Anesthesia Rounds 5

Question 1

GA risk for healthy dogs

Answer 1

0.05%

Question 2

GA risk for healthy cat

Answer 2

0.11%

Question 3

GA risk for healthy rabbit

Answer 3

0.73%

Question 4

GA risk for unhealthy dogs, cats, and rabbits

Answer 4

In unhealthy dogs the risks were 1.33 % (1/75 animals); cats 1.4% (1/71 animals); and 7.37% (1/14 rabbits).

Question 5

overall mortality under GA rates for dogs and cats

Answer 5

The overall mortality rate in dogs in the current/recent reviews is 0.17% (approx. 1/580 dogs anesthetized). The overall mortality rate in cats in the current/recent reviews is 0.24% (approx. 1/415 cats anesthetized).

Question 6

What in Zenalpha? what is it for?

Answer 6

Medetomidine 0.5 mg/ml
Vatinoxan – 10 mg/ml
* 1:20 ratio
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- This drug is not to be given as a pre-anesthetic
- An IM sedative agent

Question 7

Vatinoxan - what type of drug?
given this, what is the idea behind zenalpha?

Answer 7

• peripheral alpha2-antagonist
• Goal with this mixture is to reduce the initial hypertension and intensity and duration of the bradycardia/bradyarrhythmias
• The vatinoxan makes the effects of the medetomidine different

Question 8

Zenalpha time to sedation, duration, reversal

Answer 8

• Sedation noted in 3-5 minutes
• Average duration 35 minutes
• Reversal with atipamezole possible

Question 9

alpha-2 agonists central effects

Answer 9

• produce sedation centrally
  > presynaptic alpha2-adrenoreceptor reduces release of epinephrine and norepinephrine

Question 10

alpha2-agonists peripheral BP effects

Answer 10

Biphasic blood pressure response, IV > IM
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Pre-synaptic alpha2
- reduce NE, resulting in decrease BP
> low doses used in people
> effect in people predominates
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Post-synaptic alpha1 and alpha2
- causes contraction
- effect prodominates at doses used in veterinary medicine

Question 11

Specific Drug Effects of zenalpha

Answer 11

• Less baroreceptor mediated bradycardia but still central effects
• HigherHR
• Minimal hypertentsion
• Greater reduction in temperature
  > Footpad temperature increase

Question 12

What do the effects look like for zenalpha?

Answer 12

• Sedation is rapid and deep but of shorter duration than with MED or DEXMED
• Vatinoxan does not completely eliminate the bradycardia
  > Still have the centrally mediated bradycardia
• Heart rate will be lower than baseline for 5-10 minutes but then starts to rebound and will maintain at a higher level than MED alone

Question 13

who should we not use zenalpha with?

Answer 13

• Cats respond differently
• Felines do not have the intense vasoconstriction that dogs and horses do with medetomidine and dexmedetomidine
• This product results in > reduction in BP in cats at 1:20 ratio
  > Likely different formulation in cats in the future