NCLEX Practice Test 2025 - Free NCLEX Practice Questions and Study Guide

The purpose of using a tourniquet during venipuncture is to engorge the vein. When a tourniquet is applied above the site where the needle will be inserted, it temporarily restricts venous blood flow back to the heart. This influx of blood volume into the vein causes it to become fuller and more prominent, making it easier for the healthcare provider to identify and puncture the vein.

Engorging the vein is particularly important in situations where the veins are in deep tissue or are not easily visible. By making the vein more pronounced, the tourniquet facilitates a successful venipuncture, which is crucial for obtaining blood samples or administering intravenous therapy.

Other choices may not accurately describe the role of a tourniquet. It does not numb the area, as local anesthesia would be required for that purpose. While a tourniquet aids in the collection of blood, its primary function is not to prevent bleeding after the puncture; other methods, such as applying pressure after the needle is withdrawn, serve that purpose. Lastly, a tourniquet is not used to locate arteries, as arteries are located deeper than veins and typically do not respond in the same way as veins when a tourniquet is applied.