MOD 20 - COURSE 3 - PT 1 - PREPARING FOR ANAESTHESIA Flashcards
WHAT ARE THE MAIN CONSIDERATIONS when preparing for anaesthesia
- selection of methods
- acclimatisation
- health check
- premedication
- fastign
when selecting a method for anasehtesia what consdierations need to be taken into account
- species
- age
- strain
- septh
- duration
- history
- pharamcological interference with experiment
- terminal anaesthesia… or repeates
= welfare coditions
how long do aniamls need to acllimitise after transport
- at least 7 days
- normally 14
why do they need acclimitisation after transport
- metabolic and hormonal changes return to normal
- so they cna be monitored for general health
- so aniaml staff can familiarise themselves with ebhaviour and characterisitcs of aniamsl, body weight, growth rate, food intake and water intake (recorded) - for pain assessment scale
why is it imporant anaiamls are carefully evaulated for health checks before anaesthesia ievent if on the surface they look fine
- they compensate for disease regularly
how will thin and ta aniamls differ for ananesthesia rates
- thin anamal= react very quickly - become overdose
- fat aniamsl = slow to respond
what is always included in health chekc
- body weight
- body conditions
- skin conditions
- signs of diarrhoea
- body temp
- discharge from eyes or nose
what are the advabtages of usig pre-medication as part of anaesthesia routine
- reduce aggression and fear suring induction of anaesthesia
- reduce pain in immediate post op period
- reduce anaesthesic dose required
- avoid problems during anaesthesia by reducign secretions or ptoexting the ehart from vagal inhibition caused in some procedures
what are the 3 major pranaesthetic drug groups
- anticholinergics
- tranqs and sedatives
- anaglesics
what examples of anti-cholinergics are there as pre-anaesthesia
- atropine or glycopyrrolate
why are anticholinergics used
- large species normally used - parasympatholytic actions
- seduce bronchial and salivary secretions - that could occlude airways
- prevent vagus nerve inhibition of the heart which can occur during endotracheal intubation or during surgical procedures - particulary if the visceral = handled
- not normally used in rodents
what are some negatives of using atropine
- atropine = preanaestheic anticholinergic
- increase HR
- IN ruminants (farm) atropine - doesnt completely block salivary secretions - become more viscous
- atropine = rapidly metabolised - in some strains of rabbits - so effects can be unpredictable in species
what are some undersirable effects of glycopyrrolate
- increases HR - although less pronounced than atropine
- glycopyrrolate = longer duration of action than atropine and has been reported to be most effective agent in rodents and rabbits
what are some exampels of tranqs and sedatives
- diazepam
- droperidol
- acepromazine
what is the purpose of tranqs and sedatives
- produce calming effects with/without sedation dependeing on agent
what are some advantages of tranqs and sedatives
- reduce fear and apprehensions in aniamls
- msucle relaxant and anti-convulsant activity - i.e. diazepam use din combination with ketamiene - counterwact muscle rigditiy induced by ketamine
- reduce total dose needed of anaeshtetics - i.e. ketamine ir ketamine + xylazine
- do not provide anaglesioa - reduce the aniamsl reaction to ahndling or pain via sedation and CNS depressions
why would you use anaglesics alongisde anaeshtetics as a pre-anaestheic
- reduce the nesscasryy dose of anaeshtic needed and may reduce post op pain
what is examples of anaglesics used as pre-anaesthetic
- opiods, fentanyl - effective against visceral pain
- loads of commercial prep combined potent analgeiscs and sedatives i.e :
- ## hypnorm (fentanyl and fluanisone)
when is fasting not required for pre anaesthesia
- if vomiting doesnt occur
if the animal doesnt vomit when does fasting still need to occur in those aniamsl - before anaesthesia
- if GI tract surgery - reduction in volume of gut contents
fasting = still kept to minimum
to clear the buccal cavitity adn oesophagus of small rodents - how long do they need to not eat for
- 1 hour before surgery - ensure no airway obstruction
how long to guinea pigs need to fast fo
3-4 hours - may retain food in pharaynx
hw logndo larger aniamls need to fast fo
- 8-12 hours - minimise risk of vomit
- ruminants - 3-4 days
- short period - 24 hours may reduce indicence of ruminal tympany or bloat
