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LOCAL LOCAL ANAESTHESIAANAESTHESIA
INDIAN DENTAL ACADEMY
Leader in continuing dental education www.indiandentalacademy.com
www.indiandentalacademy.com
Contents Contents
HistoryArmamentariumDefinition &ClassificationComposition Different Agents , Vasoconstrictors Mechanism of ActionBio Transformation Systemic Action
INTRODUCTIONINTRODUCTION
‘No pain no gain’Ancient time – dental treatment associated with painEarliest pain relief – Coca shrub mood elevator Incas
Cocoa shrub – foot hills of AndesIntroduced by Europeans to South AmericaCocaine
1855 – Gaedicke extracted alkaloid Erythroxylin
1860 – Dr. Scherzer cocaine from this alkaloid
1844 – Francis Rynd (Dublin) Acetate of morphine + Creosote Skin incision TGN treatment First time liquid used - intradermally
1884 – marks birth of LA
Sigmund Freud Carl Koller Cocaine for eye operation
William Steward Halsted Cocaine for inferior dental nerve
1886 – BDJ William Alfred Hunt et al Cocaine - dental anesthetic documented
1901 – E Mayers Vasoconstrictor + cocaine
1905 13 lives claimed – addiction A Einhorn & E Uhlfelder(Sweden)
Synthesized Procaine hydrochloride Procaine sterilizable, non-additive, non-toxic
1943 N Lofgren(Sweden)
Synthesized Anilide called Lignocaine Lignocaine – amide linked synthetic derivative
1946 – Lignocaine introduced Dental practice
1948 – Lignocaine ; published in BDJ – Lofgren
Sweden – Birth place of newer LA agents
Bupivacaine
Ropivacaine
Pain and pain controlPain and pain control
DEFINITION -- It is defined as an unpleasant emotional
experience usually initiated by a noxious stimulus and transmitted over a specific neural pathway to the central nervous system where it is interpreted as such.
Methods of pain control.Methods of pain control.
Accupuncture Analgesia -- Originated-CHINA,between600BC to 200AD
Hypnotism – Still employed—susceptible patients, Time consuming, lasts for less time
Audio Analgesia – 1959 Gardner and licklider Loud noise used to produce analgesia
Electric analgesia -- Peripheral nerve- Direct electric current Elos-1,powered by 18v battery- Siemens Never more than 30 ma
Analgesia by Cold air– Inability to conduct AP at low tempr Nondolar-French-60 lts/min-Cold air Dis adv-Mucosa dry, Cotton stick to mucosa,ulcers-if not
moistened.
ArmamentariumArmamentarium
Syringe- Breech loading, metallic cartridge-aspirating
AdvantageVisible cartridge
Aspiration- 1 hand
Autoclavable
Rust resistance, Long lasting
DisadvantageWeight
Size-Too big
Possibility of infection
PISTON WITH HARPOON
FINGER GRIP
THUMB RING
SYRINGE BARRELNEEDLE ADAPTOR
Breech loading plastic cartridge-aspirating
AdvantageLight weight
Cartridge visible
Rust resistance, Long lasting
Low cost
DisadvantageSize – Too big / small
Possibility of infection
Repeated autoclaving – Plastic looses its properties
PLASTIC REUSABLE SYRINGE
Breech loading metallic cartridge-Self aspirating
AdvantageCartridge visible
Autoclavable
Easier to aspirate
Piston is scored – Qty Known
DisadvantageWeight
Possibility of infection
Finger has to be moved from thumb ring to disc-Aspiration
Takes time to accustom
SELF ASPIRATING SYRINGE
Pressure syringe --
AdvantageMeasured dose
Overcomes tissue resistance
Non threatening – Cartridge protected
DisadvantageCost
Inject too rapidly -Possibility
PRESSURE SYRINGE
WILCOX- JEWETT OBTUNDER
Jet injectors
AdvantageDoes not require – needle
Very small volume – Delivered
Topical anesthesia-effective
DisadvantageInadequate – Pulpal / Regional block
Patient disturbed by jolt of jet.
Cost
PDL damage – common
JET INJECTOR
Disposable syringe
AdvantageSingle use
Sterile-Till opened
Light weight
DisadvantageDoes not accept – Dental cartridge
Aspiration – Difficult – 2 hands
Needle Type – Stainless steel – Disposable
Platinum
Iridium platinum
Ruthenium platinum Parts – Bevel
Shank
Hub-Leur lock, Friction grip.
Gauge –23 (IM) – Length 23 mm 25 (D) – Length 36/26 mm - +ve asprn
Blood – 100% 27 (D) – Length 27 mm - +ve asprn Blood – 87% 30 (D) – Length 22 mm - +ve asprn Blood – 2-5%
Cartridge—
Consists of -- Cylindrical glass tube
Stopper
Aluminum cap
Diaphram
Rubber diaphragm
Aluminum capNECK
GLASS TUBE
RUBBER PLUNGER
Additional Armamentarium – Topical antiseptic
Topical anesthetic
Cotton Gauge
Hemostat
Applicator Stick.
Definition of L.A --Definition of L.A --
It is defined as a transient loss of sensation to
a painful or potentially painful stimulus, resulting
from a reversible interruption of peripheral
conduction along a specific neural pathway to its
central integration and perception in the brain.
Classification--Classification--
Based on composition – A) Natural – eg – cocaine. B) synthetic nitrogenous compd – para amino benzoic acid-procaine, benzocaine. acetanilide - lignocaine quinoline - cinchocoline C) non Nitrogenous compounds -
benzyl alcohol D) miscellaneous – clove oil , phenol .
Based on intermediate group --
Esters –Benzoic acid Para Amino benzoic Acid
Butane Chloroprocaine
Cocaine Procaine
Benzocaine Propoxycaine
Hexylcaine
Tetracaine
Amides – Articaine
Bupivacaine
Dibucaine
Lignocaine
Mepivacaine
Prilocaine
According to biological site and mode of action— Class A Class B
Class C
Class D
Agents acting at receptor site –external surface.
Agents acting at receptor site- internal surface..
Agents acting at receptor independent physico chemical mechanism.
Agents acting in combn of receptor and independent mechanism.
Biotoxin -eg tetrodotoxin
Quaternary amonium-scorpion venom
Benzocaine
Clinically useful agents –Lignocaine etc
Injectables -- Surface -- Ultra short acting *Soluble - eg <80 min eg Lignocaine Cocaine Lignocaine Short acting 45-50 *Insoluble- egMin 2% ligno with Benzocaine1:1 lakh VC Medium acting 90-1502% ligno with Vc or4% prilocaine with 1:2 epin Long acting > 180 5% Bupivacaine with 1:2 epin
Composition--Composition--
Local anesthetic drug –eg lignocaine .
Vasopressor drug - eg adrenaline.
Preservative - eg Sodium meta bi sulfide.
Germicide – eg methyl paraben.
For isotonicity – Normal Saline .
Distilled water to equal the desired amount .
Individual Agents --Individual Agents --
Lignocaine-- Classified under – Amide 2-diethylamino 2,6 acetoxylidide hcl 1943 – Nils Lofgrens- intro 1948(dentistry) Metabolised- Liver by microsomal fixed function
oxidases to monoethyl glycerine and xylidide Excretion -<10% unchanged, >80%-metab Vasodilaton ->Procaine, <Mepivacaine Pka –7.9 , ph(plain)-6.5,ph(with Vc)5 –5.5,Onset of
action 2-3 min,Anesthetic half life 1.6hrs,topical anesthetic -yes
NH.CO.CH2.N
CH3
CH3
C2H5
C2H5
LIGNOCAINE
Recommended dose – 7mg/kg not>500mg with VC 4.4mg/kg not>300mg For children with VC 3.2 mg/kg Council for dental therapeutics- ADA 4.4mg/kg It is non allergic available in three formulations Ligno2% with out Vc Ligno2% with VC 1:80,000 Ligno2% with VC 1:100,000 Adverse reactions- CNS stimulation then Depression,Overdose
causes unconsciousness and respiratory arrest.
Bupivacaine –Classified under amide
1-butyl 2,6 pipecoloxylidide
Toxicity <4 times – Lignocaine, Mepivacaine
Metabolism –Liver by Amidases
Excretion by kidney (16% unchanged)
Vasodilation- relatively significant
Pka-8.1,ph(plain)- 4.5-6, ph(vc)- 3-4.5
Onset of action –6-10 min,Anesthetic half life-2.7hrs,Dose
1.3mg/kg ,Maximum dose-not >40mg,Absolute maximum dose-not> 90mg
N
NH.CO
C4H9
CH3
CH3
BUPIVACAINE
Available as 0.5% soln 1:2,00,000 (vc)
Indicaton- pulpal anesthesia->90- min.
Full mouth recontruction.
Extensive perio surgery.
management of post op pain.
Duration –Pulpal- 90- 180 min
Soft tissue-4-12 hrs
Contra indication- burning sensation at site of injecton, in children-anticipating self
trauma .
Procaine- Classified under –Esters
2Diethylamino ethyl 4aminobenzoate hcl
Metabolised-in Plasma by plasma pseudocholine esterases
Excretion >2%unchanged, 90% -PABA,8% diethyl aminoethanol
in urine.
Pka-9.1,High degree of vasodilation, 2% procaine 15-30min soft
tissue LA
no pulpal anesthesia , > incidence allergy, drug of choice for intra
arterial injection and accidents.
Mepivacine- classified -amide type
1 Methyl 2,6 pipecoloxylidide hcl
Metabolism-microsomal fixed funcn oxidasea in liver.
Maximum dose 4.4 mg/kg , absolute max dose-300mg.
Excretion-1-10% unchanged urine.
Pka-7.6,Anesthetic half life-90min,
Mild vasodilator, 3% mepivacaine used in patients with vc
contraindicaton. Low reported cases-allergy.over dose CNS
stimulation followed by depression.
Articaine- classified- Amide 2 Carboxymethoxy 4 methylthiophene hcl Metabolised- Liver Excretion – Kidney 10% - unchanged. Pka 7.8, Anesthetic half life-1.2-2 hrs, Maximum dose – 1mg/kg , Absolute maximum dose –
500mg first LA Agent with thiophene ring,little potential to
diffuse through soft tissue. Adverse reaction-methymoglobinemia-Rx by using
methylene blue 1mg/kg.
Etidocaine- classified –Amide
Metabolism –Liver
Excretion –urine- Kidney
Pka 7.7 ,Anesthetic half life-56 min.
Maximum dose 8mg /kg, Absolute max dose 400 mg
Employed mainly in epidural or caudal regional block.
VASOCONSTRICTORSVASOCONSTRICTORS
Added – to counteract vasodilation effect of injectable L.A Decreases rate of absorption Reduces the risk of overdose reaction Increases duration of action Reduces bleeding at the site
CLASSIFICATION OF V.CCLASSIFICATION OF V.C
Catecholamines EpinephrineNor epinephrineDopamine
Non catecholaminesAmphetamineMeta amphetamine
Based on chemical stc (Catechol nucleus)
Based on mode of actionDirect acting Epinephrine Nor epinephrine
Indirect acting Amphetamine Tyramine
Mixed acting Ephedrine
Proprietary name
Mode of action
Systemic 1) CVS
EPINEPHRINEAdrenaline
α1& β receptors
Systolic & Diastolic pressure Heart rate Oxygen consumption Stroke volume
FELYPRESSINOctopressin
Direct stimulation of vasculatureNo direct effect onMyocardium Non-arrythmagenicHigh doses – impaired coronary flow
2) CNS
3) RS4) Vasculature
5)Metabolism
CNS stimulation
Bronchodilator α1 – vasoconstrictionβ 2 – vasodilation oxygen consumption blood sugar level
Adrenergic nerve – no effect
Vasoconstriction – coronary blood vessels
Anti-diuretic action Oxytocin like action – uterus
6) Clinical
application
7) Max
dose
8) Side
effect
Allergy, hemostasis
0.2 mg – healthy
0.04mg – CVS impaired
CVS & CNS symptoms
Cerebral hemorrhage
As vaso-constrictor in
L.A
0.04mg
MECHANISM OF ACTIONMECHANISM OF ACTION
Resting membrane potential Excitation of nerve
Stimulus – slow depolarization – electric potential less negative increase in permeability to Na
Electric potential – critical level – firing / threshold potential Rapid depolarization – reversal of electric potential Reaches peak +35 mv - +40 mv rapid depolarization
(0.3msec) Repolarize to RMP -60 to –70mv (0.7msec)
Conduction / propagation Depolarization – 1segment – local current affects
RMP next segment Current flow +ve –ve; never backwards – prevented by
previous unexcitable refractory segm.
Spread Sequential depolarization - non myelinated Saltatory conduction – myelinated – faster & energy
efficient
Rate Non-myelinated 1.2m/s Myelinated 14.8 – 120m/s
Site of action Outer bimolecular lipoprotein layer in nerve membrane
MODE OF ACTIONMODE OF ACTION
Altering the basic RMP of nerve
Altering the threshold potential
Decreasing the rate of depolarization
Prolonging rate of repolarization
THEORIES OF ACTION OF THEORIES OF ACTION OF L.AL.A
ACTEYLCHOLINE THEORY: Involved in nerve conduction in addition to its role as a
neurotransmitter at nerve synapses No such evidence
CALCIUM DISPLACEMENT THEORY: L.A causes nerve block by displacement of Ca from some
membrane site that controls entry of Na Varying conc. Of Ca in nerve – not seen
SURFACE CHARGE THEORY: Action by binding to nerve membrane and changing its
electric potential. Cationic molecules aligned at membrane water interface –
surface elec potn more positively charged - electric potn , threshold potn.
Demerits- RMP not altered by LA. LA act on nerve channel rather than surface –cannot
explain how uncharged LA molecule causes nerve blockage.
Membrane expansion theory- LA lipid soluble – enters nerve membr and changes
configuration of membr. There by reduced space for sodium to enter and thus cause inhibition.
Explains how non ionised drug causes- blockade, nerve membrane do expand and become more fluid when exposed to LA .
No evidence to tell that the whole blockade is due to this phenomenon.
Specific receptor theory— LA act by binding to specific receptors- sodium channel-
on external/ axoplasmic surface. Once it binds there is no permeability of sodium- no
conduction.
LA molecule replace calcium molecule at calcium gate –
thus prevent sodium entry.
This is by far the most accepted theory.
Mechanism of actionMechanism of action..
All LA are available as acid salt of weak bases.
Weak base(BNHOH) combined with acid (HCL) to give
acid salt(BNHCL)& water.
In mucosa BNHCL dissociates into BNH and CL . Normal
tissue PH 7.4 is necessary for conversion of acid salt to free base.
BNH which is hydrophilic further dissociates to BN and
H. BN is now lipophilic.
Lipophilic BN diffuses through nerve membrane (lipid).
Inside the nerve it combines with intrinsic H. (H in nerve
formed by buffering action.)
Newly formed ionised BNH displaces calcium from the
sodium channel receptor site to cause conduction
blockade.
LA Solution .
Biotransformation. Biotransformation.
Esters- eg- Procaine-
hydrolyzed to pseudo cholinesterase's
Para amino benzoic acid Diethyl amino alcohol
Excreted unchanged urine further transformed-urine
Atypical cholinesterase's --- increase toxicity
Amide eg lidocaine --Mono ethyl xylidide
Glycine xylidide xylidide
Xylidide
Hydroxy xylidide. Excreted kidney .Significant renal diseases – contra indication.
Systemic action.Systemic action.
CNS – Low levels – no action Toxic dose – tonic clonic convulsionsBlood- 0.5-4.0 mg/ml-no complication 4.5-7.0 mg/ml-pre seizure sign/ symptom >7.5mg/ml-tonic clonic seizures.Anti convulsive property –As it causes depression of CNS.Seizure threshold- excitability nerve
CVS- Action on Heart
Electrical excitability of myocardium .
conduction rate
Tone of contraction.
clinically effective level-1.8-5mg/ml –anti arrhythmic
used in premature ventricular contractures , arrhythmias.
Action on vasculature- normal value no change. over dose- hypo tension.( myocardial
contractility) Lethal dose- cardio vascular collapse
( myocardial contractility, massive peripheral vaso dilatation )
Action on Respiratory system– Normal levels- no over dose- bronchial muscles
relaxation . Over dose – Respiratory arrest due to CNS depression.
QueryQuery
Least toxic LA- 2 chlorprocaine.Most toxic LA- tetracaine- for topical-dicyclomineIf allergic to LA –diphenhydramine- anti histamine + mild anestheticFor children - 2 chlorprocaineLA is added with bi carbonate in infections Allergy – delt in detail part II
Ideal requirements- its action must be reversible Must be non irritant and not produce any secondary
irritation Low degree of systemic toxicity Must be potent enough Have sufficient penetrating properties
LOCAL LOCAL ANAESTHESIAANAESTHESIA
part IIpart II
www.indiandentalacademy.com
Techniques of InjectionTechniques of Injection
Basic points- Use a Sterile Sharp Needle
Check The flow of Solution
Determine Whether to Warm soln before use or not.
Position the patient
Dry the tissue/ wipe once.
Apply topical anesthetic
Topical antiseptic /optional Communicate with patient apply firm hand rest Inject few drops of soln, communicate with patient, Advance to the target slowly ,aspirate , inject Withdraw the needle slowly Observe the patient & check for anesthetic symptoms
Technique for Maxillary Technique for Maxillary BlockBlock
Supra periosteal injection:
Anaesthetize buccal soft tissue & hard tissue
Nerves anaesthetized – large terminal branches
Indication :
1 or 2 teeth need to be anaesthetized / small area
Contra-indication : Infection
Dense bone covering
Target area : Behind apices of tooth
Landmarks : Muco-buccal fold
Crown & root length
Posterior Superior Alveolar Nerve Block Area anaesthetized:
Maxillary 3rd, 2nd & 1st molar (except mesio-buccal root of 1st molar
Bone & periodontium over these Indication:
Treatment of 2 or more molars required Supra-periosteal injection – ineffective Acute inflammation
Contra-indication: Pt with bleeding disorders
Disadvantage: More of soft tissue landmarks used 2nd injection for 1st molar
Landmarks: Mucobuccal fold Zygomatic process of maxilla Infratemporal surface of maxilla Anterior border and coronoid process of mandible Tuberosity of maxilla
Complications:
Hematoma –
Non visible - pterygoid plexus posteriorly
Visible – buccal aspect
Accidental mandibular Anaesthesia
Orbital contents – anaesthetized accidentally
Accidental - parotid gland facial nerve affected
Anterior superior alveolar nerve block Areas anaesthetized
Pulp of maxillary C.Is – Canine Buccal periodontium, lower eyelid, lateral aspect of nose Upper lip
Indications More than 2 anterior teeth
Contraindications Discreet treatment areas Hemostasis of localized area – not adequately achieved
Landmarks Mucobuccal fold, infra-orbital notch, infra-orbital foramen
2 methods:
Intra-oral Premolar approach
Incisal approach
Extra-oral
Palatal AnaesthesiaPalatal Anaesthesia
Pressure Anaesthesia Slow deposition Small quantity Effect only a very small area
Greater palatine nerve block Areas anaesthetized
Palatal soft tissue – posterior aspect Palatal hard tissue
Indication Surgical procedures posterior portion of hard palate Palatal Anaesthesia in conjunction with posterior superior
alveolar nerve block. Landmarks
Greater palatine foramen – junction of the maxillary alveolar process & palatine bone
Between the 2nd & 3rd molars – 1-1.5cms away from gingival margin
Nasopalatine nerve block Areas anaesthetized
Anterior portion of Hard palate and over lying structures back to the bicuspid area.
Indications Anterior palatal procedures supplementing infraorbital nerve
blocks Anaesthesia of nasal septum
Landmarks Central incisor & incisive papilla
Complications Hematoma Necrosis
Technique Single needle penetration Multiple needle penetration
Usually most discomforting block for patient – very painful
Maxillary nerve block Areas anaesthetized
Pulpal Anaesthesia Maxillary teeth – 1 side Periodontium / soft tissue – 1 side
Indications Extensive oral / periodontal / endodontal procedures Other regional nerve blocks not possible Therapeutic procedure to diagnose neuralgias
Contra-indications Pediatric patients Infection / inflammation Hemorrhage – anticipated Greater palatine canal approach not possible – bony obstr.
Landmarks Mucobuccal fold distal to maxillary 2nd molar Maxillary tuberosity Zygomatic process Greater palatine foramen
Complications Hematoma Penetration into orbit
Volume – displaces orbital structures, periorbital swelling, proptosis, 6th nr block – diplopia, transient loss of vision, optic nerve blocked, retrobulbar block / hemorrhage, opthalmoplegias (common)
Penetration into nasal cavity Patient complains – LA running down the throat – to prevent
keep mouth wide open Technique
High tuberosity approach Greater palatine canal approach
Maxillary nerve block – Extra Oral Areas anaesthetised
Anterior temporal & zygomatic region Lower eyelid Side of nose Anterior cheek Upper lip Maxillary teeth / alveolar bone & overlying structures – 1side Hard & soft palate Tonsils – parts of pharynx Nasal septum – floor of nose
Indications Extensive surgery – 1 half of maxilla Others blocks not possible Therapeutic purposes
Technique mid point of zygomatic process Needle gently contact lateral pterygoid plate Maximum length of 4.5cms directed slightly upward & forward
Note: In final position – internal maxillary artery – inferior to needle Temporal vessels on either sides Posteriorly foramen ovale with mandibular nerve & foramen
spinosum with middle meningeal artery Anteriorly pterygomaxillary fissure
Mandibular Nerve BlocksMandibular Nerve Blocks
Inferior alveolar nerve block Areas anaesthetised
Mandibular teeth upto midline Body of mandible Inferior portion of ramus Buccal periosteum & mucous membrane Lingual soft tissue Anterior 2/3rd of tongue
Indications Multiple mandibular teeth – procedures Buccal / Lingual soft tissue anaesthesia
Contraindications Infection / acute inflammation Young children / mentally handicapped
Landmarks Coronoid notch Pterygomandibular raphe Occlusal plane of posterior mandibular teeth
Complication Hematoma Trismus Transient facial paralysis (parotid gland)
Anatomical structures - final position Superiorly –
Inferior alveolar nerves & vessels Insertion of medial pterygoid Mylohyoid nerves & vessels
Anteriorly – Deep part of parotid gland
Laterally – Lingual nerve Internal pterygoid Spehnomandibular ligament
Medially- ramus of mandible.
Closed mouth/ Akinosis technq— Area anesthetized
one half of mandible upto mid line including lingual tissue. Land mark-
occluding plane of the teeth. Muco gingival junction maxillary teeth. Antr border of ramus.
More popular now Land marks easy One prick – mandibular, buccal, lingual n anesthetised. Patient more comfortable.
Gow gates technique– 1973. deposit soln at neck of condyle Area –all mandibular hard and soft tissue Upto mid line. Land marks-
antr border of ramus, tendon of temporalis, corner of mouth, inter tragic notch of ear and exter nal ear.
Final position needle is just inferior to condyle.and insertion of lateral pterygoid.
Gained popularity – single needle penetration, relies on soft tissue landmarks – differ from patient to patient
Lingual nerve block – Area anaesthetised –
Anterior 2/3rd tongue, floor of mouth, lingual mucoperiosteum Only used singly to operate on tongue, floor of mouth
Buccinator / long buccal nerve block Area anaesthetised –
Buccal mucosa & mandibular molar – mucoperiosteum Land marks
External oblique ridge, retromolar triangle
Mental nerve block
Areas anaesthetised Lower lip, mucous membrane – anterior to mental foramen
Landmarks Mandibular bicuspids
Indications Surgery of lower lip or mucous membrane
Extra Oral TechniqueExtra Oral Technique
Mandibular nerve Area anaesthetised
Temporal region with auricle of ear & external auditory meatus TMJ, salivary glands Anterior 2/3rd of tongue Mandible – hard & soft tissue – midline
Landmarks mid point of zygomatic arch Zygomatic notch Cornoid process of mandible Lateral pterygoid plate
Indications
When need to anaesthetise entire mandibular nerve
Infection / trauma – makes terminal anaestheisa not possible
Diagnostic / therapeutic
The needle is pointed posteriorly & to a greater depth of
5 cms
Mental & Incisive nerve block Area anaesthetised
Mandibular hard & soft tissue – labial aspect with lower lip Landmarks
Bicuspid teeth, lower ridge of body of mandible Supra & infra orbital notch Pupil of the eye
2 inch 22 gauge needle used & introduced slightly anteriorly & downwards
ComplicationsComplications
Definition An anaesthetic complication may be defined as any
deviation from the normal expected pattern during or after securing regional anaesthesia
2 types Local Systemic
LOCAL COMPLICATIONS Needle breakage Pain on injection Burning on injection Persistent anaesthesia or paresthesia Trismus Hematoma Sloughing of the tissue / soft tissue injury Facial nerve paralysis
SYSTEMIC COMPLICATIONS
Toxicity
Idiosyncracy
Allergy
Anaphylactoid reaction
Syncope
Classification Primary / secondary
Primary – caused & manifested at time of anaesthesia Secondary – manifested later
Mild / severe Mild – exhibit slight change from normal expected pattern
- reverses itself without treatment Severe – manifests itself – pronounced deviation
- requires specific treatment
Transient / permanent Transient – is one that is severe at occurrence – no residual
effects Permanent – residual effect; lasts for a life time even though it
is mild
Complications could be a combination of any of the above mentioned types
Majority are either Primary Mild & Transient or Secondary Mild & Transient
Complications
Attributed to solutions – toxicity, allergy, idiosyncrasy,
anaphylactoid reaction, local irritation
Attributed to technique / needle – syncope, muscle
trismus, pain, edema, hematoma
Needle breakageNeedle breakage
Cause – Unexpected movement – patient (if patient movement is
opposite to path of needle insertion) Usually at Hub – Magill forceps – hemostat used If needle has penetrated soft tissue – not usually more
than few mms deep – encased in scar tissue in few weeks – removed later on if necessary
Multiple used needle
Prevention Correct gauge – 25 gauge Long needles – prevent penetration till hub Not to redirect when in tissue
Management Patient – not to move – hand in the mouth – mouth open Fragment visible – remove it Fragment not visible – inform patient – not necessary for
intervention immediately – Radiograph suggested
Precautions
Avoid bony contact
Avoid heavy pressure
Avoid movement of needle and patient
Pain on injectionPain on injection
Causes – Careless injection technique Multiple used needle Rapid deposition
Problems – Pain – patient anxiety – unexpected movements
Prevention – Proper technique – sharp needles Enter topical anaesthetics Inject slowly – solution sterilized Check temperature of solution
Burning on injectionBurning on injection
Causes Due to pH of solution 5 (LA) – 3 (LA+VC) Rapid injection Contamination Warm solution
Problems pH disappears upon LA action – no residual
sensitivity Contaminated solution other complications – trismus,
edema, paraesthesia
Prevention
Slow injection – 1ml / minute
Cartridge stored at room temperature – away from
containers with alcohol / other agents
Persistent anaesthesia / Persistent anaesthesia / paresthesiaparesthesia
Causes Direct trauma to nerve – bevel of needle LA solution containing neurotoxic substance – alcohol Injection of wrong solution Hemorrhage / infection – near to nerve
Problem Persistent anaesthesia – usually rare Biting / thermal / chemical insult – without patient
awareness When lingual nerve is involved – taste impaired
Prevention Proper care & handling of dental cartridge Adherence to injection protocol
Management Usually resolve in 8 weeks Periodic recall & check up of patients Persistence – consult neurosurgeon LA – not to be injected in the same region
Trismus Trismus
Definition “difficulty in opening the jaws due to muscle spasm”
Causes Trauma – muscle / blood vessel Irritating solution – hemorrhage LA have been known to have slight myotoxicity Excessive volume – distension of tissues
Problems Pain / hypomobility
Prevention
Use of sharp, sterile, disposable needle
Aseptic technique
Practice atraumatic methods
Avoid repeated injections
Use minimum volume
Management Heat therapy
Warm saline rinses, moist hot packs Analgesics
Aspirin, Codeine (30-60mg) Initial physiotherapy
Thrice a day Antibiotic regime
Possibility of infection
HematomaHematoma
Causes Arterial & venous puncture – common in PSA & Inf Alv
nerve blocksProblem Bruise – may / may not be visible extraorally Complications – pain & trismus Swelling & discolouration
Prevention Knowledge of normal anatomy – proper technique Shorter needle – PSA, minimise the number of
penetration
Management Immediate – apply firm pressure 5-10minutes
Inf Alv Nr. Block – medial aspect of ramus Infra orbital, Mental, Incisive block – directly over foramen PSA – pressure on soft tissue with finger as posteriorly as
tolerated by patient – medial superior direction
Patient to be reviewed after 24 hours, advice analgesics, cold application upto 4-6 hours, heat application next day
Infection Infection
Comparitively rare complication
Instrument needle solution to be as aseptic as
possible
Area & operative hands – cleaned
Avoid passing needle through infected area
Edema Edema
Causes Trauma during injection Infection, hemorrhage Allergy (Angioedema) Injection of irritating solution
Problems Pain & dysfunction Airway obstruction
Prevention Proper care & handling of armamentarium Atraumatic injection technique Complete medical evaluation prior to injection
Management Trauma – resolve in few days without therapy Hemorrhage – resolve slowly 7-14 days Allergy – life threatening, airway impairment – basic life support,
call medical help, Epinephrine – 0.3mg, Antihistamine, Corticosteroids
Total airway obstruction – Tracheostomy / Cricothyroidectomy
Sloughing of tissueSloughing of tissue
Causes Epithelial desquamation – topical anaesthesia – long
time, heightened sensitivity to LA Sterile abscess – secondary to prolonged ischemia – VC
in LA site – hard palate Problems Pain & infection
Prevention Topical – for not more than 1-2 minutes VC – minimal concentration in solution
Management
Symptomatic – pain – analgesia
Epithelial desquamation – resolve few days
Sterile abscess resolve 7-10 days
Soft tissue injurySoft tissue injury
Causes Trauma occurs – frequently mentally / physically
challenged children Primary cause – significantly longer duration of action
Problem Pain & swelling Infection of soft tissue
Prevention Cotton roll between lip & teeth Patient – guarded against eating / drinking
Facial nerve paralysis Facial nerve paralysis
Cause LA solution into parotid gland – usually while giving Inf
Alv Nr. Block, Akinosis technique
Problem Ipsilateral loss of motor control – Buccinator muscle Inability to raise the corner of Mouth, close Eye lid
Prevention Needle tip to contact bone, redirection of needle to be
done only after complete withdrawl
Management Reassure the patient Eye patches to the affected – eye drops Contact lenses if any – removed
Some post anaesthetic extra oral lesions – recurrent apthous stomatitis, herpes simplex seen in susceptible patient
Mixture of Diphenhydramine, milk of magnesia – relief against ulcers
Systemic complications Systemic complications
Toxicity / toxic overdose Caused by overdose reaction – increased conc. In blood Predisposing factors
Age – any age Weight – greater the body weight greater is the amount of dose
tolerated before overdose reaction Sex – during pregnancy – renal function disturbed – females
more affected at this time Diseases – hepatic & renal dysfunction reduced breakdown Congestive heart failure – less liver perfusion Genetics – pseudocholinesterase deficient – toxicity - Ester LA
Mental attitude and environment – pyschological attitude affects response to various stimuli – larger dose LA needed
Fearful patients – lower seizure threshold for LA Drug factors – Vasoactivity – vasodilation – increase in blood Concentration – greater concentration – greater risk Dose smaller dose should always be preferred Route of Administration – Intravascular – increased toxicity Rate of injection – slower rate preferred Vascularity of injection site – more vascular – greater
absorption Presence of Vasoconstrictor – with VC less absorption
Causes of toxicity – Biotransformation usually slow Drug – slowly eliminated by kidney Too large a total dose Absorption from injection site - rapid Accidental intra-vascular injection
Symptoms – CNS – cerebral cortical stimulation – talkative, restless,
apprehensiveness, convulsions Cerebral cortical depression – lethargy, sleepiness,
unconsciousness Medullary stimulation – increased B.P, Pulse rate, Respiration
Medullary depression – mild fall in B.P– severe cases drops to 0 , Pulse , Respiration – similar effect
Treatment Mild overdose reaction – slow onset reaction – > 5 mins
administer Oxygen (prevent acidosis), monitor vital signs, in case of convulsions – anti-convulsants
Slower onset - >15 mins – same procedure Severe overdose reaction – rapid onset – 1 minute –
unconsciousness with or without convulsion, patient in supine position, convulsions – protect hand, leg, tongue, BLS, administer anti-convulsant ----------- post seizure – CNS depression usually present
Idiosyncrasy Idiosyncrasy
Any reaction neither toxic nor allergic
Common cause – some underlying pathology /
psychological
Pyschotherapy may be helpful
Treatment – symptomatic
Syncope Syncope
Anxiety – increased blood supply to muscles, sitting
position 2mm Hg, less pressure – cerebral arteries
Clinically light headedness, dizziness, tachycardia
& palpitation – may further lead to Unconsciousness
Treatment – discontinue procedure, supine position,
deep breathing, BLS
AllergyAllergy 1 % of all reaction in, LA is allergy
Predisposing factors Hyper sensitivity to ester more common-procaine Most of patients allergic to methyl paraben Recently allergy to sodium meta bi sulfide is also
increasingPrecautions--- Ho of allergy to be recordedHo any asthmatic attack to be noted.Always better to test the patient for allergy before
treatment.
Consultation and allergy testing Refer doubtful cases for allergic skin test – sub cutaneous test
most sensitive. Informed consent that includes cardiac arest end death to be
included. Signs and symptoms of allergy.
Dermatological------ urticaria –wheal and smooth elevated patch seen, ------angio oedema—localised swelling – face hands, common
Respiratory– broncho spasm, respiratory distress, dysnea, wheezing, flushing, tachycardia etc.
Laryngeal edema – type of angio neurotic oedema- life threating.
Edema upper air way – laryngeal edema Lower air way affect broncioles- small.
Management `skin reactions-
Delayed – non life threatening - oral histramine blockers- 50 mg diphenhidramine
Immediate reaction—with conjunctivites rhinitis- vigerous managemennt.
0.3 mg epinephrine. IM 50 mg diphenhydramine Im medical help summoned.
Observe patient for minimum of 60 min Oral histamine blockers for 5 days. Respiratory reaction –
patient in comfortable position. administer - oxygen Admn epinephrine- bronchodilator Observe for 60 min , advise anti histamines to prevent relapse.
Laryngeal edema- Patient position ,oxygen, broncho dilator, oral anti histamines. If condition not improving cricothyrotomy - achieve patent
air way if necessary give artificial ventilation.
Patient with confirmed allergy status- if patient allergic to any one type of anesthetic ester /
amide use the other. Use histamine blocker like diphenhydramine as
anesthetic. General anesthesia alternative method of pain control –
electric anesthesia / hypnosis.
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