DE102007020247A1 - Compression measurement, at a compression stocking and the like, has a textile carrier for a fluid cell with a membrane and containing a pressure sensor linked to an evaluation/memory unit - Google Patents

Abstract

The system to measure the compression force applied e.g. by a medical stocking has a sensor between the stocking and the skin. The sensor has a textile carrier (1) with a fluid cell (2) and a membrane (3) distorting under pressure. A pressure sensor (4) is within the cell. The carrier has a conductor oath (5) for connection to an external evaluation and memory unit (6) with a Wheatstone Bridge (9).

Description

The The invention relates to a device for measuring a contact pressure a medical compression means, in particular a compression stocking or association according to the preamble of claim 1.

medical Compression means are beneficial for the support of venous Blood flow and lymphatic motion in the extremities, in particular in the area of the legs, used. An application is also known Such compression means in the field of sports. It will mainly used on compression textiles, for example pulled over as a stocking or as a bandage around the extremity be wrapped.

A accurate determination of the case on the corresponding body part exerted Compression pressure is mainly in the medical field of great Importance to the therapeutic effect of the compression means accurately track and plan. An assessment of the applied pressure can indeed from the therapeutic Be derived from success, but this is far enough for medical purposes not from.

So is it for the attending physician for the treatment planning particularly important, by the compression means exerted To know the exact pressure or to be able to estimate exactly before. Doctors and Therapists working as part of their training with such compression means be made familiar for the Create such means of objective training and control. Besides that is an objective assessment of therapeutic success and efficacy the compression means used to third parties, in particular health insurance or similar control bodies. And finally serves an objective measurement of the compression pressure also of quality assurance and further development of the compression means used. A accurate measurement of the pressure exerted by the compression means pressure therefore mandatory.

Currently existing measuring systems are used to measure the compression pressure mainly due to capacitive, resistive or piezoresistive sensors. These be directly on the skin of the body part hung up and then covered with the compression agent. They measure the compression pressure on the spot. In many However, such sensor systems have the problem that the sensors not or only insufficient adapted to the flexible body surface can be. The Sensors are not or only insufficiently form-fitting, this leads to to impairments of Measurement accuracy and in many cases to incorrect measurements.

To counteract this problem, one resorts to either very small and rigid or large flexible sensors. In the WO 2006/103048 A1 For example, a flexible force distribution sensor with multiple layers on a capacitive basis is described. The EP 1211633 A1 describes another capacitive textile-like sensor. However, such sensors are very sensitive to changes in the surface geometry by the underlying capacitor assembly and have, especially under the influence of bends on strong accuracy and sensitivity fluctuations.

Furthermore, piezoresistive measuring systems are known. For example, in the journal Biomedical Engineering 41 (1996) 3, p. 69-73 a piezoresistive pressure measuring system that is marketed under the name MCDM-1 and was developed specifically for determining a compression pressure under dressings.

The DE 39 33 827 A1 describes a method for recording an external pressure applied to a tissue. Among other things, the pressure sensor used there consists of a so-called electro-thermal-mechanical film (ETM film). Such a system is intended to specifically detect the compression effect caused by compression stockings. The system described there is also intended to allow a measurement of the pressure distribution on the body surface by means of a defined arrangement of the sensors. In such and similar systems, a direct on-site measurement takes place. In most cases, however, only a single measuring point or a measuring point can be detected accurately.

The DE 195 05 765 C2 describes a measuring system in which by means of a fluid, the measured pressure is transmitted to a located outside the compression bandage pressure sensor. In this case, the sensor body is designed as a pillow-like means, wherein the cushion is inserted between the compression means and the body part and is connected via a hose system with the external pressure sensor. Such a system must be individually fixed to the body part. This makes the process very complex. In addition, the measured results determined by the individual attachment of the measuring system are essentially not reproducible.

Finally, the document describes DE 103 14 211 A1 a pressure measuring system in which pressure-sensitive yarns are integrated into a textile garment, for example a stocking, thereby detecting the pressure of the compression means. One however, such system is limited to pressure detection in the foot area of diabetics.

It Therefore, the object is a device for measuring a contact pressure indicate a medical compression means, with the on a simple and reproducible way the pressure of the compression medium can be determined. The device is designed in a very simple way on the body part to be fix and it should be about it In addition, a measurement of the pressure distribution can be made from which general Data about derive the effectiveness of the medical compression agent. The device should also reliable Allow pressure measurements under changing geometric conditions in particular, bends of the sensor arrangement by movements of the body part to no falsifying influences lead to the measured pressure values.

The object is achieved with a device for measuring a contact pressure of a medical compression means, in particular a compression stocking or -verbandes, comprising a insertable between the body surface and the compression means sensor body with a sensor point, which is characterized by the following features in claim 1 inventive features:
According to the invention, the sensor body consists of a textile carrier. The sensor point is designed as a fluid cell fastened to the textile carrier and sealed off. The fluid cell has a pressure deformable membrane and a pressure sensor disposed within the cell. Between the membrane and the pressure sensor, a fluid is stored. The textile carrier has a contacting track between the pressure sensor and an external evaluation and storage unit.

Of the Accordingly, sensor body according to the invention contains Sensor points resulting from the deformation of a membrane and one of it resulting pressure change perform a pressure measurement in a fluid. These sensor points exist from single, outward closed cells whose membranes are direct or indirect on the body surface or rest on the compression means and deformed by the pressure of the compression means become. Inside the cells, the fluid takes on a pressure, the external pressure of the compression means at the location of the fluid cell corresponds. The internal pressure the fluid cell that adjusts itself becomes the location of the fluid cell The inside of the pressure sensor converts it into a measuring signal, which is transmitted via the Contacting track in the textile carrier to the evaluation and storage unit derived and converted into a pressure reading.

Appropriate or advantageous embodiments are in the subclaims called.

One particular advantage of such a measuring arrangement is that in principle it does not matter in which position the individual Sensor point to lie on the body surface comes. The membrane deformation propagates inside the fluid as a uniform increase in pressure out. Each sensor point that is in contact with the body surface, and which is deformed by the compression means, therefore provides from the outset a geometry value unadulterated by a geometry.

Conveniently, is a temperature sensor in the immediate vicinity of the fluid cell and / or within the fluid cell having incorporated into the textile carrier Contacting track for the Temperature sensor for evaluation and storage unit arranged.

Of the Temperature sensor is used for a continuous temperature measurement on Location of the fluid cell for determining a temperature value, with the the temperature influence is corrected for the pressure in the fluid cell can be.

Of the Pressure sensor within the fluid cell is expediently used as a semiconductor sensor with a pressure change variable Resistance trained. Such sensors can be miniaturized and are sufficiently accurate.

It is a resistance measuring device for measuring the electrical Resistance of the pressure sensor provided. This is expediently as a wheatstone bridge educated. A wheatstone bridge are for precise Resistance measurements are the tool of choice.

Of the textile carrier is in an advantageous embodiment as one on a body part portable, body part shape posing garment, in particular a stocking, formed. It forms a totality of fluid cells and Kontaktierungsbahnen a the body part enclosing, one location-dependent Pressure distribution on the surface of the body part measuring sensor network.

In order to is a simple application of the sensor body possible by the textile carrier and with him the fluid cells is worn like a garment and so one defined position on the surface of the body part occupies.

In an advantageous embodiment, the device is one of an elastic knitted fabric, woven or knitted fabric with net-like incorporated Fluidzel len with pressure sensors and the knitted fabric or knitted fabric passing Kontaktie existing garment in connection with a computer system with means for data processing and visualization.

Thereby forms the garment and its sensor network in conjunction with the computer system and Visualization is a means of easy recording and presentation one the entire surface of the body part comprehensive pressure distribution.

Of the sensor body is in an advantageous embodiment dimensionally stable to the contour of the underlying underground, d. H. of the body part, customizable. The sensor body points to one in the sensor body embedded flexible and shape-stabilizing material surface. This is flexible and can be molded to the body part, so that the sensor body after completion of fitting or after completion of the pressure measurement remains in the set form.

The shape-stabilizing material surface consists in an expedient embodiment from a three-dimensional spacer knitted fabric.

A method for operating a device according to the features mentioned is characterized by the following method steps:
First, a precise position applying the textile support, in particular the garment, with the sensor network of the entirety of the fluid cells on the body part, then the contacting tracks are connected to the external evaluation and storage unit. Subsequently, the medical compression means, in particular the compression stocking or bandage is applied. The pressure of the compression means causes a deformation of the membrane of each fluid cell and a registration of a fluid pressure at the pressure sensor of the fluid cell.

Of the Pressure value at the pressure sensor is determined by the evaluation and storage unit read. There is a processing of the measured pressure value through the evaluation and storage unit.

Conveniently, takes place by a location adjacent to the fluid cells arrangement of Temperature sensors simultaneously running temperature measurement. there Within the evaluation and storage unit, the measured values are measured Pressure values depending on corrected by the measured temperature value.

It takes place in an advantageous extension of the method one over the Body part surface spatially resolved pressure measurement by means of a network-like entirety of fluid cells and pressure sensors. This takes place in the evaluation and Storage unit a spatially resolved Preparation of measured pressures, in particular a measured value visualization.

The device and the method will now be explained in more detail by means of exemplary embodiments. To clarify serve the 1a to 3 , The same reference numbers are used for identical or identically acting parts.

It shows:

1a a schematic arrangement of a textile carrier with a fluid cell, contacting tracks and an evaluation and storage unit,

1b an exemplary fluid cell in a sectional view,

2a an arrangement of fluid cells, a temperature sensor and contacting tracks in an elastic knitted fabric,

2 B an arrangement of fluid cells, a temperature sensor and contacting tracks in an elastic knitted fabric,

3 a hosiery-shaped textile support having a network of fluid cells and temperature sensors.

1a and 1b show a schematic structure of the device according to the invention. A textile carrier 1 For example, a knitted fabric, woven or knitted fabric containing a fluid cell 2 , These. has a membrane deforming under an external pressure 3 on. Inside the fluid cell is a pressure sensor 4 , This registers the pressure change caused by the deformation of the membrane in the fluid. For voltage supply or for deriving the measuring pulses at the pressure sensor are contacting tracks 5 intended. These are to contacts 5a with the fluid cell, in particular with the pressure sensor connected. The fluid contained in the fluid cell 7 is completely separated from the external environment by the fluid cell.

The fluid cell can be connected to the textile carrier both inseparably and inseparably. In a releasable embodiment, the contacting webs are expediently incorporated firmly in the textile carrier, while the fluid cells are placed in contact, in particular adhesively bonded to the webs, fastened by means of a pushbutton or attached to a Velcro connection. This eliminates a complicated wiring. The fluid cells form self-contained, attachable and modular units. These can be stored easily. The textile carrier can be considered a normal one Garment treated, in particular easily cleaned or disinfected.

Conveniently, the fluid contained in the fluid cell consists of a gas, in particular of air. Destruction of the fluid cell thereby does not lead to any contamination or functional impairment of the contacting tracks. In principle, however, any fluid can be used which converts the membrane deformation into a uniform pressure change within the fluid cell. The fluid 7 may therefore be a liquid. If possible, this should lead to no contamination or functional impairment in the case of destruction of the fluid cell and should evaporate without residue. Under the action of body heat easily evaporating, not or only poorly electrically conductive liquids, such as ethanol, prove to be particularly suitable for such purposes.

The Size of the fluid cells depends on the degree of miniaturization of the pressure sensors contained in them, the required spatial resolution the pressure measurement and the accuracy of the pressure measurement. typically, are fluid cells in the range of a few millimeters to one Size of a few Centimeters in diameter appropriate.

By a circuit integrated in the fluid cells is possible a preliminary evaluation of the measured data.

For further evaluation and storage or for operation of the pressure sensor is an external evaluation and storage unit 6 intended. This contains in addition to a voltage supply for the pressure sensors means 6a for data preparation, storage and visualization, such as a storage medium, a program for data acquisition and processing, a monitor and the like components more. The evaluation and storage unit as a whole can be designed as a personal computer with the corresponding hardware and software components. However, portable, miniaturized embodiments which store measured values and output measured values measured at specific time intervals to an external unit for data processing are particularly advantageous.

Furthermore contains the evaluation and storage unit 6 Components for the operation of the pressure sensor 4 , This includes, in particular in the case of a resistive, semiconductor-based pressure sensor, a precision measuring circuit for determining the electrical resistance of the pressure sensor. Appropriately, this is a Wheatstone bridge circuit 9 intended. This may expediently be integrated directly in the fluid cell.

Farther can Addressing circuits integrated into the evaluation and storage unit, with which pressure sensors of different fluid cells in an external Switch Wheatstone bridge or by the integrated Wheatstone bridges in Read out the resistance values determined for the fluid cells, so that the electrical resistances a series of pressure sensors and thus determine location-dependent pressure values let, as in the following closer accomplished becomes.

The 2a and 2 B show exemplary embodiments of the textile support with fixedly integrated fluid cells in section. The textile carrier 1 consists in the embodiment in 2a from a knitwear 12 made completely or partially from elastic fibers 13 is made. In the knitted fabric are the fluid cells 2 integrated. Immediately adjacent to the fluid cells are temperature sensors 8th of which one is shown in the figure. The elastic knitted fabric is intended to ensure that the carrier with the fluid cells comes to rest tightly and non-slip on the corresponding body part. Furthermore, the contacting tracks 5 arranged in knitted fabric.

Of the Pressure of the knitted fabric, which at rest, d. H. without applied medical compression means, is applied to the fluid cells, leads to a Measurement offset on the pressure sensors, in a very simple way can be expected out. The pressure of the compression means leads to a over the Measurement offset increasing pressure value in each fluid cell. The difference between this pressure value and the measurement offset is then considered the actual Measured value for registered the pressure of the compression agent. Therefore, the Fluid cells in this example completely integrated into the knitted fabric be and do not protrude from the body of the textile carrier out. Due to the low height The fluid cells also have the possibility of applying a textile, for. B. a tissue.

In the embodiment of 2 B is a knitted fabric carrier 14 with incorporated elastic knitted threads 15 intended. The knitted fabric can in particular be designed as an elastic spacer knitted fabric which has a relatively small thickness. The fluid cells 2 are embedded in this embodiment in the knitted fabric that their membranes 3 at least partially protrude from the knitted fabric and rest directly on the body part or the compression means.

Also in this embodiment are temperature sensors 8th arranged in the vicinity of the fluid cells or in the fluid cells themselves. The knitted fabric is also with the contacting tracks 5 Mistake.

Due to the tight elastic structure of the textile carrier, ie the knitted or knitted fabric, a design of the sensor body in the form of a piece of clothing is possible. 3 shows a measuring stocking consisting of a knitted or knitted fabric 10 with a series of fluidly distributed over the sock tissue fluid cells 2 and temperature sensors 8th , The contacting tracks 5 traverses in this embodiment, the entire stocking from the foot over the heel and ankle to the calf, connect the fluid cells and temperature sensors and open into an interface 16 , which is designed as a standardized connector for an external computer.

Of the sensor body or the membrane of the fluid cell is not in one here a figure illustrated embodiment designed so that its shape on the measuring surface, so the Contours of the body part concerned, can be adapted and form-fitting on the ground, z. B. one leg. This is especially true for larger sensor bodies in size ranges of a few centimeters advantageous.

In the sensor body is in a further embodiment incorporated a material for shape stabilization. Conveniently, For this purpose, a three-dimensional spacer knitted fabric is used, which is flat and at least partially arranged in the sensor body.

A Use of the shape-stabilizing material, especially in the membrane the fluid cells is then appropriate or required if the sensor body pressed relatively strong together by the attached pressure medium becomes. The shape-stabilizing material prevents a superimposition the inside of the membrane and a flattening of the fluid cell at a gaseous Filling.

Of the Pressure sensor can in this embodiment, but also in others embodiments mentioned here also outside if required the actual sensor body are located and over one or more coupling pieces with the sensor body and the fluid cell (s).

The in 3 shown measuring stocking is pulled like a normal garment over the foot and lower leg. In principle, thigh-length or pantyhose-like embodiments are also possible. The external interface 16 is with a corresponding counterpart to the evaluation and storage unit 6 connected. The evaluation and storage unit now addresses all fluid cells within the sock, in particular their pressure sensors, and all temperature sensors. This is done in particular by querying the state of the individual contacting tracks by the evaluation and storage unit. Since the location of each individual contacting track is known and can be unambiguously attributed to a specific area on the body part due to the fit of the measurement sock, the resistance measured values of the individual pressure sensors can be unambiguously assigned to a measuring location.

Subsequently, the pressure sensors are successively in the Wheatstone bridge circuit 9 switched and determines their resistance offset. This is done by switching the individual contacting tracks into the Wheatstone bridge. This offset value may be associated with a pressure offset acting as a quiescent pressure within the fluid cell below a given temperature and without an applied compression means.

at integrated in the fluid cells Wheatstone bridges is the resistance offset or the static pressure immediately available from any pressure sensor.

In in the same way, the temperature sensors of the stocking are addressed and the temperature at each of the sensor points is determined. The one by the Fluid cells determined static pressure and the associated temperature value is stored in the evaluation and storage unit.

Subsequently, will the compression means applied by a compression stocking, a dressing or the like means pulled over the measuring stocking or is wound. The membranes of the fluid cells are characterized deformed, wherein the pressure of the fluid increases in the fluid cells while changing the resistance in the individual pressure sensors.

The Evaluation and storage unit now switches all as described Pressure sensors of the fluid cells individually in the Wheatstone bridge circuit, registered whose changed electrical resistance and calculates a pressure value. at Wheatstone bridges integrated into the fluid cells are used at the pressure sensors measured resistance or pressure value individually read.

In parallel, a temperature value is determined at the temperature sensors and used to correct the pressure values determined by the fluid cells. The temperature correction of the measured pressure is in the simplest case carried out by using the equation of state of the idea len gas of the pressure measured by the pressure sensor within the fluid in each fluid cell to a pressure at a suitably selected standard temperature is converted. This can be assumed to be an isochoric state change. With this assumption, the volume of the fluid must be in each fluid cell is not necessarily known.

A Refinement of the temperature correction of the measured pressure is in principle thereby possible by having the temperature sensor integrated with in the fluid cell and is arranged in the interior thereof. Furthermore, more accurate Equations of state for the fluid for correction of the pressure, for example the equation of state according to van der Waals.

At the in 3 In the embodiment shown, the position of each fluid cell within the stocking and on the body part is basically known through the fit of the stocking and does not change as a result of the tight fit of the measurement stocking and of the compression means. When separable from the textile carrier fluid cells according to the preceding embodiments, the measuring stocking is first covered with the first unoccupied contacting paths. Thereafter, the fluid cells are placed on the measuring stocking at precisely defined and suitably pre-marked measuring points. The evaluation and storage unit addresses these measuring points or the pressure sensors of the attached fluid cells as described via the contacting tracks.

The individual pressure sensors within the fluid cells is therefore a Clearly a well-defined place can be assigned. The evaluation and storage unit therefore about Visualization and display means, with which the pressure distribution over all fluid cells and pressure sensors spatially resolved can be represented. The individual, through the pressure sensors determined pressure values are thereby in an internal array or a other appropriate variables or data structure written and stand for the generation of a virtual model of the body part ready, that the pressure distribution generated by the compression means shows.

In the embodiment 3 Accordingly, the virtual model of a lower leg is generated with foot and displayed properly on a display that shows the pressure distribution of the applied compression means by different color codings and makes certain inhomogeneities of the pressure spatially resolved visible.

A Such measurement can be completed by the pressure distribution in the measuring stocking over recorded and stored time-resolved over a defined period of time becomes. For this, the measurements of each individual pressure and temperature sensor triggered by an internal clock in the evaluation and storage unit and the results of each measurement time assigned. The measuring stocking can with such time-resolved measurements up to several days to be monitored body part remain.

The The device and the method are not as described here embodiments limited. In the context of expert Acting can amendments on the embodiments take place, which do not leave the scope of the inventive concept. Further embodiments emerge in particular from the dependent claims.

1

textile carrier

2

fluid cell

3

membrane

4

pressure sensor

5

Kontaktierungsbahn

5a

contact

6

evaluation and storage unit

6a

Data preparation, Storage, visualization

7

fluid

8th

temperature sensor

9

operating components for pressure sensor, in particular Wheatstone Bridge

10

measuring Trumpf

12

knitted fabrics

13

elastic fiber

14

Knitted

15

elastic Gewirkefaden

16

interface

Claims (11)

Device for measuring a contact pressure of a medical compression means, in particular a compression stocking or bandage, comprising a sensor body insertable between body surface and compression means with at least one sensor point, characterized in that the sensor body consists of a textile support ( 1 ) and the sensor point as a attached to the textile carrier and completed fluid cell ( 2 ) with a pressure-deforming membrane ( 3 ) and a pressure sensor disposed inside the cell ( 4 ) is formed with a fluid stored between the membrane and the pressure sensor, wherein the textile carrier has a contacting track ( 5 ) for a connection of the pressure sensor with an external evaluation and storage unit ( 6 ) having. Device according to claim 1, characterized in that a temperature sensor ( 8th ) in the immediate vicinity of the fluid cell ( 2 ) and / or within the fluid cell with one in the textile carrier ( 1 ) incorporated contacting track ( 5 ) for the temperature sensor and the external evaluation and storage unit ( 6 ) is arranged. Device according to one of claims 1 or 2, characterized in that the pressure sensor ( 4 ) is formed as a semiconductor sensor having a variable pressure resistor. Device according to one of claims 1 to 3, characterized in that a resistance measuring device ( 9 ) is provided in the manner of a Wheatstone bridge for the pressure sensor. Device according to one of claims 1 to 4, characterized in that the textile carrier ( 1 ) as a piece of clothing which can be worn on a body part and which is in the form of a body part, in particular a measurement stocking ( 10 ), wherein a total of fluid cells ( 2 ) and contacting tracks ( 5 ) is formed as a body surrounding the sensor, a location-dependent pressure distribution on the surface of the body part measuring sensor network. Apparatus according to claim 1 to 5, characterized by a made of an elastic knitted fabric, woven or knitted fabric ( 12 . 14 ) comprising garment-like arranged fluid cells and the knitted fabric or knitted contacting webs clothing in conjunction with a computer system with means for data processing and visualization. Apparatus according to claim 1 to 5, characterized through one into the sensor body or the membrane of the fluid cell embedded flexible and shape-stabilizing Material surface. Device according to claim 7, characterized in that that the shape-stabilizing material surface is a three-dimensional spacer knitted fabric is. Method for operating a device according to claim 1 to 8, characterized by the method steps: - precise positioning of the textile carrier ( 1 ), in particular the garment with the sensor network of the fluid cells ( 2 ) on the body part, - connecting the contacting tracks ( 5 ) with the external evaluation and storage unit ( 6 ), - applying the medical compression means, in particular the compression stocking or dressing, - deformation of the membrane ( 3 ) of each fluid cell by the pressure action of the compression means and registering a fluid pressure at the pressure sensor ( 4 ) of the fluid cell, - readout of the pressure value at the pressure sensor by the evaluation and storage unit ( 6 ), - processing of the measured pressure value by the evaluation and storage unit. A method according to claim 9, characterized in that by an adjacent to the fluid cells ( 2 ) location of temperature sensors ( 8th ) a simultaneous temperature measurement is carried out, wherein within the evaluation and memory unit ( 6 ) the measured pressure values are corrected as a function of the respectively measured temperature value. Method according to one of claims 9 or 10, characterized in that a spatially resolved over the body part surface pressure measurement by means of a network-like totality of fluid cells ( 2 ) and pressure sensors ( 4 ), wherein in the evaluation and storage unit, a spatially resolved processing of the measured pressures, in particular a measured value visualization, takes place.