Development of unconstrained cardiorespiratory and body movement monitor using piezoelectric polymer sensor.

我们已经开发了一种无约束和无创的心肺监护仪使用柔性压电电缆和薄膜组成的聚偏氟乙烯（PVDF）。PVDF换能器放置在床单上，使得受试者的身体围绕头部、胸部和腿部横向交叉，而不固定在皮肤上。通过引入I-V转换器将PVDF的电荷转换成比例电压，并通过A/D转换器以100 Hz的频率进行采样。采样数据被送入数字有限脉冲响应（FIR）滤波器。FIR滤波器的设计是通过选择0.8-30 Hz的通带频率限制用于记录心脏动作，0.2-0.5 Hz的限制用于呼吸，并通过整个奈奎斯特频率用于身体运动。当受试者处于仰卧位、俯卧位和侧卧位并穿着不同厚度的衣服时进行记录。为了检验该方法的有效性，将PVDF传感器确定的呼吸和心脏信号与呼吸流量计和心电图获得的信号进行比较。床上的每个传感器都能清楚地检测到呼吸信号，与受试者的姿势无关。在左心室射血期间发生的心源性弹道信号也可以由布置的传感器中的至少一个传感器检测到，但是当受试者穿着厚衣服时，它被遮蔽。结果表明，该系统使我们能够执行同时监测的呼吸和心率在睡眠期间，只要对象穿着平常的睡衣或汗衫。它有可能成为一种廉价，不受限制，并适用于家庭护理的人谁以前患有心肺功能障碍。

We have developed an unconstrained and noninvasive cardiorespiratory monitor using a flexible piezoelectric cable and film composed of polyvinylidene fluoride (PVDF). The PVDF transducers were placed on a bed sheet so that the subject's body is transversely crossed around the head, chest, and legs without being fixed on the skin. The charge of the PVDF was converted to a proportinal voltage by leading to I-V converter, and was sampled with the frequency of 100 Hz via A/D converter. The sampled data were fed into the digital finite impulse response (FIR) filters. The FIR filter was designed by selecting the passband frequencies limits from 0.8-30 Hz for the recording of the cardiac action, limits from 0.2-0.5 Hz for respiration, and passes whole Nyquist frequency for the body movement, respectively. The recordings were performed when the subject was in a supine position, prone, and lying on his side with wearing the dress of various thickness. To examine the validity of the method, respiratoly and cardiac signals determined by PVDF transducers were compared with those obtained by respiratory flow-meter and electrocardiogram. Every sensor arranged on the bed could detect the respiratory signals clearly independent of subject's posture. The cardiogenic ballistic signal occurring at the period of the left ventricular ejection could also be detected at least by one of sensors arranged, but it was obscured when the subject wore a thick dress. Results show that the system enables us to perform simultaneous monitoring of the respiratory and heart rates during sleeping as long as the subject wears usual pajamas or undershirt. It has the potential to become an inexpensive, unconstrained, and useful for home care of people who have previously suffered from cardiorespiratory disorders.