When should the nurse conduct an Allen’s test?
A.
Just before arterial blood gasses are drawn peripherally.
B.
Prior to attempting a cardiac output calculation.
C.
To assess for presence of a deep vein thrombus in the leg.
D.
When pulmonary artery pressures are obtained.
The correct answer and Explanation is :
The correct answer is:
A. Just before arterial blood gases are drawn peripherally.
Explanation:
The Allen’s test is a clinical procedure performed to assess the adequacy of collateral blood flow to the hand before drawing arterial blood gases (ABGs) from the radial artery. The radial and ulnar arteries are the primary arteries supplying blood to the hand. The Allen’s test helps ensure that the ulnar artery, which is the collateral artery, is providing sufficient blood flow to the hand in case the radial artery is compromised.
Here’s how the Allen’s test is conducted:
- Compression of Arteries: The nurse compresses both the radial and ulnar arteries simultaneously at the wrist.
- Hand Blanching: The patient is asked to make a fist to force blood out of the hand, making it pale.
- Release of Ulnar Artery: The ulnar artery is then released while the radial artery remains compressed.
- Reperfusion: The nurse observes the hand for color changes. The hand should rapidly regain its normal color if the ulnar artery is providing adequate blood supply.
If the hand does not rapidly return to its normal color, this suggests inadequate collateral circulation through the ulnar artery. In such cases, drawing ABGs from the radial artery might risk compromising the hand’s blood supply, making it crucial to avoid arterial puncture in this scenario.
The Allen’s test is not related to cardiac output calculations, deep vein thrombus assessment, or pulmonary artery pressure measurements. It is specifically used to ensure that the blood supply to the hand is sufficient when accessing the radial artery for procedures like arterial blood gas sampling. This precaution helps prevent complications associated with reduced blood flow to the hand, ensuring patient safety during and after the procedure.