Premedication and Induction Flashcards
aims of premedication
sedation - handling
stress reduction
reduction in amount of anaesthetic agent used
analgesia
counter negative effect of anaesthetic agents
smooth recovery
alpha 2 agonists
xylazine, medetomidine
sedative and analgesic
negative feedback loop to pre synaptic vesicles - prevents norepinephrine release
reduced necessary dose of induction and maintenance agents
other effects -
blood pressure increase then decrease
HR decrease
increased urine production
vasoconstriction - reduces peripheral heat loss
antagonised - atipamezole
ACP
sedative only
given with an opioid for analgesia
leave 30-40 mins after admin
adrenoreceptor agonist
other effects -
vasodilation - fall in blood pressure and heat loss (avoid in animals with CV disease or in shock)
anti-arrythmic properties
anti emetic
not reversible
contraindicated in breeding stallions
benzodiazepines
midazolam, diazepam
minimal sedation - combined with ketamine
other effects -
minor CVRS suppression
manages convulsions
aims of induction
rapid action
smooth action
conveinience
consistent effects
good recovery
propofol
most common
rapid onset
short period of unconcsiousness
smooth emergence
other effects -
respiratory depression
CV depression
rigidity
heinz body aenmia
apnoea
can be used for top ups or TIVA
Thiopentone
very short acting
topping up in horses
prologed recovery in sight hounds
skin sloughing if injected outside vein
Alfaxalone
steroid anaesthetic
works on GABA receptor
clears body quickly
repeated bolus or TIVA
good CV stability, no histamine release, good muscle relaxation
ketamine
dissociative
induction and good analgesia
muscle rigidity - needs to be combined with something to relax
may be agitated during recovery
increased intracranial pressure
increased salivation and lacrimation
may have CVS effects dependent on dose
vomiting common when combined with alpha 2s - avoid in GI patients
depth assessment of eyes - up and open, starey
