2. Pre-Anaesthetic Assessment

Question 1

What are the basic principles of ensuring ‘safe’ anaesthesia?

Answer 1

• Appropriate restraint/handling
• Health check and BCS
• Withholding Food/water
• Analgesia
• Fluids
• Premedication
• Induction
• Maintenance
• RECOVERY

Question 2

What anatomical differences can cause additional risks to anaesthetic?

Answer 2

• Obligate nasal breathers (cats/horses/rabbits/rodents)
• Difficult to intubate (guinea pigs/rabbits)
• Lack of diaphragm (birds/reptiles)
• Pharyngeal tissue obstruction (guinea pigs)
• Small diameter blood vessels making it difficult to place a catheter

Question 3

What are the morbidity rates of animals under anaesthetic?

Answer 3

Dogs: 0.11% - 1.5%

Cats: 0.06%- 1.08%

Rabbits: 1.39%

Ferrets: 0.33%

Horses: 0.12% - 1.6%

Question 4

What is the ASA?

Answer 4

American scheme anaesthesia.

An animal is assessed and given a number from 1-5 or E.
1 - normal, no disease
2- mild systemic disease that does not limit normal function
3- severe systemic disease that limits normal function
4- severe systemic disease which is a constant threat to life
5- not expected to live 24hrs without surgery
E - emergency

Question 5

What is included in an initial patient assessment?

Answer 5

The animals history, signalment (name/age/species/sex/etc) and the reason for anaesthesia

Question 6

What do we need to consider when preparing for anaesthesia?

Answer 6

• Inform the owner of the procedure and risks- get consent!
• Withholding food and water (species dependant)
• Water deprivation
• Cleanliness of animal

Question 7

What is considered during a physical assessment?

Answer 7

• Elective or emergency case?
• BCS and weight
• Hydration status (CRT or skin tent can be used)
• Cardiovascular system- checking the heart and pulse rate (pulse deficits)
• Respiratory system- checking normal respiration rate or abnormalities during breathing
• GI/Integumentary/ Neurological system

Question 8

What are other anaesthetic considerations?

Answer 8

• Any clinical diagnosis
• Any diagnostic test results
• Recent trauma
• Species and breed considerations (brachycephalic)
• Any medication they are already on
• Disease status

Question 9

What anaesthetic considerations and ASA score would you give Bertie?

2yr old entire male Labrador. Friendly and well behaved coming in for an Orchidectomy.

Answer 9

• Owner informed consent
• History of the dog?
• Castration- minimal surgery time
• Withholding food 6-8hrs
• Withholding water 2-4hrs
• Handling/restraint- limit stress, labs are known for being quite boisterous
• Physical examination (TPR,CRT,weight,BCS) - Any clinical diagnosis
• ASA score = 1

Question 10

What anaesthetic considerations and ASA score would you give Roxy?

1yr old female Red rabbit. Healthy and coming in for an ovariohysterectomy.

Answer 10

• Restraint- limit stress
• Rabbits can overheat quickly with fatal results if temp exceeds 23-25 C
• Health check
• Consider lowgrade respiratory infections
• Obligate nasal breather
• Hypothermia due to high body surface ratio to volume
• Dehydration- rabbits have a larger fluid loss that cats or dogs
• Owner informed consent
• History
• Withholding food 30-60 mins
• ASA score = 1