Ankle-Brachial Index and Transcutaneous Oxygen Measurement Before Compression Therapy
by Lindsay D. Andronaco RN, BSN, CWCN, WOC, DAPWCA, FAACWS
Patients who come in with venous insufficiency ulcers and lower extremity arterial disease (LEAD) should be evaluated for compromised vascular status and the use of compression. The purpose of the ankle-brachial index (ABI) test is to support the diagnosis of vascular disease by providing an objective indicator of arterial perfusion to a lower extremity.
In 2013, the Journal of Wound, Ostomy Continence Nurses reviewed an article on indications for ABI. Some of the indications addressed in this article included:
• Assessment of patients with lower extremity wounds to rule out LEAD.
• In patients with suspected LEAD, diagnosis of arterial disease.
• Diagnosis of intermittent claudication.
• Age factors: patients over 50 years of age with a history of diabetes or tobacco use, and patients over 70.
• Adequate arterial blood flow in lower extremities determined prior to compression therapy, or debridement of wound:
o If the ABI is less than 0.8, sustained, high compression (i.e., 30–40 mmHg at the ankle) is not recommended.
o In patients with mixed venous/arterial disease (ABI is > 0.5 to < 0.8), reduced compression levels (23–30 mmHg) are recommended. If the ABI is less than 0.5, compression should be avoided and the patient referred to a vascular specialist for further testing and evaluation.
• Assessment of patient's wound healing factors and potential.
An Example of Compression Without ABI
A home care nurse was given orders by a primary care provider (PCP) who wrote to compress a patient's venous insufficiency ulcer with an Unna boot. The nurse went out, did her nursing assessment including medications, nutrition, fall risk, and wound assessment. She treated the wound over a one month period. It continued to just worsen and the patient was sent back to see his PCP.
The PCP felt a pulse on the affected extremity, and said that they should continue the Unna boot application and follow up with a vascular consult. He didn't feel that it was an immediate issue as there was a pulse. The vascular consult was in another 3 weeks.
Another week passed and VNA nurse became worried about the leg, as now it was becoming ischemic. When the VNA called the PCP's office, the triage nurse said to just wait for the vascular consult.
The patient was admitted to the hospital where they did ABIs and toe pressures/transcutaneous oxygen measurements (TCOM) to evaluate the blood flow. This patient was an emergent vascular case due to the occlusive disease and ischemic toes.
This patient ended up with a below the knee amputation (BKA).
When the PCP was later asked about why he continued the Unna boot applications without obtaining vascular studies first, he claimed he didn't know much about ABIs or TCOMs, but felt a pulse. He assumed that if you felt a pulse then it was acceptable to place compression. It was deemed later by a court decision that he was negligent for not obtaining the proper studies before applying compression over compromised vessels.
Literature to support ABI/TCOM in LEAD
It is widely noted in the literature that vascular status must be assessed before applying compression. Many institutions have this in their policies. The WOCN Society states in their best practice guideline that an "ABI provides documentation of adequate arterial blood flow in lower extremities before using compression therapy." Please visit the sources below for best practice clinical guidelines for ABIs.
Ankle Brachial Index: Quick Reference Guide for Clinicians. Journal of Wound, Ostomy & Continence Nursing. 2012;39(2S): S21–S29. Available at: http://journals.lww.com/jwocnonline/Fulltext/2012/03001/Ankle_Brachial_I...
Nursing Home Pressure Ulcer Toolkit. Qsource [Website]. Available at: http://www.qsource.org/toolkits/pressureUlcer/docs/articles/whitePapers/...
About the Author
Lindsay (Prussman) Andronaco is board certified in wound care by the Wound Ostomy Continence Nursing Certification Board. She also is a Diplomate for the American Professional Wound Care Association. Her clinical focus is working with Diabetic Limb Salvage/Surgical/Plastic Reconstruction patients, though her interests and experience are varied and include surgical, urological and burn care, biotherapeutics and Kennedy Terminal Ulcer research. Lindsay is the 2011 recipient of the Dorland Health People's Award in the category of 'Wound Ostomy Continence nurse' and has been recognized in Case In Point Magazine as being one of the "Top People in Healthcare" for her "passionate leadership and an overall holistic approach to medicine."
Lindsay is board certified in wound care by the Wound Ostomy Continence Nursing Certification Board. She also is a Diplomate for the American Professional Wound Care Association. In 2011, Lindsay was honored with the Dorland Health People's Award in the category of 'Wound Ostomy Continence nurse.'
The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, Kestrel Health Information, Inc., its affiliates, or subsidiary companies.