1. Lucy Stopher A/CNS Vascular Surgery
DOPPLER ASSESSMENT AND
ANKLE BRACHIAL INDEX (ABI)
Lucy Stopher
A/CNS Vascular Surgery

2. Objectives How to assess pedal pulses Different doppler sounds
What is an ABI
How to perform an ABI
Interpretation of results
When is it required
Why is an ABI so important

3. PEDAL PULSES

4. PALPATING PEDAL PULSES
Dorsalis Pedis: To palpate pulse, place fingers just lateral to the extensor tendon of the great toe. If you cannot feel a pulse, move fingers more laterally
Posterior Tibial: To palpate pulse, place fingers behind and slightly below the medial malleolus of the ankle. In an obese or edematous ankle, the pulse may be more difficult to feel

5. PALPATING PEDAL PULSES

6. TECHNIQUE TO DOPPLER USE
If possible palpate the pulse first
Place the doppler at a ̊angle over the skin
Once you hear a signal manipulate the doppler to try and achieve the best sound

8. DOPPLER SIGNALS TRIPHASIC:
This is represented by three sounds heard very quickly together (duh...duh...dum), as the blood runs through a healthy un-diseased artery.

9. DOPPLER SIGNALS

10. DOPPLER SIGNALS BIPHASIC:
This can be recognised as two sounds heard together (duh, dum ... duh, dum), this may be because the Doppler probe is not at the optimum angle. Again, it indicates a healthy artery.

11. DOPPLER SIGNALS MONOPHASIC:
A single, almost ‘banging’ sound (...dum! ...) indicates that the Doppler signal is unable to penetrate a diseased artery.

12. DOPPLER SIGNALS
VENOUS:
A wooshing sound with no discernible beat.

13. PEDAL PULSES: DOCUMENTATION
Colour: Pale, pink, red, mottled
Warmth: Cool, cold, warm, hot
Movement: Full, limited, none
Sensation: Do they have neuropathy? Is this normal for them?
Pulses: Palpable or on doppler?

14. WHAT IS AN ABI? ABI stands for ankle brachial index
It is the ratio of the systolic ankle pressure to the systolic arm pressure.
The systolic pressure of the leg decreases in proportion with the degree of occlusion
It indicates the amount of arterial supply reaching the ankle

16. HOW TO PERFORM AN ABI?
Lie the patient down as flat as possible for 20 minutes. This allows the leg muscles to relax and equalises the blood pressure.
Assess the systolic blood pressure in each limb with the doppler.
Document each systolic blood pressure on the ABI chart or the inpatient notes.

17. HOW TO PERFORM AN ABI?
Choose the higher systolic arm pressure and use that to calculate the result for both legs.
Choose the higher ankle pressure and divide by the arm pressure and repeat for the other leg
ABI = Higher Ankle Pressure
Higher Arm Pressure

19. HOW TO INTERPRET THE RESULT
>1.2 Indicates calcification of the vessels and so the test is inaccurate – perform toe pressures as the toe vessels do not calcify.
Normal, compression therapy can be applied as per medical team.
Arterial disease causing claudication
Arterial disease causing rest pain
<0.3 Arterial disease causing gangrene/ non healing wounds

20. WHEN IS AN ABI REQUIRED
Anytime the arterial supply of the legs are in question e.g. non healing foot wounds with no palpable pulse
For the diagnosis/management of leg ulcers
If a patient has venous insufficiency an ABI is required prior to the application of compression.
On admission for ALL vascular patients with a lower limb problem (e.g. not if the patient is having a carotid endarterectomy)
For ALL patients post angioplasty +/- stent and post bypass graft/endarterctomy

21. WHY IS AN ABI SO IMPORTANT?
It gives an indication of the lower limb arterial blood supply, without needing to wait for costly scans.
It gives an indication of the effectiveness of a procedure such as angioplasty or bypass
When the surgeon follows up a patient they can compare the previous ABI to the patients current ABI to assess deterioration

22. SUMMARY
If a patient has a leg or foot wound and you cannot palpate pedal pulses you should perform:
Doppler Assessment
Ankle brachial index (ABI)
An ABI is a cost effective and saves the necessity to wait for scans
ABI’s are essential prior to application of compression bandaging