local ana in dent Flashcards
Define analgesia?
Absence of sensibility of pain, particularly the relief of pain without loss of consciousness
What do local anaesthetics do?
They eliminate sensations, especially pain, in one part of the body by the topical application or regional injection of a drug
What do local anaesthetics block?
They block entry of sodium ions into cells therefore blocks action potential
What are the 2 types of local anaesthetics?
- Amino esters– largely superseded (cocain, Procaine)
- Amino-amides: always have an i before the Caine bit: priolocain, lidocaine, mepivocaine, bupivacaine, articaine
What is the most common local anaesthetic we administer and what is the dosage we give?
Lidocaine 2% plain or with epinephrine 1:80,000
Describe Mepivacaine 3% plain 2% with epinephrine
It is plain and very short acting
Brand: scandonest
How are local anaesthetics metabolised excreted?
- Amino amides are metabolised by the liver| 2. Excreted via the kidneys
What advise do manufacturers say about the use of lidocaine?
manufacturers advise caution in patients with liver disease
Who should we avoid giving Felypressin?
Avoid in pregnancy
(Similar to oxytocin)
Who should we taken caution in giving Adrenalin / Epinephrine?
Care in ischaemic heart disease, hypertensives, unstable angina
What do Vasoconstrictors inc/ dec in local anaesthetics?
increase
-duration and depth of anaesthesia and reduce local blood flow
-increases length of action of local anaesthetic
Decrease
- lowers anaesthetic concentration in blood so decreases risk of toxicity
- decreases amount of bleeding at operation site
How can the operator reduce the chances of getting a needle stick injury?
Do not re-sheath or re-use| Use safety-plus system
How can patients have an allergy local cal anaesthetics?
Usually due to preservative| Was more common to ester-type (benzocaine, cocaine procaine).
Latex allergy may be triggered by rubber bung in cartridge. (Now more latex free but check packaging)
What are some symptoms of local anaesthetic allergy?
- Swelling2. Nausea malaise3. May lose consciousness4. Facial and laryngeal oedema
What are Psychogenic reactions a patient could have to LA?
Feeling faint
Fainting
Palpitations
Panic attack
What is a Vasovagal attack?
Fainting
What should you do if your patient faints?
- Lie them flat - head down
- Loosen tight clothing
- Call for help
- Give them a Glucose drink
If no improvement = - Check – airway, breathing, circulation
- Oxygen if necessary
- If not recovered in 2-3 minutes – assume not simple faint
Who should we take care with when administrating adrenaline?
Recent myocardial infarction or coronary artery bypass graft
Care in hypertension and heart problems (especially if unstable)
Care when using on patients tricyclic antidepressants, SSRIs, diuretics
What some adverse events that can occur when administering LA?
- Broken needle (Rare)
- Pain during or after
- Haematoma
- Trismus
- IV injection
- Blanching
- Facial paralysis
- Prolonged impaired sensation
- Soft tissue trauma
- Visual disturbances
How can we make LA less painful?
- explain, reassure, tailor treatment
- Use topical properly
- Room temperature cartridges
- Careful needle placement
- pressure w mirror handle, stretch tissues
- SLOW injection controlled delivery.
What symptoms can patients have is they get LA toxicity?
Effects on CNS and cardiac system:
Light headedness, dizziness, sedation, twitching
Can lead to Convulsions, loss of consciousness, respiratory depression and cardiovascular collapse
How much LA is usually found in 1 cartridge?
2.2ml
What is the maximum dose of lidocaine 2% we can give a health adult (70kg) ?
6.6mg/kg max 460mg (10.0 cartridges)
What is the maximum dose of 4% articaine we can give a health adult (70kg)?
7.0mg/kg max 490mg (5.0 cartridges)
What is the maximum dose of 3% Prilocaine we can give a health adult?
9.0mg/kg max 600 (19 cartilage)
What is the maximum dose of 2% mepivacaine plain| we can give a health adult?
4.4mg/kg max 300ml (14 cartridges)
What is the maximum dose of 3% Mepivacaine| we can give a health adult?
4.4mg/kg max 300mg (9 cartridges)
What should we beware of with the elderly?
Over the age of 65 liver function in the elderly reduces by 60% Therefore reduce safe dosages by 50%
Which causes of LA failure are operator dependant vs patient dependent?
Operator= choice of technique and solution, Poor technique
Patient= anatomical, pathological (infection), psychological (anxiety)
Define anaesthesia
Partial or complete loss of sensation, with or without loss of consciousness, a result of disease, injury, or administration of an anaesthetic agent, usually by injection or inhalation
Define LA
A temporary loss of sensation in one small area of the body caused by special drugs called anaesthetics. The patient is conscious, but without feeling in the area of the body treated with the anaesthetic.
Define Paraesthesia
Abnormal sensation (not specifically unpleasant), spontaneous or evoked
Define Dysesthesia
Unpleasant abnormal sensation, spontaneous or evoked
Define hypoaesthesia
Reduced perception of stimulus or decreased sensation
What are amino esters metabolised from?
pseudocholinesterase in the blood to form Amino esters metabolised by para-aminobenzoic acid
- can cause an allergic reaction
Describe Lidocaine 2% plain or with epinephrine 1:80,000 (i.e. 1:80k)
Most common, very effective
Brand: Lignospan special, Lignocaine, Xylocaine etc
Describe Prilocaine 4% plain or 3% with felypressin
Similar to lidocaine
Brand: Citanest, Citanest with octapressin
Articaine 4% with 1:100,000 or 1:200,00 epinephrine
Better diffusion, fast onset, hydrolysed quickly, not for IDBs
Brand: Septonest
Describe Bupivacaine 0.25%,0.5%,0.75% ampoules
Slow onset but long duration – 2 hours pulpal anaesthesia
Brand: Marcaine and Sensorcaine
Types of local anaesthetics
a) Prilocaine 3% and octapressin 0.03 IU per ml
b) Mepivicaine 3% plain
c) Articaine 3% and 1:10k epinephrine
d) Lidocaine 2% and 1:80k epinephrine
What must we avoid when giving LA?
• Intravascular injection (haematoma, systemic effects, ischaemia)
- always use aspirating syringe
Complications of LA
Psychogenic reactions – ask anxiety levels
LA toxicity
Allergy
Drug interactions
How could an allergic reaction be mimicked?
Psychogenic reaction- Patients often have a blush or erythema which mimics allergic reactions, hyperventilation, nausea, and vomiting
Equation to calculate max dose?
Safe max number of local anaesthetic cartridges =
Max safe dose of local anaesthetic (mg) x patient weight (kg)
________________________
Amount of local anaesthetic per cartridge
Mild allergy vs anaphylaxis
Mild= urticaria and rash, particularly of chest, hands and feet
Mild bronchospasm without evidence of severe shortness of breath
E.g Rhinitis, conjunctivitis
Anaphylaxis= wheezing
Tachycardia (heart rate >110 per minute) and inc respiratory rate
Symptoms of anaphylaxis
Abdominal pain, vomiting, diarrhoea, impending doom
Flushing, but pallor may also occur,
Mild allergy
Intra-oral topical anaesthetics
• Xylonor® Gel 5% lidocaine analgesic gel
• 20% Benzocaine Topical Anaesthetic bubble gum flavour
• Lidocaine 4% ointment or gel
• 10% Lidocaine intraoral spray
• Oraqix ® (Lidocaine and Prilocaine periodontal gel) 2.5% / 2.5%
Extra-oral (skin) topical anaesthetic
• EMLA - 2.5% / 2.5% Lidocaine and Prilocaine
• AMETOP – 4% tetracaine
How to apply topical anaesthetic
1)Dry the area of needle placement with cotton wool roll
2) Place a pea sized amount of topical anaesthetic onto a cotton wool roll or pledget and tweezers and place onto area of needle placement and wait for a 2 to 3 minutes
3) Perform you local anaesthetic injection
How should you communicate to a patient while delivering LA?
DONT:
needle or injection, negative phrases e.g. ‘this might hurt’
DO:
Explain using ‘neutral’, age-appropriate phrasing
Explain what to expect post-op e.g. duration of anaesthesia and care not to cause inadvertent soft tissue trauma
