pea_pod_operators_manual_rev_n.pdf
Page 1
OPERATOR’S MANUAL
0413
P/N 210-4004
Page 2
This page left intentionally blank.
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 3
Table of Contents
User Responsibility .....................................................................................................................1
Contact Information.....................................................................................................................2
Software Site License Agreement ...........................................................................................3
Contraindications, Warnings and Cautions ..........................................................................4
SECTION 1
Indication for Use and Introduction ........................................................9
SECTION 2
System Components and Physical Design .........................................11
SECTION 3
Densitometry and the Two-Compartment Model in Infants
Using Body Density to Estimate Body Composition.........................................15
Mass Measurement .........................................................................................17
Volume Measurement .....................................................................................17
Thoracic Gas Volume ......................................................................................19
Surface Area Artifact .......................................................................................20
Clothing and Hair.............................................................................................21
SECTION 4
System Setup
Selecting a Testing Location ...........................................................................23
System Accessories ........................................................................................25
Inspection and Setup.......................................................................................26
SECTION 5
Operating the System
Starting the PEA POD Application...................................................................27
Logging In and Out ..........................................................................................28
Warming-Up the PEA POD .............................................................................30
Monitoring Temperature and CO2 in the PEA POD .........................................31
Navigating the PEA POD Application ..............................................................33
Interrupting PEA POD Activities ......................................................................36
Using the Emergency Off Switch .....................................................................38
Exiting the PEA POD Application ....................................................................39
Shutting Down the PEA POD ..........................................................................39
SECTION 6
Quality Control
Quality Control Procedures .............................................................................41
Subject/Test Preparation .................................................................................44
Body Composition Test Description.................................................................45
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 4
Table of Contents
SECTION 7
Software Activities
Introduction......................................................................................................55
SECTION 8
7.1
Test > Body Composition ..................................................................55
7.2
Test > Mass ......................................................................................73
7.3
Data Management > View Subject Results .......................................80
7.4
Data Management > Modify Subject Results ....................................85
7.5
Data Management > Delete Test ......................................................90
7.6
Data Management > Export Results .................................................97
7.7
Data Management > Database Backup .......................................... 102
7.8
System Setup > Test Profile > Create............................................. 104
7.9
System Setup > Test Profile > Remove ..........................................106
7.10
System Setup > Density Model > Create ........................................ 108
7.11
System Setup > Density Model > Remove......................................110
7.12
System Setup > Scale Checks > Noise and Drift ............................ 112
7.13
System Setup > Scale Checks > Hysteresis ...................................114
7.14
System Setup > Inclinometer .......................................................... 118
7.15
System Setup > Facility...................................................................119
7.16
System Setup > Automatic Backup Directory..................................122
7.17
QC > Analyze Hardware.................................................................. 124
7.18
QC > Calibrate Scale ......................................................................128
7.19
QC > Check Scale ..........................................................................135
7.20
QC > Autorun .................................................................................. 142
7.21
QC > Volume .................................................................................. 152
7.22
QC > Export QC Results ................................................................. 162
Alarms
Alarms Description ........................................................................................165
Possible Alarms............................................................................................. 168
Alarm Table ................................................................................................... 170
Responding to Alarms ...................................................................................171
SECTION 9
System Errors
System Errors Description............................................................................. 173
Possible System Errors .................................................................................174
SECTION 10
Operator Errors
Operator Errors Description...........................................................................177
Examples of Operator Errors.........................................................................178
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 5
Table of Contents
SECTION 11
Maintaining the PEA POD
Service Policy................................................................................................ 179
Operator and Service Maintenance ............................................................... 179
Air Filters Maintenance.................................................................................. 179
Maintenance Schedule .................................................................................. 180
Cleaning Precautions .................................................................................... 181
Cleaning Procedure....................................................................................... 182
Cleaning Solutions......................................................................................... 183
Emergency Tray Removal ............................................................................. 184
SECTION 12
Specifications ........................................................................................... 185
SECTION 13
Warranty .....................................................................................................189
SECTION 14
Additional Unit Information ................................................................... 193
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 6
Table of Contents
Figures
Fig. # Description
2-1
PEA POD, Components (1)...............................................................................................11
2-2
PEA POD, Components (2)...............................................................................................12
4-1
Door Strap Placement .......................................................................................................26
5-1
Login Screen .....................................................................................................................27
5-2
Desktop Icon .....................................................................................................................28
5-3
Main Menu Screen ............................................................................................................29
5-4
Air Circulation System Stabilizing .....................................................................................30
5-5
Temperature and CO2 Display Control Box.......................................................................31
5-6
Temperature and CO2 Display ..........................................................................................32
5-7
Activities by Menu Titles....................................................................................................34
5-8
Command Buttons.............................................................................................................35
5-9
Interrupt Button .................................................................................................................36
5-10
Cancel Test Button............................................................................................................37
5-11
Emergency Off Switch .......................................................................................................38
5-12
Touch Pad Area ................................................................................................................39
6-1
Volume Phantom Placement on the Test Chamber Tray ..................................................43
6-2
Test Chamber Door Closure .............................................................................................47
6-3
Subject Placement on the PEA POD Scale.......................................................................48
6-4
Subject Transfer from PEA POD Scale to Test Chamber .................................................48
6-5
Subject Placement in PEA POD Test Chamber Tray,
Extended from Chamber with Urination Shield Opened ....................................................49
6-6
Test Chamber Tray Extended from Chamber and Empty
with Urination Shield Opened ............................................................................................50
6-7
Subject Placement in PEA POD Test Chamber Tray
Extended from Chamber with Urination Shield Closed......................................................51
6-8
Subject Placement in PEA POD Test Chamber Tray
Inside Chamber with Urination Shield Closed ...................................................................52
6-9
Body Composition Test Results ........................................................................................53
6-10
Body Composition Test Print-Outs ....................................................................................54
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 7
Table of Contents
Figures (cont.)
Fig. #
Description
7-1-1 thru 7-1-18
Test > Body Composition........................................................................55-72
7-2-1 thru 7-2-7
Test > Mass ............................................................................................73-79
7-3-1 thru 7-3-5
Data Management > View Subject Results.............................................80-84
7-4-1 thru 7-4-5
Data Management > Modify Subject Results ..........................................85-89
7-5-1 thru 7-5-7
Data Management > Delete Test ............................................................90-96
7-6-1 thru 7-6-5
Data Management > Export Results .....................................................97-101
7-7-1 thru 7-7-2
Data Management > Database Backup ..............................................102-103
7-8-1 thru 7-8-2
System Setup > Test Profile >Create..................................................104-105
7-9-1 thru 7-9-2
System Setup > Test Profile > Remove ..............................................106-107
7-10-1 thru 7-10-2
System Setup > Density Model > Create ............................................108-109
7-11-1 thru 7-11-2
System Setup > Density Model > Remove..........................................110-111
7-12-1 thru 7-12-3
System Setup > Scale Checks > Noise and Drift ................................112-113
7-13-1 thru 7-13-7
System Setup > Scale Checks > Hysteresis .......................................114-117
7-14-1
System Setup > Inclinometer .....................................................................118
7-15-1 thru 7-15-3
System Setup > Facility ......................................................................119-121
7-16-1 thru 7-16-2
System Setup > Automatic Backup Directory .....................................122-123
7-17-1 thru 7-17-6
QC > Analyze Hardware .....................................................................124-127
7-18-1 thru 7-18-7
QC > Calibrate Scale ..........................................................................128-134
7-19-1 thru 7-19-7
QC > Check Scale ..............................................................................135-141
7-20-1 thru 7-20-16
QC > Autorun......................................................................................142-151
7-21-1 thru 7-21-11
QC > Volume ......................................................................................152-161
7-22-1 thru 7-22-3
QC > Export QC Results.....................................................................162-164
8-1
Remove Subject from the Scale Alarm Message....................................... 165
8-2
Touch Pad Alarm LED ............................................................................... 166
9-1
System Error Displayed on Left Navigation Column and Main Menu......... 173
10-1 thru 10-2
Operator Errors.......................................................................................... 178
11-1
Front Tray Removal ................................................................................... 184
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 8
Table of Contents
This page left intentionally blank.
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 9
User Responsibility
This Product will perform as described in this Operator’s Manual and by accompanying
labels and/or inserts when it is assembled, operated, maintained, and repaired in
accordance with the instructions provided. This Product must be checked periodically as
described in this manual. A defective Product should not be used. Parts that are broken,
missing, plainly worn, distorted or contaminated should be replaced immediately. Should
such repair or replacement become necessary, it is recommended that a telephone or
written request for service advice be made to COSMED USA Inc. This Product or any of
its parts should not be repaired other than in accordance with instructions provided by
COSMED USA Inc., authorized representatives, or by COSMED USA Inc. trained
personnel. The Product must not be altered without the prior written approval of the
COSMED USA Inc. Quality Assurance Department.
The user of this Product shall have the sole responsibility for any malfunction that results
from improper use, faulty maintenance, improper repair, damage, or alteration by anyone
other than COSMED USA Inc. authorized representatives.
Any unauthorized maintenance, repairs, or equipment modifications may void the
product warranty.
Disposal of Waste Equipment by Users in the European Union
This symbol indicates that this product must not be disposed of with other household
waste. Instead, it is your responsibility to dispose of your waste by handing it over to a
designated collection point for the recycling of waste electrical and electronic equipment.
The separate collection and recycling of your waste equipment at the time of disposal will
help to conserve natural resources and ensure that it will be recycled in a manner that
protects human health and the environment. For more information about where you can
drop off your waste equipment for recycling, please contact your local city office, your
waste disposal service, or the place where you purchased the product.
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 1
Page 10
Contact Information
Contact Information
COSMED USA makes every effort to provide prompt and professional support to our
PEA POD Registered Users. Fax and email messages will usually be returned within the
same day.
Address
Americas
Regions Outside of the Americas
COSMED USA, Inc.
COSMED S.r.l.
1850 Bates Avenue
Via dei Piani di Monte Savello, 37
Concord, CA 94520
00041 – Pavona di Albano
Rome - Italy
Telephone
925-676-6002
+39 (06) 931 5492
1-800-426-3763 (Toll Free)
8am – 5pm, M-F (Pacific Time)
Fax
925-676-6005
+39 (06) 931 5480
Web Site
www.cosmed.com
www.cosmed.com
serviceusa@cosmed.com
support@cosmed.com
NOTE:
When at all possible, please be near the PEA POD system when contacting COSMED
USA Customer Support, as access to the computer interfacing with the PEA POD is often
necessary. Please have your PEA POD serial numbers available. They are located on the
back of the PEA POD.
COSMED USA’s Authorized Representative in the European Union is:
EC
Page 2
REP
Medical Device & QA Services Ltd
Altrincham. WA15 7SN.
United Kingdom.
Tel: +44 161 870 6751
Fax: +44 161 903 9787
Email: info@mdqa.co.uk
www.mdqa.co.uk
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 11
Software Site License Agreement
License Terms
This is a legal agreement between you and COSMED USA, Inc. (“COSMED USA”).
COSMED USA grants you the right to use one copy of the PEA POD® Infant Body
Composition System Software (“SOFTWARE”) on a single computer to operate the PEA
POD Infant Body Composition System you have purchased. You may not rent or lease
this SOFTWARE, but you may transfer the SOFTWARE and accompanying written
material on a permanent basis provided you retain no copies and the recipient agrees to
the terms of this Agreement. You may not reverse engineer, decompile, or disassemble
the SOFTWARE until terminated. You may terminate the Agreement by returning to
COSMED USA the original disk and any backup copies. If you breach this Agreement,
COSMED USA can terminate this license upon written notification to you.
Intellectual Property
The SOFTWARE is owned by COSMED USA, Inc. and is protected by United States
copyright laws and other intellectual property rights. Therefore, you must treat the
SOFTWARE like any other proprietary material. Furthermore, you acknowledge that the
license provided under this Agreement is a limited one and in no way shall be construed
to provide you an express or an implied license to any of COSMED USA’s intellectual
property rights other than as expressly set forth above and in no way confers to you or
anyone else any right, title, or interest to the intellectual property rights in the
SOFTWARE.
Controlling Law
This Agreement shall be governed by and construed in accordance with the laws of the
State of California, United States of America.
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 3
Page 12
Contraindications, Warnings, and Cautions
Contraindications
CONTRAINDICATION:
Subjects requiring life support must not be tested in the PEA POD
Warnings and Cautions
WARNING: The PEA POD, while designed to safely contain a subject while performing
body composition tests, is not designed to contain a subject for any length of time beyond
what normal testing would allow. While the temperature in the test chamber is monitored
and controlled for the subject’s comfort, this instrument is NOT an incubator and must
not be used as one.
WARNING: Before, during, and after PEA POD testing the operator must always
monitor the subject and must never leave the subject unattended. The test subject should
be removed from the PEA POD in the event of any alarm condition, system malfunction
or power loss during subject testing.
WARNING: The operator should read and understand the entire PEA POD Operator’s
Manual before conducting any testing. Questions regarding proper operation of the PEA
POD should be referred to a COSMED USA, Inc. authorized representative.
WARNING: The PEA POD contains no operator serviceable components. To prevent
electric shock, do not remove panels or boards. Unauthorized maintenance or servicing
may void product warranty. All servicing should be completed by COSMED USA, Inc.,
authorized personnel only. Failure to use the PEA POD as specified in this Operator’s
Manual may void the product warranty.
WARNING: Grounding reliability is achieved only when this equipment is connected to
a grounded outlet or an equivalent receptacle marked “Hospital Grade”.
Page 4
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 13
Contraindications, Warnings, and Cautions
Warnings and Cautions (cont.)
WARNING: Do not apply excessive lateral force to the PEA POD when the chamber
door is fully opened. Doing so may result in damage to the door hinge, which may
prevent the test chamber door from closing properly. Only transport the PEA POD with
the chamber door closed.
WARNING: Additional transformers, power supplies or extension cords that are not
specified by COSMED USA, should not be connected to the system. Use of unauthorized
equipment may result in damage to the PEA POD system. Use of components other than
those specified by COSMED USA may result in the system not meeting IEC 60601-1
safety standards for medical devices.
CAUTION: The PEA POD is intended to only provide an estimate of a subject’s body
composition (percent fat mass and percent fat free mass). It is not intended to diagnose
nor monitor medical conditions or diseases.
CAUTION: The PEA POD should only be operated by those properly trained on the
procedures and safety guidelines for operating the equipment, including a complete
review of this Operator’s Manual.
CAUTION: Before operation, the operator should ensure all components are secured to
the PEA POD cart, at least two casters are locked, and that the power cable is properly
secured to the PEA POD cart.
CAUTION: The PEA POD is sensitive to temperature changes. Do not place this device
in direct sunlight, near an open window, a heater, air conditioner, or fan. The PEA POD
should be installed in a room with a temperature between 20 and 28 degrees Celsius, and
the room temperature should not vary by more than ±0.5 degrees Celsius during testing.
CAUTION: The PEA POD is sensitive to low frequency acoustic noise. Avoid placing
the PEA POD in the proximity of items that generate low frequency noise (i.e., fans,
doors shutting, and floor vibration).
CAUTION: Physical contact with or movement of the PEA POD during testing may
produce invalid results. The PEA POD should be installed in an area that provides
sufficient operator access to its front and right side, with enough room to allow the door
to open completely and the test tray to fully extend from the chamber.
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 5
Page 14
Contraindications, Warnings, and Cautions
Warnings and Cautions (cont.)
CAUTION: The PEA POD should be installed in a room with a level floor.
CAUTION: The PEA POD should be installed in a room with a relative humidity
between 20 and 70%. Room humidity should not vary more than ±5% relative humidity
during testing. Room barometric pressure should be between 86 and 106 KPa.
CAUTION: The surface area of clothing and hair can have a significant impact on
subject volume measurements. Therefore, all subjects must be tested nude and with their
hair flattened against their head using baby oil or must wear a head cap provided by
COSMED USA, Inc. Failure to follow this protocol may result in inaccurate body
composition test results.
CAUTION: Failure to follow the described procedures for test subject mass measurement
may result in erroneous calculation of body composition by the PEA POD.
CAUTION: Quality Control (QC) procedures should be performed each day before
human testing at the location where testing will occur. Failure to conduct QC procedures
as described in this manual may results in inaccurate body composition test results.
CAUTION: To prevent possibility of injury, keep hands away from the door hinge when
closing or opening the PEA POD chamber.
CAUTION: To prevent possibility of injury, the operator should verify the Test Chamber
Tray is securely placed in the sliding tray frame. The operator should push or pull the
tray slowly when moving the tray in and out of the testing chamber. Only COSMED
USA supplied Test Chamber Trays should be used with the PEAPOD.
CAUTION: To prevent possibility of injury, the operator should verify the subject’s
hands and feet are away from the edges of the tray before closing the urination shield.
CAUTION: The PEA POD and accessories are non-sterile products. Do not attempt to
sterilize any part of the PEA POD, as sterilization may damage the device.
CAUTION: Do not soak parts in cleaning solutions. Always dry parts after cleaning.
Following these two recommendations will greatly extend the life of the parts.
Page 6
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 15
Contraindications, Warnings, and Cautions
Warnings and Cautions (cont.)
CAUTION: Do not allow excess cleaning solution to seep in between parts (especially in
the PEA POD test chamber) where it cannot be easily wiped dry with a cloth.
CAUTION: Use of cleaning solutions not listed in this manual, or chemicals in greater
concentrations than those listed may damage the PEA POD.
CAUTION: Do not load or use software other than that provided by COSMED USA on
the PEAPOD computer system.
CAUTION: To minimize the generation of static electricity, do not polish the top of the
unit or doors with a dry cloth.
CAUTION: The chamber tray and the scale tray should be cleaned after every use. The
disposable scale tray pad should be replaced after the testing of an individual test subject
is complete.
CAUTION: Inspect the test chamber tray for cracks or damage before each use. Do not
use the device if the test chamber tray is damaged in any way.
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 7
Page 16
Contraindications, Warnings, and Cautions
Explanation of Symbols
The following explains the symbols that are found on the PEA POD System:
This symbol alerts the user to the presence of a potential shock hazard. The user should
consult the Operator’s Manual for more information on the potential shock hazard.
This symbol alerts the user of the presence of important operating and/or maintenance
(service) instructions in the PEA POD Operator’s Manual.
This symbol alerts the user to the importance of consulting the Operator’s Manual.
This symbol indicates the “power on” position of the power switch. When the switch is
depressed in this position, it indicates that under normal conditions power is on to the
unit.
This symbol indicates the “power off” position of the power switch. When the switch is
depressed in this position, it indicates that under normal conditions power is off to the
unit.
This symbol indicates the “stand-by” mode switch on the PEAPOD unit.
This symbol represents alternating current.
This symbol indicates that the PEAPOD unit is a Type BF Applied Part.
Page 8
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 17
SECTION 1 – Indication for Use and Introduction
Indication for Use
The PEA POD® Infant Body Composition System (“PEA POD”) is indicated for
measuring the body mass and estimating the body composition (i.e., percent and absolute
amounts of fat and lean body mass) of subjects between 1 and 8 kilograms. It is not
intended for use with subjects requiring life support.
For the purposes of this manual, fat free mass is equivalent to and is used instead of
lean body mass.
Introduction
The PEA POD utilizes the principles of whole body densitometry to estimate the amount
of fat and lean tissue in the body. Whole body densitometry is based on the determination
of body density by measuring body mass and volume. Body mass (weight) is measured
using the PEA POD electronic scale and body volume is measured in the PEA POD test
chamber. Once body density is known, the subject’s percentage and absolute amounts of
fat and fat free mass are automatically calculated using the principles of whole body
densitometry. This is discussed in greater detail in SECTION 3 - Densitometry and the
Two-Compartment Model in Infants.
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 9
Page 18
Page 10
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 19
SECTION 2 – System Components and Physical Design
Figure 2-1 – PEA POD, Components (1)
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 11
Page 20
SECTION 2 – System Components and Physical Design
Figure 2-2 – PEA POD, Components (2)
Page 12
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 21
SECTION 2 – System Components and Physical Design
System Description
The PEA POD components are housed inside or mounted on a movable cart (Figures 2-1
and 2-2). Locking casters allow the PEA POD to be moved and then locked in place for
testing. The cart houses the reference chamber, calibration volume, calibration valve, air
circulation and heating system, scale inclinometer, scale load cell, electronics box,
printer, calibration weight, and volume phantom. The main components of the air
circulation and temperature control system are the heat blanket recirculation fans, the
interior heater fan, and the air circulation tubes. The air circulation and temperature
control systems continuously circulate air from the outside environment to the test
chamber. The temperature of the air circulated within the test chamber is maintained
constant by the system at a temperature of 31ºC.
The test chamber, scale tray, monitor/computer, touch pad, and keyboard are mounted on
the top surface of the cart. A volume-perturbing diaphragm is mounted between the test
and reference chambers. When open, the calibration valve allows the testing chamber to
be connected to the calibration volume. Pressure transducers are connected to the two
chambers.
The test chamber contains a plastic tray on a slide mechanism. The test chamber tray is
designed to position the subject being tested in such a way as to reduce the risk of the
subject falling out of the tray. The test chamber door is kept closed during a test by an
electromagnet. When the electromagnet is energized, the Cancel Test button on the door
is illuminated (blue light). When the door is secured by the electromagnet, which occurs
only when it is energized and engaged by pressing it against its contact block, the door
can be released at any time by pressing the Cancel Test button.
An Emergency Off Switch is located on the top right corner of the front panel and can
be used to turn off the PEA POD in the event of an emergency.
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 13
Page 22
SECTION 2 – System Components and Physical Design
Page 14
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 23
SECTION 3 – Densitometry and the Two-Compartment Model in Infants
Using Body Density to Estimate Body Composition
The application of using body density to derive body composition is referred to as
densitometry. In the PEA POD, an electronic scale integrated within the system is used to
measure the subject’s mass. Air displacement plethysmography is used to measure
subject’s volume. Once the subject’s mass (MB) and volume (VB) are measured, body
density (DB) can be calculated as follows:
DB =
MB
VB
The determination of body composition by densitometry is based on modeling the body
into two compartments, a fat compartment and a fat free mass compartment. The fat free
mass compartment consists of protein, water, mineral, and glycogen. Since the density of
any material is a function of the proportions and densities of its components, the twocompartment model can be defined as:
1
F
FFM
=
+
DB DF DFFM
Where F is fat mass, DF is the density of fat, FFM is fat free mass, and DFFM is the
density of fat free mass. By rearranging this equation and expressing FFM as 1 - F, % fat
can be defined as:
⎡ DF DFFM
⎤
DF
−
% fat = ⎢
⎥ * 100%
(
)
−
−
D
D
D
D
D
F
FFM
F ⎦
⎣ B FFM
Thus, in order to calculate % fat, body density must be measured and the values for the
density of fat and fat free mass assigned.
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 15
Page 24
SECTION 3 – Densitometry and the Two-Compartment Model in Infants
In the PEA POD, % fat is calculated using the previous equation and default values for
the density of fat and fat free mass that are based on the most comprehensive and up-todate results from the scientific literature (1, 2). Because the density of fat remains
constant during life and is equal to 0.9007 kg/L, this value is the default value used by
the PEA POD (2).
Contrary to fat, the density of fat free mass changes from birth to adulthood. Thus, ageand gender-specific densities of fat free mass are used by the PEA POD as defaults based
on results obtained in multi-compartment studies (1, 2).
During the initial days of life, the hydration level of the body fluctuates as the newborn
adapts to life outside of the womb. These fluctuations have been reported (3) and are
accounted for in the PEA POD’s default density models when determining the density of
fat free mass during the first six days of life.
Once % fat is determined, it is then displayed alongside % fat free mass, fat mass, and fat
free mass at the completion of a PEA POD test. The following equations are used to
calculate % fat free mass, fat mass, and fat free mass:
% fat free mass = 100 − % fat
Fat Mass =
(%fat )(MB )
100%
Fat Free Mass = MB − Fat Mass
Page 16
1.
Fomon SJ, Haschke F, Ziegler EE, Nelson SE, 1982. Body composition of reference children from birth
to age 10 years. Am J Clin Nutr 35:1169 –1175
2.
Butte NF, Hopkinson JM, Wong WW, O’Brien Smith E, Ellis KJ, 2000. Body composition during the
first 2 years of life: an updated reference. Pediatr Res 47:578-585
3.
Rodríguez G, Ventura P, Samper MP, Moreno L, Sarría A, Pérez-González JM, 2000. Changes in Body
Composition during the Initial Hours of Life in Breast-Fed Healthy Term Newborns. Biol Neonate
77(1):12-16
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 25
SECTION 3 – Densitometry and the Two-Compartment Model in Infants
Mass Measurement
The mass measurement is performed using the PEA POD’s electronic scale. The
measurement is performed at the beginning of the test sequence, with the value
automatically saved and eventually used in the final calculations.
It is very important to understand that an error in either the mass measurement or the
volume measurement can result in invalid data.
Volume Measurement
The PEA POD uses air displacement plethysmography to measure body volume. This
technique utilizes the relationship between pressure and volume. This relationship allows
for the derivation of an unknown volume by directly measuring pressure.
Boyle’s Law describes the relationship between pressure and volume of air under
isothermal conditions. Under isothermal conditions, the temperature of air remains
constant as its volume changes. Thus, a quantity of air compressed under isothermal
conditions will decrease its volume in proportion to the increasing pressure, or:
P1 V2
=
P2 V1
Where P1 and V1 are initial pressure and volume, and P2 and V2 are final pressure and
volume. The air in the lungs and on the surface of all materials (including skin, clothing
and hair) behaves isothermally.
PEA POD® Infant Body Composition System Operator’s Manual – P/N 210-4004 Rev. N - DCO 1745
Page 17