Local Anesthesia Flashcards
What is the drug of choice for local anesthesia in veterinary medicine?
Bupivacaine
0.5% solution or 5mg/ml
What kind of blocks take care of each arch?
Caudal blocks
What are the possible reactions to local anesthetics?
Toxicity to skeletal muscle
Anaphylactic reactions
Permanent nerve damage
What is a simple rule to avoid toxicity in dogs and cats?
Never exceed 2.0 mg/kg
What is the least effective method of local anesthesia?
Infiltration blocks
When are infiltration blocks used?
After the procedure in an attempt to reduce postoperative discomfort
What do infiltration blocks do?
Only effective in the area of infiltration
What is the advantage of regional anesthesia?
The ability to block entire quadrants
What are the disadvantages of regional nerve blocks?
loss of sensation and function of the area blocked
postoperative self-inflicted injury
Where is the maxilla blocked?
The rostral or caudal maxilla
What does the rostral maxillary infiltrate?
The infraorbital nerve
What does the rostral maxillary block anesthetize
INcisors Canines First three premolar Maxillary bone Surrounding soft tissue
What does the caudal maxillary block anesthetize?
Both maxillary nerve
Sphenopalatine nerve/ganglia
All maxillary teeth on the side of the infiltration
Adjacent bone & soft tissue
What does the rostral mandibular block anesthetize?
The inferior alveolar nerve
Which block has limited effectiveness and the caudal block is recommended instead?
The rostral mandibular block
What does the caudal mandibular block anesthetize?
Incisors
Canines
First two premolars
Adjacent bone and soft tissue
What does the caudal mandibular block infiltrate?
The inferior alveolar nerve on the lingual aspect of the mandible
When performing the rostral maxillary and caudal maxillary blocks, retract the lip dorsally and palpate where?
Just dorsal to the distal root of the maxillary 3rd premolar
What is beneath the vestibular mucosa and is palpated as a large cylindric band that exits the infraorbital canal and is retracted dorsally with a digit of the hand not holding the syringe?
The infraorbital neurovascular bundle
How is proper insertion confirmed?
By gentle movement of the syringe as the needle hits the infraorbital canal wall
Why is it important that the syringe and needle are parallel to the dental arch line of the maxilla?
The infraorbital canal is very short (especially in cats and brachiocephalic dogs)
Where does the rostral mandibular block infiltrate?
The rostral extent of the inferior alveolar nerve just before it exits the middle mental foramen
What is the landmark for the rostral mandibular block?
Mandibular labial frenulum
What is retracted ventrally?
The frenulum
For the rostral mandibular block, where is the needle inserted?
At the rostral aspect of the frenulum
For the rostral mandibular block, after the needle is inserted where is it advanced?
Along the mandibular bone at a 30-degree angle to just enter the canal
How is the caudal mandibular block performed?
By palpating extra orally the notch just dorsal to the angle of the mandible and ventral to the condylar process
Why is it important that the needle tip is located caudal to the foramen and rostral to the angular process of the mandible?
The inferior mandibular nerve is located outside of the mandibular canal
When advancing the needle for the caudal mandibular block, the third molar in the dog and the first molar in the cat are used as landmarks, but the first molar is missing in cats, what is done instead?
The mandibular notch is palpated, the position of the first molar is approximated, and the needle is directed to the injection site
What is an alternative method used for a landmark for the caudal mandibular block?
The lateral canthus of the eye
An imaginary line is drawn from the lateral canthus of the eye directly to the ventral mandible
Why is it important to be careful not to anesthetize the tissues of the tongue?
The patient could wake up, not feel its tongue and chew its tongue
If the tongue tissues are anesthetized, how is it treated?
The distraction of the patient
Sedation
General anesthesia until the regional anesthesia wears off or dysphoria stops
What is the best treatment for anesthetizing the tongue?
Prevention by keeping the bevel of the needle pointed toward the mandible and staying right on the mandible as the needle is advanced
Because of the opioid receptors in the peripheral nervous system, what opioid has been shown to effectively double the analgesic duration when combined with bupivacaine?
Buprenorphine
