CS258679B1 - Two-channel magnetometer for face wall's motions measuring - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to a device for diagnosing chest wall movement, with electronic measurement of chest diameters, resp. breathing.

At present, different types of scans are used to measure chest wall movements, such as e.g. resistor transducers, cross-sectional strain gauges, etc., which are the most common part of elastic, usually rubber straps, encircling the chest. When breathing, the movements of the chest wall are transmitted through the straps of these straps to the transducers which transmit the movement to the equivalent! change in resistance or voltage.

The disadvantages of the measuring mechanisms using the above-mentioned types of sensors are the low accuracy and insufficient reproducibility of the measured values, which results in particular from the temporal instability of the mechanical and electrical properties of the sensors and straps, as well as the complications that arise when attaching chest straps, especially in the female population. In some cases, it is not sufficient for the diagnosis of respiratory muscle activity that these methods provide only one result, i. j. total value of chest circumference change.

FROM

The above-mentioned drawbacks are overcome by the solution according to the invention.

The principle of the device according to the invention consists in that in the opposite direction they are on the surface of the thoracic or respiratory tract. abdominal wall mounted receiving coils connected to input amplifiers and selective amplifiers with detectors connected to analog-to-digital converters with memories whose outputs are connected to digital-to-analog converters connected to a common amplifier whose output is equipped with a voltmeter.

The movement of the thoracic wall at the selected thorax diameter is measured by the magnitude of the induced voltage generated in the receiving coil from the rotationally symmetrical electromagnetic pole formed by the alternating current in the transmitting coil, which is positioned opposite to the receiving coil. Both coils are attached to the surface of the chest wall by adhesive intermediate rings. Since the magnitude of the induced electrical voltage is not linear in relation to the coil distance, the circuits of analog-to-digital converters, memories and digital-to-analog converters are used sequentially to linearize the given dependence.

The device allows non-invasive bosom to monitor objectively and continuously the movements of the chest wall mainly during breathing, in two independent, arbitrarily selected chest diameters. The instantaneous values of the measured values can be read directly on the display of the device, or continuously recorded on line and / or line. coordinate recorders. The spools used are small in size and weight and are attached to the chest wall surface by adhesive intermediate rings, which virtually eliminates other straps used. In addition, the device can also be used to monitor the movement of the abdominal wall.

The attached drawing shows a block diagram of the device.

The apparatus consists of two parallel-arranged, structurally identical transmission channels, each of which comprises successive connected harmonic signal sources 1, end amplifiers 2, to which transmit coils 3 are connected by flexible leads. the coils 3, 5 are elliptical in shape and self-supporting. The following electrical circuits are connected in series: selective amplifiers 7, detectors 8, analog-to-digital converters 9, memory 10, digital-to-analog converters 11, to which a common measuring amplifier 12 and a digital voltmeter 13 are connected.

In operation, the harmonic signal source 1 generates signals in the acoustic frequency band, which are amplified in the end amplifiers 2 so that the transmitter coils 3 are timed with a current of constant amplitude, thereby creating a rotationally symmetrical electromagnetic field around them. coils 5 electrical voltage. The amount of tension is proportional to the instantaneous distance of one pair of the transmit coil 3 and the receiving coil 5. All coils 3, 5 are shaped so that they can be easily fixed by adhesive intermediate rings 4 to the surface of the chest wall. The function of the following input amplifiers 6 and selective amplifiers 7 is to amplify only the signals of a given transmission channel. The detection of the signal in the detector 8 is followed by the analog-to-digital converter 9. The transition from the analog to digital signal in the memory block 10 allows correction of the non-linear course of the induced voltage dependence in the receiving coil 5. A digital-to-analog converter 11. The processing of the output signal takes place in the measuring amplifier 12 and evaluated by a digital voltmeter 13, or directly recorded on a recording device.

The device according to the invention measures two independent chest diameters in the range of 15 to 40 cm with an accuracy of + 0.2 cm. Verification measurements of the device prototype have shown that the device can be used to objectively monitor chest wall movement, mutual coordination of muscle groups in breathing, testing of diaphragm and other respiratory muscle performance, alcohol and anthropometric measurements on the human body. It turns out that the device may be able to measure, in an indirect manner, the instantaneous tidal volume, resp. to monitor breathing. In these circumstances, it is not necessary to use masks or mouthpieces, which has a positive effect on measurement hygiene, physiological adaptability and mobility of the person under investigation.

The device according to the invention can be used in physiotherapeutic rehabilitation departments, in paediatrics, pneumology, cardlology, neurology, orthopedics and occupational and physical education.

Claims (1)

Two-channel magnetometer for the measurement of chest wall movements, consisting of two parallel ordered, structurally identical transmission channels, each containing sequentially connected harmonic signal sources and terminal amplifiers with transmitter coils mounted on the thoracic surface, respectively. abdominal wall, characterized in that the receiving coils (5) connected to the input amplifiers (6) and the selective amplifiers (7) with detectors (8) connected to the analog-to-digital converters (9) are fastened by the rings (4) with memories (10), the outputs of which are connected to digital-to-analog converters (11i) connected to an amplifier (12), the output of which is provided with a digital voltmeter (13).