Among the three methods of venipuncture, the butterfly system or winged infusion set, is probably the easiest to use and control when drawing blood for a blood test.
The butterfly comes with a needle that is connected to a tubing on one end and on the other end of the tubing there is a connector that can be attached to a syringe or a tube holder. The length of a standard needle is about 3/4 inch. The needle sizes vary from 18 to 27, but the most common ones for blood draw are the 21, 22, and 23 gauges.
The butterfly is smaller in size than the other methods, thus making it very convenient for use in difficult locations, like at the back of the hand or below the arm.
There are many instances when a phlebotomist should use a butterfly to draw blood. Some of these may overlap with the syringe method, as there are times when either method could be used given the situation.
Different labs, hospitals, or doctors’ offices have varying polices and guidelines around butterfly needles and their use. Follow the stipulated guidelines wherever you are.
Here are 7 indications when you should use the winged infusion set:
1. Use for infants/babies
Infants or babies have small and tender veins. The butterfly needle or the syringe is the method to use. The butterfly is perfect for babies, as it gives the phlebotomist a lot of flexibility and control as he/she attempts to draw blood from these patients.
Their arm is also small and short, thus making the winged infusion set a good fit for them.
They can also move a lot when drawing blood from them and therefore the butterfly is the best for those situations. After inserting the needle into the vein the butterfly can be left to recline on their arm, staying somewhat stable even if they move.
The tubing between the needle and the collection tube or syringe will lessen the pressure on the tender veins, allowing for less vein collapse and better quality of blood.
Use a 23 gauge as their veins are usually small. There are occasions when you might find a bigger vein but generally the 23 gauge is used.
The syringe method may at times be a better choice depending on the situation, so bear that in mind.
2. Use for the elderly
Saggy skin, rolling veins, collapsible veins, and hematomas are characteristic of the elderly. Using the evacuated tube system is not recommended, unless the vein is of good quality and won’t collapse. The butterfly or syringe is the preferred method.
Whether attempting to draw blood from the antecubital fossa, the forearm, or the back of the hand, the butterfly is the better choice. It is especially good for small and rolling veins at the back of the hand, which can sometimes prove difficult to stick.
Older patients’ veins are weaker and susceptible to collapsing and blowing (blown veins). The tubing of the butterfly system lessens the pressure coming from the tube vial or syringe on the veins, preventing collapsing and maintaining the integrity of the sample.
A syringe, though, is a better choice for deep veins in the antecubital fossa area as the butterfly needle is short and may not reach deep veins effectively.
At hospital settings, syringes are used often for drawing blood from the elderly, however, using the butterfly in some situations may prove more efficient.
3. Use for difficult sticks/veins
Another critical area for using the winged infusion set, is for difficult sticks or veins. This includes children, adults, the elderly, as well as, small/thing thins, rolling veins, fragile veins, and veins that have been hardened by drug use.
The idea here is that the butterfly needle’s small size and short length can be very helpful in getting blood drawn from these veins. The flexibility and control it gives make it easier to obtain blood in spite of the difficulty that may be present.
You don’t have many chances when drawing blood from a difficult person, so it is important that you get blood the first time, if not, the second. Using the butterfly needle will increase your chances.
The butterfly is for superficial veins, so any vein that is deep, you will want to use the syringe method instead.
4. Good for those with needle phobia
There are many individuals who are afraid of needles and something about the butterfly seem to make them more relaxed and able to do the blood test.
Part of it, is the size of the butterfly needle and the butterfly system in general. The butterfly needle is short and the mechanism is small. For some reason, that eases the nerves of these people, making them less apprehensive and more willing to go through the process.
The evacuated tube system or the syringe method is huge in their eyes. The length of the needle and the size of the apparatus are what scare most people. Many times, while attempting to draw blood a person will tell me how big (length & size) the needle is and ask if there is a smaller one or sometimes they will even mention using the butterfly instead.
Evacuated tube and syringe needles come in 1, 1 1/2, and 2 inches normally. The standard butterfly needle is 3/4 inch long. That is a big difference in length for those who are afraid of needles.
Using a butterfly needle to draw blood from a person with good veins (because of needle phobia) may not always be viable but there are occasions when it may be needed.
5. Use when other methods fail
As you would already know, the butterfly is not the first method to use when performing venipuncture. Of course, there are cases when the butterfly will be the best choice from the start, but in general, it is not the first choice.
Because it is easy to use and control, it can be a temptation to use it often when other methods would take precedence.
In fact, some labs, doctors’ office, or hospitals limit the use of butterflies to none at all, while others allow its use to when it’s needed or even give some freedom to use it whenever.
That being said, there are some occasions when either the evacuated tube system or the syringe may fail at venipuncture but the butterfly will save you.
Other Advantages of the Butterfly System
- Here are some more advantages to using the butterfly needle:
- Flash when needle enters the vein. When the needle enters a vein there is a visible flash that lets you know that you have hit your mark 😀
- Better angle insertion.
- Can be used on almost any superficial surface.
- Said to be less painful than other methods.
- Safety mechanism. After the needle is removed from the vein, the safety mechanism is activated, which insulates the needle preventing needle stick injuries.
Disadvantages of the Butterfly Needle
- Can be difficult to insert into the vein properly due to the short length of the needle or apparatus.
- Can be easily pulled back from the vein (due to its short length). And in that case may require a second venipuncture attempt.
- The safety button or mechanism can be pushed or activated before indented. The button is near your fingers and pushing it accidentally while performing blood draw is a possibility.
- More expensive to purchase.
- Tubing can reduce filling of tubes due to loss of vacuum. While the tubing can lessen the pressure exerted on veins, it reduces how much blood can be collected.
- Tubing can reduce the effectiveness of a syringe if the patient’s blood flow is slow.
The Butterfly Vs the Syringe Method
As I have already mentioned above, the butterfly and the syringe method overlap in their use. Sometimes, where you will use a syringe, you can use a butterfly and vice versa.
Follow your institutional policies surrounding the use of syringes and butterflies.
Both butterfly and syringe have their own advantages. While you can use a syringe to draw blood from the back of the hand, using the butterfly can be a lot easier and also better suited in some instances.
Also, there are times when it’s better to use a syringe instead of a butterfly like when a person blood is slow (rate of flow).
Butterflies are good with infants and babies but the syringe can also get the job done. It’s going to depend on your place of work and the method that is best suited for the task at hand.
I wrote an article about the syringe method, highlighting its advantages and disadvantages. Click here to go read it.