Nerve blocks

Question 1

Esters vs amides based on name

Answer 1

Amino esters - one i in name

Amino Amides - 2 is in name

Question 2

Esters vs amides

Onset
duration
allergy risk
Local anaesthetic systemic toxicity risk
metabolism
volume of distribution
pKa

Answer 2

Question 3

Which types of nerves are blocked most readily by local anaesthetic?

Why use cold block / ice (or movement) to test nerve block

Answer 3

Temp fibres blocked after pain -> can be more sure of block

Question 4

Options to prolong a nerve block

Answer 4

Adrenaline - vasoconstrics -> less blood flow -> slows distribution / absorption

Clonidine - enhances effects

Dexmed

Dexamethasone

Question 5

Which locations of local anaesthetic have the highest systemic absorption / lowest

Answer 5

Question 6

What is LAST in local anaesthetic

Answer 6

Local anaesthetic systemic toxicity

Importantly cardiac electrophysiological and contractile dysfunction

Question 7

Key drug for circulatory collapse with LAST

Answer 7

Intralipid 20% 1.5mg/kg in 1 min

followed by 15mg/kg over 1 hour

Question 8

How does intralipid work

Answer 8

Increases LA clearance from cardiac tissue

Question 9

Common genetic issue which means LA doesnt work properly

Answer 9

Ehlers danlos syndrome