Nerve & Local Anesthetics focused Flashcards
Function of type A fibers
alpha- proprioception, motor
beta- touch, pressure
gamma- muscle tone
delta- pain, cold temp, touch
Function of type B fibers
preganglionic autonomic vasomotor (SNS)
Function of type C fibers
Postganglionic vasomotor (SNS) pain, warm, cold temp, touch (dorsal root)
Which types of fibers are myelinated?
Type A have HEAVY myelination
Type B have light myelination
Which types of fibers are unmyelinated?
Type C fibers
What is the diameter of type A fibers: Alpha: Beta: Gamma: Delta:
Alpha - 6-22mm
Beta - 6-22mm
Gamma - 3-6mm
Delta - 1-5mm
What is the diameter of type B fibers?
<3mm
What is the diameter of type C fibers?
SNS - 0.3-1.3mm
Dorsal root - 0.4-1.2mm
What is the block onset of type A fibers: Alpha: Beta: Gamma: Delta:
Alpha - Last
Beta - Intermediate
Gamma - Intermediate
Delta - Intermediate
What is the block onset of type B fibers?
Early
What is the block onset of type C fibers?
Early
What are the 4 subtypes of type A fibers?
Alpha
Beta
Gamma
Delta
What type of fibers are blocked first?
Type B
What are 5 ester local anesthetics?
procaine chloroprocaine tetracaine cocaine benzocaine
What are 6 amide local anesthetics
lidocaine mepivacaine prilocaine bupivacaine ropivacaine articaine
Maximum dose of lidocaine
4mg/kg
Maximum dose of Mepivacaine
4mg/kg
Maximum dose of Bupivacaine
3mg/kg
Maximum dose of Ropivacaine
3mg/kg
Maximum dose of Procaine
12mg/kg