CROSS REFERENCE TO RELATED APPLICATIONS
This application is based on and claims domestic priority benefits under 35 U.S.C. 120 of U.S. Provisional patent application 61/328,344, filed 27 Apr. 2010. The entire Provisional application is hereby incorporated by reference herein.
FIELD OF THE INVENTION
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This invention relates to the medical field and the treatment of specified diseases and, in particular, to a device for non-invasive measurement of the blood glucose level of a subject patient.
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OF THE INVENTION
Diabetes and its complications impose significant economic consequences on individuals, families, health systems and countries. The annual expenditure for diabetes in 2007 in the USA alone was estimated to be over $170 billion, attributed to both direct and indirect costs (American Diabetes Association. Economic costs of diabetes in the U.S. in 2007. Diabetes Care. 2008 March, 31(3): 1-20). In 2010, Healthcare expenditures on diabetes are expected to account for 11.6% of the total worldwide healthcare expenditure. It is estimated that approximately 285 million people around the globe will have diabetes in 2010, representing 6.6% of the world's adult population, with a prediction for 438 million by 2030 (International Diabetes Federation. Diabetes Atlas, Fourth edition. International Diabetes Federation, 2009).
In the recent years, research has conclusively shown that improved glucose control reduces the long-term complications of diabetes (DCCT Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. North England Journal of Medicine. 1993 Sep. 30; 329(14): 977-986; UKPDS Group: Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in subjects with type 2 diabetes (UKPDS33). The Lancet. 1998 Sep. 12; 352(9131): 837-853). According to the American Diabetes Association (ADA), self-monitoring of blood glucose (SMBG) has a positive impact on the outcome of therapy with insulin, oral agents and medical nutrition (American Diabetes Association. Clinical Practice Recommendations, Standards of medical care in diabetes. Diabetes Care. 2006 Jan. 29: S4-S42). In its publication “Consensus Statement: A European Perspective”, the Diabetes Research Institute in Munich recommends SMBG for all types of diabetes treatment approaches, in order to achieve proper glucose control and values which are close to normal, without increasing the risk of hypoglycemia (Schnell O et al., Diabetes, Stoffwechsel and Herz, 2009; 4:285-289). Furthermore, special guidelines with proper recommendations were issued recently by the International Diabetes Federation (IDF), to support SMBG for non-insulin treated T2DM patients (Recommendations based on a workshop of the International Diabetes Federation Clinical Guidelines Taskforce in collaboration with the SMBG International Working group. Guidelines on Self-Monitoring of Blood Glucose in Non-Insulin Treated Type 2 Diabetics. International Diabetes Federation, 2009).
SMBG presents several benefits in both diabetes education and treatment. It can help facilitate individuals' diabetes management by providing an instrument for objective feedback on the impact of daily lifestyle habits, individual glucose profiles, including exercise and food intake impact on that profile, and thereby empower the individual to make necessary changes. Moreover, SMBG can support the healthcare team in providing individually tailored advice about life style components and blood glucose (BG) lowering medications, thus helping to achieve specific glycemic goals.
The inconvenience, expenses, pain and complexity involved in conventional (invasive) SMBG, however, lead to its underutilization, mainly in people with type 2 diabetes (Mollema E D, Snoek F J, Heine R J, Van der Ploeg H M. Phobia of self-injecting and self-testing in insulin treated diabetes patients: Opportunities for screening. Diabet Med. 2001; 18:671-674; Davidson M B, Castellanos M, Kain D, Duran P. The effect of self monitoring of blood glucose concentrations on glycated hemoglobin levels in diabetic patients not taking insulin: a blinded, randomized trial. Am J Med. 2005; 118(4):422-425; Hall R F, Joseph D H, Schwartz-Barcott D: Overcoming obstacles to behavior change in diabetes self-management. Diabetes Educ. 2003; 29:303-311). Availability of an accurate, painless, inexpensive and easy to operate device will encourage more frequent testing (Wagner J, Malchoff C, Abbott G. Invasiveness as a Bather to Self-Monitoring of Blood Glucose in Diabetes. Diabetes Technology & Therapeutics. 2005 August; 7(4): 612-619; Soumerai S B, Mah C, Zhan F, Adams A, Baron M, Fajtova V, Ross-Degnan D. Effects of health maintenance organization coverage of self-monitoring devices on diabetes self-care and glycemic control. Arch Intern Med. 2004; 164:645-652), leading to tighter glucose control and delay/decrease of long-term complications and their associated healthcare costs.
Non-invasive (NI) glucose monitoring can decrease the cost of SMBG and increase meaningfully the frequency of testing. The main concern in NI methods is to achieve high accuracy results, despite the fact that no direct blood or interstitial fluid measurement is performed.
Therefore, as is well known in the medical arts, one of the more important blood components to measure for diagnostic purposes is glucose, especially for diabetic patients. The well-known and typical technique for determining blood glucose concentration is to secure a blood sample and apply that blood to an enzymatically medicated colorimetric strip or an electrochemical probe. Generally, this is accomplished from a finger prick. For diabetic patients who may need to measure blood glucose a few times a day, it can immediately be appreciated that this procedure causes a great deal of discomfort, considerable irritation to the skin and, particularly, the finger being pricked, and, of course, infection.
For many years, there have been a number of procedures for monitoring and measuring the glucose level in humans and animals. These methods, however, generally involve invasive techniques and, thus, have some degree of risk, or at least some discomfort, to the patient. Recently, some non-invasive procedures have been developed, but still they do not always provide optimum measurements of the blood glucose. At present, there has been no practical confirmed solution.
Most non-invasive monitoring techniques have focused on using incident radiation, which is capable of penetrating tissue and probing the blood. Currently known approaches to non-invasive glucose measurement are mainly based on optical technology. The less successful and relatively uncommon electrical measurements focus upon the dielectric properties of water solutions in a given frequency range, typically between 1-50 MHz. In one form or another, such methods attempt to monitor the influence of glucose or other analyzed concentration upon the dielectric frequency response of either the glucose itself or the secondary effect on the water.
Although investigations have been made into the use of acoustic monitoring, past studies have been primarily directed to the differences in acoustic velocity between organs. These studies have attempted to correlate acoustic velocity changes with chronic or continuous disease states. In addition, there is a large body of medical and scientific literature pertaining to the use of acoustic absorptive and scattering properties of organs for imaging, therapeutic and even diagnostic objectives.
In the prior art techniques, only one parameter is measured. Thus, the possibility of an error is increased.
Freger (U.S. Pat. No. 6,954,662) discloses a non-invasive technique and methods (but not devices) for measurements of the speed of sound through the blood, the conductivity of the blood, and the heat capacity of the blood. Thereafter, the glucose level for each of the three measurements is calculated and the final glucose value is determined by a weighted average of the three calculated glucose values.
While Freger mentions that measurements may be taken of the speed of sound through the blood, the conductivity of the blood, and the heat capacity of the blood, there is no disclosure of how any device can be constructed for effecting such measurements. The herein disclosed and claimed invention, therefore, is an improvement of Freger and specifies a specific device in which these measurements can be effected.
Therefore, there is a need for a more accurate non-invasive device for measuring glucose level, by means of monitoring multiple parameters in a single unitary device. It is, therefore, an object of the present invention to provide a device for non-invasively measuring glucose level in a subject. These objects are achieved by the features of the claims and the following description, in particular by the following preferred aspects of the invention relating to preferred additional and/or alternative embodiments.
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OF THE INVENTION
This and other objects of the Invention are achieved by a device, preferably an unitary device, that is capable of non-invasively measuring the body\'s glucose level by three distinct protocols.
In particular, the device according to the present invention preferably includes a Main Unit, containing hardware and also the software applications, and preferably an external unit(s)/external device(s) (preferably an ear clip) for affixment to the patient. The external unit comprises first and second portions which are connected to each other, wherein the first and second portions are located on opposing sides of a part of the subject, to which said external unit is affixed. For instance, when the external unit is affixed to a patient\'s ear lobe, the two opposing sides are located on the two opposing sides of the ear lobe, respectively
It is preferable to incorporate in the unitary external unit at least one of the following three elements, which effect three separate and distinct non-invasive measurements of glucose. Additionally, it is further preferred to provide at least two or three elements to effect two or three separate and distinct non-invasive measurements of glucose, respectively. According to a preferred embodiment of the present invention, at least three different elements to effect three separate and distinct non-invasive measurements of glucose are provided within a single, unitary external device, e.g., within a single housing.
It should also be appreciated and understood that each of the measurement channels is new and novel in and of themselves. Hence each measurement channel may be used in isolation by itself (or with still other measurement channels). By combining the three measurement channels in one unitary device, measurements are obtained from three separate and unique measurement channels, thereby optimizing the final measurement.
For non-invasive measurement by use of ultra sound, preferably a transmitter (such as an ultra sound transmitter) and a receiver (such as an ultrasound receiver) are mounted on opposing sides of the external unit. When the external unit is fitted on the patient, a portion of the patient\'s body (such as an ear lobe) is situated between the transmitter and receiver. Upon receipt of the resultant signal, after it passes through the patient, the receiver sends the signal to the Main Unit for processing by appropriate algorithms. In some embodiments, membranes may be used to cover and protect the transmitter and receiver.
To effect an Electromagnetic measurement, a capacitor is defined in the external unit. The capacitor plates are positioned on opposing sides of the external device and the body part (such as an ear lobe) disposed between the parts of the external unit serves as the dielectric. In some cases the membranes used to shield or cover the transmitter and receiver can serve also as the capacitor plates.
The third technology is based on thermal technology to measure the glucose level. For this purpose, preferably a heater and a sensor are provided at the external device. It is preferred to provide the heater and the sensor (thermal sensor) at opposing sides of the external device. According to another preferred embodiment, however, it is preferred to mount the heater and the sensor on the same side of the two opposing sides, e.g., on the tip of one side of the external unit a heater and sensor are positioned.
The objects of the present invention are solved, for example, by the following aspects of the invention.
According to a first aspect, a unitary device for non-invasively measuring glucose level in a subject comprises: ultrasonic piezo elements positioned on opposing portions of the device and surrounding a part of the subject\'s body to which the device is attachable; capacitor plates positioned on opposing portions of said device and surrounding said part of the subject\'s body to which the external means is attachable, and auto-oscillating means connected to said capacitor plates; and a heater and a sensor positioned in close juxtaposition to said part of the subject\'s body to which the device is attachable.
In one preferred embodiment, the device further comprises an external means (such as an ear clip) for affixment to the subject\'s body, wherein the ultrasonic piezo elements, the capacitor plates and the heater and the sensor being contained within said external means.
There may also preferably be a main unit for controlling measurements and calculating glucose level; and, means for electrically connecting the main unit and the external means, either galvanic or wireless.
Preferably, membranes cover the ultrasonic piezo elements.
The ultrasonic piezo elements may preferably include a transducer and a receiver.
Preferably, the capacitor plates comprise membranes. In such an embodiment, the membranes may also cover the ultrasonic piezo elements.
A preferred embodiment may include means for determining a distance between opposing portions of said external means. In some embodiments, this means may include a magnet and a sensor.
There may also preferably be an adjustment screw setting the distance between opposing portions of said external means.
In some embodiments, an ambient temperature sensor may be included.