Anesthesia/Pre-Anesthetics Flashcards
What is anesthesia? What is it used in veterinary medicine to provide?
state of controlled, temporary loss of sensation or awareness induced for medical purposes
- sedation
- tranquilization
- immobility
- muscle relaxation
- unconciousness
- pain control
during surgery, dentistry, grooming, diagnostic imaging, wound care, and capture/transport of wildlife
Conscious vs. unconscious:
What’s the difference between local, regional, and general anesthesia?
LOCAL: numbs a small section of the body, commonly during cataract surgery, dental procedures, or skin biopsies where the patient remains awake
REGIONAL: blocks pain in a larger part of the body, commonly during epidurals, spinal/hip/knee durgery, or an arm block for hand surgery, where the patient remains awake or have some sedation
GENERAL: unconscious and insensitive to pain or other stimuli, commonly used for invasive surgeries on the head, chest, or abdomen
What is sedation?
relaxation to the point where the patient can be easily aroused or awakened
What are the 4 stages of anesthesia?
STAGE I: analgesia without amnesia
STAGE II: excitement, nausea, vomiting, hyperreactivity, irregular respiration —> goal is to move through this stage as rapidly as possible
STAGE III: surgical anesthesia, sleep, normal respiration and blood pressure, muscle relaxation, complete loss of pain sensation
STAGE IV: medullary depression of vasomotor and respiratory centers causing coma and death (overdose)
Why are adjuncts used with anesthesia?
produces other desired effects, such as desation, muscle relaxation, analgesia, reversal, neuromuscular blockade, or parasympathetic blockade
- tranquilizers
- opioids
What are pre-anesthetic medications? What are 4 common uses?
medications used prior to the administration of an anesthetic agent to make anesthesia safe and more agreeable to the patient
- sedation to reduce anxiety and apprehension
- obtain an additive or synergistic effect so that induction can be smooth and rapid
- counteract certain adverse effects of anesthetics
- relieve from pain
How does the route of administration affect drug onset and duration?
SC: slowest onset, longest duration
IM: faster onset, shorter duration
IV: fastest onset, shortest duration
What are the 6 effects of pre-anesthetic medications and adjuncts?
- calm and sedate excited animals
- minimize adverse drug effects
- reduce dose of concurrent drugs
- smoother anesthetic induction and recovery
- analgesia
- muscle relaxation
What 4 drug classifications are commonly used as pre-anesthetics and adjuncts? What do they do?
- opioids - analgesia
- tranquilizers - pre-operative sedation and amnesia; prevent or counteract CNS stimulation caused by some anesthetics
- central muscle relaxants - muscle relaxation during anesthesia
- anticholinergic agents - prevent profuse salivation and bradycardia
What are the 3 most common drugs used as pre-anesthetics and adjuncts? 3 additional?
- opioids - Morphine
- phenothiazine tranquilizers - Acepromazine
- benzodiazepeines - Diazepam
- α2-agonists - Xylazine
- anticholinergics - Atropine
- muscle relaxants - Baclofen
Why do we use analgesics as a pre-anesthetic?
most general anesthetics are not analgesics - patient will feel pain after surgery
(true analgesics don’t provide general anesthesia)
How are opioids used as a pre-anesthetic? What 2 are most commonly used?
perioperative analgesia
- Morphine - safe, effective for mild and severe pain
- Butorphanol (+++κ, μ) - keeps analgesia, reverses sedation, respiratory depression
(can be used in combination with tranquilizers and anticholinergics)
What is an additional benefit of Morphine as a pre-anesthetic?
good sedative for dogs
How are tranquilizers used as pre-anesthetics? Which one is most commonly used?
reduces anxiety, calms, and enhances CNS depressant and analgesic effects of other anesthetics
Acepromazine