WO2000053080A1

WO2000053080A1 - A device for enhancement and quality improvement of blood-related signals for use in a system for non-invasive measurements of blood-related signals

Info

Publication number: WO2000053080A1
Application number: PCT/IL1999/000621
Authority: WO
Inventors: Alexander Finarov; Ilya Fine
Original assignee: Orsense Ltd.
Priority date: 1999-03-09
Filing date: 1999-11-18
Publication date: 2000-09-14
Also published as: IL129790A0; US6731963B2; AU1176400A; US20020077535A1

Abstract

A disposable device is presented aimed at enhancing blood-related signals and improving their quality during non-invasive measurements of these signals. The device is applicable to a patient's extreme organ, and comprises a thin elastic cover for wrapping at least a part of the extreme organ in a manner to provide under systolic pressure on the tissue within the wrapped part of the organ. This enables to provide even pressurization of the organ tissue, which results in the enhancing of the blood-related signal. At least a portion of the cover is made of a material enabling the non-invasive measurements of the blood-related signal therethrough.

Description

A Device for Enhancement and Quality Improvement of Blood-Related Signals for Use in a System for Non-Invasive Measurements of

Blood-Related Signals

FIELD OF THE INVENTION

The present invention is in the field of non-invasive measurements of physiological parameters of patients, and relates to a device for the enhancement and quality improvement of blood-related signals.

BACKGROUND OF THE INVENTION

Non-invasive methods for measuring various blood-related parameters have become very popular due to the fact that these measurements, in distinction to invasive ones, have no such undesirable requirement as physical withdraw of a blood sample from the patient's body. Non-invasive measurements are based on the pulsatile nature of arterial blood, and utilize optical monitoring techniques capable of detecting such pulsatile blood behavior. Results obtained from pulse measurements can be used for determining various physiological parameters such as blood oxygen saturation, hematocrit, the concentration of hemoglobin, glucose, carbon dioxide, arterial blood pressure, etc. The optical monitoring techniques of the kind specified typically utilize the detection of light transmitted or reflected from different locations on the patient's body. According to some of these techniques, disclosed for example in U.S. Patent Nos. 5,101,825, changes in the blood parameters at a specific location are measured as a function of changes in the blood volume at this location. Other techniques, disclosed for example in U.S. Patent No. 5,499,627, utilize impedance measurements.

Various methods aimed at increasing the natural pulsatile signal of a patient for effecting non-invasive optical measurements have been developed. These methods are disclosed for example in the following patent documents: DE 19629342, US 5,638,816, WO 9843096 and in Israel Patent Application No. 124965 which is a co-pending application assigned to the assignee of the present application.

According to the above methods, the natural pulse signals are either detected and used for measurements, or created by performing various suitable procedures which are typically based on the use of a probe applied to the patient's finger (pulse oximetry) or other extremities. These methods typically require well-established, stable and reproducible capillary, venous and arterial blood presence at the location under measurement. As known, to meet such a requirement, slight homogeneous pressure may be applied to the soft tissue in the vicinity of the measurement location. Unfortunately, such a pressure-inducing holder is usually a part of the measurement probe itself, i.e. it is associated with a specific sensor used in a specific measurement system.

Generally, a pressure-inducing element can be applied to the patient's finger prior to the measurement itself, so as to create the required preconditions for starting blood-related measurements. To this end, it is desirable to have a pressure-inducing holder that would be applicable for any patient's finger, irrespective of a patient's individual peculiarities.

Some of the conventional measuring devices utilize folded adhesive sensors, namely disposable adhesive sensors with optics embedded therein. Other devices utilize non-disposable sensors, which are typically in the form of a clip to be placed on the patient's finger and fixed by a spring. Elastic cushions support the optical elements and prevent slipping of the sensors off the finger.

However, the existing disposable devices fail to provide homogeneous pressure applied to the finger. As a result, even pressurization of the finger tissue cannot be achieved. Furthermore, none of the existing devices can be used solely for the enhancement and quality improvement of blood-related signals, regardless of the measurement technique used for measuring these signals. For example, adhesive sensors are applicable to the pulse-oximetry technique based on the detection of optical signals, while being unsuitable for the impedance-based or the like technique.

SUMMARY OF THE INVENTION

There is accordingly a need in the art to improve conventional techniques for measuring blood-related signals by providing a novel disposable and quickly mountable/removable device for applying to the patient's extremity so as to enhance blood-related signal and improve its quality.

It is a major feature of the present invention to provide such a device, which can be used with a sensor of any suitable known kind capable of detecting the blood-related signal to measure any suitable parameter that can be derived therefrom.

It is a further feature of the present invention to provide such a device that can be applied to various extreme organs of various patients.

There is thus provided according to the invention, a disposable removable device for applying to a patient's extreme organ, the device comprising: a thin cover for wrapping at least a part of the extreme organ in a manner to provide under-systolic pressure on the tissue within said at least part of the organ, thereby providing even pressurization of the organ tissue which thus results in the enhancement and quality improvement of blood-related signal, at least a portion of the cover being made of a material enabling non-invasive measurements of the blood-related signal therethrough.

Preferably, the device is applied to the patient's finger. The cover is elastic and may itself be such as to press the finger tissue whilst wrapping the finger. Alternatively, or additionally, the device may comprise a pneumatic device or a mechanical device, e.g., a pressing ring to be placed on the organ (e.g., finger) above the cover. By operating such a device, e.g., by twisting the ring, the desired pressure can be established.

The elasticity of the cover and its small thickness provides a slight regular pressurization on the tissue, which is always less than the systolic blood pressure. This results in the enhancement of the pulsatile and non-pulsatile blood-related signals, prevents blood flow disturbance during measurement, and stabilizes the finger tissue during measurements, thereby improving the quality of the measured signals.. Preferably, the device also provides a heating effect to heat the organ up to desired temperature (about 38°C), thereby enhancing the blood-related signal even more. The heating ability of the device increases the accuracy of the non-invasively derived blood-related parameters such as blood oxygen saturation, blood pressure, hemoglobin, glucose, cholesterol and other analyte concentrations. The shrinkage effect by heating the cover affects tissue pressurization.

According to another aspect of the present invention, there is provided a disposable device for use with a measurement system capable of non-invasive measurements of blood-related signals, wherein the device is applicable to a patient's extreme organ and comprises a thin elastic cover for wrapping at least a part of the extreme organ in a manner to provide under systolic pressure on the tissue within said at least part of the organ, thereby providing even pressurization of the organ tissue which results in the enhancement of blood-related signal and improvement of its quality, at least a portion of the cover being made of a material enabling non-invasive measurements of the blood-related signal therethrough. According to yet another aspect of the present invention, there is provided a system for non-invasive measurements of blood-related signals, the system comprising a measurement unit and a disposable device for applying to a patient's extreme organ, wherein said disposable device comprises a thin elastic cover for wrapping at least a part of the extreme organ in a manner to provide under systolic pressure on the tissue within said at least part of the organ, thereby providing even pressurization of the organ tissue which results in the enhancement of blood-related signal and improvement of its quality, at least a portion of the cover being made of a material enabling non-invasive measurements of the blood-related signal therethrough.

According to yet another aspect of the present invention, there is provided a method for obtaining enhanced and quality improved blood-related signals within at least a part of a patient's extreme organ utilizing a thin cover for applying to said at least part of the organ, the method comprising the steps of: (a) providing said cover wrapping said at least part of the organ, at least a portion of the cover being made of a materials enabling non-invasive measurements of the blood-related signal therethrough; and (b) applying even pressurization to said at least part of the organ so as to provide under systolic pressure within a tissue of said at least part of the organ.

According to yet another aspect of the present invention, there is provided a method for non-invasive measurements of at least one blood-related parameter within at least a part of a patient's extreme organ, utilizing a device for enhancement and quality improvement of blood-related signals, the method comprising the steps of:

- providing a thin cover wrapping said at least part of the organ, at least a portion of the cover being made of a materials enabling non-invasive measurements of the blood-related signal therethrough; - applying pressure to said at least part of the organ so as to provide even pressurization of a tissue of said at least part of the organ resulting in under systolic pressure within said tissue, thereby enhancing a blood-related signal;

- applying sensor means to said at least part of the organ, the sensor means being capable of detecting said enhanced blood-related signals and generating data representative thereof;

- deriving from said data said at least one blood-related parameter.

The sensor means may utilize an illumination assembly for illuminating at least the part of the organ with incident radiation, e.g., near infra-red (IR) radiation of 600-2000nm wavelength, and a detection assembly for detecting response of the illuminated part. The location of the detection assembly depends on the kind of response that is to be detected, i.e., reflected or transmitted signal.

It is understood that to enable the application of such a radiation-based sensor means, the cover should be formed with means enabling light propagation therethrough. To this end, the entire cover may be transparent with respect to the incident radiation (e.g., near IR radiation). In this case, the cover should be of a sufficient thickness (i.e., preferably not exceeding 50μm), so as to prevent the collection by the detection assembly of incident radiation rounding the wrapped organ, instead of signal response of the organ. Alternatively, when a thicker cover is used (e.g., of 0.5mm in thickness), the cover may be formed with at least one optical window transparent for near IR radiation, thereby enabling the application of the sensor means to a portion of the wrapped part of the organ below the window. If the transmitted signal is to be detected, two optical windows should be provided made at opposite sides of the cover. Should the reflected signal be detected by the sensor means, the provision of only one optical window is sufficient for measurements, but two spaced-apart optical windows located at the same side of the cover can be used. The non-transparent regions of the cover absorb light waves going around the cover' material thickness and through the skin of the wrapped organ, and prevent these waves from being collected by the detection assembly. This increases the signal-to-noise ratio of the detected signal.

The non-transparent regions can be manufactured from the same material as that of the transparent regions, but with additional pigments such as carbon, titanium oxide, BaS, BaS0₄, etc. that make these regions non-transparent for near

IR radiation. Materials suitable for the manufacture of the cover are silicon, latex and other flexible, elastic and transparent for near IR radiation materials.

BRIEF DESCRIPTION OF THE DRA INGS

In order to understand the invention and to see how it may be carried out in practice, a preferred embodiment will now be described, by way of non- limiting example only, with reference to the accompanying drawings, in which:

Figs, la and lb illustrate a device, constructed according to one embodiment of the invention, which is, respectively, in an inoperative position, prior to being applied to a patient's finger, and in an operative position being applied to the patient' s finger;

Fig. 2a illustrates a device in an inoperative position thereof constructed according to another embodiment of the invention;

Figs. 2b and 2c illustrate two operational steps for applying the device of Fig. 2a to the patient's finger; Fig. 3a illustrates a device in an inoperative position thereof constructed according to yet another embodiment of the invention,;

Figs. 3b and 3c illustrate two operational steps for applying the device of Fig. 3a to the patient's finger;

Figs. 4a to 4c illustrate one more embodiment of the present invention; Figs. 5a to 5c graphically illustrate the main operational principles of the device of either of Figs, la-lb, 2a-2c, 3a-3c or 4a-4c, when being used with, respectively, optical-, impedance- and occlusion-based measurements; and

Fig. 6a to 6c schematically illustrate three more embodiments of a device according to the invention, DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the preferred embodiments of the invention, the patient's finger constitutes an extreme organ to which a device for enhancing blood-related signals is applied. Referring to Figs, la and lb, there is illustrated a device 2 associated with the patient's finger P and capable of enhancing blood-related signals within the finger. The device 2 comprises a cover 4, which is rolled up into a spherical-like segment when in an inoperative position of the device 2, i.e. prior to being applied to the finger P (Fig. la). To put the device 2 in operation, the cover 4 is unrolled so as to wrap the patient's finger P (Fig. lb). To this end, the cover 4 is made of an elastic thin material, for example rubber, silicone, PVC, polyurethane, polyethylene, so as to be easily shifted from its normally inoperative, folded position into the operative, extracted position.

The elastic cover slightly presses the tissue of the finger P. As indicated above, the elasticity of the cover and its small thickness provides slight, regular pressurization on the tissue, for example within a range 5-20 mm Hg, which is always less than the systolic blood pressure. This slight pressurization of the tissue, on the one hand, causes the enhancement and quality improvement of the pulsatile and non-pulsatile blood-related signals within the wrapped portion of the finger P, and, on the other hand, prevents blood flow disturbance during future measurements.

The cover 4 is made from such materials that do not affect any particular technique for measuring blood-related parameters. More specifically, for optical, acoustic and impedance-based measuring techniques, the material of the cover should allow for the penetration of, respectively, light, sound or electrical current into the tissue. For example, rubber, silicone, latex, PVC, nylon, paraffin, etc. can be used in the manufacture of the elastic cover.

It should also be noted, although not specifically shown, that the pressuring elastic film-like cover may be formed by disposing quick drying glues such as Poly Vinil Alcohol, some resin solutions or the like, onto the finger. These materials, while drying, form a thin film coating on the finger.

As further shown in Fig. lb, the device 2 also comprises a heating element 6 located above the extracted cover 4 wrapping the finger P. In this specific example, the heating element 6 is a conductive material connectable to a power source (not shown) that supplies sufficient voltage, for example in a range 1-6 V.

There are several constructional possibilities for implementing a heating effect in the device 2. The heating element 6 may be a separate constructional part to be applied to the finger P at a separate operational step, upon unrolling the cover 4 to wrap the finger. The heating element may be made of conductive silicone, conductive clothes, metal wire like NiCr, etc. The heating element may be attached to the cover, for example by making the heating element from sufficiently flexible material to allow for rolling/unrolling thereof together with the cover. Heating elements may be implanted into the cover. The material resistance of the cover itself, or the chemical exothermic reaction of two or more components (e.g., polyurethane) applied to the cover, may be utilized.

Thus, the pressuring film-like cover 4 provides the enhancement and quality improvement of the blood-related signals, while the heating element 6 enhances these signals even more, and increases the accuracy of blood-related parameters that are derived from the measured signals.

It should, however, be noted that the provision of any heating element is optional. As indicated above, on the one hand, the provision of the heating effect increases the accuracy of the non-invasively derived blood-related parameters, and, on the other hand, the shrinkage effect by heating the cover effects the tissue pressurization. These blood-related parameters are such as blood oxygen saturation, blood pressure, hemoglobin, glucose, cholesterol and other analytes concentration, etc.

Reference is now made to Fig. 2a illustrating a device 20 to be applied to the patient's finger P for enhancement and quality improvement of blood-related signals within the fmger. To facilitate understanding, the same reference numbers are used for identifying those components which are identical in the devices 2 and 20. The device 20 comprises a cover 4, a heating element 6, and a flexible strap 8 (constituting a pressing assembly) capable of forming a ring on the finger above the cover, so as to attach the cover to the finger. The cover 4 is in the form of a thin flat film, which is shaped like a circle when in an inoperative position of the device 20. The heating element 6 is designed like a pair of spirals extending along two opposite regions of an outer surface of the film 4. The strap 8 may be made of a flexible wire, or may be a stretchable material, for example the same as that of the film. Figs. 2b and 2c more specifically illustrate the main operational steps for applying the device 20 to the patient's finger P to put the device in operation. The film cover 4 is stretched, thereby wrapping the finger P and extending the heating element 6 along the wrapped portion of the finger.

When the cover 4 wraps the patient's finger P, the opposite ends of the strap 8 are fastened so as to form a ring 8 on the finger above the cover. If the strap 8 is made of a flexible wire, its ends can be twisted together to fix the ring's diameter, thereby applying desired pressure to the finger tissue (Fig. 2d). Should the stretchable material be used for the strap 8, Velcro-like fasteners or the like would be appropriately provided at the ends of the strap. Obviously, any other suitable technique may be used for providing a ring-like support element 8 on the finger in a manner allowing for varying the ring's diameter.

Figs. 3a-3c illustrate a device 30 for enhancement and quality improvement of blood-related signals within the finger P. The device 30 is generally similar to the devices 2 and 20, but has a somewhat different design. In the device 30, the cover 4, which is made of a high elastic material, is provided with a supporting ring 38 having a preset stretching force. The ring 38 may be made of a plastic material. To stretch the cover for attaching the device 30 to the patient's finger, the ring 38 is inserted onto the finger, and force is applied to the ring 38 for moving it along the fmger. When the cover 4 is stretched up to a preset maximum value, it forces against the ring 38. When the force applied to the ring 38 exceeds the preset stretching force thereof, the ring 38 tears off and can be removed from the finger. Hence, the desirably stretched cover 4 wraps the finger P whilst applying the desired even pressurization thereto.

Figs. 4a illustrates a device 40 constructed according to yet another embodiment of the invention. Similarly, the same reference numbers are used for identifying those components, which are identical in the device 40 and in the previously described examples. Here, in distinction to the device 30, a cover 4 is made of a relatively low elastic material, and its periphery region is attached to a supporting twisting ring 48. A separate ring 48' made of a suitable material such that the ring 48' is hardly movable along the finger P as compared to the ring 48. The ring 48' may be formed with a slot, rather then being a closed loop, so as to adjust the diameter of the ring 48' and to facilitate its mounting on the finger, after attaching the cover 4.

Thus, to put the device 40 in operation, the ring 48 is inserted onto the finger P, thereby stretching the cover 4. To sufficiently stretch the cover 4 so as to apply the desired pressure to the tissue, the ring 48 is twisted, in a clockwise direction in Fig. 4c, while the ring 48 serves as a locking element preventing the movement of the ring 48 whilst being twisted.

Turning now to Figs. 5a-5c, there are graphically illustrated the main operational principles of either of the above-described device when being used for, respectively, optical-, impedance- and occlusion-based measurements. Each of these figures illustrates two graphs, Gi and G₂, corresponding to the time dependence of the measured blood-related signal R, respectively, before and after the application of the device. These graphs present experimental results obtained whilst performing the respective measurements using known measurement systems. In the optical and occlusion measurements, what actually is measured is the intensity of light transmitted through the patient's finger, R being the light intensity. As for the impedance-based technique, R corresponds arbitrary units of impedance. As clearly seen in the figures, the application of the device according to the invention enhances the blood-related signal approximately by 2-3 times. More specifically, ΔR_a are 5% and 10% of the total transmission signal before and after the application of the device, respectively; ΔRb are 3% and 6% of the total impedance signal before and after the application of the device, respectively; ΔR⁽¹⁾ _C and ΔR⁽²⁾ _C are, respectively, 5% and 20%, and 10% and 40% of the total transmission signal.

The main principles of the optical- and impedance-based measurements do not form a part of the present invention and are known per se, and therefore need not be specifically described. As for the occlusion-based technique, it also does not form a part of the present invention, and is the subject matter of the above-indicated Israel Patent Application No. 124965, which is a co-pending application, assigned to the assignee of the present application. This application is therefore incorporated herein by reference with respect to this specific example of one possible measurement technique for which the device according to the present invention is suitable. The main principles underlying the occlusion-based technique utilize the fact that light absorption characteristics of a blood perfuse medium dramatically changes when the character of the blood flow changes. In distinction to the conventional measuring techniques of the kind specified, e.g., pulse-oximetry, occlusion-based measuring technique deals with non-volumetric blood-related signals. It should be noted that such a cup-like cover 4 should be provided with means enabling optical measurements therethrough, based on the detection of either reflected or transmitted light response of the blood perfuse medium. In other words, the cover should be constructed so as to enable the light waves propagation therethrough. If the cover is substantially thin, i.e., practically not exceeding 50μm, it can be entirely transparent for predetermined incident radiation, e.g. near IR radiation (600-2000nm), being made of silicon, latex, etc.

Figs. 6a-6c illustrate three different examples, respectively, of a cup-like cover to be used in the disposable device according to the invention. In these examples, the cover may be thicker than 50μm, for example being of 0.5mm in thickness. Although the cover is illustrated here in its ready to be mounted on a patient's finger position, it should be understood that this position may be achieved by unrolling the cover.

According to the example of Fig. 6a, the cover 4 is formed with its upper and lower portion 50a and 50b made of a material transparent to near IR radiation (e.g., silicon or latex), and two opposite side portions 52a and 52b made of a material non-transparent (absorbing) to near IR radiation. This, for example, may be achieved by manufacturing the entire cover from the same transparent material and forming its side portions 52a and 52b with additional pigments such as carbon, titanium oxide, BaS, BaS0₄, etc. The provision of the opposite transparent portion 50a and 50b enables the use of such cover 4 with a transmission-based measurement unit. In other words, illumination and detection assemblies of the measurement unit should be associated with the portions 50a and 50b, respectively, or vice versa.

In the example of Fig. 6b, the cover 4 is formed with two opposite optical windows 54a and 54b. The windows are made of a material transparent for near IR radiation, while all the other regions 55 of the cover, except for those occupied by the windows, are made of a material non-transparent for near IR radiation. This design of the cover is also suitable for use with a transmission-based measurement unit. In the example of Fig. 6c, the cover 4 is formed with a single optical window 56. This design is suitable to be used with a reflection-based measurement unit. As shown in the figure, for the purposes of the reflection-based measurement technique, an additional optical window 56' may be provided being located close to the window 56 at the same side of the cover. The windows 56 and 56' are spaced by a small non-transparent region.

Those skilled in the art will readily appreciate that various modifications and changes may be applied to the above-described embodiments of the invention without departing from its scope defined in and by the appended claims.

Claims

CLAIMS:

1. A disposable device for applying to a patient's extreme organ, the device comprising a thin elastic cover for wrapping at least a part of the extreme organ in a manner to provide under systolic pressure on the tissue within said at least part of the organ, thereby providing even pressurization of the organ tissue which results in the enhancement and quality improvement of blood-related signal, at least a portion of the cover being made of a material enabling non-invasive measurements of the blood-related signal therethrough.

2. The device according to Claim 1, wherein said cover is in the form of an elastic film rolled to form a spherically-shaped segment when in an inoperative position of the device, and being unrolled to wrap the patient's organ when putting the device in operation.

3. The device according to Claim 1, wherein said cover is in the form of a flat thin film when in an inoperative position of the device, said film being stretchable so as to wrap the patient's organ when putting the device in operation.

4. The device according to any one of Claims 2 or 3, and also comprising a pressing assembly for attaching to the patient's organ above the cover.

5. The device according to Claim 4, wherein said pressing element, when in the operative position of the device, is in the form of a strap extending along at least a part of a periphery region of the cover, so as to form a ring when in the operative position of the device, thereby enabling adjustment of the ring diameter to apply a desired pressure.

6. The device according to Claim 5, wherein said strap is made of flexible wire, twisting of the straps' ends when in the operative position of the device enabling said adjustment of the ring's diameter.

7. The device according to Claim 4, wherein said pressing assembly is in the form of a ring extending along a periphery region of the cover, the ring having a preset stretching force, such that when a force applied to the ring exceeds said preset stretching force the ring tears off.

8. The device according to Claim 4, wherein said pressing assembly comprises two rings, one ring being attached to a periphery region of the cover and being capable of being twisted thereby stretching the cover, when in the operative position of the device, the other ring serving as a locking mechanism, preventing movement of said one ring along the extreme organ whilst being twisted.

9. The device according to Claim 1, wherein the cover is in the form of a thin film formed by disposing a specific glue material onto the organ and quickly drying the glue.

10. The device according to Claim 1, and also comprising a heating assembly for heating said tissue.

11. The device according to Claim 10, wherein said heating assembly comprises a heating element formed by a conductive material associated with a voltage supply source.

12. The device according to Claim 11 , wherein - said cover is in the form of an elastic film rolled into a spherically-shaped segment when in an inoperative position of the device, and being unrolled to wrap the patient's organ when putting the device in operation;

- said heating element is made of flexible material capable of being rolled and unrolled together with the cover when shifting the device between its inoperative and operative positions.

13. The device according to Claim 11, wherein

- said cover is in the form of a flat thin film when in an inoperative position of the device, said film being stretchable so as to wrap the patient's organ when putting the device in operation; - said heating element extends along two opposite periphery regions of an outer surface of said film, thereby extending along said at least part of the patient's organ when in the operative position of the device.

14. The device according to Claim 1, wherein the thin cover is made of elastic material providing a slight regular pressurization on said tissue, said pressurization being less than diastolic blood pressure.

15. The device according to Claim 1, wherein the entire cover is made of said material enabling radiation waves propagation therethrough.

16. The device according to Claim 15, wherein said material is such as to enable propagation of sound waves into the tissue.

₅ 17. The device according to Claim 15, wherein said material is such as to enable electrical current to be induced in the tissue.

18. The device according to Claim 15, wherein at least a portion of the cover located within a measurement area has a thickness substantially not exceeding

50μm. ₁₀ 19. The device according to Claim 1, wherein said material is rubber.

20. The device according to Claim 1, wherein said material is silicone.

21. The device according to Claim 1, wherein said material is latex.

22. The device according to Claim 1, wherein said material is PVC.

23. The device according to Claim 1, wherein said material is nylon. ₁₅

24. The device according to Claim 1, wherein said material is paraffin.

25. The device according to Claim 1, wherein said material is polyethylene.

26. The device according to Claim 1, wherein said at least one portion of the cover is made of the material substantially transparent with respect to predetermined radiation waves, and is surrounded by a material of the cover

₂0 substantially non-transparent with respect to said radiation waves.

27. The device according to Claim 1, wherein the cover is formed with two portions made of said material substantially transparent with respect to predetermined radiation waves, said two portions being surrounded by a material of the cover substantially non-transparent with respect to said radiation waves.

25 28. The device according to Claim 27, wherein said two portions are located opposite to each other at opposite sides of the cover.

29. The device according to Claims 26 or 27, wherein the surrounding material is composed of said material substantially transparent for the radiation waves and is composed of predetermined pigments providing the non-transparency of the

₃₀ surrounding material.

30. The device according to Claim 29, wherein said predetermined pigments include at least one from the following list: carbon, titanium oxide, BaS and BaS0₄.

31. The device according to Claim 1, wherein said extreme organ of the ₅ patient's body is his finger.

32. The device according to Claim 1, wherein said blood-related signal is natural pulsatile component of arterial blood.

33. The device according to Claim 1, wherein said blood-related signal is volumetric.

₁₀ 34. The device according to Claim 1, wherein said blood-related signal is non-volumetric.

35. A disposable device for use with a measurement system capable of non-invasive measurements of blood-related signals, wherein the device is applicable to a patient's extreme organ and comprises a thin elastic cover for

₁5 wrapping at least a part of the extreme organ in a manner to provide under systolic pressure on the tissue within said at least part of the organ, thereby providing even pressurization of the organ tissue which results in the enhancement and quality improvement of blood-related signal, at least a portion of the cover being made of a material enabling non-invasive measurements of the blood-related signal

20 therethrough.

36. A system for non-invasive measurements of blood-related signals, the system comprising a measurement unit and a disposable device for applying to a patient's extreme organ, wherein said disposable device comprises a thin elastic cover for wrapping at least a part of the extreme organ in a manner to provide

25 under systolic pressure on the tissue within said at least part of the organ, thereby providing even pressurization of the organ tissue which results in the enhancement and quality improvement of blood-related signal, at least a portion of the cover being made of a material enabling non-invasive measurements of the blood-related signal therethrough.

37. A method for obtaining enhanced and quality improved blood-related signal within at least a part of a patient's extreme organ utilizing a thin cover for applying to said at least part of the organ, the method comprising the steps of:

(c) providing said cover wrapping said at least part of the organ, at least a ₅ portion of the cover being made of a material enabling non-invasive measurement of the blood-related signal therethrough; and

(d) applying even pressurization to said at least part of the organ so as to provide under systolic pressure within tissue of said at least part of the organ.

₁0 38. A method for non- invasive measurements of at least one blood-related parameter within at least a part of a patient's extreme organ utilizing a device for enhancing of blood-related signals and improving their quality, the method comprising the steps of:

- providing a thin cover wrapping said at least part of the organ, at least a portion ₁5 of the cover being made of a material enabling said non-invasive measurements therethrough;

- applying pressure to said at least part of the organ so as to provide even pressurization of a tissue of said at least part of the organ resulting in under systolic pressure within said tissue, thereby enhancing a blood-related signal;

20 - applying sensor means to said at least part of the organ, the sensor means being capable of detecting said enhanced blood-related signals and generating data representative thereof;

- deriving from said data said at least one blood-related parameter.