Product Manual

Medical basis • 45
English
6. MEDICAL BASIS
This section briefly describes the principles of bioimpedance analysis, as well
as the content and medical objectives of the evaluation modules pre-set in
this device.
For additional information, we refer you to the appropriate professional
literature.
6.1 Bioimpedance analysis (BIA)
Classic body composition analysis The current “gold standard” for body composition analysis comprises a com-
bination of methods, some of which are highly technical and very time-con-
suming, for determining individual parameters. The parameters are
considered in combination with the weight and height of the patient. This
allows the nutritional condition and health risk of the patient to be assessed
on an individual basis. The table below provides an overview of the gold
standard parameters and the corresponding determination method.
A high degree of technical complexity is required to determine fat mass. The
table below serves as an overview of this also.
The high technical and financial outlay, combined with considerable time and
space requirements, mean that the “gold standard” is unsuitable for day-to-
day operations in clinics and medical practices.
Diaphragm
Computer
Window
Test chamber
Reference
chamber
Electronics
Low
pressure
High
pressure
High
pressure
Moving diaphragm produces
complementary pressure changes in the chambers
Low
pressure
Scale
Air displacement plethysmography (ADP)
Dual energy X-ray absorptiometry (DEXA)
Parameter Method
Total body water (TBW) Dilution method, tracer: deuterium
Extracellular water (ECW) Dilution method, tracer: sodium bromide
Fat mass (FM)
Calculation based on the four-component
model
a
from the variables: body volume,
bone minerals, weight and total body water.
a.Fuller NJ, Jebb SA, Laskey MA, Coward WA, Elia M. Four-component model
for the assessment of body composition in humans: comparison with alter-
native methods, and evaluation of the density and hydration of fat-free mass.
Clin Sci 1992; 82: 687-693.
Visceral adipose tissue
(VAT)
Magnetic resonance tomography (MRT)
Fat-free mass (FFM) Difference between weight and fat mass
Skeletal muscle mass
(SMM)
Magnetic resonance tomography (MRT)
Parameter Method
Total body water (TBW) Dilution method, tracer: deuterium
Body volume
Densitometry, e.g. air displacement
plethysmography (ADP)
Bone minerals Dual energy X-ray absorptiometry (DEXA)