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 TrustThanks to Dr Jon Evans

Vascular Business Unit Manager Huntleigh Healthcare

Ellie Lindsay Leg Club Foundation

Aims of this session

• Practical hints and tips when performing Doppler assessment

• Calculating ABPI

• Alternatives to Doppler• Understanding compression therapy

what about “leg ulcers”?

Examination of the arterial patient

Past Medical History• Cardiac: angina; arrhythmias; MI

• Diabetes

• Hypertension• Renal• Neurological: cerebrovascular; peripheral

• Injuries

• Arthritis / collagen disease• Clotting abnormalities

Clinical features of the ischaemic foot

• Cold

• Pale colour

• Glass like skin

• Little callous

• Pulse less

• Dependent rubor

• Claudication

• Rest pain

• Ulcers on edges© copyright Cardiff and Vale Trust

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

• 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 compressrefer to specialist

Do not compress - refer urgently to vascular

specialist.

Formula to Calculate ABPI

Highest Ankle pressureAT/PT/DP for that leg=___________Highest Brachial pressure whether it is left or r ight.

Doppler signal quality

• Tri-phasic

• Bi-phasic

• Mono-phasic

Other useful tests

• Wave form assessment• Exercise Doppler• Segmental pressures• Buergers test• Slow capillary return after blanching• Pole test

Pole Test

Waveform analysis

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

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

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

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

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

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)

The New Dopplex Ability

Specially designed two chamber cuffs are used to detect systolic pressures

Two Chamber Cuffs

• 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

• Improve venous return • Promote a healthy wound environment

Improve condition of skin/patient comfort • Reduce oedema • Control exudate and odour Reduce pain

Registered Charity 1111259

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 healfor the first time

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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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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:

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 lawP ∝ T/R

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radius

pressure

graduated compression:higher pressure at the ankle, with decreasing pressure exhibited atthe calf

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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 30mmHg3c: high compression – up to 40mmHg3d: very high compression – up to 50mmHg

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Bandage Classif ication

Thomas 1990Class 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)

Registered Charity 1111259

Registered Charity 1111259

Registered Charity 1111259

Registered Charity 1111259

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

Finally

• Before diving in make sure you have assessed the risks.

• Thank you for your attention