Venous leg ulcer clinic standard operating procedure for assessment of ankle brachial pressure index (ABPI)

The following standard operating procedure (SOP) is intended as an outline for Health Boards to develop their own standard operating procedure. The example below has been adapted from procedures used by the clinical team at NHS Tayside. It may need to be adjusted or expanded depending on availability of facilities (e.g. photography) and services locally and to ensure links are established with relevant local services (e.g. Primary Care, District Nursing, Vascular Surgery, Dermatology).

Purpose/background

Lack of appropriate clinical assessment of patients with limb ulceration in the community has often led to long periods of ineffective treatment (RCN, 2024). The role of Doppler ultrasound in detecting arterial insufficiency is considered an essential part of the assessment process for chronic leg ulcer management (NICE 2024). It should be used in conjunction with the medical history, physical assessment and clinical presentation of the ulcer. The aim of this SOP is to ensure safe and standardised care of venous leg ulcers in the Community Venous Leg Ulcer Clinic.

Scope

This SOP applies to all registered nurses working within the Community Venous Leg Ulcer Clinic.

Responsibility

All trained nurses are responsible for reading this SOP and signing to say they have understood this SOP and will comply with the instructions within.

Procedure

It is the individual staff member’s responsibility to ensure they work within their level of competence. This procedure should only be carried out by staff who are trained and competent to do so.

Introduce all staff to the patient. Confirm the patients name and date of birth. Explain to the patient what they can expect from the assessment. Do not perform Doppler ultrasound if suspicion of DVT as it will be painful and may dislodge the clot.
Rest patient for at least 15 minutes before commencing the procedure. Patient should lie flat. However if patient has problems with this due to breathing or arthritis lie the patient as flat as is comfortably tolerated and document this in the patients record.
Place the blood pressure cuff around the patient’s arm (the cuff should be the correct size for the limb)

Indication	Width (cm)	Length (cm)	Limb circumference (cm)
Small adult/child	10-12	18-24	<23
Standard adult	12-13	23-35	<33
Large adult	12-16	35-40	<50
Adult thigh cuff	20	42	<53

British Hypertension Society (2006)

Locate the brachial artery and apply a pea sized amount of ultrasound gel over it.
Switch on Doppler. Hold probe at 45-60 degree angle to the blood vessel and direct it into the blood flow. If no sound is heard, try adjusting the angle of the probe. Do not press the probe down into the patient as this is uncomfortable and can compress the vessel.
Inflate the cuff while holding the probe over the pulse until any sound disappears. Slowly deflate the cuff and when the sound reappears this indicates systolic pressure. Document this figure.
Repeat the procedure for the other arm.
Cover ulcer with cling film and apply the blood pressure cuff just above the malleoli to cover the gaiter area.
Locate one foot pulse (the posterior tibial, peroneal, anterior tibial or dorsal pedial pulse can be used)
Apply ultrasound gel and position the probe at a 45-60 degree angle in the direction of the blood flow as previously described.
Inflate the cuff while holding the probe over the pulse until any sound disappears. Slowly deflate the cuff and when the sound reappears this indicates systolic pressure. Document this figure.
Locate a second foot pulse and repeat the procedure
Repeat for the other limb.
To calculate the left ABPI: Divide the highest of the two ankle readings for the left leg by the higher of the two brachial pressures.
To calculate the right ABPI: Divide the highest of the two ankle readings for the right leg by the higher of the two brachial pressures.
Interpret the ABPI within the context of a full medical history, physical assessment and clinical presentation of the ulcer.
Patients should have another Doppler assessment at 12 weeks if there are signs of delayed healing or poor healing. Then as indicated at 3-monthly intervals until the ulcer is healed. If there is no progress/improvement the patient should be referred to the specialist leg ulcer clinic (see criteria for referral to secondary care below).

Criteria for referral to secondary care

Suspicion of malignancy
Peripheral arterial disease (ABPI <0.8 or >1.3)
Vasculitis
Atypical distribution of ulcers
Suspected contact dermatitis or dermatitis resistant to topical steroids
Non-healing ulcer despite appropriate treatment at 12 week review