Syringe (medicine)

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Disposable plastic syringe and disposable cannula with the protective cap removed
Reusable glass syringe without cannula, record attachment
Disposable syringe (insulin syringe) with attached cannula
Pre-filled syringes; before use with protective cap (above), empty syringe with activated needle safety mechanism (below)
Wound irrigation and bladder syringe
Filled syringe with infusion line in a syringe pump

A syringe is a medical instrument that is used to administer medication, nutrient and infusion solutions (as an injection or infusion ), to remove body fluids ( puncture ) or tissue ( biopsy ), and to rinse (e.g. wounds).

The first injection syringe with which liquid medication - so-called injectables - could be administered was developed by the French Charles-Gabriel Pravaz in 1841 and became more widespread from around 1853.


A syringe consists of a cylindrical cavity, a movable piston and a conical or cylindrical nozzle ( Luer Slip ). There are also versions with a screw thread on the nozzle (Luer lock). A hollow needle ( cannula ) or a tube can be connected to this. Commercially available sizes range from 0.5 to 100 ml in volume.

Disposable syringes are usually individually and sterile packed. They are made of plastic such as polypropylene or cycloolefin copolymers . There are two-part syringes that only consist of the cylinder and a piston, and three-part syringes that have a rubber stopper at the lower end of the piston. With smaller syringes (e.g. insulin syringes) the cannula is glued in place. The drug solution to be administered is already included in the pre-filled syringes ; some makes are equipped with a mechanism that securely locks the integrated cannula after the injection.

The outer plunger end of syringes for dosing pumps is shaped so that the holder can click into place. The device recognizes a compatible syringe and adjusts its control accordingly. Syringes from another manufacturer are often useless for the purpose.

Despite the designation “disposable syringe”, some makes could - contrary to the hygiene guidelines - be reused. In order to actually rule out multiple use, the so-called AD (“Auto-disable”) syringe was developed. There are various solutions and patents that prevent re-opening (predetermined breaking point on the piston, valves, etc.). UNICEF vaccination campaigns are only carried out with AD syringes.

Reusable syringes such as the cartridge or cylinder ampoule syringe are made of glass, metal and rubber. They are rarely used in human medicine because they have to be reprocessed at great expense in order to comply with hygienic regulations. Revolver syringes are used in veterinary medicine.


Before injections, irrigation or liquid administration, the syringe is filled by pulling the plunger (aspiration). A withdrawal cannula is usually used for this purpose; This is usually not necessary with enteral nutrition or medication administration through a feeding tube. Pressing the plunger forces the contents of the syringe through the nozzle. The resulting pressure depends on the plunger area of ​​the syringe: A smaller area causes a higher pressure than a larger one with the same effort. It is therefore recommended, for example, for port injection, to use syringes with a volume of at least 10 ml, as otherwise the catheter may disconnect or tear.

When removing body secretions or tissue, an empty syringe or a syringe partially filled with an additive (for example a blood collection tube ) with a corresponding cannula is placed on or in the removal site or access. The syringe is filled by aspiration. If necessary, the contents are transferred to a sample container by the reverse process.

Puncture and injection

An injection is usually also a puncture . For this purpose, a cannula or trocar corresponding to the type of puncture or injection must be placed on the syringe cone. If medication is administered with a syringe, it is referred to as an injection. With so-called pre-filled syringes, there is no need to attach a cannula; The same applies to patients who have access that is suitable for injection, for example an indwelling venous cannula or a pierced port .

Special injection systems have been developed for administering insulin, including the so-called pen . The needle-free injection is not carried out with a syringe, but with a vaccination gun that is no longer recommended for human medicine .


Using a syringe pump , drug solutions can be administered in a controlled manner at a pre-programmed speed. For this purpose, a sterile syringe compatible with the device is filled with the infusion solution under aseptic conditions, connected to a sterile infusion line and clamped into the device.

Fluid and food administration

Using a bladder syringe, small portions (up to 50 ml) of liquid, liquid food or liquid or dissolved medication can be administered through a feeding tube. These bolus doses are given when only small amounts of food and fluid are to be supplied at longer intervals, which does not require a gravity system or a feeding pump. With a syringe only filled with water, the probe is rinsed after each feeding to prevent sticking. No needles are required for drawing up or emptying the syringe, but rather special connectors or attachments (adapters). This prevents tube feeding from being inadvertently administered through a venous access.

Other uses

To fix (block) balloon probes , catheters and tracheostomy tubes inside the body, syringes without a needle are required. Depending on the manufacturer's instructions, the balloon (or cuff ) is blocked with a certain amount of air, sterile aqua distillata or sterile saline solution ; to unblock it is aspirated.

Special enema syringes or bladder syringes are used for enemas . Cannulas cannot be placed on these syringes. The bladder syringe is also used to irrigate wounds: in conjunction with a short, flexible and sterile disposable catheter , it can be used to reach hard-to-reach wound cavities. Often, however, smaller syringes are sufficient, on which a button cannula is placed if necessary. On the other hand, the urinary bladder is manually rinsed with special bellows bottles via a catheter, which build up less pressure than a bladder syringe.

Syringe cylinders are used as an attachment for certain analysis methods in the context of biomonitoring ( solid phase extraction ).

Disposal of injection syringes in Germany

About half of all reported insurance claims in the health service can be traced back to needlestick injuries , including cuts and scratches to the skin from stabbing or cutting instruments. The trade association for health service and welfare (BGW) cites as one cause that pointed and sharp instruments such as cannulas , lancets , needles and scalpels are not disposed of correctly immediately after use. In addition, an uncleaned or overfilled waste container is named as a source of danger. The classification and disposal of used pointed and sharp objects is guided by the Federal / State Working Group on Waste (LAGA) in its notification 18. They are to be collected, made available and disposed of in accordance with waste code 180101. For contaminated objects that are afflicted with notifiable pathogens, additional requirements also apply.

For safety reasons, all injection syringes used at home must be collected in puncture-proof and break-proof waste containers that are also used by doctors' offices. This also applies to disposable syringes with a protective mechanism, in which a protective cover slides over the needle after the injection. Such a needle disposal box can be obtained from clinics and pharmacies or ordered on the Internet. Used injection syringes should be collected immediately after use in waste containers that safely enclose the waste. These containers must be set up as close as possible to the place of use. Overfilling or transferring must be avoided for safety reasons.

The closed collection containers can generally be disposed of in the residual waste.



For the proper handling of injections, further training courses are offered to acquire a so-called 'injection certificate'. The contents basically belong to the training of nursing staff and medical assistants (MFA) , the practical implementation is regulated differently from country to country.

Syringe machines

In order to avoid additional health risks for drug addicts through needlesharing and self-made injection devices, syringe machines were set up.


  • S.Schewior-Popp, F. Sitzmann, L. Ullrich (eds.): Thiemes Pflege. Georg Thieme Verlag, Stuttgart 2009. ISBN 978-3-13-500011-4 .
  • C. Schäfer (Hrsg.): Probe application of drugs for the smock pocket. Scientific publishing company, Stuttgart 2010.

Web links

Commons : Syringe  - album with pictures, videos and audio files
Wiktionary: Syringe  - explanations of meanings, word origins, synonyms, translations

See also

Individual evidence

  1. ^ Definition of Infusion ,; accessed on March 18, 2020
  2. ^ Rudolf Frey , Otto Mayrhofer , with the support of Thomas E. Keys and John S. Lundy: Important data from the history of anesthesia. In: R. Frey, Werner Hügin , O. Mayrhofer (Ed.): Textbook of anesthesiology and resuscitation. Springer, Heidelberg / Basel / Vienna 1955; 2nd, revised and expanded edition. With the collaboration of H. Benzer. Springer-Verlag, Berlin / Heidelberg / New York 1971. ISBN 3-540-05196-1 , pp. 13–16, here: p. 14.
  3. Ulf K. Teichgräber, Robert Pfitzmann, Herbert AF Hofmann: Port systems as an integral part of chemotherapy . In: Dtsch Arztebl Int . No. 108 (9) , 2011, pp. 152 ( abstract ).
  4. Kerstin Protz: Modern wound care. 7th edition. Urban & Fischer, Munich 2014, pp. 17–18.
  5. Handling urinary catheters - bladder irrigation. In: I care care. Thieme, Stuttgart 2015; P. 448
  6. Risk of needlestick - BGW-online. Retrieved October 30, 2018 .
  7. Publications / communications - Federal / State Working Group on Waste (LAGA). Retrieved October 30, 2018 .
  8. Disposal of syringes . In: Waste Manager Medicine . ( [accessed October 30, 2018]).
  9. Pharmacies, pollutant collection points or household waste: Dispose of old medicines responsibly . In: Waste Manager Medicine . ( [accessed October 30, 2018]).
  10. Injection gauge / injection certificate. Retrieved January 2, 2019 .
  11. Syringe distribution in prison in 1996. Accessed on January 2, 2019 .
  12. Infection prophylaxis in prisons. Retrieved January 2, 2019 .
  13. Syringe machines. Fixed point, accessed on January 2, 2019 .