Giving local anaesthetic before closing a wound
Local anaesthetic (LA) used to numb area before doing painful procedure (eg suturing)
Attention
- Do not use local anaesthetic + adrenaline (epinephrine) for fingers, toes, penis
- 2–5mL of lidocaine (lignocaine) 1% usually needed for most procedures
- Maximum safe dose is 3mg/kg up to 200mg OR medical consult for higher dose
- Lidocaine (lignocaine) 1% is 10mg/mL
- If wound bleeding use lidocaine (lignocaine) 1% + adrenaline (epinephrine) 1:100,000
- Topical anaesthetic (skin) patches
- Do not leave on for more than one hour — anaesthetic may be absorbed and cause symptoms such as dizziness, headache, fast pulse, cyanosis (blue skin), especially in children
- Before injecting, always pull back on (withdraw) syringe plunger to make sure you are not in vein/artery
- To lessen pain
- Warm local anaesthetic to room temperature and inject s-l-o-w-l-y
- Consider using anaesthetic spray on skin before first injection
- Commence through the wound edge
- LA can be injected as needle pulled back out through tissue. Will anaesthetise all tissue in its path
- If needle pulled out steadily and continuously — LA should not be injected into vein or artery — practice on a piece of meat
- ‘Fanning’ — technique used to inject wide area of tissue from single injection point
- Needle put in at one spot then moved around in clockwise or anti-clockwise direction to anaesthetise a bigger area (eg sural (foot) nerve block, episiotomy)
- Wait 10 minutes for LA to work before starting procedure
- Check area for feeling using sharp needle. Also gives person confidence
- Ask person to feel around their own wound to give them confidence that local anaesthetic is working
Direct infiltration
Attention
- Try flushing wound with small amount of LA before first injection. Wait 2–3 minutes for this to work
- Do not go too deep with injection. Anaesthesia may be delayed or not work at all
- Aim to put needle below dermal layer of skin and above fat layer
- If needle in dermal layer — will be hard to press down syringe plunger. Take it out, try again a little deeper
- Scalp wounds may need bigger needle to infiltrate — tissue is tough
What you need
- Bluey
- Sterile dressing pack
- Normal saline for cleaning
- 2–5mL of lidocaine (lignocaine) 1%
- 5mL syringe, 21G needle for drawing up, 23G or 25G needle for injection
- Sterile gloves
What you do
- See Examining and cleaning a wound before closing
- Put bluey under site
- Lay out dressing pack, equipment
- Wash hands, put on sterile gloves
- Clean site, drape with sterile towels
- Draw up LA
- Starting at one end of wound, slide needle through wound edge under dermal layer and above fat — Figure 7.26, needle a
- Pull back on plunger to check for vein/artery, then inject anaesthetic as you pull needle out. Will anaesthetise shaded area around A — Figure 7.26
- Wait a few moments until anaesthetic is working, so person doesn't feel it, then push needle into anaesthetised area at tip of previous injection — Figure 7.26, needle b. Repeat injection as above
- Keep doing this until wound is anaesthetised along its whole length, then repeat process on other side — Figure 7.26, needle c and needle d
- If wound short — may only need 1 injection on each side
- Make sure ends of wounds also injected with LA
- Wait for anaesthetic to work. Use needle to test for feeling before you start suturing
Figure 7.26
Parallel margin infiltration
Attention
- More painful than direct infiltration. Only use if wound very dirty and needle may take dirt further into tissue
What you need
- Bluey
- Sterile dressing pack
- Normal saline for cleaning
- 2–5mL of lidocaine (lignocaine) 1%
- 5mL syringe, 21G needle for drawing up, 25G needle for injection
- Sterile gloves
What you do
- See Examining and cleaning a wound before closing
- Put bluey under site
- Wash hands, put on sterile gloves
- Lay out dressing pack, equipment
- Clean site, drape with sterile towels
- Draw up LA
- Starting at one end of wound about 4mm from edge, push needle in, keeping parallel to wound edge — Figure 7.27, needle a
- Pull back on plunger to check you are not in vein/artery, then inject anaesthetic as you pull needle out
- Wait a few moments, push needle into anaesthetised area at tip of previous injection, inject as before — Figure 7.27, needle b
- Keep doing this until wound anaesthetised along its whole length, then repeat process on other side — Figure 7.27, needle c and needle d
- If wound short — may only need 1 injection on each side
- Make sure ends of wounds also injected with LA
- Wait for anaesthetic to work. Use needle to test for feeling before you start suturing
Figure 7.27