GARY J. WAYNE DMD DIPLOMATE AMERICAN BOARD OF ORAL/MAXILLOFACIAL SURGERY BOYNTON ORAL &...
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Transcript of GARY J. WAYNE DMD DIPLOMATE AMERICAN BOARD OF ORAL/MAXILLOFACIAL SURGERY BOYNTON ORAL &...
GARY J. WAYNE DMD
DIPLOMATE AMERICAN BOARD OF ORAL/MAXILLOFACIAL SURGERYBOYNTON ORAL & MAXILLOFACIAL
SURGERY AND DENTAL IMPLANT CENTERBOYNTON BEACH, FLORIDA
Local Anesthesia
HOW DO LOCAL ANESTHETICS WORK?WHAT ARE THE IMPLICATIONS IN MY
CHOICE OF ANESTHETICS?
Review of Neurophysiology
Summary
Local anesthetics dissociate into the ionic form in order to penetrate the nerve membrane. Anesthetics are available as salts clinical use.
Pka-the ability to dissociate into the ionic form in a given ph
The ph of a nerve is quite stable. The ph of the extracellular fluid is variable
The ph of a local anesthetic (and the surrounding tissue into which it is injected) greatly influences its nerve blocking action.
Ph of normal tissue is 7.4, ph of an inflamed area is 5 to 6
Summary
Local anesthetics containing epinephrine or other vasoconstrictors are acidified by manufacturers to inhibit oxidation of the vasopressor
The acidification causes more “burning” on injection
Ph of solutions without epinephrine are around 5.5, with epinephrine 3.3
Clinically this lower ph is more likely to produce a burning sensation, as well as a slightly slower onset of action
Summary
Increasing the ph (alkalinization) of a local anesthetic solution speeds the onset of its action, increases its clinical effectiveness, and makes its injection more comfortable
However, the local anesthetic base, because it is unstable, precipitates out of alkanized solutions, and this makes these solutions ill suited for clinical use
Adding sodium bicarb to the anesthetic solution immediately prior to injection provides greater comfort and a more rapid onset of anesthesia
Amides Esters
ArticaineBupivacaineDibucaineEtidocaineLidocaineMepivacainePrilocaine
ButacaineCocaineBenzocaineHexylcainePiperocaineTetracaine
Local Anesthetics
Esters Others
PABA Type Chloroprocaine Procaine Propoxycaine
Quinoline CentbucridineDiphenhydramineSaline
Local Anesthetics
Amide Local Anesthetics
Lidocaine “Xylocaine”Mepivacaine “Carbocaine”Prilocaine “Citanest”Articaine “Septocaine”Bupivacaine “Marcaine”
Lidocaine
Available since 1943, most commonAvailable with/without vasoconstrictorWith 1:100,000 Epi Max dose 7mg/kg not to exceed 500mgPulpal Anesthesia 60minSoft Tissue Anesthesia 3-5hrPka 7.9 Onset of action 2-3 minutes
Mepivacaine 3 %
Common for non-surgical proceduresUsed in pediatrics and geriatricsOnset of action 1.5-2 minutesSlight Vasodilation < LidocainePulpal Anesthesia 20-40 minutesSoft Tissue Anesthesia 2-3 hoursPka 7.6Maximum dose 6.6mg/kg not to exceed
400mg
Mepivacaine 2% with vasoconstrictor
1:20,000 Neo-Cobefrin/Levonordefrin1/5 Vasoconstrictor ActivityRapid onset 1.5-2 minutesSoft Tissue/Pulpal Anesthesia Similar to
Lidocaine with vasoconstrictorMaximum Dose 6.6mg/kg not to exceed
400mgIs available with 1:100,000 epi (documented
lidocaine allergy)
4% Prilocaine
Vasodilation >Mepivacaine,<LidocainePka 7.9Onset 2-4 minutesDuration Pulpal 10min infiltration, 60 min
blockMaximum Dose 6mg/kg not to exceed 400mg
4% Prilocaine with 1:200,000 epi
Rapid Biotransformation Safest of all amides Good for “epi sensitive” patients requiring
prolonged pulpal anesthesia >60minDuration of action pulpal 60-90min, soft
tissue 3-8hrsMaximum Dose 6mg/kg not to exceed 400mg
4% Articaine with 1:100,000 epi
Newest “wonder anesthetic” in U.S.Pka 7.8Onset of action 2-2.5 minutes block,1-2
minutes infiltrationClaim is that can diffuse more readily,
controlled comparisons failed to corroborateDuration of action pulp 60-70 min, soft tissue
3-6hrsMaximum dose 7mg/kg not to exceed 500mgAvailable 1:200,000 epi
.5% Bupivacaine
1:200,000 epiGood for lengthy procedures as an
adjunct/post operative analgesia“Weak” anestheticPka 8.1Onset of action 6-10 minutesMaximum dose 1.3mg/kg not to exceed 90mgDuration pulpal 90-180 min, soft tissue 4-9hrs
(12hr reported)
Esters
Can Use with documented allergy to AmidesProcaine+Propoxycaine“2 %” Procaine Provides 30-60 min of pulpal 2-3 hours of soft tissue each cartridge 7.2 mg of Propoxycaine 36mg of ProcaineMaximum dose 6.6mg/kg
Vasoconstrictors
EpinephrineNeo CobefrinLevonordefrinLevophed
When to use/not use
Discussion:Cardiovascular disease“allergy”PediatricsElderlyPost operative analgesiaHemostasis
Vasoconstrictors
“Vasoconstrictors should be included in local anesthetic solutions unless specifically contraindicated by the medical status of the patient or by the duration of the planned treatment”
S.Malamed
Local Complications
Needle Breakage Pain on Injection Burning on Injection Persistent Anesthesia or Paresthesia Trismus Hematoma Infection Edema Sloughing of Tissues Soft Tissue Injury Facial Nerve Paralysis Post Anesthetic Intraoral Lesions
Systemic Complications
Overdose
Overdose
Patient Factors Age Weight Other Drugs Sex (pregnancy) Presence of Disease Genetics Mental Attitude and enviroment
Overdose
Drug Factors Vasoactivity Concentration Dose Route of Administration Rate of Injection Vascularity of the Injection Site Presence of Vasoconstrictors
Overdose
“Many local anesthetic overdose reactions occur as a result of the combination of inadvertant intravascular injection and too rapid rate of injection, both of which are virtually 100% preventable”
S. Malamed
Minima/Moderate Overdose Levels
SignsTalkativeness ApprehensionExcitability Slurred SpeechGeneralized Stutter EuphoriaDysarthria NystagmusSweating VomitingFailure to follow commands DisorientationLoss of response to pain ^Blood Pressure^Heart Rate ^Respiratory Rate
Minimal/Moderate Overdose Levels
Symptoms (progressive with increasing blood levels)
Light-Headedness and dizziness RestlessnessNervousness NumbnessSensation of twitching, before observed Metallic
TasteVisual Disturbances Auditory
DisturbancesDrowsiness and disorientation Loss of
consciousness
Moderate/High Overdose Levels
Tonic-Clonic seizure activity followed byGeneralized CNS DepressionDepressed blood pressure, heart rate, and
respiratory rate
Management of Mild Overdosage>5min
Reassure patientO2 via nasal cannula or hoodMonitor and record vital signsIV if ableSelf Limiting, discharge when recovered
Mild Overdose-Slower Onset>15min
Biotransformation trouble All of the previous methods plusAnticonvulsantSummon medical assistancePatient to be examined by physician or
hospital
Severe Overdose
BLSAnticonvulsantTerminate treatmentSummon Help
Epinephrine Overdose
More common in gingival retraction cordSymptomsFear,Anxiety Respiratory difficultyTenseness PalpitationsRestessness PallorThrobbing Headache DizzinessTremor WeaknessPerspiration
Epinephrine Overdose
Signs of epinephrine overdose Sharp elevation in blood pressure, systolic Elevated heart rate Possible cardiac dysrhythmias
(PVC,Vtach,Vfib)
Management of Epinephrine Overdose
Terminate procedurePosition patient –Semisitting or erect Minimized CNS EffectMonitor Blood PressureAdminister O2 (except hyperventilation)Recover-Most are self limiting
Allergic Reactions
Rare with amidesSeen with topical anesthetics-estersSodium metabisulfites-only with vasoconstrictorsTreatment BLS Oral Histamine Blocker Sub Q epi IM Histamine Blocker Bronchial Treatment Laryngeal Treatment
Maxillary Anesthesia
Field BlockInfiltrationNerve BlockIntraseptalIntraosseousPeriodontal Ligament
Infiltration
Area of treatment is flooded with local anesthesia
Periodontal treatment Selective restorative procedures
Field Block
Anterior SuperiorMiddle SuperiorPosterior Superior
Nerve Blocks
Maxillary (Second Division) Junction of Vertical/Horizontal Shelves Second Molar Long Needle 2cc of solutionGreater Palatine NasopalatineInfra-orbital
Infraorbital
Problems with Maxillary Anesthesia
FewRelated to inflammation/infectionPosterior teethUse Nerve Blocks Infraorbital-Extra/Intra Oral Nasopalatine Secondary Division
Mandibular Anesthesia
Mandibular Anesthesia
Inferior Alveolar Block
80-85% SuccessfulRelated to Greater Density of Bone Limited Accessibility Wide Variation of Anatomy Solution Depot within 1mmMost Important BlockVariationsAccessory Innervation
Inferior Alveolar Block
Deepest Part of Ascending RamusParallel to Occlusal PlaneLateral To RapheHit bonePull Back?Bevel aimed away, assist in needle deflection
and direction of liquid
Accessory Innervation
Determine Objective Anesthesia of IANMylohyoidAccessory ForaminaCervical Branches
Mental Nerve Block
Does not anesthetize incisive branchAngle needle anteriorSecond PremolarHigh risk of nerve injury
Buccal Nerve Block
Bevel Toward BoneDistal and buccal to most distal molar
Gow-Gates
Anesthetizes all branches IAN,lingual,mylohyoid,mental, incisive
auriculotemporal and buccalHigh Success >95%Low AspirationParallel tragus to anterior border of ramusMesiolingual cusp of maxillary second molarHit neck of condyle and back off 1mmStay open 1-2 minutes-bite block
Gow-Gates Target
Vazirani-Akinosi Closed Mouth Block
IAN, Incisive, Mental, Lingual and MylohyoidMucogingival of Maxillary Third or Second
MolarParallel Maxillary Occlusal PlaneMedial of Anterior RamusApproximate 25mm (midway)
Supplemental Aids
Ligamentary InjectionsIntraosseous InjectionsIntrapulpalElectronicHypnosisNitrous OxideIV/General Anesthesia Always reduces local anesthesia“Gizmos”