Injectable Anesthesia

Question 1

drug kinetics and dynamics

Answer 1

• anesthetics are generally:
  
  • very liposoluble
  • highly protein bound
  • reach the brain rapidly
  • redistributed to other tissue
    
    • muscle
  • accumulation in fat

Question 2

propofol

Answer 2

• alkylphenol compound
• insoluble in water
• egg lecithin
  
  • contamination
  • 6 hours opened
• shelf life 3 years
• no problem if given perivascular

Question 3

important effects of propofol

Answer 3

• decrease in BP, CO, and SVR
  
  • short cardiac depression
• fast acting, short half-life
• excitation (fast bolus)
  
  • 1st inhibit inhibitory = excitation
• apnea, respiratory depression
• may protect CNS
  
  • decrease ICP and CMR, but decrease CPP
• “seizure-like activity”

Question 4

MOA of propofol

Answer 4

• action in GABA receptors
• increase influx of chloride
• hyperpolarization
• anesthesia for 10-15 minutes after induction dose
  
  • redistribution

Question 5

ketamine

Answer 5

• cyclohexamine
• dissociation between thalamus and limbic system
• hepatic metabolism in dogs and horses
• portion eliminated unchanged by cats!!
  
  • ​avoid in HCM and RF cats
• large therapeutic index
• can be given IM
• increase sympathetic tone

Question 6

CV effects of ketamine

Answer 6

• sympathetic stimulation
• increase HR and BP
  
  • not good for HCM
• direct myocardial depressant (don’t see this usually)

Question 7

respiratory effects of ketamine

Answer 7

• apneustic breathing
• apnea
• maintained laryngeal reflexes and PaO2

Question 8

neurologic effects of ketamine

Answer 8

• increase in ICP, CBF, IOP, decrease seizure threshold
• somatic analgesia
• excitement at emergence
  
  • motor activity
  • sensitivity to touch
  • violent recovery

Question 9

clinical effects of ketamine

Answer 9

• increase salivation and mucus (don’t use atropine)
• poor muscle relaxation (combine w/ benzo)
• reflexes are maintained (don’t use des)
• rough recoveries
• often combined with benzos

Question 10

telazol

Answer 10

• same sites of action as ket/val
• 1:1 combination
  
  • tiletamine
  • zolazepam
• lyophilized powder
  
  • reconstituted with sterile water
• smaller volume
• rough recoveries without premeds
• can be reconstituted with ketamine and alpha2

Question 11

CV and respiratory effects of telazol

Answer 11

• CV
  
  • similar to ketamine
  • increase HR, BP and SVR due to sympathetic stimulation
• Respiratory
  
  • similar to ketamine

Question 12

neurologic effects of telazol

Answer 12

• maintained reflexes
  
  • coughing
  • swallowing
  • corneal reflexes

Question 13

etomidate

Answer 13

• acts on GABA A receptors
• propylene glycol based, imidazole derivative
• hemolysis
• combined with opioid or benzo for induction
• expensive
• minimal CV effects-good for cardiac patients
• poor muscle relaxant
• adrenal suppression (addisonian crisis)

Question 14

CV and respiratory effects of etomidate

Answer 14

• CV and respiratory stability

Question 15

neurologic effects of etomidate

Answer 15

• CNS friendly
• myoclonus
• poor muscle relaxation
• usually combined with benzo or opioids

Question 16

alfaxalone

Answer 16

• neurosteroid in Ciclodextrin
• act in GABA
• can be given IM
• minimal CV effects
• good for premed of difficult cats

Question 17

Cardiorespiratory effects of alfaxalone

Answer 17

• minimal CV effects
  
  • increase HR and CO
  • decrease BP (vasodilation)
• dose dependent respiratory depression
  
  • apnea after bolus

Question 18

neurologic effects of alfaxalone

Answer 18

• CNS friendly
• excitation in cats during recovery (IM route)

Question 19

opioids

Answer 19

• fentanyl, hydromorphone bolus
• narcosis not anesthesia
• CV friendly, no myocardial depression
  
  • ​use in sick patients/CV compromised
• decrease HR, respiratory depression
• analgesia
• reversible
• short acting (fentanyl)