The total hospital information system described in this report is intended for infallible and quick information transfer to each section or department of the hospital as the information is entered under the order entry method by the doctors and nurses serving as information source. Being composed of three minicomputers (DEC PDP 11-70), the system allows for mutual back-up even when one of the computers fails. The system is also of a triangular network configuration which allows shared access to the data in each minicomputer system. MUMPS is used as the operating system language. The information services provided by the system cover almost all departments of the hospital, including the consultation room for outpatients, nurse stations, clinical test room, pharmacy, food supply, medical management, patient accounting, and other related sections. The order entry method has resulted in the following benefits: (1) Since information is transferred and processed ahead of the patient's, waiting time at the accounting window, blood collection station or pharmacy has been drastically reduced. (2) Inter-department information exchange has been improved in terms of accuracy and speed, eliminating missing of test order, number-of-meals totalizing errors, etc. (3) Missing of payment demand has been reduced, contributing to an increase in income. (4) Once information is entered into the system, it can be used repeatedly without the need for reentry. This allows for systematic operation of each department service and reduces overtime or other expenditure. The system also provides for periodical test order entry, access to prescription for the previous two times and the prescription information, registration of prescriptions for individual doctors and/or patients, urgent clinical test report, and its time-series display capabilities, thereby contributing to qualitative improvement of medical services.
Changes in mean heart rate have been used to describe changes in physical or mental load. In practice, heart rates are valuable criteria for the assessment of workload levels in exercise ECG test and etc. Changes in the variability of the instantaneous heart rate (cardiac arrhythmia or HRV) are more sensitive means of measuring workload. The heart rate may be identical, but the heart rate variability frequency differs. It is, therefore, important to undertake detailed examination of the cardiac arrhythmia as a time series. The aim of this paper is to assess the cardiac arrhythmia using practical time series of beat-to-beat variation or heart rate variability. Autoregressive model based on the stochastic theory for dynamic systems was applied to a time series of R-R intervals between two successive R-tops in the ECG to assess the heart rate variability in a quantitative way from the time series. The authors have introduced a new measure ARV defined by the ratio of residual variance for autoregressive models to the variance of the time series. Consequently, the ARV is the signal-to-noise ratio of the heart rate variation. In case of a purely random series, the ARV is reduced to zero; in case of a deterministic series, the ARV is reduced to 1. The exercise ECG tests (continuous progressive all-out treadmill runs) on 6 college students were studied. Changes in ARV usually appeared simultaneously with the onset of chest pain during physical exercise. Five different scores of assessment of the HRV were also computed and compared. The results show that the ARV based on the autoregressive model is very effective to assess the HRV.
A capacitive transducer has been developed for continuously measuring the vertical component of foot-forces during walking. The transducer is shaped like a insole and consists of two sub-transducer units, the front and rear. The outputs of the two units are summed up to give the total force exerted by the foot. Each unit has a multi-layered structure. The basic layer is a 2mm neoprene sponge sheet sandwiched between two 50μm copper foils. These, as a whole, form a capacitor. The other two layers comprise the driving shield and the static shield, which minimize the effect of stray capacitance and the power line noise, respectively. The transducer is thin (3.8mm), lightweight (90g) and flexible. Thus, it does not hinder the natural gait pattern. It can be attached to the shoe-sole easily by elastic bands and Velcro straps. The accuracy of the transducer is well within ±10% of the full scale. An error analysis has been made to clarify the change in sensitivity due to a localized load. The result is utilized to compensate for the inherent nonlinearity of the transducer units.
The present paper is concerned with realization of digital filter which has linear phase property suitable for filtering signals produced by human bodies. The signals from human bodies often suffer noises such as a slow fluctuation and line interference. The principle of the filter is relatively new using decimation (sampling rate decrease) and interpolation (sampling rate increase) effectively. This filter requires no multiplications and uses limited amount of memories to achieve economy. The proposed filter effectively eliminates very low frequencies such as slow fluctuations around a reference level and 50Hz and its harmonics. The filter has been simply realized with a conventional microprocessor Z-80. Also presented will be a few experimental results of the realized digital filter to compare them with the results produced by a conventional analog filter.
Total respiratory impedance, from 1 to 20Hz, has been obtained by a modification of the forced oscillation method, in which a complex wave pressure imposed on the respiratory system and the flow induced were processed by Fourier spectral analysis. Parameters of a 2-compartment model were estimated on the complex plane by a phasor method in which all elements were represented as phasors and its frequency characteristics were displayed as phasor loci. It appeared from this study that: (1) The resistance and inertance of an endotracheal tube were 2.2cmH2O/l/sec., 0.07cmH2O/l/sec2. respectively. (2) After correcting for the effect of the tube, large airway resistance and inertance, small airway compliance, parenchymal resistance and inertance during enflurane anesthesia were found to be as follows; 1.2cmH2O/l/sec., 0.07cmH2O/lsec2, 0.02l/cmH2O, 1.6cmH2O/l/sec., 0.04l/cmH2O respectively. Estimates obtained with added external resistance was consistent with predicted effects.
The relation between conductivity and fixed charge density (FCD) in the articular cartilage has been investigated. A measuring system of the resistivity of the articular cartilage has been developed on the basis of the four-point probe technique. The system was designed so as to measure the resistivity as a function of depth from the articular surface. There was a good agreement with the theoretical relation as shown herewith. The conductivity κ of the articular cartilage equilibrated in a pH 7.4 Ringer's solution was constant in all zones with a value of 6 to 10×10S/cm. On the contrary, κ of the articular cartilage equilibrated in distilled water varied distinctly, being low in the superficial zone (about 0.7×10S/cm) and high in the middle to deep zone (about 3×10S/cm). This was almost the same variation as that of the FCD which was measured by the tracer cation method, and a linear correlation between κ and FCD was found. The correlation coefficient was 0.88. As an application of the measuring system, compressive strain was applied to the articular cartilage equilibrated in distilled water and the resistivity was measured. From the change of the resistivity vs. depth relation with the strain, it was found that the superficial to middle zones were more compressible than the deep to calcified zone up to 20% strain.
In our previous paper, responses of the posture control system to forward-backward acceleration disturbances were examined. In the experiment reported in this paper, lateral acceleration disturbances were imposed upon a subject under condition of open and closed eyes. The sway angle of legs was measured by detecting the position of light emitting diodes attached to subject's leg using a position sensor system. The hip joint moment was measured by a force plate. These data formed the frequency response functions and coherence functions of the posture control system. The results indicate that, the visual system is effective in the low-frequency range. The results are also discussed from a view point of control engineering.