Measuring change in limb volume to evaluate

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Science, Practice and Education
adrid · Spain
EWMA n GNEAUPP 2014
Submitted to EWMA Journal, based on a presentation given at a free paper
session (Free paper
session: Quality of life) at
the EWMA - GNEAUPP
2014, Madrid
Measuring change in
limb volume to evaluate
lymphoedema treatment
outcome
ABSTRACT
The accurate, non-invasive measurement of limb
volume in patients with lymphoedema is important in
the clinical and research setting.
Aim
This paper provides an overview of the practical
approaches to assessing limb volume and calculating
changes in limb volume after treatments in patients
with unilateral lymphoedema.
Methods
Techniques for assessing limb volume are described,
and a case study example is presented. A compression
bandaging system comprised of a foam roll and cohesive, inelastic bandages was applied to 9 patients with
unilateral lymphoedema on 6 occasions over a 12-day
treatment period. Two parameters for measuring the
changes in limb volume after the course of treatment
were used to evaluate treatment outcomes.
n Parameter 1: percentage change in excess
limb volume over time.
n Parameter 2: percentage change in absolute
limb volume over time.
Results
In 9 patients, the mean percentage change in excess
limb volume at Day 12 was 35%, and the mean percentage change in absolute limb volume was 8%.
Conclusions
The two parameters for calculating changes in limb
volume are not interchangeable. Parameter 1 is only
suitable for patients with unilateral lymphoedema, but
provides the information on the reduction of lymphoedema (excess) volume. Parameter 2 can be used
for patients with bilateral lymphoedema, where no
comparator or unaffected limb is available. Both
parameters should be reported in research, and both
limbs should be measured, if possible. However,
Parameter 2 should be used with caution, as the
percentage change is based on the whole limb volume,
rather than the more accurate excess limb volume as
a measure of lymphoedema.
INTRODUCTION
A key characteristic of lymphoedema is increased
limb volume. The accurate, non-invasive measurement of limb volume is essential in the clinical
and research setting. The change in limb volume
is an important treatment outcome in determining the effect of decongestive treatments, such as
compression bandaging. This manuscript provides
an overview of the practical approaches for assessing limb volume and describes two parameters
for calculating the changes in limb volume over
time. Nine patients with unilateral lymphoedema
participated in an audit of a lymphoedema bandaging system comprised of a foam roll and cohesive inelastic bandages (Fig. 1). This bandaging
system was applied on 6 occasions over a 12-day
treatment period.
WHY MEASURE LIMB VOLUME?
Measuring limb volume can be a useful tool in
establishing the extent and stage of lymphoedema
and identifying the treatment outcomes1,2. In patients with unilateral lymphoedema, the difference
between the affected and unaffected limb volume
is expressed as the excess limb volume, which is
often reported as a percentage of the volume of
the unaffected limb (Table 1). A grading system
for unilateral lymphoedema based on the excess
limb volume has been established2:
Anne F. Williams
PhD, MSc, RN, DN, Dip
Nurse Ed
Lecturer in Nursing
Queen Margaret University
Edinburgh
EH21 6UU
Scotland
Justine Whitaker
MSc, RN
Director and Lymphoedema Nurse Consultant,
Northern Lymphology Ltd,
Senior Lecturer, University
of Central Lancashire, UK
Correspondence:
anne@esklymphology.
co.uk
Financial support was
provided from Activa
Healthcare for the
bandaging audit and the
original presentation at
EWMA 2014. This
manuscript is based on
the original presentation.
n
<20% = mild lymphoedema
n 20–40% = moderate lymphoedema
n >40% = severe lymphoedema
In patients with bilateral lymphoedema, monitoring the volume of each limb can provide information on the treatment and self-management
outcomes over time, thus enabling both patients
and practitioners to recognise any change in individual limb size. However, as there is no unaf
EWMA Journal 2015 vol 15 no 1
27
Figure 1: Application of the bandaging
system, which was comprised of the spiral application of a foam roll* and the
figure-of-eight application of the cohesive, inelastic bandages**
* Rosidal Soft, Lohmann & Rauscher, Rengsdorf, Germany ** Actico, Activa Healthcare, Staffordshire, United Kingdom
fected control limb, the
actual (excess) volume
of lymphoedema cannot be accurately established in someone with
bilateral swelling. Similarly, no fully validated
and reliable method exists for establishing the
lymphoedema volume
in patients with swelling in the head, neck,
genitalia, and trunk2.
TECHNIQUES FOR
MEASURING LIMB
VOLUME
Various techniques for
measuring limb volume
have been reported in
the literature.
n Tape measure
n Water displacement
n Perometer
TAPE MEASURE
This is the most practical and portable technique in the therapeutic
setting. Most commonly, the limb is marked
and measured at 4-cm
intervals1. Circumferential measurements
are recorded (Table 1),
and measurements can
be compared over time
for each point, thereby
28
Table 1: Recording circumferential measurements in Patient A (a woman with lower limb
lymphoedema). The cylinder equation is used.
Before treatment
After treatment
Right limb
Left limb
Right limb
Left limb affected
unaffected (cm) affected (cm)
unaffected (cm)
(cm)
DISTAL
21.7
29.0
21.4
25.5
24.0
33.1
23.6
28.5
28.4
38.7
28.1
32.6
33.4
42.2
33.3
38.6
35.5
35.9
43.6
37.5
36.0
44.0
35.8
40.0
35.2
43.1
35.0
39.5
34.0
40.3
37.6
33.7
34.3
41.0
34.0
38.4
Distal limb volume0
2,904
4,524
2,856
3,651
(ml)0
Excess volume (ml)0
1,620
795
% excess0
56%
28%
PROXIMAL
38.5
44.0
38.8
41.5
41.2
46.3
41.5
44.1
44.0
49.8
43.2
45.5
48.0
52.0
48.0
47.0
51.9
51.9
51.5
51.6
53.0
57.0
53.2
56.6
55.5
57.9
56.5
57.7
57.5
59.8
57.9
60.2
Proximal limb0
6,145
7,045
6,182
6,609
volume (ml)0
Excess volume (ml)0
899
427
% excess0
15%
7%
Total limb volume0
(ml)0
Excess volume (ml)0
% excess0
9,050
11,569
9,038
10,260
2,519
28%
-
1,222
14%
-
EWMA Journal 2015 vol 15 no 1
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Science, Practice and Education
Table 2: Two equations for calculating limb volume
Volume of a cylinder: the limb is viewed as a series of
cylinder-shaped segments.
Volume of each segment = C²/π
C is the circumference at the midpoint of a segment
with a length of 4 cm. Therefore, the starting point
for the first measurement is 2 cm above the wrist or
ankle.
Total limb volume is determined by the sum of the
segment volumes.
Volume of a truncated cone: the limb is viewed as a
series of truncated cone or frustrum-shaped
segments.
Volume of each segment = L/12π (C1² + C1 C2 + C2²)
C1 and C2 are the circumferences at either end of a
segment length (L). The starting point for the
measurement is at the wrist or ankle, which
represents the first point of the distal truncated cone.
Total limb volume is determined by the sum of the
segment volumes.
Table 3: Limb volume calculations before treatment in Patient A
Total limb volume
The calculation of total limb volume (ml):
Right leg: 9,050
Left leg: 11,569
Excess limb volume comparing affected and unaffected limbs
The difference between the limb volume of the affected and unaffected limbs in a patient
with unilateral lymphoedema (ml):
11,569 – 9,050 = 2,519
Percentage difference in excess volume
The excess limb volume is expressed as a percentage of the unaffected limb volume. This 3
indicates how much larger the affected limb is compared to the unaffected limb.
2,519 x 100 = 28%
9,050
Volume of different segments of the limb
The limb is divided into the distal and proximal segments, and the total volume, excess
volume, and percentage excess volume are reported for each segment. This is particularly
useful if the swelling is not evenly distributed (for example, below the knee only).
Distal segment volumes (ml)
Proximal segment volumes (ml)
Affected distal segment: 4,524
Unaffected distal segment: 2,904
Excess volume of distal segment: 1,620
% excess volume of distal segment:
1,620 x 100 = 56%
2,904
Affected proximal segment: 7,045
Unaffected proximal segment: 6,145
Excess volume of proximal segment: 899
% excess volume of proximal segment:
899 x 100 = 15%
6,145
EWMA Journal 2015 vol 15 no 1
giving precise information on
the distribution of swelling
and changes in limb circumference. Any change in limb
circumference may indicate an
increased or reduced fluid volume. These changes may also
be influenced by the alterations
in muscle mass, fat tissue, and
tissue fibrosis. As such, an unaffected limb should always be
measured as the control, as symmetrical change can be expected
in response to factors, including
exercise and weight loss.
Circumferential measurements can be entered into computer software programmes or
pre-programmed calculators to
calculate limb volume and, in
unilateral swelling, excess limb
volume. Most commonly, two
formulae are used to calculate
the volume (Table 2), although
the limb is rarely shaped like a
true cylinder or truncated cone
(frustrum). The calculation of
the limb volume, excess volume, and percentage excess volume can be established for the
whole limb, distal segments, and
proximal segments, thus providing specific information on the
distribution of oedema within
the limb (Table 1). In the example shown in Table 1, the excess volumes before treatment at
the distal and proximal sections
of the limbs are very different
(56% and 15%, respectively).
This indicates an uneven distribution of swelling, which is
not evident in the whole limb
volume excess figure of 28%.
When the measurement
method is precise and standardised, evidence indicates that circumferential methods are valid
and reliable3,4,5 (Table 4). The
actual limb volume achieved will
depend on the size and shape
of each limb segment and the
method of calculation6-8. The
formulae (cylinder or truncated
29

Table 4: Tips for achieving accuracy using the tape measure method
• Consistent limb position
• Consistent tape type, width, and tension: some practitioners use a pre-tensioned
tape to standardise
• Accurate and consistent marking of the starting and subsequent measurement
points throughout the limb: for example, marking the starting point as a consistent
distance from the base of the nail bed of the middle finger
• Standardisation of the measurement as below and above the marked point
• Consistent number of measurement points used
• Measurements by the same operator at the same time each day
Table 5: Using two outcome parameters to calculate changes in limb volume after
treatment in Patient A
Parameter 1:
Parameter 2
Pre-treatment excess volume: 2,519 ml
Pre-treatment absolute volume of the
affected leg: 11,569 ml
Post treatment excess volume: 1,222 ml
Post-treatment absolute volume of the
Change in excess volume:
affected leg: 10,260 ml
2,519 – 1,222 = 1,297 ml
% change in excess volume:
1,297 x 100 = 52%
2,519
Change in absolute volume of the affected
leg:
11,596 – 10,260 = 1,336 ml
% change in absolute volume:
1,336 x 100 = 15.5%
11,596
cone) must be used consistently and are not interchangeable5,7. The hand or foot is not included in the calculation
of limb volume, although approaches to measuring the
hand have been explored9.
WATER DISPLACEMENT METHOD
This method is often viewed as the gold standard2 and is
mainly used in research. It relies on measuring the amount
of water that is displaced from a container when the limb
or part of the limb is submerged. This provides information on the volume of the whole limb, including the hand
or foot, and can be used to accurately measure the hand or
foot alone7. The total volume of each limb can be used to
calculate the excess and percentage excess volume of the
whole limb, hand, or foot. This is generally not practical
for clinical use.
Circumferential measurements have been shown to
correlate well with water displacement3,5,10,11, although
the reported volumes from water displacement are often
slightly lower than those from the circumferential measurements4. Therefore, the methods are not interchangeable.
30
PEROMETER METHOD (OPTOELECTRONIC
PLETHYSMOGRAPHY)
This device uses infra-red sensors to measure the limb7,
12. The limb is placed within a frame that does not touch
the limb but is moved along the length of the limb. The
method has some disadvantages, as it is expensive, is only
suitable for the clinical setting, and relies on the patient
being able to hold the limb steady in a specific position:
for example, the arm is generally abducted. The machine
provides various readings, including limb volume, and
5
produces a visual representation of the limb, which may
be particularly useful for patient education.
Tan et al.13 examined the agreement between a vertically
orientated perometer and the tape measure method in volunteer legs. He concluded that the methods were reliable
but not interchangeable, as the tape measure overestimated
the limb volume in comparison to the Perometer.
CALCULATIONS OF LIMB VOLUME
Details of limb volume, excess limb volume, and percentage excess volume of the limb, as well as sections of the
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2015 vol 15 no 1
Science, Practice and Education
Table 6: Use of Parameter 2 to calculate the percentage change in absolute limb volume
Example 1:
Example 2:
Limb volume before treatment: 10,000 ml
Limb volume before treatment: 16,000 ml
Limb volume after treatment: 8,000 ml
Limb volume after treatment: 14,000 ml
Reduction in limb volume: 2,000 ml
Reduction in limb volume: 2,000 ml
Expressed as a percentage of the starting Expressed as a percentage of the starting
treatment volume:
treatment volume:
2,000 x 100 = 12.5%
2,000 x 100 = 20%
10,000
16,000
Table 7: Measuring limb volume change in nine patients with unilateral lymphoedema
during a 12-day course of lymphoedema bandaging
Parameter 1: Change in excess limb volume
ID1
ID2
ID3
ID4
ID5
ID6
ID7
ID8
ID9
Mean
Excess
volume
(ml) at
Day 1 (pretreatment)
Excess
volume
(ml) at Day
12 (posttreatment)
Change
in
excess
volume
(ml)
%
change
in
excess
volume
1,788
1,789
3,501
1,446
1,708
3,485
4,182
4,760
5,650
3,145
1,045
968
2,581
1,107
471
2,536
3,736
2,295
4,944
2,187
-743
-821
-920
-339
-1,237
-949
-446
-2,465
-706
-958
-42
-46
-26
-23
-72
-27
-11
-52
-12
-35
Parameter 2: Change in absolute volume of the
affected limb
Before
After
Change %
treatments:
treatments in limb
change
affected
: affected
volume in limb
limb volume limb
(ml)
volume
(ml)
volume
(ml)
8,709
11,995
11,021
10,396
8,631
9,135
13,376
13,399
17,039
11,522
7,966
11,174
10,101
10,057
7,394
8,483
12,966
10,931
16,222
10,588
limb such as the distal and proximal segments, can be
calculated (Tables 1 and 3). Practitioners must understand
the implications of any data which are obtained through
software packages or calculators. This ensures that (1)
circumferential measurements are taken at the correct intervals with a precise starting point, (2) data are correctly
entered, and (3) any feedback that is given to patients or
recorded for the clinic or research purposes is accurate.
The formula for a cylinder requires the first circumferential measurement to be taken at 2 cm above the wrists or
ankle (midpoint of the cylinder). The frustrum formula
requires measurements at the end of each segment, so the
first circumference is taken directly at the wrist or ankle.
ESTABLISHING THE CHANGE IN LIMB VOLUME
AFTER TREATMENT
In a patient with unilateral lymphoedema, reporting
excess volumes before and after treatments also enables
a calculation of absolute and percentage change in excess
limb volume in relation to the pre-treatment excess volume (Table 5). This is the most accurate representation
EWMA Journal 2015 vol 15 no 1
-743
-821
-920
-339
-1,237
-652
-410
-2,468
-817
-934
-9
-7
-8
-3
-14
-7
-3
-18
-5
-8
of the actual change in the amount of lymphoedema in
the affected limb and is particularly useful for research
and audit purposes.
When a patient has bilateral lymphoedema, the excess
volume cannot be calculated. Instead, the reduction in
absolute limb volume may be expressed as a percentage
of the pre-treatment
7 total limb volume in each affected
limb. However, this does not provide precise details of the
lymphoedema volume or change in the lymphoedematous
component of the limb. As shown in Table 5, two outcome
parameters were used to calculate the changes in the affected limb of a patient with unilateral lymphoedema. The
two methods produced very different results. Although Parameter 1 relied on the unaffected leg as a control, the result from Parameter8 2 was influenced by the initial volume
of the limb.This is further illustrated in the examples given
in Table 6 where two limbs have each reduced by 2000mls,
although the calculation of percentage change, based on
the initial limb volumes of 10,000mls and 16,000mls, are
very different. Importantly, it is impossible to know how
much of an initial limb volume is due to lymphoedema
in a patient with bilateral swelling. 
31
APPLICATION IN AN AUDIT
Nine patients with unilateral lower limb lymphoedema
participated in an audit of a bandaging system incorporating the spiral application of a foam roll and the figureof-eight application of cohesive, short-stretch bandages14.
The patients were bandaged over 12 days with a total of
6 applications of the bandaging system (Fig. 1). The limb
volume was calculated using the formula for a cylinder
before and after the 12-day treatment course. Circumferential measurements were taken at 4-cm intervals along
the affected and unaffected limb, starting 2 cm above the
ankle. These data were entered into a spreadsheet to calculate the limb volume, excess volume, and % excess volume.
The changes in limb volume in the 9 patients (Table 7)
were expressed using two parameters.
n
Parameter 1: percentage change in excess limb
volume over time.
n Parameter 2: percentage change in absolute limb
volume over time.
RESULTS
The results from the 9 patients with unilateral lymphoedema show a mean reduction in the excess limb volume of
35% (range 11–72%) when Parameter 1 was used (Table
7). This was similar to the mean reduction of excess volume of 33.5%, which was reported by Badger et al.15 in
a study of 31 patients after 18 days of bandaging. Using
Parameter 2, the mean reduction in the absolute limb
volume in the 9 patients who took part in the audit was
8% (Table 7).
CONCLUSIONS
The two parameters for calculating the change in limb
volume yielded different results and were not interchangeable. Our results suggest that Parameter 1 is only suitable
for patients with unilateral lymphoedema, but provides
information on the reduction in lymphoedema volume.
Parameter 2 may be used for patients with bilateral lymphoedema, where no comparator (unaffected) limb is
available.
Both parameters should be reported in research, and
both limbs should be measured. However, Parameter 2
should be used with caution, as the percentage reduction
is based on the whole limb volume. The accurate representation of limb volume reduction cannot be achieved
using Parameter 2, where the extent of lymphoedema is
unknown, as a comparison with the unaffected limb is
not possible. However, both parameters are useful in the
clinical setting to monitor changes in the limb volume
over time.
To ensure accuracy, practitioners should use standardised, valid, and reliable approaches when assessing limb
volume change. Limb volume measurements should be
used in conjunction with other quality of life measures
and patient-reported outcomes to provide a more holistic
perspective on progress and change. Future work could
involve the use of a larger dataset to examine the correlations between different approaches to quantifying limb
volume reduction.
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