Tamura T, Sato K, Togawa T
Department of Electrical and Electronic Engineering, Yamaguchi University, Japan.
IEEE Trans Biomed Eng. 1992 Dec;39(12):1274-82. doi: 10.1109/10.184703.
An apparatus for monitoring prolonged measurement of oxygen uptake without discomfort has been developed. The system is based on the open flow-through principle. The subject wears a hood through which air is drawn by an exhaust blower. Oxygen concentration is kept constant by a servo-controlled blower, so that flow rate is essentially proportional to oxygen uptake. The flow rate of the main stream is measured by a time-of-flight flowmeter located in the exhaust hose. Oxygen concentration is measured by a limiting-current oxygen sensor. The signals representing flow rate and oxygen concentration are digitized and stored in a memory. All of the equipment is assembled in a small package (wt = 3 kg) which the subject carries on his back. The memory chip is removed from the portable device after each experiment. Data are transferred from the memory to a microcomputer and then an oxygen uptake trend is estimated. Response of the system to a step input is about 30 s. Compared with a commercially available oxygen monitoring system (Magna 88, P. K. Morgan Ltd., Rainham, UK), the maximum difference was 0.15 L/min within an oxygen uptake range of 0.25-2.3 L/min. Thus, the measurements made with our portable device agree with the results obtained using the conventional method.
已开发出一种用于在无不适情况下监测长时间摄氧量测量的装置。该系统基于开放流通原理。受试者佩戴一个头罩，排气扇通过头罩抽吸空气。氧气浓度由伺服控制的风扇保持恒定，因此流速基本上与摄氧量成正比。主流的流速由位于排气软管中的飞行时间流量计测量。氧气浓度由极限电流氧气传感器测量。表示流速和氧气浓度的信号被数字化并存储在存储器中。所有设备都组装在一个小包装（重量 = 3 千克）中，受试者背在背上。每次实验后，将存储芯片从便携式设备中取出。数据从存储器传输到微型计算机，然后估计摄氧量趋势。系统对阶跃输入的响应约为 30 秒。与市售的氧气监测系统（Magna 88，P.K. Morgan Ltd.，英国雷纳姆）相比，在 0.25 - 2.3 L/min 的摄氧量范围内，最大差值为 0.15 L/min。因此，我们便携式设备的测量结果与使用传统方法获得的结果一致。
