Clinical application of bionic baroreflex system

点击翻译按钮获取中文摘要

Background: We proposed a novel therapeutic strategy against central baroreflex failure: implementation of an artificial baroreflex system to automatically regulate sympathetic vasomotor tone, i.e., a bionic baroreflex system (BBS), and tested its efficacy in a model of sudden hypotension during surgery.Methods and Results : The BBS consisted of a computer-controlled negative feedback circuit that sensed arterial pressure (AP) and automatically computed the frequency (STM) of a pulse train required to stimulate sympathetic nerves via an epidural catheter placed at the level of the lower thoracic spinal cord. An operation rule was subsequently designed for the BBS using a feedback correction with proportional and integral gain factors. The transfer function from STM to AP was identified by a white-noise system-identification method in 12 sevoflurane-anesthetized patients undergoing orthopedic surgery involving the cervical vertebrae, and the feedback correction factors were determined with a numerical simulation to enable the BBS to quickly and stably attenuate an external disturbance on AP. The performance of the designed BBS was then examined in a model of orthostatic hypotension during knee joint surgery (n=21). Without the implementation of the BBS, a sudden deflation of a thigh tourniquet resulted in a 17±3 mmHg decrease in AP within 10 sec and a 25±2 mmHg decrease in AP within 50 sec. By contrast, during real-time execution of the BBS, the decrease in AP was 9±2 mmHg at 10 sec and 1±2 mmHg at 50 sec after the deflation.Conclusions : These results suggest the feasibility of a BBS approach for central baroreflex failure.