What Are the Best Sites for Venipuncture?

Superficial venipuncture is a medical method based on anatomy.

Superficial venipuncture

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Superficial venipuncture is an application

Superficial veins are located in the subcutaneous tissue, also known as subcutaneous veins. They are superficial and easy to see through the skin. The number of superficial veins is large, and the multiple venous network is synthesized without arteries. Superficial veins have venous valves, which have more limbs and more lower limbs than upper limbs. Vein wall is thin, smooth muscles and elastic fibers are less, contractility and elasticity are poor, so when blood volume is significantly reduced, the vein wall collapses. Venous blood flow is slow, especially when the proximal end is oppressed or pressure is increased, and venous filling often occurs.

Site selection

According to age and condition, veins in different parts can be selected. Infants and young children mostly use the scalp veins and external jugular veins, followed by dorsal hand veins and dorsal foot veins. Adults often choose dorsal veins and dorsal veins.

Pass through levels

Although the selected vein sites are different, the levels of perforation are basically the same, that is, the skin, subcutaneous tissue, and vein walls. Due to different ages, the thickness, elasticity and hardness of the vein wall are different.

Needle injection technology and error prevention

On the extremities, a band is usually applied to the proximal end of the site to be punctured to fill the veins and facilitate puncture. Fix the skin and vein during puncture. The needle point is inclined upward, and the angle between the skin and the skin is 15 to 30 degrees. It penetrates into the skin on the surface or side of the vein, then sneaks in the direction of the vein near the heart, and then penetrates the vein. Insert the needle a little, lay the needle flat and fix it, draw blood or inject the drug, and fix the vein when puncturing, especially the elderly patients. The blood vessels are poor in elasticity and easy to slide. Do not use too much force to avoid penetrating the vein. If long-term intravenous administration is needed, the puncture site should start with the small vein first, and gradually select the puncture site upwards to increase the number of blood vessels. If it is a one-time blood test, you can choose the puncture median elbow vein. The puncture site should be avoided as much as possible to facilitate the needle fixation. There are many superficial vein valves in the extremities, and the puncture site should avoid the valve. When the jugular jugular puncture is performed, the child should be placed in the supine position, with his arms attached to his side, a pillow cushion under his shoulder, his head tilted to the opposite side of the puncture site, and lean back as far as possible to fully expose the puncture site so that the puncture needle can be used during puncture It is parallel to the vein, and it is usually inserted at the junction of the upper and the lower part of the vein. Because the scalp vein is fixed in the fibrous septum of the subcutaneous tissue, the wall of the tube has a poor ability to retract. Therefore, it is necessary to compress the local area after puncture to prevent bleeding from forming subcutaneous hematomas.