Wisdom from the Field: Anesthetizing a Penguin

At Mallard Medical we have the honor and privilege of being connected to some of the brightest young Veterinarians in the world. Recently I was observing a thread in an email list that I am a part of I and I thought it was not only fascinating, but incredibly helpful.

Laura A. B. Aguilar is an Anesthesia and Analgesia Resident at the University of Florida. She responded to a question regarding penguin anesthesia for diagnostic imaging of a reproductive tract disease. I found Laura’s response insightful and asked if I could post her response on our Mallard blog. Enjoy this incredible information from Laura.

-It is essential to know the age and the species before any sedation/anesthetic procedure. There is variation between species in regard to anesthesia, in which smaller species (i.e. African penguins) tend to have a faster metabolism, and usually higher doses are needed. Also, age could be an important variable. In a study we performed during my Zoo Med Residency program at Georgia Aquarium, we found a variation between juvenile and adult African penguins. Juvenile penguins are more tolerant to higher doses of drugs for sedation/anesthesia than older penguins.

-For sedation/premedication we used different doses of midazolam (0.5-2 mg/kg) and butorphanol (1-2mg/kg) with variable results. We always reversed the midazolam with flumazenil (0.01mg/kg). In some penguins, this combo worked well, but in other penguins did not work as expected generating excitement after premedication and prolonged recoveries. For short procedures, what worked best for us was using isoflurane induction without premedication. Common complications using inhalants were apnea/hypoventilation, bradycardia, and regurgitation, but recovery was very fast.

-For venous access, we used the right/left jugular or dorsal coccygeal vein/sinus for blood collection and the brachial, metatarsal, or interdigital veins for catheter placement.

-Hyperthermia is usually a common complication with some penguin species, however in other species hypothermia can also be a potential complication. Therefore, monitoring temperature is extremely important. Esophageal probes provide more accurate measurements of body temp than cloacal measurements.

-The last consideration is that penguins tend to present subclinical respiratory disease (most common Aspergillosis) which may become a complication during anesthesia. It´s ideal to get CBC, chemistry, and radiographs before any anesthetic procedure. We used to take radiographs on awake penguins without the need to sedate/anesthetize them using plastic tubes to contain them. This also sometimes works with CT scans depending on the penguin’s temperament.