Development of an artificial feedback system with abdominal electrical stimulation for treatment of orthostatic hypotension

我们研制了一个无创性人工反馈系统的原型，并评估了治疗直立性低血压的疗效。频率响应是可识别的，阶跃响应函数显示动脉压对刺激快速响应，并在20秒内达到稳态响应的90%。稳态增益为0.2 ± 0.07 mmHg/Hz。基于这些结果，Kp被设定为1.0，Ki被设定为0.01，使得伺服系统可以快速有效地衰减外部干扰的影响。该系统可使植物性直立性低血压患者的倾斜时间从2.3分钟延长到3.2分钟。用40 mmHg的空气裤压迫下肢可延长至4.4min。

We developed prototype of a noninvasive artificial feedback system with abdominal electrical stimulation, and evaluated an efficacy for treatment of orthostatic hypotension. The frequency responses were identifiable and the step response function showed arterial pressure quickly responded to the stimulation and reached 90% of the steady-state response in 20 seconds. The steady state gain was 0.2+-0.07 mmHg/Hz. On the basis of these results, Kp was set at 1.0, and Ki was set at 0.01, so that the servo system could quickly and effectively attenuate the effect of the external disturbance. The system could prolonged a tilting time in patients with autonomic orthostatic hypotension from 2.3 minutes to 3.2 minutes. Moreover, it could extend to 4.4 minutes by pressing lower limbs with air pants of 40mmHg.