Interposed abdominal compression-CPR: a case study in cardiac arrest research.

When the abdomen is compressed manually in counterpoint to the rhythm of chest compression, in the performance of interposed abdominal compression-CPR, artificial circulation is approximately doubled in animal experiments and in electronic models of the circulatory system. These studies suggest that external manual compression of the abdominal aorta acts like an intra-aortic balloon pump to increase aortic pressure, whereas external manual compression of the abdominal veins acts to prime the right heart and pulmonary vessels before the next chest compression. As a result, perfusion pressures and flows are increased. Several clinical studies of this technique have shown promising results including improved hemodynamics, resuscitation success, and survival. The history of interposed abdominal compression-CPR research suggests a number of principles that may be useful in the development of other new methods for the management of cardiac arrest, including the virtues of vigorously pursuing a new idea suggested by serendipitous observations, developing and refining a working hypothesis as to pathophysiologic mechanisms, working in interdisciplinary groups, refining a novel technique in stages as experience is gained, and recognizing the need for staged phase 1, 2, and 3 clinical trials in the context of the approximately ten-year gestation period from laboratory inspiration to clinical practice.