IN VIVO EVALUATION OF A HYBRID MOCK CIRCULATION LOOP INCLUDING A BAROREFLEX MODEL

• Published in: International journal of artificial organs 2011-08, Vol.34 (8), p.616-616
• Main Authors: Cuenca, E, Finochiaro, T, Fritschi, A, Jansen, S-H, Egger, C, Heinke, S, Holmannspoetter, O, Spillner, J, Autschbac, R, Leonhardt, S, Schmitz-Rode, T, Steinseifer, U
• Format: Article
• Language: English
• ISSN: 0391-3988

Objectives: A hybrid mock-circulation-loop (MCL) consisting of electrically controlled hydraulic elements and a software based model of the baroreflex autoregulation mechanism has been developed and constructed to evaluate control algorithms for mechanical circulatory support systems (MCS). The software detects an applied change in central venous pressure (CVP) and automatically adapts the MCL parameters to mimic the physiological response. The interaction of the developed software model and the MCL has been evaluated with in vivo experimental data from animal trials. Methods: Two rotary blood pumps (MEDOS DP) were integrated in the MCL in a total artificial heart setup, pumping fluid through a systemic and pulmonary circuit. An electro-mechanically variable venous reservoir was added to the previously presented MCL, to accurately change the CVP. Hereby venous vasoconstriction can be mimicked. Upon a change in aortic pressure, the computer model automatically adjusts the MCL parameters peripheral resistance and unstressed volume as it is done by the auto regulatory system. For in vivo validation, the native ventricles of the animal were replaced by the same rotary pumps and blood volume was varied by draining and infusing blood from and to the venous system. The baroreflex autoregulation response was measured through the changing MAoP. Results: For a change in CVP and a corresponding change in MAoP the model of the hybrid MCL replicates the baroreflex autoregulation mechanism and stabilizes the MAoP. The replicated response in the developed hybrid MCL and the in vivo setting show a similar behaviour. With this new function of the hybrid MCL, a physiologic autoregulatory response to blood loss or a postural change can be simulated. Conclusions: The hybrid MCL can be used as an in vitro tool to simulate physiological changes in the cardiovascular system. This facilitates the development of new control algorithms for mechanical circulatory support systems.