Anaesthesia & analgesia for dental & GI cases Flashcards
1
Q
What nerve provides sensory innervation to the head?
A
- trigeminal
2
Q
How do LA’s work?
A
- block Na channels which are necessary for membrane depolarisation
- therefore, block transmission of the stimulus via A & C fibres
3
Q
Benefits of LA?
A
- allow for balanced anaesthesia
- reduce post-op pain and intraoperative nociception
- reduces requirements for maintenance agents
4
Q
Common LA combination
A
- lidocaine + bupivicaine
5
Q
Contraindications of LA
A
- infection at site of injection
- neoplasia in region of injection
6
Q
What three separate tracts does the trigeminal nerve emerge as?
A
- ophthalmic
- maxillary
- mandibular
7
Q
What nerve tract innervates the teeth and the bone adjacent to the teeth within the maxilla?
A
- superior alveolar nerve
8
Q
What tissues and teeth are innervated by the SAN?
A
- caudal branch innervates pulp, periodontal ligament and adjacent alveolar bone of maxillary third and fourth premolars, first and second molars
- rostral branches innervates pulp, periodontal ligament and adjacent alveolar bone of maxillary incisors, canines and first and second pre-molars
9
Q
What tissues does the infraorbital nerve innervate?
A
- afferent innervation to buccal maxillary soft tissue rostral to infraorbital foramen
- does not innervate teeth or bone
10
Q
What is the buccal nerve a branch of?
A
- Mandibular
11
Q
What does the buccal nerve innervate?
A
- soft tissues on buccal aspect of maxilla, caudal to infraorbital foramen
12
Q
LA of which nerve apart from SAN is required for surgical extraction of maxillary third and fourth premolars, and first and second molars?
A
- buccal nerve
13
Q
What tissues do the major and minor palatine nerves innervate?
A
- palatal soft tissues
- major = hard palate
- minor = soft palate
14
Q
How would you perform an infraorbital block?
A
- LA at opening of infraorbital foramen or insert needle into canal
- anaesthetises rostral maxillary soft tissues
- some branches of SAN may become anaesthetised with this technique
- will not provide anaesthesia for any extraction of teeth
15
Q
How would you perform a caudal maxillary block?
A
- LA on caudal aspect of maxilla either intraoral or cutaneously
– cutaneous: needle between caudal maxilla and rostral aspect of the coronoid process of mandible
16
Q
What can the caudal maxillary block anaesthetise?
A
- ION, SAN and major and minor palatine nerves
- unlikely to affect buccal nerve and so all ipsilateral maxilla with be anaesthetised with exception of buccal soft tissues on caudal aspect from maxillary third premolar caudally
- additional anaesthetic will need to be deposited on buccal aspect of caudal extent of maxilla
17
Q
What single nerve is responsible for afferent innervation of the mandible?
A
- inferior alveolar nerve
- individual alveolar nerves branch dorsally through a short section of bone to each individual tooth to innervate tooth structures and adjacent bone
- at rostral end of mandible = three mental foramina where mental nerves leave mandibular canal to innervate soft tissues of rostral lower lip
18
Q
What tissues does the mylohyoid nerve innervate?
A
- buccal mandibular soft tissues caudal to mental nerves
- important for surgical extraction of teeth caudal to mandibular third premolar
19
Q
what tissues does the lingual nerve innervate?
A
- tongue -> local infusion more appropriate than LA
20
Q
How is a mental nerve block carried out?
A
- LA at opening of mental foramen or insert needle into mental foramen
21
Q
Why is the mental nerve block not useful for dental surgery/cases?
A
- mental nerves only supply soft tissues of rostral mandible so only tissues anaesthetised using this technique i.e. no real application
22
Q
How is an intraoral caudal mandibular block performed?
A
- needle inserted on lingual aspect of mandible caudal to last tooth (caudal mandibular foramen approx. halfway between last tooth and angular process of mandible)
23
Q
How is a ventral cutaneous caudal mandibular block performed?
A
- place LA on lingual aspect of mandible
24
Q
What does the caudal mandibular block provide LA of?
A
- the whole of the IAN and therefore ipsilateral bone and teeth
- also anaesthetises all mental nerves and so all of soft tissue rostral to mental foramina
- won’t anaesthetise the myelohyoid nerve (need LA on ventro-buccal aspect of mandible for this) which is required for surgical extraction of third premolar tooth caudally
25
Signs of LA systemic toxicity under GA
- tachycardia
- bradycardia
- respiratory depression
26
Tx for LA systemic toxicity under GA
- intralipid IV
27
What can insertion of LA needle into bone canal cause?
- fluid injected = increased pressure in canal = neuropraxia, chronic pain or lack of sensation
28
What can occur if LA injected directly into nerve?
- nerve damage
- aim is perineural
- if pressure encountered during injection = withdraw and redirect needle
29
What nerve can also be anaesthetised with a mandibular nerve block?
- lingual nerve -> may affect motor function, sensation, taste + saliva on rostral two thirds of tongue
30
How might you prevent inadvertently deep penetration of LA needle during intraoral approach to caudal maxillary block to reduce risk of intra or periocular injection?
- bend needle
31
Complication of dental surgery causing apparent blindness
- stretching of maxillary artery
32
What can you give for an aggressive dog that cannot be examined in consult?
- trazodone, melatonin & gabapentin night before
- repeat gaba next morning
- can squirt ACP in mouth on arrival
33
What local block would you suggest for dog undergoing TECA?
- great auricular and auriculotemporal nerve
34
Dog scheduled for thoracic and abdominal imaging and bilateral anal sacculectomy in morning. What is most appropriate overnight tx?
- mild diuresis with 0.9% NaCl
35
Lab has vomiting and diarrhoea for several days. Decide he needs ex-lap. What fluid in perioperative period?
- Lactated ringers
36
What local block would you perform for upper canine removal due to abscess?
- caudal maxillary block
37
What volume of LA solution is recommended for caudal maxillary block?
- 0.03 - 0.05 ml/kg
38
Why is pressure applied by thumb when infraorbital block performed important?
- prevents needle from entering orbit
