Pre-ana Fasting Flashcards
What makes anaesthetic risky for species that eat prior to anaesthesia?
- Vomiting, as anaesthetised animals lack the ability to swallow
- Meaning
- Vomit or regurgitation may be inhaled into the airways
- > >
- Respiratory Arrest
- Aspiration Pneumonia
If a patient hasn’t been fastened prior to surgery or anaesthesia, what are 2 suitable options?
- VS prescribes Antiemetic drugs, to empty stomach
- Post-pone the surgery
True or False.
You must remove water prior to anaesthesia in all patients.
False.
As this will lead to dehydration
»
Further issues
Until pre-med has been prescribed, where it should be removed
Why are diabetic patients the exception to pre-anaesthetic fastening?
- As most diabetics require shorter fastening periods
- Due to the need to eat at specific times
- For insulin injections
Why might evidence suggest that extensive fasting times become more detrimental?
Increased fastening times
>
Increase incidence of Gastro-Oesophageal Reflux (GOR)
Gastro-Oesophageal Reflux
Why does GOR occur, during anaesthesia?
- Reduction in lower Oesophageal Sphincter Pressure
- Leading to: Inflammation > Stricture > Death
True or False.
Unweaned Puppies + Kittens can be fastened prior to anaesthesia, if done carefully.
False.
- They must never be fasted
- As they have an increased risk + incidence of regurgitation
Why do unweaned Puppies + Kittens have a higher risk of regurgitation?
Because they have an underdeveloped Lower Oesophageal Sphincter Tone
When does the Lower Oesophageal Spincter Tone in Puppies + Kittens, mature?
At 5 weeks old
LOST = Lower Oesophageal Sphincter Tone
What is another factor that increases the risks of anaesthesia for Puppies + Kittens, despite their underdeveloped LOST?
- Their glycogen stores are low
- Depletion can result in Hypoglycaemia
If an unweaned Puppy or Kitten must undergo surgery, if absloutely necessary, what can be done?
- 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
What is the danger of prolonged fasting?
- Hypoglycaemia, leading to >
- Dehydration, leading to >
- Hypothermia
If Hypoglycaemia occurs in a puppy or kitten, what should be done to rectify it?
- Establish Normoglycaemia
- Provide IV Glucose
Apart from neonates or unweaned puppies and kittens, what other class of patients shouldn’t be fastened for too long?
Geriatrics
Give 5 reasons why Geriatrics are at risk, during anaesthetic fastening?
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..
What makes Geriatrics more prone to Aspiration Pneumonia, during the Induction + Post-op period?
Their delayed gastric emptying time
List 4 ways to prevent Aspiration in Geriatrics or any other patient?
- Use of Gastric Protectants
- Appropriate fasting intervals
- Ensure secure airway
- Suction oesophagus prior to extubation
What class of species doesn’t require anaesthetic fasting?
- Mostly Herbivores
- Some Rodents
- Avians
Why shouldn’t Herbivores be fastened prior to anaesthetic?
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
True or False.
You should never restrict water from Herbivores prior to anaesthetic.
True
What 6 factors depend on anaesthetic fasting?
- Species
- Size
- Age
- Health
- Feeding habits
- Procedure to be performed
Why is fasting important in all species, especially in reptiles?
Reduce the risk of:
1. Regurgitation
1. Lung compression
(Hint = anaesthetic fasting)
How may a patient get lung compression during anaesthetic?
- Large meals will compress the lungs
- So fasting will promote good ventilation
5…
What can the incidence of Gastro-Oesophageal Reflux contribute towards?
- Morbidity
- Mortality
- Aspiration Pneumonia
- Oseophagitis
- Oesophageal Stricture Formation
