Maverick Modules (5-6) Drugs & Toxicity Basics

Question 1

____ of Marcaine or Ropivacaine should be utilized in fractionated dosing, aspirating every ____ cc’s.

Answer 1

20 - 30 cc’s

Aspirate every 5 cc’s

Mod 5

Question 2

What is Marcaine?

Answer 2

Bupivacaine with epinephrine

Mod 5

Question 3

How do blocks work at the cellular level?

Answer 3

Na⁺ channel blockade and thus blockade of impulse transmission

Mod 5

Question 4

Potency is associated with ____.

Answer 4

Lipid Solubility

Mod 5

Question 5

What determines the onset of a local anesthetic?

Answer 5

pKa (ionized constant)

Mod 5

Question 6

The higher the pKa, the ____the onset.

Answer 6

slower (slower to take effect, but that also means a longer duration)

Mod 5

Question 7

Duration of a block is primarily effected by what factor?

Answer 7

Protein binding

Mod 5

Question 8

The higher the degree of protein binding, the ____ the duration of the block.

Answer 8

longer

mod 5

Question 9

Increased patient age will increase local anesthetic ____.

Answer 9

Duration

mod 5

Question 10

How are amides eliminated?

Answer 10

Hepatic metabolism

mod 5

Question 11

How are esters eliminated?

Answer 11

Plasma cholinesterases

mod 5

Question 12

Which anesthetic class has a greater propensity for allergic reactions? Why?

Answer 12

Esters (due to PABA preservative)

Mod 5

Question 13

Mass does not increase the ____ of the block, but will increase the ____ of the block.

Answer 13

density ; duration

mod 5

Question 14

What is the main effect of adding Epi to your regional block?

Answer 14

Prolongs duration and intensity of the block by vasoconstriction at the microvascular level

mod 5

Question 15

What is the standard recommended epinephrine dose for regional techniques?
What is the Maverick recommended dose?

Answer 15

• Standard = 1:200,000 = 5 mcg/mL (this potentially could cause ischemia)
• Maverick = 1:400,000 = 2.5 mcg/mL (you will still get the same duration of block)

mod 5

Question 16

Can epinephrine be used on “fingers, nose, and toes”?

Answer 16

Yes

(Old info suggested not)

Plastic surgeons use Epi in their local ALL THE TIME

Mod 5

Question 17

What effect does dexamethasone have on regional blocks?

Answer 17

Decadron = ↑ block duration
could be related to systemic anti-inflammation (this will increase duration even when decadron is give IV)

mod 5

Question 18

What dose of dexamethasone is used as an adjunct for regional blocks?

Answer 18

4 - 8 mg

mod 5

Question 19

How does clonidine serve as an adjunct for local anesthetics?

Answer 19

Prolongation of block (but not as available, and requires heavy dilution)
- could have synergistic local pharmacokinetic action - but MOA unknown

Mod 5

Question 20

What is the dose for Clonadine in a regional block?

Answer 20

1mcg/kg

mod 5

Question 21

What is the primary purpose of local anesthetic adjuncts?

Answer 21

Prolongation of block

mod 5

Question 22

How do Opioids serve as an adjunct for regional blocks?

Answer 22

Trick question, there have been no studies to date showing an advantage of adding opioids to a regional block
- intra-articular injections are beneficial - prolonged duration and increased quality

mod 5

Question 23

____ and ____ of absorption are the primary determinants of the occurrence of local anesthetic toxicity.

Answer 23

rate and extent of absorption

mod 6

Question 24

Rate the following from Highest absorption (and thus greatest risk of toxicity) to Lowest absorption.

• Femoral
• Sciatic
• Lumbar Plexus
• Intercostals
• Epidural
• Brachial Plexus
• Caudal

Answer 24

1. Intercostals (Highest)
2. Caudal
3. Epidural
4. Brachial Plexus
5. Sciatic
6. Lumbar Plexus
7. Femoral (Lowest)

Mod 6

Question 25

How would the typical symptoms present for CNS toxicity secondary to LA’s?
What is the progression typically?

Answer 25

Excitatory

Disorientation/incoherence → Tonic-clonic seizures → respiratory depression → arrest

mod 6

Question 26

Increases in ____ and ___ typically precede the hypotension, arrhythmias, and cardiac arrest associated with local anesthetic toxicity.

Answer 26

↑ HR and BP

mod 6

Question 27

What should you do if you suspect a LA toxicity?

Answer 27

• Aspirate for blood
• Pull needle out
• Place pressure on the vessel
• Protect airway
• Push 20% lipids

mod 6

Question 28

Not having 20% lipid infusions readily accessible with the block cart is considered ____.

Answer 28

Negligent

mod 6

Question 29

Intralipid doses

Answer 29

Literature says bolus: 1.5 mL/kg
Infusion: 0.25 mL/kg/min
…but basically just keep bolusing them until you get a HR and BP

mod 6

Question 30

What is the recommended dose of clonidine as an adjunct for regional anesthetics?

Answer 30

1 mcg/kg

Question 31

In the event of local anesthetic-induced cardiac arrest that is unresponsive to standard therapy, what drug should be given?

Answer 31

IntraLipid 20% bolus and infusion.

Question 32

What maximum dose of Intralipid is recommended?

Answer 32

8mL/kg