Anesthesia and Pain Management Flashcards

A 6-year-old English Bulldog is scheduled for a soft palate resection. Which of the following is the most critical consideration during the anesthetic management of this patient?

Answer: Prioritizing pre-oxygenation before induction and ensuring rapid control of the airway via endotracheal intubation.

Brachycephalic breeds, like English Bulldogs, have compromised airways (stenotic nares, elongated soft palate), making induction and recovery the most dangerous periods of anesthesia. Pre-oxygenation increases the body's oxygen reserves, providing a crucial safety margin during the induction period when the patient may become apneic. Securing the airway quickly with an endotracheal tube is paramount to maintain a patent airway and ensure adequate ventilation and oxygenation.

A veterinarian is planning to use gabapentin as part of a multi-modal analgesic plan for a dog with chronic neuropathic pain. What is the primary mechanism of action for gabapentin's analgesic effect?

Answer: It binds to a subunit of voltage-gated calcium channels, reducing the release of excitatory neurotransmitters.

Although structurally similar to the neurotransmitter GABA, gabapentin does not bind to GABA receptors or influence GABA metabolism. Its primary analgesic effect is achieved by binding to the alpha-2-delta subunit of presynaptic voltage-gated calcium channels in the central nervous system. This action inhibits the influx of calcium, which in turn decreases the release of excitatory neurotransmitters like glutamate and substance P that are involved in pain signal transmission.

Which of the following statements most accurately describes the clinical use of tramadol for analgesia in dogs versus cats?

Answer: Tramadol is a more reliable oral analgesic in cats because they produce higher levels of the active metabolite (O-desmethyltramadol) compared to dogs.

The analgesic efficacy of tramadol relies heavily on its metabolism to O-desmethyltramadol (M1), which has a much higher affinity for mu-opioid receptors. Cats metabolize tramadol effectively, producing significant amounts of the active M1 metabolite, which contributes to its analgesic effect. Dogs, in contrast, produce very little M1 and primarily produce the inactive N-desmethyl tramadol metabolite, making the opioid effect of tramadol questionable and less reliable in this species.

During a dental procedure on a 4 kg cat, a continuous rate infusion of lidocaine is administered. The technician performing the monitoring suddenly notes muscle tremors, salivation, and vomiting. These are most likely clinical signs of:

Answer: Local anesthetic toxicity.

Cats are particularly sensitive to the toxic effects of local anesthetics like lidocaine. The clinical signs of toxicity primarily involve the central nervous system (CNS) and can progress from initial signs like muscle tremors, twitching, and salivation to more severe signs like seizures, coma, and respiratory arrest. Vomiting is also a potential sign.

The Minimum Alveolar Concentration (MAC) of an inhalant anesthetic is a measure of its potency. The approximate MAC of sevoflurane in a healthy, adult dog is:

Answer: 2.4%

The Minimum Alveolar Concentration (MAC) is the concentration of an anesthetic in the alveoli of the lungs that is needed to prevent movement in 50% of subjects in response to a noxious stimulus. For sevoflurane in dogs, the established MAC is approximately 2.36%, often rounded to 2.4%. This value is a standard measure of anesthetic potency used to guide anesthetic administration.

A veterinarian administers dexmedetomidine to a healthy adult horse for sedation prior to a standing procedure. Which of the following sets of physiological effects is most expected?

Answer: Bradycardia, initial hypertension followed by potential hypotension, and decreased GI motility.

Alpha-2 agonists like dexmedetomidine cause peripheral vasoconstriction, leading to an initial hypertension, which triggers a reflex bradycardia. As the drug's central effects take hold, cardiac output can decrease, potentially leading to hypotension. These drugs are also well-known for significantly reducing gastrointestinal motility and secretions. They inhibit insulin release, which can cause hyperglycemia, and inhibit antidiuretic hormone (ADH), causing diuresis.