Transcript ALAT Chapter 14 - Arizona Branch of AALAS

Chapter Fourteen
Euthanasia
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Research Techniques
 Previous units in this text have dealt primarily
with the laboratory animal technician’s approach
to animal care, environment and basic science.
 This last unit is devoted to research procedures
that involve animals.
 Commonly, these procedures are performed or
monitored by laboratory animal technicians.
 Also presented is a section describing some of
the common research methods most animal
technicians will observe as part of their animal
care duties.
Euthanasia
 Euthanasia is “act of inducing painless death.”
 Other terms are; “put to sleep” or “sacrifice.”
 AVMA, in its 2000 Report of the AVMA Panel on
Euthanasia, published criteria for painless death.
Report is recommended reading for any technician
who wants to develop a thorough understanding.
 Experiments require tissue exam after death.
 Painless methods of euthanasia fail to halt
reflexive body actions immediately after death.
 Emotional distress experienced as a result of
euthanizing an animal is a perfectly normal.
Euthanasia II
 Everyone involved in euthanizing
animals will experience anxiety at
some time or another.
 Some people will be more affected
than others, & the procedure is never something
you should get used to.
 To be more at ease with the use of various
euthanasia procedures, animal technicians must
have a basic understanding of subject.
 This understanding will ensure the procedure is
always performed in a caring, humane & safe
manner, with minimal anxiety for animal.
Euthanasia Methods
 Chemical or physical
 Chemical - either inhaled or injected
Several are actually anesthetic agents that when given
as an overdose result in rapid, painless death.
 Physical methods require mechanical devices.
 Intravenous injection & cervical dislocation
require considerable practice.
 Handle in a way that avoids fear & apprehension.
 Not done in presence of other animals.
 Verified by determining that heart has completely
stopped beating & all respiration has ceased.
Inhalant Chemicals
 Methoxyflurane, isoflurane and halothane are
nonflammable, non-explosive inhalants.
produce rapid anesthesia
 Cotton soaked w/ liquid anesthetic placed in
bottom of chamber, under a grate, so animals
cannot come in contact with cotton.
 After liquid has vaporized in chamber, animals
are placed in chamber and cover is secured.
CO2
 CO2 reasonably safe for handler and effective &
inexpensive, especially for rodents.
 Its use does not require a fume hood if the room
is well ventilated.
 Compressed gas, usually a mixture of oxygen &
CO2, is supplied in a metal cylinder.
Carbon dioxide is colorless, odorless & heavier than
air, and is easily emptied from cylinder into a topopening chamber or bag.
Neonatal animals require much
longer exposure to CO2 in order
to cause death.
Injectable Chemicals
 4 injectable agents listed in AVMA
report as “Acceptable IV.”
 IV is preferred but some can be given via other
routes; decision must be left to an individual with
experience & expertise.
 Pentobarbital (barbiturates) produces rapid
anesthesia & death.
safe when used as intended & usually inexpensive
disadvantage is potential for human abuse
 Drug Enforcement Admin. (DEA) controlled
 Careful record keeping & inventory control of
these substances is necessary.
Physical Methods
 Cervical dislocation is a method of rapidly
breaking the neck.
Useful when tissues must be free from drug residues.
Only for poultry, mice or rats weighing <200 g, &
rabbits weighing <1 kg.
Sedate or lightly anesthetize prior to cervical
dislocation if O.K. with experiment.
 Decapitation using guillotine; head is severed at
atlas/axis joint of neck.
Only use on conscious animals if
IACUC has verified it is essential for
project & prior induced unconsciousness would invalidate research data.
Additional Reading
“2000 Report of the AVMA Panel on Euthanasia.” J.
Am. Vet. Med. Assoc. 202(2), 2000.
Fox, J.G., Cohen, B., and Loew, F.M. Laboratory
Animal Medicine. Academic Press, Orlando, FL.,
1984.
Pekow, C.A. “Suggestions from Research Workers
for Coping with Research Animal Death.” Lab
Animal, 23 (10), 1994.
Walshaw, S.O. “Animal Death and Human Emotion
in the Laboratory.” Lab Animal, 23 (10), 1994.