WO2001093755A1 - Monitor for non-invasive measurement of blood analytes - Google Patents

Monitor for non-invasive measurement of blood analytes Download PDF

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Publication number
WO2001093755A1
WO2001093755A1 PCT/GB2001/002516 GB0102516W WO0193755A1 WO 2001093755 A1 WO2001093755 A1 WO 2001093755A1 GB 0102516 W GB0102516 W GB 0102516W WO 0193755 A1 WO0193755 A1 WO 0193755A1
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characterised
device
nm
device according
blood
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PCT/GB2001/002516
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French (fr)
Inventor
Dawood Parker
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Whitland Research Limited
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Priority to GB0013964A priority patent/GB0013964D0/en
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Publication of WO2001093755A1 publication Critical patent/WO2001093755A1/en

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    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/145Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/145Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/14532Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue for measuring glucose, e.g. by tissue impedance measurement

Abstract

There is described a device for the non-invasive measurement of one or more analytes in blood in a patient's body part which comprises a light transmitter and a light detector characterised in that the transmitter and the detector are adapted to operate at wavelengths of from 700 to 1200 nm. There is also described a method of measuring blood analytes.

Description

MONITOR FOR NON-INVASIVE MEASUREMENT OF BLOOD ANALYTES

This invention relates to a novel monitor, particularly a monitor for the non-invasive measurement of blood analytes such as glucose in e.g. diabetics.

Diabetes mellitus (abbreviated to diabetes) is the name for a group of chronic or lifelong diseases that affect the way the body uses food to make energy necessary for life. Primarily, diabetes is a disruption of carbohydrate (sugar and starch) metabolism and also affects fats and proteins. In people who have diabetes the glucose levels vary considerably being as high as 40 mmol/1 and as low as 2 mmol/1. Blood glucose levels in people without diabetes vary very little, staying between 3 and 7 mmol/1. These levels follow the typical patterns shown in Figure la.

A non-invasive measurement device is known from US Patent No 5,553,613. US '613 describes a technique which uses the pulsatile component of the light intensity transmitted through the finger, from which to derive the glucose concentration non- invasively. It does this by using the wavelengths 805nm, 925nm, 970nm and the range 1000-1 lOOnm. The measurements were made by transmission, ie light was passed through the finger. However, as mentioned above, US '613 specifically relies upon the pulsatile component of the light transmitted through the patient. Such a pulsatile technique has clear disadvantages in that the pulsatile component of the light signal, whether transmitted or reflected, is less than 2% of the total signal.

Thus, prior art devices which use only the pulsatile component are much less sensitive and much more vulnerable to patient movement which can cause interference which is in the order of a few hundred times the relevant signal.

Moreover, the pulsatile signal identifies arterial blood specifically. Whilst this is advantageous when considering the pulmonary circulation of a patient, it provides no information on the patient's systemic circulation which is important for glucose determination. Further, pulsatile techniques are limited to use on body extremities, e.g. finger, ear lobe or the ball of the foot in babies or neo-nates. A non-invasive blood analyte monitor is also described in International Patent Application No WO 00/01294, Parker, et al. The Parker instrument is designed to measure one or more analytes in a patient's blood and comprises a light transmitter comprising a plurality of transmitting fibres positioned to transmit light and a light detector comprising a plurality of detector fibres. The device especially utilises the non-pulsatile element of a patient's blood.

In general terms the device scans the visible spectrum (500 to 600 nm) and near infra red spectrum (700 to 1100 nm). The visible spectrum is used for Hbl and SO2 determination, whilst the NIR is for blood glucose determination. Thus, in practice the device scans the spectrum from 500 to 1100 nm and therefore the device requires two spectrometers since, inter alia, there are no commercially available miniature spectrometers which can cover this wide range and which has the desired resolution in the visible spectrum.

When scanning the visible spectrum, oxygenated haemoglobin generally gives a characteristic "double hump" in the 500 to 600 nm region. This "double hump" enables the measurement of the haemoglobin index (Hbl) and/or the oxygen saturation (SO2) of blood, as described in WO '294.

However, we have now surprisingly found that the principal sub-harmonic of the "double hump" can be detected in the range 1000 nm to 1200 nm.

Thus, by the use of a sub-harmonic filter, the glucose and HbI/SO2 data may be determined by the spectrometer sequentially but with the advantage that only a single spectrometer is required which operates in a 700 to 1200 nm band width.

Thus according to the invention we provide a device for the non-invasive measurement of one or more analytes in blood in a patient's body part which comprises a light transmitter and a light detector characterised in that the transmitter and the detector are adapted to operate at wavelengths of from 700 to 1200 nm. Thus the device provided particularly includes a near infra red spectrometer and not a visible region spectrometer.

We further provide a device as hereinbefore described which also comprises a sub- harmonic filter. In particular the sub-harmonic filter is adapted to be switchable from a first position in which sub-harmonics are blocked to a second position in which sub-harmonics are permitted to transmit to the light detector.

Although various analytes may be measured, the detector of the invention is especially useful in measuring blood glucose levels. We especially provide a device for the non-invasive measurement of one or more analytes in blood in a patient's body part as herein before described which is adapted to measure blood glucose levels. Thus, when the sub-harmonic filter is in the first position, the spectrometer is capable of measuring blood glucose levels. The preferred wavelengths for measuring blood glucose are from 800 nm to 1100 nm.

The device may be capable of measuring other parameters either separately or in addition to blood glucose. An especially advantageous feature is the device may be adapted to measure blood oxygen saturation (SO2). Thus, when the sub-harmonic filter is in the second position, the NIR principal sub-harmonic is detected and Hbl and/or SO are measured.

As a further preferred embodiment we provide a device which is adapted to determine the haemoglobin index (Hbl) and/or oxygen saturation (SO2) of a patient's blood in the NIR. We especially provide a device as hereinbefore described which is adapted to determine blood glucose levels, Hbl and SO of a patient's blood by scanning light of wavelength from 700 to 1200 nm.

The device may be adapted for use, with any body part although it is preferable that it can be a finger or thumb. It is also an important feature of the present invention that for the determination of SO at least one or more of the wavelengths used are isobestic wavelengths. For the sake of clarity, by the teπn isobestic wavelength we mean a wavelength at which oxygenated haemoglobin and deoxygenated haemoglobin absorb the same amount of light. In a preferred embodiment substantially most of the wavelengths used are isobestic wavelengths.

Therefore, it is a further feature of the invention to provide a detector as hereinbefore described which also measures haemoglobin index (Hbl) and/or oxygen saturation (SO2) of blood. Although the aforementioned isobestic wavelengths are preferred, in order to, ter alia, calculate SO2, it is necessary to scan all of the wavelengths of the principal sub-harmonic, between 1000 and 1200 nm. Thus in a preferred device of the invention, the transmitter and the detector are adapted to operate at wavelengths of from 1000 to 1200 nm.

An especially preferred device operates at all of the wavelengths between 1000 and 1200 nm and at the aforementioned isobestic wavelengths. For such measurement, specific wavelengths are used, namely 1048 nm, 1124 nm and 1172 nm.

The detector may be positioned to deflect reflected light or transmitted light or any combination of these.

According to a further feature of the invention we provide a method of determining levels of blood analytes which comprises placing a non-invasive measuring device as hereinbefore described against a body part of a patient and using the detector to measure the light transmitted through or reflected from the body part characterised in that the transmitter/detector operates at a wavelength of from 700 to 1200 nm.

A particular feature of the method of the invention is that the method avoids the necessity of scanning the visible spectrum. The method of the invention is especially suitable for measuring blood glucose levels. We also provide a method of measuring Hbl and/or SO2 and optionally other parameters, which comprises placing a device of the invention against a body part of a patient and using the detector to measure the light transmitted through or reflected from the body part.

We especially provide a method of measuring Hbl and/or SO2 which comprises the use of a transmitter and a detector which operate in the near infra red. In a preferred embodiment the method of the invention comprises the use of a device operating at a wavelength of from 1000 to 1200 nm.

In a preferred embodiment of the invention, the method comprises determination of SO at the isobestic sub-harmonic wavelengths of 1048 nm, 1172 nm and a further wavelength of 1224 nm.

In a yet further feature of the invention we provide a device according to as herein before described programmed so as to calculate one or more of the haemoglobin index, the oxygen index and the blood oxygen saturation. Clearly, since blood oxygen saturation is dependent upon both the haemoglobin index and the oxygen index, the computer is programmed so as to calculate these equations first if blood oxygen saturation is to be calculated.

We also provide a computer programme product comprising a computer readable medium having thereon computer programme code means, when said programme is loaded, to make the computer execute a procedure to calculate one or more of the haemoglobin index, the oxygen index and the "whole blood" oxygen saturation as herein before described.

We also provide a computer programme product comprising a computer readable medium having thereon computer programme code means, when said programme is loaded, to make the computer respond to an audible command and execute a procedure to calculate one or more of the haemoglobin index, the oxygen index and the "whole blood" oxygen saturation as herein before described and to provide an audible display of the result.

Hbl, SO , Hb02, etc may be calculated using the formulae and/or algorithms described in the prior art and, particularly WO 00/01294.

The invention will now be illustrated by way of example only.

Example 1

Investigation of Principle Sub-Harmonic of Visible Spectra in NIR

Spectra were taken on the finger of patients in alternating succession using VIS (Visible), and NIR (Near Infra-Red) spectrometers. It is not possible with the present equipment to take simultaneous spectra. The spectra were taken in a normal rest state oxygenation, and with a cuff, causing the SO to drop over time.

The resulting spectra were analysed for their SO2 data, the NIR being transposed by dividing the wave table by two.

The sum of squares values indicated that the spectra were not free of non-linear scattering, and this therefore means that the SO2 values are only indicative of a trend. It further means that this is only true for values that are not near 100 or 0 %.

A cuff was applied to the upper arm and arterial blood supply constricted. Spectra were taken at intervals after the application of the cuff.

The results show a clear sequence of decreasing SO2's which are illustrated in Table I overleaf: Table I

Figure imgf000008_0001

The SO2a values are more sensitive to noise than SO2LSQ.

It is therefore possible to measure SO2 from the PSH (Principle Sub-Harmonic).

Claims

1. A device for the non-invasive measurement of one or more analytes in blood in a patient's body part which comprises a light transmitter and a light detector characterised in that the transmitter and the detector are adapted to operate at wavelengths of from 700 to 1200 nm.
2. A device according to Claim 1 characterised in that the device also comprises a sub-harmonic filter.
3. A device according to Claim 2 characterised in that the sub-harmonic filter is adapted to be switchable from a first position in which sub-harmonics are blocked to a second position in which sub-harmonics are permitted to transmit to the light detector.
4. A device according to Claim 1 characterised in that the device is adapted to measure blood glucose levels.
5. A device according to Claim 1 characterised in that the device is also adapted to measure blood oxygen saturation (SO2).
6. A device according to Claim 1 characterised in that the device is also adapted to measure the haemoglobin index (Hbl) of a patient's blood.
7. A device according to Claim 1 characterised in that the device is adapted for use on a finger or thumb of a patient.
8. A device according to Claim 4 characterised in that the device measures blood glucose in the wavelength range 800nm to 1 lOOnm.
9. A device according to Claim 4 characterised in that the device also measures haemoglobin index (Hbl) and/or oxygen saturation (SO ) of blood at wavelengths of from 1000 to 1200 nm.
10. A device according to either of claims 5 or 9 characterised in that the device also measures SO2 at the isobestic wavelengths.
11. A device according to Claim 10 characterised in that the isobestic wavelengths are 1048 nm, 1172 nm and a further wavelength of 1224 nm.
12. A method of determining blood analyte levels which comprises placing a non-invasive measuring device according to claim 1 against a body part of a patient and using the detector to measure the light transmitted through or reflected from the body part characterised in that the transmitter/detector operates at a wavelength of from 700 to 1200 nm.
13. A method according to Claim 12 characterised in that the blood analyte is glucose.
14. A method according to claim 13 characterised in that the transmitter and detector operate in the near infra red.
15. A method of measuring Hbl and/or SO2 of a patient's blood which comprises placing a device according to claim 1 against a body part of a patient and using the detector to measure the light transmitted through or reflected from the body part characterised in that the transmitter/detector operates at a wavelength of from 700 to 1200 nm.
16. A method according to claim 15 characterised in that the wavelengths are 1084 nm, 1172 nm and 1224 nm.
17. A device according to Claim 1 characterised in that the device is programmed so as to calculate one or more of the haemoglobin index, the oxygen index and the blood oxygen saturation.
18. A computer programme product comprising a computer readable medium having thereon computer programme code means, when said programme is loaded, to make the computer execute a procedure to calculate one or more of the haemoglobin index, the oxygen index and the "whole blood" oxygen saturation in a device according to claim 1.
19. A device or a method substantially as described with reference to the accompanying example.
PCT/GB2001/002516 2000-06-09 2001-06-08 Monitor for non-invasive measurement of blood analytes WO2001093755A1 (en)

Priority Applications (2)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7809418B2 (en) 2007-10-04 2010-10-05 The Curators Of The University Of Missouri Optical device components
US7961305B2 (en) 2007-10-23 2011-06-14 The Curators Of The University Of Missouri Optical device components
US7961304B2 (en) 2007-09-13 2011-06-14 The Curators Of The University Of Missouri Optical device components
US8340738B2 (en) 2008-05-22 2012-12-25 The Curators Of The University Of Missouri Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US8552359B2 (en) 2009-04-01 2013-10-08 The Curators of the Univesity of Missouri Optical spectroscopy device for non-invasive blood glucose detection and associated method of use
WO2015176043A1 (en) * 2014-05-15 2015-11-19 NuLine Sensors, LLC Systems and methods for measurement of oxygen levels in blood by placement of a single sensor on the skin
USD821587S1 (en) 2017-01-26 2018-06-26 Michael J. Vosch Electrode patch array
USD821588S1 (en) 2017-01-26 2018-06-26 Michael J. Vosch Electrode patch array

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992000513A1 (en) * 1990-06-27 1992-01-09 Futrex, Inc. Non-invasive measurement of blood glucose
US5297548A (en) * 1992-02-07 1994-03-29 Ohmeda Inc. Arterial blood monitoring probe
US5435309A (en) * 1993-08-10 1995-07-25 Thomas; Edward V. Systematic wavelength selection for improved multivariate spectral analysis
US5553615A (en) * 1994-01-31 1996-09-10 Minnesota Mining And Manufacturing Company Method and apparatus for noninvasive prediction of hematocrit
WO2000001294A1 (en) * 1998-07-04 2000-01-13 Whitland Research Limited Non-invasive measurement of blood analytes

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992000513A1 (en) * 1990-06-27 1992-01-09 Futrex, Inc. Non-invasive measurement of blood glucose
US5297548A (en) * 1992-02-07 1994-03-29 Ohmeda Inc. Arterial blood monitoring probe
US5435309A (en) * 1993-08-10 1995-07-25 Thomas; Edward V. Systematic wavelength selection for improved multivariate spectral analysis
US5553615A (en) * 1994-01-31 1996-09-10 Minnesota Mining And Manufacturing Company Method and apparatus for noninvasive prediction of hematocrit
WO2000001294A1 (en) * 1998-07-04 2000-01-13 Whitland Research Limited Non-invasive measurement of blood analytes

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7961304B2 (en) 2007-09-13 2011-06-14 The Curators Of The University Of Missouri Optical device components
US7809418B2 (en) 2007-10-04 2010-10-05 The Curators Of The University Of Missouri Optical device components
US7961305B2 (en) 2007-10-23 2011-06-14 The Curators Of The University Of Missouri Optical device components
US9814415B2 (en) 2008-05-22 2017-11-14 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US8340738B2 (en) 2008-05-22 2012-12-25 The Curators Of The University Of Missouri Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US10070809B2 (en) 2008-05-22 2018-09-11 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US9877670B2 (en) 2008-05-22 2018-01-30 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US9566024B2 (en) 2008-05-22 2017-02-14 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US9579049B2 (en) 2008-05-22 2017-02-28 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US9788764B2 (en) 2008-05-22 2017-10-17 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US9629576B2 (en) 2008-05-22 2017-04-25 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US10080515B2 (en) 2008-05-22 2018-09-25 St. Louis Medical Devices, Inc. Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis
US8552359B2 (en) 2009-04-01 2013-10-08 The Curators of the Univesity of Missouri Optical spectroscopy device for non-invasive blood glucose detection and associated method of use
WO2015176043A1 (en) * 2014-05-15 2015-11-19 NuLine Sensors, LLC Systems and methods for measurement of oxygen levels in blood by placement of a single sensor on the skin
USD821587S1 (en) 2017-01-26 2018-06-26 Michael J. Vosch Electrode patch array
USD821588S1 (en) 2017-01-26 2018-06-26 Michael J. Vosch Electrode patch array

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AU7421501A (en) 2001-12-17

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