Venipuncture is used by phlebotomists or other medical personnel to obtain blood for medical testing when ordered by a doctor. Venipuncture is both an art and a science. You must understand anatomy, but be able to put the patient at ease and obtain the blood sample with a minimum of discomfort.
The perfect venipuncture patient is one who is young, thin, and has strong veins. This is not the type of patient you will see for blood work on a regular basis. You will have to draw blood from patients who are too obese to feel the veins, too dark skinned to see the veins, elderly patients with fragile veins, or a newborn that has to have blood taken from a tiny scalp vein.
Patients with small or fragile veins usually benefit from the use of a butterfly needle. This is a tiny gauge needle that gets its name from the plastic “wings” that enable you to hold on to it or tape it down while drawing the blood. It is attached to a tube with an end that allows you to draw or use a vacuum container to obtain the blood.
When using a butterfly, advance the needle only until you get a blood return or you will go through the tiny vein.
If your patient has very dark skin you may not be able to see the veins at all. If they are also obese you might not be able to feel the vein either. Using a strong penlight close to the skin will highlight the vein in red. This trick can help you locate a vein on the most difficult patients.
When palpating the vein make sure it doesn’t have a pulse (this would be an artery), and try to avoid valves in the vein. With practice you will be able to feel the valves. If you are going to use the anticubital space (inside the elbow), place a pillow behind the elbow to help the patient keep the arm straight and make sure the area isn’t scarred from overuse.
Venipuncture should not be performed on an extremity that has an IV running, or on an arm that is on the side where a mastectomy was performed.
The most common complication of drawing blood is bruising. This happens when the vein leaks a small amount of blood out under the skin. It is painless and resolves itself in a few days.
If a patient’s vein is fragile you may do a perfect venipuncture only to have the vein immediately “blow”. When this happens a large bruise forms and swells. You should immediately remove the needle, treat the site, and obtain the blood from a different site.
Another complication you may run into is a patient with a severe needle phobia. They may become dizzy, or faint. Find out how your patient has reacted in the past to such events and make any necessary adjustments to insure their safety.
Even with good knowledge of anatomy a venipuncture can sometimes get too close to a nerve and cause the patient extreme pain and a burning sensation. Withdraw the needle and choose another location. The pain should resolve itself fairly quickly.
Invasive procedures are a necessary part of medical diagnosis and treatment, and blood draws are one of those necessary procedures. Experienced phlebotomists and medical personnel see this as a routine procedure, but it is important to remember that patients do not usually view venipuncture as routine.