Efficacy of interposed abdominal compression-cardiopulmonary resuscitation (CPR), active compression and decompression-CPR and Lifestick CPR: basic physiology in a spreadsheet model.

This study was undertaken to understand and predict results of experimental cardiopulmonary resuscitation (CPR) techniques involving compression and decompression of either the chest or the abdomen. Simple mathematical models of the adult human circulation were used. Assumptions of the models are limited to normal human anatomy and physiology, the definition of compliance (volume change/pressure change), and Ohm's law (flow = pressure/resistance). Interposed abdominal compression-CPR, active compression and decompression of the chest, and Lifestick CPR, which combines interposed abdominal compression and active compression and decompression, produce, respectively, 1.9-, 1.2-, and 2.4-fold greater blood flow than standard CPR and systemic perfusion pressures of 45, 30, and 58 mm Hg, respectively. These positive effects are explained by improved pump priming and are consequences of fundamental principles of cardiovascular physiology.