Sequence of mitral valve motion and transmitral blood flow during manual cardiopulmonary resuscitation in dogs.

摘要: According to the thoracic pump model of cardiopulmonary resuscitation (CPR), heart serves as a passive conduit for blood flow from pulmonary systemic vasculature, necessitating an open mitral valve and anterograde transmitral during chest compression. To assess applicability this manual CPR techniques, two-dimensional echocardiograms were recorded right wall and/or esophagus in nine dogs (18 26 kg) CPR. The aortic opened with compression closed release, while tricuspid leaflets release. remained ventilation alone abdominal compressions. With onset brief, high-velocity (high-impulse) compressions, rapidly left ventricle was deformed, whether compressions applied sternum or mid-chest wall. reopened release each Left atrial echocardiographic contrast injections confirmed absence high-impulse its presence Failure leaflet approximation observed only when very low-velocity, prolonged (low-impulse) technique used, regions that did not directly overlie compressed. Consistent these observations, simultaneous recordings ventricular pressures sternal five (19 25 demonstrated peak mean ventriculoatrial pressure gradients 38.5 +/- 4.0 13.5 2.9 mm Hg, respectively, declined less impulsive observations made all but low-impulse are inconsistent model, support direct cardiac primary mechanism forward more techniques.