Safety with Needles and Syringes

While it is unlikely that a technician in a retail setting will need to use needles and syringes much, they are a part of the daily life of most hospital technicians. It is important to learn the safety procedures associated with needles to avoid injury or worse for you and your patient.

What's the Difference Between a Needle and a Syringe
While this may seem trivial, many without a lot of experience in the field don't realize that there is a difference between the two. The needle is the metal part that actually pierces the skin and through which the medication flows to reach the intramuscular or subcutaneous injection site. It is often detachable from the syringe to allow for IV pushes and such. There are three main parts of a needle: the hub, where a technician would place a filter if needed; the shaft, the actual body of the needle; and the bevel, the cut of the needle that allows a sharp, piercing point. The lumen (as seen below) is the inside of the shaft, where the medication flows.

The syringe is everything else. The main parts are the tip, where the needle screws into; the barrel, where the medication is stored and measured; and the plunger, which allows the medication to be drawn into or pushed out of the barrel. Below, the barrel is shown filled with a purple liquid and is calibrated along the side. The liquid inside the barrel should occupy between 1/2 and 3/4 of the syringe, to ensure accurate measurement.

Some syringes, like oral dosage syringes that are commonly dispensed with children's medications, do not have the capacity to accept a needle.

Needle and Syringe Sizing
Syringes are measured by their fluid capacity in milliliters. As mentioned above, the amount of fluid in the syringe should occupy between 1/2 and 3/4 of the available space inside of the syringe.

Needles are measured by gauge. The higher the gauge, the smaller the needle. The largest needles that are routinely used for medical purposes are around 13 gauge, while the smallest are as small as 30 gauge. The following image will give you a better idea of a difference of just 10.

When injecting into the patient rather than an IV bag, the smallest gauge that the medication can easily flow through should be used (for patient comfort). Some medications, like testosterone cyprionate, are extremely viscous and require a large needle for injection.

Ensuring Sterility and Patient Safety
Packaged needles and syringes are guaranteed sterile so long as the packaging is 100% intact. If it is not, the device should not be used. For pre-packaged medications, like the unit-of-use medroxyprogesterone suspension for injection, the package should not be opened until it is time for the injection.

Never tough the needle or any internal part of the syringe (like the face of the plunger or inside of the barrel) for any reason.

When withdrawing medication from an ampule, a 5-micron filter should be placed in the hub of hte needle to prevent shards of glass from entering the needle and then being re-injected into the patient. Even the tiniest pieces of glass in the bloodstream can cause damage, which can result in uncontrollable internal bleeding.

Items for IV admixture should be opened inside a laminar airflow hood and before beginning, a tech should was their hands. All materials should be placed within the sterile zone of the laminar airflow hood and all surfaces which will come in contact with the needle should be sterilized appropriately with 70% isopropyl alcohol and allowed to dry. Air bubbles in the syringe should be removed by inverting the syringe (needle facing up) and tapping while gently pressing on the plunger.

Disposal of Used Needles
Needles should be disposed of in an appropriate sharps container. Cytotoxic materials usually have to be disposed of in their own sharps container, so be careful. Needles should be dropped into the container needle facing down without recapping the needle. Recapping the needle increases the risk of sticking yourself with the needle, resulting in exposure to unnecessary, or possibly even cytotoxic materials or possible exposure to a patient's blood-borne pathogen such as hepatitis or HIV. I cannot stress this enough do not recap the needle. With pen needles, sharps containers usually come with a special device to remove the needle and drop it into the container. The pen device can then be returned to storage. If not, the needle should be carefully removed from the pen and dropped into the sharps container. The pen should be returned to storage without a needle in place. Needles should never be reused to ensure sterility and comfort (they get duller with each penetration of the skin).

Resources
Anesthesia- Equipment. Web. 17 Jul 2011. <http://emprocedures.com/anesthesia/equipment.htm>.

"Hypodermic Syringe." Syringes/Needles. Web. 17 Jul 2011. <http://www.oocities.org/medical_supplies_equipment/needles-syringes.html>.

The Pharmaceuticals and Compounding Laboratory. Web. 17 Jul 2011. <http://pharmlabs.unc.edu/labs/parenterals/syringes.htm>.