Exam 1 - Euthanasia: Lecture & Critical Thinking Flashcards
what are the 5 most important aspects of evaluating euthanasia methods?
- ability to induce loss of consciousness & death with minimum pain & distress
- time required to induce loss of consciousness
- documented emotional effect on observers or operators
- safety for predators or scavengers should the remains be consumed
- environmental impacts of the method or disposition of the animals remains
what is the definition of an ‘acceptable’ method of euthanasia?
those that consistently produce a humane death when used as the sole [primary] means of euthanasia
what is another term used for ‘acceptable’ method of euthanasia?
fully acceptable
what is the definition of ‘acceptable with conditions’ method of euthanasia?
equivalent to acceptable methods when all criteria for application of a method can be met
what is another term used for an ‘acceptable with conditions’ method of euthanasia?
conditionally acceptable
what is the definition of an ‘unacceptable’ method of euthanasia?
those methods deemed inhumane under any conditions or that the [AVMA panel] found posed a substantial risk to the human applying the technique
what are the 2 general categories for primary methods of euthanasia?
pharmacologic agents (overdose**) - inhaled is conditionally acceptable & injectable is fully acceptable
physical - conditionally acceptable
why is an inhaled pharmacologic agent used as a primary method of euthanasia conditionally acceptable?
you must get the animal to a point where it is irreversible - make sure heart & respirations have stopped
what are the 2 main requirements for using physical methods of euthanasia?
- operator must be proficient
- equipment must be kept in good condition
what is an example for keeping equipment in good condition regarding using a guillotine as a physical method of euthanasia?
sharpening services - vinyl tubing to confirm sharpness, only a few companies
T/F: guillotines are largely used in research facilities
true
T/F: ‘after-effects’ of euthanasia are more commonly seen with physical methods of euthanasia, so you should prepare yourself, staff, & clients for what that may look like
true
what are the major signs associated with ‘after-effects’ of physical methods of euthanasia?
- leg kicking!!!!!! large muscle groups involved, & can be vigorous
- muscle twitching
- skin twitching
- death ‘sigh’ or ‘hiccup’ - diaphragm
why do ‘after-effects’ occur in euthanasia?
effect of spinal stimulation & residual ATP storage in the muscle
leg kicking is not uncommonly seen with what physical method of euthanasia?
captive bolt
what is the point of using a secondary method of euthanasia?
when you’re not sure if irreversibility is achieved
when should the secondary method of euthanasia be used?
only used after you are absolutely sure the patient is unconscious
what are 3 reasons you should use a secondary method?
- ensures the animal can’t return to consciousness
- in case primary only stuns/knocks them out or goes wrong (dislocation of T13-L1 instead of C1-C2)
- pharmacologic - can be a fine line between dose & overdose, need at least 3x the upper anesthetic range, especially common in drugs not labelled for euthanasia
what is the most common secondary method of euthanasia used that works well for all species? why is it ideal?
penetration into the thorax - removes thoracic negative pressure, so it ensures that the heart & lungs stop
how is penetration of the diaphragm used as a secondary method of euthanasia?
if the abdomen is open (post surgical euthanasia)
in necropsy, you can assess lungs, & you want to see them shrink back into the chest showing that negative pressure was there
what species will thoracic penetration not be useful for a secondary method of euthanasia?
amphibians - some are lung-less
other than thoracic penetration, what are 2 other secondary methods?
- cervical dislocation
- exsanguination - animal must be unconscious first for transection of major vessels (axial a./v. easiest to perform in some rodents/avians)
when disposing of euthanized animals, what must be considered?
environmental effects!
barbiturates in carcasses - access to wildlife
rendering (non-edible) limits
what is the procedure of using injectable anesthetic overdose for small rodents?
pentobarb, beuth-d
largely by IP route - lower right quadrant is preferred, enter at a shallow angle, target is the last row of nipples
why is the lower right quadrant the preferred target for injectable anesthetic overdose for small rodents?
avoid urinary bladder, cecum, gi - animal can void it out
what is the fastest method not requiring a lot of technique for euthanasia of small rodents?
gas anesthetic overdose using isoflurane, sevoflurane, or desflurane
what is the disadvantage of using gas anesthetic overdose for small rodent euthanasia?
there is an aversive smell - distress in the first minute
if you use gas anesthetic overdose for euthanasia of small rodents, how can a mask be used? what about an induction chamber?
mask - only have to cover the nose because there are obligate nasal breathers
induction chamber - must block the scavenge outlet
how can you reduce occupational hazards associated with gas anesthetic overdose of small rodents?
air tight container during the euth
once death is assumed, safe, active scavenge
open chamber & confirm death
perform secondary method to be sure
how is using CO2 anoxia as a method for small rodent euthanasia classified?
acceptable with conditions - use an induction chamber or mask/nose-cone
what is the flow rate used for CO2 anoxia as a method for small rodent euthanasia classified? what are some other requirements?
using 30-70% CO2 displacement rate
requires flow-meter & compressed gas cylinder
what animals cannot use CO2 anoxia as a method for small rodent euthanasia? why? what can you do instead?
neonates!!
highly CO2 resistant, > 50 minutes
IP anesthetic overdose or decapitation
T/F: dry ice to induce CO2 anoxia is an acceptable with conditions method of small rodent euthanasia
false - unacceptable
if you don’t have CO2, nose-cone/induction chamber, or access to anesthesia, what method can be used as a last resort for adult rats or smaller rates?
bell-jar method
what materials are needed for the bell-jar method?
liquid anesthetic
cotton ball
tea ‘ball’-type strainer
wide mouth, air tight plastic or glass jar
how is the bell-jar method performed?
place rodent in the jar first because anesthetic smell is highly aversive - place strainer holding anesthetic soaked cotton ball in
when are physical methods best used in rats & mice?
perform after heavy sedation/anesthesia
what are the patient requirements for cervical dislocation in rats & mice?
all post-weanling adult mice & rats that are 200g or less
why can’t cervical dislocation be used in rodents greater than 200 grams?
their nuchal ligament is too thick, so it’s not reliable
what should be palpated prior to cervical dislocation of rats & mice? what should be done after?
palpate C1-C2 separation
always use a secondary method