Medication Summary
The goal of pharmacotherapy is to achieve pain control perioperatively or postoperatively.
Local Anesthetics
Class Summary
Mepivacaine, bupivacaine and ropivacaine are all amide local anesthetics. They work by decreasing the permeability to sodium ions in neuronal membranes. This results in the inhibition of depolarization, blocking the transmission of nerve impulses. Mepivacaine has a fast onset, 5 minutes, but a short duration. Duration can be prolonged by 3 hours with 1:400,000 of epinephrine added. Bupivacaine and ropivacaine are both used for longer analgesia, more than 12 hours, but have a longer onset, about 20-plus minutes. Ropivacaine has a safer side-effect profile being less cardiotoxic.
Tetracaine is an ester local anesthetic. It works the same as the amides by decreasing the permeability to sodium ions in neuronal membranes. This results in the inhibition of depolarization, blocking the transmission of nerve impulses. Tetracaine has a slow onset with a long duration.
Mepivacaine (Carbocaine, Polocaine, Polocaine-MPF)
Mepivacaine decreases permeability to sodium ions in neuronal membranes. This results in the inhibition of depolarization, blocking the transmission of nerve impulses.
Bupivacaine (Marcaine, Sensorcaine, Sensorcaine MPF)
Bupivacaine decreases permeability to sodium ions in neuronal membranes. This results in the inhibition of depolarization, blocking the transmission of nerve impulses. It is a longer acting-agent. It is more cardiotoxic than ropivacaine.
Ropivacaine (Naropin)
Ropivacaine decreases permeability to sodium ions in neuronal membranes. This results in the inhibition of depolarization, blocking the transmission of nerve impulses. It is a longer-acting agent.
Tetracaine (Tetcaine, Tetracaine ophthalmic)
Tetracaine decreases permeability to sodium ions in neuronal membranes. This results in the inhibition of depolarization, blocking the transmission of nerve impulses. This is an option for longer analgesia.
-
Formation of brachial plexus rami, trunks, divisions, cords, roots and nerves.
-
Innervation of the arms and hands.
-
The cephalad-to-caudad approach.
-
Ultrasound image of the needle in plane with local anesthetic posterior to the axillary artery. Arrows = block needle, AA = axillary artery, LA = local anesthetic posterior to the artery.
-
Ultrasound orientation of the muscles, arteries, and nerves in a transverse view. Short axis (transverse view)-AA=axillary artery, Arrowheads=cords, AV=axillary vein, PMM=pectoralis major, PMIM=pectoralis minor 9-12 o‘clock is cephalad to artery=lateral cord, 6-9 o'clock is posterior=posterior cord, 3-6 o'clock is caudad is medial cord. Medial cord is often hard to visualize.
