Transesophageal echocardiography to assess mitral valve movement and flow during long term cardiopulmonary resuscitation: How cardiac effects fade with time

Abstract Background Although the cardiac pump and the thoracic pump are the two main theories, the actual mechanisms of blood flow during Cardiopulmonary Resuscitation (CPR) in humans are still unclear. The aim of this study was to explore the relationship between the pump mechanism and time after cardiac arrest. Methods and results 20 patients with non-traumatic cardiac arrest were enrolled in this study. Transesophageal two-dimensional and pulse-doppler echocardiography were used during CPR. The duration of CPR was 60–80min if there was no return of spontaneous circulation (ROSC). We found: (1) The mechanisms of blood flow during CPR varied with time: the thoracic pump took the place of the cardiac pump after prolonged CPR in the same patient. (2) Peak transmitral flow (TMF) decreased (p Conclusions The pump mechanism changes over the course of prolonged CPR. Cardiac effect is an essential part of the pump at the beginning of cardiac arrest, but it faded with time, making the thoracic pump the dominate mechanism after prolonged CPR.