著者

岡田 正彦

出版者

一般社団法人 日本生体医工学会

雑誌

医用電子と生体工学 (ISSN:00213292)

巻号頁・発行日

vol.13, no.6, pp.356-359, 1975-12-30 (Released:2011-03-09)

参考文献数

7

被引用文献数

1

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Software techniques for solving two problems in monitoring the electrocardiograms of critically ill patients are described in this Paper.(1) Logical filter for detection of a QRS complex : High frequency components are centered around the peak-points of a QRS complex and the waveform is roughly symmetrical with respect to a vertical line through.the peak-point. These characteristics of the QRS complex are utilized in designing the filter. This filter distinguishes the QRS complex well from other parts of electrocardiograms and various noises.(2) Pattern recognition of a QRS complex with correlation coefficient : One typical QRS complex is selected and designated as “templet”. Subsequent QRS complexes are compared with this “templet” one by one. The degree of similarity to the “templet” is evaluated by a correlation coefficient. Without accurate detection of a QRS duration, 10 points before and after the peak of R-wave respectively (totalling 20 points) are regarded as one QRS complex (sampling rate : 250 points/second). Our method makes it possible to recognize ectopic beats automatically even if noises exist to some extent.

著者

村上 啓二 田中 弘富 増山 善明 吉川 昭

出版者

Japanese Society for Medical and Biological Engineering

雑誌

医用電子と生体工学 (ISSN:00213292)

巻号頁・発行日

vol.20, no.2, pp.113-116, 1982

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Effects of data compression, to save the processing time in the P-wave recognition program with the adaptive correlating filter (ACF), on the performance of the ACF has been studied.All QRS or QRST regions were eliminated from the record to compress ECG data.<BR>Two indices were adopted as criteria for evaluating the effects. One was derived on the basis of the performance characteristics of the ACF, while the other was the mean error probability in detecting P-waves by using the ACF.<BR>In result, it was shown that the method for data compression could make up for the loss of the P-wave information caused by the data reduction. So the data reduction proposed here makes data compression feasible with little deterioration of the ACF performance.

著者

吉澤 誠 馮 金山 竹田 宏 三浦 誠 山家 智之 片平 美明 仁田 新一

出版者

一般社団法人 日本生体医工学会

雑誌

医用電子と生体工学 (ISSN:00213292)

巻号頁・発行日

vol.26, no.2, pp.83-91, 1988-06-30 (Released:2011-10-14)

参考文献数

10

被引用文献数

8

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A new hemodynamic measurement system was developed by using the left ventricular assist device (LVAD) to estimate the cardiac function of the natural heart. The LVAD was placed between the left atrium and the aorta for the patient with deeply failed left ventricular pump function and driven by the pneumatic drive unit.In the personal computer system, an on-line identification method was implemented to estimate the coefficients of the autoregressive moving average (ARMA) model whose input and output were corresponding to the drive pressure of the drive unit and the pump flow from LVAD, respectively.Two driving modes of LVAD were compared with each other. One is the co-pulsation mode in which the systolic period of LVAD coincides with that of the natural heart, and the other is the counter-pulsation mode in which the systolic period of LVAD is followed by that of the natural heart.This comparison clarified that the capability of cardiac function of the natural heart could be quantitatively evaluated on the basis of the difference between two frequency responses derived from the coefficients of the ARMA model. This implies that the proposed method is useful for making a decision on weaning from LVAD in the clinical case.

著者

工藤 信樹 清水 孝一 松本 伍良

出版者

一般社団法人 日本生体医工学会

雑誌

医用電子と生体工学 (ISSN:00213292)

巻号頁・発行日

vol.23, no.3, pp.194-198, 1985-06-30 (Released:2011-10-14)

参考文献数

12

被引用文献数

3

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A new method of biotelemetry is proposed, which realizes nonrestrained acquisition of biological signals using the infrared light diffused out from animal skin. This technique is fundamentally different from conventional telemetry techniques which use radio-frequency electromagnetic waves.An optical transmitter which consists of some LED's is implanted beneath the skin. Biological information such as ECG signal is collected in vivo and the light emitted from the LED's is modulated by the signal. The light transmitted through the skin is strongly diffused and spread out in a wide angle. The light is collected by the remotely located optical receivers and the biological information is obtained by demodulating the signal. Thus, the biological information in vivo is obtained without restraining the object with cables or optical fibers.In order to verify the possibility of the above technique, a system, which obtains an ECG from laboratory animals, has been developed. An infrared light was chosen due to its invisibility and high transmittance through the skin. Considering the stability of the communication link and the power consumption of the implanted transmitter, PFM (Pulse Frequency Modulation) technique was used. Using the system, the transcutaneous ECG telemetry was performed successfully.In the experiment, the indirect light reflected and scattered by the walls, the ceiling and the floor was shown to be useful in the optical telemetry. Light transmission patterns through the skin of a mouse were measured. The results suggest the possibility of telemetry even from the deep part of the body cavity.It is concluded that recent progress of optical and electronic technologies have reached the point, where transcutaneous optical telemetry of biological signals has become practically possible.

著者

岩谷 眞宏

出版者

一般社団法人 日本生体医工学会

雑誌

医用電子と生体工学 (ISSN:00213292)

巻号頁・発行日

vol.20, no.4, pp.249-255, 1982-08-30 (Released:2011-03-09)

参考文献数

20

被引用文献数

3

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Using the thermograph and other instruments, a new and noninvasive method of evaluating the skin blood flow rate has been developed. Supply of heat to the skin depends on heat transportation by blood flow, on conduction from deep tissue and on the metabolic production in the skin. On the other hand, the skin loses the heat to surroundings through radiation, evaporation and convection. The heat in each case can be expressed as a function of temperature. In a comfortably air-conditioned room, there is little change in the skin temperature. Therefore, the heat flowing into the skin is presumed to equilibrate the heat flowing out. Rearranging these equations, the formula for the skin blood flow rate is obtained. For calculation, skin temperature, core temperature, ambient temperature and diameter of the leg were measured and other figures were postulated on the basis of anatomical or physiological data. Skin temperature was measured using a thermograph. Core temperature was measured by the use of deep body thermometer. Both procedures are noninvasive. Six points in a patient were subjected to the measurement. These included 10cm above the knee, 10cm below the knee and dorsum of the foot on each limb.The skin blood flow rates calculated by this method were found to be15.0±9.7ml/1009/min (n=88) on the thigh, 14.5±10ml/100g/min (n=85) on the leg and 13.3±11.0ml/100g/min (n=87) on the foot. These values corresponded well with the values reported by others, who used the plethysmographic or clearance method. The relationship between skin temperature and skin blood flow was exponential as has been pointed out by Montogomery and others. After unilateral lumbar sympathectomy in thirteen cases, the skin blood flow rate and the skin temperature on the side operated on showed statistically higher values than on the side not operated on. Especially the skin blood flow rate on the foot was higher by 50%. This fact was also compatible with previous studies on the effects of sympathectomy.As a. result, this noninvasive method of evaluating the skin blood flow is practically acceptable and will be a new addition to diagnostic armamentarium for various diseases.

著者

川端 信男

出版者

一般社団法人 日本生体医工学会

雑誌

医用電子と生体工学 (ISSN:00213292)

巻号頁・発行日

vol.14, no.4, pp.289-295, 1976-08-30 (Released:2011-03-09)

参考文献数

9

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Some geometrical optical illusions are analyzed in terms of the perceptual field. Psychological distance is introduced which is different from physical distance, and this difference explains theillusion.A theory is proposed which represents the psychological distance as a function of the field potential induced by the stimulus figure. By defining the psychological distance and line, the straight line and the length in the figure can be determined, and geometrical optical illusions cam be explained as distortions of the metric of the perceptual field.

著者

中山 昭雄

出版者

一般社団法人 日本生体医工学会

雑誌

医用電子と生体工学 (ISSN:00213292)

巻号頁・発行日

vol.15, no.3, pp.157-163, 1977

著者

竹前 忠 東 好宏 小杉 幸夫

出版者

日本エム・イー学会

雑誌

医用電子と生体工学 : 日本ME学会雑誌 = Japanese journal of medical electronics and biological engineering : JJME (ISSN:00213292)

巻号頁・発行日

vol.38, no.3, pp.246-250, 2000-09-10