A butterfly needle, more formally known as a winged infusion set, is a specialized device designed for venipuncture procedures like drawing blood or administering intravenous fluids. The device gets its common name from the two small, flexible plastic wings attached to the base of a short, thin needle. These wings provide a stable surface for gripping and manipulating the needle, which is helpful when accessing small, rolling, or fragile veins. The needle is connected to transparent tubing that ends in a connector, allowing attachment to a vacuum tube holder or an IV line. This design is often preferred for pediatric and geriatric patients, or those with difficult venous access, as the smaller needle size and increased control minimize trauma and discomfort.
Preparing the Equipment and Site
All necessary supplies must be gathered before beginning the procedure. This includes the butterfly needle assembly, blood collection tubes, antiseptic wipes, a tourniquet, gauze, and a puncture-resistant sharps container. The butterfly needle must be connected to its vacuum tube holder or Luer lock adapter before venipuncture begins, ensuring the system is ready to collect blood immediately upon successful vein entry.
Site selection is important, with veins in the forearm or the back of the hand being common targets. Once a suitable vein is identified, the tourniquet is applied two to four inches above the insertion site to engorge the vein, making it more prominent and easier to access. The site must then be thoroughly cleaned using a circular motion with an antiseptic wipe, starting at the center and moving outward. Allowing the skin to air-dry completely prevents contamination and avoids a stinging sensation when the needle is inserted.
Mastering the Grip for Control
The most common technique involves grasping the textured wings of the butterfly set between the dominant hand’s thumb and index finger, folding them upward into a slight pinch. This allows the operator to manipulate the needle with accuracy, keeping the bevel facing upward throughout the approach. Holding the set close to the needle hub, rather than near the tubing, provides better maneuverability and reduces the chance of accidental movement during insertion.
The non-dominant hand anchors the vein below the intended puncture site. Applying a gentle downward stretch to the skin helps prevent the vein from rolling or shifting away from the needle upon contact. Maintaining this steady grip and anchoring pressure ensures that the needle’s trajectory remains stable as it pierces the skin.
Step-by-Step Insertion and Stabilization
With the bevel facing up, the needle should be aligned with the direction of the vein and inserted at a shallow angle, between 10 and 15 degrees. This low angle helps to access superficial veins without passing completely through the vessel. A smooth, swift motion is recommended to pierce the skin and the vessel wall in one controlled action, which reduces patient discomfort and the risk of the vein collapsing.
Successful entry into the vein is confirmed by the appearance of a small amount of blood, known as “flashback,” visible in the transparent tubing of the butterfly set. Once flashback is seen, the needle angle should be slightly lowered and advanced an extra millimeter or two to ensure the entire bevel is securely within the vein lumen.
The wings of the butterfly set can then be gently released and taped flat against the skin to stabilize the needle and prevent any shifting or dislodgement during the collection process. This stabilization is especially important when multiple collection tubes are required.
Safe Collection and Removal Practices
After stabilization, the blood collection process begins by inserting the first vacuum tube into the holder and allowing it to fill completely. If multiple tubes are needed, they should be exchanged smoothly without disturbing the needle’s position in the vein, stabilizing the holder with one hand while swapping tubes with the other. The tourniquet must be released immediately before the final tube is finished filling or before the needle is withdrawn, preventing unnecessary pressure buildup in the vein.
Once the collection is complete, the needle is removed from the vein in one smooth, continuous motion. Immediately upon withdrawal, firm pressure must be applied to the puncture site with a clean piece of gauze. The entire butterfly assembly must be immediately discarded into an approved sharps container. Many modern butterfly needles feature a safety mechanism that must be activated during removal to shield the sharp point, protecting the user from accidental needlestick injuries.