Regional Anesthesia Flashcards
4 examples of aminoamide local anesthetics
- lidocaine
- bupivicaine
- ropivicaine
- mepivacaine
(the “i-caine”s)
4 applications for topical anesthesia
- larynx (during intubation)
- splash block prior to wound closure
- corneal (eye exam)
- EMLA cream for skin desensitization (for venipuncture or small mass removal)
potential CNS toxicity signs (5)
- Depression of cortical inhibitory pathways
- Impaired vision
- Tremors/seizures
- CNS depression
- Coma
Describe the MOA of local anesthetics (3 parts)
- Local anesthetic needs to penetrate into the cell to produce the its effects - Blockade of the Na+ channel - Prevents Na+ influx => no depolarization = no impulse transmission
Complication with inferior alveolar n. block
Spread and block of lingual nerve
2 pharmacological compound types of local anesthetics
- aminoesters
- aminoamides
EMLA cream produces anesthesia with a depth of approximately ______
1 cm
BE CAREFUL with infraorbital block in cats and
brachycephalic dogs due to _________
risk of ocular puncture
6 factors influencing the onset of local anesthetics
- lipophilicity
- pKa
- concentration
- dose and volume
- proximity to nerve
- type of nerve
T/F
local infiltration does not target a specific nerve
T
5 factors influencing the duration of local anesthetics
- vascular effect
- tissue blood flow
- vasoconstrictor?
- dose
- affinity to the Na receptor
Landmarks in small animals for epidural anesthesia (3)
- Iliac crest
- Medial sacral crest
- Spinous process of L7
Why is the lumbosacral space used for small animal epidural anesthesia and the sacrococcygeal space used in large animals?
the spinal cord ends at L7 in small animals while in large animals the spinal cord ends at L7
indication for local infiltration anesthesia
Anesthesia for skin and underlying
tissues
_________ anesthetics are hydrolyzed by the cholinesterase enzyme (plasma and liver)
aminoesters
DO NOT use lidocaine with epinephrine when there is not ___________
collateral circulation
________ anesthetics undergo Hepatic metabolism (microsomal
enzymes)
aminoamides
3 target nerves in lumbar paravertebral nerve block
T13, L1, L2
__________ most commonly used in small animals for epidural anesthesia
Lumbo-sacral space
“Loss of Resistance” technique for epidural anesthesia (4)
1. Advance the Tuohy needle until the interarcuate ligament is perceived 2. Remove the stylet and attach the syringe to the hub 3. Apply small pressure to the plunger and advance the needle through the interarcuate ligament 4. The resistance to the injection of air drops suddenly when needle enters the epidural space
CNS signs of LA toxicity will appear before CV signs, except for with __________ toxicity
Bupivacaine
the epidural space is between the ________ and ________
- interarcuate (flavum) ligament
- duramater
what is the benefit of peripheral nerve blocks?
Injection of a small volume of local anesthetic produces a great area of desensitization