Anesthesia and Analgesia
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|
Drug
|
Category
|
Mice
|
Rats
|
Gerbils
|
Guinea Pigs
|
Hamsters
|
|
Atropine |
Anticholinergic |
0.04 IM or SQ |
0.05 IM, IP |
0.02 to 0.05 SQ, IM, IP |
0.02 to 0.05 SQ, IM, IP |
0.02 to 0.05 SQ,
IM, IP |
| Ketamine +
Xylazine |
Dissociative
Anesthetic |
90-120 + 5-10 IM |
40 to 90 + 15
IP |
50 + 2 IP |
50 + 5 IP |
200 + 10 IP |
|
Ketamine + Xylazine + Acepromazine |
Dissociative Anesthetic |
100 + 10 + 5 IP |
22 to 44 + 2.5 + 0.75 IM |
May precipitate seizures |
|
|
| Ketamine +
Acepromazine |
Dissociative
Anesthetic |
100 + 2.5 IM |
30 to 75 + 2.5
to 3 IM |
|
125 + 5 IM |
150 + 5 IM |
|
Thiopental |
Barbiturate |
25 to 50 IV |
30 IV |
|
|
|
| Pentobarbital |
Barbiturate |
Neonate: 5 IP,
35 to 70 IV, 40 to 90 IP |
30 to 40 IP |
25 to 30 IP |
25 to 30 IP |
9 to 11.2 IP |
|
Isoflurane |
Inhalant Anesthetic |
1 to 3% to effect |
1-3 % to effect |
4% to effect |
1.5 |
4% to effect |
|
Source: ACC Handbook, 2008 |
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|
|
Analgesic
|
Mice
|
Rats
|
Gerbils
|
Guinea Pigs
|
Hamsters
|
|
Buprenorphine |
0.05 to 0.1 SQ 6 to 12 hours |
0.2 to 0.5 SQ 8 to 12 hours |
0.1 to 0.2 SQ 8 to 12 hours |
0.05 SQ 6 to 12 hours |
0.05 to 0.5 SQ 8
to 12 hours |
| Butorphanol |
0.05 to 5 SQ q
4 hours |
0.05 to 2 SQ q
4 hours |
|
|
|
|
Meperidine |
10 to 20 SQ/IP 2 to 4 hours |
25 to 50 SQ 2 to 3 hours |
|
10 to 20 SQ/IM 2 to 3 hours |
20 SQ/IM 2 to 3
hours |
| Pentazocine |
10 SQ 2 to 4
hours |
10 SQ 2 to 4
hours |
|
|
|
|
Source: ACC Handbook, 2008 |
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Cryoanesthesia or hypothermia, produced by chilling the
animal to near freezing temperature, may be used as a means
of anesthetizing neonatal mice and rats pups less than six
days of age. Their small size and body mass makes rapid
cooling feasible through surface cooling. They are resistant
to arrest of blood supply to the brain and tolerate extended
periods of 1º C body temperature without known negative
effects. Potential risks of hypothermia include ventricular
fibrillation, tissue hypoxia and metabolic acidosis on
warming.
When a need for hypothermia is demonstrated the following
guideline should be followed:
- To induce hypothermia, pups may be placed in a latex glove and immersed up to the neck in crushed ice and
water (2ºC to 3ºC) which requires a five to eight minute induction time
(two to three minutes to unconsciousness and three to five minutes to complete
blockage of neural transmission). Alternatively, pups may be
placed in a paper–lined tube and packed in crushed ice
which may require up to 15 minutes to obtain a surgical
plane of anesthesia. Analgesia for hypothermia induced by
these methods lasts approximately ten minutes.
- Do not place the animals directly on the cooling medium;
provide a cloth, paper, or other barrier material. Simply
placing conscious animals in a cold room or on an ice pack
are unacceptable as induction may take 30 to 45 minutes.
- The anesthetic state may be prolonged by placing the
hypothermic pup on an ice pack (3ºC to 4ºC). Studies have shown
that rodent pups will maintain a core body temperature of
approximately 5ºC when kept on an ice pack for a maximum of
15 minutes.
- Illumination of the surgical field should be fiber optic in
nature, because incandescent bulbs may cause inadvertent and
uncontrollable warming.
- After the procedure, avoid rapid rewarming because of
possible tissue damage. Until animals are fully conscious
they, cannot escape excessive heat generated by
incandescent lamps, heating pads, or other warming devices.
Pups can also be placed in an incubator at 33ºC for 20 to 30
minutes. Complete recovery typically requires 30 to 60 minutes.
- Supplemental oxygen may benefit the recovering animals.
References
Phifer, CB and Terry, LM. 1986. Use of hypothermia for
general anesthesia in preweanling rodents. Physiol. Behav.
38:887-890.
Danneman, PJ and Mandrell, TD. 1997. Evaluation of five
agents/methods for anesthesia of neonatal rates. Lab. Anim.
Sci. 47:386-395.
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