DE102005029355A1 - Physiological measurements`, e.g. body temperature, monitoring arrangement, has sensors arranged so that transmission path between surface in body opening and respective sensor is approximately constant under prevailing operating conditions - Google Patents

Abstract

The arrangement has multiple sensors (2), which are surrounded by a housing that is applicable in a human body opening (10). The sensors are arranged in such a manner in the housing that a transmission path (w) between a body surface (10.3) in the opening and the respective sensor is approximately constant, under the prevailing operating conditions. The housing is formed by a hollow piece, and is made from elastic or partially transparent material e.g. silicon, thermoplastic elastomer and hydrogel.

Description

The The invention relates to an arrangement for monitoring at least one physiological measurand by means of a non-invasive measurement on a body surface comprising one or more Sensors coming from a housing surrounded in a body opening, especially in an ear canal can be used.

To For medical purposes, it is known in body orifices, for example in the ear canal Arrange sensors, on the basis of which physiological measures, eg. The body temperature, the oxygen saturation in the blood or the pulse rate, are detected and determined.

Such sensors, in particular optical sensors are for example from the document DE 39 10 749 A1 , the document US 6,283,915 B1 or document WO 2005/020806 A1.

adversely in the known sensors is that these contactless Measurement centered or free in the body opening, z. B. the ear canal arranged are. Due to the in shape and size interindividuell strongly varying Ear canal However, as a common features, the inclination of the eardrum and has two distinct bends, the housing of the sensor assembly is possible to the dimensions of the ear canal individually by means of so-called optoplastics, in which the sensors are integrated, adapt.

conditioned due to the required adaptability for different Ear sizes is a high wall thickness of the compliant and transparent housing material required. Leading to an undesirable direct optical coupling (also called optical cross talk) from the emitter of the optical sensor to its detector, as for example experimentally (see Ernst 2002 / - Diploma thesis at the FHS Jena "Development and evaluation of a micro-optical sensor system for non-invasive detection of cardiovascular parameters in the ear canal "or by the way called Monte Carlo simulation (see Gerbach 2003 / Diploma Thesis at the FHS Jena "modeling the beam paths and intensity distributions in emitter-receiver micro-assemblies for sensor applications) was detected. As a result of this cross talk will be dynamic range and resolution of the Sensors greatly reduced.

moreover it is from the hearing aid technology it is known that it is due to the strong interindividual size and Shape deviations of the human ear is not possible with those already known sensor arrangements due to the size of the sensors and the low Volume in the outer ear, especially in the ear canal a single sensor arrangement for all sizes of the human ear (also referred to as "one size fits all") to create and thus an acceptable compromise between sensor performance and to achieve the required wearing comfort.

In addition, it is known that the shape and the cross section of the ear canal or ear canal, in particular to the distal bow, in certain body movements, such as speaking, chewing, yawning or running, change by muscular actions. This results in a placement of the sensor in the ear canal to the known motion artifacts. Optical sensors according to the remission principle are particularly affected by the fact that due to the compliance and the movements of the ear canal wall according to the US 6,283,915 B1 the measuring signal changes. This is made especially difficult by the effect of the oscillating seismic mass of the sensor located inside the auditory canal with any body movements. The change in the effective optical path between the sensor and the body surface due to movements leads to measurement errors which are not taken into account in the prior art.

Of the The invention is therefore based on the object, a relation to the Prior art improved arrangement for monitoring at least one indicate physiological measurand.

The The object is achieved by the characteristics of the independent Claim 1. Advantageous embodiments of the invention are the subject the dependent claims.

The Invention is based on the consideration, that due to body movements changes caused in the body opening the measurement signal and resulting measurement errors largely avoided should be. The measurement errors due to body movements are particularly due an optical sensor to a change the transmission path, especially the optical transmission paths between sensor and body surface in the Body orifice, z. B. an ear canal wall. For this purpose, the sensor arrangement has one or more sensors, arranged in the housing are that the transmission path between the body surface in the Body opening and the approximate each sensor is constant. Here, the optical transmission path between sensor remains and body tissues even with a change in shape, for. B. by so-called motion artifacts of the ear canal approximately constant.

For this the sensor (s) preferably lie with a defined one Pressure, in particular with a pressure of 10 mmHg to 50 mmHg (at 1 mm of mercury = 133.322 Pa) to the body surface. In an arrangement of the sensor in the external auditory canal, for example, a optimal contact pressure of the sensor to the tissue of approx. 30 mmHg given.

In a possible embodiment this is the case made of a flexible or flexible, especially elastic and at least partially transparent material, in particular from Silicon or thermoplastic elastomer or a hydrogel formed. In this case, the housing has in the relaxed state dimensions that are at least equal or slight are bigger as the dimensions of the body opening, in which the arrangement can be used. This allows in the inserted state the sensor arrangement an optimum contact pressure of the housing and thus the sensor to the body surface. ever according to size of the dimensions of the housing, i.e. each slightly bigger the external dimensions of the housing across from the dimensions of the body opening, the bigger it is Contact pressure. Preferably, a contact pressure of about 10 mmHg set to 50 mmHg. It acts a radial pressure of the flexible housing outer wall on the inner wall of the body opening. Of the optimal contact pressure depends on of the tissue type in the respective body opening and the individual Constitution. At a too high contact pressure, the wearing comfort impaired become. Therefore, such a contact pressure is preferably set, that an optimal measurement result with sufficiently good wearing comfort allows is.

The flexible and self-adapting material of the housing also allows for insertion the sensor assembly, a mechanical cross-sectional reduction by the housing pressed together and into the body opening, z. B. the ear canal is introduced. Is the arrangement in the desired Position, so expands due to the compliance of the material the housing again off, leaving the housing wall on the body surface and the tissue with the desired Contact pressure applied. In this case, such a material is used, the a sufficiently good rigidity and a good compliance for safe and comfortable insertion, removal and carrying the arrangement having achieved the desired contact pressure. In addition allows an arrangement formed from such a flexible material an open Shaping and production in standard sizes with clothing size graduations for a universal Use of the arrangement with high quantities. Compared to the known from the prior art custom-made on basis The impression technique is a cost-effective production in large quantities allows.

In a further embodiment, the housing is formed from a hollow body. For example, the housing is open on both sides, in particular open along the longitudinal axis. This allows ventilation of the body opening and, when positioned in the ear canal, pressure equalization between the outer and inner ear and only a marginally limited hearing. Thus, the housing can be designed as a hollow cylinder. Depending on the shape of the body opening, the housing has an outer shape that corresponds to the shape of the body opening. For example, when using the arrangement in the ear canal, the housing has a frusto-conical shape or a two-part form. 4 on.

In a further embodiment shows the case a housing wall with a thin wall thickness of about 1 mm to about 3 mm. This allows a minimal weight the arrangement in favor of a good resistance to so-called Motion artifacts.

For a simplification of introduction and placing the assembly in the body opening is along the housing the longitudinal axis with at least one longitudinal section Mistake. The longitudinal slot allows by manual compression of the housing a reduction of the cross-section of the arrangement, making it easier be introduced into the body opening can. Especially in applications in time-critical emergency medicine is the rapid insertion of such a sensor arrangement for monitoring of physiological measures of Meaning and advantage.

Additionally or Alternatively, the housing can be at least comprise an at least partially radially encircling holding element. For example, the retaining element as an internal spring element or an outside lying circumferential lamella formed. It is also possible to the surface of the housing To arrange training, which serve to increase the liability. through of the spring element, for. B. a radially encircling spring, can during clamping the spring, the arrangement easily in the body opening or run. In the relaxed state of the spring is preferably a defined Contact pressure for the application of the sensor to the body surface in the body opening adjustable. The outside lying slats or means of increasing the adhesion may additionally or be provided as an alternative to the spring element and allow a secure hold of the assembly in the body opening.

In a preferred embodiment, the sensor or sensors are in the region of the outer wall of the housing. In particular, the sensor is arranged in an accessible from the inside cavity of the housing. For example, the sensor is clamped in this cavity, z. B. used in so-called snap-in technique, glued and / or cast or used by similar methods. This allows a cost-effective installation of the tested and prefabricated sensors and a simple, for example, accessible from the inside interchangeability. Since the cavity does not break through the surface of the housing, a simplified approval process is also possible when using the arrangement in the medical field.

ever according to the function and application of the arrangement, the housing is at least partially transparent, in particular in the region of the sensor (s) transparent. Thus, the arrangement can also be optical Sensors include.

Preferably is the case with a surface layer made of a biocompatible material. In particular, one is provided such pollution-resistant surface, for example in a use of the arrangement in the ear canal a material discoloration by Cerumen exposure prevented or at least reduced.

In a further embodiment is the case preferably multi-shelled. In this case, the housing has a inner and an outer shell on, wherein the inner shell of a resilient material, in particular made of silicone, a thermoplastic elastomer or a hydrogel is. The outer shell is preferably made of a biocompatible material, in particular a thin one Rubber or latex coating educated.

Depending on the specification and function of the sensor arrangement, an optical reflectance sensor, a temperature sensor, a pulse-frequency measuring sensor and / or an oximetry measuring sensor are provided as sensors. The integration of the sensors in the housing of the device allows a non-invasive measurement, ie a measurement without an intervention that would damage the body surface, for example the arterial oxygen saturation. As an optical reflectance sensor, for example, from the DE 103 09 747 A1 known Auflichtsensor used. The sensor allows due to the small dimensions of about 3 mm × 5 mm × 1.5 mm, the integration in arrangements for small body openings, such. B. the ear canal. In this case, the sensor is particularly suitable for integration in the shell of the housing or in the outer wall of the housing of the arrangement. As a temperature sensor, for example, a thermistor, a thermocouple or other suitable sensor is used.

For an improvement the measurement accuracy of the arrangement are preferably several similar Sensors along the circumference of the housing arranged distributed. As a result, the signal / noise ratio of Measurement improves and the artifact susceptibility of the device, for example significantly reduced by averaging the acquired measured values.

ever according to the function and position of the arrangement, the integrated in the housing Sensors over a cable guide with an external power supply and an external evaluation unit be connected. For this purpose, the cable guide is integrated into the housing. Preferably, the cable guide for one preferably free mobility of the user on a strain relief. This is the cable management for example, within the assembly as a straight cable and outside the arrangement as a spiral cable with an interposed Strain relief executed. Also, the data transfer can be wireless done, z. B. over a radio link or an inductive or capacitive coupling, be connected to the evaluation.

For as possible Accurate positioning of the assembly in the body opening is a on the housing Positioning mark or other suitable shape provided. For example, a colored mark, z. B. a radial circumferential color line, as end mark for the introduction the arrangement provided for this color line. Also, a type marker be applied to the housing to identify the arrangement.

The particular advantages of the invention are that the transmission paths, especially optical transmission paths between Sensor and tissue even with changes in shape the body surface, for example remain nearly constant due to motion artifacts. For this are the sensors in the outer shell or the outer skin of the housing in an open cavity from the inside used. In addition, the sensor is due to the flexible design of the housing made of an elastic material permanently with a defined pressure the body surface of the Body opening pressed.

embodiments The invention will be explained in more detail below with reference to a drawing.

In this demonstrate:

1 schematically in cross section an arrangement for monitoring a physiological measured variable by means of a sensor integrated in the housing,

2 schematically a possible embodiment of a arranged in a body opening arrangement according to 1 in longitudinal section, and

3 . 4 schematically further alternative embodiments for an arrangement according to 1 in longitudinal section.

each other corresponding parts are in all figures with the same reference numerals Mistake.

1 shows an arrangement in cross section 1 for monitoring at least one physiological measured variable, for. B. body temperature or oxygen saturation in the blood. This includes the arrangement 1 at least one sensor 2 in a housing 4 the arrangement 1 is integrated. The housing 4 is preferably made of a flexible and compliant material 4.1 , z. As silicone, thermoplastic elastomer or a hydrogel. Preferably, the housing 4 as a hollow body, e.g. B. a hollow cylinder or a hollow shell truncated cone formed. This allows the sensor 2 from the inside into a housing wall of the housing 4 be used.

For receiving the sensor 2 in the housing wall comprises the housing 4 a cavity 4.2 into which the sensor 2 can be used interchangeably. For example, the sensor 2 into the cavity 4.2 clamped. Also, the sensor can 2 for permanent positioning and fixation in the cavity 4.2 glued or poured.

For easy installation and removal of the arrangement 1 includes the housing 4 an at least partially radially encircling holding element 4.3 on. In the area of the cavity 4.2 is the holding element 4.3 with an undercut 4.3.1 provided so that the sensor 2 into the cavity 4.2 can be snapped or clamped. Alternatively, for fixing the sensor 2 in the cavity 4.2 an additional, not shown detent or clamping element may be provided.

The holding element 4.3 is like in the 1 shown formed as an internal spring element. By compressing the flexible and flexible housing 4 becomes the cross section of the arrangement 1 reduced so that it can be easily installed and removed. Additionally or alternatively, the housing 4 along the longitudinal axis extending longitudinal section 4.4 also showing the change in cross section of the assembly 1 used during installation or removal.

As a sensor 2 For example, a temperature sensor, an optical sensor, in particular a remission sensor, a pulse-frequency measuring sensor and / or an oximetry measuring sensor are used. The sensor 2 is via a cable guide 2.1 in a conventional and manner with a power supply 6 and an evaluation unit 8th connected, as in the 2 is shown. Also, the sensor can 2 wireless with the power supply 6 and / or the evaluation unit 8th in a conventional manner, e.g. B. via a radio link or a capacitive or inductive coupling connected.

The 2 shows the arrangement 1 in longitudinal section and in a body opening 10 inserted state. As a body opening 10 serves in the present application, an ear canal 10.1 an outer ear, the sound conduction from the auricle 10.2 ensures the eardrum, not shown. In this case, the sensor arrangement 1 in the outer part of the ear canal 10.1 used. The outer part of the ear canal 10.1 Closes immediately to the auricle 10.2 and indicates as body surface 10.3 An inner ear wall made of elastic cartilage, which is subject to changes in shape due to body movements.

In this embodiment, the sensor 2 into the cavity 4.2 for defined fixation and cable routing 2.1 in the case 4 arranged for strain relief of the connections. That is the flexible material of the housing 4 surrounds the sensor 2 and the cable management 2.1 , For an optical sensor, the housing 4 in the area 4.5 the cavity 4.2 transparent.

In the inserted state of the arrangement 1 in the body opening 10 , the ear canal 10.1 is the sensor 2 such in the case 4 used that the transmission path w between body surface 10.3 and the sensor 2 is approximately constant. For this purpose, the housing 4 in the relaxed state, dimensions slightly larger than the dimensions of the body opening 10 are. Thus, the sensor is located 2 with a defined pressure of 10 mmHg to 50 mmHg to the body surface 10.3 at. This in turn causes the movements of the body surface caused by body movements 10.3 and resulting changes in the transmission path w significantly reduced and prevented as possible. As a result, a particularly accurate measurement result in the monitoring of the physiological parameter, eg. As the oxygen saturation in the blood allows. In addition, the sensor 2 as close as possible to the body surface 10.3 in the case 4 integrated. The sensor is preferred 2 in the area of the outer wall of the housing 4 arranged.

For inserting the arrangement 1 in the ear canal 10.1 becomes the case 4 pressed together. The resulting reduction in the cross section of the arrangement 1 is supported by the longitudinal section 4.4 and the holding element designed as a spring element 4.3 , The holding element 4.3 can be both the fixation of the sensor 2 in the cavity 4.2 as well as the fixation of the arrangement 1 in the body opening 10 serve. Is the arrangement 1 in the ear canal 10.1 introduced, so the housing expands 4 off and the housing wall is located on the body surface 10.3 with a defined contact pressure, which is optionally adjustable on. Conversely, by repressing the out of the ear canal 10.1 outstanding housing head 4.6 the order 1 slightly out of the body opening 10 be led out. Alternatively, the arrangement 1 be built in the manner of a pacifier. By pulling the case 4 in the length in non-illustrated embodiment, the cross section of the arrangement 1 reduced in size, allowing an entry and exit in the body opening 10 is relieved. Also, in a further alternative embodiment of the housing 4 this may be formed of a material with so-called shape memory. For example, a hydrogel having a smaller cross-section at ambient temperature and expanding at a temperature in the range of body temperature of 37 ° C.

The execution of the housing 4 as a particular open on both sides hollow body allows venting and pressure equalization. In an arrangement designed as an auditory canal sensor 1 In addition, the hearing is only slightly limited and remains largely intact.

3 shows an alternative embodiment for an arrangement 1 , In addition to the inner holding element 4.3 can have one or more external fins 4.7 that the case 4 Radial rotate, be provided. The slats 4.7 serve in particular the fixation of the arrangement 1 in the body opening 10 ,

Instead of an optical sensor as a sensor 2 a temperature sensor may be provided so that no transparent area 4.5 in the case 4 is provided. Also, as shown by a dashed line, several, in particular similar sensors 2 along the circumference of the housing 4 be arranged distributed.

4 shows a further alternative embodiment of the arrangement 1 with a housing 4 that's in the body opening 10 to be introduced, front housing part 4.8 several flexible and flexible bristles 4.8 for fixing the arrangement 1 in the body opening 10 includes. The order 1 has a pacifier shape and is in the manner described above by pulling the housing 4 in the length in the body opening 10 can be inserted and released.

The housing 4 has a transparent area in the form of a transparent window 4.5 for an integrated behind the wall in the optical sensor 2 on.

In a further possible embodiment, the housing 4 be constructed multi-shelled. For example, an inner shell 4.a from an outer shell 4.b surround. The inner shell 4.a serves to accommodate the sensor 2 and is the defined concern of the sensor 2 with a predetermined approximately constant distance on the body surface 10.3 formed of a flexible and resilient material. The outer shell 4.b , in particular a particularly thin-walled shell serves the biocompatibility of the arrangement 1 and is designed as a latex or rubber coating.

For accurate positioning of the assembly 1 in the body opening 10 or for identification in the housing 4 integrated sensors 2 can the case 4 with a marker 12 , z. B. in the manner of a line marking for position marking or type designation to be provided.

An example is the arrangement 1 in the present case for use in an auditory canal 10.1 described. Therefore, the housing formed of a flexible and partially transparent material 4 Also referred to as transparent and flexible earmold. The earmold is an insert made individually for the respective ear and made of plastic material, which may for example comprise a hearing device or other electronic components. By the execution of the housing 4 made of flexible and flexible material, the sensor arrangement according to the invention 1 be used for different ear sizes. This means that an individual and complex individual production for each ear can be omitted. Rather, the arrangement 1 be made in different standard sizes and shapes in the style of clothing sizes.

When using the arrangement 1 in another body opening 10 , z. B. in the nostril, has the arrangement 1 one with the appropriate body opening 10 corresponding form. Also, the arrangement 1 one or more sensors as required 2 , in particular similar and / or different types of sensors.

1

arrangement for monitoring physiological measurands

2

sensor

2.1

cable management

4

casing

4.1

flexible material

4.2

cavity

4.3

retaining element

4.3.1

undercut

4.4

longitudinal section

4.5

transparent window

4.6

housing head

4.7

lamella

4.8

front housing part

4.9

bristles

4.a

inner Bowl

4.b

outer shell

6

power supply

8th

evaluation

10

body cavity

10.1

ear canal

10.2

auricle

10.3

body surface

12

mark

w

transmission path

Claims (18)

Arrangement ( 1 ) for monitoring at least one physiological measurand by means of a noninvasive measurement on a body surface ( 10.3 ) comprising one or more sensors ( 2 ), by a housing ( 4 ), which are in a body opening ( 10 ), characterized in that the sensor or sensors ( 2 ) in the housing ( 4 ) are arranged such that the transmission path (w) between the body surface ( 10.3 ) in the body opening ( 10 ) and the respective sensor ( 2 ) is approximately constant under the given conditions of use. Arrangement according to claim 1, characterized in that the sensor or sensors ( 2 ) at a defined pressure, in particular at a pressure of 10 mmHg to 50 mmHg at the body surface ( 10.3 ) and this pressure is generated by the elastic properties of the housing and / or by suitable means which cause a mechanical Vorspannug Arrangement according to claim 1 or 2, characterized in that the housing ( 4 ) of a resilient, in particular elastic and at least partially transparent material ( 4.1 ), in particular made of silicone or thermoplastic elastomer or a hydrogel whose dimensions in the relaxed state are at least equal to or slightly larger than the dimensions of the body opening ( 10 ). Arrangement according to one of claims 1 to 3, characterized in that the housing ( 4 ) is formed from a hollow body. Arrangement according to one of claims 1 to 4, characterized in that the housing ( 4 ) has a housing wall with a thin wall thickness of about 1 mm to about 3 mm. Arrangement according to one of claims 1 to 5, characterized in that the housing ( 4 ) along the longitudinal axis at least one completely or partially continuous longitudinal section ( 4.4 ) having. Arrangement according to one of claims 1 to 6, characterized in that the housing ( 4 ) at least one at least partially radially encircling holding element ( 4.3 ). Arrangement according to claim 7, characterized in that the holding element ( 4.3 ) as an embedded in the housing wall or on the inner side of the housing attached spring element or an outer circumferential lamella ( 4.7 ) is formed or has external or means for increasing the adhesion. Arrangement according to one of claims 1 to 8, characterized in that the sensor or sensors ( 2 ) in the region of the outer wall of the housing ( 4 ) are arranged. Arrangement according to one of claims 1 to 9, characterized in that the sensor or sensors ( 2 ) in an internally accessible cavity ( 4.2 ) of the housing ( 4 ) are arranged, in particular in these stapled, glued, poured. Arrangement according to one of claims 1 to 10, characterized in that the housing ( 4 ) at least in the region of the sensor or sensors ( 2 ) is transparent. Arrangement according to one of claims 1 to 11, characterized in that the housing ( 4 ) with a surface layer ( 4.b ) is made of a biocompatible material. Arrangement according to one of claims 1 to 12, characterized in that the housing ( 4 ) is constructed mehrschalig. Arrangement according to one of claims 1 to 13, characterized in that the housing ( 4 ) an inner shell ( 4.a ) and an outer shell ( 4.b ), wherein the inner shell ( 4.a ) of a resilient material and the outer shell ( 4.b ) are formed from a biocompatible material, in particular from a thin and transparent rubber or latex coating. Arrangement according to one of claims 1 to 14, characterized in that as a sensor ( 2 ) An optical remission sensor and / or a temperature sensor are provided. Arrangement according to one of claims 1 to 15, characterized in that a plurality of sensors ( 2 ) are arranged distributed along the housing periphery. Arrangement according to one of claims 1 to 16, characterized in that in the housing ( 4 ) a cable guide ( 2.1 ), which causes an effective decoupling of mechanically acting forces between cable and sensor Arrangement according to one of claims 1 to 17, characterized in that on the housing ( 4 ) a position marker ( 12 ) or another suitable shape for positioning in the body opening is provided.