Anaesthesia Flashcards
What do AA, AB , AC or AD stand for during anaesthesia?
AA- no anaesthesia
AB- anaesthesia with recovery
AC - anaesthesia no recovery
AD - neuromuscular agents used - with an anaesthetic agent)
How is reuse of animals looked upon by home office?
Strongly discouraged - will say if they are able to be resused - due to long lasting distress ..
What affects are within the triad of anaesthesia?
- loss of consciousness
- Muscle relaxation
- loss of sensation
What topical local anaesthetic may be useful on animals?
Anaesthetic cream - EMLA, Astra - prevent pain associated with venepuncture
What other systems apart from the brain and SC, will be affected by anaesthetic?
- cardiovascular effects - hard rate reduces
- respiratory depression - reduced breathing frequency (often breathe deeper)
- BP falls
- Animal becomes cold/loses heat
What animals need to be fasted before anaesthesia and why?
- dogs, cats, non-human primates, ferrets, pigs, maybe sheep
- Need to be fasted as anaesthesia may cause nausea - - may cause vommitting during anaesthesia- risk of being inhaled into lungs - pneumonia
What animals do you not withold food from (fast), before anaesthetic?
rodents, rabbits, guinea pigs
How many days do animals need to become acclimatised to new surroundings before undergoing anaesthesia?
7-10 days to get used to new surroundings
What condition of the animal needs to be checked before anaesthesia?
Animal needs to be checked that it is in good health for recovery anaesthetic.
- animals should be weighed regularly to monitor for changes in weight
Give some examples of local anaesthetics
- topical anaesthetics - EMLA cream
- lidocaine injection
- block nerve chunks by epidural or intrathecally (CSF)
Give some advantages of inhalational anaesthetic
- simple to administer
- induction is smooth and rapid
- easy to change depth
- recovery is rapid and uneventful
- can anaethetise multiple animals at one time but will need multiple mouth pumps to maintain state
Give some advantages of injectable anaesthetics
- multiple animals anaesthetised at once
- does not require specialist equipment
Give disadvantages of injectable anaesthetics
- need to be able to deliver oxygen
- dose cannot be adjusted when administered
- individual variability to dose
- intravenous injection may be technically difficult
- some specialist training required to know what site to inject into
Give some disadvantages of inhalational anaesthetics
- expensive equipment
- waste gases need to be removed
- depending on equipment may only be able to anaesthetise one animal at a time
Give some signs of ill health in a mouse
- ruffled/dirty coat
- closed/sqinting eyes
- hunched over
- not as active or alert
- lose weight
- abdominal twiching
- pale feet/nose/ears/tail
- puffed out cheeks
- scrunched face
What are the 4 routes of administration of injectable anaesthetic
- intraperitoneal (IP)
- intravenous (IV)
- intramuscular (IM)
- subcutaneous (SC)
give some examples of injectable anaesthesia
- ketamine (combined with sedative/analgesic) e.g. medetomidine
- alphaxalone
- Hypnorm (with midazolam or diazepam)
- etomidate (With fentanyl)
- propofol
- pentobarbital
Is it a good idea to administer ketamine via IM injection?
No - can be irritant and may cause muscle damage
how long does it usually take to recover from injectable general anaesthetic?
60-180 mins
IV usually shorter - 20-30 mins
How can recovery from anaesthesia be sped up?
- warm animal up
- administer antagonist
What is the antagonist to ketamine/medetomidine?
atipamezole
How do you check animal is suitably anaethetised before anaesthetic?
- check withdrawel reflexes
- check eye position/reflex
- ear pinch (in rabbits and guinea pigs only)
What two withdrawel reflexes are used in rodents?
- Tail pinch (lost first - light anaethesia)
- pedal/toe pinch - medium/deep plains of anaestheisa - state of surgical anaesthesia
What is normal resp rate and heart rate of mouse?
- resp rate - 60-100 -(i think more (60-200) per min
- HR - 300-800 bpm
What is the normal body temperature of a mouse?
38-39 C
How can we prevent eye injury during anaesthesia?
keep eyes moist
- opthalmic ointment
- tape eyes closed
What resp stimulant can be use don mice who stop breathing?
Doxapram - 10mg/kg
How far does body temp have to fall to be defined as hypothermia in mice?
- fall of 2 c
What can we do to reduce heat loss from mice during anaesthesia?
- keep on warm blanket
- wrap in bubblewrap / foil
- warm fluids up before administering
- air warming blankets
Give some examples of inhalational anaesthetics
- sevoflourane
- halothane (no longer available)
- enflurane
- desflurane
- methoxlyflurane (no longer available )
- isoflurane
- ether (do not use)
What should the percentages of isoflurane or sevoflurane be in an anaethetic chamber and what should the flow rate be?
- isoflurane 5%
- sevoflurane (8%)
- 4 litres per min flow rate (in 2 litre chamber)
What is the tidal volume of a mice?
7-10ml/kg
what NSAID may be appropriate for post-operative pain?
carprofen
When should the anaesthetic aim to be filled by?
In less than a minute - aim to induce full anaesthesia quickly - reduce period of excitement
What dose of ketamine/medetomidine is recommended for use in mice?
75mg.kg
What dose of ketamine/xylazine is recommended for use in mice?
80-100mg/kg
How much respiratory depression is allowed before alarm?
- is animal loses more than 40% of the expected/standard breathing rate - become alarmed
