How far above the venipuncture site should a tourniquet be applied?

The appropriate placement of a tourniquet is 3-4 inches above the venipuncture site. This distance ensures that the tourniquet effectively occludes the venous blood flow while allowing sufficient arterial flow to keep the tissues viable. Placing the tourniquet too close to the site might result in excessive pressure on the area or could cause discomfort to the patient, while placing it too far away may not sufficiently engorge the veins for successful access.

In practice, a tourniquet is used to make veins more prominent by pooling blood in the vessels. The 3-4 inch range is optimal for achieving this goal without compromising patient comfort and safety. Properly applied, it allows for efficient venipuncture while minimizing risks, such as the formation of hematomas or the discomfort that can arise from improper placement.