Local & systemic Complications of Local Anesthesia

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  • 1. LOCAL ANAESTHESIA Lec .#7 Success and Complications of LA Dr. Adel I. Abdelhady BDS, MSC, (EG) Phd (EG,USA) Oral and Maxillofacial Surgery Dept. College of Dentistry, King Faisal University, KSA. .
  • 2. Mechanism of Action     Ionized anesthetic binds to sodium channel. Sodium entry is blocked into these channels. Sodium channel blockade prevents propagation of action potentials. Lack of propagation blocks sensation, as signal is not transmitted to brain.  
  • 3. The outline     Reducing discomfort during injection of LA Testing the success of LA Management of failure anaesthesia Complications of LA Local complications  Systemic complications   LA and pregnancy
  • 4. Factors influencing injection discomfort?  The needle: Sharp & small gauge  The syringe: Aspirating to avoid local and systemic effects  The cartridge: Smooth bung to avoid judder and allow steady injection  The solution: Temperature: >15 – 37< is not detected by the patient. pH: (LA with VC is acidic (3.2)…..Painful, LA without VC is less acidic (6.8)……….Painless Rate of injection: faster injection is painful.
  • 5. Technique of reducing injection discomfort?    Use the correct technique and equipments Apply topical anaesthesia Stretch the mucosa with finger  Distract the patient at the moment of the mucosa is pierced  Position the needle supraperiosteally Direct the bevel toward the bone Slow injection decrease pain and limit the LA to the intended site slow removal of the needle   
  • 6. Testing the success of LA  Testing for successful LA should be determined before commencing any procedure by either:  Subjective testing: by asking the patient to describe areas of altered sensation, usually +ve with nerve block and anterior maxillary and mandibular injections.  Objective testing: using probe, pulp testing or percussion
  • 7. Testing the success of LA     When you probe soft tissue, always consider supplementary nerve supply I A is usually +ve The onset time for I A is 2-3 mn & for NB is 3-5 mn. Pulpal LA has a longer onset time compared to soft tissue anaesthesia
  • 8. Causes of failure anaesthesia • • Wrong technique Anatomical variations: • • • • • • • • Bifid or double nerve supply Nerve anastomosis: central line Secondary supply by a soft tissue nerve: LN, LBN & GPN Inadequate dose Sepsis acidity Injection in BV Anxiety reduced patient pain threshold Patient immaturity
  • 9. Management of failed local anaesthesia • • • • • Check anatomical landmarks Repeat injection Consider alternate or additional technique Consider whether anxiety may be contributory Settle pain and inflammation and try again about a week later
  • 10.  If local anaesthetic is deposited too far medially away from the inferior alveolar nerve, it is blocked from travelling laterally by the sphenomandibular ligament and its associated fascia. This ligament runs from the sphenoid process to the lingula, and attached to it is a fascia that fans out in a sagittal direction. Local anaesthetic cannot cross this barrier, and it is therefore crucial to inject lateral to the ligament. Otherwise, the patient will experience incomplete anaesthesia or maybe even no anaesthesia at all.
  • 11.  Another anatomical factor to consider is the vasculature. If the local anaesthetic is deposited into a vessel, no anaesthesia is obtained. It is recommended to use a wider-lumen (lower-gauge) needle to increase the likelihood of success in obtaining a positive aspiration. For example, a 25-gauge needle offers a much more reliable indicator of positive aspiration than does a 30gauge needle, which offers a very poor indicator of positive aspiration.
  • 12.  A fourth factor, also anatomical, is the thickness of the nerve. The inferior alveolar nerve, at the level of the conventional mandibular nerve block, is thinner than the core mandibular nerve, which is approximated in the Gow-Gates block. This thicker nerve requires a longer onset time for complete infiltration; the conventional mandibular nerve block takes 3 to 4 minutes to complete anaesthesia, compared to the 10 to 12 minutes for the Gow-Gates block.
  • 13.  A fifth factor to consider is the actual volume of the local anaesthetic. Some patients require more than one cartridge of local anaesthetic to anaesthetize the mandible. Accessory innervation (see below under "Skeletal and neuroanatomic variations"), thicker nerves and larger patients may necessitate more anaesthetic. For such patients, a practitioner may decide to give two cartridges of local anaesthesia in slightly different locations - for example, one in the location of the conventional block, and one in the area of the GowGates block. The extra dose maximizes the volume and saturates the pterygomandibular space with anaesthetic.
  • 14.  Another crucial skeletal anatomical variant is the width of the internal oblique ridge. It is on this ridge that the practitioner's finger must rest for all mandibular block procedures, including the conventional, the Vazirani-Akinosi and the Gow-Gates. If the patient has an exceedingly wide internal oblique ridge and the practitioner's finger is not resting on this ridge of bone, it is very difficult to negotiate the needle past this bony ridge to approach the inferior alveolar nerve. This nerve is located on the medial aspect of the ramus behind the large ridge. Palpating a wide inferior alveolar ridge is also cause to rotate the syringe more posteriorly, toward the contralateral molars
  • 15.  A final skeletal anatomical factor is the position of the mandibular foramen. The location of this foramen can vary both in its anterior - posterior position and its inferior - superior position. Blocks given more superiorly, for example, the Gow-Gates block, may in part be more successful due to the increased chance of being superior to this foramen. Therefore, the local anaesthetic is not being deposited inferior to where the nerve enters the mandible (which would result in incomplete anaesthesia).
  • 16. Local anaesthetic or vasoconstrictor degradation All local anaesthetic cartridges have an expiry date on their label. This date tells the practitioner the product's shelf life from the time of manufacturing to the time when a certain number of the anaesthetic or vasoconstrictor molecules have degraded to a degree that the product may be less effective. Local anaesthetic molecules are relatively stable and degrade very slowly. As a result, the shelf life of a local anaesthetic depends mostly on the stability of the vasoconstrictor. For this reason, sodium metabisulphite is used as a preservative or stabilizer for the vasoconstrictor molecule. A number of factors can lead to the premature breakdown of an anaesthetic and the vasoconstrictor within a cartridge, including extreme temperatures, excessive light and oxygen exposure. To maximize the shelf life of the contents inside the cartridge, the local anaesthetic molecule should be stored at room temperature away from sunlight and room light. Dental offices are unlikely to experience temperature extremes, but consideration should be given to how the local anaesthetic was delivered to the office. Local anaesthetics can easily freeze or overheat if left in a delivery truck during seasonal extremes. These temperature variations can lead to the premature degradation of the molecules in the cartridge
  • 17. Manarola,
  • 18. Management of failure maxillary LA
  • 19. Management of failure mandibular LA
  • 20. Contraindications of LA A. General Contraindications: Un-cooperative patient  Treatment factors:  Time consideration  Access problem  Acute infection  Allergy: ester > amide  Medical conditions  Poor blood supply 
  • 21. Contraindications of LA B. Contraindications to specific techniques:    Bleeding diatheses: avoid N B Susceptibility to endocarditis and incomplete root formation : avoid intraligamentary Trismus: precludes IANB, GPN, NPN, . use Akinosi tech  Epilepsy, cardiac pacemakers, and cerebrovascular disease: avoid Electronic LA
  • 22. Complications of LA  Causes: • • • • • Doctor factor (wrong technique) Vasoconstrictor LA Needle Patient factor
  • 23. LOCAL ANAESTHESIA Complications of LA Dr. Adel I. Abdelhady BDS, MSC, (EG) Phd (EG,USA) Oral and Maxillofacial Surgery Dept. College of Dentistry, King Faisal University, KSA. .
  • 24. Complications of LA I. Localised II. Systemic I. Localised complications:    Pain: during and postinjection Failure A Equipment failure:   Broken needle Cartridge failure.  Neurological problems:      Prolonged altered sensation Unilateral facial nerve paralysis Visual disturbances Aural disturbances Extensive paralysis: reversed flow to the brain
  • 25. Tasks  Methemoglobinemia  Fainting/syncope
  • 26. Complications of LA  Causes: • • • • • Doctor factor (wrong technique) Vasoconstrictor LA Needle Patient factor
  • 27. Factors influencing injection discomfort?  The needle: Sharp & small gauge  The syringe: Aspirating to avoid local and systemic effects  The cartridge: Smooth bung to avoid judder and allow steady injection  The solution: Temperature: >15 – 37< is not detected by the patient. pH: (LA with VC is acidic (3.2)…..Painful, LA without VC is less acidic (6.8)……….Painless Rate of injection: faster injection is painful.
  • 28. Technique of reducing injection discomfort?    Use the correct technique and equipments Apply topical anaesthesia Stretch the mucosa with finger  Distract the patient at the moment of the mucosa is pierced  Position the needle supraperiosteally Direct the bevel toward the bone Slow injection decrease pain and limit the LA to the intended site slow removal of the needle   
  • 29. Causes of failure anaesthesia • • Wrong technique Anatomical variations: • • • • • • • • Bifid or double nerve supply Nerve anastomosis: central line Secondary supply by a soft tissue nerve: LN, LBN & GPN Inadequate dose Sepsis acidity Injection in BV Anxiety reduced patient pain threshold Patient immaturity
  • 30. Management of failed local anaesthesia • • • • • Check anatomical landmarks Repeat injection Consider alternate or additional technique Consider whether anxiety may be contributory Settle pain and inflammation and try again about a week later
  • 31.   Another anatomical factor to consider is the vasculature. If the local anaesthetic is deposited into a vessel, no anaesthesia is obtained. It is recommended to use a wider-lumen (lower-gauge) needle to increase the likelihood of success in obtaining a positive aspiration. For example, a 25-gauge needle offers a much more reliable indicator of positive aspiration than does a 30-gauge needle, which offers a very poor indicator of positive aspiration.
  • 32. Management of failure maxillary LA
  • 33. Management of failure mandibular LA
  • 34. Needle Breakage Causes  Unexpected movement  Small needle size  Bent needles  Defective needles
  • 35. Needle Breakage Prevention  Use large needles  Use long needles for deep injection,>18mm  Never insert to hub  Redirect only when adequately withdrawn
  • 36. Rush Hour, Venice
  • 37. Needle Breakage Management  Remain calm  Don't explore  Have the patient keep opening wide  If the needle is out remove it  Refer to an Oral Surgeon
  • 38. Localised complications:  Vascular problems:        Intravascular injection Haematoma Sloughing of oral mucosa Self-inflicted trauma Trismus: due to bl. & LA Infection Interference with wound healing: adrenaline & dry socket
  • 39. Pain on Injection Causes  Dull needles  Rapid deposit of solution  Needles with barbs  Careless technique
  • 40. Pain on Injection Prevention  Careful technique  Sharp needles  Topical anesthetic  Slow injections  Room temperature solutions
  • 41. Burning on Injection Causes  pH of solution  Rapid injection  Contamination  Warmed solutions
  • 42. Burning on injection   A burning sensation on injection may occur for two reasons. First, local anaesthetics with a vasoconstrictor are acidic because of the preservative required for the vasoconstrictor. This acidity can cause the anaesthetic to burn when it is injected into tissues. As the cartridge ages and approaches the expiry date, the vasoconstrictor begins to break down, resulting in even a lower pH and therefore even more burning on injection.
  • 43. Burning on injection  Second, if cartridges are immersed in sterilizing solution and the solution seeps into the cartridge, the sterilizing solution can cause a burning sensation upon injection. The likelihood of a burning sensation can be minimized by using fresh anaesthetics with little or no vasoconstrictor and by injecting slowly.
  • 44. Persistent Anesthesia or Paresthesia Causes     Trauma to nerve Neurolytic agents (alcohol, phenol) Intraneural injection Hematoma
  • 45. Persistent Anesthesia or Paresthesia Prevention  Careful injection technique  Unavoidable at times
  • 46. Persistent Anesthesia or Paresthesia Management  Patient counseling and reassurance  Documentation  Follow-up
  • 47. Trismus A motor disturbance of the trigeminal nerve precipitating or resulting in spasm of the muscles of mastication Causes  Trauma to muscles or blood vessels  Contaminated anesthetic solutions  Hemorrhage  Infection  Excessive anesthetic volume
  • 48.   Injection of local anaesthetic directly into muscle may cause a mild myotoxic response, which can lead to necrosis. The symptoms of trismus, often associated with pain, arise anywhere from 1 to 6 days following an injection. The duration of symptoms and their severity are both variable. With management as described below, improvement should be noted within 2 to 3 days. If there is no improvement within this time, the dentist should consider other possible causes (e.g., infection) and treat accordingly.
  • 49. Trismus Prevention  Sharp needles  Proper care and handling of cartridges  Aseptic technique and clean injection site  Atraumatic insertion  Minimal injections and volume
  • 50. Trismus Management  Examination  Conservative therapy  passive ROM therapy  analgesics  heat  muscle relaxants
  • 51.     Prevention :Follow basic principles of atraumatic injection technique. Management: Apply hot moist towels to the site for approximately 20 minutes every hour. Use analgesics as required. Advise the patient to gradually open and close the mouth as a means of physiotherapy.
  • 52. Hematoma The effusion of blood into extravascular spaces  This localized mass of extravasated blood may be seen after the inadvertent piercing of a blood vessel during the injection or when withdrawing the needle. Blood vessels are often pierced during intraoral injections, but only when there is sufficient blood extravasation is there a hematoma.
  • 53. Hematoma  A second relatively common localized complication is a hematoma. The vessels most commonly associated with a hematoma are the pterygoid plexus of veins, the posterior superior alveolar vessels, the inferior alveolar vessels and the mental vessels. The patient will notice swelling and discolouration (bruising) lasting 7 to 14 days.
  • 54. Prevention  Follow basic principles of atraumatic injection technique. Use a short needle for the posterior superior alveolar nerve block.  Management  If hematoma is visible immediately following the injection, apply direct pressure, if possible. Once bleeding has stopped, discharge patient with instructions to        Apply ice intermittently to the site for the first 6 hours. Do not apply heat for at least 6 hours. Use analgesics as required. Expect discolouration. If difficulty in opening occurs, treat as with trismus, described above
  • 55. Prolonged anaesthesia or paraesthesia   Prolonged anaesthesia or paraesthesia in the tongue or lip is a known risk of surgical procedures such as extractions but may also occur following non-surgical dentistry if local anaesthetic has been administered. These reactions are most often found after block techniques and much less commonly after infiltrations. The precise causes of paraesthesia are not certain, but they may include needle trauma or the injection of alcohol or sterilizing solutions. Articaine and prilocaine are more likely than other anaesthetics to be associated with paraesthesia and have most commonly affected the lingual nerve.
  • 56.   Unfortunately, there is no method certain to prevent paraesthesia or prolonged anaesthesia. The inferior alveolar nerve block requires the practitioner to advance the needle near the inferior alveolar and lingual nerves. The needle should come near these nerves without touching them. An accidental touch may be perceived as an "electric shock" sensation by the patient but will not necessarily result in paraesthesia. Direct contact with these nerves is not an indication of improper technique; it is simply a risk of intraoral injection.
  • 57.  The vast majority of paraesthesias are transient, resolving within 2 months, but they can become permanent. If the patient reports continuing paraesthesia, the dentist should note the signs and symptoms and maintain contact with the patient. A change in the character of the symptoms is encouraging in that it may indicate healing of the nerve and resolution of symptoms; with time, the patient may regain normal sensation.
  • 58. Prevention    If patient feels "electric shock", move the needle away from the site before injecting. Do not store cartridges of local anaesthetic in disinfecting solutions. Minimize the use of articaine and prilocaine for block technique.  Management  Advise the patient that the paraesthesia or anaesthesia is usually temporary, although, rarely, it can remain indefinitely. Note the signs and symptoms and follow up within 1 month. If symptoms persist for more than 2 months, refer the patient to an oral and maxillofacial surgeon who has experience in this field.  
  • 59. Hematoma Prevention  Care with needle placement  Minimize injections  Don't probe with needle  Modify technique o short needles o penetration depth
  • 60. Infection Causes  Needle contamination  Improper handling of armamentarium  Infection at injection site  Improper handling of tissue
  • 61. Infection Prevention  Disposable needles  Proper care of equipment  Aseptic technique
  • 62. Infection Management  Usual sign is trismus  Trismus persists (1-3 day resolution )  Antibiotics, if suspicious
  • 63. Edema Management  Address cause  Treat accordingly  hemorrhage  allergy  infection
  • 64. Sloughing of Tissue Causes  Topical anesthetic  Prolonged ischemia Management  Observation  Documentation
  • 65. Lip Chewing Management  Analgesics  Antibiotics  Saline rinses  Lip lubricants
  • 66. Facial Nerve Paralysis Cause       Anesthesia of peripheral Facial nerve branches Temporal Zygomatic Buccal Mandibular Cervical
  • 67. Facial Nerve Paralysis Prevention  Bone contact when injecting  Avoid over penetration  Avoid arbitrary injection
  • 68. Facial Nerve Paralysis Management  Reassure patient  Cornea care  Documentation  Consider deferring dental care 
  • 69. Dolomite Mountains,
  • 70. Complications of LA Systemic adverse effects complications:      Toxicity (due to LA &  Methemoglobinemia: VC) (Haemoglobin contains iron in  General NS toxicity Ferric not Ferrous state  Cardiovascular leading to poor oxygenation Toxicity and cyanosis (Treated by IV Drug interactions 1% methylene blue 1.5 Allergic effects mg/kg. o-toluidine (oxidise Iron) is a metabolic product Fainting/syncope of Prilocaine. Idiosyncrasy Articaine, Benzocaine?
  • 71. LA Toxicity LA Toxicity Manifestations and management Manifestations and management Prevention
  • 72. LA Toxicity   Local anaesthetic toxicity is due to systemic absorption of an excessive amount of the drug. Because local anaesthetics block conduction in many tissues in addition to the peripheral nerve, toxicity could result if sufficient amounts of the anaesthetic reach these other tissues, such as the heart or brain. High blood levels of the drug may be secondary to repeated injections or could be a result of a single intravascular administration. This risk is one reason why aspiration prior to every injection is so important.
  • 73. Calculations of Doses  Percent solutions represent grams per 100 mL Move the decimal place to the right and this value = mg/mL (i.e. lidocaine 2% = 20 mg/mL)Most cartridges = 1.8 mL. Therefore, one cartridge of 2% lidocaine contains 1.8 mL x 20 mg/mL = 36 mg.
  • 74. Manifestations and management of LA toxicity a Manifestations •Mild Management toxicity: • Stop administration of all local Talkativeness, anxiety, slurred speech, confusion anaesthetics • Monitor vital signs • Observe in office for 1 hr Moderate toxicity: • Stop administration of all local Stuttering speech, anaesthetics nystagmus, tremors, • Place in supine position headache, dizziness, blurred vision, drowsiness • Monitor vital signs • Observe in office for 1 hr.
  • 75. Manifestations and management of LA toxicity b Manifestations Sever toxicity: seizure, cardiac dysrhythmia or arrest. Management Place in supine position • If seizure, protect from nearby objects and suction oral cavity if vomiting occurs • Have someone summon medical assistance • Monitor vital signs • Administer oxygen • Start IV • Administer diazepam 5-10 mg slowly or midazolam 2-5 mg slowly • Institute BLS if necessary • Transport to emergency care facility •
  • 76. Suggested maximum dosage of local anaesthetics Drug Common brand Concentration Percentage Maximum number of 1.8 ml cartridges Lidocaine Xylocaine 2% 10 Lidocaine + Epin. Xylocaine with epinephrine 2% lidocaine 1:100000 epinephrine 10 Mepivacaine Carbocaine 3% 6 Mepivacaine + norad. Carbocaine with neo-cobfrin 2% mepivacaine 1:20000 levonordefrin 8 Prilocaine Citanest 4% 6 Bupivacain + Adren. Marcaine with epinephrine 0.5% bupivacaine 1: 200 000 10 Etidocaine Duranest with 1.5% etidocaine 15
  • 77. General Principles No drug exerts a single action  No drug is non-toxic  Potential toxicity is user dependent 
  • 78. Adverse Drug Reactions Direct extensions of usual effects  Side effects  Overdose  Local toxic effects
  • 79. Adverse Drug Reactions Altered recipient  Disease process  Emotional disturbances  Genetic aberrations  Idiosyncrasy
  • 80. Adverse Drug Reactions Allergic reaction  Immediate - anaphylaxis  Delayed - contact dermatitis
  • 81. Overdose Dose related  Systemic distribution  Extension of pharmalogic effects  Selective CNS or CVS depression 
  • 82. Allergic Reactions Not dose related  May be systemic or localized  Unrelated to pharmacological effects  Exaggerated immune system response 
  • 83. Idiosyncrasy Reaction Unexplained by any known mechanism of the drug’s action  Neither overdose nor allergic reaction  Unpredictable; treat symptoms 
  • 84. Predisposition - Overdose Patient factors  Age  Weight  Sex  Medications
  • 85. Predisposition - Overdose Drug factors  Rate of injection  Vascularity of site  Vasoconstrictors  Concentration  Dose  Route of administration
  • 86. Cause of Overdose Levels Total dose is too large  Absorption is too rapid  Intravascular injection  Bio-transformed too slowly  Eliminated too slowly 
  • 87. Biotransformation Esters are hydrolyzed in the plasma and liver by pseudo-cholinesterase into PABA  Amides are bio-transformed by microsomal enzymes in liver 
  • 88. Elimination Both esters and amides are eliminated through kidney, some in unchanged form eg. (lidocaine - 10%)  Prilocaine is eliminated by lungs 
  • 89. Rapid Absorption Vasoconstrictors should be used unless specifically contraindicated
  • 90. Intravascular Injection Toxicity Occurrence varies with type of injection: Nerve Block % positive aspirate  Inf. alveolar 11.7  Mental/Incisive 5.7  Post. sup. alv. 3.1  Ant. sup. alv./ Buccal <1
  • 91. Mild to Moderate Symptoms:  Restless  Nervous disturbances  Numbness Visual disturbances Auditory Metallic taste
  • 92. Mild to Moderate Signs (cont.):  Elevated BP Sweating  Elevated heart rate Nausea/vomiting  Elevated resp. rate Disorientation  Failure to follow commands / reason  Lack of response to painful stimuli
  • 93. Mild to Moderate Symptoms (cont.):  Light-headed and dizzy  Drowsy and disoriented  Losing consciousness  Sensation of twitching (before actual  twitching is observed)
  • 94. Moderate to High Generalized tonic-clonic seizure activity  followed by  Generalized CNS depression  Depressed BP, heart rate  Depressed respiratory rate 
  • 95. Pathophysiology Local anesthetics cross blood-brain barrier, producing CNS depression as level rises eg. LIDOCAINE  Blood Level Action Produced  < .5 ug/ml - no adverse CNS effects  0.5-4 ug/ml - anticonvulsant  4.5-7.5 ug/ml - agitation, irritability  > 7.5 ug/ml - tonic-clonic seizures
  • 96. Pathophysiology Local anesthetics exert a lesser effect on the cardiovascular system eg. LIDOCAINE Blood Level Action Produced 1.8-5 ug/ml - treat PVCs, tachycardia 5-10 ug/ml - cardiac depression >10 ug/ml - severe depression, bradycardia, vasodilatation, arrest
  • 97. Mild Reaction -slow onset Reassure patient  Administer O2  Monitor vital signs  Consider IV anticonvulsant  Allow recovery or get medical help prn  Get medical consultation, esp. if possibility of metabolic or renal dysfunction 
  • 98. Severe Reaction - slow onset Stop all treatment  Establish airway, give O2 (BLS)  Administer anticonvulsant  Summon emergency medical help  Consider vasopressors  Get medical consultation, esp. if possibility of metabolic or renal dysfunction 
  • 99. Psychogenic reactions    Anxiety-induced reactions are by far the most common adverse event associated with local anaesthetics in dentistry. Fainting (syncope) is the most common manifestation of fear of the injection. Other common reactions include hyperventilation, nausea, vomiting and changes in heart rate or blood pressure. Because psychogenic reactions can mimic allergic reactions, such as urticaria (rash), edema (swelling) and bronchospasm (wheezing), they are often misdiagnosed.
  • 100. Allergy    Reports of allergic reactions to local anaesthetics are somewhat common, but investigation finds most of these reactions to be of psychogenic origin. A confirmed allergy to an amide is rare; the ester procaine is somewhat more allergenic. An allergy to one ester rules out using another ester, as the allergenic component is the breakdown product para-aminobenzoic acid (PABA), and all esters are metabolized to this product. Conversely, an allergy to one amide does not rule out using another amide. Epinephrine has not been shown to have any allergenic potential.
  • 101.   Allergies to the other contents in the cartridge are possible. Methylparabens are preservatives used for multi-dose vials. They were universally used until the early 1980s, and certain products continued to include them as late as 1994. Today, they are no longer included in dental cartridges, as these are all single-use items. In the past, methylparabens were often found to be the source of allergy; thus, a patient's history of allergy "to dental anaesthetic" may originate from a time when methylparabens were in use.
  • 102. Allergy - signs/symptoms Respiratory:  Laryngeal edema  Bronchospasm, wheezing  Use of accessory muscles  distress  dyspnea  anxiety  cyanosis or flushing  tachycardia Dermatologic:  Urticaria - wheals, pruritis  Angioedema  Minor rash
  • 103. Adverse Drug Reactions Allergic reaction  Immediate - anaphylaxis  Delayed - contact dermatitis
  • 104. Allergic Reactions Not dose related  May be systemic or localized  Unrelated to pharmacological effects  Exaggerated immune system response 
  • 105. Allergens in Local Esters - usually to the Para-amino-benzoicacid product Na bisulfite or metabisulfite - found in anesthetics as perservative for vasoconstrictors Methylparaben - no longer used as perservative in dental cartridges
  • 106. Management of Allergy Pts.  If the patient gives a history of allergy to local anesthetics - Assume that an allergy exists Elective procedures  Postpone until work-up is completed 
  • 107. Anaphylaxis Typical progression *  Skin reactions  Smooth muscle spasms (GI, GU, respiratory)  Respiratory distress  Cardiovascular collapse  *may occur rapidly, with considerable overlap
  • 108. Management of Reactions        Delayed skin reaction Benadryl - 50 mg stat & Q6H X 3-4 days Immediate skin reaction Epinephrine 0.3 mg IM or SC Benadryl - 50 mg IM Observation, medical consultation Benadryl - 50 mg Q6H X 3-4 days
  • 109. Management of Reactions Bronchial constriction  Semi-erect position, O2 - 6 L/min  Inhaler or Epinephrine 0.3 mg IM or SC  Benadryl - 50 mg IM  Observation, medical consultation  Benadryl - 50 mg Q6H X 3-4 days 
  • 110. Management of Reactions Laryngeal edema  Place supine, O2 - 6 L/min  Epinephrine 0.3 mg IM or SC  Maintain airway  Benadryl - 50 mg IV or IM  Hydrocortisone - 100 mg IV or IM  Perform Cricothyrotomy
  • 111. Management of Reactions Anaphylaxis  Place supine, on flat surface  ABCs of CPR, call for medical help  Epinephrine 0.3 mg IV or IM (Q 5 mins)  O2 - 6 L/min, monitor vital signs  After clinical improvement,  Benadryl and Hydrocortisone
  • 112. Differential Diagnosis Pyschogenic reaction (Syncope)  Overdose reaction  Hypoglycemia  Stroke (CVA)  Acute adrenal insufficiency  Cardiac arrest 
  • 113. LA and pregnancy  LA pass passively through the placenta, yet, rate and degree are dependent on the LA protein binding.  LA of choice is Lignocaine with Adrenaline Others cause cardiovascular collapse as: Bupivacaine and Oxytocin effect as felypressin (VC).
  • 114. Leaning Tower of Pisa
  • 115. Prevention and management of medical emergencies   Prevention Preparation     Personal continuing education in emergency recognition and management Auxiliary staff education in emergency recognition and management Establishment and periodic testing of readily access medical assistance. Equipping office with supplies necessary for emergency care.
  • 116. Medical emergencies commonly provoked by anxiety in dental unit • • • • • • • • • • Fainting/ syncope Angina pectoris Myocardial infarction Asthmatic bronchospasm Adrenal insufficiency (acute) Severe hypertension Thyroid storm Insulin shock Hyperventilation Epilepsy
  • 117. References 1. 2. SF Malamed: Pain and anxiety control for the conscious dental patient, 1997. Meechan, et al., Hand book of local anaesthesia, 1998.
  • 118. Church of Selva Di Cadore, Colle Santa Lucia
  • 119. Child -Toxic dose of LA
  • 120.        Examples of calculations of maximum local anaesthetic doses for a 20-kg (44-lb) child (assuming that each cartridge holds 1.8 mL) Articaine 5 mg/kg x 20 kg = 100 mg 4% articaine = 40 mg/mL 100 mg / (40 mg/mL) = 2.5 mL Each cartridge = 1.8 mL, therefore maximum dose = 2.5 mL / 1.8 mL Therefore maximum dose = 1.4 cartridges
  • 121.  Lidocaine  7 mg/kg x 20 kg = 140 mg 2% lidocaine = 20 mg/mL 140 mg / (20 mg/mL) = 7.0 mL Each cartridge = 1.8 mL, therefore maximum dose = 7.0 mL / 1.8 mL Therefore maximum dose = 3.9 cartridges    
  • 122. Mepivacaine      6.6 mg/kg x 20 kg = 132 mg 3% mepivacaine = 30 mg/mL 132 mg / (30 mg/mL) = 4.4 mL Each cartridge = 1.8 mL, therefore maximum dose = 4.4 mL / 1.8 mL Therefore maximum dose = 2.4 cartridges Prilocaine      8 mg/kg x 20 kg = 160 mg 4% prilocaine = 40 mg/mL 160 mg / (40 mg/mL) = 4 mL Each cartridge = 1.8 mL, therefore maximum dose = 4 mL / 1.8 mL Therefore maximum dose = 2.2 cartridges