Maverick Modules (5-6) Drugs & Toxicity Basics Flashcards
____ of Marcaine or Ropivacaine should be utilized in fractionated dosing, aspirating every ____ cc’s.
20 - 30 cc’s
Aspirate every 5 cc’s
Mod 5
What is Marcaine?
Bupivacaine with epinephrine
Mod 5
How do blocks work at the cellular level?
Na⁺ channel blockade and thus blockade of impulse transmission
Mod 5
Potency is associated with ____.
Lipid Solubility
Mod 5
What determines the onset of a local anesthetic?
pKa (ionized constant)
Mod 5
The higher the pKa, the ____the onset.
slower (slower to take effect, but that also means a longer duration)
Mod 5
Duration of a block is primarily effected by what factor?
Protein binding
Mod 5
The higher the degree of protein binding, the ____ the duration of the block.
longer
mod 5
Increased patient age will increase local anesthetic ____.
Duration
mod 5
How are amides eliminated?
Hepatic metabolism
mod 5
How are esters eliminated?
Plasma cholinesterases
mod 5
Which anesthetic class has a greater propensity for allergic reactions? Why?
Esters (due to PABA preservative)
Mod 5
Mass does not increase the ____ of the block, but will increase the ____ of the block.
density ; duration
mod 5
What is the main effect of adding Epi to your regional block?
Prolongs duration and intensity of the block by vasoconstriction at the microvascular level
mod 5
What is the standard recommended epinephrine dose for regional techniques?
What is the Maverick recommended dose?
- 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
Can epinephrine be used on “fingers, nose, and toes”?
Yes
(Old info suggested not)
Plastic surgeons use Epi in their local ALL THE TIME
Mod 5
What effect does dexamethasone have on regional blocks?
Decadron = ↑ block duration
could be related to systemic anti-inflammation (this will increase duration even when decadron is give IV)
mod 5
What dose of dexamethasone is used as an adjunct for regional blocks?
4 - 8 mg
mod 5
How does clonidine serve as an adjunct for local anesthetics?
Prolongation of block (but not as available, and requires heavy dilution)
- could have synergistic local pharmacokinetic action - but MOA unknown
Mod 5
What is the dose for Clonadine in a regional block?
1mcg/kg
mod 5
What is the primary purpose of local anesthetic adjuncts?
Prolongation of block
mod 5
How do Opioids serve as an adjunct for regional blocks?
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
____ and ____ of absorption are the primary determinants of the occurrence of local anesthetic toxicity.
rate and extent of absorption
mod 6
Rate the following from Highest absorption (and thus greatest risk of toxicity) to Lowest absorption.
- Femoral
- Sciatic
- Lumbar Plexus
- Intercostals
- Epidural
- Brachial Plexus
- Caudal
- Intercostals (Highest)
- Caudal
- Epidural
- Brachial Plexus
- Sciatic
- Lumbar Plexus
- Femoral (Lowest)
Mod 6
How would the typical symptoms present for CNS toxicity secondary to LA’s?
What is the progression typically?
Excitatory
Disorientation/incoherence → Tonic-clonic seizures → respiratory depression → arrest
mod 6
Increases in ____ and ___ typically precede the hypotension, arrhythmias, and cardiac arrest associated with local anesthetic toxicity.
↑ HR and BP
mod 6
What should you do if you suspect a LA toxicity?
- Aspirate for blood
- Pull needle out
- Place pressure on the vessel
- Protect airway
- Push 20% lipids
mod 6
Not having 20% lipid infusions readily accessible with the block cart is considered ____.
Negligent
mod 6
Intralipid doses
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
What is the recommended dose of clonidine as an adjunct for regional anesthetics?
1 mcg/kg
In the event of local anesthetic-induced cardiac arrest that is unresponsive to standard therapy, what drug should be given?
IntraLipid 20% bolus and infusion.
What maximum dose of Intralipid is recommended?
8mL/kg
