LA complications Flashcards
what are the 3 types of LA most commonly used
- lignocaine = most used
- can use pressin as well
- or artisane which is general in 4%
what is lidocaine
- amide type LA
- lidocaine HCl 2% = or can get 3% one without vasoconstrictor
- vasoconstrictor = adrenaline, 1:80,000
- uses = infiltrations/blocks and others
what is citanest
- chemical name is prilocaine HCl 3%
- comes plain or octapressin vasoconstrictor in it = 1.2mcg
- amide LA
- uses = infiltrations, block and others
what is articaine
- 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
how long is lignocaine infiltration pulpal anaesthesia
- 60 mins
what is lignocaine block pulpal anaesthesia
- 90 mins
what is articaine infiltration pulpal anaesthesia
- up to 120 mins
what is articiane block pulpal anaesthesia
- 75 mins
what is prilocaine infiltration pulpal anaesthesia
- 30-45 mins
what is prilocaine block pulpal anaesthesia
- 60 mins
what are systemic complications of LA
- psychogenic/stress
- interaction with other drugs
- cross infection
- allergy
- collapse
- toxicity
- pregnancy
what is the most common type of systemic complication with LA
- psychogenic
- especially common with anxious patients
what can happen with psychogenic complications
- can have = faint, palpitations, cold sweat, restlessness, excitation, trembling, weakness
what is the natural response to fainting
- to remain lying down so oxygen stays at head, don’t want to get up
what do palpitation feel like
- heart is bounding out of chest
how can patient get weakness from LA
- from standing up too quickly
what is the cause of fainting
- lack of oxygenated blood to the brain
what are the clinical features of fainting
- light-headedness
- pallor
- beads of sweat at lips, nose and temple
- bradycardia = slow pulse
- nausea
- pupil dilation
what is the management of fainting
- 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
what are some drugs that can interact with LA
- 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
what do patients often mistake for being allergic to LA
- feeling faint or bounding heart but that is just due to adrenaline
what wa the main cause of allergy of LA historically
- the latex bung but hat is no longer made of let
what are most LA allergies caused by
- preservatives/antioxidants
- methlypraben/sodium bisulphate
what can patient get if they are allergic
- skin rashes of respiratory effects of even full blown anaphylaxis but this is rare
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
how can toxicity be caused by LA
- given too much
what are the effects of toxicity of LA
- convulsions
- loss of consciousness
- respiratory depression
- circulatory collaps
what can toxicity be mistaken for
- fainting
- both cause circulatory depression and loss of consciousness so need to know the difference between them