Abstract
BACKGROUND: Basic science research in cardiopulmonary resuscitation (CPR) is limited by challenges in obtaining haemodynamic data from models that simulate physiological processes. In this study, we assessed the morphology of the heart and lungs and calculated the ejection fractions of cardiac chambers during CPR using a virtual simulation. METHODS: A finite element model of a complete thorax, including internal organs, thoracic rib cage, spine, musculature, and a generic material representing soft tissues, was constructed from magentic resonance images of a man. Twelve chest compression simulations were performed with forces ranging from F = 50 to 600 N. During compression, lung and heart volumes were assessed, and the ejection fraction of each cardiac chamber was calculated. RESULTS: In our numerical simulations a compression depth of 5.06 cm was reached with a force of 450 N. At this depth, the right and left ventricular ejection fractions were 34.0% and 14.4%, respectively, while the right and left atrial ejection fractions were 22.1% and 24.2%, respectively. The cross-sectional area of the outflow tract decreased by 27.5% and 15.6% in the right and left ventricles, respectively. Lung volumes decreased by 193 cm(3) and 169 cm(3) in the right and left lungs, respectively, representing 11.2% of the total lung volume. CONCLUSION: The right ventricle exhibited the highest ejection fraction among the cardiac chambers, and the left atrium showed a higher ejection fraction than the left ventricle during CPR.