Classification of Anesthetic Agents & Adjuncts

These flashcards cover key concepts related to the classification and use of anesthetic agents, their pharmacology, and important monitoring practices during anesthesia.

What are the main ways anesthetic agents and adjuncts are classified?

By route of administration, time of administration, principal effect, and chemistry.

What two pharmacologic concepts are important for anesthetic agents?

Pharmacokinetics and pharmacodynamics.

What is an agonist?

A drug that binds to and stimulates the target tissue.

What is an antagonist?

A drug that binds to the target tissue but does not stimulate it.

What are partial agonists?

Drugs that partially stimulate receptors or block pure agonists.

Are most general anesthetics analgesics?

No, true analgesics must be provided separately pre- and postoperatively.

What precautions should be taken when combining drugs?

Only mix if compatible and do not use if a precipitate forms.

How are controlled substances regulated in the U.S.?

By the Controlled Substances Act (DEA).

How often must controlled substance inventory be done in veterinary medicine?

Every 2 years.

How are Schedule II drugs ordered?

Using DEA Form 222 in the U.S.

How should controlled substances be stored?

In a securely locked cabinet; opioids in a safe or steel cabinet.

What are the purposes of preanesthetic medications?

To calm/sedate the animal, minimize adverse effects, reduce drug doses, ensure smooth induction/recovery, and provide analgesia.

How does the route of administration affect preanesthetic medications?

SC: slowest onset, IM: faster onset, IV: fastest onset.

What are the main anticholinergics used in preanesthesia?

Atropine and glycopyrrolate.

What effects do anticholinergics have?

Prevent bradycardia, decrease secretions, induce mydriasis and bronchodilation.

What are the major classes of tranquilizers/sedatives?

Phenothiazines, benzodiazepines, alpha2-adrenoceptor agonists, and alpha2-antagonists.

What is acpromazine used for?

Preanesthetic sedation and to reduce general anesthetic dosage.

What are the key benzodiazepines?

Diazepam, midazolam, and zolazepam.

What are some effects of alpha2-agonists?

Sedation, analgesia, muscle relaxation, bradycardia.

What classifications exist for opioids?

Agonists, partial agonists, agonist-antagonists, and antagonists.

What is neuroleptanalgesia?

Profound sedation and analgesia from a simultaneous opioid and tranquilizer.

What are some common injectable anesthetics?

Propofol, etomidate, alfaxalone, barbiturates.

What is the best indicator of patient wellbeing under anesthesia?

Vital signs.

How many stages of anesthesia are there?

Four stages.

What characterizes Stage I of anesthesia?

Voluntary movement, fear, excitement, ending with recumbency.

What is the goal of surgical anesthesia?

To ensure the patient doesn’t move, isn’t aware, feels no pain, and has no memory of the procedure.

What is capillary refill time (CRT) and its significance?

Time for color to return to mucous membranes after pressure; >2s indicates poor perfusion.

What does blood pressure indicate during anesthesia?

Tissue perfusion.

What is normal SaO2 in an anesthetized patient breathing oxygen?

95%.

What does a pulse oximeter measure?

Hemoglobin oxygen saturation and heart rate.

What is local anesthesia?

Use of a chemical agent to block sensation in a specific area without affecting consciousness.

What is an epidural anesthesia?

Injection into the epidural space to block sensation/motor control of the rear, abdomen, pelvis, and limbs.

What is assisted ventilation?

Patient initiates breaths while the anesthetist helps.

What are neuromuscular blocking agents (NMBAs)?

Muscle-paralyzing agents used with controlled ventilation that do not provide anesthesia or analgesia alone.

What are some adverse effects of local anesthesia?

Motor loss, tissue irritation, paresthesia, allergic reactions, systemic toxicity.