Difficulties and complicaitons LA Flashcards
Immediate problems and how to solve
anatomical variations (premed, sedation) faulty technique (repeat) alternative pathways of pulpal fibres inabilty to place needle appropriately local infection (try elsewhre) pain during injections (tissues not taut)
problems with equipment
Cartridge breakage
- can shatter if glass
- usually plastic sleeved or plastic cartriges
- use sleeved glass cartridges for intraligamentary injecitons
- rare, due to misalignment of syringe or blocked needle (always test and inject slowly)
Needle breakage
- rare
- do not insert to hub
- generally at site of bending, metal fault or hub
- remove immediately with artery forceps
- if not possible, refer to oral surgery for removal under GA
- radiographs at 2 angles and localising needles to remove
- keep all details and hub of needle
facial nerve paralysis
IAN nerve blocks
- either due to anatomy or wrong angle
- can enter parotid gland which contains the facial nerve
- may be partial or complete, resolves after LA wears off
- protect eye if lid affected
haematoma
dependant upon site
posterior superieor dental worst
- swelling an bruising
may lead to trismus
treatment for haematoma
- pressure
- prophylactic antibiotics if infection occurs
- trismus slowly resoves
- if not infected exercise
i
intravascular injection
adrenaline transporte systemucally
greater potentail for drug toxiity
allergy repsonces
- dilated hypersensitivity (urticaria, rash after 24 hours) to
- acute oedema (Rapid swelling of lipids/eyelids/tongue) or
- anaphylaxis (bronchospasm, decrease BP, collapse)
treatment for allergies
tment is dependant upon severity, ranging from antihistamines to 0.5- 1ml, 1:1000 adrenaline sc/im or hydrocortisone sodium succinate 100-300mg iv details later in course
toxic effects of adrenaline
systeemtic effects
high levesl - anxiety, trembling,headache,palpitations, disiness
prevention of toxic effects
slow injection
aspiraton
dose limitation
toxicisity of LA agent
- most likely to affect CNS (excitation at low dose, depressed at hihj)
- depressant on heart
- too much prolicaine could cause methaemoglobin aemai (Reduces RBC oxygen carrying capability)
max doses of LA
lignicaine 4.4mg/kg
prolicaine 6
articaine 7
mangament of patients with cardiac disease/hypertension
adrenaline increases froce and conctraction of rate of heart, increase cardiac excitabilti
sensible to limit to 2 cartridges
With unstabel angina
- adrelaine best avoilded
use prilocaine or lignocaine plain
- felypressin with prilocaine may cause coronary vasco constriction so restrict to 3 cartirdes
patietns taking other drugs and consequences
1) monoamine oxidase inhibitors (antidepressants)
- do not affect metabolism of exogenous catechnolamines, therefore no effect
2) tricyclic antidepressants
- inhibit uptake of catecholamines leading to increases intracerebral levels and improved mood
- no clinical evidence of adverse reactions with amount of adrenaline in LA
- may be wise to limit to 2 cartridges
3) phenothiazines (anti psychotic)
- adrenaline could potentiate hypotension
- no problem with normal dose range
4) non potassium sparing diuretic
- adrenaline exacerbates decrease in circulating potassium, so good to limit to 2
5) calcium channel blockers (eg verapamil)
- adrenaline could cause a hypokalaemia
- limit to 2 cartridges
6) anti Parkinson drugs
7) general anaesthesia (halothane)
- increases sensitivity to adrenaline
- decrease max dose by 50%
8) recreational drugs
- reduce amount or avoid local anaesthetic agents
9) Beta blockers
- limit 2 cartridges
- may lead t increase in systemic BP
- increased toxicity by reducing hepatic blood flow and inhibiting liver enzymes
10) Tricyclic antidepressants
pregnancy to avoud
prilocaine
- corsses placental barrier more readily
felypressin
- could leda to decrease in placental blood flow
bupivacaine
- avoid
