Phlebotomy Butterfly Technique: Bloodletting with a Winged Syringe
In a previous article, we discussed the evolution of phlebotomy as a medical procedure. It may not be as widely used as before, but it is still the go-to treatment for a select number of conditions. These include:
- Polycythemia vera – a bone marrow disorder pertaining to stem cells, resulting in an overproduction of red blood cells. Phlebotomy is used to reduce cell mass and prevent clots.
- Porphyria cutanea tarda – refers to a group of disorders of heme metabolism. An associated abnormality in iron metabolism is also present. The bloodletting process is used to bring down iron levels in the body.
- Hemachromatosis – this genetic disorder leads to the abnormal accumulation of iron in the liver, pancreas, liver, heart, pituitary, joints, and skin. Periodic bleeding maintains ferritin at a reasonable level, minimizing iron deposition.
Instruments used to draw blood from patients also underwent a major improvement. Gone are the crude (and dangerous). The fleam (a foldable device with multiple sized blades) and the scarificator (a cube-shaped brass box with several small blades) have been abandoned. Meanwhile, the lancet has evolved and continues to be used in modern medicine.
Sophisticated instruments also meant modern techniques. Let’s have a deeper look at one of them.
The phlebotomy butterfly technique is the process of drawing blood by means of a ‘winged’ apparatus. While medical technicians and nurses are allowed to draw blood, this procedure should only be done by a trained phlebotomist.
Tools
- Butterfly wingset
This is a device used for accessing a superficial vein. It is made up of a hypodermic needle, two bilateral flexible ‘wings’, flexible small-bore transparent tubing (20 to 35 centimeters long), and a connector. Newer models of this apparatus include a slide and lock safety device. This is slid over the needle after use to prevent accidental needlestick injury (http://www.ccohs.ca/oshanswers/diseases/needlestick_injuries.html).
- Vacutainer and syringe
The butterfly wingset’s connector is usually attached to another device. In the case of bloodletting, this is a vacuum tube holder or hub (Vacutainer) and a syringe.
A Vacutainer is a sterile glass or plastic tube with an evacuated closure. This creates a vacuum inside the tube, facilitating the draw of a predetermined volume of liquid. The tube is available with or without a safety-engineered closure. Additionally, there are a variety of labeling options, closure colors, and draw volumes to choose from. In some cases, the tube may contain additives for stabilizing and preserving a blood specimen before tests are made on them.
Selecting the site
The procedure starts off with determining the area that will be punctured. This is usually found somewhere along the arm.
Cleaning the site
The site is then cleaned using circular motions. It should begin at the center and move outward in concentric circles. The pressure applied should only be enough to remove surface dirt. The patient should not feel a burning sensation while this is being done. Gloves should be used for sanitation purposes.
After applying the cleaning agent, the area has to dry to avoid hemolysis (the rupture of red blood cells) in the blood specimen. This can be brought about by residual alcohol. The physician typically makes use of this time to assemble the supplies, if he has not done so already.
This task could involve the following steps:
- Remove the adapter from the butterfly (winged infusion set).
- Pull back on the plunger to break the seal on the syringe.
- Attach the syringe to the butterfly at the adapter or connector.
- Choose the microcontainers needed.
Locating the vein and applying the tourniquet
The physician palpitate the area to get an idea of the vein’s size, angle, and depth. The antecubital (inside elbow) area of the arm is one of the most common sites. Once located, a special chemical could also be applied to the site to make it more visible.
A tourniquet also assists the phlebotomist in finding a suitable vein for blood extraction. It is applied three to four inches above the puncture site. The implement should be tight enough to restrict blood flow in the veins, but not in the arteries.
Here are the steps for proper tourniquet application:
- Wrap the tourniquet around the arm or leg. Ensure that it is placed two to four inches (5.1 – 10.2 centimeters) away from the site
- Secure the band in place using an overhand knot. This is done by taking one end of the tourniquet and creating a ‘roller coaster loop’ Insert either end and pull it tightly.
It’s important to remember that the tourniquet should never be left on the arm for more than a minute. Doing so might lead to hemoconcentration. This refers to the increase in large molecules such as cells, proteins and coagulation factors. If the physician asks the patient to make and unmake a fist, the same should be observed.
The band should be as soon as blood flow is established in the tube. However, this should be done before the needle is taken out. The blood may be forced out of the puncture site if this sequence is not followed. This can contaminate the area and bruise the patient’s arm.
Inserting the needle and sample collection
When inserting the needle, the steps are:
- Pinch the flexible wings together and place the bevel in an upward position.
- Anchor the vein and smoothly insert the needle. This should be done carefully and properly. Otherwise, the butterfly may turn over.
- Carefully rotate the needle so as to be sure that the bevel is up.
- Collect the proper amount of blood into the syringe. To do this, gently pull back on the plunger. This allows the tube to be filled with blood.
- Remember to double check the amount that should be extracted beforehand to ensure accuracy.
A phlebotomist is often permitted two unsuccessful venipunctures per patient. Before a third one is attempted, a lead medical technician should be consulted. It may be necessary to look for another location for the puncture.
A clean sterile needle is necessary for each new collection attempt. It should be one that’s disposable and must never be re-used.
Transferring blood into microcollection tubes
- Pinch off the butterfly tubing where it connects to the syringe.
- Withdraw the needle from the vein. After doing so, pull back on the plunger. This removes the blood from the winged infusion set tubing.
- Fill the microcontainers.
On bleeding
Bleeding is the losing blood from the vessels when damaged. A bleed can be something minor or life threatening. Applying direct pressure on the site is usually enough to stop this.
When blood is drawn via the butterfly technique, the damage caused is very little. Thus, the blood flow stops within minutes. Puncture wounds, on the other hand, don’t bleed very much. They are dangerous due to the risk of infection. If this happens, seeking medical care is vital.
Phlebotomy and children
Earlier, we’ve pointed out the importance of having an expert do the phlebotomy butterfly technique. In the case of children, expertise is an even bigger ‘must’. Skin puncture in pediatric patients should only be performed by a professional trained specifically for the procedure. Additionally, an understanding of a child’s psychological development and good interpersonal skills are also essential.
What can be done if the blood is viscous and clots too much during phlebotomy resulting in insufficient blood removal?
Drinking water helps blood flow better and makes the veins more likely to stick up and be found easily (even if the patient is fasting)
What to considar do if the blood sample is unobtainable?
1. Change the position of the needle. If the needle has penetrated too far into the vein, pull it back a bit. If it has not penetrated far enough, advance it farther into the vein. Loosen the tourniquet. It may have been applied too tightly, thereby stopping the blood flow. Re-anchor the vein. Veins sometimes roll away from the point of the needle and puncture site.
What to do if the blood stops flowing into the tube?
The vein may have collapsed, this is usually occurs insmaller veins and veins of geriatric patients due to: withdrawing too quickly with syringe inappropriate needle selectionIn this case resecure the tourniquet to increase venousfilling. If this is not successful, remove the needle, take careof the puncture site, and redraw.Blood collection from cannulaIn general, blood should not be drawn from an arm with a cannula because intravenous therapy(IV) fluid may dilute the specimen or give false results.
Otherwise follow these procedures:
1) Stop any infusion into the cannula for at least 10 minutes.
2) With a syringe attached to the hub of the cannula, gently aspirate 1 ml then discard it as it is contaminated with infusion fluid.
3) With a syringe, aspirate the volume of blood required for your specimen. Note You cannot use this blood for a coagulation studies if heparin has been run through the cannula as even a trace amount of heparin in the cannula will substantially change the result.
The Vacutainer System consists of:
1. A double-pointed needle (Vacutainer needle), the long end of the needle is used for penetrating the vein; the shorter end is used to penetrate the vacuum tube.
2. A plastic holder into which the phlebotomist screws the double pointed Vacutainer needle.
3. A series of vacuum tubes with rubber stoppers of various colors. The air pressure inside the tube is negative, less than the normal environment so the difference in pressure between the inside of the tube and the vein causes blood to fill the tube.
Hope that sheds some light.
Thank you so much for this aricelt, it saved me time!