Doppler and compression british dermatology conference london 7th july 2011
1. Latest Technology in practical ABPI
Assessments understanding
compression
Elaine Gibson BSc(Hons) DipN, RGN
Medical Affairs UKI ConvaTec
Tissue Viability Nurse Specialist
East Kent University Hospitals Foundation
Trust
Thanks to Dr Jon Evans
Vascular Business Unit Manager Huntleigh
Healthcare
Ellie Lindsay Leg Club Foundation
2. Aims of this session
• Practical hints and tips when performing
Doppler assessment
• Calculating ABPI
• Alternatives to Doppler
• Understanding compression therapy
6. Doppler Assessment
•Doppler probes come in several Frequencies 2-10 MHz
•It is important to use contact gel, use at 45 degree angle
•8MHz probe is ideal for measuring ABPI
7. • Position patient supine and rest for
15-20 minutes
• Measure both Brachial pressures
• Measure two pedal pressures per
foot
• Calculate ABPI using highest
ankle/highest brachial pressure
Doppler ABPI Measurements
ABPI > 1.0 - 1.3
ABPI = 0.8 - 1.0
ABPI = 0.5 - 0.8
ABPI < 0.5
ABPI > 1.3
Unlikely to be arterial
in origin
Mild peripheral
disease
Moderate arterial
disease
Severe arterial
disease
Measure toe pressures
or refer to specialist
Apply compression
therapy
Apply compression
therapy with caution
Do not compress
refer to specialist
Do not compress - refer
urgently to vascular
specialist.
8. Formula to Calculate ABPI
Highest Ankle
pressure
AT/PT/DP for
that leg
=___________
Highest
Brachial
pressure
whether it is
left or right.
10. Other useful tests
• Wave form assessment
• Exercise Doppler
• Segmental pressures
• Buergers test
• Slow capillary return after blanching
• Pole test
Pole Test
Waveform analysis
11. Pole Test
• Pole test for
measurement of ankle
pressures in patients
with calcified vessels:
the Doppler probe is
placed over a patent
pedal artery and the foot
raised against a pole that
is calibrated in mm Hg.
The point at which the
pedal signal disappears
is taken as the ankle
pressure
12. Other useful tests
Toe pressures: Doppler or photoplethysmography
• Toe/brachial pressure>0.6 = normal
• Rest pain usually present in patients with index < 0.15
• Absolute pressure in the toes of 20-30mmHg is
usually associated with rest pain
13. Inflate cuff to 60mmHg
Hold for 10 secs
Inflate by 10mmHg
Up to 100mmHg Then
inflate by 20 mmHg
When the signal disappears
take the reading below
If present at 180mmHg
record this as the reading
How to use Pulse Oximetry
14. Place sensor on one of the 1st
- 3rd
toes
Place the cuff near the ankle
Repeat arm procedure
Calculate index:
toe pressure
finger pressure
Place sensor on toes, listen for signal
in horizontal position
If signal lost further assessment is
required
Pulse Oximetry
15. Pulse Oximetry Limitations
• Light reflection can be
affected by hyper
calcified nails
• Patients wearing nail
varnish
• Patients suffering from
chronic obstructive
airways disease
• Can be affected with
macro-vessel disease in
diabetic patients
16. Problems with measuring ABPI using Doppler
• Difficult to maintain vessel contact during inflation and
deflation
• A reasonable knowledge of anatomy is required
• Difficult to locate vessels
• Typical average time for ABPI is 11mins + 15-20 mins rest
(Ipsilon and Get ABI Study 2006)
• Clinicians must be trained and monitored
(RCN Guidelines 2006)
• Doppler ABPIs taken by junior doctors disagreed with
vascular technicians by 30%. This improved to 15% after
formal training
(Ray et al 1994)
18. Specially designed two chamber cuffs are used to detect systolic
pressures
Two Chamber Cuffs
19. • Extremely easy to use and fully automatic
• Rapid bi-lateral ABI measurement in < 5mins
(Doppler based ABI typically takes 30mins)
• No need to rest patient for 15mins
• ABI can now be undertaken by less skilled staff
• Only have to apply 4 cuffs
• Physiologically more accurate
• No need to remove socks and tights
• Integral printer for documentation of results and
waveforms
• Automatic interpretation
• Clinically validated (Lewis et al, 2010)
Advantages of Auto ABI
20. • Improve venous return
• Promote a healthy wound environment
Improve condition of skin/patient comfort
• Reduce oedema
• Control exudate and odour Reduce pain
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21. researchers at Charing Cross
hospital in the late 80s
demonstrated that venous leg
ulcers could be encouraged to
heal by the use of four-
component pressure
bandaging;
even chronic ulcers of many
years duration would heal
for the first time
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22. compression in venous insufficiency
leads to an increase in forward flow
and thus to an improvement in venous
pump output;
this effect has more to do with
hydraulic principles than with the fact
that the valves become sufficient
again
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23. structure & properties of the bandage
size & shape of the leg
skill & technique of the bandager
functional activities
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compression is determined by complex interactions
between:
24. the applied pressure (P) is
directly proportional ( ) to
the tension (T) in a bandage
but inversely proportional
to the radius of curvature (R)
of the limb to which it is applied
∝
P is
proportional
to T/R
Laplace’s law
P ∝ T/R
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26. BS 7505: 1995
Type 1 : Conforming and Retention
Type 2: Light Support
Type 3: Compression
3a: light compression - up to 20mmHg
3b: medium compression – up to 30mmHg
3c: high compression – up to 40mmHg
3d: very high compression – up to 50mmHg
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Bandage Classification
27. Thomas 1990
Class 3a – Light compression
(14 - 17mmHg)
Class 3b – Moderate compression
(18 -24mmHg)
Class 3c – High compression
(25 – 35mmHg)
Class 3d – Extra high compression
(up to 60mmHg)
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31. Key points
• The majority of leg ulcers are venous in origin
• Compression therapy is the treatment of choice
• Choice of compression systems enhances
concordance
• No ulcer will heal without a good blood supply
• Other conditions are rare but need to be
considered.
• Ensure you have time to get an good history with
relevant investigations to support your diagnosis
• If in doubt document and refer to
multidisciplinary team
32. Finally
• Before diving in
make sure you have
assessed the risks.
• Thank you for your
attention
