Systemic Complications of Local Anesthesia PDF

Systemic Complications of local anesthesia 1. Syncope/Fainting:  Definition:  Sudden and transient loss of consciousness as a result of cerebral ischemia  Most common medical emergency in dental clinic  Self-limiting (rapid onset, short duration, spontaneous complete recovery...

Systemic Complications of local anesthesia 1. Syncope/Fainting:  Definition:  Sudden and transient loss of consciousness as a result of cerebral ischemia  Most common medical emergency in dental clinic  Self-limiting (rapid onset, short duration, spontaneous complete recovery)  Predisposing factors:  Fear and anxiety.  Pain (sudden & unexpected pain).  Sight of blood or instruments.  Crowded environment.  Pathophysiology of syncope:  Stress → Release catecholamines → ↑blood flow to peripheral skeletal muscles (prepare the individual for increased muscular activity “fight-or- flight” response) → however, the planned-for muscular activity does not occur (e.g., sitting still in the dental chair) → significant pooling of blood in these muscles → ↓ venous return →↓ BP and cerebral blood flow.  Clinical Manifestations  Pale skin tone, Nausea, Cold hands and feet, Hypotension, Visual disturbances, muscular twitching of the hands, legs, Loss of consciousness.  Management:  Discontinue dental treatment  P—Position patient supine with feet elevated slightly  C → A → B— Assess circulation (palpate carotid pulse for up to 10 seconds) and start chest compressions if no palpable pulse, Open airway (head tilt– chin lift), Assess breathing and provide ventilation as needed.  remove dentures, loosen tight clothing.  Verbally communicate with the patient for assurance and to access level of consciousness.  If it last for more than 15 min check for another cause of fainting. 1  Prevention Placing the patient into a supine position before receiving a local anesthetic injection is frequently all that is needed to prevent vasodepressor syncope. 2. Allergic reaction to LA:  Two forms of allergy are of particular consequence in the practice of dentistry:  Type I: Anaphylaxis (immediate hypersensitivity) → Seconds to minutes→ Clinical examples: Generalized anaphylaxis, Angioedema, Urticaria (in the skin), Bronchospasm  Type IV (delayed hypersensitivity) →48 hours→ Allergic contact dermatitis.  Predisposing factors:  Sodium [meta]bisulfite (V.C Antioxidant).  Ester L.A agents  Clinical Manifestations:  In general, the more rapid signs and symptoms of allergy occur after exposure, the more intense is the ultimate reaction and the more aggressive its management. 2  Prevention:  Medical history Questionnaire: Allergic to any medications? Have you ever had a reaction to local anesthesia? What type? If yes, describe what happened and the treatment given.  If doubt remains concerning the nature of the allergy problem after completion of the dialogue history, → referral of the patient to a Physicians → skin test.  Allergy testing in the dental o ice should not be considered for the following reasons. Skin testing, although potentially valuable, is not foolproof. Localized histamine release (false-positive reactions) may result from the trauma of needle insertion. The skin test would be negative or a positive response which would be delayed for many hours. Skin testing is not without risk. The possibility (though remote) that even the minute quantity of local anesthetic injected (0.1 mL) could precipitate an immediate and acute systemic anaphylaxis. Drugs, equipment, and personnel needed for the management of anaphylaxis must always be available when allergy testing is undertaken.  Allergy testing:  Intra-cutaneous testing 0.1 ml of test sol. is administered subcutaneously in patient forearm. The local anesthetics to be tested must be free of all additives (preservatives and vasoconstrictor) ----Plain. If no response to the skin testing occurs, an intraoral injection may be given to confirm the result with the selected local anesthetic (Challenge test).  Challenge test 0.9 mL of the previously local anesthetic solutions that produced no reaction is injected intraorally via supraperiosteal infiltration atraumatically (but without topical anesthesia) above a maxillary right or left premolar or anterior tooth. 3  The patient should be observed for 1-1.5 hours after the last injection to determine that no delayed reaction will occur.  If dental patient confirm allergy to L.A prevention of allergy is done according to its nature:  If allergy is limited to ester-typeAmide type is used.  If allergy is limited to amide typeOther amide type is used as cross allergenicity between amides doesn’t exist.  If doubts persistDental treatment safely done via G.A, Histamine blockers, Nitrous oxide and oxygen.  Management:  If there is no airway obstruction Oral Antihistamines should be administered The patient should be referred to an allergist.  If there are airway obstruction / Symptoms remain severe  P-Position, if unconscious, the patient is placed supine  Basic life support: C → A → B— Assess circulation (palpate carotid pulse for up to 10 seconds) and start chest compressions if no palpable pulse, Open airway (head tilt–chin lift), Assess breathing and provide ventilation as needed.  IM epinephrine 1:1000 in a dose of 0.3 mL every 5 to 20 minutes as needed, to a total of three doses. (0.15 mg if  30 kg)  Note that 1:1,000 epinephrine concentrations are not intended for intravenous administration.  The administration of a histamine-blocker (diphenhydramine 50 mg [>30 kg]) and corticosteroid 100 mg (their administration are not recommended before epinephrine during the acute phase of the reaction because they are too slow in onset) 4 3. Drug Overdose Reactions  Signs and symptoms of overdose appear when the local anesthetic blood level in the brain or heart rises above a critical level.  Causes of high blood levels of local anesthetics 1. Drug is slowly eliminated from the body through the kidneys→ to prevent → pretreatment physical evaluation of patient 2. Too large a total dose → to prevent →Administration of minimal doses 3. Rapid absorption of drug into circulation→ to prevent → Use of vasoconstrictor 4. Intravascular injection → to prevent →Aspiration; slow injection  Clinical manifestations:  Prevention:  Medical History Questionnaire.  Calculation of Maximum Recommend Dose (MRD)  Patient weight X Toxic limit of drug =Toxic limit in mg Toxic limit in mg /Total mg in cartridge = Maximum cartridges allowed. 5  Management  Most local anesthetic overdoses are self-limiting; the blood level of the local anesthetic decreases over time as the reaction progresses.  Terminate dental treatment and assure patient.  Protect the patient from falling from the chair or lift them onto the floor. 6  Turn the patient onto their side to reduce the possibility of them aspirating secretions and recent dental work.  Call the emergency services if the seizure lasts longer than five minutes or the patient experiences repeated seizures.  Basic life support C → A → B  Definitive treatment: Monitor vital signs, Administer Anticonvulsants. 7 8 9 10 11