BDS2 - LA symposium > LA complications > Flashcards

LA complications Flashcards

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1
Q

what are the 3 types of LA most commonly used

A
  • lignocaine = most used
  • can use pressin as well
  • or artisane which is general in 4%
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2
Q

what is lidocaine

A
  • amide type LA
  • lidocaine HCl 2% = or can get 3% one without vasoconstrictor
  • vasoconstrictor = adrenaline, 1:80,000
  • uses = infiltrations/blocks and others
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3
Q

what is citanest

A
  • chemical name is prilocaine HCl 3%
  • comes plain or octapressin vasoconstrictor in it = 1.2mcg
  • amide LA
  • uses = infiltrations, block and others
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4
Q

what is articaine

A
  • amide type LA
  • 4% with adrenaline = 1:100,000 or 1:200,000 (tend to use this one) or 1:400,000
  • uses = infiltrations and blocks
  • metabolised in the liver plasma and excreted in kidney = lidocaine also like this
  • more rapid onset that lidocaine and is more potent
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5
Q

how long is lignocaine infiltration pulpal anaesthesia

A
  • 60 mins
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6
Q

what is lignocaine block pulpal anaesthesia

A
  • 90 mins
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7
Q

what is articaine infiltration pulpal anaesthesia

A
  • up to 120 mins
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8
Q

what is articiane block pulpal anaesthesia

A
  • 75 mins
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9
Q

what is prilocaine infiltration pulpal anaesthesia

A
  • 30-45 mins
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10
Q

what is prilocaine block pulpal anaesthesia

A
  • 60 mins
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11
Q

what are systemic complications of LA

A
  • psychogenic/stress
  • interaction with other drugs
  • cross infection
  • allergy
  • collapse
  • toxicity
  • pregnancy
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12
Q

what is the most common type of systemic complication with LA

A
  • psychogenic

- especially common with anxious patients

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13
Q

what can happen with psychogenic complications

A
  • can have = faint, palpitations, cold sweat, restlessness, excitation, trembling, weakness
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14
Q

what is the natural response to fainting

A
  • to remain lying down so oxygen stays at head, don’t want to get up
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15
Q

what do palpitation feel like

A
  • heart is bounding out of chest
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16
Q

how can patient get weakness from LA

A
  • from standing up too quickly
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17
Q

what is the cause of fainting

A
  • lack of oxygenated blood to the brain
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18
Q

what are the clinical features of fainting

A
  • light-headedness
  • pallor
  • beads of sweat at lips, nose and temple
  • bradycardia = slow pulse
  • nausea
  • pupil dilation
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19
Q

what is the management of fainting

A
  • lay flat and raise legs
  • loosen neck clothing
  • improve room ventilation
  • give them a sweet drink = could have fainted due to not having anything to eat or drink that day
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20
Q

what are some drugs that can interact with LA

A
  • MAOI = most exogenous adrenaline is metabolised via Catechol which is a methyl-transferase system
  • try-cyclic = theoretical risk of hypertension due to inhibitor of uptake of adrenaline at sympathetic nerve terminals( only use 1:80,000)
  • beta blockers = pressor increase as vasodilatory beta 2 adrenergic receptors blocked
  • non potassium sparing diuretics = relatively low K may b further enhanced by adrenalines K lowering action
  • cocaine = increased adrenergic activity
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21
Q

what do patients often mistake for being allergic to LA

A
  • feeling faint or bounding heart but that is just due to adrenaline
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22
Q

what wa the main cause of allergy of LA historically

A
  • the latex bung but hat is no longer made of let
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23
Q

what are most LA allergies caused by

A
  • preservatives/antioxidants

- methlypraben/sodium bisulphate

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24
Q

what can patient get if they are allergic

A
  • skin rashes of respiratory effects of even full blown anaphylaxis but this is rare
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25
what must you do if patient is truly allergic
- they need to be sent for patch testing - allergens are placed on discs and left on for 24, 72 or 96 hours to see if allergic reaction has taken place or not - if truly allergic then patients not treated in general practice
26
how can toxicity be caused by LA
- given too much
27
what are the effects of toxicity of LA
- convulsions - loss of consciousness - respiratory depression - circulatory collaps
28
what can toxicity be mistaken for
- fainting | - both cause circulatory depression and loss of consciousness so need to know the difference between them
29
what must you avoid giving pregnant women
- LA with oxtapressin in it as this can induce labour - oxtapressin is the vasoconstrictor in citanest and it is the same type of drug as oxytocin which is used to induce labour
30
how is maximum safe dose of LA calculated
- the average is calculated in a 70kg adult who is fit and healthy
31
how should maximum safe doses be calculated
- on an individual basis
32
how can you reduce toxic effects of LA
- by using aspirating technique | - don't inject directly into blood vessel
33
how do you decrease chance of overload
- by injecting slowly
34
what must you remember about the dose of LA
- it is only talking into account the LA, not the vasoconstrictor which some say is just as dangerous
35
what is the maximum safe dose for lignocaine 2% and cartridges
- max dose = 5mg/kg - 44mg in a cartridge - for 70kg adults = 7 cartridges
36
what is the maximum safe dose for articaine 4% and cartridges
- max dose = 7mg/kg - 88mg in a cartridge - for 70kg adult = 5 cartridges
37
what is the maximum safe dose for prilocaine 3%
- max dose = 8mg/kg - 66mg in a cartridge - for 70kg adult = 8 cartridges
38
what can adrenaline have an effect on
- heart - blood vessels - blood pressure - lungs
39
how can adrenaline affect the heart
- rate increased by beta 1 - force increased by beta 1 - output increased by beta 1 - excitability increased by beta 1
40
how can adrenaline affect the blood vessels
- coronary dilation - skin contraction by alpha - muscle dilation by beta 2
41
how can adrenaline affect blood pressure
- systolic increases - diastolic decreases - overall = little effect
42
how can adrenaline effect lungs
- bronchial muscle relaxation by beta 2
43
what are the dangers of adrenaline
- cardio-vascular disease = use <3x2.2ml cartridges - hyperthyroidism = thyroid crisis - pheochromocytoma = hypertension - drug interactions
44
what drugs can adrenaline interact with
- monoamine oxidase inhibitors - tricycling antidepressant - beta blocker s - non-potassium sparing diuretics - halothane = G.A agent - cocaine
45
what are local complications of LA
- failure to achieve anaesthesia - prolonged anaesthesia - pain during of after injection - trismus - haematoma - intra-vascular injection - blanching - facial paresis - broken needle - infection soft tissue damage - contamination
46
how can you fail to anaesthetise
- might be due to a variety of things = technique, swelling or infection in area so reduces efficacy of LA
47
what are the causes of prolonged anaesthesia
- direct trauma to nerve from needle - multiple passes with same needle = once you contact bone the tip of the needle come blunt so if you go back through tissue then it causes more damage, so need to get new needle - chemical trauma for direct injection
48
how can you tell if you have cause chemical trauma and what do you do
- can happen with IAN block - can tell because patient will jump = its like an electric shock - if this happens then withdraw then aspirate then give LA = if you don't aspirate then LA could go straight into nerve and cause other problems
49
what has caused pain during or after injection
- given too fast or if patient has muscular spasms | - e.g. in IAN
50
what is trismus
- patient unable to open their mouth due to muscle spasms - will resolve but can be scary for patient = need to reassure - can occur within a few hours = could last for weeks or months
51
what is the cause of trisumus
- injection is too low of too forceful or too rapid
52
what is the management of trismus
- reassurance - muscle relaxant = like diazepam to help muscle open - anti-inflammatories = stronger than ibuprofen - provide with some device to open jaw
53
what is haematoma
- youve hit a blood vessel and this can then cause trismus
54
what happens if you do a intra-vascular injection
- have to aspirate - can cause systemic issues - intra-arterial is very rare but can cause = skin blanching, visual disturbance and hearing disturbances - all will only last a short while but if persist then need referral - intravenous usually occur from block injections
55
how can you avoid intra-vascular injections
- by careful technique, aspirating system | - slow drug introduction in safe quantity = if get blood when aspirate then come out
56
what are the features of intro-vasulcar injection
- most frequently noted will be adrenaline effect = symptoms most likely is palpitations - also get anxiousness, restlessness, headache, sweating and pallor
57
what causes blanching
- intra-vascular injection
58
what is the difference between a local anaesthetic induced palsy and a stroke palsy
- stroke = tend to have had a bleed in the brain that causes muscle fibres of facial muscle not to work properly - if stroke on right side of brain then affects left side of face due to cross-innervating of fibres - stroke patients from palsy tend to still be able to move their forehead muscles - with LA palsy, all branches of facial nerve are affected and so patient can't move that while side of their face
59
what is an easy way to remember the difference between stroke palsy and LA palsy
- upper spares upper - upper motor neurone disease spares the upper branches of facial nerve - lower motor neurone disease affects whole half face
60
what is the presentation of LA palsy
- usually complete unilateral motor nerve paralysis within minutes of giving it - happens very quickly
61
how can you confirm that it is an LA palsy
- if patient can't wrinkle forehead then temporal branch of facial nerve has been affected
62
what is the cause of LA palsy
- LA has gone into parotid gland = injection is too far posterior - instead of touching bone, you have deposited LA in parotid gland - affected all branches of the facial nerve as it sits in the parotid gland
63
how do you manage the LA palsy
- reassurance - cover eye with a pad until blink reflex returns as eye could dry out - will get better in a couple hours once LA wears off
64
what happens if needle breaks
- patients needs to get area surgical explored to remove needle
65
what are the different types of LA block
- mental block of mental nerve - infraorbital - inferior alveolar nerve block - posterior superior alveolar nerve block
66
where is mental block given
sit in apices between 4 and 5 usually - if give good LA here it will anaesthetise skin over chin ad lip region as well as buccal mucosa from lower 4 to lower central and also the teeth here
67
where is infraorbital nerve
- sits at mid-papillary line just under extra-orbital rim an under this there is a foramen where the maxillary branch of the trigeminal nerve terminates, and it supplies sensation to lateral part of nose and skin and also the feeling to the central and lateral canine teeth - good for supplying more than one tooth in upper anterior area if LA given here
68
where is the posterior superior alveolar nerve block given
- it hits a block further back than the IAN block so can catch maxillary nerve further back and provides anaesthesia of all teeth on right hand side and skin of nose and lip area - difficult to do however
69
is there an increased risk of injury if use stronger LA
- probably - a paper showed more chance if injury with 4% LA - need to use caution if using 4% articaine LA
70
what are the incidences of risk with each type of LA
- lidocaine = 1 in a million - prilocaine = 1 in 600,000 - articaine = 1 in 440,000
71
what is most used at Glasgow
- lidocaine 2% with adrenaline for blocks
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