Friendly approach for diabetics

biomedical11

عضو جديد
إنضم
16 يناير 2012
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Friendly approach for diabetics

Diabetes mellitus is a disease that often causes difficulties to maintain a normal level of blood glucose concentration in a patient, mainly because either insufficient insulin is produced by the beta cells in the pancreas, or the body is unable to effectively utilize that insulin. The problem is that high blood glucose levels induce secondary complications, such as nephropathy and retinopathy, and low levels lead to hypoglycaemic events, which can lead to insulin shock as well as death. It is a very frequent chronic disease that in the last years has reached the proportion of an epidemy. The prevalence of diabetes for all age groups worldwide was estimated to be 7.8% by 2030 by the International Diabetes Federation (IDF Diabetes Atlas). The total number of people with diabetes is projected to rise from 171 million in 2000 to 439 million by 2030.
Noninvasive blood glucose sensors are still under development stage considering that they are far from being suitable for use in anartificial pancreas. The latter has three main parts: the blood glucose sensor, the insulin pump and the controller. However, for the biosensor analyzed here, some common failures such as signal shifts and unreal picks were found. They must be taken into account, for computing the correct insulin dosage for diabetic persons. Hence, a fault detection system based on discrete wavelets transform (DWT) is applied here. The main idea is, when the fault occurs, to do a proper measurement compensation for sending the corrected value to the predictive functional controller (PFC) algorithm. The study is done by reproducing the fault on the blood glucose measurements. They are obtained from a mathematical model of the endocrine system of an adult diabetic patient. This model was approved by the FDA in 2008. Then, the simulation environment includes faulty blood glucose measurements and a fault diagnosis and identification (FDI) system based on DWT. The FDI system gives to the PFC algorithm the correct information to turn it into a fault-tolerant controller (FTC).
There are many methods available for glucose determination, with the majority based on enzymatic reactions. In order of accurateness, the most common are directly measuring glucose in blood (invasive), measuring glucose in the interstitial fluid (minimally invasive), and estimating glucose using other corporal fluids like oral mucosa, aqueous humor of the eye, sweat, urine, saliva, tears, and so forth (noninvasive). The technologies employed could be polarimetry, electromagnetism, ultrasound, Raman spectroscopy, reverse iontophoresis, impedance spectroscopy, and so forth.
Why noninvasive measurement is important is evident; the pain caused by finger pricking or invasive sensors is the main reason. It is very common that minimally invasive glucose sensors cause irritation, infections, or even bruising. These sensors have to be renewed every 5 or 6 days, and, at worst, may require that the sensor be recalibrated at frequent intervals with a fingerstick meter. Noninvasive monitoring avoids all these disadvantages but is not as accurate as the invasive technologies.
The ideal glucose sensor [8] should be selective for glucose with a fast, predictable response to changing glucose concentrations. It should depend on a reversible and reproducible signal to provide results, and sensor fabrication must be reproducible and cheap on a large scale. It should have a long operational lifetime under physiological conditions, but most of all must be acceptable to the patient. Therefore, it should be noninvasive, should not require user calibration, and would ideally provide real-time continuous information regarding glucose. Continuous glucose monitoring provides data about the direction, magnitude, duration, frequency, and potential causes of fluctuations in blood glucose levels, providing patients with real-time data and alarms at times of hypoglycaemia or rapid glucose change. Continuous glucose monitoring is also required to implement closed-loop control.

The main goal is to deliver the correct insulin dosage to the patient. The new technology is simply a device that provides an automatic glucose measurement. It checks the glucose concentration in the skin, it wears on the hand like a wrist watch. Moreover, the new model doesn’t need any blood sample from the patient. Up until now, all of the glucose testing depends on blood samples, but the new model adopted in sugar testing on the interstitial fluid in skin, here the sugar level will be extracted from the interstitial fluid by using a kind of electrical current. The device actually obtains the measurement of the glucose from the skin directly by using a noninvasive biosensor which will be stuck behind the watch and contact the skin. Moreover, the noninvasive biosensor is an integrated chip which detects the glucose level from the skin by using electrical signals. The device provides patients with continuous measurements, up to 7 readings per hour over 24 hours. Also, the device contains a built-in alarm which warns the diabetics in case of suspicion if the sugar level is below the standard level or above a “hyperglycemia or hypoglycemia” situations. The new device consists of different electrical chips which are designed to direct the electrical signal that is used to detect the glucose level. Moreover, these electrical chips are controlling a watch applications and noninvasive biosensor functions. It gives continual and frequent measurements in just few seconds the results will be shown in the display monitor. The noninvasive biosensor that is used in the new model has two different methods to work, so I will illustrate these two methods, their procedures and as my duty in our department to chose the ideal method for my new biosensor relying on the characteristic of using less time possible.
 
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