A client goes into respiratory distress, and blood for an arterial blood gas assessment is drawn from the radial artery. The nurse performs Allen's test before the blood is drawn to determine the adequacy of the?

1. A

   Ulnar circulation

2. B

   Carotid circulation

3. C

   Brachial circulation

4. D

   Femoral circulation

Appeared in: DHS 2018 shift 1st

Explanation

• The Allen's test is performed before a radial artery puncture to confirm that the ulnar artery provides adequate collateral blood flow to the hand.
• This is a critical safety measure to ensure the hand remains perfused with blood if the radial artery is damaged or becomes occluded during the procedure.
• A positive test (rapid return of color to the palm after releasing pressure on the ulnar artery) indicates the procedure can be safely performed on that wrist.

Why Other Options Were Wrong

• Option B: The carotid arteries are located in the neck and are responsible for supplying blood to the brain and head, not the hand.
• Option C: The brachial artery is the main artery of the upper arm that divides into the radial and ulnar arteries. Allen's test assesses the collateral flow from the ulnar artery, not the primary flow from the brachial artery.
• Option D: The femoral artery is the main artery supplying blood to the lower extremities (legs). It has no role in the circulation of the hand.

Related Visual

Clinical Relevance

• Nursing practice connection: Safe nursing care depends on performing Allen's test and collateral circulation assessment before arterial puncture in the correct sequence, documenting the action clearly, and monitoring for the expected response.
• Performing Allen's test is a fundamental nursing responsibility and a critical patient safety measure to prevent ischemic injury to the hand, a severe complication of radial artery procedures.
• A negative or equivocal Allen's test (color does not return promptly) is a contraindication for using that radial artery. The nurse must then assess the other wrist or notify the provider to consider an alternative site (e.g., brachial or femoral artery).
• What if? If the patient is unconscious and cannot make a fist, the nurse can still perform the test by elevating the patient's hand and passively opening and closing it to help exsanguinate the blood before compressing the arteries.

How to Approach the Question

• First, identify the key procedure mentioned in the question: an arterial blood gas (ABG) draw from the radial artery.
• Next, recognize the specific assessment being performed: the Allen's test.
• Recall or deduce the purpose of the Allen's test. It's a safety check performed before interfering with a major artery.
• Think about the anatomy of the hand's blood supply. The hand is supplied by two arteries: the radial and the ulnar, which connect in the palm.
• Logically conclude that if a procedure involves the radial artery, the test must be checking the competency of the other artery (the ulnar artery) to ensure it can supply the whole hand by itself if needed.
• Eliminate the other options by identifying their anatomical locations: Carotid (neck), Brachial (upper arm), and Femoral (leg), all of which are incorrect for hand circulation.

Concept Tested & Keywords

• Concept Tested: Allen's test and collateral circulation assessment before arterial puncture.
• Stem keywords: respiratory distress, arterial blood gas, radial artery, Allen's test
• Lead-in keywords: adequacy of the
• Clinical cues: Procedure: Arterial blood gas assessment
• Clinical cues: Anatomical site: Radial artery

Question ID

Qty8CIaahLb9TqLvb-071x

Copy ID

Reference Book

E6 Anatomy Grays 43e Vol 2 Part 2 p. 73-75

E6 Nursing Fundamentals Potter Perry 12e Part 5 p. 79-81

E6 Nursing Brunner Adult Health 3SA Vol 1 Part 2 p. 118-120