Anaesthesia for Dental, Ocular and Airway Surgery Flashcards
what range of procedures fall under dental surgery?
scale and polish to full resections and jaw repair
what is the main obstacle to anaesthetic monitoring with dental procedures?
access to mouth and face can be difficult
what is a significant risk associated with dental procedures?
aspiration and hypothermia
why are aspiration and hypothermia such a risk with dental surgery?
lots of water used
what types of patient are often having dental surgery?
geriatric
those with underlying conditions
what are the main anaesthetic considerations associated with dental surgery?
pain
haemorrhage
hypothermia
aspiration of water/fluids
procedure could be very long
concurrent disease
is dental scaling alongside other surgical procedures recommended?
no
what are the anaesthetic considerations for geriatric patients?
reduced functional residual capacity
reduced cardiovascular reserve
reduced muscle mass
increased fat tissue
prone to hypothermia
may have reduced liver and kidney function
what is the effect of reduced cardiovascular reserve in geriatric patients?
baroreceptor function reduced so more prone to hypotension
less tolerant of tachycardia as max HR is lower
what is the effect of reduced functional residual capacity in geriatric patients?
more prone to hypoxia
what is functional residual capacity?
volume remaining in the lungs after a normal, passive exhalation
what is the effect of reduced liver and kidney function in geriatric patients?
reduced drug metabolism
longer duration of action
exacerbated drug effects
what tests may be carried out on a patient pre-op?
blood and urine testing
US
ECG
X ray
full clinical exam
assessment of other disease processes
what is commonly seen in cats with dental disease?
anorexia
why may preoperative fluid be needed for geriatric patients?
support for kidneys to prevent reduction in GFR and further damage
why must hypotension be avoided in patients with underlying kidney disease?
reduced GFR can exacerbate kidney problems
what medication may dental patients be on already?
NSAIDs
antibiotics
what must be considered when picking a breathing system for dental surgery?
no mcgill (eww)
what are the intraoperative considerations for dental surgery?
analgesia
manage airway
hypothermia is significant risk
eye care (human and patient!)
what additional analgesia can be considered for dental procedures?
local block
why is MAC sparing important especially for geriatric patients?
VA have significant vasodilatory effect and so lead to hypotension - need to avoid in geriatric patients
what type of ET tube must be used in dental surgery and why?
cuffed due to high risk of aspiration
what must be placed in the mouth prior to dental surgery commencing?
mouth pack (may need to change if surgery is long)
what is involved in ET tube management during a dental?
ensure no kinking or twisting
care when turning the patient
what are the main concerns if a dental procedure is running long?
hypothermia
patient may be wet
require sedation top up
what type of mouth gaga must be avoided in cats?
spring loaded
why must spring loaded mouth gags be avoided in cats?
can cause damage to facial nerves and could lead to blindness
define MAC
minimum concentration of vapour in the alveoli that is needed to prevent motor response in 50% of subjects in response to surgical stimulus
is haemorrhage a concern in dental surgery?
yes - mouths can bleed a lot, also may be difficult to calculate with the volume of water in use
what are the main positioning concerns during dental surgery?
will be in the same position for a while
joints should be padded
sores avoided
watch for atelectasis
what is atelectasis?
complete or partial collapse of the entire lung or lobe of the lung
when can atelectasis occur?
if the lung becomes deflated (patient in one lateral for too long) or filled with alveolar fluid
what can be considered if the dental procedure is taking too long?
staging - ensure owner is aware on admit that this may happen
why are local blocks for dental so useful?
dentals are very painful
MAC sparing
improved post op pain management
improved speed of recovery and return to eating
how long may local blocks provide post op pain management?
up to 6 hours
what should owners be made aware of if local blocks are to be used?
may be clipped patches on patients face
can RVNs perform dental blocks?
yes
what are the main dental blocks used?
rostral maxillary (infraorbital)
caudal maxillary
caudal mandibular
mental
what is blocked by a rostral maxillary (infraorbital) nerve block?
soft tissues, incisors, canine and premolar teeth
where is the infraorbital foramen located in dogs?
on the maxilla, dorsal to third maxillary premolar
why should care be taken when performing a rostral maxillary (infraorbital) block in cats and brachycephalic dogs?
foramen is located at the level of the medial canthus of the eye so care must be taken when injecting
what is the preferred maxillary block?
caudal maxillary
what is blocked by a caudal maxillary nerve block?
all bones of maxilla, soft and hard palates, soft tissues of the nose, upper lip, dentition rostral to maxillary second molar
where is the foramen located for a caudal maxillary block?
needle is inserted caudal and centrally behind the last maxillary molar
what is blocked by a mandibular nerve block?
entire hemimandible teeth of the lower jaw
where is the foramen for the mandibular nerve block located?
needle inserted percutaneously at the ventral angle of the mandible
why may bilateral mandibular nerve blocks be discouraged?
loss of sensation to tongue can affect ability to swallow
risk of damage to self due to lack of sensation during recovery
is a mental nerve block commonly seen?
no
what is blocked by a mental nerve block?
lower incisors, skin and tissues rostral to foramen
how easy is the foramen for a mental nerve block to find?
tough in small animals
easy to palpate in large animal
what type of mandibular block may be preferred in smaller animals?
mandibular
what equipment is needed for local block placement?
sterile needle and syringe
local agent
scrub
alcohol wipe/liquid
sterile gloves
what must be calculated prior to local block placement?
maximum patient dose
what must be considered when calculating maximum LA dose?
intubeaze
how much lidocaine is contained in one spray of intubeaze?
2.27mg in 0.14ml
what are the considerations post dental GA?
pain score and provide analgesia
keep warm
dry and clean patient
remove mouth pack and gag
TTE
IVFT if needed
thorough discharge to owners
what are the reasons for occular surgery?
cataracts
enucleation
eyelid mass removal
entropion
cherry eye
trauma
what are the pre op considerations for occular surgery?
pain
risk of eye rupture
underlying disease presence
specific medications the patient may be on
procedure to be performed
what medications may an ocular patient be on that must be considered/recorded?
NSAIDs
steroids
what may be done before ocular surgery?
bloods
clinical exam
history
pre-operative screening
what should be used to prep the eye?
iodine NOT hibi
what must be prevented from occuring pre or during eye surgery?
further eye trauma
how can further trauma to the eye be prevented under GA?
eye lube
care with masks
care with bear hugger
careful prep
what additional drugs may be needed for certain ocular procedures?
NMBA for central eye
why may NMBAs be useful for ocular procedures?
maintain a central eye
what is normal intraocular pressure?
15-20 mmHg