Complications Of Local Anaesthetic Flashcards
Describe what makes up lidocaine solution
- Amide type LA
- Lidocaine HCL 2%
- Vasoconstrictor
- plain (none)
- or 1:80000 adrenaline
Describe the components that make up prilocaine solution
- Amide LA
- Prilocaine HCL 3%
- Vasoconstrictor
- plain
- or felypressin (octapressin): 1.2 micro grams
Describe the components of articaine?
- Amide type LA
- 4% with ADR
- 1:100000
- 1:200000
- 1:400000
List the different systemic complications that can occur with LA
- Psychogenic
- Interaction with other drugs
- Cross infection
- Allergy
- Collapse
- Toxicity
List psychogenic/stress complications that can occur with LA (7)
- Fainting
- Palpitations
- Cold sweat
- Restlessness
- Excitation
- Trembling
- Weakness
What is the main cause of psychogenic/stress complications?
Lack of oxygenated blood to the brain
What are clinical features of psychogenic/stress complications?
- Lightheaded ness
- Pallor
- Beads of sweat (lip:nose:temple)
- Bradycardia (slow pulse)
- Nausea
- Pupil dilation
How do we manage a patient suffering from psychogenic/ stress complications (i.e. faint)
- Lay flat and raise legs
- Loosen neck clothing
- Improve room ventilation
- Sweet drink (low blood sugar)
What are normally causes of perceived allergy to local anaesthetic?
- Historically due to latex bung
- Most are due to preservatives/antioxidant
- methylparaben/sodium bisulphite
What complications associated with toxicity can occur with LA?
- Convulsions
- Loss of conciousness
- Respiratory depression
- Circulatory collapse
Why should use of oxtapressin be avoided in pregnant women?
It can induce labour
What techniques can be used to reduce potential toxic effects?
- Aspiration
2. Slow rate of introduction
What are the maximum doses in mg/kg for:
- mepivicaine 3% plain
- lignocaine 2% adr 1:80,000
- articaine 4% adr 1:100,000
- prilocaine 3% octapressin
Max dose (mg/kg): • 3 • 5 • 7 • 8
What effect does adrenaline have on the heart?
- Rate increases
- Force increases
- Output increases
- Excitability increases
(Sympathetic nervous system)
Beta-1
What effect does adrenaline have on blood vessels?
- Coronary dilation
- Skin contraction
- Muscle dilation
(Sympathetic nervous system)
Alpha and beta 2
What effect does adrenaline have on blood pressure and the lungs?
Blood pressure: 1. Systolic increases 2. Diastolic decreases - overall there is little effect (Sympathetic nervous system) Alpha and beta 2
Lungs:
- bronchial muscle relaxation
Beta 2
What are contra-indications of adrenaline?
- Cardio vascular disease
- avoid adrenaline
- or use less than 3 2.2ml cartridges - Hyperthyroidism (thyroid crisis)
- Phaeochromocytoma (hypertension)
- Drug interactions
- mono amine oxidase inhibitors
- tricyclic antidepressants
- beta blockers
- non potassium sparing diuretics
- halothane (G.A. Agent)
- cocaine
What are local complications that can occur when using LA? (12)
- Failure to achieve anaesthesia
- bad technique, wrong location, infection - Prolonged anaesthesia
- damaged the nerve - Pain during or after injection
- Trismus
- Hematoma
- Intra-vascular injection
- Blanching
- Facial paralysis
- Broken needle
- Infection
- Soft tissue damage
- Contamination
What causes prolonged anaesthesia?
- Direct trauma from needle
- Multiple passes with the same needle
- Chemical trauma from direct injection
- Different depending on LA used
What teeth are anaesthetised by an infraorbital block?
- Central incisors, lateral incisors and canines
Describe the presentation of trismus, it’s cause and management of the condition
Presentation:
- within a few hours of inferior dental block, there may be severely restricted opening of the mouth
- may last for weeks or months
Cause:
- most likely due to damage of the medial pterygoid
- could be due to injection being too low or too forceful/rapid
Management:
- reassurance (after diagnosis)
- muscle relaxant
- anti inflammatory
What are differences between local anaesthetic induced facial palsy and palsy following a stroke
Stroke patients are still able to move some muscles in the affected side of the face
LA induced palsy presents with complete paralysis of all the muscles on one side of the face
Describe the following aspects of facial palsy:
- Presentation
- How to confirm
- What is the cause
- How to diagnose
- How to manage
- Presentation: usually complete Unilateral motor nerve paralysis within minutes of inf dental blocks
- Confirm: temporal branch affected (I.e lower motor neurone distribution
- Cause: local into parotid gland - injection too far posteriorly
- Diagnosis: test branches of CN VII (facial nerve)
- Management: reassurance, cover effected eye with pad until blink reflex returns
What are signs of an intra arterial injection of LA?
- Skin blanching
- Visual disturbance
- Aural disturbances
Intra arterial is very rare
What type of LA injections are most commonly associated with accidental IV injection?
Block injections - most likely inferior Dental block
What are the most common symptoms of an IV LA injection?
Palpitations most common •also: - anxiousness - restlessness - headache - sweating - pallor
(All due to adrenaline)
