Use of  the doppler in the community is a vital tool of assessment when trying to  determine the underlying aetiology of  leg ulcers and decide on a course of treatment which will maximize wound healing potential. Predominantly leg ulceration is of venous origin  (approximately 75 % )  but before any kind of  compression management can be  considered, a doppler test needs to be performed to determine whether there is arterial involvement or indeed whether the ulcer is the direct cause of  arterial compromise.

When a doppler assessment is necessary in the community it is important that it is planned  ahead of time to  prevent problems occurring. The patient / patient's carer needs to be informed of the approximate visiting time in order to be prepared.  Due to the nature of the test i.e. compressing an ulcerated area during cuff inflation, it may be appropriate to suggest taking an oral analgesic or anti-inflammatory medication (whatever has been prescribed by the GP) about an hour prior to the agreed visiting time. It is also necessary to inform the patient that they will be required to lie down (preferably flat as possible without compromising breathing) for approximately one hour in total, so consideration needs to be given as to the time of visit; for example, it is inappropriate to expect patient compliance when they have just taken diuretic medication.

On arrival it is important to ascertain how long they have been resting  before  commencing the procedure and to answer any questions they might have. Patients who have not had this procedure done before might be worried and apprehensive and may need reassurance and an explanation. Even patients who have had this procedure done before may have found the experience uncomfortable or painful and will need support and encouragement and an explanation of how important the test is to the management of their wound.

Recording Ankle Brachial Pressure Index (ABPI)  also known as Resting Pressure Index (RPI) Community nurses performing this procedure should have had the appropriate training and supervised practice . Checks should be made that the patient has rested for the appropriate amount of time (15-20 minutes). If this has not been achieved, time taken to explain the procedure, set out and  check the equipment ,  reduce the existing dressings , and  prepare the patient's arms and legs for access  will enable the necessary amount of time to have elapsed prior to commencing. The brachial pressure is at first measured in both arms using the doppler. The doppler probe should be held at a 45 degree angle to the limb and preferably in the direction of the blood flow. the electrode gel assists the transmission of the pulse to the probe. It is therefore not necessary to apply excessive pressure on  the limb using the probe. Next is to identify the sound of the arterial flow. The artery has a high pitched pulse form. If the sound you hear is a gale-like whoosh with ill-defined beats you are listening to venous return and need to  change the probe position . These should be repeated (two consecutive  measurements at each arm) and the highest of these readings recorded. For the purpose of this test,  systolic pressure only is required. To measure the ankle pressure the correct position of the cuff should be located approximately 5cm above the malleoli. Any wounds which have had their dressings removed need to be covered by a sterile shield to prevent contamination of the wound bed and also to prevent cross contamination of the cuff. Prior to inflating the cuff, the pedal pulses have to be located using the doppler. There are four main pulses to identify and listen for (see diagram). It is quite common in arterial compromise to find foot pulses absent or  diminished. Although  approximately 75% of legs ulcers are venous in origin it is thought many of these patients will have co-existing arterial disease. The posterior tibial pulse is more reliable than the dorsalis pedis (see diagram) which is congenitally absent in 10% of people:  in a further 10% the dorsalis pedis is impalpable. The systolic measurements should be taken twice on each ankle using  different pulse points for greater accuracy. When all the measurements have been taken and recorded the Ankle Brachial Pressure Index can be calculated using the highest systolic doppler recordings. Note ABPI isn't reliable in patients with diabetes due to arterial calcification which can lead to falsely  high ABPI's. 

These two Doppler samples above have kindly been provided by...

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