Local Anesthesia Flashcards
Which is harder to block myelinated or non-myelinated?
non-myelinated
Block is proximal to distal for peripheral fibers, so how does it go with core and mantle?
mantle–>core
Out of the alpha category which is the easiest to block?
gamma
Which is the easiest fiber to block overall?
B fibers
What are the first signs you see that a spinal/epidural anesthesia is working vs the first signs you see that a peripheral nerve block is working?
spinal/epidural
-pain–>sensory–>motor
peripheral
-first sign may be lack of proximal muscle coordination
What type of states of the voltage gated ion channels do local anesthetics prefer to bind?
-inactivated and open rather than resting
Where do local anesthetics bind?
-R site
What type of anesthetics can cross the membrane what type can bind the active site?
- uncharged-cross
- charged-bind
What determines onset time?
pH and pKa
What determines potency?
Lipid solubility
What determines duration?
protein binding
-local tissue proteins-can bind create a sink that slowly released into the nerve-more binding longer they will last
How can you change onset time?
raise the pH of the solution by adding sodium bicarbonate
-use a drug with a lower pKa
What types of drugs is the vasoconstricting power of epinephrine most useful for?
Drugs not highly protein bound like:
Lidocaine, Mepivicaine
What types of drugs is the vasoconstricting power of epinephrine less useful for?
Highly protein bound drugs
-ropivacaine, bupivacaine
What can IV lidocaine treat?
arrthymias
