
Overview
This module describes how to inject local anaesthesia using either a dental syringe or a
disposable needle and syringe
Useful to rule out intravascular injection via aspiration, or when a dental syringe is not available or accessible.
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Indications
Contraindications
Patient information and consent
Always verify your patient’s identity and obtain informed consent before proceeding.
How do I explain this procedure?
“I am going to give you an injection into the wound area that will make it numb.”
What can my patient expect?
“This injection will sting, but after a few minutes you will not feel any pain from the wound. You may still feel me moving and touching there while I work in the area, but it will not hurt. The numbness will go away in a few hours.”
What is my patient’s role?
“Let me know if you have any allergies. Fearing blood or needles is normal, but tell me if you have fainted from it. Stay very still while I give this injection.”
Preparation
Prepare a trolley with equipment.
Documentation
Equipment

If no dental syringe/needle/lignocaine cartridges:

Site & Positioning
Ask the patient to sit or lie with the area exposed and within easy reach.
The principle is to pierce the skin as few times as possible, but to infiltrate the entire area with local anaesthetic.
Procedure
Follow medical asepsis with sterile gloves.
For disposable needle and syringe method, omit steps 3 to 12, as well as step 18. Follow the same method of injecting, but aspirate prior to injecting the anaesthetic.
Troubleshooting
My patient is still feeling pain.
Make sure you wait a full 10 minutes before testing the patient’s sensation. If there is still pain, make sure you injected enough lignocaine into the entire area. Check the lignocaine expiry date. Local infection can also reduce the effectiveness of local anaesthetics. Rarely, some patients may be resistant to local anaesthetics.
The plunger of the dental syringe won’t depress
Recap the needle using a no touch technique first. Hinge open the syringe and check that the plunger is connected properly. In some very old syringes, rust may have collected. Sometimes removing and reinserting the cartridge helps. If this fails, use another dental syringe or a disposable needle and syringe