local anesthetic

Views:
 
Category: Education
     
 

Presentation Description

No description available.

Comments

Presentation Transcript

LOCAL ANESTHETICS:

Dr.Shalini Singh 1 LOCAL ANESTHETICS

CONTENTS:

2 CONTENTS Definition History Classification Pain propagation and mechanism of action Important properties of local anesthetics Undesired effects of local anesthetics Specific local anesthetics Local aanesthetic techniques Maxillary mandibular Complication Local systemic A dvances

DEFINITION ::

3 DEFINITION : Drugs that cause reversible loss of sensory perception specially of pain in a restricted area of the body, when applied topically or local injection. LA if applied to a mixed nerve—sensory and motor impulses are interrupted—resulting in muscular paralysis and loss of autonomic control.

Common Uses Of Local Anaesthetics::

4 Common Uses Of Local Anaesthetics : Dentistry Excision Dermatology Spinal Anaesthesia

PowerPoint Presentation:

5 HISTORY

PowerPoint Presentation:

Early History Of Regional Anesthesia Koller and Gartner report local anesthesia (1884) Carl Koller 1857 -1944 6

PowerPoint Presentation:

Early History Of Regional Anesthesia Koller and Gartner report local anesthesia (1884) 1884 Halsted injects cocaine directly into mandibular nerve and brachial plexus William S. Halsted 7

PowerPoint Presentation:

Early History Of Regional Anesthesia Koller and Gartner report local anesthesia (1884) 1884 Halsted injects cocaine directly into mandibular nerve and brachial plexus 1904 Einhorn discovers procaine ( Novocaine ) Procaine 8

PowerPoint Presentation:

Early History Of Regional Anesthesia Koller and Gartner report local anesthesia (1884) 1884 Halsted injects cocaine directly into mandibular nerve and brachial plexus 1904 Einhorn discovers procaine (Novocaine) 1943 Lofgren discovers lidocaine (Xylocaine) Lidocaine 9

PowerPoint Presentation:

Chronology Of Local Anesthetics Cocaine Niemann 1860 Ester Benzocaine Salkowski 1895 Ester Procaine Einhorn 1904 Ester Tetracaine Eisler 1928 Ester Lidocaine Lofgren 1943 Amide Chloroprocaine Marks, Rubin 1949 Ester Mepivacaine Ekenstam 1956 Amide Bupivacaine Ekenstam 1957 Amide Ropivacaine Sandberg 1989 Amide After: Cartwright & Fyhr. Reg Anesth 1988;13:1-12 10

PowerPoint Presentation:

11 CLASSIFICATION

BASED ON SITE :

12 BASED ON SITE

BASED ON CHEMICAL STRUCTURE:

13 BASED ON CHEMICAL STRUCTURE

BASED ON DURATION OF ACTION:

14 BASED ON DURATION OF ACTION

BASED ON ORIGIN:

15 BASED ON ORIGIN

DIFFERENCES:

16 DIFFERENCES

PowerPoint Presentation:

17 PAIN PROPAGATION AND MECHANISM OF ACTION

Resting Membrane Potential:

Resting Membrane Potential There is an electrical charge across the membrane. The resting potential (when the cell is not firing) is a 70mV difference between the inside and the outside. 18 inside outside Resting potential of neuron = -70mV + - + - + - + - + -

PowerPoint Presentation:

19

PowerPoint Presentation:

20

PowerPoint Presentation:

21

PowerPoint Presentation:

CONDUCTION of a NERVE IMPULSE 22 Voltage gradient along axon, causing a current. This causes configurational change in Na-channels in the next segment  conduction

PowerPoint Presentation:

23

PowerPoint Presentation:

24

L A - MODE OF ACTION:

25 L A - MODE OF ACTION Blockage of membrane depolarisation in all excitable tissues, usually intended on peripheral nerve  Membranestabilizer

THEORY OF ACTION OF L.A:

THEORY OF ACTION OF L.A Specific receptor theory by strichartz 1987 Drug molecules bind to specific receptors present on the external or internal axoplasmic surface of sodium channels & by acting directly on them, decrease or eliminate permeability to Na 2+ leading to interruption of nerve conduction.

STRUCTURE OF LA:

STRUCTURE OF LA R INTERMEDIATE CHAIN N R2 R3 INTERMEDIATE CHAIN: AMIDE C O O ESTER NH C O Drug should reach Nerve through tissue HYDROPHILLIC Drug should enter Neuron ( Nerve ) LIPOPHILLIC 27

Conduction Blockade:

28 Conduction Blockade LAH + LA Ionized Nonionized

SEQUENCE OF EVENTS WHICH RESULT IN CONDUCTION BLOCKADE :

29 SEQUENCE OF EVENTS WHICH RESULT IN CONDUCTION BLOCKADE

SEQUENCE OF EVENTS WHICH RESULT IN CONDUCTION BLOCKADE :

30 SEQUENCE OF EVENTS WHICH RESULT IN CONDUCTION BLOCKADE

PowerPoint Presentation:

Ionized 31

PowerPoint Presentation:

Na + Na + 32

IMPORTANT CLINICAL PROPERTIES OF LOCAL ANESTHETICS:

33 IMPORTANT CLINICAL PROPERTIES OF LOCAL ANESTHETICS

PowerPoint Presentation:

pKa ONSET = pKa pKa = pH at which 50% of drug is ionized LA’s <50% exists in the lipid soluble nonionized form Only the nonionized form crosses into the nerve cell 34

pH influence:

35 pH influence Usually at range 7.4 -8.5 Decrease in pH shifts equilibrium toward the ionized form, delaying the onset action. Lower pH, solution more acidic, gives slower onset of action Presence of Pus and inflammation will retard the action of LA. ( probably low acidic pH) therefore LA are more ionized - don’t penetrate very well Blood flow Decreased ability of LA to produce effects

PowerPoint Presentation:

ROLE of pH and pKa in LOCAL ANESTHETICS 36

PowerPoint Presentation:

LIPID SOLUBILITY Anesthetic Potency Potency <=> lipid solubility Higher solubility <=> can use a lower concentration and reduce potential for toxicity [LA] 37

PowerPoint Presentation:

38 Lipid solubility is an important characteristic. Potency is related to lipid solubility, because 90% of the nerve cell membrane is composed of lipid. This improve transit into the cell membrane

PowerPoint Presentation:

PROTEIN BINDING DURATION OF ACTION Duration <=> protein binding Bupivacaine 95% Lidocaine 65% Procaine 6% 39

INCREASED DOASGE:

40 INCREASED DOASGE Intensity & Duration <=> INCREASED Increase dose via increased volume or concentration of LA

VASODILATOR ACTIVITY:

41 VASODILATOR ACTIVITY Affects Anesthetic potency and duration Greater vasodilator activity = increased blood flow to region =rapid removal of anesthetic molecule from injection site ; thus decreased anesthetic potency and duration.

Composition of LA Solution:

Composition of LA Solution Lignocaine Hcl --- (Anesthetic) 24.64 mg (2 %) Adrenaline --- (Vasoconstrictor ) 0.0125 mg (1:80,000) Sodium metabisulphite (Reducing Agent) 0.5 mg Methyl paraben --- (Preservative) 1 mg OR Cupryl hydrocuprinotoxin 1 mg Thymol --- (Fungicide) Salts ( NaCl ) --- ( Isotonicity ) 5-6 mg Distilled Water --- (Vehicle) 100 ml OR Ringer’s Lactate 42

NEED FOR VASOCONSTRICTOR:

NEED FOR VASOCONSTRICTOR All clinically effective injectable L.A have some degree of vasodialating activity ↑ absorption of L.A into CVS → removal from injection site Rapid diffusion of L.A from inj site → ↓ duration of action & depth of anesthesia. Higher plasma level of L.A → ↑ risk of toxicity ↑ bleeding at inj site. Addition of vasoconstrictor to L.A.. Constriction of blood vessels → ↓ tissue perfusion Slow absorption into CVS → low anesthetic blood level → ↓ risk of toxicity. Higher volume of L.A around nerve → ↑ duration of action ↓ bleeding at inj site 43

Classification:

Classification Pyrocatechin derivatives - Epinephrine & Norepinephrine Benzol derivatives - Levonordefrin Phenol derivatives - Phenylephrine Catecholamines Epinephrine, Dopamine, Isoproterenol Noncatecholamines Amphetamine, Ephedrine, Methoxamine 44

PowerPoint Presentation:

ADDITION of Sodium Bicarbonate NaHCO3 - é pH & nonionized base Speeds onset of block 1 mEq NaHCO3 per 10 ml Lido/ Mepiv .1 mEq NaHCO3 per 10 ml Bupiv 45

ACTIONS OF LA - LOCAL:

46 ACTIONS OF LA - LOCAL All LAs have effects on nerves acting via Na+ channel – sensory endings, nerve trunks, NM junctions, ganglion and receptors Sensory and Motor fibres are equally sensitive – depends on diameter and types of fibres Smaller fibers are more sensitive than larger ones Myelinated nerves are blocked earlier than non- myelinated ones Autonomic fibres are more susceptible than somatic ones Order of blockade in general: Pain – temperature – touch – deep pressure

PowerPoint Presentation:

47 UNDESIRED EFFECTS OF LOCAL ANESTHETICS

PowerPoint Presentation:

CNS – biphasic (stimulation then depression) CVS – depression Respiratory system – mild bronchodilation Clinical situation Blood level ( ug /ml) Anticonvulsive 0.5 - 4 Preseizure signs 4.5 - 7 Tonic – clonic seizures > 7.5 Clinical situation Blood level ( ug /ml) Antiarrhythmic 1.5 - 5 Myocardial depression 5 - 10 Cardio-vascular collapse > 10

CENTRAL NERVOUS SYSTEM:

CENTRAL NERVOUS SYSTEM CNS Stimulation: (More sensitive than cardiac) Dose-related spectrum of effects and All effects are due to depression of neurons First an apparent CNS stimulation ( convulsions most serious) Followed by CNS depression ( death due to respiratory depression) Premonitory signs include: ringing in ears, metallic taste, numbness around lips Cocaine - euphoria (unique in its ability to stimulate CNS) Lidocaine - sedation even at non-toxic doses 49

CARDIOVASCULAR SYSTEM :

50 CARDIOVASCULAR SYSTEM ARRHYTHMIAS : direct effect (More resistant than CNS) Decrease cardiac excitability and contractility Decreased conduction rate Increased refractory rate ( bupivicaine ) ALL can cause arrhythmias if conc. is high enough Note: cocaine is exception......it stimulates heart HYPOTENSION: Arteriolar dilation is a result of: Direct effect (procaine and lidocaine have most effect) Block of postganglionic sympathetic fiber function CNS depression Avoid by adding vasoconstrictor to the preparation Cocaine is exception: produces vasoconstriction, blocks catecholamine reuptake

METHEMOGLOBINEMIA:

51 METHEMOGLOBINEMIA Some LA metabolites have significant oxidizing properties This may cause a significant conversion of hemoglobin to methemoglobin and compromise ability to carry oxygen May be a problem if cardiopulmonary reserve is limited Treat with oxygen and methylene blue (converts methemoglobin to hemoglobin) prilocaine benzocaine lidocaine have been implicated

PowerPoint Presentation:

52 Hypersensitivity: Common with ester-linked LA Rashes, angio -edema, dermatitis and rare anaphylaxis Sometimes typical asthmatic attack Neurotoxicity: LA can cause concentration-dependent nerve damage to central and peripheral NS Mechanism(s) not clear Permanent neurological injury is rare May account for transient neurological symptoms.

PowerPoint Presentation:

53 SPECIFIC LOCAL ANESTHETICS

PROCAINE (NOVOCAINE) :

54 PROCAINE (NOVOCAINE) First synthetic injectable local anesthetic. Produce the greatest vasodilation of all currently used local anesthetics. Slower clinical onset (6-10 mins .) Used for Soft tissue anesthesia for 15- 30 mins . Systemic toxicity negligible because rapidly destroyed in plasma Max. recommended dose for peripheral nerve block 1000mg

LIDOCAINE:

LIDOCAINE The most popular contains epinephrine 1:100,000 and provides good anesthesia for healthy patients. Lidocaine with epinephrine 1:50,000 is used for hemostasis, but because of the rebound effect noted earlier, it should be used sparingly. Gold standard 1:200000 conc. is safest As well as potent 55

Lignocaine ( Xylocaine ) :

56 Lignocaine ( Xylocaine ) Most widely used Amide linked LA and most versatile ana . Has variety of applications like Local, nerve block, topical. When used locally action starts within 3 mts , more profound anesthesia, has longer duration of action and greater potency. Overdose causes muscle twitchings , convulsions, cardiac arrhythmias , fall in BP, coma, respiratory arrest. Most popular anti arrhythmic drug

Maximum Dose of Lignocaine:

Maximum Dose of Lignocaine Without Vasoconstrictor : 4.4 mg / kg of body wt = 300 mg in a 70 kg individual = 15 ml of solution With Vasoconstrictor : 7.2 mg / kg of body wt = 500 mg in a 70 kg individual = 25 ml of solution For children with VC 3.2 mg/kg Council for dental therapeutics- ADA 4.4mg/kg

MEPIVACAINE:

MEPIVACAINE 3% Mepivacaine without a vasoconstrictor is used as anesthetic for patients who cannot take a vasoconstrictor or for short procedures. It is appropriate for pedodontics and for use on geriatric patients. 2% Mepivacaine with vasoconstrictor provides pulpal anesthesia that is similar to lidocaine with epinephrine, but hemostasis is not as intense. Cardiac patients 58

PRILOCAINE:

PRILOCAINE The action of prilocaine plain varies with the area injected (longer with a nerve block). Prilocaine with vasoconstrictor gives good anesthetic effect and uses a 1:200,000 concentration of epinephrine . Secondary amine Orthotoulidine Liver+kidney+lung CO 2 methaglobinemia Biotransformation 59

ARTICAINE:

ARTICAINE Articaine is a newer anesthetic typically given in a 4% solution with 1:100,000 epinephrine. Practitioners reported rarely missing a inferior alveolar nerve block with Articaine . However, concern has arisen about its potential for tissue necrosis and persistent nerve parasthesia . Thiophene group Ester side chain Lipophilic,High penetrating Rare over dosage 60

BUPIVACAINE:

BUPIVACAINE Bupivacaine is used when pulpal anesthesia is desired for longer appointments and when postoperative pain is anticipated. Bupivacaine is not recommended for children or handicapped patients because of the increased risk of postoperative injury (chewing on a numb lip). CVS symptoms first Preemptive analgesia High pKa Sensoricaine 61

PowerPoint Presentation:

Available as 0.5% soln 1:2,00,000 ( vc ) Indicaton - pulpal anesthesia->90- min. Full mouth recontruction . Extensive oral and maxillofacial surgery, 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 .

POSTPROCEDURAL PAIN CONTROL:

POSTPROCEDURAL PAIN CONTROL Prescribe nonsteroidal antiinflammatory agents prior to the appointment Use an intermediate duration anesthetic for the procedure Inject bupivacaine just prior to the patient's dismissal Direct the patient to take oral analgesics for a certain number of days following the procedure. 63

ROPIVACAINE:

ROPIVACAINE It is prepared as an isomer rather than a racemic mixture Greater margin of safety between convulsive and lethal doses . A newer Bupivacaine congener, equally long acting but less cardio toxic. Sensory block is more compared to Motor. Ropivacaine is being used for relief of postoperative pain. I t can also be used for nerve blocks. It is available in USA not in India. 64

HYALURONIDASE:

HYALURONIDASE An enzyme that breaks down intracellular cement. Advocated as an additive to local anesthetics as it permit as injected solutions to spread and penetrate tissues. Available as Wydase in a lyophilized powder and a stabilized solution. Added to the cartridge just before administration by removing approximately 1/8th of solution. Allergic reactions have been demonstrated. 65

LOCAL ANAESTHESIA TECHNIQUE:

LOCAL ANAESTHESIA TECHNIQUE 66

TOPICAL:

67 TOPICAL The local anesthetic solution is applied on the mucous membrane or skin, through which it penetrates to anesthetize superficial nerve endings. e.g. - Ointments containing 5% lignocaine -Viscous solution containing lignocaine hydrochloride -Ethyl chloride sprays

INFILTRATION:

68 INFILTRATION Small terminal nerve endings in the area of dental treatment are flooded with local anesthetic. The treatment is done in the same place where anesthetic is deposited.

FIELD BLOCK:

69 FIELD BLOCK Local anesthetic solution is deposited near the larger terminal branches so the anesthetized area is well circumscribed. Incision or treatment is done at an area away from the site of injection of local anesthetic.

NERVE BLOCK:

70 NERVE BLOCK Local anesthetic solution is deposited close to the main nerve trunk, usually at a distance from the site of operative intervention

PowerPoint Presentation:

SUPRA PERIOSTEAL INJECTION 71

POSTERIOR SUPERIOR ALVEOLAR NERVE BLOCK:

POSTERIOR SUPERIOR ALVEOLAR NERVE BLOCK 72

PowerPoint Presentation:

74

MIDDLE SUPERIOR ALVEOLAR NERVE BLOCK:

75 MIDDLE SUPERIOR ALVEOLAR NERVE BLOCK

Middle Superior Alveolar Nerve Block:

Middle Superior Alveolar Nerve Block

INFRAORBITAL NERVE BLOCK:

INFRAORBITAL NERVE BLOCK 77

GREATER PALATINE NERVE BLOCK:

GREATER PALATINE NERVE BLOCK 81

NASOPALATINE NERVE BLOCK:

NASOPALATINE NERVE BLOCK 83

PowerPoint Presentation:

84

PALATAL APPROACH ANTERIOR SUPERIOR ALVEOLAR:

85 PALATAL APPROACH ANTERIOR SUPERIOR ALVEOLAR

MAXILLARY NERVE BLOCK:

87 MAXILLARY NERVE BLOCK

MAXILLARY NERVE BLOCK :

90 MAXILLARY NERVE BLOCK

INFERIOR ALVEOLAR NERVE BLOCK:

INFERIOR ALVEOLAR NERVE BLOCK 91

PowerPoint Presentation:

March 5, 2007 Faisal A. Quereshy, MD, DDS, FACS

PowerPoint Presentation:

March 5, 2007 Faisal A. Quereshy, MD, DDS, FACS

PowerPoint Presentation:

March 5, 2007 Faisal A. Quereshy, MD, DDS, FACS

PowerPoint Presentation:

March 5, 2007 Faisal A. Quereshy, MD, DDS, FACS

PowerPoint Presentation:

March 5, 2007 Faisal A. Quereshy, MD, DDS, FACS

PowerPoint Presentation:

BUCCINATOR / LONG BUCCAL NERVE BLOCK 97

PowerPoint Presentation:

March 5, 2007 Faisal A. Quereshy, MD, DDS, FACS

PowerPoint Presentation:

March 5, 2007 Faisal A. Quereshy, MD, DDS, FACS

PowerPoint Presentation:

MENTAL NERVE BLOCK 100

PowerPoint Presentation:

March 5, 2007 Faisal A. Quereshy, MD, DDS, FACS

PowerPoint Presentation:

GOW GATES TECHNIQUE– 1973 (MANDIBULAR N. BLOCK) 102

COMPLICATIONS OF LOCAL ANESTHETICS:

COMPLICATIONS OF LOCAL ANESTHETICS 105

DEFINITION:

DEFINITION “any deviation from the normally expected pattern during or after the securing of regional analgesia” 106

CLASSIFICATION:

107 CLASSIFICATION

LOCAL COMPLICATIONS:

LOCAL COMPLICATIONS Needle Breakage Prolonged anesthesia Facial nerve paralysis Trismus Soft- tissue injury Hematoma Pain on injection Burning on injection Infection Edema Sloughing of tissues Postanesthetic intra- oral lesions 108

SYSTEMIC COMPLICATIONS:

SYSTEMIC COMPLICATIONS Toxicity or Overdosage Allergy Idiosyncrasy Syncope Hyperventilation syndrome 109

EMLA = eutectic mixture of local anesthetics :

110 EMLA = eutectic mixture of local anesthetics Eutectic = two solid substances mixed together in equal quantities by weight form a eutectic mixture the melting point of the mixture is lower than the melting points of the individual components EMLA = lidocaine and prilocaine becomes an oily mixture

TAC: (LET) :

111 TAC: (LET) tetracaine 0.5%, adrenaline1 in 2000 and cocaine 10% topical anesthetic mixture found to be effective for nonmucosal skin lacerations to the face and scalp applied directly to the wound using a cotton-tipped applicator with firm pressure that is maintained for 20 to 40 minutes maximum dose for children-0.05ml/Kg toxicity due to cocaine

Thank You:

112 Thank You

authorStream Live Help