brief review of local anesthesia use

1. LOCAL ANESTHESIA ADMINISTRATION
PROTOCOL
By workneh t(MD,general surgery resident)
JIMMA NOVEMBER 2017
INTRODUCTION
This clinical protocoloutlines the circumstances in which local

2. anaesthetics are used, contraindications and cautions when using.
It should be stressed that the use of local anaesthetics is very safe
and is the mainstay of pain and anxiety control in minor operative
procedures.
All injectable local anaesthetics are prescription only medicines and
as such they must be prescribed by an authorised prescriberor
administered via an appropriately ratified patient group direction.
Anesthetic drugs used for local infiltration

3. Lidocaine 1% or 2%,bupivacaine,mepivacaine and others.
Mode of action
Local anaesthetics work by causing a reversible blockage of impulse
propagation along nerve fibres by preventing the inward movement of sodium
ions through the nerve membranes. But If delivered in excessive doses or
inadvertently given intravascularly, local anaesthetic medicines may rapidly
reach the systemic circulation and affect the excitable membranes of the brain
and myocardium.
Onset and duration of action
Table 1.shows onset and duration of action for some local anesthetic drugs
Anesthetic Onset (min) Duration (min)
With epinephrine Without epinephrine
Bupivacaine 2-10 120-240 240-480
Lidocaine 1 30-120 60-400
Mepivacaine 3-20 30-120 60-400
Etidocaine 3-5 200 240-360
Procaine 5 15-90 30-180
Use of vasoconstrictors
Local anaesthetics cause dilation of blood vessels. The addition of a
vasoconstrictor such as adrenaline [epinephrine] to the local anaesthetic
preparation diminishes local blood flow, slowing the rate of absorption and
prolonging the anaesthetic effect, hence reducing the total dose required to
achieve adequate analgesia.
Adrenaline [epinephrine] must not be administered with a local
anaesthetic in digits or appendages, because of the risk of ischaemic
necrosis.
Recommended dose
The maximum safe dose of local infiltrated anesthesia is unknown
For adults, no more than 4.5 mg/kg of lidocaine and 7.0 mg/kg of lidocaine with

4. epinephrine should be administered in a single treatment
For children, no more than 1.5-2.0 mg/kg of lidocaine and 3.0-4.5 mg/kg
of lidocaine with epinephrine should be administered in a single
treatment.Table 2 below shows safe dose for local anesthetic drugs.
Table 2 shows maximum recommended dose for local anesthetic drugs
Anesthetic Maximal recommended dose for adults
Without epinephrine With epinephrine
Bupivacaine 2.5 mg/kg or 175 mg 3.0 mg/kg or 225 mg
Lidocaine 4.5 mg/kg or 300 mg 7.0 mg/kg or 500 mg
Mepivacaine 6.0 mg/kg or 400 mg 7.0 mg/kg or 550 mg
Etidocaine 4.5 mg/kg or 300 mg 6.5 mg/kg or 400 mg
Procaine 10.0 mg/kg 14.0 mg/kg
Contra-indications to local anaesthetics
Patients with hypersensitivity
Patients with porphyria should not be given articaine or mepivicaine and
Local anaesthetics can cause ototoxicity and should not be applied to the
middle ear
Cautions for administration of local anaesthetics
The use of local anaesthetics should be carefully considered in any patient
who is currently systemically unwell or who has an unstable medical condition.
Local anaesthetics should be administered with caution in children, elderly
or debilitated patients (consider dose reduction), or in patients with impaired
cardiac conduction, cardiovascular disease, hypovolaemia, shock,
impaired respiratory function, epilepsy, or myasthenia gravis.
Side effects of local anesthesia
They may cause hypersensitivity reactions or idiosyncrasy, persistent
paresthesias, lightheadedness, nervousness, apprehension, euphoria, confusion,

5. dizziness, headaches, malaise, agitation, drowsiness, tinnitus, blurred or double
vision, nausea, vomiting, sensations of heat, cold or numbness, twitching, tremors,
convulsions and faintness.
Administration
 Prior to any clinical session, adrenaline 1mg in 1ml must be available to be
administered in the rare event of an anaphylactic reaction.
 Take a detailed medial history to establish if there are any known
contraindications
 The lowest dosage that results in effective anaesthesia should be used
 Anesthetic should be administered slowly using an aspirating technique
in order to detect inadvertent intravascular administration
 If blood is aspirated, the needle must be repositioned until there is no
return of blood in the syringe
 If adequate anaesthesia not achieved with the maximum recommended
dose abandon the procedure.
 Maximum arterial plasma concentration of anaesthetic develops within
about 10 to 25 minutes, so careful surveillance for toxic effects is
necessary during the first 30 minutes after injection.
RECORDS
A full record of all local anaesthetics prescribed and/or administered must be
made in the patient’s record including the name of the local anaesthetic, the
amount administered, batch number and expiry date.