LA Flashcards
WHAT DO YOU PALPATE WHEN DOING AN IDB
coronoid notch
ascending ramus
pterygomandibular raphe
HOW DO YOU ASPIRATE
push forward a tiny bit and let go
look for blood
WHY ASPIRATE
to avoid injecting LA into the BV
HOW LONG SHOULD YOU BE INJECTING IN AN IDB
30-45seconds
WHEN DOING AN IDB HOW MUCH OF THE CARTRIDGE SHOULD U DEPOSIT BEFORE RETRACTING
2/3 - last bit for lingual nerve - continuously injecting as retracting out the tissue
HOW LONG TIL FULLY ANAESTHETISED AFTER IDB
3-4 mins
HOW DO YOU DISPOSE OF THE NEEDLE
re-sheath - 1 click
secure - 2 clicks
remove the LA cartridge - blue bin
needle in orange bin
WHICH LA CANT BE USED IN PREGNANT WOMEN
prilocaine as it contains felypressin
WHAT DOES FELYPRESSIN DO TO PREGNANT WOMEN
induces labour
WHICH VASOCONSTRICTOR HAS CONSIDERATIONS WITH HEART PATIENTS AND WHY
adreneline as it can cause heart palpitations when acting on alpha receptors
IN WHAT SCENARIO WOULD YOU USE ARTICAINE OVER LIDOCAINE
when you are trying to anaesthetise a bigger area with less injections / avoiding a palatal as articaine is 4% compared to 2% lidocaine ( same vasoC)
WHY DOES FELYPRESSIN LA’S WASH OUT FASTER THAN ADRENLINE ONES
as adrenaline provides haemostatic control which means it doesn’t wash out as fast
WHAT CAN HAPPEN IF WE INJECT TOO STRAIGHT ON FOR AN IDB
hit parotid gland which contains facial nerve causing bells palsy
WHAT TO DO IF YOU GIVE THEM BELLS PALSY
don’t panic, pretty normal
send home with eyepatch so eye doesn’t dry up as cant close on own
HOW TO TELL THE DIFFERENCE BETWEEN A STROKE AND LA INDUCED PALSY
stroke = can still use forehead muscles
bells palsy = cant move anywhere on that side, all droopy
WHEN GIVING LA WHICH HAND IS USED FOR WHICH ACTION
dominant hand to inject
non dom to retract tissues
WHICH LA INJECTION WOULD HAVE THE PATIENT LYING THE FLATTEST
palatal
then buccal
then IDB
WHAT ARE THE MAIN LA PREPARATIONS
lidocaine 2% HCl = + 1:80000 adreneline
prilocaine 3% HCl + felypressin (0.03U/ml)
articaine 4% + 1:200000 adreneline
WHAT IS THE RESTING MEMBRANE POTENTIAL
-70mV
WHAT IS DEPOLARISATION OF AXON CAUSED BY
influx of Na+ ions through ion gated channels into the cell
WHAT IS REPOLARISATION CAUSED BY
efflux of K+ ions through ion gated channels
WHY IS THERE A REFRACTORY PERIOD IN ACTION POTENTIALS
as the Na+ ion channels are inactivated from previous AP
so AP cant propagate
IS THE ICF NEGATIVE OR POSITIVE
negative - more K+
WHAT FEATURES OF AN AXON MAKE IT HAVE QUICKER CONDUCTION SPEED
larger and myelinated
WHAT IS SALTATORY CONDUCTION
the AP passes along myelinated axons by skipping from one node of Ranvier to the next - fast
HOW DOES LA WORK PHYSIOLOGICALLY
blocks the Na+ voltage gated ion channels so depolarisation is blocked
WHICH AXON TYPES FUNCTION IS MOST LIKELY TO STILL BE FELT AFTER LA AND WHY
Aa as its the biggest axon with the most Na channels to be blocked so the least susceptible
COMPOSITION OF LA
the LA
- aromatic region
- ester or amide bond
- hydrophilic region
reducing agent
preservatives / fungicides
vasoC
WHICH COMPONENT OF LA IS HYDROPHOBIC AND WHY DO WE NEED IT
the aromatic region
to pass through the membrane
WHY DO WE NEED A HYDROPHILIC REGION OF LA
to be soluble in water to be in an injection solution
WHY DO WE NEED A HYDROPHILIC REGION OF LA
to be soluble in water to be in an injection solution
WHEN IS LA IN ACTIVE FORM
when it is ionised (has H)
after inside the cell
WHEN IS LA IN INACTIVE FORM
when its unionised (H removed)
when passing membrane
HOW IS LA WRITTEN CHEMICALLY
B.HCl
WHAT IS THE REDUCING AGENT IN LA
sodium metabisulphide
WHICH LA ARE ESTER BOND
benzocaine
cocaine
procaine
WHICH LA ARE ESTER BOND
benzocaine
cocaine
WHICH LA ARE AMIDE BOND
lidocaine
prilocaine
articaine
WHY DO LA SOLUTIONS NEED A VASOCONSTRICTOR
as LA work as vasodilators which washes the LA out faster
TYPES OF VASOCONSTRICTOR
adrenline
felypressin
WHAT IS THE EFFECT WHEN ADRENLINE WORKS ON ALPHA ADRENORECEPTORS
vasoconstriction
WHAT IS THE EFFECT WHEN ADRENELINE WORKS ON B1 ADRENORECEPTORS
heart palpitations when given systemically
WHICH RECEPTORS DOES FELYPRESSIN WORK ON
ADH - anti diuretic hormone - receptors
HOW IS LA INACTIVATED FROM TISSUES
washed out by blood supply
esterases
liver amidases
HOW LONG DOES LIDOCAINE LAST
infiltration = 60 min
block = 90 min
soft tissues = 3-5hours
HOW LONG DOES PRILOCINE LAST
infiltration = 30-45 min
block = 60 min
soft tissues = 3-6 hours
HOW LONG DOES ARTICIANE LAST
infiltration = 120 min
block = 75 min
soft tissues = 3-5 hours
WHERE IS LA DEPOSITED IN INFILTRATIONS VS BLOCKS
around terminal branches of nerve
VS
beside nerve trunk
WHY CANT WE DO INFILTRATIONS ON POSTERIOR TEETH IN MANDIBLE
bone is too thick for infiltration to anaesthetise pulp
WHAT AREAS NEED ANAESTHETISED FOR EXTRACTION
everything = pulp, ging, surrounding soft tissues
WHAT AREAS NEED ANAESTISED FOR EXTRACTION
everything = pulp, ging, surrounding soft tissues
WHAT AREAS NEED ANAESTHETISED FOR A RESORATION
pulp and gingiva (clamp/dam)
WHAT AREAS NEED ANAESTHETISED FOR SCALING
gingiva and sometimes pulp
WHAT IS THE GAUGE
diameter of needle lumen
lower number = larger lumen
SMALLER NEEDLE LUMEN ADVANTAGES
less deflection / reduced breakage risk / easier aspiration
SHORT NEEDLE GAUGE AND LENGTH
gauge 30
length 20-25mm
LONG NEEDLE GAUGE AND LENGTH
gauge 27
length 30-35mm
LA CLINICAL PROCESS
brief patient, consent check batch no, expiry date and correct LA make syringe adjust seat and light prep needle for use injection make needle safe again and dispose
HOW TO APPLY TOPICAL
dry mucosa
pea size on cotton wool
hold for 1-2mins
2 TYPES OF TOPICAL GELS
benzogel 20%
xylonor gingiva gel (lidocaine 2%)
WHAT IS A SUPRAPERIOSTEAL INJECTION
infiltration
WHERE TO INJECT FOR A BUCCAL INFILTRATION
3/4mm above apex
slightly distal
HOW LONG DO YOU WAIT BEFORE TESTING IF A BUCCAL INFILTRATION WORKED
2 mins
LIMITATIONS OF A BUCCAL INFILTRATION
pathology limits such as abscess
dense bone limits
ADVANTAGES OF A BUCCAL INFILTRATION
atraumatic
easy
high success rate
WHY IS THERE MORE RESISTANCE IN A PALTAL INFILTRATION THAN BUCCAL
the mucosa is more tightly bound to the bone
WHERE IS THE INJECTION SITE OF A PALATAL INFILTRATION
5-10mm palatal of centre of crown
or
midway between ging margin and deepest vault of palate
delete
d
WHY USE MIRROR BEHIND INJECTION SITE IN PALATAL INFILTRATION
to compress the mucosa and distract from the discomfort
HOW TO DO A PALTAL INFILTRATION
mirror needle at 45 degrees to injection site bevel towards tissue few mm in - if contact bone then withdraw 0.2-0.4ml anaesthetic (1/8 cartridge) look for blanched tissue
WHAT LANDMARKS SHOULD YOU LOOK FOR WHEN DOING AN IDB
coronoid notch of mandible (thumb)
ascending ramus of mandible (fingers)
pterygomandibular raphe
HOW TO CONFIRM ANAESTHESIA IN IDB FROM PATIENT
tongue and lower lip extending to midline on that side should feel different
but still feel pressure
IDB PROCESS
locate site inject hit bone and withdraw 1cm of needle always visible aspirate inject for 30-45seconds do lingual nerve of way out
WHY DO WE NEED TO DO A LONG BUCCAL INJECTION
as the buccal gingiva of the mandible is not innervated by the inferior alveolar nerve but the buccal nerve
INFILTRATION FINGER RESTS
maxilla = pinky of non injecting hand on chin mandible = thumb of non injecting hand to balance barrel on
IDB FINGER RESTS
pinky of injecting hand around ramus of opposite side to injection
or
balance barrel on thumb of non injecting hand
LIDOCAINE CONTRAINDICATIONS
heart block and no pacemaker
allergy to LA or corn
hypotension
impaired liver function
INDICATIONS FOR ARTICAINE
better than lidocaine for mandible infiltrations
when trying to minimise the amount of injections as its stronger than lidocaine
ARTICIANE CONTRAINDICATIONS`
stronger preparation increases risk of non-surgical parathesisa
sickle cell disease/ other haemoglobinopathies
SYSTEMIC COMPLICATIONS OF LA
stress cross infection allergy collapse toxicity pregnancy other drugs : diuretics
WHICH DRUGS INTERFERE WITH LA
MAOI : metabolises adreneline
tricyclics : hypertension
b blockers : reduce vasoC as on B2 adrenoreceptors
non potassium sharing diuretics : adreneline lowers K even more
WHEN TO AVOID LA WITH ADRENELINE
BP >200mmHg(systolic) / 155mmHg(diastolic)
WHICH DISEASES SHOULD YOU BE CAREFUL WITH WHEN USING ADRELEINE
CVS disease
hyperthyroidsm
hypertension
drug interactions
LOCAL COMPLICATIONS OF LA
fails to anaesthetise bells palsy - hit parotid gland pain IV injection = blanch/visual disturbance trismus - hit medial pterygoid prolonged anaesthesia haematoma - bleeding broken needle infection soft tissue damage contamination
WHAT TO DO IF SOMEONE GETS BELLS PALSY
give them eye patch
stay clam
say it will last a few hours then wear off
WHAT IS CHASING ANAESTHESIA
getting palatal anaesthesia by buccal infiltration then intrapapillary injection through until palate blanches
WHAT IS INTRALIGMENTARY ANAESTHESIA
inject into ging sulcus
WHAT IS INTRAOSSESOUS ANAESTHESIA
use stabident perforator to stab through mucosa and bone
then LA injected straight into the cancellous bone - miss out the dense cortical
fast but invasive
WHAT IS A TOPICAL JET INJECTOR
releases LA at high pressure so some goes into soft tissues
scary and loud but no needle(good for bleeding diathesis)
WHAT ARE ALTERNATIVE IDB TECHNIQUES
gow gates : open mouth inject higher to get trigeminal ganglion
akinosi technique : mouth closed and we pull cheek open, insert higher to get the trigeminal ganglion
WHAT IS THE WAND TECHNIQUE
less scary as its held like a pen and lot shorter needle
step on peddle to release LA at steady rate which reduces pain and human error
METHODS TO ACHIEVE SURFACE(SOFT TISSUE) ANAESTHESIA
physical = ethyl chloride
pharmacological = gel / controlled release devices / jet injectors
TENS /hypnosis
WHAT ARE THE USES OF TOPICAL GELS
pre injection clamp suture removal exfoliating primary teeth subgingival scaling incision of abscess
HOW TO ACHIEVE PALATAL ANAESTHESIA IN CHILDREN
chasing anaesthesia technique
HOW TO GIVE AN INTRALIGMENTARY INJECTION IN A CHILD
ultrashort 32 gauge needle at 30 degress to the long axis of the tooth, insert into the mesio-buccal ging sulcus and give 0.2ml per root
HOW TO DO A MENTAL BLOCK
inject in between the 2 premolars at the apexes
DISADVANTAGE OF A MENTAL BLOCK
may need additional labial infiltration as incisors may have crossover of supply at midline
ACTIONS TAKEN TO PREVENT COMPLICATIONS
aspirating
slow injection
dose limitation
HOW TO TREAT TOXICITY
stop BLS call medical assistance protect patient from injury monitor vital signs
HOW MUCH OF A CARTRIDGE FOR A BUCCAL INFILTRAION
1/4
HOW MUCH OF A CARTRIDGE FOR A PALATAL INFILTRAION
1/8
SITE OF LONG BUCCAL INJECTION
paralell to occlusal plane
distal and buccal to the last standing molar
called retro molar fossa
operator sits at 8oclock
WHICH NEEDLE USED FOR LONG BUCCAL INJECTION
long
WHAT EQUIPMENT NEEDED FOR AN LA TROLLEY SET UP
blue bin orange bin cotton wool roll topical LA cartridge long USP needle short USP needle black handle with rubber bung
HOW TO ASSEMBLE LA USP SYRINGE
remove sterile syringe from protective envelope
insert cartridge into syringe - gold end first
slide plunger to end of handle - make sure O-ring completely covered
line up the handle pins with syringe notches
push on
twist clockwise to lock
slide protective sheath backwards until clicks
remove needle cap
ready
HOW DOES THE LA USP SELF ASPIRATE
small protuberance at the bottom of the barrel which depresses the cartridge diaphragm throughout injection procedure
when injection pressure is released diaphragm goes back to normal - this causes back pressure in the needle resulting in aspiration
HOW CAN THE USER MANUALLY ASPIRATE THE LA USP SYRINGE
when the handle pulled back wards the o ring on the shaft creates a vaccuum providing active aspiration
HOW TO REPLACE A CARTRIDGE FOR A NEW ONE ON THE SAME LA USP SYRINGE
protective sheath to first holding position
ensure plunger fully retracted from cartridge
rotate handle anticlockwise to unlock
carefully pull 2 components straight apart
insert plunger with o ring back in to remove cartridge
insert new cartridge
WHY NOT USE THE SAME LA USP SYRINGE WITH MULTIPLE CARTRIDGES
can cause :
cannula penetration
canula breakage
self aspiration
HOW TO DISMANTLE AN LA USP SYRINGE
once procedure done protective sheath 2nd click twist and remove handle from barrel insert the plunger with silicone bung back in to remove cartridge dispose in sharps bins
HOW TO DISPOSE OF DIFFERENT LA NEEDLE HANDLES
white single use = medical waste
blue resuable = reprocessed according to manufacturers instructions
TROUBLESHOOTING WITH THE LA USP SYRINGE
if unloading required = unlock handle and separate - don’t bend
don’t hold hub to align bevel = may unlock syringe
