- Do not use lignocaine with adrenaline to infiltrate areas with an end-arterial supply, such as fingers, toes, pinna, penis and nose.
- Local anaesthetic allergy (uncommon).
Use of adrenaline:
- Use local anaesthetic with adrenaline for vascular sites or for sites where the skin needs to be incised, because adrenaline causes vasoconstriction.
- Adrenaline will reduce systemic absorption, maintain a higher anaesthetic concentration near nerve fibres and prolong local anaesthetic conduction blockade.
- Maximal effect with the less lipophylic anaesthetic agents (e.g. lignocaine). Note: The more lipophilic local anesthetics will tend on their own to associate strongly with tissues
Calculating the maximum dose of local anaesthetic agent
- Maximum dose of lignocaine without adrenaline is 3 mg/kg.
- Maximum dose of lignocaine with adrenaline is 7 mg/kg.
- Lignocaine concentration in solution:
- 0.25% = 0.25 g/100mL or 2.5mg/mL
- 0.5% = 0.5 g/100mL or 5mg/mL
- 1% = 1 g/100mL or 10mg/mL
- 2% = 2 g/100mL or 20mg/mL
- Thus, in a 70-kg patient do not use more than:
- 20 mL 1% plain lignocaine or 10 mL 2% plain lignocaine
- 48 mL 1% lignocaine with adrenaline or 24 mL 2% lignocaine with adrenaline
- The sting of lignocaine infiltration may be reduced by warming the solution to T37 deg C prior to administration and by the addition of HCO3.
- Placing the needle “up to the hub” and injecting while withdrawing along the just-created sub-dermal tunnel minimizes tissue distention and pain.
- After an initial injection, instead of totally withdrawing the needle from the tissue, redirect it along another path to lessen the number of punctures.
- If multiple injections are required, enter the skin through an area that has already been infiltrated.
- Slowly injecting the smallest volume necessary reduces pain
- Make all wound injections through the wound edge and not through the skin
|Onset (min)||Duration (min)||Max dose (mg/kg)||Max mg (70kg person)|
|Ligocaine (1% or 2%)
|Ligocaine with adrenaline
(1% or 2%)
|Bupivicaine with adrenaline||5||180-420||3mg/kg||225mg|
|Prilocaine (0.5% or 1%)