LA Flashcards
difference between an infiltration and a block anaesthesia?
infiltration
- around terminal branches
- for soft tissue where pulpal anaesthesia able through thin bone
- thus used for the mandible anterior & maxillary teeth
block
- at nerve trunk
- stops sensation distal to block
- for soft tissue where bone too thick for infiltration
- used in posterior mandible
pros and cons of infiltration anaesthesia?
pros
- technically easy
- atraumatic
- high success rate
cons
- pulpal anaesthesia limited to 1 or 2 teeth
- infection and dense bone limits effect
- sore bellow periosteum
what are the components of anaesthetic
type
- ester or amide
vasoconstrictor
- none, adrenaline or felypressin
preservatives
- bisulphite
- propylparaben
injections used to anaesthetise maxillary pulp, buccal and palatal gingiva?
buccal infiltrations for pulp and buccal gingiva
palatal infiltration for palatal gingiva
how to anaesthetise mandible pulps of teeth where bone is too thick for infiltration? (molars, premolars and canine)
lower molars (and second premolar) - IDB
lower premolars (and canine) - mental (incisive) nerve block
canine (and incisors) - buccal and labial infiltration
what does IDB/IAN mean in LA?
inferior dental block otherwise know as inferior alveolar nerve block
injection given for mandibular buccal gingiva for 1. lower molars and second pre molar, 2. first premolar and canine and 3. lower incisors and canine
- long buccal
2.
description of how to anaesthetise an entire side of the mandible (pulps, lingual gingiva, anterior AND posterior gingiva)
- IDB given to anaesthetise the pulps of the entire half arch and the anterior buccal gingiva (1-5)
- when retracting the needle from IDB release part of the cartridge to anaesthetise the lingual nerve (lingual gingiva and tongue)
- second injection is a long buccal block and for the long buccal nerve when there is an extraction of a posterior necessary as this still innervates the posterior buccal gingiva
how to anaesthetise mandible lingual and buccal gingiva of the mandible (123 & 34 & 45678)
123 buccal - buccal/labial infiltration
34 buccal - infiltration/long buccal block/mental nerve block
45678 buccal - long buccal infiltration
ALL lingual gingiva - IDB drawback while releasing to anaesthetise lingual nerve OR lingual infiltration
what are the benefits of a higher gauge needle for LA
thinner needle so less deflection of tissue, greater accuracy, reduced risk of breakage, easier aspiration
how many ml is there in a LA and what syringe type do we use
2.2ml and safety needles
osce station: assemble LA safety needle
- check expiry date and note batch number of anaesthetic cartridge
- unpack everything minding rubber bung and put decontamination label in patient notes
- assemble everything
- when done can resheath (1 click) or lock (2clicks)
LA injection technique
- stretch mucosa and puncture quick with distraction
- aspirate at injection target area
- inject slowly (30sec min) NOT continuous, but drip method
- resheath and massage tissue
- wait 2 mins then check if worked
where inject LA for mental nerve block
between apices of premolars
process for a palatal injection
- short needle injected 5-10mm palatal to centre of crown
- while applying pressure behind injection site
- 45 degree angle injection with bevel facing soft tissue
- when hit bone deposit 0.2-0.4ml slowly
process for giving an IDB in LA? (hand positions and needle positions)
non working hand fingers - posterior border of mandible
non working hand thumb - coronoid notch
needle
- 35mm needle used
- LA valve over opposite premolars
- needle inserted next to the deepest part of the pterygomandibular raphe at about 6-10 mm above occlusal plane
- marker for needle entry is in between the coronoid notch and the deepest raphe (but closer to the raphe) and angled from opposite premolars so the needle reaches the area around the sigmod notch at the condyle where the alveolar nerve is
process - needle should hit bone with 1cm of needle still visible then retract 1 cm and aspirate (if before 1cm left then move mesial as too early, if dont hit bone then the vise versa)
what are the markers for helping you give an IDB in the right position in LA?
- coronoid notch
- coronoid process
- sigmoid notch
- condyle
- posterior border of the mandible
- pterygomandibular raphe
describe lidocaine/lingocaine/xylocaine
- amide type LA
- lidocaine HCL 2%
- for infiltration, blocks, etc
- either plain or 1:80,000 adrenaline
- half life up to 2 hrs
- contraindications
- heart block without pacemaker
- allergy to LA or Corn
- hypotension
- impaired liver function
describe articane
- amide type LA
- articane 4%
- infiltrations or blocks but as stronger and very good at diffusing to pulp through alveolar bone generally just infiltrations
- half life of 20 mins
- contraindications
- sickle cell patients and other haemoglobinpathies
describe citanest/prilocaine
- amide LA
- prilocaine HCL 3%
- infiltration and blocks
- either plain or with felypressin octapressin
describe mepivicaine
- 3% plain
- typically used in patients with cardiac disease as has less of a need for vasocontrictor than lidocaine as will naturally last longer
what to do if patient has a panic attack (i.e. over LA)
lie them flat down, loosen neck clothing and improve room ventilation
what are the contraindications for LA when a patient is on beta blockers?
BP increases as vasodilatory receptors blocked
what are the contraindications for LA when a patient is on beta blockers and for using adrenaline?
Beta blockers - BP increases as vasodilatory receptors blocked
adrenaline (epinephrine) - when taking diuretics (further reduces potassium levels)
how to calculate the max safe does of each of the 4 anaesthetics?
lidocaine
- 5mg/kg
- 2% so 44mg/cartridge
- avg person (70kg) = 7 cartridges
articaine
- 7mg/kg
- 4% so 88mg/cartridge
- avg = 5
prilocaine
- 8mg/kg
- 3% so 66mg/cartridge
- avg = 8
mepivicaine
- 3mg/kg
- 3% so 66mg/cartridge
- avg = 6
how to calculate the max safe does of each of the 4 anaesthetics?
lidocaine
- 5mg/kg
- 2% so 44mg/cartridge
- avg person (70kg) = 7 cartridges
- children max 4.4mg/kg
articaine
- 7mg/kg
- 4% so 88mg/cartridge
- avg = 5
prilocaine
- 8mg/kg
- 3% so 66mg/cartridge
- avg = 8
- children max 6mg/kg
mepivicaine
- 3mg/kg
- 3% so 66mg/cartridge
- avg = 6
what is trismus
- appears hours after IDB
- restricts eye lid function
- caused by damage to medial pterygoid (too low or forceful
issues that can occur after LA injection?
- trismus
- intravascular injection (skin blanching and visual disturbance - needs specialist)
- facial palsy
- infection
- broken needle
tissue damage (if needle blunts after injections - needs changed)
what is facial palsy caused by and what are the characteristics of it?
- LA into parotid gland (too posterior)
- appears in minutes
- check only lower face (if whole face = stroke)
- cover eye with patch
- gradual improvement after 2 weeks
two ways to give a painless palatal anaesthetic?
- chasing anaesthesia (buccal infiltration -> interdental papilla injection and advance until palate blanches -> inject palate)
- new tech
how use intraligamental LA
- used if tooth not anaesthetised after other LA
- 3 locations buccally then lingually
- bevel facing ligaments and a lot of force as will splash out
- can use peripress/peripress pen syringe
what is an intraosseus LA injection
- stabident perforatior on slow speed into bone then needle to inject
what are topical jet injectors
pressure forces LA into tissue
- expensive, scary, taste and damages mucosa
- good for bleeding diatheses
- anaesthetises 1cm deep tissue
what are the two alternatives to an IDB when patient cant open their mouth
- akinosi technique
- does mandibular, long buccal and lingual
- pull cheek open, needle parallel to occlusal plane above gingiva crevice, in a few cm - Gow gates
- US technique
- open mouth technique
- patient lying down, aim for neck of condylar process then draw back
what is the wand in paeds for LA?
- pedal activated machine that deposits LA at constant rate and is made to look less intimidating and single use
- for intraligamentary LA
how deep does topical benzocaine 20% flavoured anaesthetise?
2-3mm
- note: dry area before use and applied for 2 minutes
reasons for using oral topical LA
• Pre-injection • Rubber dam clamp • Placing matrix band • Suture removal • Exfoliating primary teeth • Subgingival scaling Incision of abscess
notable differences in LA anatomy of child and adult
- children smaller and higher mandibular foramen
- more anterior mental foramen
where do we inject for a mental block in children
between 1st and 2nd primary molars
what to be careful of in LA when working on an incisor
may have midline cross over so make sure dully anaesthetised
contraindications to LA in children
- In bleeding disorders, avoid IDB
- Allergy
- Acute infection
- Care in liver disease: amide dose reduction
Dos and donts for behaviour management of children in LA
donts
- bribe, shout, coax, bully, threaten, allow child to have their own way etc
dos
- empathetic, make nice environment, ask how doing etc
techniques
- tell show do
distraction
rolemodelling
How does a local anaesthetic work chemically?
…
How much of a cartridge is given while doing an IDB
3/4 to 2/3 at IDB site then retract a few millimetres and deposit the rest for the capsule
