08. AVMA euthanasia guideline 2020

Adjunctive methods of euthanasia for swine

exsanguination, pithing

Electrocution is Acceptable With Conditions in swine euthanasia, what is the age indication?

If >3 days of age

What are the acceptable methods for euthanasia for lab fish (specifically zebrafish)

o MS 222 immersion

§ Adults & at or > 14dpf – for 30 minutes **NEW** following loss of rhythmic opercular movement

§ MS 222 alone NOT effective for ZF eggs, embryos, or larvae (< 14 days old)

o Rapid chilling @ 2-4C

§ Adults - 10 m past loss of opercular movement

§ Fry (4-14 dpf) - 20 min past

§ Not effective if <3dpf

o Immersion in dilute sodium or calcium hypochlorite – up to 7dpf

Rapid chilling is acceptable with conditions for other lab fish, specifically which ones?

tropical & subtropical sternothermic

Acceptable methods for euthanizing lab frogs (xenopus and rana)

· physical method while anesthetized.

· **NEW** sodium pentobarbital IV, intracelomically, or in the lymph spaces – acceptable

o CAVEAT – high doses often required & inconsistent time to loss of consciousness

Who is responsible for training personnel to perform euthanasia?

Each facility or institution where euthanasia is performed (whether a clinic, laboratory, or other setting) is responsible for training its personnel adequately to ensure the facility or institution operates in compliance with federal, state, and local laws.

define acceptable with conditions euthanasia method

May require certain conditions to be met to consistently produce humane death, may have greater potential for operator hazard, are not well documented in the scientific literature, or may require a secondary method to ensure death.

define unacceptable euthanasia method

o Methods deemed inhumane under any condition or the POE found posed a substantial risk to the human operator

define adjunctive methods of euthanasia

o that should not be used as a sole method, but that can be used in conjunction with other methods

What sign is use to gauge unconsciousness in animals?

loss of righting reflex

Agents that induce ____ prior to unconsciousness are unacceptable

convulsions

What cannot determine exact onset of unconscious ness?

EEG or electroencephalogram

What 3 signs must be present to confirm unconsciousness?

absence of corneal reflex, eyelash reflex, or rhythmic breathing

What sign can be used as the only sign to confirm death?

Rigor mortis

What is the definition of pain according to International Association for the Study of Pain (IASP)?

An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.

Activity induced in the nociceptor and nociceptive pathways by a noxious stimulus is not pain, which is always a psychological state, even though we may well appreciate that pain most often has a proximate physical cause."

What agents should not be relied on to produce a truly unresponsive, disconnected, unconscious state, regardless of dose administered?

immobilizing, tranquilizing, or sedatives

What are the 3 main mechanism of euthanasia and examples of them?

depression of neurons - pentobarbital

hypoxia - displace oxygen with other gas

physical disruption of brain activity

What act protects wild animals and scavenging species from secondary poisonings (pentobarbital in animal tissue)

The Migratory Bird Treaty, the Endangered Species Act & the Bald and Golden Eagle Protection Act carry civil and criminal penalties

What are some recommendations from UFW to ensure scavengers cannot eat poisoned tissue?

o Incinerate/cremate animal remains whenever possible

o Immediately bury deeply according to local/state laws

o If ground is frozen, securely cover

o Review/modify local landfill practices to prevent access of scavengers

o Educate client on proper disposal, include warning on disposal of remains on euth consent form, tag bag with ‘poison’

Rendered ruminants cannot what?

be fed to ruminants

Magnesium salts are _________ as sole agent for euthanasia in many invertebrates

acceptable

2 multiple choice options

When using gas, unconsciousness depends on?

displacement rate, container volume, and gas concentration

If you habe a high initial gas concentration, uncinsouness happens faster but?

its more distressful

Inhaled agents for euthanizing Reptiles, amphibians, and diving birds and mammals is less than ideal because?

have a great capacity for holding their breath and for anaerobic metabolism

Noninhaled methods of euthanasia should be considered for these species and a secondary method is required to kill the unconscious animal.

What is the shortcoming of using Enflurane to euthanize animals?

At deep anesthetic planes, convulsions may occur. Enflurane is an effective agent for euthanasia, but the associated seizure activity may be disturbing to personnel.

Why can't nitrous oxide be used as sole gas agent for euthanasia?

effective dose is >100% so cannot be used alone or will produce hypoxia prior to respiratory or cardiac arrest

what gas is explosive and flammable?

diethyl ether

What is the solubility of Nitrous oxide, Methoxyflurane, Iso, Halothane, Enflurane and Desflurane in the order of most to least soluble?

Solubility: “Man HE Is Not Dead:

Methoxyflurane > Halothane > Enflurane > Iso > Nitrous oxide > Desflurane

What is the maximum exposure of halogenated inhaled anesthetics to personnel?

concentrations for halogenated inhaled anesthetics are not to exceed 2 ppm (1-hour ceiling) when used alone, or 0.5 ppm for halogenated anesthetics combined with 25-ppm N2O

What is the 8hr time limit cap for N2O, halothane, and enflurane?

50ppm

50ppm

75ppm

Inhaled Anesthetics are useful to be used in animals < ____ kg?

7

What is the order of preference for using inhalant in euthanasia?

Order of preference is isoflurane, halothane, sevoflurane, enflurane, methoxyflurane, and desflurane, with or without N2O.

“I Hate Seeing Every Mouse Die”

What gas is not acceptable at all?

Ether

what is the human risk associated with very low chronic exposure to CO?

CV disease and teratogenic

When using CO must ensure electrical equipment is?

spark free and explosion proof

CO is an acceptable euthanasia method with condition. What CO concentration should be inside the chamber after animals are placed in?

The CO flow rate should be adequate to rapidly achieve a uniform CO concentration of at least 6% after animals are placed in the chamber (unless neonate pig - less agitating if gradual rise)

N2 and Ar are aversive in rats, minks and dogs. They are not aversive in which two animal species?

chickens or turkeys

less head shaking and open-beak breathing than birds exposed to CO2

N2 and Argon is acceptable with conditions for what two species?

chickens and turkeys

Ar or N2-CO2 gas mixtures is acceptable with conditions for euthanasia of pigs, provided animals can be directly placed into a < ______% O2 atmosphere and exposures times > _____ minutes

< 2% O2 atmosphere and exposure times > 7 minutes are used.

Use of Ar or N2 is unacceptable for other mammals.

Carbon dioxide has the potential to cause distress in animals via three different mechanisms

(1) pain due to formation of carbonic acid on respiratory and ocular membranes,

(2) production of so-called air hunger and a feeling of breathlessness, and

(3) direct stimulation of ion channels within

the amygdala associated with the fear response

When do nociceptors respond to CO2 with pain?

40%

What pigs are excitable and react poorly to CO2 stunning?

Hampshire, german, landrace

What is the recommended displacement of Carbon dioxide?

a displacement rate from 30% to 70% of the chamber volume/min is recommended

How long should CO2 flow be maintained after respiratory arrest?

Whenever gradual displacement methods are used, CO2 flow should be maintained for at least 1 minute after respiratory arrest.

Can conscious rodents be immerged into a container prefilled with 100% CO2?

The practice of immersion, where conscious rodents are placed directly into a container prefilled with 100% CO2, is unacceptable.

What are some special considerations for CO2?

D0 mice and rats?

Newly hatched chicks?

adult minks?

Rabbits?

o D-0 mice & rats – 100% CO2 for 35-50 min

o Newly hatched chicks - >60% CO2 for > 5 m

o Adult mink – 5 m of 100% works but not 70% CO2

long exposure times

What species is CO2 euthanasia not acceptable for?

Rabbits at all

Should you expose animals to O2 when using CO2?

No, no advantage and not recommended

If an animal is anesthetized w/ inhaled anesthetics before should they be exposed to CO2 for euthanasia?

- there is no advantage for using CO2 after inhaled anesthetic exposure, also need to prevent rapid recovery during wash in of CO2 and wash out of anesthetic

Can animals euth by injectables enter food chain?

No

The only time you can use a paralytic FIRST (on awake animal) is if ______ and this must be followed up immediately by another euthanasia method.

wild or feral and otherwise “uncapturable”

You cannot combine euthanasia drug and _____ into 1 syringe

paralytic - paralytic works before euth

IF IV is not an option:

§ IP or intracoelomic of a _____ is acceptable

· intracoelomic MS222 is acceptable for some poikilotherms

· these routes will make stages I & II slower.

§ Intra-abdominal is acceptable for invertebrates with ____ circulatory systems.

§ Retro-orbital in mice of no more _____ – death within 5 seconds = acceptable with cond.

§ IO injections awake can be painful due to solution viscosity.

· Reduce pain w/

-“non-irritating barbiturate or other approved solution is acceptable”

-open

-200 ul of ket/xy, must be w/in 5 s

-analgesics, slower injection, etc. must be in preexisting IO catheter

What method is unacceptable in awake mammals and birds?

What are the 2 exceptions?

- intracardiac, IO or IO catheter placement, intrasplenic, intrahepatic or intrarenal

-intrahepatic in cats and IC in snakes and reptiles (if heart is standard area of venous access)

What methods are unacceptable in all awake animals?

IM (except ultrapotent opioids like etorphine & carfentanil and IM-approved inject anesthetics), SC, intrathoracic, intrapulmonary, intrathecal & other nonvascular injections

What drugs are FDA approved to be used to euthanize aquatic animals?

No FDA approved drugs for euthanasia of aquatic animals

When can a topical agent be used to euthanize an animal?

When skin is highly permeable and substance is nonirritating and rapidly absorbed (amphibians & 20% topical benzocaine)

All barbituric acid derivatives used for anesthesia are _________ for euthanasia when administered IV. Which barbiturate is the most commonly used euthanasia agent?

acceptable; Sodium pentobarbital (Schedule II)

2 multiple choice options

What are the general recommendations for barbuturic acid derivatives/pentobarbital combos?

o Preferred method for dogs, cats, small animals, horses

o IP or ICoelom used only if IV would be stressful or dangerous

o ICardiac, IM, IH, IRenal – only if unconscious or anesthetized (except IH for cats)

What tissue artifacts occur due to barbuturic acid derivatives/pento combos?

splenomegaly

Tributame(schedule III-controlled) is an ____________ euthanasia drug for ____. When is it acceptable for cats? Why? What is the only method of delivery?

acceptable, dogs

-only if pento not available - breathe agonally

IV

_______ has been used transmucosally in a lollipop form to euthanize captive ____________

Carfentanil (opioids); large apes

act on μ receptors to cause profound CNS depression, with death secondary to respiratory arrest.

Etorphine is another ultrapotent opioids

Ultrapotent opioids are only acceptable with what conditions?

-other method is dangerous/not possible

-second person must be available

T61 - not available in US - disadvantage?, acceptable only if given?

slow IV injection to avoid dysphoria, must restrain

IV only

Dissociative and alpha two agonists are acceptable with conditions. What are the conditions?

§ euth dose has been established

§ 1st step of 2 step.

§ Secondary means in already anesthetized animals

IV preferred, IM okay if IV not option

Potassium Chloride and Magnesium Salts are ______ when used in conscious vertebrate animals; _________ if injected IV or intracardially in an unconscious animal or animal under general anesthesia to induce cardiac arrest and death.

Unacceptable; Acceptable

acceptable only when other methods are unavailble or not feasible

Chloral Hydrate & α-chloralose(1,1,1-trichloro-2,2,-dihydroxy-ethane)

Unacceptable - sedate but unless combined w/ other drugs anesthesia is delayed

-better products out there

Death caused by hypoxemia

When is alcohol acceptable?

-step 2 in finfish (after rendered insensible)

-IP in mice used for antibody production

---mice at or >35d of age (if less than not acceptable)

---NOT for rats - too large volume needed and prolonged time

Tribromoethanol is acceptable under what conditions?

AVERTIN!!!

-low concentration as second step for finfish (immersion in 70% is NOT acceptable)

-mice >35d of age (never larger animals)

What species can Tricaine Methanesulfonate (MS 222, TMS) be used on?

FDA approved (Finquel and Tricaine-S only) for temporary immobilization of finfish, amphibians, and other aquatic, cold-blooded animals.

How should MS222 be prepared and stored?

buffered with sodium bicarbonate to pH of 7 to 7.5

The stock solution should be protected from light and refrigerated or frozen if possible. The solution should be replaced monthly and any time a brown color is observed.

How does the potency of MS 222 change in respect to water temperature?

Potency is increased in warm water and decreased in cold water.

When using MS222, how long do you have to wait after loss of rhythmic opercular movement to ensure death?

Immersion of finfish in solutions of MS 222 for 30 minutes following loss of rhythmic opercular movement

Death is due to decreased nervous and cardiovascular function.

Intracoelomic injection of MS 222 is __________ method of euthanasia for X. laevis and possibly other amphibians.

not an acceptable

Injection of MS 222 is not appropriate for finfish as rapid excretion via the gills renders it ineffective by this route.

2 multiple choice options

What is the withdrawal time for food fish with MS222

21 days

What Occupational hazard can MS 222 cause in human?

Occupational exposure to MS 222 has been associated with retinal toxicity in humans. Can't go into food chain

mechanism of action for benzocaine?

base blocks voltage gated Na+ channel (CNS and CV

Benzocaine hydrochloride is water soluble and can be used directly for either anesthesia or euthanasia of finfish and amphibians. Does it need to be buffered?

Topical 7.5-20% benzocaine HCL gel on amphibian’s ventrum is effective for anesthesia and euthanasia in some species and doesn’t require buffering (if it's HCL)

Benzocaine hydrochloride gel and solutions are ________ agents for euthanasia for NON FOOD finfish and amphibians.

acceptable

2 multiple choice options

Clove Oil, Isoeugenol, and Eugenol are ___________ agents of euthanasia for finfish.

acceptable with conditions

2 multiple choice options

What is the mechanism of Clove Oil, Isoeugenol, and Eugenol ?

inhibition of voltage-sensitive sodium channels within the nervous system

Clove oil is a human risk as it's a ______

carcinogen and possible paralytic

What species is it acceptable for

non-food fish

2-phenoxyethanol is an acceptable method of euthanasia for non-food finfish under certain circumstances

1 step immersion

Finfish should remain in solution for at least 10 min after cessation of opercular movement

MOA is unknown

Quinaldine is an _________ method of euthanasia for non-food finfish under certain circumstances (1 step immersion)

acceptable

2 multiple choice options

Quinaldine has lower water solubility it must be dissolved in what? It also must be buffered

ethanol or acetone

Metomidate- its listing in the Index makes extralabel use (eg, its use for euthanasia) ________

illegal.

1 multiple choice option

Sodium hypochlorite has been used to euthanize ________ and ________ zebrafish up to _____ days after fertilization

unhatched and hatched zebrafish up to 7 days after fertilization

Hypochlorites are ________ as the sole means of euthanasia of organisms beyond these embryonic and larval stages.

unacceptable

2 multiple choice options

What are the recommendations for sodium hypochlorite?

o Acceptable at 1-10% conc for embryos and <7 dpf larva.

o Can only be used as 2nd step in 2 step method > 7 dpf.

o Once the develop nociceptive abilities – no longer acceptable as sole agent

Formaldehyde acceptable for _______ as these invertebrates lack nervous tissue

Porifera (sponges)

Formaldehyde acceptable as an adjunct for ________ and ______ AFTER they are unconscious ( using MgCL)

Coelenterates (comb jellies, corals, anemones) & Gatropod mollusks (snails & slugs)

Formaldehyde unacceptable as adjunct or primary for which species?

all others

Lidocaine hydrochloride given ______ is acceptable as a secondary method in anesthetized animals with what conditions?

intrathecal

-other methods unavailable, cost prohibitive, and proper carcass disposal can be assured

What injectables are only acceptable AFTER the animal is already unconscious?

magnesium sulfate, KCl, NMBs

What 3 physical methods of euthanasia can only be done as adjuncts?

exsanguination, stunning & pithing

Thoracic compression is only an ______ method.

adjunctive

1 multiple choice option

What are the signs of an effective Penetrating Captive Bolt?

immediate collapse and a several-second period of tetanic spasm, followed by slow hind limb movements of increasing frequency.

The corneal reflex must be absent and the eyes must open into a wide blank stare and not be rotated.

Where should the captive bold be placed?

directly against head

aim the same way you would for a gun shot

Penetrating Captive Bolt is _________ for horses, ruminants, swine, rabbits, dogs, and poultry.

Acceptable with conditions

2 multiple choice options