The nurse knows that preventing breakage of the cannula is important because:
1) A foreign body in the vein can cause infection.
2) The piece left in the vein can become a fatal embolus.
3) A foreign body in the vein can stimulate an immune response, which can include anaphylactic shock.
4) The piece left in the vein can irritate the vein's inner lining, leading to phlebitis.
Phlebotomy is the practice of drawing blood from patients to gather data about their health. As a phlebotomist, it is critical to know which vein sites offer stable flows for blood draws. There are three phlebotomy vein sites located in the arm most utilized by medical professionals and three additional draw sites that are last resorts.
What is Antecubital Fossa?
The antecubital fossa is a collection of veins located within the arm’s inner area, opposite of the elbow, where the arm folds in. In this elbow pit, phlebotomists have easy access to the top three vein sites used in phlebotomy:
- Median cubital vein
- Cephalic vein
- Basilic vein
Median Cubital Vein
The median cubital vein, also known as the antecubital vein, is the most common vein for phlebotomy. Located in the antecubital fossa, the median cubital vein is a well anchored, stable vein that rarely rolls during venipuncture.
Why is the Median Cubital Vein Used the Most?
The median cubital vein is used the most for its accessibility. It is large and near the skin’s surface, making it easier for phlebotomists to see before anchoring the vein. The median cubital creates less bruising and pain than other draw sites.
Within the antecubital fossa, this vein poses the least amount of risk. Unlike the cephalic and basilic veins, the median cubital vein is not near major nerves or arteries.
Other Commonly Used Veins
The cephalic vein is a safe secondary option if the median cubital vein is not working. This vein can be found along the upper arm to the thumb, but it is commonly drawn from the forearm or antecubital fossa area.
Also found in the antecubital fossa, the basilic vein serves as a last resort for blood draws. It is not as close to the skin surface as the median cubital and cephalic veins, which poses a greater risk of damage to the median nerve and brachial artery.
While the median cubital, cephalic, and basilic veins are the most popular draw sites for blood draws, phlebotomists may resort to other draw sites if their ability to draw is restricted. Patients who are dehydrated, obese, terminally ill, or ‘hard sticks’ often get their blood drawn in other locations rather than the antecubital fossa.
The dorsal venous network is the next most common vein site for phlebotomists. Dorsal hand veins are often utilized for intravenous infusions but are viable options for blood draw sites. However, drawing blood from the hand is affiliated with higher levels of pain and less control. As a countermeasure, phlebotomists anchor the vein with their hand to stabilize it for the draw.
How to Choose the Right Vein for a Blood Draw
Phlebotomy is not a one size fits all; each patient is different and may have their blood drawn at other sites with varying needle sizes.
The first step to choosing the right vein is to select the appropriate needle gauge. While most patients’ veins are compatible with a standard needle gauge, others require a butterfly needle. Asking the patient about their previous blood draw experiences is beneficial, especially if they are a hard stick and know which area works best.
After the needle selection, phlebotomists begin to look and feel for a viable vein. The first attempt is the antecubital fossa area, starting with the median cubital vein, then the cephalic vein, and the basilic vein. If none of these veins work, then the phlebotomists use the hand veins. Other draw sites, particularly below the waist, are rarely used.
What Areas Should You Avoid Drawing From?
While hand veins may be utilized for blood draws and intravenous infusions, veins in the feet and legs should be avoided for adults. Drawing from these sites can cause blood clotting and hemostasis. In some instances, the legs or feet are required for use, but a physician or doctor should be completing the draw, not a phlebotomist.
Areas of the body that look infected, scarred, or burned must also be avoided. When working with patients who have undergone a mastectomy, draw from the arm on the opposite side of the mastectomy to avoid edematous tissue.
PhlebotomyU CPT-1 Course
PhlebotomyU offers Certified Phlebotomy Technician (CPT I) courses for aspiring phlebotomists. Our students gain a vast amount of experience with phlebotomy vein sites through our hands-on and engaging curriculum and externship program.
To request course information, contact PhlebotomyU today.