JP4502537B2 - Bath sphygmomanometer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bathtub sphygmomanometer that measures a blood pressure of a bather in real time.
[0002]
[Prior art]
As a method for measuring a person's blood pressure, a method using a general cuff type sphygmomanometer is widely known. The cuff method is a method by which anyone can measure blood pressure if attention is paid to the height of the arm, the attachment position of the cuff, and the like.
[0003]
In addition, by combining pulse oximetry sold under the trade name “Finapress” of Ohmeda with a pneumatic cuff, the cuff pressure is negatively fed back so as to maintain a constant infrared absorbance near the artery of the finger. There is a method of measuring blood pressure by the zero method. The measurement principle of this measurement method is to see the time change of blood pressure as the time change of the amount of blood flowing in the human body. Specifically, in order to see the change in blood volume over time, infrared light is emitted toward the human body from a light emitting unit provided outside the human body, and the light is scattered by the transmitted light or bones and emitted outside the human body. By receiving the scattered light received by the light receiving unit, the time change of the intensity of infrared light absorbed by hemoglobin in the blood flowing inside the human body is measured. Therefore, when there is a lot of blood present on the optical path of infrared light, the amount of absorbed infrared light increases, and when there is little blood, the amount of absorbed infrared light also decreases. Here, since the blood vessel diameter changes due to the fluctuation of the blood pressure value for each pulse, the amount of blood existing on the infrared optical path also changes, so the blood pressure value is determined by measuring the change in the received infrared light intensity. Can be sought.
[0004]
Alternatively, there is a method of directly measuring blood pressure by inserting a blood pressure transducer into the artery.
[0005]
[Problems to be solved by the invention]
However, the method of directly inserting the blood pressure transducer into the artery can measure blood pressure most accurately, but it is a method that invades the human body, so it involves pain and bleeding, especially during bathing Was inappropriate due to the risk of infection. In addition, it is impossible to require a general bather to insert a blood pressure transducer directly into the body.
[0006]
The cuff type sphygmomanometer has the advantage that even an amateur can easily wear it, but it is necessary to restrain the bather and apply a burden to apply pressure to the measurement site of the bather with a pump, etc. In addition, there is a problem that the cuff attachment / detachment and the cuff handling during measurement are troublesome.
[0007]
In addition, the method combining pulse oximetry and cuff is measured on the premise that the capillaries of the measured part do not significantly expand or contract from the start to the end of measurement, so during bathing As a method for measuring the blood pressure of a bather, there is a problem of lack of accuracy.
[0008]
This invention is made | formed in view of said problem, The objective is to provide the bathtub blood pressure meter which measures the exact blood pressure of a bather non-invasively in real time.
[0009]
The first characteristic configuration of the bathtub sphygmomanometer according to the present invention for solving the above-described problem is a bathtub sphygmomanometer that measures the blood pressure of a bather as described in claim 1 of the claims. A bath sphygmomanometer for measuring a blood pressure of the bather, wherein the heartbeat measuring means measures the heartbeat timing of the bather, and the pulse wave measurement measures the pulse wave at the measurement site on the body surface of the bather Means, a propagation time deriving means for comparing the pulse wave and the heartbeat timing, and deriving a propagation time of the pulse wave from the heart to the measurement site, and the pulse wave from the heart to the measurement site An average for deriving the propagation velocity of the pulse wave from the propagation distance and the propagation time, and deriving an average blood pressure value at the measurement site based on a predetermined first relationship between the pulse wave propagation velocity and the blood pressure value and blood pressure deriving means, by said pulse wave measuring means An intermediate value of the determined pulse wave is specified as the average blood pressure value derived by the average blood pressure deriving means, and a second relationship that is a relationship between the pulse wave and the blood pressure value, and the specified Blood pressure value deriving means for deriving the highest blood pressure value and the lowest blood pressure value at the measurement site from the pulse wave measured by the pulse wave measuring means based on the average blood pressure value, the blood pressure value deriving means The difference between the first pulse wave at the measurement site measured under atmospheric pressure and the second pulse wave at the measurement site measured under a second pressure different from the atmospheric pressure, and the atmospheric pressure By deriving the second relationship that is a relationship between a pulse wave and a pressure from a pressure difference with the second pressure, and converting the pulse wave into the blood pressure value, Mean blood pressure value, the highest blood pressure value and the above There is a point to derive the low blood pressure values.
[0011]
In order to solve the above problems, a second characteristic configuration of the bathtub sphygmomanometer according to the present invention is the pulse wave in addition to the first characteristic configuration as described in claim 2 of the column of the claims. The measurement means includes a light emitting unit that irradiates light to the measurement site, a light receiving unit that receives the light scattered by the bather, and the pulse based on a temporal change in received light intensity in the light receiving unit. And a first calculation means for deriving a wave.
[0012]
The third characteristic configuration of the bathtub sphygmomanometer according to the present invention for solving the above-mentioned problem is as described in claim 3 in the column of the claims, in addition to the first or second characteristic configuration, The heart rate measuring means includes a plurality of electrodes provided on the inner wall of the bathtub, a transmission means for transmitting each electric signal induced to the electrodes to the outside, an amplifying means for amplifying the electric signal, and the amplified And a second calculation means for processing the electrical signal to derive the heartbeat timing.
[0013]
The operation and effect will be described below.
According to the first characteristic configuration of the bathtub sphygmomanometer according to the present invention, the heartbeat measuring means measures the heartbeat timing of the bather, and the pulse wave measuring means is at a measurement site on the body surface of the bather. The pulse wave is measured, the propagation time deriving means compares the pulse wave and the heartbeat timing, derives the propagation time of the pulse wave from the heart to the measurement site, and the average blood pressure deriving means is the heart blood pressure deriving means from the heart. The propagation speed of the pulse wave is derived from the propagation distance of the pulse wave to the measurement site and the propagation time, and the average blood pressure at the measurement site is determined based on the relationship between the predetermined pulse wave propagation velocity and the blood pressure value. A blood pressure value deriving unit that calculates a blood pressure value at the measurement site based on the predetermined second relationship between the amplitude of the pulse wave and the amplitude of the blood pressure value, and the average blood pressure value. Can be derived. Here, the second relation is a relational expression that can convert the measured pulse wave scale into a blood pressure value scale. Therefore, the blood pressure value of the bather can be measured non-invasively and without burdening the bather, and by a simple method. Further, even if the pulse wave measuring means is attached, the blood pressure value measurement can be easily performed without causing a problem of handling like a cuff provided with a pump. The distance from the heart to the measurement site can be derived from the height, weight, etc. of the measurement subject. Or, mark the position of the heart and the position of the measurement site on the inner wall of the bathtub with a predetermined interval, and instruct the bather to lean on the marked position, know the distance from the heart to the measurement site You may comprise so that it can do.
[0014]
Here, the waveform of the pulse wave at the measurement site depends on the heartbeat timing in the heart, but the peak of the pulse wave appears with a delay from the heartbeat timing in proportion to the distance from the heart to the measurement site. Accordingly, the propagation speed of the pulse wave can be derived from the delay time from the heartbeat timing of the waveform peak of the pulse wave and the distance from the heart to the measurement site. It is known that a proportional relationship is established between the propagation speed of the pulse wave and the blood pressure value, and the average blood pressure at the measurement site can be derived from the derived propagation speed of the pulse wave. Therefore, since the maximum value and the minimum value of the pulse wave can be associated with the maximum value and the minimum value of the blood pressure, the blood pressure value waveform at the measurement site is derived by converting the average value into the average blood pressure value. Can do.
[0015]
Furthermore, the difference between the first pulse wave under atmospheric pressure (before pressurization) and the second pulse wave under second pressure (after pressurization) with respect to the measurement site, and the pressure difference between the atmospheric pressure and the second pressure, From this, the relationship between the pulse wave and the pressure can be derived, the maximum and minimum values of the amplitude of the pulse wave correspond to the maximum and minimum blood pressure values, and the intermediate value of the amplitude of the pulse wave is intermediate Considering the correspondence with blood pressure values, the scale of the amplitude of the pulse wave can be converted to the scale of pressure (blood pressure value). As a result, not only the average blood pressure value obtained earlier, but also the maximum blood pressure value and the minimum The blood pressure value can also be accurately derived.
[0016]
According to the second characteristic configuration of the bathtub sphygmomanometer according to the present invention, the pulse wave measuring means includes a light emitting part and a light receiving part, and when the infrared rays irradiated from the light emitting part enter the human body, blood Infrared light is absorbed by the hemoglobin therein, and the amount of absorption is proportional to the amount of hemoglobin present on the optical path of the infrared light. Therefore, when the received light intensity is small, it means that there is a large amount of hemoglobin that contributes to absorption of infrared rays, that is, the amount of blood is large, and when the received light intensity is large, the amount of hemoglobin that contributes to absorption of infrared rays is small, That is, it means that the blood volume is small. Accordingly, by measuring the temporal variation of the received light intensity, it is possible to measure the temporal variation of the blood volume at the measurement site, that is, the pulse wave.
[0017]
According to the third characteristic configuration of the bathtub sphygmomanometer according to the present invention, the heartbeat measuring means noninvasively measures the heartbeat timing obtained from the bather's, for example, the peak of the R wave of the electrocardiogram waveform during bathing. The ability to avoid physical and mental burdens on bathers, and accurate heart rate measurement in normal times, that is, accurate blood pressure measurement can do.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The bathtub sphygmomanometer 1 according to the present invention includes a heart rate measuring means 2, a pulse wave measuring means 3, a propagation time deriving means 4, an average blood pressure deriving means 5, and a blood pressure value deriving means 6. Here, the pulse wave measuring means 3 receives the light emitting means 7 for irradiating light to the measurement site on the body surface of the bather, and the transmitted light transmitted through the bather or the irradiated light scattered by the bather. Light receiving means 8 and a first calculation means for deriving a pulse wave waveform based on a temporal change in the received light intensity in the light receiving means 8 or the absorbed light intensity by the bather. The heartbeat measuring means 2 includes a plurality of electrodes 10a and 10b provided on the inner wall of the bathtub, transmission means 11a and 11b for transmitting the respective electric signals induced to the electrodes 10a and 10b to the outside, and the electric signals. Amplifying means 12 for amplification and signal processing of the amplified electric signal to derive a bather's heartbeat timing (specifically, heartbeat timing time-series data obtained from the peak of the R wave of the electrocardiographic waveform) 2nd calculating means 13 to be provided. The propagation time deriving means 4, the average blood pressure deriving means 5, the blood pressure value deriving means 6, the first calculating means 9, and the second calculating means 13 are configured by a single signal processing means 14 realized using a CPU or the like. be able to.
[0019]
Hereinafter, a method for measuring a pulse wave will be described with reference to FIG.
As shown in FIG. 2, the pulse wave is measured by the pulse wave measuring means 3 by attaching a wristband 17 having a light emitting means 7 and a light receiving means 8 to a human body (here, a wrist of a bather) and performing a first calculation. This is performed by performing a pulse oximetry method (infrared absorbance measurement method) under the control of the means 9. It should be noted that the wearing part (measurement part) of the wristband 17 is under atmospheric pressure. Further, the wristband 17 and the first calculation means 9 are connected using a conductor that does not restrain the movement of the bather as much as possible, and as a result, the bather is not aware that the pulse wave is being measured. Can be configured.
[0020]
The light emitted from the light emitting means 7 (here, infrared light) is absorbed by an infrared light absorption factor (such as hemoglobin in the blood) inside the human body, or is further scattered by a bone or the like and released outside the human body. The The light receiving means 8 may be arranged to receive the reflected light or may be arranged to receive the transmitted light. Therefore, the light emitted outside the body is received by the light receiving means 8, and as a result, the temporal change in the intensity of absorbed light by the human body as shown in FIG. 3A is derived.
[0021]
The time change of the absorbed light intensity shown in FIG. 3 (a) corresponds to the time change of the blood volume existing on the optical path of the light emitted from the light emitting means 7 and received by the light receiving means 8, and as a result. The waveform of the bather's pulse wave proportional to the waveform of the absorbed light intensity can be obtained. In particular, by attaching the wristband 17 so that there is an artery on the optical path from the light emitting means 7 to the light receiving means 8, a temporal change in the amount of blood flowing through the artery, that is, a waveform of a pulse wave is obtained. The obtained pulse wave waveform is output from the first calculation means 9. The amplitude of the pulse wave signal waveform is proportional to the amplitude of the blood pressure value (difference between the maximum blood pressure value and the minimum amplitude value), and the intermediate value of the amplitude of the pulse wave signal waveform corresponds to the average blood pressure value. The absolute blood pressure value cannot be determined from the light intensity scale).
[0022]
Next, a heartbeat measuring method will be described.
As shown in FIG. 1, the means 11a and 11b for transmitting an electrical signal indicating the body surface potential of the bather induced to at least two electrodes 10a and 10b through water by the heartbeat measuring means 2 used here are used. FIG. 3B shows a result of differential amplification of the electrical signals induced to the electrodes 10a and 10b by the amplification means 12 and processing of the amplified electrical signals by the second calculation means 13. An electrocardiographic signal (electrocardiographic waveform) of the bather as shown is obtained. The obtained electrocardiographic waveform is output from the second calculation means 13. As the electrodes 10a and 10b, an electrode embedded in the inner wall surface of the bathtub or a metal handrail usually mounted in the bathtub can be used.
[0023]
Next, by comparing the pulse wave at the measurement site (here, the wrist) of the bather shown in FIG. 3A and the heartbeat timing of FIG. 3B, from the bather's heart to the measurement site. The pulse wave propagation time Δt can be obtained. Furthermore, the distance from the heart to the measurement site can be derived with reference to the height, weight, etc. of the bather. Alternatively, mark the position of the heart on the inner wall of the bathtub (the position where the back rests) and the position of the measurement site that is a predetermined distance away from it, and instruct the bather to lean on those positions. By maintaining the distance from the heart to the site to be measured, the distance can always be kept constant.
[0024]
Therefore, the mean blood pressure deriving means 5 can derive the propagation speed of the pulse wave from the heart to the measurement site using the propagation time Δt and the propagation distance of the pulse wave from the heart to the measurement site. In order to derive a highly accurate propagation speed, an average value of a plurality of propagation times Δt measured during a predetermined period may be taken.
[0025]
Further, it is known that the relationship shown in FIG. 4 is established between the propagation speed of the pulse wave and the average blood pressure, and the average blood pressure deriving means 5 can derive the average blood pressure value at the measurement site. it can. Therefore, from the average blood pressure value derived using the blood pressure value deriving means 6, the intermediate value of the amplitude of the pulse wave signal waveform shown in FIG. 3A can be specified by the average blood pressure value. The scale of the vertical axis (absorbed light intensity) of the graph shown in a) is determined between the amplitude of the absorbed light intensity (pulse wave signal waveform) and the amplitude of the blood pressure value (difference between the maximum blood pressure value and the minimum amplitude value). The maximum blood pressure value by converting to a blood pressure value scale using the predetermined proportional relationship, or the proportional relationship derived by actually measuring, and the above average blood pressure value specified on the graph of absorbed light intensity A minimum blood pressure value can also be derived. In addition, since the relationship between the pulse wave propagation speed and the average blood pressure may change with the passage of time depending on the person, the pulse wave propagation speed between the two points (the heart and the measured site) is periodically It may be necessary to measure the average blood pressure of the measurement site and update the relationship between them as shown in FIG.
[0026]
As described above, basically, bathtub sphygmomanometer 1 blood pressure during bathing bather noninvasive using, it measured in a simple way for and bathing himself.
[0027]
Then, the scale of the absorbed light intensity in the graph shown in FIG. 3A is used to determine the relationship between the amplitude of the pulse wave signal waveform and the amplitude of the blood pressure value (difference between the maximum blood pressure value and the minimum amplitude value) and the average blood pressure. The maximum blood pressure value and the minimum blood pressure value were also derived by converting the values into a blood pressure value scale. However, the amplitude of the pulse wave signal waveform and the amplitude of the blood pressure value (the difference between the maximum blood pressure value and the minimum amplitude value) used when converting the amplitude of the pulse wave signal waveform (scale of absorbed light intensity) to the scale of blood pressure value. ) May cause an error. In other words, by calculating the amount of change in the intensity of absorbed light relative to the amount of change in pressure applied to the measurement site, the amplitude of the pulse wave signal waveform (scale of absorbed light intensity) can be more accurately converted to a blood pressure value scale. Can do. The method will be described below.
[0028]
In the method described below, a known pressure is applied to the measurement site and two absorption light intensity graphs (pulse wave waveforms) are measured, whereby the amplitude of the pulse wave signal waveform (absorption light intensity) is measured. This is a method for accurately converting a scale) into a blood pressure value scale. As a method for applying the pressure, a case where a known pressure is applied using a cuff and a case where the pressure is applied by submerging the measurement site at a known water depth (known water pressure) can be taken.
[0029]
When submerging the part to be measured to a known depth, mark the measurement point on the inner wall of the bathtub in advance, and use the water level sensor that is used for the automatic hot water function of the bathtub. By automatically deriving the water depth, the pressure applied to the measurement site is also automatically derived.
[0030]
First, the waveform of the pulse wave shown in FIG. 3A can be measured under atmospheric pressure in the same manner as described above. Next, sink the bather's measurement site to a known water depth while wearing the wristband 17, or apply a similar pulse wave with a known pressure applied to the measurement site using a cuff. Measure the waveform. In FIG. 5, the waveform of the pulse wave after application of pressure and the waveform of the pulse wave before application are shown on the same scale.
[0031]
As shown in FIG. 5, the amplitude of the absorbed light intensity (pulse wave signal waveform) is proportional to the amplitude of the blood pressure value (difference between the maximum blood pressure value and the minimum amplitude value), and the intermediate value of the amplitude of the absorbed light intensity is the blood pressure value. It corresponds to the mean blood pressure value of the amplitude. From FIG. 5, it is possible to compare the absorption light intensity (B) before pressurization and the absorption light intensity (A) after pressurization with respect to the measurement site, and the peak value when two pulse wave waveforms are compared ( The peak of the maximum blood pressure value and the peak of the minimum blood pressure value), and the amount of change in the intermediate value of the amplitude (scale of absorbed light intensity) correspond to the applied known pressurization value (pressure scale). Therefore, the amplitude of the pulse wave signal waveform (scale of absorbed light intensity) can be calculated more accurately by determining the amount of change in absorbed light intensity with respect to the change in pressure applied to the measurement site (pressure due to blood pressure or pressure due to external pressure). Can be converted into a blood pressure value scale, and as a result, not only the previously determined average blood pressure value but also the maximum blood pressure value and the minimum blood pressure value can be accurately derived.
[0032]
In addition, by applying a known pressure to the measurement site with a cuff, or by sinking the measurement site to a known depth (applying a known pressure), as shown in FIG. In the graph, a difference in change rate (slope) appears. FIG. 6 is a partial graph of the absorbed light intensity B (inclination: α _B ) and the absorbed light intensity A (inclination: α _A ) shown in FIG. is there.
[0033]
Here, since the amount of change in the slope of the absorbed light intensity due to the pressurization: Δα corresponds to the applied known pressurization value, the relationship between the slope of the absorbed light intensity and the pressure value can be derived. As a result, the slopes of absorbed light intensity: α _A and α _B shown in FIG. 6 can be converted into pressure values, and the instantaneous absolute blood pressure value corresponding to the minimum value of the absorbed light intensity in each case is obtained. be able to. Therefore, the absorbed light intensity on the vertical axis in the graph of absorbed light intensity can be converted into a pressure value, and as a result, not only the average blood pressure value obtained previously but also the maximum blood pressure value and the minimum blood pressure value are accurately derived. can do.
[0034]
Moreover, although the above-mentioned embodiment demonstrated the case where the light emission means 7 and the light-receiving means 8 of the pulse wave measurement means 3 were mounted | worn with a bather using the wristband 17, as illustrated in FIG. A configuration may be employed such as when it is provided in advance at a predetermined position on the wall surface, or when it is detachably provided on the inner wall surface of the bathtub. Accordingly, if the detachable light emitting means 7 and the light receiving means 8 are used, or if a plurality of the light emitting means 7 and the light receiving means 8 are embedded in the inner wall of the bathtub, the portion to be measured is submerged to a known depth and subjected to a plurality of pressures. It is also possible to measure the pulse wave at.
[0035]
In addition, the derived electrocardiogram waveform (or heart rate), pulse wave waveform, blood pressure value, etc. may be displayed on the display means 15 realized by a bathroom remote controller or the like so that the bather can check in real time. it can. Furthermore, if the signal processing means 14 determines that an abnormality is found in the measured electrocardiogram waveform (or heart rate) or blood pressure value, the alarm means 16 is used to send a voice message or the like to the bather. Can also be configured to call attention.
[0036]
In the above embodiment, the method of measuring the blood pressure value by the pulse oximetry method by wearing the wristband 17 on the wrist of the bather has been described. It is not limited to the wrist. For example, the wristband can be miniaturized and attached to the fingertip, and modification such as measuring the blood pressure of the fingertip can be performed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a bath sphygmomanometer.
FIG. 2 is a configuration diagram showing an example of pulse wave measuring means.
FIGS. 3A and 3B are graphs showing temporal changes in absorbed light intensity, and FIG. 3B is a graph showing an electrocardiogram waveform;
FIG. 4 is a graph showing the relationship between pulse wave propagation speed and mean blood pressure.
FIG. 5 is a graph showing a waveform of a pulse wave after application of pressure and a waveform of the pulse wave before application of pressure.
FIG. 6 is a graph showing the waveform of a pulse wave after applying pressure and the waveform of the pulse wave before applying pressure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bath sphygmomanometer 2 Heart rate measuring means 3 Pulse wave measuring means 4 Propagation time deriving means 5 Average blood pressure deriving means 6 Blood pressure deriving means 7 Light emitting means 8 Light receiving means 9 First calculating means 10 Electrode 11 Transmitting means 12 Amplifying means 13 Second calculation Means 14 Signal processing means 15 Display means 16 Alarm means 17 Wristband

Claims (3)

A bath sphygmomanometer that measures the blood pressure of a bather,
A heartbeat measuring means for measuring a heartbeat timing of the bather;
Pulse wave measuring means for measuring a pulse wave at a measurement site on the body surface of the bather;
A propagation time deriving means for comparing the pulse wave with the heartbeat timing and deriving the propagation time of the pulse wave from the heart to the measurement site;
Deriving the propagation velocity of the pulse wave from the propagation distance and the propagation time of the pulse wave from the heart to the measurement site, based on a predetermined first relationship between the pulse wave propagation velocity and the blood pressure value, Mean blood pressure deriving means for deriving an average blood pressure value at the measurement site;
The intermediate value of the pulse wave measured by the pulse wave measuring unit is specified as the average blood pressure value derived by the average blood pressure deriving unit, and the second relationship is a relationship between the pulse wave and the blood pressure value And blood pressure value deriving means for deriving the highest blood pressure value and the lowest blood pressure value at the measurement site from the pulse wave measured by the pulse wave measuring means based on the specified average blood pressure value. ,
A difference between the first pulse wave at the measurement site measured under atmospheric pressure and the second pulse wave at the measurement site measured under a second pressure different from the atmospheric pressure, the blood pressure value deriving means; And deriving the second relationship, which is a relationship between the pulse wave and the pressure, from the pressure difference between the atmospheric pressure and the second pressure, and converting the pulse wave into the blood pressure value. A bath sphygmomanometer, wherein the average blood pressure value, the maximum blood pressure value, and the minimum blood pressure value at a measurement site are derived. The pulse wave measuring means is based on a temporal change in received light intensity in the light receiving unit that irradiates light to the measurement site, a light receiving unit that receives the light scattered by the bather, and the light receiving unit. The bath sphygmomanometer according to claim 1, further comprising first calculation means for deriving the pulse wave. The heart rate measuring means includes a plurality of electrodes provided on the inner wall of the bathtub, a transmission means for transmitting each electric signal induced to the electrodes to the outside, an amplifying means for amplifying the electric signal, and the amplified The bath sphygmomanometer according to claim 1, further comprising: a second calculation unit that processes an electrical signal to derive the heartbeat timing.

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