Allen's test

Revision as of 19:52, 14 March 2016 by WikiBot (talk | contribs) (Bot: Adding CME Category::Cardiology)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to navigation Jump to search
Allen's test
Error creating thumbnail: File missing
Arteries of the hand

WikiDoc Resources for Allen's test

Articles

Most recent articles on Allen's test

Most cited articles on Allen's test

Review articles on Allen's test

Articles on Allen's test in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Allen's test

Images of Allen's test

Photos of Allen's test

Podcasts & MP3s on Allen's test

Videos on Allen's test

Evidence Based Medicine

Cochrane Collaboration on Allen's test

Bandolier on Allen's test

TRIP on Allen's test

Clinical Trials

Ongoing Trials on Allen's test at Clinical Trials.gov

Trial results on Allen's test

Clinical Trials on Allen's test at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Allen's test

NICE Guidance on Allen's test

NHS PRODIGY Guidance

FDA on Allen's test

CDC on Allen's test

Books

Books on Allen's test

News

Allen's test in the news

Be alerted to news on Allen's test

News trends on Allen's test

Commentary

Blogs on Allen's test

Definitions

Definitions of Allen's test

Patient Resources / Community

Patient resources on Allen's test

Discussion groups on Allen's test

Patient Handouts on Allen's test

Directions to Hospitals Treating Allen's test

Risk calculators and risk factors for Allen's test

Healthcare Provider Resources

Symptoms of Allen's test

Causes & Risk Factors for Allen's test

Diagnostic studies for Allen's test

Treatment of Allen's test

Continuing Medical Education (CME)

CME Programs on Allen's test

International

Allen's test en Espanol

Allen's test en Francais

Business

Allen's test in the Marketplace

Patents on Allen's test

Experimental / Informatics

List of terms related to Allen's test

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Synonyms and keywords: Allen test

Overview

In medicine, Allen's test, is used to test blood supply to the hand. It is performed prior to radial arterial blood sampling or cannulation.

Historical Perspective

It is named after Edgar Van Nuys Allen.[1]

The Allen's Test

  1. The hand is elevated and the patient/person is asked to make a fist for about 30 secs.
  2. Pressure is applied over the ulnar and the radial arteries so as to occlude both of them.
  3. Still elevated, the hand is then opened. It should appear blanched (pallor can be observed at the finger nails).
  4. Ulnar pressure is released and the color should return in 7 secs.

Inference: Ulnar artery supply to the hand is sufficient and it is safe to cannulate/prick the radial.

If color does not return or returns after 7 seconds, then the ulnar artery supply to the hand is not sufficient and the radial artery therefore cannot be safely pricked/cannulated.

Anatomical Basis

The hand is normally supplied by blood from the ulnar and radial arteries. The arteries undergo anastomosis in the hand. Thus, if the blood supply from one of the arteries is cut off, the other artery can supply adequate blood to the hand. A minority of people lack this dual blood supply.

Significance

An uncommon complication of radial arterial blood sampling / cannulation is disruption of the artery (obstruction by clot), placing the hand at risk of ischemia. Those people who lack the dual supply are at much greater risk of ischemia. The risk can be reduced by performing Allen's test beforehand. People who have a single blood supply in one hand often have a dual supply in the other, allowing the practitioner to take blood from the side with dual supply.

The utility of the Allen's test is questionable,[2] and no direct correlation with reduced ischemic complications of radial artery cannulation have ever been proven. In 1983, Slogoff and colleagues reviewed 1,782 radial artery cannulations and found that 25% of them resulted in complete radial artery occlusion, without apparent adverse effects.[3] A number of reports have been published in which permanent ischemic sequelae occurred even in the presence of a normal Allen's test.[4][5] In addition, the results of Allen's tests do not appear to correlate with distal blood flow as demonstrated by fluorescein dye injections[6] or photoplethysmography.[7]

Modifications to the test have been proposed to improve reliability.[8]

References

  1. Template:WhoNamedIt
  2. Jarvis MA, Jarvis CL, Jones PR, Spyt TJ (2000). "Reliability of Allen's test in selection of patients for radial artery harvest". Ann. Thorac. Surg. 70 (4): 1362–5. PMID 11081899. Unknown parameter |month= ignored (help)
  3. Slogoff s, Keats AS, Arlund C. On the safety of radial artery cannulation. Anesthesiology 1983; 59:42-7
  4. Thompson SR, Hirschberg A: Allen's test re-examined. Crit Care Med 16:915, 1988
  5. Wilkins RG: Radial artery cannulation and ischaemic damage: A review. Anaesthesia 40:896-899, 1985
  6. McGregor AD: The Allen test-an investigation of its accuracy by fluorescein angiography. J Hand Surg [Br] 12:82-85, 1987
  7. Stead SW, Stirt JA: Assessment of digital blood flow and palmar collateral circulation. Int J Clin Monit Comput 2:29, 1985
  8. Asif M, Sarkar PK (2007). "Three-digit Allen's test". Ann. Thorac. Surg. 84 (2): 686–7. doi:10.1016/j.athoracsur.2006.11.038. PMID 17643672. Unknown parameter |month= ignored (help)

Template:Eponymous medical signs for circulatory and respiratory systems

Template:WH Template:WS CME Category::Cardiology