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OS & Pain Management > Local Anesthesia pt. 4 > Flashcards

Local Anesthesia pt. 4 Flashcards

1
Q

Armamentarium
Local anesthesia delivery system

A

Syringe + Needle + Cartridge = delivery
vehicle

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2
Q

Types of Syringe
(4)

A

 Nondisposible syringes
 Disposable syringes
 “Safety” syringes
 Computer-controlled local anesthetic delivery system

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3
Q

 Nondisposible syringes (5)

A

• Breech-loading, metallic, cartridge-type, aspirating
• Breech-loading, plastic, cartridge-type, aspirating
• Breech-loading, metallic, cartridge-type, self-aspirating
• Pressure syringe for PDL injection
• Jet Injector (“needleless” syringe)

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4
Q

 Breech-loading:

A

 cartridge is inserted into the syringe from the side

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5
Q

 Aspirating:

A

 with harpoon, it engages thick silicone rubber stopper
at the tail end of the cartridge
 Negative pressure will cause blood (if there) to be
visible in the cartridge

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6
Q

 Positive Pressure:

A

 Thumb ring forces solution through needle to patient

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7
Q

Self-aspirating Syringes

A

Popularity of this syringe decrease.
Notion occur that aspiration is not as
reliable with the self aspirating

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8
Q

Pressure Syringe

A

Possible to achieve consistently reliable
pulpal anesthesia of one isolated tooth in
the mandibular arch

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9
Q

Jet Injector

A

 1947 Figge and Scherer introduced
“needle-less” injection
 Basis
 Liquids forced through very small openings called jets, at very
high pressure can penetrate intact skin or mucous membrane
 Primary use for Jet is to obtain topical anesthesia before
needle insertion
 Example: mucosal anesthesia of palate
 One still need nerve block and infiltration……….☻
 Jet injector is NOT an adequate substitute for needle
and syringe.
 Lastly, it cost US $630 - $1595 !!!

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10
Q

Disposable Syringe
 Advantages
(3)

A

 Disposable, single use
 Sterile until opened
 Lightweight

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11
Q

Disposable Syringe
Disadvantage
(2)

A

 Does not accept prefilled
dental cartridges
 Difficult Aspiration
(usually need two hands)

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12
Q

Safety Syringes
(3)

A

 Needle sheathed to prevent needle-stick injury
 Recommend use of safety syringe system
 Disadvantage is Cost

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13
Q

Computer-Controlled Local
Anesthesia Delivery System

A

 Constant flow rate of
local anesthesia

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14
Q

Controlled rate of fluid
administration =

A

reduced pain
perception

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15
Q

Care for Your Instruments

A

Wash the syringe after each use
Dismantle and lubricate every 5 autoclavings
Clean Harpoon with brush after use
Replace piston and harpoon on regular basis

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16
Q

The needle

A

 Stainless steel and disposable

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17
Q

Anatomy of needle

A

 Bevel, shaft, the hub, and cartridge penetrating end
 Shaft has two important factors
• Diameter (gauge)
• Length (from tip to the hub)
 Greater angle the bevel, greater the degree of deflection

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18
Q

Gauge

A

 Diameter of the lumen of the needle
 Smaller the gauge #, Greater the diameter
• Example 25-gauge has greater internal than 30-gauge internal diameter

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19
Q

 Word on the street:
 Smaller diameter (higher number gauge) needles are
less traumatic to the patient than needle with large
diameter………
 This assumption is unwarrnated !!!
 Hamburg (1972) demonstrated that patient is unable
to differentiate among 23-, 25-, 27-, and 30-gauge
needle.
 Bottom line:

A

 Patients feel the same regardless of gauges of needle

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20
Q

Advantage of Larger Gauge Needle
(5)

A

Less deflection, as needle advances
through tissues
Greater accuracy in injection
Less chance of needle breakage
Easier aspiration
No perceptual difference in patient comfort

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21
Q

Larger-gauge needles should be used when there is a
greater risk of

A

positive aspiration

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22
Q

Red: – gauge
Yellow: – gauge
Blue: – gauge

A

25
27
30

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23
Q

Deflection of needle will differ according to

A

gauges

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24
Q

 Deflection becomes important when

A

needle
must penetrate a greater thickness of tissue

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25
Q

Conventional Dental Needle
Needle tip is at the

A

lower edge of the needle shaft

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26
Q

Nondeflecting Needle
(2)

A

 The tip of needle is at the center of the shaft
 But over years of use, dentists become
accustomed to deflecting needle

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27
Q

Birotational Insertion Technique

A

 Rotate handpiece or
needle in a back-and-
fore rotational
movement while
advancing the needle

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28
Q

Length
 Dental needle length
(2)

A

 Long and short

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29
Q

Average short needle is —

A

20mm

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30
Q

Average long needle is —

A

32mm

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31
Q

Weakest portion of the needle is at the

A

hub

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32
Q

Needles should not be inserted into tissues to their hub unless it is

A

absolutely necessary for the success of the injection

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33
Q

Handling of Needle

A

Never used on more than one patient
Change after 3 or more tissue penetration
Must cover in protective sheath when not
use
Pay attention to the position of uncovered
needle tip
Proper disposal is necessary
 Recapping using “Scoop” technique

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34
Q

Problems
(2)

A

 Pain on insertion
Breakage

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35
Q

Pain on insertion

A

Dull needle

36
Q

Breakage

A

 Do not bent needle if to be inserted into >5mm soft tissue depth
• Most commonly “bent needle” procedures are
 Inferior alveolar nerve block
 Posterior superior alveolar nerve block
 Intrapulpal injection
 PDL injection and Intraosseous injection
• According to Malamed
“ there is no injection technique used in dentistry that
mandates that the needle be bent for the injection to be
successful”

37
Q

Problems
Don’t change — of a needle when
its embedded in tissue

A

direction

38
Q

Pain on withdraw may caused by
“—” barb on the tip

A

fishhook

39
Q

Malamed recommended using – or at
least –gauge needle

A

25
27

40
Q

33 cases of broken needle that went to
litigation + 27 reported cases

A

 59 of 60 broken needle situations, they were
30-gauge short or ultrashort
 Only one case involved with 27-gauge short
needle

41
Q

The glass cylinder can hold — of solution

A

2ml

42
Q

U.S. dental cartridge contains — of local
anesthetic solution

A

1.8ml

43
Q

Dental cartridge is commonly referred as

A

“carpule”
 Actually a registered trade name by Cook-Waite lab
(1920)

44
Q

Some cartridge are made of — in
stead of glass

A

plastic cylinder
 Plastic cylinder isn’t able withstand extended force
and will leak

45
Q

Components of a Cartridge
(3)

A

Stopper (Plunger)
Universal Color coding around the cylinder
Aluminum cap

46
Q

Stopper (Plunger)
(2)

A

 Receives the harpoon of the aspirating
syringe
 Plunger is made of silicone

47
Q

Aluminum cap
 Holding —

A

diaphragm

48
Q

Diaphragm

A

 Semipermeable membrane (latex rubber)
 Where needle penetrates into the cartridge
• Possibility of latex allergy exist
 Shojaei and Haas
• “there are no reports of studies or cases in which a
documented allergy was due to the latex component of
cartridges for dental anesthesia”

49
Q

Mylar plastic label wrap around glass cylinder

A

Protect doctor and patient in event of glass crack or
shattering

50
Q

Cartridge Contents
— is the main player !!

A

Local anesthetic drug

51
Q

Cartridge Contents
May have Vasopressor
(2)

A

 Sodium bisulfite (antioxident)
 Sodium bisulfite oxidize to Sodium bisulfate

52
Q

Cartridge Contents
NaCl

A

 make solution isotonic with tissue

53
Q

Cartridge Contents
(5)

A

Local anesthetic drug is the main player !!
May have Vasopressor
NaCl
Distilled water
Removal (1984) of methylparaben
(bacteriostatic agent)

54
Q

Care and Handling
 No manufacturer claim of sterility about

A

exterior surface
of the cartridge
 Bacterial culture tested fail to produce any growth

55
Q

Care and Handling
Cannot withstand extreme temperature

A

 No autoclaving especially plastic cartridge
 When heated, vasopressors are destroyed

56
Q

Care and Handling
Store in room temperature in a

A

dark place
 Study showed no benefit of using cartridge warmer

57
Q

Care and Handling
Do NOT

A

soak cartridge in alcohol or “cold sterilizing
solution”
 Semipermeable diaphragm permits diffusion of these solution
 Read the drug package insert

58
Q

Problems
Bubble in the cartridge

A

 Small bubble 1-2 mm are usually nitrogen gas
 Large bubble with extruded stopper

59
Q

Problems
Extruded Stopper

A

 >2mm bubble due to frozen cartridge
 If no bubble, may caused by diffusion of other agent through diaphragm
• Wescott demonstrated measurable alcohol in cartridge after only one day of immersion in alcohol solution

60
Q

Problems
Corroded Cap

A

 If immersed in disinfecting solution
 Only sterilization needed are
• 91% isopropyl alcohol
• 70 % ethyl alcohol

61
Q

Problems
Rust on the Cap

A

 Rust from “tin” container

62
Q

Problems
Leakage during injection

A

 Eccentric needle puncture of diaphragm

63
Q

Problems
Broken Cartridge

A

 Return damaged boxes upon receiving
 Shatter cartridge occurs due to improper
loading
 Bent harpoons

64
Q

Problems
Burning on injection

A

 pH, alcohol, heat, expiration date..

65
Q

Recommendations

A

 Dental cartridges must never be used on more
than one patient
 Cartridges should be stored at room
temperature
 It is not necessary to warm cartridges before use
 Cartridges should not be used beyond their
expiration date
 Cartridges should be checked carefully for
cracks, chips and integrity of the stopper and
cap before use

66
Q

Topical antiseptic (optional)

A

 Betadine
 Chlorhexidine

67
Q

Topical anesthetic

A

 Placed directed with applicator for 1 min
• Gill and Orr showed 10 to 15 sec topical treatment has the effect as placebo
• Stern and Giddon demostrated topical to mucous membrane for 2-3 mins leads to profound soft-tissue analgesia
 Benzocaine > Lidocaine topical (reduced overdose potential)
 Off label use of EMLA but its biter
 Unmetered spray is not recommended

68
Q

Additional Armamentarium (5)

A

Topical antiseptic (optional)
Topical anesthetic
Applicator sticks
Cotton Gauze
Hemostat

69
Q

Most undesirable reaction to local
anesthesia are — to the act of
drug administration

A

responses

70
Q

Most common psychogenic reactions
(2)

A

 Vasodepressor syncope
 Hyperventilation

71
Q

other induced reaction
(3)

A

• Tonic-clonic convulsions
• Bronchospasm
• Angina pectoris

72
Q

Medical History Questionnaire
Update every

A

6 months

73
Q

Medical History Questionnaire
Allergy

A

 True, documented, and reproducible allergy to
amide is virtually nil
 Epinephrine allergy most likely due to
exaggerated physiological response

74
Q

Medical History Questionnaire
Bleeding problems (Coagulopathies)

A

 Avoid techniques with ↑ chance of +
aspiration
• Use supraperiosteal, PDL, Intraosseous

75
Q

Medical History Questionnaire
Heart Failure

A

 CHF with disability (ASA III or ASA IV) may
demonstrate ↓ liver perfusion ↑ t ½ amide
local anesthesia

76
Q

Medical History Questionnaire
 ASA IV cardiovascular risk pt is not a candidate
for vasopressors or elective dental care

A

 Recent (< 6 months) or repeated MI increases risk
during dental care or local injection

77
Q

Medical History Questionnaire
— use of vasopressors in L.A. is not
contraindicated in stable angina
(Unstable angina = ASA IV)

A

Judicious

78
Q

Medical History Questionnaire
 — according to AHA
 AIDS, Hepatitis A,B, Jaundice… ↑ t ½ amide

A

Prophylaxis

79
Q

Medical History Questionnaire
 Seizure

A

 Causes
• Stress / Anxiety
• Hypoglycemia
• Hyperventilation
 Stress Reduction protocol is needed

80
Q

Medical History Questionnaire
Pregnancy

A

 Relative contraindicated especially at 1st trimester
 Consultation with OB-GYN is needed

81
Q

— ↑ t ½ of circulating local
anesthesia

A

Cimetidine

82
Q

Cimetidine ↑ t ½ of circulating local
anesthesia
(2)

A

 H2 receptor blocker compete with lidocaine
for hepatic oxidative enzyme
 Cimetidine + ASAIII CHF = relative
contraindication for amide local anesthesia

83
Q

Tricyclic Antidepressant (TCAs)

A

 Enhance cardiovascular action to
exogenously administered vasopressors
• 5 -10 X increase with levonordefrin and Nore-epi
• 2 X increase with epinephrine
 What’s the big deal ?!
• Hypertensive crisis death

84
Q

Cocaine stimulate nore-epi release and inhibit reuptake
 Tachycardia / hypertension ↑ myocardio O2 requirement Cardiac ischemia MI
 72 hrs is needed for Cocaine clearance
 Dental correlation:

A

 Epinephrine-impregnated gingival retraction cord is absolutely contraindicated in the cocaine abuser
 Postpone dental treatment, if suspected cocaine usage within 24 hours

85
Q

Relative Contraindication with local
anesthesia

A

 Malignant Hyperthermia
 Methemoglobinemia (to Prilocaine)

OS & Pain Management (8 decks)

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