Anaesthesia of Rabbits, Rodents and Ferrets Flashcards
17.2.14
When do the majority of anaesthesia related deaths in rabbits occur?
Postoperatively
Which type of rodent has the highest risk of death? Why?
Guinea pig
Difference between MAC dose and respiratory arrest dose is very small.
Give an example of a predator and prey rodent species
Predator: Ferret
Prey: Rabbit
What are the most common reasons for anaesthesia in rabbits?
Dentals
Neutering
Traumatic injuries (inc. flystrike)
Diagnostic imaging
What animal should rabbits be thought of as..?
Tiny horses!
What are the most common anaesthetic problems in rabbits?
Post-operative ileus*
Difficultly intubating and ^risk of blockages
Obesity
*What are three things associated with post-op ileus? How can they be overcome?
Pain - provide good analgesia
Anorexia - aim for fast recovery
Stress - get rabbit home asap
What is the most common subclinical disease of rabbits?
Respiratory
- Pasteurellosis
(Rabbit snuffles)
§Assume all rabbits have respiratory dysfunction§
What is referred to as a “carpal handkerchief?”
Nasal discharge seen on medial aspects of the forelegs with rabbit snuffles
Why may dental problems in themselves cause an ^anaesthetic risk?
Has probably gone unnoticed for weeks -> malnourishment and dehydration on presentation
What five points should be checked during pre-aneastheitc examination of the rabbit?
- History ( esp. previous illness and previous anaesthesia)
- Check for visual signs of illness and dyspnoea
- Signs of respiratory disease
- normal clinical exam
- Check renal function if any signs of incontinence*
*What pathogen is associated with urinary incontinence in rabbits?
Encephalitozoon Cuniculi
Name 4 places blood samples may be taken from a rabbit.
Cephalic v.
Marginal ear v. §NOT CENTRAL OBVIOUS VESSEL IN EAR - THIS IS AN ARTERY!§
Lateral saphenous v.
Jugular v.
Why must care be taken when sampling from the ear of a rabbit?
Do NOT use large central vessel - this is the central ear ARTERY.
Should rabbits be starved pre-aneasthesia?
No - they don’t vomit. But do check mouth is clear.
How may dehydration be corrected in the rabbit?
Crystalloid fluid - up to 30-50ml sub cut
Up to 50mls intraperitoneally (Lower Right Quadrant)
IV (Rate depends on urgency)
When should an IV catheter be placed?
Pre-induction (potentially post-sedation)
What may be applied before catheterisation?
EMLA cream - apply~1hr pre venipuncture, occlude from air (cover in plaster/rubber gloves etc.)
What gauge catheter should be used for a rabbit? What colour is this?
22G (Blue) or
24G (Yellow)
What does EMLA stand for? What is it?
Eutectic Mixture of Local Anaesthetics
Lidocaine and Prilocaine
What drug is often used before catheterisation but does NOT actually work?
Intubeaze (designed for cats larynx intubation)
Does not work on skin!
Are pre-meds always given to rabbits?
No. Depends on technique and temperament.
What are the most common pre-meds for rabbits?
Hypnorm
Medetomidine (a2 ag)
Pre-emptive analgesia eg. butorphanol, buprenorphine, meloxicam
What other kind of induction (other than injectables) is possible? When is this used?
Mask induction
Should be AVOIDED at all costs
- causes breath holding and bradycardia -> hypoxeamia, hypercapnia and acidosis
- sevoflurane often advocated over isoflurane due to lack of smell, but this is not actually any better (mask placement causes diving reflex, not smell)
- may be possible if pre-med sedatives given.
What do all anaesthetic agents do to respiration?
Respiratory depression
What is hypnorm? How is it given? Licensed?
Induction agent - licensed
Fentanyl (Opiod) and Fluanisone (Azaparone) mixture (IM injectable)
What effects does hypnorm have?
Profound respiratory depression (opioid component) reversible using opioid ants.
Poor muscle relaxation (usually used in conjunction benzodiazepene eg. medazolam/diazepam)
Long recovery
Fentanyl induced ileum possible as in horses due to opioid.
How are ketamine combinations given? Licensed?
IM or SC - not licensed.
What ketamine combination gives best surgical conditions?
Ketamine/a2 ag/opioid
What drug may be used to reverse the effects of an a2 ag? Dose?
Atipamezole (a2 ant)
Dose = 5x medetomidine
What is the most profound negative effect of ketamine induction? How can this be rectified?
Hypoxeamiea
- give O2
What are the disadvantages of ketamine combination induction?
Variable effect Peripheral vasoconstriction - may hinder pulse ox - pale mucous membranes - difficult to find wins for blood samples