PHARMAC-05 Local Anesthesia.ppt

7/30/2019 PHARMAC-05 Local Anesthesia.ppt

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LOCAL ANESTHESIA

PHARMAC-05


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LOCAL ANESTHESIA

PHARMA-05


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Definition

PAIN:Defined as an unpleasant emotional experience

usually initiated by a noxious stimulus andtransmitted over a specific neural pathway to the

CNS where it is interpreted as such.

LOCAL ANESTHESIA:Defined as loss of sensation in a circumscribed

area of the body caused by a depression ofexcitation in the nerve endings or an inhibition ofconduction process in peripheral nerves.


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Ideal requirements of a local anesthetic drug

1. Reversible

2. Stable in solution

3. Non irritating to tissues

4. Should not cause any permanent alteration innerve

5. Low systemic toxicity

6. Rapid onset and enough duration of action

7. Potent enough to give complete anesthesiawithout using harmful concentrations

8. Relatively free from producing allergic reactions


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Indications of regional analgesia

1. Conscious state of patient in minor oral surgicalprocedures desired

2. Diagnostic and Therapeutic purposes3. For bloodless field during surgical procedures as an

adjunct when used with vasoconstrictor

ContraindicationsABSOLUTE: Allergy

RELATIVE: 1.Local infections2.Uncooperative patient3.Fear or apprehension4.Major oral surgical procedures5.Systemic conditions like renal or liver

disease affecting the metabolism and excretion of drug


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The Concept Of LA

They prevent both generation and conduction of

a nerve impulse.

LA sets up a chemical roadblock between the sourceof impulse and the brain.

Thus, the aborted impulse, prevented from reachingthe brain is not interpreted as pain.


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Classification Of LA Drugs

1.BASED ON COMPOSITION

A. Natural: cocaine

B. Synthetic nitrogenous compounds:

PABA - Procain, Benzocainacetanilide- Lignocaine

Quinoline- centbucridine

C. Non nitrogenous compounds:

Benzyl alcoholD. Miscellaneous:

Clove oil, phenol.


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A.ESTER GROUP

Cocaine

Benzocaine

Tetracaine

Butaine

Procaine Propoxycain

2-Chlorprocaine

B.NON-ESTER GROUP

Lidocaine

Mepivacaine

Pyrocaine

Bupivacaine

Prilocaine

2.ACCORDING TO CHEMICAL STRUCTURE


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3.ACCORDING TO DURATION OF ACTION

1.Ultrashort acting(


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3.Medium acting

a) 4% prilocaine with 1:200000 epinephrine.

b) 2% lidocaine with vasoconstrictor

4. Long acting (180 minutes or long)

a) 0.5% bupivacaine with 1:200000

epinephrineb) 0.5 %etidocaine with 1:200000 epinephrine.


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Techniques

3 major types of local anesthetic injections:

LOCAL INFILTRATION:

LA deposited near small

terminal nerve endingsFIELD BLOCK:

LA deposited near larger

terminal nerve branches.

NERVE BLOCK:LA deposited close to main

nerve trunk.


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Maxillary Injection Techniques

1.Anesthesia for Teeth and Buccal soft and hardtissues: a) Supra periosteal

b) Posterior Superior alveolarc) middle superior alveolar

d) Anterior superior alveolar2.Palatal: a) Greater palatine

b) Nasopalatinec) Local infiltration

d) AMSAe) Palatal approach-ASA

3.Maxillary Nerve block


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REGIONAL ANESTHESIA TO PULPS OF SOME OR ALLTEETH:

1. Inferior alveolar nerve block

2. Gow-gates mandibular nerve block

3. Incisive nerve block

4. Vazirani-akinosi (closed mouth)

REGIONAL ANESTHESIA FOR SOFT TISSUES ONLY:1. Buccal nerve block

2. mental nerve block


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DEFINITION:

Any deviation from the normally expected

pattern during or after securing of local

anesthesia.

CLASSIFIED AS: primary/secondary

mild/ severe

transient/permanent.


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COMPLICATIONS: Toxicity

Allergy

Syncope

Trismus

Broken needles

Hematoma

Sloughing


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CAUSES: 1.Overdosage

2. unusually rapid absorption intravascular

injection

3. slow elimination or distribution.SYMPTOMS:

1.talkitiveness 6.sweating

2.apprehension 7.disorientation

3.exitability 8.elevated B.P.4.sluttered speech 9.respiratory rate high

5.euphoria


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PREVENTION:

1. Preanesthetic evaluation must.

2. Select drug with care.

3. Use least possible volume.4. Deposit solution slowly.

5. Aspiration is must.

6. Use vasoconstrictor if not contraindicated.

7. Do not give LA beyond recommended doses.BASIC EMERGENCY MANAGEMENT:

P A B C D


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SYMPTOMS:

Rashes

Urticaria

Angioneurotic edema

Mucous membrane

congestion

rhinitis

asthmatic symptoms

TREATMENT:Antihistaminic agents

Benadryl:20-50 mg

Epinephrine-0.5ml of

1:1000 IM

Aminophylline-0.5gm IV

Oxygen


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TREATMENT:

Should be done before patient loses consciousness.

Detect change in appearance-pallor.

Discontinue any procedure.

Semi-reclined position.


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Conscious patient: instruct to take few deep breaths.

Unconscious patient: check vitals

if beyond normal limits give

artificial ventilation.


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Prolonged tetanic spasm of jaw muscles

Restricted mouth opening.

Causes: Trauma

Infection or irritating solutions.

Management:1.heat therapy

2.warm saline rinses

3.muscle relaxants

4.physiotherapy5.antibiotics if symptoms persist.

6.surgery if chronic dysfunction exists.


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Most annoying and depressing complication.

Causes: 1. bending before insertion.

2. sudden patient movement.

3. use of fine needles.

Management:

If visible: instruct patient not to move.

remove with hemostat or Magill forcep.

If lost: do not proceed with incision or probing

refer patient for consultation. If in deeper tissues: let it remain without attempt at

removal.

li i l


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Clinical Aspects

Max dose of lidocaine without adrenaline is = 300mg Max dose of LA with adrenaline = 500mg

Max safe dose of adrenaline =0.2mg/visit

2% Lignocaine= 2g in 100 ml2000mg in 100 ml

20 mg in 1ml

1 mg= 1/20

500mg=1/20500= 25ml can be given safely for a normal pt

Adrenaline present in our vials is in conc. of 1:80,000

1ml=1/80,000=0.0125mg

0.0125mg-1ml

As MRD-0.2mg , so for normal pt- 0.2 mg=1/0.01250.2=16ml of LA can be

administered safely


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THANK YOU

Date post:	04-Apr-2018
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PHARMAC-05 Local Anesthesia.ppt

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