Euthanasia Flashcards
what is the definition of euthanasia
“a good death”: act of ending life in a way that minimizes or eliminates pain and distress
how does euthanasia differ from assisted suicide
in assisted suicide the physician prescribes but does not administer the drug, therefore it is not euthanasia
what is Orthotanasia
not artificially extending the dying process; pulling the plug
what is humane slaughter
process and methods to kill animals for commercial reasons; applies to individual animals and large scale; includes transport and handling before unconsciousness and death; not always euthanasia
what is depopulation
- rapid destruction of several animals
- usually relates to emergency
what are the 3 classifications for depopulation
- preferred
- permitted
- not recommended
what are the classifications of euthanasia
- acceptable
- acceptable with conditions
- not acceptable
what are the goals of euthanasia (3)
- achieve irreversible unconsciousness
- brain, followed by respiratory and cardiac arrest
- minimize pain, fear, anxiety
what are the ways to minimize fear, anxiety and stress during euthanasia
- sedation whenever possible
- minimal restraint
- experience, training, sensitivity, compassion
what should NEVER be used in conscious animals
neuromuscular blocking drugs
what does perception of pain require
nerve impulses from nociceptors to reach a functioning CONSCIOUS cerebral cortex and subcortical brain structure
why does post-mortem twitching or movement occur
the muscles and nerves go through a phase of hyperexcitability
what causes agonal breaths
brainstem reflex in response to hypoxia (last respiratory pattern before terminal apnea)
it is important to communicate what to owners when discussing euthanasia
that it is irreversible (do not use terminology like putting to sleep)
what are the 3 death mechanisms
1) direct depression of neurons necessary for life function
2) physical disruption of brain activity
3) hypoxia
how do anesthetics cause unconsciousness
1) reduces info received by the cortex
2) prevents integration
when is inhalant anesthetic useful for direct depression of neuronal activity
- small animals or difficult to get IV
what is the best way to administer inhalant anesthetics as euthanasia
to achieve induction, followed by using injectables (2-step euthanasia)
what are the advantages and disadvantages of using inhalant anesthetic for euthanasia
benefit:
- easy to administer
disadvantage:
- animal may struggle
- slow
- not practical for large animals
- food residues in large animals
what are examples of parenteral injection/topical application/immersion for euthanasia by directly depressing the neurons (6)
- barbiturates
- T-61
- MS-222 (immersion)
- ultra-potent opioids
- ketamine/α2-adrenergic combos
- ethanol
what is the most common barbiturate used for euthanasia
sodium pentobarbital
what are the benefits of sodium pentobarbital for euthanasia
- potent, fast, long-acting, inexpensive, stable in solution
what are the disadvantages of sodium pentobarbital for euthanasia
- controlled drug
- commonly causes agonal breaths
- can be an irritant
how do we use hypoxia for euthanasia (how does it work)
exposes the animal to high concentrations of gases that displace O2 and/or impair oxygen transport by hemoglobin
what is the classification of CO2 for euthanasia
acceptable with conditions
what is necessary for using CO2 as euthanasia
gas displacement rate needs to be correct to prevent pain (caused by formation of carbonic acid when CO2 contacts moisture)
what is the classification of N2 and argon for euthanasia
acceptable with conditions
what makes N2 and argon acceptable with conditions
it is not directly aversive to pigs, chickens or turkeys but should not be used in any other mammals
what is CO and what does it do
colourless, odourless gas that is non-flammable and non-explosive when <12%; interferes with O2 uptake
what are the pros and cons of CO for euthanasia
Pros:
- loss of consciousness without pain and discomfort depending on species
- death rapidly if 4-6% concentrations used
Cons:
- convulsions
- agitation
- vocalization
what is the goal of using physical methods for euthanasia
destruction of the midbrain centers that control cardiac and respiratory activity
what is stunning
the process of rendering animals unconscious or immoble without killing them
what are the pros of physical methods for euthanasia
- if proper training with well-maintained equipment, may result in less fear and anxiety
- rapid, painless, humane and practical in some species
most methods of physical euthanasia have what status
acceptable with conditions (in some species only)
what is the target of physical methods for euthanasia (what area of the brain)
bilateral destruction of the rostral pons and medulla
what happens when to the animal when:
- bilateral destruction of the rostral pons:
- bilateral destruction of the medulla
- unilateral damage:
bilateral destruction of the pons: deep coma and brainstem death, pupils dilated and eyes not moving, extensor rigidity
bilateral destruction of the medulla: respiratory arrest
unilateral damage: short lived or incomplete cessation of responses
captive bolt can be used on what species
ruminants, horses, swine, poultry, laboratory animals, dogs
what is the most effective approach for an effective stun
midline frontal approach; direct the projectile towards the midbrain, pons and medulla
what other methods for euthanasia are only acceptable in anesthetized animals (unacceptable in conscious vertebrates!)
potassium chloride and magnesium salts; neuromuscular blocking agents
how do potassium chloride and magnesium salts cause death
cardio-toxic; induce cardiac arrest and death
how do we confirm death (4)
1) no pulse
2) inability to hear respiratory sounds and the heartbeat
3) lack of corneal reflex and deep pain
4) graying of mm
what sign alone can confirm euthanasia
rigor mortis
what is the preferred method for euthanasia of companion animals? how?
sodium pentobarbital IV with prior sedation; can give IP in small mammals and intra-organ ONLY if unconscious
what are the other acceptable methods for euthanasia of companion animals when IV pentobarbital is not available
- injectable anesthetic overdose
- T-61
- inhaled anesthetic overdose
- CO2
- gunshot
- penetrating bolt
- electrocution or KCl (under anesthesia)
what are unacceptable methods for euthanasia of companion animals
- drowning
- hypothermia
- SC, IM, IP or IT in awake patients
what is the best method of euthanasia of horses
pentobarbital or a pentobarbital combination IV; under anesthesia if possible
what are other acceptable methods for equine euthanasia besides pentobarbital
- captive bolt or gunshot
- adjunct methods (ex. KCl or magnesium sulfate under anesthesia)
what is the only case where you might use a NMB in an awake patient for euthanasia
in an awake horse if people could get injured before proper sedation/anesthesia; must be followed immediately by an appropriate method of euthanasia
what is the acceptable method of euthanasia in ruminants? acceptable with conditions?
acceptable: barbiturates
acceptable with conditions: penetrating captive bolt or gunshot (followed by an adjunct method such as exsanguination, potassium chloride/magnesium sulfate)
what is the preferred method of euthanizing swine
barbiturates (pet pigs); CO2, N2, argon (slaughter)
what are other methods for euthanizing pigs
- gunshot
- captive bolt (penetrating and non-penetrating)
- electrocution
- blunt force trauma in piglets >5kg
what are the acceptable methods of euthanizing poultry
- overdoses of injectable anesthetics
what are the acceptable with conditions methods of euthanizing poultry
- CO2, CO, N2, argon gases
- cervical dislocation, decapitation
- force trauma
- electrocution (followed by secondary method)
- gunshot
- captive bolt (penetrating and nonpenetrating)
what is an important consideration with amphibian and reptile euthanasia
the heart may beat after brain death
what is the acceptable method of euthanizing reptiles and amphibians
- pentobarbital
- MS-222 bath
confirm with adjunct method
what is an acceptable with conditions method of euthanizing reptiles and amphibians
- inhalant
- blunt trauma
what is an unacceptable method of euthanizing reptiles and amphibians
hypothermia
what is the recomendation for disposal of euthanized animals whenever possible
incinerate or cremate
