Pre-ana Fasting

Question 1

What makes anaesthetic risky for species that eat prior to anaesthesia?

Answer 1

• Vomiting, as anaesthetised animals lack the ability to swallow
• Meaning
• Vomit or regurgitation may be inhaled into the airways
• > >
• Respiratory Arrest
• Aspiration Pneumonia

Question 2

If a patient hasn’t been fastened prior to surgery or anaesthesia, what are 2 suitable options?

Answer 2

• VS prescribes Antiemetic drugs, to empty stomach
• Post-pone the surgery

Question 3

True or False.

You must remove water prior to anaesthesia in all patients.

Answer 3

False.

As this will lead to dehydration
»
Further issues

Until pre-med has been prescribed, where it should be removed

Question 4

Why are diabetic patients the exception to pre-anaesthetic fastening?

Answer 4

• As most diabetics require shorter fastening periods
• Due to the need to eat at specific times
• For insulin injections

Question 5

Why might evidence suggest that extensive fasting times become more detrimental?

Answer 5

Increased fastening times
>
Increase incidence of Gastro-Oesophageal Reflux (GOR)

Question 6

Gastro-Oesophageal Reflux

Why does GOR occur, during anaesthesia?

Answer 6

• Reduction in lower Oesophageal Sphincter Pressure
• Leading to: Inflammation > Stricture > Death

Question 7

True or False.

Unweaned Puppies + Kittens can be fastened prior to anaesthesia, if done carefully.

Answer 7

False.

• They must never be fasted
• As they have an increased risk + incidence of regurgitation

Question 8

Why do unweaned Puppies + Kittens have a higher risk of regurgitation?

Answer 8

Because they have an underdeveloped Lower Oesophageal Sphincter Tone

Question 9

When does the Lower Oesophageal Spincter Tone in Puppies + Kittens, mature?

Answer 9

At 5 weeks old

Question 10

LOST = Lower Oesophageal Sphincter Tone

What is another factor that increases the risks of anaesthesia for Puppies + Kittens, despite their underdeveloped LOST?

Answer 10

• Their glycogen stores are low
• Depletion can result in Hypoglycaemia

Question 11

If an unweaned Puppy or Kitten must undergo surgery, if absloutely necessary, what can be done?

Answer 11

• Suckling patients must not be fastened
• If GI track is involved etc, then at the absloute necessity + with great risk, they must be fastened, no longer than 2 hrs max

Question 12

What is the danger of prolonged fasting?

Answer 12

• Hypoglycaemia, leading to >
• Dehydration, leading to >
• Hypothermia

Question 13

If Hypoglycaemia occurs in a puppy or kitten, what should be done to rectify it?

Answer 13

1. Establish Normoglycaemia
2. Provide IV Glucose

Question 14

Apart from neonates or unweaned puppies and kittens, what other class of patients shouldn’t be fastened for too long?

Answer 14

Geriatrics

Question 15

Give 5 reasons why Geriatrics are at risk, during anaesthetic fastening?

Answer 15

They are at greater risk of:
1. Dehydration
1. Low Glycogen reserves in the Liver (»_space; Hypoglycaemia)

Reduced:
2. Oseophageal motility
3. Gastric acid secretion
4. Delayed gastric emptying time..

Question 16

What makes Geriatrics more prone to Aspiration Pneumonia, during the Induction + Post-op period?

Answer 16

Their delayed gastric emptying time

Question 17

List 4 ways to prevent Aspiration in Geriatrics or any other patient?

Answer 17

1. Use of Gastric Protectants
2. Appropriate fasting intervals
3. Ensure secure airway
4. Suction oesophagus prior to extubation

Question 18

What class of species doesn’t require anaesthetic fasting?

Answer 18

1. Mostly Herbivores
2. Some Rodents
3. Avians

Question 19

Why shouldn’t Herbivores be fastened prior to anaesthetic?

Answer 19

They cannot vomit, due to their strong Oesophageal sphincters

• As they lack:
  1. Neurological circuits
  1. Muscular structure
• Have:
  1. Less muscular diaphragms
  1. Longer Oesophagi

Question 20

True or False.

You should never restrict water from Herbivores prior to anaesthetic.

Answer 20

True

Question 21

What 6 factors depend on anaesthetic fasting?

Answer 21

1. Species
2. Size
3. Age
4. Health
5. Feeding habits
6. Procedure to be performed

Question 22

Why is fasting important in all species, especially in reptiles?

Answer 22

Reduce the risk of:
1. Regurgitation
1. Lung compression

Question 23

(Hint = anaesthetic fasting)

How may a patient get lung compression during anaesthetic?

Answer 23

• Large meals will compress the lungs
• So fasting will promote good ventilation

Question 24

5…

What can the incidence of Gastro-Oesophageal Reflux contribute towards?

Answer 24

1. Morbidity
2. Mortality
3. Aspiration Pneumonia
4. Oseophagitis
5. Oesophageal Stricture Formation