Development of Bionic Baroreflex System for Treatment of Orthostatic Hypotension due to Shy-Drager Syndrome

背景资料：方法和结果：仿生压力反射系统（bionic baroreflex system，BBS）是一个由计算机控制的负反馈系统，即人工血管中枢。它通过放置在主动脉弓中的微压计感知全身动脉压（SAP），并自动计算脉冲串的频率以刺激交感传出神经。我们选择腹腔神经节作为BBS的交感神经血管接口，因为内脏大神经支配的腹部血管床是动脉压的压力反射控制的主要效应机制。为了使该系统具有仿生性，人工血管中心（H_<BRP→STM>）的运行规则主动匹配于天然中心的运行规则。首先，我们确定了SAP的天然压力反射控制（H_<Native>）和SAP对腹腔神经节电刺激的反应（H_&lt;STM→SAP&gt;）的开环传递函数。我们从H_ /H_&lt;STM→SAP&gt;计算出H_&lt;BRP→STM&gt;<Native>，并将运算规则移植到计算机上。在10只压力反射衰竭大鼠中，我们评估了BBS在HUT诱导的快速降压过程中的表现。突然头高位倾斜使SAP在2秒内下降34±6 mmHg，在10秒内下降52±5 mmHg。另一方面，在BBS的实时执行期间，HUT后2秒时SAP下降为21±5 mmHg，10秒时下降为15±6 mmHg。这些动脉的BBS控制的反应是无法区分的，从那些由本机的压力反射。结论：我们的结论是，BBS振兴本机的压力反射功能与压力反射失败的大鼠。

Background : We developed a bionic technology for the treatment of baroreflex failure, and tested its efficacy in restoration of arterial pressure against head-up tilt (HUT) in rats with baroreflex failure.Methods and Results : The bionic baroreflex system (BBS) was a negative feedback system controlled by a computer, the artificial vasomotor center. It sensed systemic arterial pressure (SAP) through a micromanometer placed in the aortic arch and automatically computed the frequency of a pulse train to stimulate sympathetic efferent nerves. We selected the celiac ganglion as the sympathetic vasomotor interface for the BBS, because the abdominal vascular bed innervated by the greater splanchnic nerve is a major effector mechanism for the baroreflex control of arterial pressure. To make this system to be BIONIC, the operational rule of the artificial vasomotor center (H_<BRP→STM>) was actively matched to that of the native center. First, we identified the open-loop transfer functions of the native baroreflex control of SAP (H_<Native>) and the response of SAP to electrical stimulation of the celiac ganglion (H_<STM→SAP>). We computed H_<BRP→STM> from H_<Native>/H_<STM→SAP>, and transplanted the operational rule into the computer. In 10 rats with baroreflex failure, we evaluated the performance of the BBS during rapid hypotension induced by HUT. Abrupt head-up tilting dropped SAP by 34±6 mmHg in 2 sec, and by 52±5 mmHg in 10 sec. During real-time execution of the BBS, on the other hand, the fall in SAP was 21±5 mmHg at 2 sec, and 15±6 mmHg at 10 sec after HUT. These arterial responses controlled by the BBS were indistinguishable from those by the native baroreflex.Conclusions : We concluded that the BBS revitalized the native baroreflex function in rats with baroreflex failure.