ANAESTHESIA - Anaesthesia for Reproductive Surgery Flashcards
(52 cards)
Which should you advise owners before neutering surgery in regards to anaesthetic risk?
It is important to advise owners that there is always a risk of mortality with general anaesthetic, however it is low for neutering (1 in 10,000 in most recent studies)
Which factors should you consider before anaesthetising a patient for neutering?
Age
Breed
Temperament
Body condition score
Analgesia required
Health status
Although anaesthesia for neutering surgery is often viewed as routine it is always good practice to think about your patient as an individual and ask yourself if there are any factors that might affect the patient’s response to anaesthesia and that might therefore warrant a change in the anaesthetic plan
Which factors should you consider in regards to age before anaesthetising a patient for neutering?
It is mostly young adults that you are neutering, however be aware you may have to neuter older patients who will have an increased anaesthetic risk, or even very young patients (i.e. feral kittens) who will not yet be physiologically mature and thus have a higher anaesthetic risk
What are the steps of pre-anaesthetic preparation?
Fasting
Clinical examination
Pre-anaesthetic blood sampling (if appropriate)
Patients under 7 with no abnormalities on clinical exam don’t require bloods
Why is it so important to fast patients prior to general anaesthetic?
It is important to fast patients prior to general anaesthetic to reduce the risk of regurgitation and aspiration
How should you fast adult animals prior to general anaesthetic?
Traditionally adult animals are fasted overnight (minimum 8 - 12 hours), however you should allow for free access to water
How should you fast puppies and kittens prior to general anaesthetic?
If puppies or kittens are less than 8 weeks old, do not fast them for more than 2 hours, and allow for free access to water
What are the most common sedatives used in premedication for neutering surgery?
Medetomidine
Dexmedetomidine
Acepromazine
Pick most appropriate based on your individual patient
What are the most common opioids used in premedication for neutering surgery?
Methadone
Burpenorphine
Butorphanol
Pick most appropriate based on your individual patient
Which routes of administration are most commonly used for premedication for neutering surgery?
IM
IV
Pick most appropriate based on your individual patient
Which anaesthetic agents are most commonly used for induction for neutering?
Propofol
Alfaxalone
Pick most appropriate based on your individual patient
Which route of administration is used for induction for neutering?
Administer IV until the drug takes effect
Which inhaled anaesthetic agents are most commonly used for maintenance for neutering?
Isoflurane
Sevoflurane
Which factors should you consider when determining an anaesthetic plan for neutering an animal with an excitable/anxious temperament?
- Select a sedative dose at the higher end of the range
- Choose a more reliable sedative (i.e. α2 is more reliable than ACP)
- Combined sedation is also useful (e.g. ACP, metetomidine and methadone)
- IM for premedication may be preferable
Which factors should you consider when determining an anaesthetic plan for neutering an animal with an aggressive temperament?
- It can be useful to combine the sedative and opioid for the premedication with an injectible anaesthetic such as ketamine or alfaxalone (in cats)
- IM administration is preferable
e.g. metetomidine, methadone and low dose ketamine (get a strong sedation), or metetomidine, methadone and high dose ketamine (get an anaesthetic effect, used for cats only)
Which factors should you consider when determining an anaesthetic plan for neutering an animal at ASA grade II (i.e. older, less healthy animal)?
- Select a sedative dose at the lower end of the range (consider temperament)
- Select the most appropriate sedative considering the pharmacodynamics, side effects etc.
Which factors should you consider when determining an anaesthetic plan for neutering an animal at ASA grade III (i.e. systemically unwell animal)?
- Stabilisation
- Pre-anaesthetic blood testing
- Consider using an opioid only premedication
- Consider co-induction to reduce individual anaesthetic doses
- Aim for balanced anaesthesia
e.g. methadone premed, co-induction of propofol and alfaxalone, maintenance with iso or sevo
Use local anaesthetic technique ± infusion of fentanyl ± ketamine
What is balanced anaesthesia?
The use of a combination of drugs to achieve an anaesthetic effect, allowing for synergy and lower dose requirements for each drug
What are the three key components of multimodal analgesia used in neutering surgery?
Opioids
NSAIDs
Local anaesthetic
Which NSAIDs are licensed and safe for peri-operative use?
Meloxicam
Carprofen
Robenacoxib
Remember low blood pressure under anaesthesia can increase the risk of NSAID induced renal injury, so important to choose drugs that have been tested to be ‘safe’ under anaesthetic
When may you want to administer NSAIDs in more high risk patients?
You can withhold giving the NSAID until after anaesthesia and this might be preferred if there are other risk factors
What are the key differences between lidocaine and bupivicaine?
Lidocaine is licensed in dogs and cats, with a rapid onset and short duration of action. Bupivicaine is not licensed in cats and dogs, with a slow onset and long duration of action and is more cardiotoxic than lidocaine
What should you be aware of when administering local anaesthetic to cats?
Cats are more sensitive to the toxic effects of local anaesthetic and thus you should use lower doses and avoid intravenous route of administration
Which local anaesthetic blocks can you use in a castration?
Incisional block
Testicular block
