Venipuncture Definition

common spot for venipuncture

The commonly accepted venipuncture definition is that it is a procedure for enabling intravenous access for blood sampling or intravenous therapy. The analysis of blood is one of the most vital diagnostic tools available within healthcare. The data obtained from this procedure is highly dependable for interpretation of innumerable clinical signs and symptoms. It is one of most routinely performed procedures, through which diseases can be analyzed under a microscope. This helps in improving health and longevity by acting as a preventative measure.

Venipuncture Definition

syringe

image source:pexels

In venipuncture, the vein is punctured to draw a sample of blood. The most common area for drawing blood is the superficial vein of your forearm. However, phlebotomists or medical practitioners can draw blood from other places if needed. This procedure is performed by medical laboratory scientists, phlebotomists, paramedics, dialysis technicians, medical practitioners and other nursing staff in healthcare. Medical practitioners need to follow the procedures and steps as per the venipuncture definition.

Common Sites of Drawing Blood

venipuncture

image source:pexels

The most common venipuncture site is at the bend of the elbow, or the Antecubital Fossa. The Median Cubital Vein is close to the surface positioned within the Cubital Fossa. It is an ideal place for the purpose of venipuncture as there are no large nerves nearby. Other veins in this area include the Cephalic Vein and Basilic Vein.

In some cases, a medical practitioner or phlebotomist might choose another site for drawing blood. This is usually done when the technician is not comfortable with the three veins present in the bend of your elbow. Your healthcare professional might also choose another vein if the blood is not flowing properly through the Antecubital Fossa area. Other common sites include the dorsal vein in the hand or any vein in your feet. However, the veins in the feet are chosen only as a last resort.

Different Types of Venipuncture

Venipuncture definition states it is the process of getting intravenous access to draw blood. Hence, venipuncture also includes the process of starting an intravenous (IV) line. The venipuncture procedure is also used for administering medication, nutritional therapies, and chemotherapy.

Procedure

Venipuncture requires detailed knowledge and skills in order to be performed successfully and painlessly. It is a complex function that needs specific equipment, care, and caution.

Equipment Required

syringe

image source: pixabay

The equipment used varies with the type and purpose of venipuncture performed. However, some of the most commonly used items for this procedure are:

  •     Surgical Gloves
  •     Wipes/Swabs
  •     Tourniquet
  •     Collection tubes
  •     Needles
  •     Bandages
  •     Disposal Unit
  •     Gauze

Prepping for a Successful Venipuncture

surgery

image source: Pixabay

Step 1: Assemble Equipment

The medical professional should assemble all the equipment neatly on a tray. Make sure that the blood sample goes in for correct testing.

STEP 2: PATIENT PREPPING

In this step, a healthcare professional will make sure that the patient is comfortable and calm. There are certain guidelines that need to be followed when you meet the patient. The phlebotomist will ask the name and identity of the patient clearly and also explain the purpose for venipuncture to the patient. Allergies of any kind should be identified and labeled properly.  Due precautions need to be taken in case the patient suffers from any sort of allergies. Other information such as complications during a prior venipuncture, dietary habits, fasting restrictions, and current medical treatment are also obtained.

STEP 3: VEIN DETECTION

The patient’s arm is extended and placed on a table or any flat surface to perform the procedure only after seeking verbal consent. The healthcare professional will probe gently in the area inside of the elbow to search for a vein. There is a maximum risk when using the Basilic vein, as doing so increases the risk of damaging an artery or a nerve.

The Basilic vein is also the most painful to draw from of the three major veins within the Cubital Fossa. The Median Cubital Vein is the ideal vein to draw blood from as it is good-sized and does not have any close proximity to other arteries and nerves. A tourniquet is tied right above the vein site at a distance of 3–4 inches. This makes the vein pop up and become more visible.

STEP 4: HAND PREPPING

While the tourniquet does its job, the healthcare professional preps his/ her hands. They may either go and wash before donning surgical gloves or simply cleanse with an alcohol rub. This step can also be performed before tying the tourniquet. However, it is critical that a fresh pair of surgical gloves be used every time to prevent contamination and an infection.

STEP 5: SITE DISINFECTION

The venipuncture area needs to be disinfected to prevent contamination. Alcohol is the best solution for disinfecting as it does not affect lab results as compared to povidone iodine. A 70% alcohol swab should be used to cleanse the site, wiped in a circular motion. The cleansing begins from the exact venipuncture point and moves outwards to at least 2–3 cm.

Procedure to Draw Blood

injecting medical shot

Image Source: Pixabay

Venipuncture can be performed only after the site has been prepped. The medical practitioner will place a thumb under the vein to anchor it. Care is maintained to prevent touching the exact site of venipuncture. The patient is requested to curl their fingers into a tight ball shape of the fist. The correct way to insert a needle into the vein lumen is to do so quickly and at an angle between 15 to 30 degrees by stretching the skin taut. Healthcare professionals are instructed not to cause excessive trauma by probing. The tourniquet is released once blood is collected. If multiple tubes are being collected, then the tourniquet is released before filling the last tube. It is critically necessary to release the tourniquet before removing the needle.

The needle should be removed in a single swift motion to prevent additional pain. Pressure with gauze is applied as soon as the needle is withdrawn to prevent any blood loss and hematoma. All tubes should be properly labeled and sent to the laboratory for testing. Any specific laboratory requirements are completed at this time. For instance, some laboratories require the test tube to be inverted multiple times.

A very important step in venipuncture is the destruction of needles and other items that touched blood. Needles are preferably discarded in a "Sharps" container while items that did not touch blood are thrown with general waste. The venipuncture site is inspected to check for bleeding or any other complications.

Precautions

health medicine

Image Source: Pixabay

There are some areas that should not be chosen as a venipuncture site. These include areas where there are extensive scars or burn injuries. The arm on the side where a mastectomy has been performed and edematous extremities should also be avoided. Accumulated tissue fluids in edematous extremities can alter test results.

It is not advisable to perform a venipuncture on the arm where there is already an IV. The other arm should be used for drawing blood in such a situation. However, if there is no other way, then the IV should be turned off for at least 2 minutes and another vein used for drawing blood. An existing IV line might make it easier to draw blood as compared to venipuncture. However, the IV line should first be flushed thoroughly. Blood should be drawn slowly to avoid hemolysis. Blood should also not be drawn from the arm containing a cannula, heparin lock or fistula.

Purpose

Venipuncture definition states a variety of benefits of this procedure. It is among the most routinely performed invasive procedures. It is also among the most important diagnostic tools available to healthcare professionals. Here are the common uses of venipuncture.

Diagnostics

The first step to identifying any illness or sickness is to study a patient’s blood sample under the microscope. As per venipuncture definition, blood is obtained from the veins for laboratory testing to check for pathogens and other undesirables.

Monitoring

There area number of blood components that can cause severe damage to the body if present in inadequate or excess quantities. Real-time monitoring of blood components can be carried out by drawing blood and testing it.

Administration

Venipuncture definition states that it can be used to administer intravenous therapies. This includes administering treatments such as chemotherapy and medications. It can also be used to provide nutrition to the body through intravenous therapies.

Removal

The major purpose of this procedure as per the venipuncture definition is to take a blood sample from the body. It can either be done for testing purposes or to regulate blood levels in the body. For instance, red blood cells require being removed when iron and erythrocytes are in excess.

Blood Storage

Venipuncture is useful in collecting blood to be used later. For instance, blood transfusion begins with the procedure of collecting blood through a venipuncture.

Conclusion

vaccination set

Image Source: Pixabay

Venipuncture definition states it is the procedure of collecting blood by getting intravenous access. There are several factors that need to be taken into consideration while taking blood. Patient consideration is of primary importance. Venipuncture procedure requires specific equipment, knowledge, and skill to be performed successfully. Venipuncture can facilitate holistic and timely treatment.

Author: Emma Campbell

I am a director at the Phlebotomy Training Institute