Syringe needle

Types

Syringe needles are useful in many medical operations, from routine shots to complex surgeries. They come in various sizes, shapes, and materials, each suitable for different medical requirements, of which it's vital to understand all the diversity due to the multiple applications.

Some common types include:

• Regular Cutter Needles

  Standard hypodermic needles are one of the most widely used medical syringe needle configurations. These needles are commonly used for giving intramuscular, subcutaneous, and intravenous medicines. They come in differing widths, known as gauze, and differing lengths, appropriate for differing clinical applications. In general, the shorter the hypodermic needle, the smaller its gauge, and the greater the length, the smaller its gauge. Therefore, a 30 gauge × 1.5 needle will be bigger than a 21 gauge × 1.5 needle in length, though, because it has longer length; it is better for precise procedures, such as intravenous injections, while the 21 gauge needle being better at larger volume injections.

• Insulin Needles

  Insulin needles are meant for use in diabetes patients who must self-inject insulin frequently. These needles are smaller in their gauge, which makes them less scary to patients who will be injecting themselves often. Insulin syringes mostly come with needles of 6mm, 8mm, and 12mm lengths but be aware that patient's requirements will determine which one to use. Most of the time, the insulin syringe used will be a 28-gauge needle or finer, meaning that the needle will be more than 0.02mm but less than 0.03mm in width. This greatly minimizes discomfort and facilitates accurate insulin dosage.

• Blood Donation Needles

  Blood collection for transfusions and testing is performed using thick-bore needles. For adult blood draws, the most common gauge sizes are 18 and 20; hence, larger needles allow blood to flow quickly into the syringe with less chance of the blood cells rupturing due to pressure. Because large needles are less comfortable and offer a risk of injury, health care personnel selectively and professionally choose them for procedures requiring a larger volume of fluid transfer or injection.

• Sewing Needles

  Surgical sewing needles, also called hypodermic needles, are used in surgical procedures where accuracy is essential. They are also called hypodermic needles and come in varying lengths and gauges, depending on the operation being performed, the tissues involved, and the surgeon's preference.

Material & Durability

The material a syringe and needle is made of plays a vital role in the durability, biocompatibility, and sterility of medical devices. Therefore, the common materials that syringe needles are made out of are as follow.

• Stainless Steel

  As a commonly used needle material, it's highly durable, corrosion-resistant, and easy to sterilize. Most hypodermic needles, insulin needles, and surgical needles are made from stainless steel. Because of its strength, stainless steel can be manufactured into very fine needles that are sharp enough for precise medical procedures.

• Plastic

  Syringes are made of plastic, usually polycarbonate, for disposability, transparency, and durability. Plastic syringes are commonly seen in primary health care settings where sterility can be compromised. The rigidity of polycarbonate syringes also allows for accurate measurements to be seen on the syringe because this material does not deform the syringe.

• Rubber

  Rubber is mainly used for the plunger and the needle guard to keep the needle safe and ensure an airtight seal when the needle is pulled. Most rubber used in medical syringes is natural rubber or latex, though many also use butyric acrylonitrile elastomer. For butyric acrylonitrile, it is used in people known to be allergic to natural rubber due to allergic reactions that cause them discomfort.

• Glass

  A syringe is typically made from borosilicate glass because of its ability to resist thermal and chemical destruction. This long-lasting material is non-porous, which does not allow bacteria to penetrate; thus, it maintains sterility more effectively than plastic syringes. However, due to their composition and construction, glass syringes are more convenient for medical applications that need a high degree of precision, such as injecting medications or performing surgery.

Applications

Hypodermic needles have multiple clinical applications based on their type, size, and composition. These have been listed out with the kind of procedure for which the needles are best suited.

• Intradermal Injections

  Intradermal injections inject the medicament into the dermal layer for tuberculin skin tests and allergy screening. 1–2 ml syringes have hypodermic needles with short, fine needles, usually 26–30 gauge, which are ideal for this injection. Intradermal injections are performed using short needles (2-5 cm) in intracutaneous injections. An intradermal needle is specialized for intradermal injections, as it is a small gauge, approximately 26-30 gauge, and a short length of 1-5 mm. Intradermal medical syringes allow drugs to be accurately delivered to the desired skin layer for quicker absorption and localized effects.

• Subcutaneous Injections

  Subcutaneous injections are used in drug delivery in the dermis of the skin, which is the predicted depth in order to achieve a slow absorption rate into the bloodstream. Common medicines given this way are insulin and vaccines, mostly employing 25-27 gauge needles and 1-2ml syringes of 5/8 to 1 inch in length. Such needles are long enough to reach the intradermal layer without penetrating deep into the body.

• Intramuscular Injections

  For intramuscular, intravenous, and intra-dermal injections, the medication is injected directly into the muscle tissue, blood vessel, and dermal layer, respectively. Common drugs administered this way include vaccines and corticosteroids, using a 21- to 23-gauge needle of 1-2 ml in length. These needles are the best for taking blood, as they can easily pierce skin tissue.

• Intravenous Injections

  Intravenous injections deliver medicine directly into a person's bloodstream through a vein. IV injections are given using hypodermic needles to deliver fluids to a vein. The most typical IV catheters employ needles ranging from 18 to 25 gauge, with longer needles gauged at 1-1.5 inch long. Gauges 18-20 are primarily used for blood transfusions and fluid replacement, while 22-25 are for drugs that need to be pushed quickly and for smaller veins.

• Surgical Procedures

  Invasive medical procedures are done using sewing needles. Sewing needles come in different bore sizes, lengths, and materials to sew internal organs, suturing soft tissue, and injecting local anesthetics. Most hypodermic needles for surgery are round bodied and made of stainless steel for rigidity and sharpness. Stainless steel provides durability, flexibility, and a smooth, sharp cutting edge, which is preferred for surgical needles.

How To Choose

When syringes and needles are needed for several medical purposes, some factors are best considered regarding the health of the user and the quality of health care they receive. Needle size, syringe volume, and one-time vs. multiple uses are three critically important factors to consider, along with quality manufacturing.

Guidelines for choosing appropriate medical syringes and needles include:

• Procedure requirements

  One has to evaluate the operation and therapy to be given to choose the proper syringe and needle. A thicker needle will be graded in blood draws or intramuscular injections, while finer will do in intradermal injections. Invasiveness also requires consideration; for example, drug infusions need a larger volume syringe and an appropriate needle.

• Syringe volume

  Medically, syringes come in different volumetric capacities, ranging in size from 1 milliliter to 60 milliliters. A smaller syringe, like the 1 ml, will be suitable where accuracy is highly desired, such as in intravenous medication. However, larger syringes are suitable for irrigation and sampling, where volume matters the most.

• Ga of needles

  Generally, needles with higher gauge numbers are finer than those with lower number gauges. Therefore, finer needles are used in less invasive procedures such as intradental injections, while in drugs, especially those with thicker solution particles or blood products, larger needles are required.

• Single-use vs. re-use

  Some syringes and needles are meant for a single use, while others can be re-used several times, provided their sterilization is guaranteed. Most culture media and reagents are delivered through multi-use hypodermics and needles, whereas everything involving medications given to patients must be through a one-time use to avoid cross-contamination.

• Quality and Sterility

  One consideration in choosing syringes and needles is quality, which extends to sterility. Since the items are expected to be sterile, only those from reputable manufacturers, certified, have quality control consistency, especially for sterile medical devices, must be considered.

Q & A

Q1: What factors determine the appropriate needle gauge for a procedure?

A1: The needle gauge depends on the injection type, drug viscosity, and patient condition. Larger gauges (lower numbers) are for intramuscular or intravenous injections, while smaller ones suit subcutaneous or intradermal injections. For blood draws, larger needles ensure faster collection. Additionally, thicker medications require a larger needle to prevent clogging, while smaller needles are more comfortable for routine injections.

Q2: Why is stainless steel preferred for syringe needles?

A2: Stainless steel is strong, rust-resistant, and easy to sterilize. It forms very sharp edges, ensuring better patient comfort. Also, because of its rigidity, it is used in syringes and needles, which do not have to be deformed for various surgical procedures and injections.

Q3: Why are glass syringes less commonly used than plastic ones?

A3: Glass syringes, although more sterile than plastic, are less frequently used because they are more breakable. They are still used in operations needing higher accuracy and re-immersion because they can be cleaned. Moreover, because of materials' sterilization retention, these syringes are typically found in hospitals, surgeries, and other health facilities.

Q4: How can one ensure proper sterility when reusing needles?

A4: Proper sterilization of a hypodermic needle means immersing it in an appropriate autoclave or chemical sterilizer solution between usages to kill all microorganisms. The nurse or doctor is responsible for making sure this happens so that when the needle is used again, it does not cause infections or disease transmission.

Q5: What are lubrication syringes used for?

A5: Lubrication syringes mostly used in medicine, dentistry, and surgery to inject lube in inaccessible areas around body cavities where lube is needed to ease internal examination, manipulation, or exploration. For instance, it is used for lubricating rectally or vaginally and in some surgical openings to ease examinations or procedures.