DM1 Pt4-4 Injectable Agents Flashcards
What are the main injectable agents used for maintenance of anesthesia?
Propofol, alfaxalone, and ketamine are the main injectable agents used for maintaining anesthesia.
Why is continuous rate infusion (CRI) preferred over bolus technique for maintenance of anesthesia?
CRI allows for a more stable plane of anesthesia and reduces the total drug dose required, lowering the risk of side effects and drug accumulation.
Why are high doses of propofol or alfaxalone required without other analgesic agents?
Neither propofol nor alfaxalone have analgesic properties, so high doses are needed to prevent movement or autonomic responses to surgical stimulation unless used in combination with an analgesic agent.
What is a key disadvantage of prolonged propofol use in cats?
Cats have a reduced ability to metabolize phenolic compounds like propofol, leading to drug accumulation and prolonged recovery times when used for more than 20-30 minutes.
For what procedures might total intravenous anesthesia (TIVA) be selected over volatile agents?
TIVA is often used for procedures like bronchoscopy, tracheal foreign body removal, and esophageal foreign body removal where intubation may not be practical or extubation may be needed during the procedure.
How does ketamine provide maintenance of anesthesia?
Ketamine is used either intravenously (usually as part of a low-dose CRI for analgesia) or intramuscularly, often in combination with other agents like medetomidine and butorphanol, to provide maintenance of anesthesia.
Why is ketamine often combined with other agents for maintenance of anesthesia?
Ketamine is a poor muscle relaxant and can cause CNS excitation during recovery, so it is usually combined with other agents to ensure muscle relaxation and reduce the required dose, minimizing CNS side effects during recovery.
What is the triple combination for maintenance of anesthesia in cats?
The triple combination includes ketamine, medetomidine, and butorphanol (or buprenorphine) and is used to induce and maintain anesthesia for minor procedures, providing around 20 minutes of surgical anesthesia.
When should intubation be considered when using the triple combination in cats?
Intubation should be considered based on the duration of the procedure, the surgeon’s experience, and patient characteristics. Brachycephalic cats or those undergoing longer procedures may require intubation to ensure airway patency and oxygen supplementation.
What is the advantage of substituting buprenorphine for butorphanol in the triple combination?
Buprenorphine provides more efficacious and longer-lasting analgesia (6 hours compared to 90 minutes for butorphanol).
Why should at least 30 minutes elapse after ketamine administration before antagonizing alpha-2 agonists?
Waiting 30 minutes before administering atipamezole (alpha-2 antagonist) prevents unmasking of the CNS effects of ketamine, which could result in a disoriented, “spacey” recovery if sedation from the alpha-2 agonist is reversed too soon.
What is the quad protocol for early neutering of kittens?
The quad protocol includes medetomidine, ketamine, midazolam, and buprenorphine, providing short-duration anesthesia and analgesia adequate for neutering kittens under 6 weeks of age. Oxygen is usually supplemented via face mask due to difficulty with intubation in small kittens.
