Clinical pharmacology of anaesthetics Flashcards
Mechanism of propafol
Stimulates GABA
Propofol has higher metabolism in cats
False!
In what situations should I be careful when giving propofol
Shocked / hypovolaemic patients
Cats with hepatic dysfunction
Cats requiring repeat anaesthetics
Difference and similarity between Alfaxalone and Propofol
Propofol is given IV Alfax is given IV/SC/IM
Propofol’s structure is a hindered phenol while Alfax is a steroid
They both stimulate GABA
Typically should I use alfaxalone or propofol in cats? Why
Use alfaxalone. Propofol can cause heinz body anaemia
Mechanism of Ketamine
NMDA receptor antagonist
Ketamine is a dissociative anaesthetic. What features differentiate them from non dissociative anaesthetics
Sensory loss with analgesia
Increased muscle tone
Eyes open ± slow nystagmus
Active reflexes incl. laryngeal/pharyngeal reflexes
Less profound CVS & respiratory depression
What are some clinical uses of ketamine
To induce anaesthesia in dogs, cats & horses
- Combined with a benzodiazepine & injected IV
To induce & maintain anaesthesia (~ 30 min) in dogs & cats
- Combined with an a2-agonist and butorphanol & injected IM (“triple combo”)
To provide analgesia in dogs & cats
-Much lower doses given IM, SC or by IV infusion
Ketamine should be given with caution esp with patients that?
A history of seizures
Elevated intracranial pressure
Pre-existing tachycardia
What is Total Intravenous anaesthesia (TIVA)
intravenous anaesthetics to both induce & maintain anaesthesia
When would I use total intravenous anaesthesia
Where inhalational anaesthetic agents not available
Where the airway cannot be shared
What is Minimum Alveolar Concentration (MAC)
MAC is the steady-state minimum alveolar concentration of anaesthetic required to prevent gross purposeful movement in response to noxious stimulation, in 50% of test subjects
MAC allows comparison of the potency of different inhaled anaesthetics
