A device for determining skin blood flow

 

(57) Abstract:

The invention relates to medicine and is intended for functional diagnostics. The technical result is to increase the accuracy of measurements of the blood supply of the skin of man. The device includes a calibrator, sounding current generator, connected to a pair of electrodes, the transducer impedance - voltage indicator. New device is running the generator probe current schema generator stabilized by the amplitude of the rectangular pulses, each of the two electrodes is divided into current and potential and current electrodes are external to the potential. Potential electrodes serially connected transducer impedance - voltage, the first passive high-pass filter, the first active low-pass filter and an analog differentiator. In addition, applied additional pair of electrodes for removal of the action potentials, which are sequentially connected instrumental amplifier, the second passive high-pass filter, the second active low-pass filter and final amplifier. The calibrator is connected to the inputs of the first and second asset is the suspects, and can be used to determine the status of the blood supply of the skin of man.

A device for determining the pulse of blood, which contains the probe generator, two electrodes, item calibration, the impedance Converter in voltage, power, indicator, two peak-detector element subtraction, comparator, two elements And the Schmitt trigger, the counter register, an amplifier with adjustable gain, trigger and clock generator (SU N 1754064, MKI A 61 B 5/0295, publ. 15.08.92).

The disadvantages of this device are low resolution at the Desk cutaneous blood flow, which is mainly laminar in nature and, accordingly, small compared to the volume of blood, the amplitude of the pulse wave; inadequate allocation pattern of cutaneous blood flow from the General background of the blood supply to the inner tissues of the investigated area of the body such as the forearm or lower leg; no simultaneous independent information that defines hemodynamics, such as electrocardiogram for verification of curves and determination of the phase characteristics of the research object.

The technical result of the invention is Genie to decrypt them.

The technical result is achieved due to the fact that the device contains a calibrator, sounding current generator, connected to a pair of electrodes, connected in series Converter impedance-voltage indicator. As a generator, the excitation current used generator, made by the scheme generator stabilized by the amplitude of the rectangular pulses (frequency 400 kHz), each of the two electrodes is divided into current and potential and current electrodes when applied to a biological object are external to potential. Potential electrodes serially connected transducer impedance - voltage, the first passive high-pass filter, the first active low-pass filter and an analog differentiator. In addition, applied additional pair of electrodes for removal of the action potentials, which are sequentially connected instrumental amplifier, the second passive high-pass filter, the second active low-pass filter and final amplifier.

In Fig. 1 shows the block diagram of the device.

A device for determining skin blood flow comprises a generator 1 of the probing current rectangular formbeans - voltage, the output of which is connected to the indicator 5 and consistently included the first passive filter 6 of the upper frequencies, the first active filter 7 of the lower frequencies and analog differentiator 8. To a pair of electrodes 9 for removal of biopotentials connected instrumental amplifier 10, the output of which is serially connected to the second passive filter 11 of the upper frequencies, the second active filter 12 of the lower frequencies and final amplifier 13, the calibrator 14 is connected to the input of the active filter 7 and 12 of the lower frequencies.

The device operates as follows.

In the investigated part of the body impose a dielectric plate with two pairs of fixed electrodes - current 2 and 3 potential. A third pair of electrodes 9 for removal of the potentials placed on the chest (any bipolar lead electrocardiogram for monitoring). The outputs, which are the first filter 7 of the lower frequencies, the final formation of rogramme (curve, reflecting the volume of blood), analog differentiator 8, which form the first derivative of rogramme (differential curve, reflecting the rate of change of blood volume) and final amplifier 13 (curve electrocardiography form with stabilized amplitude, the order reduced the noise at the input of the Converter 4 impedance - voltage associated with the parasitic amplitude modulation of the useful signal uncontrollable fluctuations of the amplitude of the probe current is sinusoidal; the noise detection signal of rectangular shape fundamentally less noise detection signal sine wave - this leads to the improvement of the resolution of the device, respectively, and the improvement of measurement accuracy and legibility of curves, in addition, a large part of the energy spectrum of the rectangular signal is accounted for higher order harmonics, with the passage which surround the conductor formed by the studied area of the body such as the forearm, causing the appearance of skin effect, displacing the probe current to the external part of the volume of the conductor, i.e., to the patient's skin. To enhance the effect of a leakage of the excitation current in the tissue directly under the skin, the distance between the current electrodes is chosen less than the thickness of the investigated area of the body. Measures have been taken to get a picture of predominantly cutaneous blood flow, thus preventing exposure of the underlying tissue and arterial vessels largely olabl 6 and 7 improve readability curves, filtering respectively waves associated with breath, movement of the patient and high-frequency noise, do not carry useful information.

Instrumental amplifier 10 connected to a pair of electrodes 9, amplifies the potentials generated by the electric generator of the heart, the second filters 11 and 12 form the curve of the electrocardiogram, final amplifier 13 serves for adjustment of the output signal with the Registrar. The availability of this channel, you can solve the problem of verification of rheogram.

The calibrator 14 generates an exemplary sinusoidal signal to zoom entries recorded curves.

Using this device examined 30 patients with psoriasis, neurodermatitis, eczema, allowing to judge the state of the cutaneous blood flow before treatment and in the dynamics during and after therapy.

A device for determining skin blood flow containing the calibrator, the generator, the excitation current, is connected to a pair of electrodes, connected in series Converter impedance - voltage and light, characterized in that the generator of the probing current is made under the scheme generator stabilized by the amplitude of the pulses p which when applied to a biological object are external to potential, which are connected in series Converter impedance - voltage, the first passive high-pass filter, the first active low-pass filter and an analog differentiator, also apply to additional pair of electrodes for removal of the action potentials, which are sequentially connected instrumental amplifier, the second passive high-pass filter, the second active low-pass filter, and a final amplifier, and the calibrator is connected to the inputs of the first and second active low-pass filters.

 

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FIELD: medicine.

SUBSTANCE: method involves recording rheogram from feet and legs lifted and fixed at an angle of 45є. Then, rheogram is recorded on inhaling from legs directed vertically downward. Functional blood circulation reserve index is calculated as product of results of dividing and subtracting rheographic indices recorded under conditions of lifted and lowered extremities that means under conditions of functional venous system relief and venous hypertension, respectively.

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3 cl, 3 dwg

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1 ex, 1 tbl

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FIELD: medicine.

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2 cl, 3 tbl

FIELD: medicine.

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EFFECT: wide range of functional applications.

2 tbl

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