Procedure: ABPI

Question 1

How do you explain to a patient what ankle-brachial pressure index is?

Answer 1

A test that compares the blood pressure in your legs to the blood pressure in your arms, to help diagnose peripheral arterial disease

Question 2

Which 2 questions should you ask the patient before starting the ABPI procedure?

Answer 2

Do you have diabetes?

Are you in any pain?

Question 3

What position should the patient ideally be in for the ABPI procedure, and why?

Answer 3

Lying on bed completely flat, so that the brachial pulse is at heart level and won’t be artificially influenced by hydrostatic pressure or gravity

Can be lying at 45 degrees but should put pillow under arm so that the brachial pulse is still at heart level, to reduce influence of gravity

Question 4

What are the contraindications for having an ABPI?

Answer 4

Suspected DVT or superficial thrombophlebitis: Doppler probe could be painful or dislodge the clot

Severe leg pain

Cellulitis

Recent surgery, ulcers, casts, bandages that can’t be compressed

Question 5

When measuring brachial blood pressure for ABPI, what should you apply first?

Answer 5

Put blood pressure cuff on patient’s arm with tubing facing towards probe

Inflate cuff slightly to make sure you which way to turn dial, warn patient that you are going to check that cuff is working

Question 6

In ABPI, after putting on the blood pressure cuff how do you locate the brachial pulse?

Answer 6

Palpate the brachial pulse with fingers (don’t need to use stethoscope) to estimate where to use Doppler probe

Question 7

In ABPI, after palpating the brachial pulse what should you do, and why?

Answer 7

Apply ultrasound gel over where the brachial pulse was palpated

Ultrasound gel is designed to minimise air bubbles between skin and the Doppler probe, so sound waves will travel better

Question 8

What Doppler probe frequency is used for ABPI?

Answer 8

8Hz

Question 9

In ABPI, how do you locate the brachial pulse with the Doppler probe?

Answer 9

1. Turn on probe
2. Slowly move from side to side over the ultrasound gel until you hear waveform
3. Hold probe at 45 to 60 degrees to skin to obtain clearest waveform signal

Question 10

In ABPI, how do you measure the brachial pulse after locating the clearest waveform with the Doppler probe?

Answer 10

1. Warn patient that you are going to inflate cuff and it will feel tight
2. Inflate blood pressure cuff 20-30mmHg above when waveform is no longer audible
3. Slowly deflate cuff to see when waveform becomes audible again: This is the brachial blood pressure

Question 11

In ABPI, what 2 things should you do after measuring the brachial pulse?

Answer 11

1. Remove blood pressure cuff and wipe off ultrasound gel with tissue
2. Record brachial systolic pressure

Question 12

In ABPI, which arm do you use for the brachial systolic pressure?

Answer 12

Measure brachial systolic pressure in both arms and use the highest measurement to calculate both left and right ABPI

Question 13

In ABPI for a single ankle, how many blood pressures do you measure?

Answer 13

2: Dorsalis pedis and posterior tibial

Question 14

When measuring ankle blood pressure for ABPI, what should you apply first?

Answer 14

Put on blood pressure cuff with the tubes facing upwards (towards patient)

Inflate cuff slightly to make sure you which way to turn dial, warn patient that you are going to check that cuff is working

Question 15

In ABPI, what should you do after putting on the blood pressure cuff to locate the dorsalis pedis and posterior tibial pulses?

Answer 15

Palpate with fingers where pulse is strongest, to estimate where to place Doppler probe

Question 16

In ABPI, how do you locate the dorsalis pedis pulse with the Doppler probe?

Answer 16

1. Hold Doppler probe over where dorsalis pulse was palpated (usually over bony prominence)
2. Slowly move Doppler probe between 1st dorsal web space and navicular bone to find clearest waveform
3. Hold Doppler probe at 45 to 6o degrees and in direction of blood flow (up towards heart)

Question 17

After finding the dorsalis pedis waveform, how should you measure the dorsalis pedis systolic pressure?

Answer 17

1. Warn patient that you are going to inflate cuff and it will feel tight
2. Inflate blood pressure cuff 20-30mmHg above when waveform is no longer audible
3. Slowly deflate cuff to see when waveform becomes audible again: This is the blood pressure

Question 18

In ABPI, what 3 things should you do after measuring the dorsalis pedis systolic pressure?

Answer 18

1. Deflate blood pressure cuff and wipe off ultrasound gel
2. Record dorsalis pedis systolic pressure
3. Tell patient that you are now going to measure the posterior tibial systolic pressure

Question 19

In ABPI, how do you locate where the posterior tibial pulse is strongest?

Answer 19

Palpate with fingers behind medial malleolus and slightly above heel, to estimate where to put Doppler probe

Question 20

In ABPI, how do you locate the posterior tibial pulse with the Doppler probe?

Answer 20

1. Hold Doppler probe over where posterior tibial pulse was palpated (usually over bony prominence)
2. Slowly move Doppler probe between back of medial malleolus and heel to find clearest waveform
3. Hold Doppler probe at 45 to 6o degrees and in direction of blood flow (up towards heart)

Question 21

After finding the posterior tibial pulse waveform, how do you measure the systolic blood pressure?

Answer 21

1. Inflate cuff 20-30mmHg above when waveform disappears
2. Slowly deflate cuff to see when waveform reappears: This is the posterior tibial systolic pressure

Question 22

After measuring the posterior tibial systolic pressure, what 2 things should you do next?

Answer 22

1. Remove blood pressure cuff and wipe off ultrasound gel
2. Record posterior tibial systolic pressure

Question 23

How do you calculate the left ABPI?

Answer 23

Highest left ankle blood pressure (PT or DP)
—————————————————————
Highest brachial blood pressure (left or right arm)

Give ABPI to 2 dp

Question 24

How do you calculate the right ABPI?

Answer 24

Highest right ankle pressure (PT or DP)
———————————————————
Highest brachial pressure (left or right arm)

Give ABPI to 2 dp

Question 25

Which 3 further investigations should you do after ABPI procedure?

Answer 25

1. Peripheral vascular examination 2. Blood tests eg. HbA1c and serum cholesterol 3. Duplex ultrasound or CT angiogram

Question 26

What are the 6 categories of ABPI ratios?

Answer 26

More than 1.4: Medial wall calcification 1.0-1.4: Normal 0.91-0.99: Borderline normal, so peripheral arterial disease could be present 0.8-0.9: Mild arterial disease 0.8-0.5: Significant arterial disease Less than 0.5: Critical limb ischaemia

Question 27

What are the 3 steps of management for ABPI ratios greater than 1.4?

Answer 27

Suggests arterial calcification: Can be due to diabetes, RA, vasculitis, chronic renal failure 1. The ABPI is clinically inconclusive so refer patient to vascular specialist, and repeat ABPI every 3 months 2. Lifestyle changes 3. Generally incompressible but is still safe for high level compression therapy

Question 28

What are the 4 steps of management for ABPI ratios 1.4-1.0?

Answer 28

This is normal but doesn’t exclude peripheral arterial disease 1. Still do 3 main further investigations 2. Repeat ABPI every 12 months or sooner if patient develops ischaemic pain 3. Lifestyle changes 4. High level compression therapy

Question 29

What are the 3 steps of management for ABPI ratios 0.99-0.9?

Answer 29

1. Further 3 investigations 2. High level compression therapy 3. Lifestyle changes

Question 30

What are the 3 steps of management for ABPI ratios 0.9-0.8?

Answer 30

1. Further 3 investigations 2. Lifestyle changes 3. Reduced level compression therapy

Question 31

What are the 3 steps of management for ABPI ratios 0.5-0.8?

Answer 31

Severe arterial disease 1. DO NOT give compression therapy 2. Lifestyle changes 3. Further 3 investigations and referral to vascular specialist

Question 32

What are the steps of management for ABPI ratios less than 0.5?

Answer 32

Critical limb ischaemia 1. DO NOT give compression therapy 2. Urgent referral to vascular surgeon

Question 33

Which 4 lifestyle changes should you recommend, for peripheral arterial disease?

Answer 33

Exercise: Walk until pain becomes intolerable then rest, as this will improve IC, can also join supervised exercise class Smoking cessation Weight loss Healthy diet: Mediterranean diet eg. olive oil, whole grains, fruits and vegetables, nuts, fatty fish

Question 34

How should you proceed with ABPI if a patient has a leg ulcer?

Answer 34

Wrap clingfilm around leg ulcer, then measure ABPI

Question 35

What is the difference between high level and reduced level compression therapy, and when do you give each based on ABPI?

Answer 35

High level compression therapy: Over 40 mmHg, used when ABPI is over 0.9 Reduced level compression therapy: Less than 40 mmHg (usually 20-30), used when ABPI is 0.8-0.9

Question 36

What are the 4 main benefits of compression therapy?

Answer 36

Improved venous return to heart Reduces swelling/oedema in legs Wound healing due to improved circulation Pain relief

Question 37

Why is compression therapy not given if ABPI ratio is less than 0.8?

Answer 37

Compression therapy can restrict blood flow in the lower limbs, which can further restrict the already compromised blood supply Increases chance of gangrene, ulceration, ischaemia