Local Anesthesia Flashcards
What are the common local anesthetic agents used in vet med?
- Esters
- Cocaine
- Procaine
- Chloroprocaine
- Proparacaine - Amides
- Lidocaine
- Mepivacaine
- Buprivacaine
Local anesthesia refer to?
The loss of pain sensation & movement in an area of the body due to a blockage of the nerve conduction
Local anesthetics mechanisms of action
Interferes with movement of sodium ions across neuronal cell membranes by blocking the sodium channels which prevent the nerve response.
Local anesthetics indications of use
- Bathe the nerve in the local anesthetic drug
- Do not inject the actual nerve as this can cause temporary and/or permanent nerve damage
- Common to use when an animal has a wound that needs a quick clip/clean/suture where there is no need for general anesthesia
- Common to use during skin biopsies
- Common to use to diagnose limb lameness in a horse
How do yo diagnose limb lameness in a horse?
You numb different parts of the leg to determine where the lameness is coming from. Once you have numbed the lame area the horse should stop limping/lifting the limb since ideally there should be no pain. You start by numbing the navicular bone first than move to the pastern joint, than Fetlock Joint and continue your way up.
Ester local anesthetic agent include?
- Cocaine
- Procaine
- Chloroprocaine
- Propracaine
Local anesthetics Esters affects/uses
- Not super common in vet med
- Numbing effects do not last long
- Ideally used to numb the mucous membrane of the eye and/or nose
- Not ideally injected
Procaine is most commonly used on which body part?
Eyes
Proparacaine is most commonly used on which body part?
The nose
The local anesthetics Amides include?
- Lidocaine
- Mepivacaine
- Bupivacaine
Amides have a longer or shorter lasting effect?
Longer lasting effect
Amides are metabolized in the?
Liver
Lidocaine effects?
- 2x as potent as Procaine
- Rapid onset about 5 minutes
- Last about 1.5 - 2 hours
- Common to use during dental nerve blocks
- Common to combined w/ Bupivacaine to take of advantage of Lidocaines rapid onset & Bupivacaine high potency
Lidocaine is commonly used during?
Dental nerve blocks
Lidocaine is commonly used in combination with?
Bupivacaine
Lidocaine is considered what type of local anesthetic?
Amide
Mepivacaine uses/effects
- 2x as potent as Procaine
- Rapid onset about 5 minutes
- Last about 1.5 - 3 hours
- Does not sting as much as Lidocaine when administered subcutaneously
- Used during lameness exams for horses
Mepivacaine is commonly used?
During lameness exams for horses
Mepivacaine is what type of local anesthetic?
Amide
Bupivacaine effects/uses
- 8-10x as potent as Procaine
- Slow Onset
Lasts 4-6 hours - Common to use during dental nerve blocks
- Provides anagelsia which is why its preferred during dental extractions
Bupivacaine is common to use?
During dental nerve blocks
Lidocaine last?
1.5-2 hours
Lidocaine effect are seen in?
About 5 minutes
Mepivacaine last
About 1.5 - 3 hours
Mepivacaine effects onset in?
Rapid onset - 5 minutes
Bupivacaine effects last?
4 - 6 hours
Bupivacaine has a slow or rapid onset?
Slow Onset
Local anesthetics adverse effects?
- Tissue Irritation
- Allergic Reactions
- Nerve Trauma
- Respiratory Paralysis
- System Toxicity
Local anesthetic signs of system toxicity
- Muscle Twitching
- Sedation and/or hyper-excitability
- Seizures
- Respiratory Depression
What is the toxic dose in cats for local anesthetics?
8-10mg/kg
Nerve Block refers to
Administration of local anesthetics into tissues in proximity to and around a large nerve
Line Block refers to?
Multiple local anesthetic injections made around an area innervated by multiple small nerves
Regional injections refer to?
Technique where local anesthetics is injected in the proximity of the spinal cord or into a major nerve plexus
Localized infiltration refers to?
Anesthetized terminal nerve endings which as a limited area of effect.
Administered inttradermally, SC, or between muscle planes.
Examples of localized infiltration technique of local anesthetics administration are?
- Nerve Block
- Line Block
Examples of regional injection techniques are?
- Epidural Block
- Paravertebral Block
Examples of topical applications of local anesthetics?
- Drops in the eye
- Lidocaine on the glottis opening during a cat intubation