A computer system has been used to quantify the polygraphic sleep records. The system was applied to analysis of sleep stages, arterial oxygen saturation (SaO₂), pulmonary artery pressure (PAP), rib cage and abdominal motion in patients with chronic lung disease. Nocturnal oxygen desaturation (a 4 percent or greater fall from base line levels of oxygen saturation during sleep) was a common phenomenon in our subjects and was accompanied with elevation in pulmonary artery pressure. By means of calculating the correlations between SaO₂ and mechanical factors of breathing (rib cage and abdominal motion, phase lag of rib cage vs. abdominal motion, tidal volume, frequency of breathing), we found two cases: (1) oxygen desaturation lagged by about 7 breathes (25 seconds) behind reduced breathing, (2) increase of breathing lagged behind fall in SaO₂. We suggest that hypoventilation caused by mechanical deficiencies of breathing appears to be a primary factor in nocturnal oxygen desaturation, but that another mechanism (ventilation-perfusion mismatch e. g.) may be important in a certain disease. These techniques may be available to evaluate the contribution of mechanical factors of breathing to nocturnal oxygen desaturation.

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Micro-air-bubble in the extracorporeal circulation system produced by various sources such as artificial heart-lung system are usually eliminated by various type of blood filter. But little larger and smaller air-bubble than the mesh size of the filter can pass through it, and these air-bubble sometimes would be microembolic in peripheral circulation bed and cause the tissue damage. In this paper, we propose the new method using ultrasound which effectivelly eliminate micro-air-bubble without any blood damage. We theoretically and experimentally made clear that air bubbles in liquid grow in size due to the resonance phenomena or coalesce to form a large air bubble after drawing toward the pressure antinode or node and by approaching each other by the mutual attraction (Bjerkness forces) in the stationary weak sound field.
New method we proposed is based on these theory. Ultrasound source consists of the magnetostrictor is set on the bottom of the reservoir of the artificial lung. The frequency is 50kHz, pressure about 0.2atm. There are many micro-bubbles from 10μm to 30μm at the outlet of the blood filter in the extracorporeal circulation system before radiating the ultrasound, on the other hand, after radiating the ultrasound, these micro-bubbles are completely eliminated. It is obvious that small bubbles can pass through the mechanical blood filter grow in size in the weak sound field and result in being trapped in the node, antinode or blood filter. There is no damage such as hemolysis and no change in oxygen contents in blood by ultrasound radiation. This method is very useful in clinical use.

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It is of interest to characterize a dynamic function of muscle during movement, which is a non-stationary case, from surface EMG signals. This paper presents a new approach. This is based on a block algorithm in which a signal is divided in time into blocks and time-varying parameters are estimated in each block. A locally quasi-stationary processing, which is proposed here, is the method to estimate the parameters of an AR (autoregressive) model more precisely. It is assumed that an AR model represents a surface EMG generation system.
There have been many methods for the non-stationary analysis, for example, the synchronous averaging in stochastic approaches and the estimation methods of short-time power spectrum and system function by a locally stationary processing. However, the synchronous averaging method is restricted to the evoked responses of EEG or EMG and the locally stationary processing is not sufficient for essentially non-stationary signals.
In this paper, AR parameters were estimated from the surface EMG of masseter muscle by the locally quasi-stationary processing and the results were compared with the parameters by the conventional locally stationary processing. There are non-stationary intervals around evoked response or onset of masticatory EMG. AR parameters are linear prediction coefficients, reflection coefficients and poles.
As the results, the estimated characteristics of the time-varying parameters were reasonable in relation to the locus of lower jaw movement and the significant differences were showed in the non-stationary intervals.

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A Holter ECG system should have a flat transmission characteristic within the frequency range necessary to reproduce ECG waveforms. In order to specify the characteristics it is necessary to establish methods to measure the characteristics precisely. The phase characteristic of Holter ECG system is difficult to obtain because of the lack of zero-phase reference.
We devised a method to measure phase-shift characteristics in magnetic recording systems. In our method zero-phase reference is determined from a temporal plot of the frequency dependence of the phase-shift.
This method was successfully applied to a Holter ECG system and reasonable results were obtained.

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An automatic flow control system for cardio-pulmonary bypass (CPB) has been developed. The system consists of three micro-computers, one is used for pulsatile infusion pump, another for operational console, and the other for pressure and flow control. The micro-computer completely controls blood flow and pressure throughout CPB. At the beginning of CPB, the system starts with 26ml/kg/min of infusion flow and increases to 80ml/kg/min automatically and controls venous withdrawal flow to minimize the error between central venous pressure (CVP) and CVP preset point. Modified PI (Proportional-Integral) control algorithm with a sampling period of 3 seconds, is used for CVP controller. The results on 16 dog experiments indicate, more than 96% of total CPB period, this control system maintains CVP within ±1mmHg error of CVP preset point.

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An implantable telemetry epidural pressure sensor has been developed to monitor the intracranial pressure (ICP) after an operation in the field of cerebro-surgery. This sensor is embedded under the scalp to measure the intracranial pressure on dura mater.
This sensor has microbatteries, operates on FM-FM active telemetry using a semiconductor pressure sensor at the pressure receiving area. A subcarrier of 24kHz and the main carrier on 80MHz band are generated on both surfaces of a 14mm dia. alumina substrate. The power unit has two microbatteries. A reed switch installed at the top of the sensor is operated by an external magnetic field only when a monitoring. An antenna is embedded under the scalp to allow contact with the body.
Experiments on dogs and 8 cases of clinical applications were made and realized measurement of ICP with nonrestriction.

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Several methods for measuring eye movement have been studied. However, not so many research have been done concerning how two eye balls move when a human see an object with both eyes. In this paper we describe a method of measuring binocular movement precisely when a random-dot stereogram (RDS) is shown to a subject. The eye movement is measured by an image processing technique from the image sequence of binocular fundus taken by an infra-red television fundus camera. A hardware matching unit is employed in order to detect the movement of totally 800 right and left fundus images by detecting papillary positions with matching technique. As a result, time series of position data in horizontal and vertical directions are obtained.

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Characteristics of a suction effusion fluid which was transcutaneously obtained from skin surface by suction was investigated as a new sample for transcutaneous measurement of blood biosubstances. The collection method of the suction effusion fluid from a rabbit skin without any damage on the skin has been developed by the authors. The steady effusion rate of 0.4μl/min/cm² (skin) was obtained from the rabbit skin eliminated its stratum corneum by the suction pressure of 400mmHg. Comparative biochemical analysis between the suction effusion fluid and blood indicated that glucose and non protein nitrogens (NPNs) were contained with approximately the same concentration. The concentration of proteins and fats were found to remarkably small in the suction effusion fluid. These constituents of the suction effusion fluid may leads a actual long lifetime of biosensors. The blood glucose change was detected in the suction effusion fluid with 15 min delay in response. It was possible to explain this delay by the buffer effect of interstitial volume in the epidermal tissue though there are many mechanisms for the delay. This response time was approximately same as that reported by biosensors inserted in subcutaneous tissue. These results encouraged in attainment of a transcutaneous continuous monitoring of blood glucose and/or NPNs by this method.

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The conductance to the gas diffusion through the skin of normal human adults was measured by mass spectrometry at 37 to 45°C of skin surface temperature. Two transcutaneous gas samplers covered with membranes of different conductance were applied to the skin of the forearm and the gas flow rates from samplers were measured by a mass spectrometer. Skin conductance was calculated from the gas flow rates and the prior measurements of membrane conductance. The skin conductances (in 10^-9ml/sec·cm²·Torr) to O₂, N₂, and CO₂ at 37°C were 6.22, 1.87, and 76.8, respectively. At 43°C, the skin conductance increased up to 11.7, 4.77, and 130 for O₂, N₂, and CO₂, respectively. Change in skin thickness estimated from the results on the conductance suggests that the increase in blood perfusion within dermal papilla plays a major role in increasing the conductance with temperature.

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