ICVA - International Council for Veterinary Assessment Exotic Animal Anesthesia Questions and Answers 1 — Questions and Answers
Question 1: A veterinarian is preparing to anesthetize a 12-year-old blue-and-gold macaw for a surgical procedure. Which anatomical feature is most critical to consider when selecting and placing an endotracheal tube in this patient?
- The presence of a diaphragm, which requires higher inflation pressures.
- The presence of complete tracheal rings, which contraindicates the use of a cuffed endotracheal tube. (Correct answer)
- The bifurcation of the trachea into bronchi within the cervical region, requiring a shorter tube.
- The presence of an epiglottis, which can make visualization of the glottis difficult.
Correct answer: The presence of complete tracheal rings, which contraindicates the use of a cuffed endotracheal tube.
Birds possess complete, O-shaped tracheal rings, unlike mammals which have C-shaped rings. Inflating a cuff on an endotracheal tube within this rigid structure can exert excessive pressure on the tracheal mucosa, leading to ischemia, pressure necrosis, and potential stricture formation. Therefore, uncuffed tubes are always recommended.
Question 2: A 2 kg domestic rabbit is scheduled for a dental procedure. The veterinarian wishes to use an anticholinergic to reduce salivary and respiratory secretions. Why is glycopyrrolate often considered a more effective choice than atropine in this species?
- Atropine causes significant and prolonged hypertension in rabbits.
- A high percentage of rabbits possess the enzyme atropinesterase, which rapidly hydrolyzes and inactivates atropine. (Correct answer)
- Glycopyrrolate provides superior postoperative analgesia compared to atropine.
- Atropine is known to cause severe gastrointestinal stasis in rabbits, while glycopyrrolate does not affect motility.
Correct answer: A high percentage of rabbits possess the enzyme atropinesterase, which rapidly hydrolyzes and inactivates atropine.
A significant portion of the rabbit population has a plasma enzyme called atropinesterase (or atropine esterase), which rapidly breaks down atropine, leading to a reduced efficacy and a much shorter duration of action. Glycopyrrolate is not metabolized by this enzyme, resulting in a more predictable and sustained effect.
Question 3: A 5-year-old male ferret with a suspected insulinoma is presented for an exploratory laparotomy. Which of the following pre-operative fasting recommendations is most appropriate to minimize anesthetic risk?
- Fast for 12 hours to ensure an empty stomach, similar to a cat.
- Fast for 8 hours but allow access to a high-sugar supplement like corn syrup.
- Do not fast the ferret at all to prevent a hypoglycemic crisis.
- Fast for a short period of 2-4 hours to reduce the risk of regurgitation while minimizing the risk of severe hypoglycemia. (Correct answer)
Correct answer: Fast for a short period of 2-4 hours to reduce the risk of regurgitation while minimizing the risk of severe hypoglycemia.
Ferrets have a very short gastrointestinal transit time (3-4 hours) and a high metabolic rate, making them prone to hypoglycemia. In a patient with an insulinoma, which causes excess insulin secretion, this risk is greatly amplified. A short fast of 2-4 hours is recommended as a compromise to prevent regurgitation under anesthesia without inducing a dangerous hypoglycemic episode.
Question 4: When preparing an anesthetic bath for koi using tricaine methanesulfonate (MS-222), what is the most critical step to ensure fish safety and reduce tissue irritation?
- Adding sodium bicarbonate to buffer the acidic solution. (Correct answer)
- Chilling the water to 5°C to potentiate the anesthetic effect.
- Using distilled water to ensure a pure solution.
- Mixing the MS-222 powder with a small amount of ethanol to aid dissolution.
Correct answer: Adding sodium bicarbonate to buffer the acidic solution.
Tricaine methanesulfonate (MS-222) is an acidic compound that significantly lowers the pH of water when dissolved. This acidic water is highly irritating to the gills and skin of fish and can cause metabolic acidosis. It is standard and essential practice to buffer the MS-222 solution with sodium bicarbonate to a neutral pH (7.0-7.5) before introducing the fish.
Question 5: A red-eared slider is induced for a shell fracture repair. Immediately following intravenous administration of an anesthetic agent, the turtle becomes profoundly apneic and bradycardic. Which physiological mechanism is the most likely cause of this response?
- Bezold-Jarisch reflex
- Cushing's reflex
- Diving reflex (Correct answer)
- Bainbridge reflex
Correct answer: Diving reflex
Aquatic and semi-aquatic reptiles, like the red-eared slider, possess a strong diving reflex. This reflex, which can be triggered by facial immersion, breath-holding, or certain anesthetic drugs, is characterized by intense bradycardia, apnea, and peripheral vasoconstriction, allowing them to conserve oxygen. Anesthetic induction can often stimulate this reflex.
Question 6: A veterinarian is deciding between alfaxalone and propofol for intramuscular (IM) induction of a bearded dragon that is difficult to handle. Which of the following is a key advantage of alfaxalone over propofol for this specific route of administration in a reptile?
- Alfaxalone provides significant postoperative analgesia, unlike propofol.
- Alfaxalone can be administered effectively via the IM route, whereas propofol is generally recommended for IV/IO use only. (Correct answer)
- Propofol causes severe hypertension in reptiles when given IM.
- Alfaxalone has a much shorter duration of action, allowing for faster recovery.
Correct answer: Alfaxalone can be administered effectively via the IM route, whereas propofol is generally recommended for IV/IO use only.
Alfaxalone can be administered effectively via the intramuscular (IM) route in reptiles, which is a significant advantage for fractious or small patients where intravenous access is difficult to obtain. Propofol, in contrast, is primarily an intravenous or intraosseous agent, and extravascular injection can be irritating and is not a reliable route for induction.
ICVA - International Council for Veterinary Assessment Exotic Animal Anesthesia Questions and Answers 1
A veterinarian is preparing to anesthetize a 12-year-old blue-and-gold macaw for a surgical procedure.
Which anatomical feature is most critical to consider when selecting and placing an endotracheal tube in this patient?