The test provides your doctor with important information about the flow of blood through your major arteries and veins. It can also reveal blocked or reduced blood flow through narrowed areas in the arteries, which could eventually lead to a stroke. Learn more: Ultrasound ». Your doctor may suggest a Doppler ultrasound exam if you show signs of decreased blood flow in the arteries or veins of your legs, arms, or neck.
A reduced amount of blood flow may be due to a blockage in the artery, a blood clot inside a blood vessel, or an injury to a blood vessel. A Doppler ultrasound can help determine the blood pressure within your arteries. It can also show how much blood is currently flowing through your arteries and veins. Smoking causes your blood vessels to narrow, which can affect the results of your test.
There are no risks associated with this test, and most people feel little to no discomfort during the procedure. The procedure can vary slightly, but in general, you can expect the following:. When examining your leg arteries and veins, your doctor will look for narrowing of the blood vessels. This condition may cause skin discoloration , pain when you walk or rest, and ulcers on the foot or ankle. Read more: Ankle ulcers ». The test will be completed in about an hour. Depending on your signs and symptoms, you may be asked to perform some mild exercises after the procedure.
In general, there are no special instructions following a Doppler ultrasound. You may resume your usual activities right away, unless your doctor tells you otherwise. Normal test results indicate that you have no narrowing or blockages in your arteries.
It also means that the blood pressure in your arteries is normal. Abnormal blood flow patterns, including narrowing or closing of the arteries, can indicate:. If the patient is unable to lie flat raise their legs to the level of the heart or consider whether a duplex scan in secondary care would be more appropriate. Next, gather a Doppler ultrasound machine with 8Mhz probe; sphygmomanometer and the appropriate sized blood pressure cuff; cling film to cover any active ulcers to prevent contamination of the cuff and for comfort; and some ultrasound gel.
Apply the blood pressure cuff to the patient's arm above the elbow. Locate the brachial artery with by palpating with your fingers and then apply the ultrasound gel to this area. Apply the Doppler probe to the gel at about degrees and find the area that provides the clearest audible pulsatile sound. If you find it difficult to make the sounds, use Doppler headphones.
Inflate the blood pressure cuff until the pulsatile sounds diminishes, then 'slowly' release the cuff and note when the pulsatile sounds returns. Document this as the brachial systolic pressure and repeat this procedure on the other arm.
You will use the higher of the two values when you calculate the ankle brachial pressure index ABPI measurement. If the patient has active ulceration, apply cling film to these areas. Locate the pulses in the foot using the Doppler probe and ultrasound gel.
It is good practice to use two of these pulses for each foot. Apply the blood pressure cuff to the patient's ankle just above the malleoli. Place the Doppler probe on the pulse to be used and locate the clearest audible pulsatile sound again. Inflate the blood pressure cuff until the pulsatile sounds disappears. Slowly deflate the cuff and wait until the pulsatile sound reappears. Note this value down. Repeat this step on another foot pulse.
Note that if, when inflating the blood pressure cuff, that the artery cannot be compressed i. The discussions surrounding the purpose of the Doppler assessment in this article is based on those patients 'without' active ulceration, so the Doppler's role in these assessments will be to assess whether peripheral vascular disease is present to determine the patient's suitability for compression therapy as a treatment.
Again, it is important to be mindful that there is no definitive cure for venous disease and it is about managing symptoms appropriately. Prepare the patient fully and ensure it is an appropriate test for their circumstances. For instance, if the patient is experiencing pain from a chronic condition, it is unlikely they will tolerate cuff inflation or remain still for the required length of time, so consider the need for analgesia.
The same applies to patients who will not be able to lie flat so it is advisable to raise their legs to the level of the heart. These issues should be acknowledged at the holistic assessment stag; if they are ignored, we may experience inaccurate results which could instigate inappropriate treatment.
The clinician may also experience difficulty in people who have larger limbs or limbs that are heavily oedematous and clinicians should consider bigger blood pressure cuff size; lower frequency Doppler ultrasound probes; and duplex scanning in secondary care.
This procedure is the traditional method of Doppler assessment but 'automated' ABPI systems ArjoHuntleigh, Dopplex Ability are available now that will be of particular use to primary care nurses who are concerned about consultations times in busy practice settings.
The benefits of this system are that ABPI can be calculated in three minutes; ABPI measurement are automatically calculated with print out labels; and the patient does not need to rest before using these machines for ABPI measurement. Preventing active ulceration This article has provided an overview of managing venous disease and has outlined the role of the Doppler assessment and its advancements to determine the vascular status.
If patients are left untreated, it is likely they will develop more severe symptoms of venous disease in future which are harder to treat and likely to have a greater negative impact on the patient's quality of life. Early identification of venous disease through assessment, implementing preventive strategies and regular reviews can prevent active ulceration. Always use a calculator to avoid mistakes.
Communication Always seek assistance from the tissue viability or dermatology services if you are unsure of the best treatment for your patients or need clinical advice. A higher frequency probe 5 or 8MHz will be suitable for listening to superficial objects such as blood vessels. The transmitted sound wave reflected from moving red blood cells is detected by the receiver and the difference between the frequency of the transmitted sound wave and the frequency of the received signal is known as the Doppler shift.
This Doppler shift is typically in the audio range and is converted into the sound heard from the Doppler unit. Ankle brachial pressure index ABPI A handheld portable Doppler ultrasound machine is used as a non-invasive method to assess the blood flow in the main arteries of the lower leg carried out using a strict protocol.
The ABPI for each leg is calculated by dividing the higher of the ankle pressures by the higher of the twobrachial pressures. The readings should be roughly the same but if the result indicates pressure variation then further investigations may be necessary see below. The Doppler assessment should not be viewed as an indicator of, nor does it diagnose, venous disease in the lower leg; however, it will assist and guide management in cases of peripheral arterial disease.
ABPI measurement is an important element in defining a safe level of compression therapy for those patients with venous disease; therefore, it is essential that community nurses perform Doppler ultrasound as an integral part of their assessment.
Some Doppler ultrasound machines also provide a visual wave form. Measuring ankle systolic pressure Select an appropriately sized sphygmomanometer cuff, protect fragile skin and the wound. Cover the ulcer with cling film toprevent cross infection and place around the leg just above the ankle and with the tubing away from the gel.
Palpate the posterior tibial artery, apply ultrasound gel and locate the best signal. Inflate the sphygmomanometer cuff until the signal disappears, then deflate the cuff slowly and record the pressure at which the signal returns.
Repeat this procedure with either the anterior tibial or peroneal artery. Repeat for the other leg. Use the highest of these two readings to calculate the ABPI. Vasoconstriction may occur if the patient is uncomfortable, too hot or too cold or anxious, making the sound difficult to hear.
An ABPI of. Conclusion While Doppler ABPI remains an important part of the assessment process it is only a part of the overall holistic assessment of the patient with leg ulceration and should not be used in isolation or as a sole diagnostic tool. Practitioners must be taught how to use the Doppler ultrasound machine competently, remain competent, be able to interpret and document the results correctly, and have the confidence to refer patients to appropriate services in a timely manner.
References 1. Franks P, Moffatt C. Leg ulcers. Clinical practice guidelines: The nursing management of patients with venous leg ulcers. London: RCN; Moffatt C, Franks P. Implementation of a leg ulcer strategy. Br J Dermatol ; Assessment, prevention andmonitoring of chronic leg ulcers in the community: report of a survey.
J Clin Nurs ;2 5 Bell M.
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