Anaesthesia & Exodontia Third Year

1. LOCAL ANAESTHESIA
Local and Systemic
Complications of LA
Dr. Adel I. Abdelhady
BDS, MSC, (EG) PhD (EG,USA)
Oral and Maxillofacial Surgery Dept.
College of Dentistry, Dammam University, KSA. .

2. Unannounced Quiz
What is the LA?
 The lipid solubility determine the……….
 The degree of protein binding of a local
anesthetic agent determines the…………
 The pKa of LA determines
its……………


3. OBJECTIVS




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
The student shall be able to explain the signs
and symptoms of side effects, and Localized and
systemic complications , how to diagnose and the rational
of their treatment.
Systemic complications, how to diagnose and manage
Doctor factor (wrong technique) and how to avoid
Vasoconstrictor
LA
Needle
Patient factor

4. Factors influencing injection
discomfort?

The needle:
Sharp & small gauge

The syringe:
Aspirating to avoid local and systemic effects

The cartridge:
Smooth bung to avoid judder and allow steady injection

The solution:
Temperature: >15 – 37< is not detected by the patient.
pH: (LA with VC is acidic (3.2)…..Painful, LA without VC is
less acidic (6.8)……….Painless
Rate of injection: faster injection is painful.

5. Complications of LA

Causes:
•
•
•
•
•
Doctor factor (wrong technique)
Vasoconstrictor
LA
Needle
Patient factor

6. Complications of LA
I. Localised
II. Systemic
I. Localised complications:



Pain: during and postinjection
Failure A
Equipment failure:


Broken needle
Cartridge failure.

Neurological problems:



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Prolonged altered
sensation
Unilateral facial nerve
paralysis
Visual disturbances
Aural disturbances
Extensive paralysis:
reversed flow to the brain

7. Needle Breakage
Causes

Unexpected movement

Small needle size

Bent needles

Defective needles

8. Needle Breakage
Prevention

Use large needles

Use long needles for deep injection,>18mm

Never insert to hub

Redirect only when adequately withdrawn

9. Rush Hour, Venice

10. Needle Breakage
Management

Remain calm

Don't explore

Have the patient keep opening wide

If the needle is out remove it

Refer to an Oral Surgeon

12. Localised complications:

Vascular problems:
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

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
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Intravascular injection
Haematoma
Sloughing of oral mucosa
Self-inflicted trauma
Trismus: due to bl. & LA
Infection
Interference with wound
healing: adrenaline & dry
socket

13. Failure anaesthesia
•
Causes
•
Wrong technique
Anatomical variations:
•
•
•
•
•
•
•
•
•
Bifid or double nerve supply
Nerve anastomosis
Secondary supply by a soft tissue nerve: LN, LBN & GPN
Inadequate dose
Sepsis
acidity
Injection in BV
Anxiety
reduced patient pain threshold
Patient immaturity

14. Management of failed local
anaesthesia
•
•
•
•
•
Check anatomical landmarks
Repeat injection
Consider alternate or additional technique
Consider whether anxiety may be contributory
Settle pain and inflammation and try again about
a week later

15. Pain on Injection
Causes

Dull needles

Rapid deposit of solution

Needles with barbs

Careless technique

16. Pain during injection




Pain during injection:
Intraepithelial injection leading to ballooning
Subperiosteal injection cause discomfort due to
injection into noncompliant tissues
Too rapid injection a rate of 30 sec. per cartridge
is ideal

17. Pain on Injection
Prevention

Careful technique

Sharp needles

Topical anesthetic

Slow injections

Room temperature solutions

18. Burning on Injection
Causes

PH of solution

Rapid injection

Contamination

Warmed solutions

19. Persistent Anesthesia
or Paresthesia
Causes

Trauma to nerve

Neurolytic agents (alcohol, phenol)

Intraneural injection

Hematoma

20. Persistent Anesthesia
or Paresthesia
Management

Patient counseling and reassurance

Documentation

Follow-up

21. Trismus
A motor disturbance of the trigeminal nerve
precipitating or resulting in spasm of the
muscles of mastication

22. Trismus
Causes

Trauma to muscles or blood vessels

Contaminated anesthetic solutions

Hemorrhage

Infection

Excessive anesthetic volume

23. Trismus
Prevention

Sharp needles

Proper care and handling of cartridges

Aseptic technique and clean injection site

Atraumatic insertion

Minimal injections and volume

24. Trismus
Management
 Examination
 Conservative therapy
Passive ROM therapy
Analgesics
Heat
Muscle relaxants





25. Hematoma
Due to needle accidentally penetrate a b.v. leading to effusion of
blood into extravascular spaces
Prevention

Care with needle placement

Minimize number of injections

Don't probe with needle

Modify technique
o
short needles
o
penetration depth
o
When hematoma is large prescribe antibiotics to prevent
infection

26. Infection
Causes

Needle contamination

Improper handling of armamentarium

Infection at injection site

Improper handling of tissue

Not following technique of asepsis

27. Infection
Prevention

Disposable needles

Proper care of equipment

Aseptic technique

29. Infection
Management

Usual sign is trismus

Trismus persists (1-3 day resolution )

Antibiotics, if suspicious

30. Cartridge failure
L A cartridge may fail when subjected to high
pressure during intraligamentary or palatal
injection
 To prevent this rate of injection should be slow


31. Sloughing of Tissue
Causes

Topical anesthetic

Prolonged ischemia
Management

Observation

Documentation

32. Lip Chewing
Management

Analgesics

Antibiotics

Saline rinses

Lip lubricants

33. Facial Nerve Paralysis
Cause
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Injection into the parotid capsule
Anesthesia of peripheral Facial nerve branches
Temporal
Zygomatic
Buccal
Mandibular
Cervical

34. Facial Nerve Paralysis
Prevention

Bone contact when injecting

Avoid over penetration

Avoid arbitrary injection

35. Facial Nerve Paralysis





Management
Reassure patient
Cornea care
Documentation
Consider deferring dental care

36. Dolomite Mountains,

37. Complications of LA
Systemic adverse effects complications:





Toxicity (due to LA & VC)
 Methaemoglobinaemia:
 General NS toxicity
 Cardiovascular Toxicity (Haemoglobin contains iron in
Ferric not Ferrous state leading
Drug interactions
to poor oxygenation and
Allergic effects
cyanosis (Treated by IV 1%
Fainting/syncope
methylene blue 1.5 mg/kg. oIdiosyncrasy
toluidine (oxidise Iron) is a
metabolic product of Prilocaine.
Articaine, Benzocaine?

38. SYSTEMIC COMPLICATION
Fainting




or syncope
Fainting or syncope frequently occurs because of
patient frightened at the thought of receiving an
injection
Predisposing factors:
1-Psychogenic factors: fear , anxiety and sight
of unpleasant object as blood or surgical instrument
2-Non-psychogenic: factors as pain especially sudden
unexpected, sitting in waiting area for a long period,
hunger causing low glucose supply or exhaustion
,poor physical condition

39. Fainting
Clinical features
1-Pre-syncope period :
The patient feels faint and may feel nauseating.
Paleness and coldness of hand, cold sweating
over the forehead and hands, hypotension ,
tachycardia and deep irregular respiration

40. Syncope
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Loss of consciousness:
Hypotension , bradycardia and shallow irregular
respiration. Possible muscular twitches (tremors) or
convulsive movements of the extermities.
Progression may occur into muscular relaxation and
apnoea
2-Post-syncope period
After regaining consciousness the patient feels weak,
nauseating and mentally confused for few minutes.

41. Patho-physiology

Stress causes

Management
secretion of adrenalin into the circulation this
cause peripheral vascular resistance and blood flow to the
muscle to prepare body to response to this stressful condition
1-Stop any dental procedure
2-Place patient in supine or trendelenberg position to facilitate
venous return to the heart
3-Maintain patient airway , respiratory stimulants by aromatic spirit
of ammonia
4-Oxygen administration might be needed
5-Keep the patient in this position under observation
6-For persistent bradycardia give atropine 0.4 mg i.v

42. LA Toxicity
LA Toxicity
Manifestations and management
Manifestations and management
Prevention

43. Cause of Overdose Levels
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Total dose is too large
Absorption is too rapid
Intravascular injection
Biotransformed too slowly
Eliminated too slowly

44. Manifestations and management of LA
toxicity a
Manifestations
•Mild toxicity:
Talkativeness, anxiety,
slurred speech, confusion
Moderate toxicity:
Stuttering speech,
nystagmus, tremors,
headache, dizziness, blurred
vision, drowsiness
Management
• Stop administration of all local
anaesthetics
• Monitor vital signs
• Observe in office for 1 hr
• Stop administration of all local
anaesthetics
• Place in supine position
• Monitor vital signs
• Observe in office for 1 hr.

45. Manifestations and management of LA toxicity b
Manifestations Management
Sever toxicity:
seizure, cardiac
dysrhythmia or
arrest.
• Place in supine position
• If seizure, protect from nearby objects and
suction oral cavity if vomiting occurs
• Have someone summon medical assistance
• Monitor vital signs
• Administer oxygen
• Start IV
• Administer diazepam 5-10 mg slowly or
midazolam 2-5 mg slowly
• Institute BLS if necessary
• Transport to emergency care facility

46. General Principles
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No drug exerts a single action
No drug is non-toxic
Potential toxicity is user dependent
Adverse Drug Reactions
Side effects
Overdose

47. Adverse Drug Reactions
Altered recipient

Disease process

Emotional disturbances

Genetic aberrations

Idiosyncrasy

48. Idiosyncrasy Reaction
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

Unexplained by any known mechanism of the
drug’s action
Neither overdose nor allergic reaction
Unpredictable; treat symptoms

49. Predisposition - Overdose
Patient factors

Age

Weight

Sex

Medications

50. Predisposition - Overdose
Drug factors

Rate of injection

Vascularity of site

Vasoconstrictors

51. Adverse Drug Reactions
Allergic reaction
 Immediate - anaphylaxis
 Delayed - contact dermatitis
 Not dose related
 May be systemic or localized
 Unrelated to pharmacological effects
 Exaggerated immune system response

52. Intravascular Injection
Occurrence varies with type of injection:
Nerve Block
% positive aspirate
 Inf. alveolar
11.7
 Mental/Incisive
5.7
 Post. sup. alv.
3.1
 Ant. sup. alv./ Buccal
<1

53. Prevention

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Use aspirating syringe
Use needle - 25 ga or larger
Aspirate in 2 planes
Inject slowly

54. Vasoconstrictor Overdose
Clinical manifestations:

 Sharply elevated BP (systolic)

 Fear, anxiety

 Tenseness

 Restlessness

 Tremor

 Weakness

Throbbing headache
Perspiration
Dizziness
Pallor
Respiratory difficulty
Palpitations
Increased heart rate

55. Management - v/c overdose
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Stop dental treatment
Sit patient up
Reassure patient, administer O2
Monitor BP and pulse until fully recovered

56. Allergic Reactions
Type Mechanism Time Clinical Example
I Antigen induc. sec/min Angioedema,
Anaphylaxis
IV Cell mediated 48 hrs
Contact dermatitis

57. Allergens in Local
Esters - usually to the Para-amino-benzoic-acid
product
 Na bisulfite or metabisulfite - found in
anesthetics as perservative for vasoconstrictors
 Methylparaben - no longer used as perservative
in dental cartridges


58. Management of Allergy Pts.

If the patient gives a history of allergy to local
anesthetics - Assume that an allergy exists

Elective procedures
Postpone until work-up is completed

59. Allergy - signs/symptoms
Dermatologic:

Urticaria - wheals, pruritis

Angioedema

Minor rash

60. Allergy - signs/symptoms
Respiratory:

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Laryngeal edema
Bronchospasm
distress, dyspnea
anxiety , cyanosis or flushing
wheezing , tachycardia
diaphoresis is the state of perspiring profusely, use of
accessory muscles

61. Anaphylactic shock
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


Anaphylactic shock is anaphylaxis associated with
systemic vasodilation which results in
low blood pressure. It is also associated with severe
vasoconstriction of the bronchioles to the point where
the individual is unable to breathe
Smooth muscle spasms (GI crampy abdominal pain,
diarrhea, and vomiting )
Respiratory distress shortness of breath, wheezes or
stridor
Cardiovascular collapse

62. Management of Reactions
Delayed skin reaction
Benadryl - 50 mg stat & Q6H X 3-4 days
Immediate skin reaction

Epinephrine 0.3 mg IM or SC

Benadryl - 50 mg IM

Observation, medical consultation

Benadryl - 50 mg Q6H X 3-4 days

63. Management of Reactions
Bronchial constriction

Semi-erect position, O2 - 6 L/min

Inhaler or Epinephrine 0.3 mg IM or SC

Benadryl - 50 mg IM

Observation, medical consultation

Benadryl - 50 mg Q6H X 3-4 days

64. Mangement of Reactions
Laryngeal edema

Place supine, O2 - 6 L/min

Epinephrine 0.3 mg IM or SC

Maintain airway

Benadryl - 50 mg IV or IM

Hydrocortisone - 100 mg IV or IM

Perform Cricothyrotomy

65. Management of Reactions
Anaphylaxis

Place supine, on flat surface

ABCs of CPR, call for medical help

Epinephrine 0.3 mg IV or IM (Q 5 mins)

O2 - 6 L/min, monitor vital signs

Benadryl and Hydrocortisone

66. Methemoglobinemia





Methemoglobinemia (hemoglobin in Fe3+ oxidation
state)
1. Amide-type agents (lidocaine, prilocaine)
2. Toxic metabolite (aromatic amine)
3. Cyanosis (brown blood, blue skin color)
4. Antidote: methylene blue

67. References
1.
2.
SF Malamed: Pain and anxiety control for
the conscious dental patient, 1997.
Meechan, et al., Hand book of local
anaesthesia, 1998.

69. Suggested maximum dosage of local
anaesthetics
Drug
Common
brand
Concentration
Percentage
Maximum
number
of 1.8 ml
cartridges
Lidocaine
Xylocaine
2%
10
Lidocaine +
Epin.
Xylocaine with
epinephrine
2% lidocaine
1:100000 epinephrine
10
Mepivacaine
Carbocaine
3%
6
Mepivacaine +
norad.
Carbocaine with
neo-cobfrin
2% mepivacaine
1:20000 levonordefrin
8
Prilocaine
Citanest
4%
6
Bupivacain +
Adren.
Marcaine with
epinephrine
0.5% bupivacaine
1: 200 000
10
Etidocaine
Duranest with
1.5% etidocaine
15

73. Church of Selva Di Cadore, Colle Santa Lucia