Syringe and Needle
Syringes and needles are sterile devices used to inject solutions into or withdraw secretions from the body. The syringe is a calibrated glass or plastic cylinder with a plunger at one and an opening to which the needle attaches.
This method is used to administer drugs when a small amount of fluid is to be injected, the patient is unable to take the drug orally, or intestinal secretions destroy the drug. It is also to withdraw various types of bodily fluids, most commonly blood.
There are different types and sizes of syringes used for a variety of purposes. Syringe sizes may vary from0.25 ml to 450 ml, and can be made from glass or assorted plastics. Latex-free syringes eliminate the exposure of the health care professional and the patient to an allergen to which he or she may be sensitive. The most common type of syringe is the piston syringe. The pen, cartridge, and dispensing syringes are also extensively used.
A syringe consists of a hollow barrel with a piston at one end and a nozzle at the other end that connects to a needle. Other syringes have a needle already attached. These devices are often used for subcutaneous injections of insulin and are single-use (i.e., disposable). Syringes have markings etched or printed on their sides, showing the graduations (i.e., in milliliters) for accurate dispensing of drugs or removal of body fluids. Cartridge syringes are for multiple use, and are often sold in kits where a prefilled drug cartridge with a needle is inserted into the piston syringe. Syringes may also have antineedlestick features, as well as positive stops that prevent accidental pullouts.
There are three types of nozzles:
- Luer-lock, which locks the needle onto the nozzle of the syringe.
- Slip tip, which secures the needle by compressing the hub onto the syringe nozzle.
- Eccentric, which secures with a connection that is almost flush with the side of the syringe.
The hypodermic needle is a hollow, metal tube, usually made of stainless steel and sharpened at one end. It has a female connector end that fits into the male connector of a syringe or intravascular administration set.
The size of the diameter of the needle ranges from the largest gauge (13) to the smallest (27). The needle's length extends to 3.5 inches (8 cm) for the 13 gauge, and from 0.25–1 inch (0.6-2.5 cm) for the 27 gauge. The needle consists of a hub with a female connector at one end—that connects to a syringe—to the other end, where the bevel is located. The bevel is a flat aperture on one side of a needle's tip.
Needles are almost always disposable, but reusable ones are available for home use by a single patient.
Syringes and needles are used for injecting or withdrawing fluids from a patient. The most common procedure for removing fluids from a patient is the venipuncture, or blood drawing. In this procedure, the syringe and appropriate needle are used with a vacutainer, which is used to collect the blood as it is drawn. The syringe and needle can be left in place while the vacutainer is changed, allowing for multiple samples to be drawn.
Fluids can be injected into a patient by intradermal injection, subcutaneous injection, intramuscular injection, or Z-track injection. In all types of injections, the size of syringe should be chosen based on the amount of fluid being delivered, and the gauge and length of needle should be chosen based on the size of the patient and the type of medication. A needle with a larger gauge may be chosen for drawing up the medication into the syringe, and a smaller gauge needle will replace the previous one for injection into the patient. In all injections, proper procedures for infection control should be strictly followed.
Syringes and needles are normally sterile products and should be stored in appropriate containers. Care should be taken prior to using them. One should ensure that the needles are not blunt and that the packets are not torn; this would expose the contents to air and allow contamination by microorganisms.
Health care team roles
Used syringes and needles should be disposed of quickly in appropriate containers.
If a needlestick injury occurs, it is important that it is reported immediately and that proper treatment is administered to the injured person.
Those responsible for training should ensure staff is skilled at up-to-date methods of aseptic technique and correct handling/use of syringes and needles.
Teaching the correct use of and syringes and needles, as well as their disposal, is important to protect medical staff and patients from needlestick injuries and contamination from blood-borne infections. Presently, some of the more serious infections are human immunodeficiency virus (HIV), hepatitis B (HBV), and hepatitis C (HCV).
The staff should be aware of current methods of infection prevention.
Altman, Gaylene Bouska, Patricia Buchsel, and Valerie Coxon, eds. Fundamental and Advanced Nursing Skills. Albany, NY: Delmar, 2000.
American College of Allergy, Asthma, and Immunology. Latex allergy home page. <http://allergy.mcg.edu/advice/latex.html>.
Centers for Disease Control. How to protect yourself from needlestick injuries. DHHS 9NIOSH publication No. 2000-135. NIOSH. 2001. <http://www.cdc.gov/niosh/homepage.html>.
Food and Drug Administration. Guidance on the content of premarket notification [510(K)] submissions for piston syringes. 2001. <http://www.fda.gov/cdrh/ode/odegr821.html>.
Margaret A Stockley, R.N.
Bevel—The flat aperture on one side of a needle at the tip.
Piston—The plunger that slides up and down the inside barrel of a syringe.
Sterile—Free from living microorganisms.
Subcutaneous—Beneath the skin.