Venipuncture Collection Sites and Tourniquet Application
KEYPOINTS below are from McCall and Tankersley, Phlebotomy Essentials, 5th edition
CAPTIONED:
WITHOUT CAPTIONING:
KEYPOINT
"According to CLSI Standards, an attempt must have been made to locate the median cubital vein on both arms before considering an alternate vein; because of the possibility of nerve injury and damage to the brachial artery, the basalic veinshould not be chosen unless no other vein is more prominent."
Proper Vein Selection
KEYPOINT:
A patent (open) vein is turgid (distended from being filled with blood), giving it a bounce or resilience with a tube-like feel. An artery has a pulse and must be avoided. This is why the thumb, which has a pulse, should not be used to palpate as it may lead you to think a vein is an artery.
Proper Cleansing of the Collection Site
KEYPOINT:
When using an alchol based cleanser, the evaporation and drying process helps destroy microbes, prevents hemolysis from alcohol decontamination, and avoids a burning sensation when the needle is inserted.
Proper Tourniquet Application
Tourniquets are used to make it easier to locate veins. This is accomplished as the tourniquet impedes venous blood flow right below the application site without impeding arterial blood flow. This causes the veins to become distended and more visible and palpaple
KEYPOINT:
According to CLSI, when a tourniquet is used during preliminary vein selection, it should be released after 2 minutes and then reapplied.
During the process of puncturing the vein with the needle the tourniquet should be removed within 1 minute. Failure to release the tourniquet within the stated time can lead to hemoconcentration (increased ratio of cellular components to plasma) and alter the true concentrations of many analytes.
During the process of puncturing the vein with the needle the tourniquet should be removed within 1 minute. Failure to release the tourniquet within the stated time can lead to hemoconcentration (increased ratio of cellular components to plasma) and alter the true concentrations of many analytes.