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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
Conventional Dental Needle Needle tip is at the
lower edge of the needle shaft
26
Nondeflecting Needle (2)
 The tip of needle is at the center of the shaft  But over years of use, dentists become accustomed to deflecting needle
27
Birotational Insertion Technique
 Rotate handpiece or needle in a back-and- fore rotational movement while advancing the needle
28
Length  Dental needle length (2)
 Long and short
29
Average short needle is ---
20mm
30
Average long needle is ---
32mm
31
Weakest portion of the needle is at the
hub
32
Needles should not be inserted into tissues to their hub unless it is
absolutely necessary for the success of the injection
33
Handling of Needle
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
34
Problems (2)
 Pain on insertion Breakage
35
Pain on insertion 
Dull needle
36
Breakage
 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
Problems Don’t change --- of a needle when its embedded in tissue
direction
38
Pain on withdraw may caused by “---” barb on the tip
fishhook
39
Malamed recommended using -- or at least --gauge needle 
25 27
40
33 cases of broken needle that went to litigation + 27 reported cases
 59 of 60 broken needle situations, they were 30-gauge short or ultrashort  Only one case involved with 27-gauge short needle
41
The glass cylinder can hold --- of solution
2ml
42
U.S. dental cartridge contains --- of local anesthetic solution
1.8ml
43
Dental cartridge is commonly referred as
“carpule”  Actually a registered trade name by Cook-Waite lab (1920)
44
Some cartridge are made of --- in stead of glass
plastic cylinder  Plastic cylinder isn’t able withstand extended force and will leak
45
Components of a Cartridge (3)
Stopper (Plunger) Universal Color coding around the cylinder Aluminum cap
46
Stopper (Plunger) (2)
 Receives the harpoon of the aspirating syringe  Plunger is made of silicone
47
Aluminum cap  Holding ---
diaphragm
48
Diaphragm
 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
Mylar plastic label wrap around glass cylinder 
Protect doctor and patient in event of glass crack or shattering
50
Cartridge Contents --- is the main player !!
Local anesthetic drug
51
Cartridge Contents May have Vasopressor (2)
 Sodium bisulfite (antioxident)  Sodium bisulfite oxidize to Sodium bisulfate
52
Cartridge Contents NaCl
 make solution isotonic with tissue
53
Cartridge Contents (5)
Local anesthetic drug is the main player !! May have Vasopressor NaCl Distilled water Removal (1984) of methylparaben (bacteriostatic agent)
54
Care and Handling  No manufacturer claim of sterility about
exterior surface of the cartridge  Bacterial culture tested fail to produce any growth
55
Care and Handling Cannot withstand extreme temperature
 No autoclaving especially plastic cartridge  When heated, vasopressors are destroyed
56
Care and Handling Store in room temperature in a
dark place  Study showed no benefit of using cartridge warmer
57
Care and Handling Do NOT
soak cartridge in alcohol or “cold sterilizing solution”  Semipermeable diaphragm permits diffusion of these solution  Read the drug package insert
58
Problems Bubble in the cartridge
 Small bubble 1-2 mm are usually nitrogen gas  Large bubble with extruded stopper
59
Problems Extruded Stopper
 >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
Problems Corroded Cap
 If immersed in disinfecting solution  Only sterilization needed are • 91% isopropyl alcohol • 70 % ethyl alcohol
61
Problems Rust on the Cap
 Rust from “tin” container
62
Problems Leakage during injection
 Eccentric needle puncture of diaphragm
63
Problems Broken Cartridge
 Return damaged boxes upon receiving  Shatter cartridge occurs due to improper loading  Bent harpoons
64
Problems Burning on injection
 pH, alcohol, heat, expiration date..
65
Recommendations
 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
Topical antiseptic (optional)
 Betadine  Chlorhexidine
67
Topical anesthetic
 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
Additional Armamentarium (5)
Topical antiseptic (optional) Topical anesthetic Applicator sticks Cotton Gauze Hemostat
69
Most undesirable reaction to local anesthesia are --- to the act of drug administration
responses
70
Most common psychogenic reactions (2)
 Vasodepressor syncope  Hyperventilation
71
other induced reaction (3)
• Tonic-clonic convulsions • Bronchospasm • Angina pectoris
72
Medical History Questionnaire Update every
6 months
73
Medical History Questionnaire Allergy
 True, documented, and reproducible allergy to amide is virtually nil  Epinephrine allergy most likely due to exaggerated physiological response
74
Medical History Questionnaire Bleeding problems (Coagulopathies)
 Avoid techniques with ↑ chance of + aspiration • Use supraperiosteal, PDL, Intraosseous
75
Medical History Questionnaire Heart Failure
 CHF with disability (ASA III or ASA IV) may demonstrate ↓ liver perfusion ↑ t ½ amide local anesthesia
76
Medical History Questionnaire  ASA IV cardiovascular risk pt is not a candidate for vasopressors or elective dental care
 Recent (< 6 months) or repeated MI increases risk during dental care or local injection
77
Medical History Questionnaire --- use of vasopressors in L.A. is not contraindicated in stable angina (Unstable angina = ASA IV)
Judicious
78
Medical History Questionnaire  --- according to AHA  AIDS, Hepatitis A,B, Jaundice... ↑ t ½ amide
Prophylaxis
79
Medical History Questionnaire  Seizure
 Causes • Stress / Anxiety • Hypoglycemia • Hyperventilation  Stress Reduction protocol is needed
80
Medical History Questionnaire Pregnancy
 Relative contraindicated especially at 1st trimester  Consultation with OB-GYN is needed
81
--- ↑ t ½ of circulating local anesthesia
Cimetidine
82
Cimetidine ↑ t ½ of circulating local anesthesia (2)
 H2 receptor blocker compete with lidocaine for hepatic oxidative enzyme  Cimetidine + ASAIII CHF = relative contraindication for amide local anesthesia
83
Tricyclic Antidepressant (TCAs)
 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
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:
 Epinephrine-impregnated gingival retraction cord is absolutely contraindicated in the cocaine abuser  Postpone dental treatment, if suspected cocaine usage within 24 hours
85
Relative Contraindication with local anesthesia
 Malignant Hyperthermia  Methemoglobinemia (to Prilocaine)

OS & Pain Management (8 decks)

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