Medical injection techniques: the basics of administering active substances using a syringe
An injection delivers medication into the body using a needle and syringe; the effect usually sets in more quickly than when taken orally.
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Important note
This article is for information purposes only and is not a substitute for a medical diagnosis or advice. If you are unsure, or if you require a personalised treatment plan, it is essential that you consult a qualified specialist.
Definition of the injection technique: What is an injection?
An injection is the administration of a liquid or injectable solution into the body using a hollow needle (cannula) and a syringe. It is used to administer medicines, vaccines or even contrast agents. A key feature of an injection is that the onset of action is often faster compared to oral administration, where active substances must first pass through the digestive tract and are partially broken down before they enter the circulatory system. The type of injection and the choice of technique depend on the active substance, the desired site of action and the desired rate of onset. For the injection of medicines, such as those used to treat diabetes (insulin), this is often the method of choice.
An overview of the main types of injection
There are various types of injection, which differ primarily in terms of the depth and site of administration within the tissue. Each technique requires specific knowledge.
Subcutaneous injection (s.c.)
In a subcutaneous injection, the active substance is injected into the subcutaneous fatty tissue (subcutis), often in the abdomen or thigh. This method is frequently used for medicines such as insulin or heparin for thrombosis prophylaxis, which are intended to be absorbed slowly and evenly by the body. A subcutaneous injection usually requires a short needle. Sometimes the skin needs to be stretched for the injection, or a skin fold of approximately 2 cm needs to be formed.
Intramuscular injection (i.m.)
An intramuscular injection is administered directly into a muscle. The gluteus medius muscle (a gluteal muscle) or the outer side of the thigh are typical injection sites. Muscle tissue is well supplied with blood, which enables rapid absorption of the active substance. Many vaccinations and painkillers are administered in this way. An intramuscular injection is a deep injection.
Intravenous injection (i.v.)
With an intravenous injection, the active substance is injected directly into a vein (e.g. the vena mediana cubiti in the crook of the elbow), enters the bloodstream immediately and produces the fastest effect. This technique is complex and must only be carried out by experienced staff, as errors can have serious consequences (including cardiac arrest if certain substances are administered incorrectly). It enables rapid administration.
Intracutaneous injection (i.c.) / Intradermal injection
In this procedure, a very small amount of the active ingredient is injected into the top layer of the skin (the dermis). It is used for allergy tests or local anaesthesia.
Other types of injection
There are also medicines and specific injections for less common applications, such as intra-arterial administration. Sterile single-use syringes or pre-filled syringes are now used for many applications.
Preparing for and administering a safe injection
Careful preparation and administration of the injection are crucial. This involves:
- Hygienic hand disinfection
- Preparation of equipment: Sterile syringe (often a disposable syringe), suitable needle, medication or injection solution, disinfectant. The injection solution is drawn up into the syringe in a sterile state from an ampoule or vial.
- Selection and disinfection of the puncture site
- Correct technique in accordance with the method of injection and the substance to be administered
- Safe disposal of the cannula
Risks and complications associated with injections
Every injection, even one that appears straightforward, is a medical procedure and carries a certain risk. Errors can lead to pain, infections, tissue damage or nerve damage. A complication may also impair the effectiveness of the medication. As an injection constitutes a bodily intervention, the patient’s consent is absolutely essential. If consent is not given and the injection is administered or withheld (in the case of necessary treatment) nonetheless, this may result in legal consequences (Section 230 of the German Criminal Code). The need for a rapid or local effect is an argument in favour of the injection.
Qualification for carrying out injections
As a general rule, medical injections may only be administered by doctors or qualified medical staff. The attending doctor bears responsibility. Doctors may delegate the administration of certain injections to suitably qualified healthcare professionals. These healthcare professionals administer the injection in accordance with the doctor’s instructions and on the basis of their proven qualifications. It is common practice to have suitably trained staff administer certain injections.
Safety and precautions when giving injections
Patient safety is the top priority. It is important to provide comprehensive information about the specific injection and any potential risks. In the case of cosmetic procedures, which often involve specific injections, it may be advisable to take out Consequential Costs Insurance This may be a sensible consideration to protect oneself against the financial burden of unforeseen follow-up treatment.
| aspect | Description |
|---|---|
| Objective | Parenteral administration of active substances |
| Material | Sterile syringe, sterile needle, disinfectant, active ingredient |
| Importance | Correct technique for effectiveness and safety, and to avoid complications |
| Implementation | To be used only by qualified personnel in accordance with a doctor’s instructions |
In summary, it can be said that medical injection techniques are an indispensable tool. Their safe use is based on knowledge, precision and hygiene.