Posts Tagged ‘ABI’

Ankle-Brachial Index? It’s Easier Than You Think

Wednesday, December 7th, 2016

Determining a patient’s ABI is a vital part of wound care, but unfortunately this step is often avoided … or even omitted. Here’s why this happens, and how you can change it.

Ankle-Brachial Index? It’s Easier Than You Think
Have you ever faced a seemingly daunting task, and so you do everything in your power to avoid it? Like renewing a driver’s license, for example. Or maybe cleaning out the refrigerator. But then once it’s done, you look back and say, “Hey, that wasn’t so bad!”

That’s kind of how it is when it comes to determining a patient’s ankle-brachial index (ABI). While this is a key component of the lower-extremity vascular exam, it’s often overlooked – and even omitted – just because it seems so overwhelming. Hang in there, folks: we’re here to help make it easier.

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Lower Extremity Ulcers: Go With the Flow

Wednesday, October 21st, 2015

Lower Extremity Ulcer - Is this Pressure?

Imagine, if you will, the following scene: a wound care clinician is asked to weigh in on a lower extremity ulcer consultation, and upon arrival is told that it’s a pressure ulcer. So she seeks more information about blood flow:

Clinician #1: Tell me about the blood flow to the lower extremity.

Clinician #2: It seems okay because pulses are palpable on the foot.

Clinician #1: Are there recent Ankle Brachial Index (ABI) assessments in order to obtain a much more reliable assessment of blood flow?

Clinician #2: Um … no.

Here’s the truth

Unfortunately, this kind of conversation happens all the time, so let’s set the record straight: palpation of pulses is not a reliable assessment of blood flow to the foot. They can be misleading and leave you hanging – without the information you need to properly and safely manage the wound.  An ABI will reveal what you need to know about the blood flow to the lower extremity, and give you vital clues to the underlying disease process causing the ulcer. Only when this information has been gathered can you properly develop a plan of care that will help, and not hurt, the patient.

The 2014 International Pressure Ulcer Guidelines mentions performing a vascular assessment on every lower extremity ulcer.  That means, at a minimum, we need to check pulses and toe measurements, and perform an ABI. This will assist in identifying the true cause of the wound, whether it be pressure, venous, arterial, or mixed venous/arterial.

What’s this about an ABI?

An ABI is considered the gold standard of tests that can be easily performed at bedside – all you need is a blood pressure cuff and a hand-held Doppler. It is also the most useful test to assess lower extremity arterial perfusion, and compares the systolic blood pressure of the ankle to that of the arm (brachial). When should you perform ABI?

  • When pulses aren’t clearly palpable or are weak
  • On all patients with lower extremity ulcers
  • When the ulcer is not healing
  • Always before starting compression therapy

Compression therapy is the standard of care for the treatment of venous stasis ulcers.  ABI results will help identify significant arterial disease and determine the amount of compression (if any) that can be applied safely. You never want to compress a lower extremity that has significant arterial flow compromise, for fear of cutting off all blood flow and causing harm to your patient.

Blood flow assessment is a must

Earlier, we used the example of a patient who has a possible “pressure ulcer.” When we are not sure of the type of wound we are treating, we need to ask some serious questions:

  • Could there be arterial blood flow compromise that will make healing problematic or even unrealistic?
  • Is there venous disease complicating the clinical picture that could benefit from appropriate levels of compression?
  • Or is this strictly a pressure ulcer where the treatment plan will require off-loading interventions first and foremost?

The bottom line

When assessing a lower extremity ulcer, it is vital to determine the assessment of blood flow.  Without the information obtained from an ABI, your care plan can be inappropriate, your goal setting can be unrealistic, and your patient could be harmed.

What do you think?

We want to know about your experiences with this topic. When do you typically obtain an ABI in practice? In long-term care settings, how often do you obtain ABI measurements? If you’re not obtaining ABIs, what are you using? Please share your experiences below.

 

WHY ABI?

Monday, October 20th, 2014

What exactly is an ABI?  ABI stands for Ankle Brachial Index. This is a non-invasive bedside tool that compares the systolic blood pressure of the ankle to that of Doppler_BloodPressureCuffthe arm. It is done to rule out Peripheral Arterial Disease in the lower extremities. The ABI is considered the “bedside” gold standard diagnostic test and can be done by any trained clinician in a clinic, hospital, nursing home and/or even the home care setting. All you need is a blood pressure cuff and a hand held Doppler.

Why do we do the Ankle Brachial Index or ABI?  Well, there are several reasons why we include the ABI as part of our assessment for the patient with lower extremity wounds. First of all, in order to heal a wound we have to be sure that our patient has adequate blood flow. The ABI will tell us if the patient has impaired arterial blood flow, and how significant that impairment is.  We also need to know the amount of compression that we can safely apply to the venous patient, in general the lower the patients ABI reading, the lower the amount of compression that can be safely applied.

When do I need to do the ABI? Standards of care and Guidelines dictate when we should be doing the Ankle Brachial Index. Our current standard of practice states to do the ABI: Anytime a patient has a lower extremity ulcer, when foot pulses are not clearly palpable, prior to applying compression wraps / garments or when the lower extremity ulcer is no longer healing.

What does the ABI “number” mean? First we need to be aware that not everyone’s ABI is reliable, in fact patients with diabetes or end-stage renal disease may have incompressible vessels rendering a falsely high ABI score. For these patients we use another diagnostic test called the Toe Brachial toe_cuf_wound_care_education_institutePressure Index (TBPI) instead of the ABI.  For those with ABI readings, in general as the patients ABI score decreases, this signifies that the patient has arterial disease of the lower extremity, and poor blood flow. Any patient with an abnormal reading needs a referral to a vascular specialist. Bedside interpretations of the ABI that we use as wound clinicians are: 1.0 considered a normal reading, an ABI of 0.9 indicate more venous, 0.6-0.8 indicate a mixed etiology (venous and arterial) and less than or equal to 0.5 is indicative of arterial disease of the lower extremity.

We as wound care clinicians are held to certain standards of care and must follow those guidelines established by the experts.  Performing the ABI on patients before applying compression and on patients with lower extremity ulcers is one of them.  As wound clinicians we use the ABI and our clinical assessment to help guide us into determining what type of ulcer we are dealing with so we can make appropriate referrals and develop the best treatment plan for our patients. It’s a step we can’t afford to leave out; our patient’s limb may depend on it.