Nagelhout videos- Local anesthetics

Question 1

What does adding co2 to a local anesthetic do? (Carbonating the local anesthetic)

Answer 1

• diffuses the solution into the nerve immediately
• once inside the nerve, dissociates and the co2 makes the inside of the nerve more acidic
• local anesthetic becomes more ionized INSIDE the nerve, where it is going to exert its action

-quicker onset and more dense block

Question 2

When will the patient typically experience s/s LAST

Answer 2

within 1 minute of injection (usually)

Question 3

Why might you just go straight to sux instead of versed if a person is seizing from LAST

Answer 3

bc within 60 seconds they will be still and you can intubate them (they are anesthetized by the local in the brain so dont worry about them remembering)

-versed will stop the seizure sure, but after the seizure stops, the CNS goes into a depressive state (to try and recoup energy that was just expent) and the versed will compound that

Question 4

What are some things you want to know/have when going to do a PNB

Answer 4

• where’s the resuscitation equipment
• do they have a working IV
• where’s the lipid emulsion if you were to need it and how much of a bolus would you give based on pt’s weight (1.5ml/kg)
• have sux and midaz with you

Question 5

Why is it important to aspirate 5cc and then wait and aspirate again (other than making sure your not hitting a vessel)

Answer 5

• should be assessing the patient during this time as well for any s/s LAST
• might be prudent to ask them to let you know if they have any ringing in the ears/metallic taste/numb mouth

Question 6

First thing if you expect LAST

Answer 6

-call for extra help

Question 7

T/F- pregnancy enhances the effects of local anesthetics

Answer 7

true

Question 8

T/F- plasma half life of local anesthetics is higher in infants than adults

Answer 8

true

-bc infants are big bags of water so higher volume of distribution

Question 9

If your mixing 2 local anesthetics (say one has a faster onset and the other will kick in when that one starts to wear off) how would you go about determining the max doses if your using BPV and lido

Answer 9

half their max doses bc your only doing half and half (additive effect)

normal lido = 5, so say max is 2.5mg/kg

normal bpv = 2mg/kg so say max is 1mg/kg

Question 10

If you give a block and use the max dose and then the surgeon wants to inject local at the end of the procedure; can he?

Answer 10

as long at 90 minutes has elapsed, the dose can be repeated

Question 11

So pts with a big pregnant belly, compress the epidural space and leads to greater spread of the local anesthetic; therefore you can say they are more sensitive to the local anesthetics

1st trimester moms are also more sensitive to local anesthetics… why?

Answer 11

hormones - progesterone

Question 12

Why is our max dose of lidocaine 5mg/kg and if plastics give tumescent its 35-55mg/kg ?

Answer 12

Bc they are injecting into the fat which doesn’t a great amount of blood supply
>& they use epi to keep it there
>then they suck it all out with the liposuction wand