Complications and Contraindications of LA

Question 1

What type of LA is lidocaine?

Answer 1

amide type

Question 2

What is the concentration of lidocaine used and what is the concentration of vasoconstrictor?

Answer 2

Lidocaine = 2%
Adrenaline = 1:80000

Question 3

What type of LA are prilocaine and articaine?

Answer 3

amide

Question 4

What is the vasoconstrictor used with prilocaine?

Answer 4

felypressin (octapressin) 1.2micrograms

Question 5

What is the concentration of articaine used?

Answer 5

4%

Question 6

What are the systemic complications of LA that present as signs/symptoms?

Answer 6

fainting
palpitations
cold sweats
restlessness
excitation
trembling
weakness

Question 7

What is the possible concentrations of adrenaline used with articaine?

Answer 7

1;100000
1;200000
1;400000

Question 8

What is articaine better than lidocaine in?

Answer 8

infiltrations
fast onset, lasts longer

Question 9

What is the cause of these systemic signs?

Answer 9

lack of oxygenated blood to brain due to vasoconstrictor

Question 10

What drugs do LAs interact with?

Answer 10

M.A.O.I (adrenaline)
tri-cyclics (adrenaline)
b-blockers (adrenaline)
non potassium sparing diuretics
cocaine

Question 11

What causes allergies in LAs mostly?

Answer 11

preservatives such as
methylparaben
sodium metabisulphite

Question 12

What are the signs of toxicity?

Answer 12

convulsions
loss of consciousness
respiratory depression
circulatory collapse

Question 13

How much lidocaine does each cartridge usually contain?

Answer 13

44mg

Question 14

What should you avoid giving to pregnant people?

Answer 14

octapressin as this has the potential to induce labour

felypressin

Question 15

What is the max dose of lidocaine, articaine, and prilocaine?

Answer 15

lidocaine = 4.4mg/kg
articaine = 7mg/kg
prilocaine = 6mg/kg

Question 16

When should you be cautious giving adrenaline to a patient?

Answer 16

CVD
hyperthyroidism (thyroid crisis)
drug interactions
phaeochromocytoma (hypertension)

Question 17

What drugs interact with adrenaline?

Answer 17

MAOI
tricyclic antidepressants
b blockers
non potassium sparing diuretics
halothane (general anaesthesia)
cocaine

Question 18

What are complications that may occur local to injection site?

Answer 18

prolonged anaesthesia pain
trismus
haematoma
intra-vascular injection
blanching
facial paralysis
broken needle
infection
soft tissue damage
contamination

Question 19

How can prolonged anaesthesia occur?

Answer 19

direct trauma from needle (multiple passes with the same needle)
chemical trauma for direct injection

Question 20

What LA did most nerve injury come from?

Answer 20

articaine (4%)

Question 21

What is the first line choice of LA?

Answer 21

2% lidocaine with adrenaline

Question 22

How does trismus occur?

Answer 22

damage/irritation to medial pterygoid

Question 23

What can you prescribe for trismus?

Answer 23

for profound cases =
anti-inflammatory
muscle relaxant

Question 24

What is facial palsy?

Answer 24

unilateral motor nerve paralysis

Question 25

What is the cause of facial palsy?

Answer 25

IANB into parotid gland too far posteriorly

Question 26

What differentiates a stroke from a palsy?

Answer 26

stroke patients can wrinkle both sides of the forehead as upper motor neurons defects spare upper branches of facial nerve

Question 27

What are the signs of intra-arterial injections?

Answer 27

skin blanching
visual disturbances

Question 28

How to avoid intra-arterial injections?

Answer 28

aspirate
introduce drug slowly