Page 690 - WSAVA2017
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An Urban Experience
B.D. Wright1
1Veterinary Anesthesiologist — Integrative Pain Management Specialist,
Anesthesia Tenants: Regardless of species, I tend to approach animals that have a human bond similarly. Small mammals that are pets typically fall in this category. Very small patients, regardless of species, have high metabolic rates, and thus shorter periods of tolerance
for sub-optimal physiological parameters (oxygenation). Uptake, distribution and elimination of parenteral or inhaled drugs will also be more rapid. Rate of cooling (or rewarming) is very rapid due to high body surface area.
1. Assess and manage stress, anxiety and pain
2. Premedicate in concert with item #1, with judicious attention to timing of procedure
3. Start anesthetic support, as indicated, concomitant with, or prior to, induction
4. The pharmacology of anesthetic induction and maintenance
5. Appropriate withdrawal of support during recovery
6. Ongoing analgesia
Prior to interventions: Risk of hypoglycemia, and in many cases, resistance to vomiting indicates that fasting should not take place. A large gastric volume can be problematic during anesthesia, so pelleted food and water alone should be given for the 2-4 hours prior to anesthesia. Rabbits, guinea pigs and ferrets may benefit from actual fasting for a couple of hours, at most.
Non-pharma is integral- medications can be added, but in small mammals this is uncommon
I. Environment (warm, food and water still present, noise)
II. Lavender lotion for handling (odor)
Premedicate (or restraint)
A. Small mammals in general: Injectable medications smooth anesthetic induction, even if inhalants are chosen for induction as well as maintenance. Also, consider intubation doses of inhalants (3 MAC) relative to toxic doses (4 MAC), and the advantage
of increasing this therapeutic gap. Use caution extrapolating doses from research studies, that may not have been designed for recovery (use text such as Quesenberry/Carpenter).
a. Opioids
b. Benzodiazepines
c. Alfaxalone
d. Ketamine (combined)
e. Alpha-two agonists (deprioritized in domesticated pets)
B. Ferrets: IV catheterization after sedation is very possible (cephalic, saphenous, jugular- thick skin so consider pilot hole and/or topical lidocaine)- consider IV induction.
C. Rabbits: IV catheterization after sedation is very possible (cephalic, saphenous). Thin skin- use care with shaving.
1. Consider terbutaline with premedications- clinical impression of less respiratory arrest
2. Atropinases- consider glycopyrrolate with premedication if an anti-cholinergic is needed
D. Guinea Pigs:
E. Chinicillas:
F. Hedgehogs: premedication facilitates handling for induction
G.Sugar Gliders:
Support and monitoring
A. Heat support short start at the time of premedication (prewarm the area where prep will occur). Heat support continues throughout the procedure and recovery. Consider perforated forced air devices that surround the patient with warmed air.
B. IV fluid support- rabbits require high fluid rates (10-20 ml/kg/hour). Others should have typical maintenance (5-10 ml/kg/hour). If there is not an IV catheter, this can be given pre-warmed SQ at the time of induction.
C. Transfusion parameters are very similar to other mammals (PCV <20; Blood loss >30% blood volume). Blood volume approximately 10 mL/kg.
D. Very small patients should have non-heparinized saline used for flushes
E. Monitoring intensity needs to balance with level of complexity of case, fragility of patient, and NFS. See notes from monitoring lecture.
Induction and Intubation-
A. Small mammals in general: Length of procedure
and ability to support and monitor help dictate the priority for speed (NFS) versus increased control and complexity.

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