100 ms, 200 ms, or 300 ms with transitions occurring every 2 min. CC were delivered for 54 min at a rate of 100 per minute and at a depth of 1.25 inch (n=9) or at a depth of 1.9 inch (n=3). Transitions between waveforms occurred every 2 min and were randomized. AA and IVC blood flows were aggregated by CC release velocity, CC depth, and ventilation phase for analysis.
Results: Deeper chest compressions resulted in significantly more net blood flow in the IVC and AA for all CC release velocities and ventilation phases (p < 0.05). Net blood flow was reduced during inspiration in the IVC for all CC release velocities and depths. PPV significantly reduced forward blood flow in the IVC during 1.25” CC and significantly increased backward blood flow in the IVC during 1.9” CC, both of which resulted in a reduction of venous return for all CC release velocities. Net blood flow was reduced during inspiration vs. expiration in the AA during 1.25” CC for all release velocities, but this effect was not seen at 1.9” CC.
Conclusions: 1.9” CC significantly improved net central blood flow. Positive pressure inspiration significantly reduced venous return. The improvement in IVC net flow at 1.9” CC was lessened by subtle reductions in CC release velocity and during the inspiration phase of PPV.
- © 2013 by American Heart Association, Inc.