Local anaes Flashcards
Define local anaesthesia
Loss of sensation to specific anatomical area
What are the 2 main uses of LA in dentistry
- Enable surgical procedures to be undertaken
2. Provide analgesia
Name the different way we can produce local anaesthesia
- Cooling sensation of topical application of ethyl chloride
- Pressure
- Try LA agents injected into nerve fibres
- Irreversabel blockades
How can we administer local anaesthesia
- Topical
- Subcutaneous injection
- Nerve blockers
- Epidural
- Intrathecal
What is an Intrathecal injection
Injecting directly into the subarachnoid space
Name the first known substance used as LA
Cocaine
Give examples of different local anaesthetics
- Lidocaine
- procaine
- Pilocaine
- Mepivicaine
- Ropivacaine
- Bupivicaine
- Articaine
What do we often give alongisde the anaesthetic agents
A vasoconstrictor
What are the benefits of administrating a vasoconstrictor
- Longer duration of LA
- Can reduce risk of CNS effects
- Greater anaesthetic affect so lower dose can be given
Where should we not administer LA with a vasoconstrictor? why?
into extremities as there is a risk of significant local tissue hypoxia
Name the 2 most common vasoconstrictors use din dentistry
- Adrenaline
2. Felypressin
What us another name for adrenaline
Epinephrine
What is another name for felypressin
Vasopressin
How do adrenaline work
It stimulates alpha adrenoreceptors to constrict blood vessels
Name the most common dental LA solution
2% lidocaine with 1:80,000 adrenaline
What dow e mean by 2% lidocaine
20mg per ml
When might LA with adrenaline be contraindicated
In patients with severe hypotension or an unstable cardiac rhythm
If we can’t use adrenaline as a vasoconstrictor what can we use instead
Felypressin
List the ideal properties of an LA
- Be reversible
- Have a high therapeutic index
- Have a short time of onset
- Last for a suitable amount of time for treatment
- Not have local irritant effects
- No side effects
- No potential to induce allergy
- Be applicable to any site
- Be cheap to manufacture, stable and soluble
List some possible adverse effects of LA
- Hypersensitivity
- CNS effects
- Cardiac arrest
- Methaemoglobinaemia
What is an allergic reaction to LA usually due to
The preservatives rather than the local
List some early CNS effects LA can have
- light-headedness,
- dizziness,
- tinnitus,
- circumpolar numbness,
- abnormal taste,
- confusion,
- drowsiness
List some late CNS effects LA can have
- tonic-clonic seizures,
- loss of consciousness,
- respiratory depression
- arrest
What is Methaemoglobinaemia a very rare side effect to
Felypressin
What are the symptoms of Methaemoglobinaemia
- Cyanosis
- lethargy
- Respiratory distress
When can Methaemoglobinaemiabe more risky
In a patient With angian or anaemia
How do we treat Methaemoglobinaemia
Be treated as a medical emergency give oxygen and call an ambulance
What is the max dose of lidocaine we can give for infiltration
4mg/kg