Anesthesia Technologist Practice Exam

When is an Allen's test typically performed?

1. To assess cardiac function

2. To check for respiratory distress

3. To assess radial/ulnar artery blood flow

4. To determine blood gas levels

The correct answer is: To assess radial/ulnar artery blood flow

The Allen's test is specifically designed to evaluate collateral circulation between the radial and ulnar arteries in the wrist. This is crucial for assessing the blood flow to the hand before procedures such as arterial line placement or drawing arterial blood gases. By checking the adequacy of blood flow from both arteries, the Allen's test ensures that the hand will still receive sufficient blood supply if one of the arteries is occluded or damaged during a procedure. The other options, while they pertain to important aspects of patient care, are not the focus of the Allen's test. For instance, cardiac function involves assessing heart health through different methods, and respiratory distress focuses on evaluating the patient's breathing and oxygenation status. Additionally, determining blood gas levels involves other techniques and does not directly relate to the Allen's test but rather relies on direct arterial blood sampling from the appropriate sites. Thus, choice C is correct as it aligns directly with the purpose and methodology of the Allen's test in assessing arterial blood flow.