Small Mammals/Exotics

Question 1

What is are unique features of lagomorphs and rodents?

Answer 1

• They are obligate nasal breathers (very small, short airways), making intubation very difficult
• comparatively smaller lungs - but able to move more air via high vital capacity, low residual lung volume, and high chest wall compliance

Question 2

Why do small patients typically require higher drug dosages on a mg/kg basis than larger species?

Answer 2

Because their metabolic rates and oxygen consumption is much more per unit body weight

Question 3

Why is having a temperature-controlled environment very important for small species?

Answer 3

because they have a much higher surface area-to-volume ratio, making them prone to rapid heat loss and hypothermia

Question 4

What unique characteristic of rabbits, guinea pigs and chinchillas that makes them more susceptible to ileus during hospitalization and post-anesthesia?

Answer 4

They are hind-gut fermenters

• also, increased circulating catecholamines (ie. Stress/pain) can result in ileus as well!

Question 5

In which species is fasting not necessary prior to anesthesia, and why is this?

Answer 5

Lagomorphs and rodents; they cannot vomit due to their gastric anatomy

**ferrets and non human primate still should be fasted

Question 6

One may take up to how much of a small mammal’s blood volume in a systemically healthy animal? How much time should be allowed for a recovery period after this prior to sampling again?

Answer 6

• 10% of blood volume
• 1 month

Question 7

What types of drugs are preferred for initial induction and anesthetic maintenance in small mammals, due to their ease of administration, quick elimination, and dose standardization?

Answer 7

inhalants

Question 8

Why are insulin syringes or hub-less syringes recommended for small mammal anesthesia?

Answer 8

becaues when diluting drugs, the amount of drug present in the hub of a syringe can be significant (up to 0.07 ml)

Question 9

Which two drugs are the mainstay of analgesic care for peri-operative pain in exotics/small mammals?

Answer 9

Opioids and NSAIDs

Question 10

What type of breathing system should be used for these patients?

Answer 10

Non-rebreathing systems - minimizes dead space and preserves heat/humidity

Question 11

What materials/equipment should you have on-hand for performing anesthesia on these small mammals?

Answer 11

• Appropriate housing
• quiet environments
• gram scales/accurate small scales
• Trained assistant to monitor anesthesia
• non-rebreathing systems
• variety of facemasks
• variety of uncuffed ET tubes +/- ET tube connector if using IV catheter

Question 12

What is the calculation to approximate normal heart rate in small mammal species?

Answer 12

Heart rate = 241 x M_b^-0.25

M_b = body weight in kgs

Question 13

Where can you perform blood sampling from in a lagomorph?

Answer 13

• Jugular
• Cephalic
• Saphenous

Question 14

What is the preferred anesthetic protocol in lagomorphs?

Answer 14

• pre-med/sedation: Midaz + buprenophine (to avoid full mu GI effects)
• induction: IV propofol/alfaxalone, inhalant via face mask (may be more stressful) or IM alfaxalone
• post-op: NSAIDs, opioids, regional/local anesthesia

Question 15

In the case of an emergency, which anticholinergic should be used in rabbits, and why?

Answer 15

Glycopyrrolate (NOT atropine; Because rabbits have endogenous atropinases, rendering atropine ineffective in these patients

Question 16

Rodents are predisposed to hypoxia and hypoglycemia, why is this?

Answer 16

• Have a very high metabolic rate, thus high oxygen demand and they have low glycogen stores

Question 17

Where would you sample blood from in rodents?

Answer 17

• Jugular
• cephalic
• saphenous
• lateral coccygeal

Question 18

Why is intubation notoriously difficult in guinea pigs and chinchillas?

Answer 18

Because their soft palates are fused to the base of the tongue and access to the glottis is via the palatal ostium, which is difficult to position/visualize well

Question 19

Injectable drugs may be administered which ways in rodents?

Answer 19

SQ, IM. IV, IO, IP (intraperitoneally)

Question 20

IV catheters in lagomorphs can be placed where?

Answer 20

Marginal ear veins or IO (proximal humerus, femur or tibia)

Question 21

What is the anesthetic protocol in rodents?

Answer 21

• Pre-med/sedation: benzos and opioids, alpha2/ketamine, telazol, benzo/ketamine
• Induction: inhalants (lab animals - IP)
• Analgesia: buprenorphine and NSAIDs

Question 22

What is another place for blood sampling in ferrets under general anesthesia?

Answer 22

the cranial vena cava

Question 23

Ferrets typically only have to be fasted for 4 hours prior to surgery..why?

Answer 23

They have very rapid GI transit time

Question 24

What is the anesthetic protocol for ferrets?

Answer 24

• Pre-med: opioid (butorphanol or buprenorphine) + midazolam; alfaxalone for cardiac concerns
• Induction: inhalants
• Analgesia: opioids and NSAIDs