Injections

Introduction

Definitions

Injections are sterile solutions, emulsions or suspensions. They are prepared by dissolving, emulsifying or suspending the active ingredient and any added substances in either water for injections or a suitable non-aqueous liquid or in a mixture of these vehicles.

Types of injections and infusions

• Intradermal injection

• Subcutaneous injection and infusion

• Intramuscular injection

• Intra-arterial injection

• Intraosseous injection

• Intra-articular injection

• Intrathecal injection and infusion

• Intravenous:

  • bolus injection

  • intermittent and continuous infusion

Evidence-based approaches

Medicines should only be administered by injection when no other route is suitable or available. As injections avoid the GI tract, this is described as parenteral administration. 

Injections would be administered when: 

• Medications might be destroyed by the stomach; 

• rapid first-pass metabolism may be extensive; 

• the drug is not absorbed when given orally; 

• precise control over dosage is required; 

• unable to be given by mouth; 

• need to achieve high drug plasma levels 

There are disadvantages as injections are invasive, cause pain and discomfort, and can put the patient at risk of infection and, in the case of intravenous injections, infiltration and extravasation.

(Royal Marsden 2015)

Pre-procedural considerations

Please watch screen cast below, have also left the power point in in case you want to come back to it for reference or the transcript

How to choose the correct needle

This short video explains the parts of a syringe and the graduation numbers on different types and sizes of syringes.

This is a really useful video that also includes some questions (and provides answers) to test your own knowledge.

Injection techniques

This short video provides a clear picture about the different layers of the skin and different types of injection.

Risk

• Nurses also need to be aware of the risk of a sharps injury when administering an IM injection. 

• An estimated 40,000 needlestick injuries occur in the NHS each year. 

• Various measures to reduce the risk of sharps injuries can be implemented, such as considering alternative administration routes, having an accessible sharps container during administration, and avoiding re-sheathing needles

Reducing pain of injections

Patients are often afraid of receiving injections because they perceive the injection will be painful (Downie et al. 2003). Torrance (1989) listed a number of factors that cause pain.

• The needle.

• The chemical composition of the drug/solution.

  • • The technique.

• The speed of the injection.

• The volume of drug.

Applying manual pressure to an injection site before performing an injection can be an effective means of reducing pain intensity (Chung et al. 2002). A small study carried out by Chan (2001) showed that administering subcutaneous heparin slowly (over 30 seconds rather than 10) can reduce site pain intensity as well as bruising. Pain may also be reduced when using retractable needles (Lamblet et al. 2011).

Reducing the pain of injections

• Correct length and gauge of needle (use smallest possible).

• Correct site.

• Correct angle (90° for IM).

• Correct volume (no more than 3 mL at a site for IM).

• Rotate sites to prevent formation of indurations or abscesses.

• Consider using ice, freezing spray or topical local anaesthetic to numb the skin.

• Listen to views of the experienced patient.

• Explain the benefits of the injection.

• Positioning of the patient so that the muscles are relaxed.

• Use distraction.

• If appropriate, ask the patient to turn their foot inwards (IM).

• Insert and remove the needle smoothly and quickly.

• Hold the syringe steady once the needle is in the tissue to prevent tissue damage.

• Inject medication slowly but smoothly.

Source: Adapted from Dickerson (1992), Downie et al. (2003), Potter (2011) cited in Royal Marsden (2015)