This document discusses body composition monitoring using bioelectrical impedance analysis. It begins by defining body composition as the relative amounts of fat mass and fat-free mass in the body. It then describes several methods for assessing body composition including BMI, circumference measurements, hydrodensitometry, air displacement, skinfold tests, bioelectrical impedance analysis (BIA), CT, PET, MRI and spectroscopy, and DEXA. The document focuses on BIA, explaining its history, principles, limitations, the use of spectroscopy, and types of analyzers including the BCM machine. It concludes by noting factors that should be considered for accuracy when performing BIA tests.
12. ASSESSING BODY COMPOSITION.
Height, weight,
BMI.
Waist and hip
circumference
Hydrodensitomerty
Air Displacement
method
SKinfold
Assessment
BIo electrical
Impendance
CT, PET
MRI and
Spectroscopy
DEXA
18. BIO ELECTRICAL IMPENDANCE
It is a simple, quick, non-invasive and inexpensive method of analysing body composition
by passing a painless electric current into the body and measuring the impendence .
The impedance readings are then translated using validated algorithms into estimations of
body fat, lean muscle and water.
19. HISTORY
• KENNETH COLE AND HIS BROTHER ROBERT(
ELECTRICAL PROPERTIES OF CELL MEMBRANE )
INVESTIGATED FREQUENCY - DEPENDENT
IMPENDANCE OF CAPACITIVELY COATED
SPHERES IN SUSPENSION (COLE 1928 ) AND
DESCRIBED THE CIRCULAR ARC ,NOW KNOWN AS
COLE PLOT THAT IS FOUND IMPENDANCE AT
DIFFERENT FREQUENCIES IS PLOTTED ON AN
ARGAND DIAGRAM.
20. HISTORY
Thomasset developed the concept of differentiating
ECF and TBW with needle electrodes by measuring at
high and low frequency ( Thomasset 1963 )
Later needle electrodes replaced by the less invasive
surface electrode ( Hoffer et al., 1969 )
22. BIO
ELECTRICA
L
IMPENDAN
CE
Single Frequency (50 KHz )
Dual Frequency (5/50 KHz)
Multiple Frequency (5/50/100/200KHz)
Spectrum of Frequency - ( Bio impendance Spectroscopy )
50 to 256 frequency Ranging from ( 0 to 1000KHz)
23. LIMITATIONS.
SINGLE FREQUENCY AND WHOLE
BODY APPROACH IS NOT GOOD TO
GIVE ACCURATE RESULTS.
LATER SCIENTISTS DEVELOPED THE
EMPIRICAL ESTIMATION FORMULAS
TO COMPENSATE IT.
BUT STILL IT IS NOT ENOUGH TO
GIVE ACCURATE RESULTS.
29. BCM - FRESINUS MACHINE.
The BCM - Body Composition Monitor
employs the latest bioimpedance
spectroscopy techniques. It measures
at 50 frequencies over a range from 5
to1000 kHz to determine the electrical
resistances ofthe total body water
(TBW) and the extracellularwater
(ECW).
While high-frequency current passes
through thetotal body water, low-
frequency current cannot penetrate
cell membranes and thus flows
exclusively extra cellular water.
30. To obtain the clinically relevant output parameters, two advanced physiological models are
used in the BCM - Body Composition Monitor:
• A volume model describing electrical conductance in a cell suspension enabling the total
body water and extracellular water as wellas the intracellular water (ICW) to be calculated2
• A body composition model calculating the threeprincipal body compartments
overhydration,lean tissue and adipose tissue from ECW and TBW information.
31. How is the BCM – Body Composition Monitor validated?
All output parameters have been validated against the gold standard reference methods in various studies involving more than 500 patients
and healthy controls.
These reference methods include:
• Extracellular water – bromide dilution
• Intracellular water – total body potassium (TBK)
• Total Body Water – deuterium dilution
• Lean Tissue Mass – Dual Energy X-ray
Absorptiometry (DEXA)
• Adipose Tissue Mass – 4-compartment modelling , DEXA, air displacement plethysmography
and underwater weighing
• Body Cell Mass – magnet resonance tomography, TBK
• Overhydration – by expert clinical assessment
32. FACTORS
NEED TO
CONSIDERE
D FOR
ACCURACY
Correct wt and
Ht.
Patient need to
rested for 3 min
in supine to
ensure equal
distribution of
water
Need to wait for 2
to 3 min after
applying
electrodes.
Pateient should
not drink or eat
before one hr of
analysis
Hands and feet
apart , not close
to body.
No exercise
before analysis
Changes in
temperature and
skin condition
alter the results
Dont use mobile
phone, router ,
laptop near to
measurement
area
Dont do to
permcath pts on
dialysis treatment
Amputated pts
correction to be
made according
to reference list.
34. COLE PLOT
INTERPRETATI
ON
THE ACTUAL POSITION OF COLE PLOT
DEPENDS UPON
•UNDERWEIGHT (THIN) OR
OVERWEIGHT (OBESE)
•DEHYDRATION OR
OVERHYDRATION
SHAPE AND
HYDRATION.
35.
36. HIGHEST REACTANCE AND A
FREQUENCY OF ABOUT 5O
KHZ
HIGHEST RESISTANCE WITH
LOW FREQUENCY
37.
38. MORPHOLOGY OF COLE PLOT
OVERHYDRATIO
N
DEHYDRATION OBESE THIN
SHORT TALL LEFT RIGHT
MORE FLUID LESS FLUID MORE FAT &
CROSS-
SECTIONAL
AREA
LESS FAT
&CROSS-
SECTIONAL
AREA
39.
40.
41. Q = 96.569
• QUALITY IS NOT A MEASURE OF QUALITY
• IT RELECTS HOW FAR THE MEASURED POINTS IN THE FITTED CURVE OF THE
COLE PLOT
• SMALL CURVE DOTS ARE SQUASHED TOGETHER WILL GIVE HIGHER Q READING,
ACTUALLY THERS IS CLEAR PROBLEM WITH THE DATA.
• TALL CURVE WHRE THE DOTS ARE SPREADED OUT , WILL GIVE LOWER Q
READING WHEN THE DATA IS GOOD.
42. GOOD QUALITY READING
• WELL SHAPED
• SYMMETRIC COLE PLOT
• REPRODUCIBLE
• REALISTIC
• CONSISTENT WITH HISTORICAL DATA.
43. ALWAYS REPEAT THE MEASUREMENT
• DO THE MEASUREMENT TWICE
• TO CHECK THE REPRODUCIBILITY
• CHANGE IN OH UPTO 10 % IS ACCETABLE.