Fifth Year Anaesthesia Revision Flashcards
(31 cards)
How does lidocaine work?
Blocks voltage-gated sodium channels → prevents nerve depolarisation → local anaesthesia.
What are the clinical effects of lidocaine?
Local anaesthesia
Anti-arrhythmic (Class 1b)
Mild analgesia.
What are the side effects of lidocaine?
CNS signs (tremors, seizures), hypotension, bradycardia, cardiovascular depression (at high doses).
How can lidocaine toxicity be mitigated?
Use appropriate dosing (esp. in cats), avoid IV bolus in cats, calculate carefully.
How does ketamine work?
NMDA receptor antagonist → dissociative anaesthesia and analgesia.
What are the clinical effects of ketamine?
Catalepsy, increased muscle tone, increased heart rate and blood pressure, analgesia.
What are the side effects of ketamine?
And how can these be mitigated?
Muscle rigidity, salivation, emergence delirium, increased ICP/IOP.
Combine with benzodiazepines or alpha-2 agonists for muscle relaxation and smoother recovery.
How does propofol work?
GABA-A receptor agonist → CNS depression.
What are the clinical effects of propofol?
Rapid induction and recovery, anti-convulsant, minimal analgesia.
What are the side effects of propofol?
And how can these be mitigated?
Apnoea, hypotension, bradycardia, Heinz body anaemia in cats with repeated use.
Administer slowly IV to effect, pre-oxygenate, monitor BP and respiration.
How does medetomidine work?
Alpha-2 adrenergic agonist → decreases noradrenaline release → sedation, analgesia, muscle relaxation.
What are the clinical effects of medetomidine?
Profound sedation and analgesia, vasoconstriction followed by bradycardia.
What are the side effects of medetomidine?
And how can these be mitigated?
Bradycardia, AV block, reduced CO, vomiting, hypothermia.
Do not treat reflex bradycardia with atropine unless pre-treated with an anticholinergic; reverse with atipamezole if needed.
How does methadone work?
Full mu-opioid receptor agonist; also NMDA antagonist.
What are the clinical effects of methadone?
Strong analgesia, mild sedation, useful for visceral pain.
What are the side effects of methadone?
And how can these be mitigated?
Respiratory depression, bradycardia, panting, vomiting (less than morphine).
Monitor ventilation, reverse with naloxone if needed.
How does atipamexole work?
Alpha-2 adrenergic antagonist → reverses sedation and bradycardia caused by alpha-2 agonists (e.g., medetomidine).
What are the clinical effects of atipamezole?
Rapid reversal of sedation and cardiovascular effects.
What is the dose of atipamezole for cats and dogs?
Cats = 1/2 medetomidine
Dogs = full dose of medetomidine
How does meloxicam work?
COX-2 preferential NSAID → reduces prostaglandin synthesis.
What are the effects of meloxicam?
Analgesia, anti-inflammatory, antipyretic.
What are the side effects of meloxicam?
How are these mitigated?
GI upset, renal compromise, hepatopathy with chronic use.
Avoid in dehydrated, hypotensive, or renally impaired animals; ensure appropriate hydration and perfusion.
How does isoflurane work?
Volatile anaesthetic → GABA-A receptor modulation, CNS depression.
What are the effects of isoflurane?
Reversible unconsciousness, dose-dependent CV and respiratory depression.
