Syringe | |
---|---|
Classification | Medical device |
Industry | Healthcare |
Application | Injection |
Inventor | Charles Pravaz (screw) Alexander Wood (plunger) |
Invented | 1853 |
A syringe is a simple reciprocating pump consisting of a plunger (though in modern syringes, it is actually a piston) that fits tightly within a cylindrical tube called a barrel. The plunger can be linearly pulled and pushed along the inside of the tube, allowing the syringe to take in and expel liquid or gas through a discharge orifice at the front (open) end of the tube. The open end of the syringe may be fitted with a hypodermic needle, a nozzle or tubing to direct the flow into and out of the barrel. Syringes are frequently used in clinical medicine to administer injections, infuse intravenous therapy into the bloodstream, apply compounds such as glue or lubricant, and draw/measure liquids. There are also prefilled syringes (disposable syringes marketed with liquid inside).
The word "syringe" is derived from the Greek σῦριγξ ( syrinx , meaning "Pan flute", "tube").
Sectors in the syringe and needle market include disposable and safety syringes, injection pens, needleless injectors, insulin pumps, and specialty needles. [2] Hypodermic syringes are used with hypodermic needles to inject liquid or gases into body tissues, or to remove from the body. Injecting of air into a blood vessel is hazardous, as it may cause an air embolism; preventing embolisms by removing air from the syringe is one of the reasons for the familiar image of holding a hypodermic syringe pointing upward, tapping it, and expelling a small amount of liquid before an injection into the bloodstream.
The barrel of a syringe is made of plastic or glass, usually has graduated marks indicating the volume of fluid in the syringe, and is nearly always transparent. Glass syringes may be sterilized in an autoclave. Plastic syringes can be constructed as either two-part or three-part designs. A three-part syringe contains a plastic plunger/piston with a rubber tip to create a seal between the piston and the barrel, where a two-part syringe is manufactured to create a perfect fit between the plastic plunger and the barrel to create the seal without the need for a separate synthetic rubber piston. Two-part syringes have been traditionally used in European countries to prevent introduction of additional materials such as silicone oil needed for lubricating three-part plungers. [3] Most modern medical syringes are plastic because they are cheap enough to dispose of after being used only once, reducing the risk of spreading blood-borne diseases. Reuse of needles and syringes has caused spread of diseases, especially HIV and hepatitis, among intravenous drug users. Syringes are also commonly reused by diabetics, as they can go through several in a day with multiple daily insulin injections, which becomes an affordability issue for many. Even though the syringe and needle are only used by a single person, this practice is still unsafe as it can introduce bacteria from the skin into the bloodstream and cause serious and sometimes lethal infections. [4] In medical settings, single-use needles and syringes effectively reduce the risk of cross-contamination. [5]
Medical syringes are sometimes used without a needle for orally administering liquid medicines to young children or animals, or milk to small young animals, because the dose can be measured accurately and it is easier to squirt the medicine into the subject's mouth instead of coaxing the subject to drink out of a measuring spoon.
Syringes come with a number of designs for the area in which the blade locks to the syringe body. Perhaps the most well known of these is the Luer lock, which simply twists the two together.
Bodies featuring a small, plain connection are known as slip tips and are useful for when the syringe is being connected to something not featuring a screw lock mechanism.
Similar to this is the catheter tip, which is essentially a slip tip but longer and tapered, making it good for pushing into things where there the plastic taper can form a tight seal. These can also be used for rinsing out wounds or large abscesses in veterinary use.
There is also an eccentric tip, where the nozzle at the end of the syringe is not in the centre of the syringe but at the side. This causes the blade attached to the syringe to lie almost in line with the walls of the syringe itself and they are used when the blade needs to get very close to parallel with the skin (when injecting into a surface vein or artery for example).
Syringes for insulin users are designed for standard U-100 insulin. The dilution of insulin is such that 1 mL of insulin fluid has 100 standard "units" of insulin. [6] Since insulin vials are typically 10 mL, each vial has 1000 units.
Insulin syringes are made specifically for self injections and have friendly features:
U-100 syringe sizes and markings | |
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1cc (1 mL) Syringe | |
Holds maximum: | 100 units [10] |
Numbered in: | 10 unit increments [10] |
Smallest line measures 2 units: [11] | BD [10] ReliOn [12] Monoject [13] (all but 31 gauge needle) |
Smallest line measures 1 unit: | Easy Touch [14] Precision Sure Dose [13] |
1/2cc (0.5 mL) Syringe | |
Holds maximum: | 50 units [15] |
Numbered in: | 10 unit increments [15] |
Smallest line measures 1 unit: [11] | BD [15] Precision Sure Dose [13] Ulti-Care [13] [16] Easy Touch [17] ReliOn [12] Monoject [13] |
3/10cc (0.3 mL) Syringe | |
Holds maximum: | 30 units [18] |
Numbered in: | 5 unit increments [18] |
Smallest line measures 1 unit: [11] | BD Micro Fine [13] BD Ultra Fine [13] [18] (standard length only) Monoject [13] Easy Touch [19] UltiCare [13] |
Half-unit scale 3/10cc (0.3 mL) Syringe [20] | |
Holds maximum: | 30 units [18] |
Numbered in: | 5 unit increments [18] |
Smallest line measures 1/2 unit: | BD Ultra Fine II (short) [13] [18] ReliOn [12] [13] |
There are needle syringes designed to reload from a built-in tank (container) after each injection, so they can make several or many injections on a filling. These are not used much in human medicine because of the risk of cross-infection via the needle. An exception is the personal insulin autoinjector used by diabetic patients and in dual-chambered syringe designs intended to deliver a prefilled saline flush solution after the medication. [21]
Venom extraction syringes are different from standard syringes, because they usually do not puncture the wound. The most common types have a plastic nozzle which is placed over the affected area, and then the syringe piston is pulled back, creating a vacuum that allegedly sucks out the venom. Attempts to treat snakebites in this way are specifically advised against, as they are ineffective and can cause additional injury. [22]
Syringes of this type are sometimes used for extracting human botfly larvae from the skin. [23]
An oral syringe is a measuring instrument used to accurately measure doses of liquid medication, expressed in millilitres (mL). They do not have threaded tips, because no needle or other device needs to be screwed onto them. The contents are simply squirted or sucked from the syringe directly into the mouth of the person or animal.
Oral syringes are available in various sizes, from 1–10 mL and larger. An oral syringe is typically purple in colour to distinguish it from a standard injection syringe with a luer tip. [24] The sizes most commonly used are 1 mL, 2.5 mL, 3 mL, 5 mL and 10 mL. [25]
A dental syringe is used by dentists for the injection of an anesthetic. [26] It consists of a breech-loading syringe fitted with a sealed cartridge containing an anesthetic solution.
In 1928, Bayer Dental developed, coined and produced a sealed cartridge system under the registered trademark Carpule®. The current trademark owner is Kulzer Dental GmbH.
The carpules have long been reserved for anesthetic products for dental use. It is practically a bottomless flask. The latter is replaced by an elastomer plug that can slide in the body of the cartridge. This plug will be pushed by the plunger of the syringe. The neck is closed with a rubber cap. The dentist places the cartridge directly into a stainless steel syringe, with a double-pointed (single-use) needle. The tip placed on the cartridge side punctures the capsule and the piston will push the product. There is therefore no contact between the product and the ambient air during use.
The ancillary tool (generally part of a dental engine) used to supply water, compressed air or mist (formed by combination of water and compressed air) to the oral cavity for the purpose of irrigation (cleaning debris away from the area the dentist is working on), is also referred to as a dental syringe or a dental irrigation nozzle.
A 3-way syringe/nozzle has separate internal channels supplying air, water or a mist created by combining the pressurized air with the waterflow. The syringe tip can be separated from the main body and replaced when necessary.
In the UK and Ireland, manually operated hand syringes are used to inject lidocaine into patients' gums. [27] [28] [26]
A dose-sparing syringe is one which minimises the amount of liquid remaining in the barrel after the plunger has been depressed. These syringes feature a combined needle and syringe, and a protrusion on the face of the plunger to expel liquid from the needle hub. Such syringes were particularly popular during the COVID-19 pandemic as vaccines were in short supply. [29]
In some jurisdictions, the sale or possession of hypodermic syringes may be controlled or prohibited without a prescription, [30] due to its potential use with illegal intravenous drugs. [31]
The syringe has many non-medical applications.
Medical-grade disposable hypodermic syringes are often used in research laboratories for convenience and low cost. Another application is to use the needle tip to add liquids to very confined spaces, such as washing out some scientific apparatus. They are often used for measuring and transferring solvents and reagents where a high precision is not required. Alternatively, microliter syringes can be used to measure and dose chemicals very precisely by using a small diameter capillary as the syringe barrel.
The polyethylene construction of these disposable syringes usually makes them rather chemically resistant. There is, however, a risk of the contents of the syringes leaching plasticizers from the syringe material. Non-disposable glass syringes may be preferred where this is a problem. Glass syringes may also be preferred where a very high degree of precision is important (i.e. quantitative chemical analysis), because their engineering tolerances are lower and the plungers move more smoothly. In these applications, the transfer of pathogens is usually not an issue.
Used with a long needle or cannula, syringes are also useful for transferring fluids through rubber septa when atmospheric oxygen or moisture are being excluded. Examples include the transfer of air-sensitive or pyrophoric reagents such as phenylmagnesium bromide and n-butyllithium respectively. Glass syringes are also used to inject small samples for gas chromatography (1 μl) and mass spectrometry (10 μl). Syringe drivers may be used with the syringe as well.
Some culinary uses of syringes are injecting liquids (such as gravy) into other foods, or for the manufacture of some candies.
Syringes may also be used when cooking meat to enhance flavor and texture by injecting juices inside the meat, and in baking to inject filling inside a pastry. It is common for these syringes to be made of stainless steel components, including the barrel. Such facilitates easy disassembly and cleaning.
Syringes are used to refill ink cartridges with ink in fountain pens.
Common workshop applications include injecting glue into tight spots to repair joints where disassembly is impractical or impossible; and injecting lubricants onto working surfaces without spilling.
Sometimes a large hypodermic syringe is used without a needle for very small baby mammals to suckle from in artificial rearing.
Historically, large pumps that use reciprocating motion to pump water were referred to as syringes. Pumps of this type were used as early firefighting equipment.
There are fountain syringes where the liquid is in a bag or can and goes to the nozzle via a pipe. In earlier times, clyster syringes were used for that purpose.
Loose snus is often applied using modified syringes. The nozzle is removed so the opening is the width of the chamber. The snus can be packed tightly into the chamber and plunged into the upper lip. Syringes, called portioners, are also manufactured for this particular purpose.
Intensive insulin therapy or flexible insulin therapy is a therapeutic regimen for diabetes mellitus treatment. This newer approach contrasts with conventional insulin therapy. Rather than minimize the number of insulin injections per day, the intensive approach favors flexible meal times with variable carbohydrate as well as flexible physical activities. The trade-off is the increase from 2 or 3 injections per day to 4 or more injections per day, which was considered "intensive" relative to the older approach. In North America in 2004, many endocrinologists prefer the term "flexible insulin therapy" (FIT) to "intensive therapy" and use it to refer to any method of replacing insulin that attempts to mimic the pattern of small continuous basal insulin secretion of a working pancreas combined with larger insulin secretions at mealtimes. The semantic distinction reflects changing treatment.
A pipette is a type of laboratory tool commonly used in chemistry and biology to transport a measured volume of liquid, often as a media dispenser. Pipettes come in several designs for various purposes with differing levels of accuracy and precision, from single piece glass pipettes to more complex adjustable or electronic pipettes. Many pipette types work by creating a partial vacuum above the liquid-holding chamber and selectively releasing this vacuum to draw up and dispense liquid. Measurement accuracy varies greatly depending on the instrument.
An autoinjector is a medical device for injection of a premeasured dose of a particular drug. Most autoinjectors are one-use, disposable, spring-loaded syringes. By design, autoinjectors are easy to use and are intended for self-administration by patients, administration by untrained personnel, or easy use by healthcare professionals; they can also overcome the hesitation associated with self-administration using a needle. The site of injection depends on the drug, but it typically is administered into the thigh or the buttocks.
A hypodermic needle, one of a category of medical tools which enter the skin, called sharps, is a very thin, hollow tube with one sharp tip. It is commonly used with a syringe, a hand-operated device with a plunger, to inject substances into the body or extract fluids from the body. Large-bore hypodermic intervention is especially useful in catastrophic blood loss or treating shock.
A cannula is a tube that can be inserted into the body, often for the delivery or removal of fluid or for the gathering of samples. In simple terms, a cannula can surround the inner or outer surfaces of a trocar needle thus extending the effective needle length by at least half the length of the original needle. Its size mainly ranges from 14 to 26 gauge. Different-sized cannula have different colours as coded.
Subcutaneous administration is the insertion of medications beneath the skin either by injection or infusion.
A Fuel pump is a component used in many liquid-fuelled engines to transfer the fuel from the fuel tank to the device where it is mixed with the intake air.
An injection is the act of administering a liquid, especially a drug, into a person's body using a needle and a syringe. An injection is considered a form of parenteral drug administration; it does not involve absorption in the digestive tract. This allows the medication to be absorbed more rapidly and avoid the first pass effect. There are many types of injection, which are generally named after the body tissue the injection is administered into. This includes common injections such as subcutaneous, intramuscular, and intravenous injections, as well as less common injections such as epidural, intraperitoneal, intraosseous, intracardiac, intraarticular, and intracavernous injections.
A jet injector is a type of medical injecting syringe device used for a method of drug delivery known as jet injection. A narrow, high-pressure stream of liquid is made to penetrate the outermost layer of the skin to deliver medication to targeted underlying tissues of the epidermis or dermis, fat, or muscle.
A needle remover is a device used to physically remove a needle from a syringe. In developing countries, there is still a need for improvements in needle safety in hospital settings as most of the needle removal processes are done manually and under severe risk of hazard from needles puncturing skin risking infection. These countries cannot afford needles with individual safety devices attached, so needle-removers must be used to remove the needle from the syringe. This lowers possible pathogen spread by preventing the reuse of the syringes, reducing incidents of accidental needle-sticks, and facilitating syringe disposal.
Sharps waste is a form of biomedical waste composed of used "sharps", which includes any device or object used to puncture or lacerate the skin. Sharps waste is classified as biohazardous waste and must be carefully handled. Common medical materials treated as sharps waste are hypodermic needles, disposable scalpels and blades, contaminated glass and certain plastics, and guidewires used in surgery.
Drug injection is a method of introducing a drug into the bloodstream via a hollow hypodermic needle, which is pierced through the skin into the body. Intravenous therapy, a form of drug injection, is universally practiced in modernized medical care. As of 2004, there were 13.2 million people worldwide who self-administered injection drugs outside of medical supervision, of which 22% are from developed countries.
Charles Gabriel Pravaz a French orthopedic surgeon, pioneered the hypodermic syringe.
Cannula transfer or cannulation is a set of air-free techniques used with a Schlenk line, in transferring liquid or solution samples between reaction vessels via cannulae, avoiding atmospheric contamination. While the syringes are not the same as cannulae, the techniques remain relevant.
The carpuject is a syringe device for the administration of injectable fluid medication. It was patented by the Sterling Drug Company, which became the Sterling Winthrop, after World War II. It is designed with a luer-lock device to accept a sterile hypodermic needle or to be linked directly to intravenous tubing line. The product can deliver an intravenous or intramuscular injection by means of a holder which attaches to the barrel and plunger to the barrel plug. Medication is prefilled into the syringe barrel. When the plug at the end of the barrel is advanced to the head of the barrel it discharges and releases the contents through the needle or into the lumen of the tubing.
Intradermal injection is a shallow or superficial injection of a substance into the dermis, which is located between the epidermis and the hypodermis. For certain substances, administration via an ID route can result in a faster systemic uptake compared with subcutaneous injections, leading to a stronger immune response to vaccinations, immunology and novel cancer treatments, and faster drug uptake. Additionally, since administration is closer to the surface of the skin, the body's reaction to substances is more easily visible. However, due to complexity of the procedure compared to subcutaneous injection and intramuscular injection, administration via ID is relatively rare, and is only used for tuberculosis and allergy tests, monkeypox vaccination, and certain therapies.
A safety syringe is a syringe with a built-in safety mechanism to reduce the risk of needlestick injuries to healthcare workers and others. The needle on a safety syringe can be detachable or permanently attached. On some models, a sheath is placed over the needle, whereas in others the needle retracts into the barrel. Safety needles serve the same functions as safety syringes, but the protective mechanism is a part of the needle rather than the syringe. Legislation requiring safety syringes or equivalents has been introduced in many nations since needlestick injuries and re-use prevention became the focus of governments and safety bodies.
A low dead space syringe (LDSS) or low dead-volume syringe is a type of syringe with a design that seeks to limit dead space that exists between the syringe hub and needle.
Charles Hunter was an English physician best known for coining the word "hypodermic" and for realising that injections of morphine could relieve pain anywhere in the body, regardless of where the injection was delivered.
An injector pen is a device used for injecting medication under the skin. First introduced in the 1980s, injector pens are designed to make injectable medication easier and more convenient to use, thus increasing patient adherence. The primary difference between injector pens and traditional vial and syringe administration is the easier use of an injector pen by people with low dexterity, poor vision, or who need portability to administer medicine on time. Injector pens also decrease the fear or adversity towards self-injection of medications, which increases the likelihood that a person takes the medication.