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Topic of the Month February: New Diagnostic Methods
Electrodes detect malnutrition
Malnutrition among seniors
increases more and more and is
often not caught in time; © SXC
If imminent malnutrition is not caught in time and being treated, it’s not just the patient’s quality of life that decreases; his/her mortality rate also increases. Generally during hospitalizations, a vitamin and protein deficiency is being detected that requires treatment, while the real main illnesses are for example diabetes, cardiac insufficiency or a femoral neck fracture.
If malnutrition is present, the proportion of human adipose (fat) tissue, body fluids and lean tissues such as muscles, bones, skin and organs is disrupted. These factors should each constitute a specific portion of the total body weight – depending on height, weight and age. The ideal result is therefore different for each individual.
Until now malnourishment was primarily determined based on the body-mass index (BMI). However, the BMI only puts the body weight of a person in relation to his/her height. An index with guideline values breaks the results down into underweight, normal weight and overweight. However, this can only serve as a rough guideline since neither figure and gender nor the relative percentage of adipose and muscle tissue are being considered.
The BMI is not appropriate
to diagnose malnutrition;
And this is precisely the starting point from which Doctor Sebastian Wieskotten started in 2009 during the course of his dissertation in the field of automatic control engineering and process automation at the Technical University of Darmstadt, Germany: he developed an assistance system that measures the relative percentage of body fat, body fluid and lean tissue in the body via alternating currents. “The main principle is similar to the common body fat scale“, says Wieskotten. “However, this system goes at least one step further.“
This is the procedure: two electrodes each are attached to hands and feet of the patient. For approximately ten seconds weak, barely noticeable alternating currents with changing frequency flow through the body. During this time the resistance is being measured, which can be determined based on the different water contents in body fat and muscle tissue. Whereas the body fat scale is merely based on bioimpedance analysis, meaning it only measures one frequency, the assistance system Wieskotten developed works based on bioimpedance spectroscopy and thus with multiple frequency.
“When you measure with only one frequency, you cannot distinguish between muscle and fat mass“, Wieskotten explains. “By using the four electrodes on two different reference points and due to the different frequency, higher resolution measurements are possible than are the case with the body fat scale for instance.“ As a result the ascertained data makes a diagnosis easier on whether there is malnutrition or not.
Body fat scales only measure with one frequency and therefor cannot distinguish between muscle and fat tissue; © panthermedia.net/luca de polo
Wieskotten’s assistance system builds on a bioimpedance measurement device that’s already available on the market. “Even though this device is mainly geared toward measurement of fluid balance, it also makes the use to determine nutritional status possible“, says Wieskotten, who now works as a development engineer for Fresenius Medical Care. “Since the primary use of the device is for dialysis patients, currently the application area for fluid measurement is more relevant. “
Wieskotten hopes that in the future, also measuring the nutritional status with this device is going to be expedited in-house and consequently soon renders a market launch of his assistance system possible.