Anesthesia and Euthanasia

Question 1

What are the three methods of anesthesia used? What is the difference between them?

Answer 1

general - loss of consciousness and loss of sensation
local - loss of sensation (pain or otherwise) in a limited body area
regional - loss of sensation of a larger area (nerve blocks, spinal anesthesia)

Question 2

What are the factors that affect anestehsia?

Answer 2

differing metabolic rates, hepatic microsomal enzyme activity, build up of tolerance, interaction with other drugs

Question 3

what are factors that change metabolic rates? Describe how they affect BMR.

Answer 3

size - small have higher BMR
age - neonates have low BMR
sex/gender - male and pregnant higher
recent feeding - increase
fear - increase
tranquilizers - decrease
concurrent disease - usually decrease but fever and hyperthyroidism increases

Question 4

what are methods of anesthetic delivery?

Answer 4

dermal/topical, injectable (IM, IV, IP, SC), inhalant

Question 5

Describe how two body systems get affected “anesthetic emergencies”.

Answer 5

cardiac - cardiac arrest, arrhythmia, bradycardia

respiratory - dyspnea, respiratory arrest

Question 6

What are the stages of anesthesia and the appropriate plane of anesthesia?

Answer 6

1. rising pain threshold
2. excitement phase
3. surgical anesthesia (plane 3 - no reflexes, shallow breathing)
4. respiratory paralysis (pulse weak, breathing stops)

Question 7

Assessing depth of anesthesia: jaw tone

Answer 7

open the animal’s mouth; if the jaw is relaxed and easy to open, then the animal is adequately anesthetized. if there is resistance, then the animal is too light

Question 8

Assessing depth of anesthesia: swallowing reflex

Answer 8

gently pull on the tongue; if chewing and swallowing can be seen the animal is too light. when tongue is not retracted, the animal adequately anesthetized

Question 9

Assessing depth of anesthesia: withdrawal reflex

Answer 9

gently extend one leg and pinch the web of skin between the toes or the footpad with your fingernail; a positive reflex is indicated by the pull back of the leg (flexion)

note: this reflex may be preserved in some anesthetized animals

Question 10

Assessing depth of anesthesia: palpebral reflex

Answer 10

gently touch the medial canthus of the eye (the corner of the eye nearest the nose); the animal will blink its eyelid if not adequately anesthetized

Question 11

Assessing depth of anesthesia: corneal reflex

Answer 11

gently touch the cornea of the eye with a moistened gauze pad or Q-tip swab; the animal will blink its eyelids if not adequately anesthetized

Question 12

What are criteria for selecting an ideal euthanasia method/agent?

Answer 12

• rapid death without signs of pain, panic, distress
• minimum time to loss of consciousness
• reliable, reproducible
• safety to personnel
• minimal undesirable effects
• minimal environment impact
• simple easy to use equipment