Euthanasia

Question 1

What are the AVMA euthanasia classes?

Answer 1

• acceptable
• acceptable w/ conditions
• unacceptable

Question 2

Criteria for an acceptable method of euthanasia?

Answer 2

• induces loss of consciousness & death w/ minimum pain & distress (includes competency of the administrator)
• time to loss of consciousness
• reliability
• irreversibility
• safety of personnel
• emotional effect on observers or operators
• compatibility w/ intended animal use & purpose (consumption, experimental)
• compatibility w/ subsequent evaluation, examination, or use of tissue
• drug availability & human abuse potential
• compatibility w/ subsequent evaluation, examination, or use of tissue
• drug availability & human abuse potential
• compatibility w/ sp, age, & health status
• ability to maintain equipment in proper working order
• safety for predators or scavengers should the animal’s remains be consumed
• legal requirements
• environmental impacts of the method or disposition of the animal’s remains

Question 3

what is ideal euthanasia?

Answer 3

1. depression of neurons necessary for life fxn (loss of consciousness)
2. hypoxia (cardiac & respiratory arrest)
3. physical disruption of brain activity & destruction of neurons necessary for life (loss of brain function)

Question 4

what are the options for euthanasia?

Answer 4

• chemical (inhalant or injectable/oral)
• physical

Question 5

what is important about our inhalant agents?

Answer 5

• isoflurane (irritating)
• halothane, sevoflurane (non-noxious odour)
• NO increases speed of onset
• chamber method < 7kg
• human exposure
• confirmation of death required
• not appropriate for reptiles, amphibians, diving birds, & mammals

Question 6

what is important about our inhalants?

Answer 6

• carbon monoxide/dioxide: used for dogs/cats in some humane societies & for rodents, birds; species dependent aversion
• CO (acceptable): signs of agitation, convulsions, muscle spasms, vocalization common (Ca/Fe); source is important; blocks O2 uptake by RBCs
• CO2: 30-40% needed for unconsciousness in Ca; 60% in Fe; <25% in birds (< 1 min)

Question 7

Why is carbon dioxide controversial?

Answer 7

• carbonic acid pain (respiratory/ocular mbs)
• breathlessness (respiratory acidosis - panic)
• direct stimulation of the amygdala (fear response)
• 7.5% CO2 INCREASES the pain threshhold
• > 30% anesthesia followed by death
• acceptable w/ conditions (unconsciousness prior to exposure preferred)
• gradual fill recommended

Question 8

what are noninhalant methods of euthanasia?

Answer 8

• BARBITURATES
• PENTOBARBITAL
• rapid, smooth
• controlled drug, need a licensed vet
• must be given IV
• confirmation of death required
• risk for scavenging (wildlife)

Question 9

what is important about barbiturates?

Answer 9

• most birds are anesthetized 1st (wing flapping, vocalization)
• can use in reptiles including Chelonians (turtles, tortoises)

Question 10

What is T-61?

Answer 10

• local anesthetic (tetracaine hydrochloride)
• general anesthetic (embutramide)
• neuromuscular blocking agent (mebezonium iodide)
• NOT a controlled drug (care recommended)
• concerns: improper administration (IV only) -> mammals: dysphoria if injected too quickly; respiratory paralysis (suffocation) before loss of consciousness -> birds: anesthesia immediate + EEG loss < 6 secs
• AVMA (acceptable) vs CCAC (not recommended)

Question 11

pentobarbital euth in Eq?

Answer 11

• IV required
• sedation or anesthesia recommended
• risk to scavengers

Question 12

intrathecal lidocaine after anesthesia for euth in Eq?

Answer 12

• longer to respiratory, cerebral, brainstem, & CV arrest compared to IV barbiturates
• audible heart beat 5 mins vs < 1 min
• EEG 2 min vs 20 sec
• sedation required
• little risk to scavengers

Question 13

What is tricaine methane sulfonate (MS-222) euthanasia?

Answer 13

• suitable for fish & most amphibians
• sodium bicarb required to buffer
• NOT controlled drug
• used as an anesthetic
• some reptiles IC (AVMA vs unacceptable CCAC)
• secondary method required to ensure death

Question 14

what are unacceptable agents of euthanasia?

Answer 14

• strychnine, nicotine, caffeine, cleaning agents, solvents, pesticides, disinfectants, & other toxicants not specifically designed for therapeutic or euthanasia use
• magnesium sulfate, potassium chloride, & neuromuscular blocking agents
• ACCEPTABLE W/ CONDITIONS (MAY BE USED FOR EUTH OF ANESTHETIZED OR UNCONSCIOUS ANIMALS)