SU1331486A1 - Photoplethysmograph - Google Patents

Abstract

The invention is intended to study the vascular reactions of a biological tissue to an irritant. The photoplethysmograph contains a current source 1, a common base 2 on which the first light source 3 is placed, two photodetectors 4 and 6 connected to a comparison circuit 7, and a recorder 8. In order to improve the accuracy of detecting vascular stimuli, the comparison circuit 7 is implemented as measuring device of the difference between the output signals of the photodetectors 4 and 6. The photoplethysmograph excludes signals that are not a consequence of the reaction of the vascular system of the biological tissue under investigation to the effect of the stimulus. 1 il. (f. C 00 CAJ 4 00 O5

Description

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The invention relates to medical technology, namely to photometric devices designed to study vascular-nix reactions of biological tissues to the action of stimuli.

The purpose of the invention is to improve the accuracy of the detection of vascular reactions to the stimulus.

A structural diagram of a photoplethysmograph is attached to the drawing.

The photoplethysmograph contains a current meter 1, a common base 2, on which the first light source 3 with the photodetector 4 and the second adjustable light source 5 with the photoreceiver 6 are placed, as well as the comparison circuit 7 and the recorder 8. The comparison circuit 7 is designed as a signal difference meter coming from the outputs of the photodetectors 4 and 6.

Current source 1 is connected to light source 3 and 5, two photodetectors.

4 and 6 are fixed with sources 3 and

5 lights on a common base 2. The outputs of the photodetectors 4 and 6 are connected to the inputs of the comparison circuit 7, the output of which is connected to the recorder 8.

The device works as follows.

With the help of current source 1, sources 3 and 5 of the light emit light fluxes, which, partially absorbed with the biological tissue of the studied areas of the body, reach the corresponding photodetectors 4 and 6. As a result, one input of circuits 1: 7 compares I

Electrical signals are received that correspond to changes in the optical density of the tissue under study, 1ce1 1c is found between the 3 CFiPTa source and the photoreceiver 4, and on the BTOpoii input, there are electric signals corresponding to the change in the optical density of the tissue source 5 and the photoreceiver b.

By adjusting the light intensity of the light source 5, due to the change in the magnitude of the signal received from the output of the photodetector 6, the value of this signal is equal to the signal from the photodetector 4. Since the comparison circuit 7 is made as a signal difference meter,

VNIIGO Order 3747/3

Random polygons pr-tie, Uzhgorod, st. Project, 4

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There is no electrical signal at the output of the comparison circuit 7. When an irritant is exposed to one of the sections of the test tissue, causing a change in its optical density, and as a result, the change in the signal from the photodetectors 4 and 6 to the corresponding inputs of the comparison circuit 7, the recorder 8 receives signals corresponding to those changes in optical density tissues that occurred only under the influence of razdragel.

Thus, in the photoplethysmograph, signals that are not a consequence of the reaction of the vascular system of the studied tissue of the body are excluded.

Q stimulates the stimuli, and also excludes signals caused by changes in the optical density of the tissue under the action of respiration, cardiac activity, etc. Introduction of the second light source 5 and placing it in series with the second photo receiver 6 allows increasing areas of tissue of this magnitude when

Q which exposure to stimuli on one of the sites does not cause vascular reactions in the second region As a result, a photoplethysmograph can be used to investigate weak vascular tissue responses in the body that are not distinguishable in well-known photoplethysmographs.

Claims (1)

Invention Formula 0 A photoplethysmograph containing a current source, a common base on which the first light source is located is connected to a current source, and two photodetectors connected to a comparison circuit, the output of which is connected to the recorder, that, in order to increase the accuracy of detection of vascular reactions to a stimulus, the comparison circuit is designed as a measurer of the difference between the output signals of photoelectric receivers, and in series with the second photon receiver it is placed on a common basis th a power source. Subscription five 0 five Circulation 595