NAVLE Veterinary Anesthesia and Pain Management 4 — Questions and Answers
Question 1: A 6-year-old Labrador is undergoing a splenectomy under isoflurane anesthesia. The end-tidal CO2 rises to 65 mmHg. What is the most appropriate initial intervention?
- Increase fresh gas flow rate
- Increase respiratory rate on the ventilator (Correct answer)
- Switch to sevoflurane
- Administer sodium bicarbonate IV
Correct answer: Increase respiratory rate on the ventilator
Increasing the ventilator rate will increase minute ventilation and eliminate the excess CO2, correcting the hypercapnia.
Question 2: Which opioid is most appropriate for epidural administration in dogs to provide extended postoperative analgesia with minimal motor blockade?
- Fentanyl
- Meperidine
- Morphine (Correct answer)
- Butorphanol
Correct answer: Morphine
Preservative-free morphine administered epidurally provides long-duration analgesia (12–24 hours) with minimal motor effects due to its hydrophilicity.
Question 3: A cat anesthetized with ketamine/diazepam develops prolonged apnea after induction. Which characteristic of ketamine best explains this risk?
- Ketamine stimulates mu-opioid receptors
- Ketamine causes dose-dependent respiratory depression at high doses (Correct answer)
- Ketamine inhibits NMDA receptors in the brainstem
- Ketamine increases upper airway secretions causing obstruction
Correct answer: Ketamine causes dose-dependent respiratory depression at high doses
While ketamine is generally considered a respiratory-sparing agent, high or rapidly administered doses can cause dose-dependent apnea in cats.
Question 4: During anesthesia of a horse, you notice the mean arterial pressure drops to 55 mmHg. After adjusting vaporizer settings, which drug is most appropriate to improve cardiac output?
- Atropine
- Dobutamine (Correct answer)
- Epinephrine
- Vasopressin
Correct answer: Dobutamine
Dobutamine is a positive inotrope that increases cardiac output and improves perfusion pressure in anesthetized horses with inhalant-induced hypotension.
Question 5: A ferret presents for adrenalectomy. Which induction agent combination is most commonly used in ferrets for short procedures?
- Propofol alone IV
- Ketamine and midazolam IM (Correct answer)
- Alfaxalone and diazepam IM
- Tiletamine-zolazepam IM
Correct answer: Ketamine and midazolam IM
Ketamine combined with midazolam (or diazepam) given IM is a practical and commonly used induction protocol in ferrets, providing smooth anesthesia.
Question 6: Which local anesthetic has the highest risk of causing methemoglobinemia in cats?
- Bupivacaine
- Lidocaine
- Benzocaine (Correct answer)
- Ropivacaine
Correct answer: Benzocaine
Benzocaine, found in some topical sprays, rapidly induces methemoglobinemia in cats due to their limited ability to metabolize certain oxidizing agents.
Question 7: A dog receives acepromazine premedication followed by isoflurane anesthesia. It develops refractory hypotension unresponsive to fluids. Which vasopressor is most appropriate?
- Dopamine at 2 mcg/kg/min
- Norepinephrine CRI
- Phenylephrine bolus
- Ephedrine IV bolus (Correct answer)
Correct answer: Ephedrine IV bolus
Ephedrine has both alpha and beta agonist activity and is effective for treating hypotension caused by vasodilation from acepromazine plus inhalant anesthesia.
NAVLE Veterinary Anesthesia and Pain Management 4
A 6-year-old Labrador is undergoing a splenectomy under isoflurane anesthesia.
The end-tidal CO2 rises to 65 mmHg.
What is the most appropriate initial intervention?