Anesthesia Techniques for Veterinary Medicine

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Questions and Answers

What is the effect of delaying cardiac compressions during a cardiac arrest under general anesthesia?

Unnecessarily complicates the procedure

Improves recovery chances

Worsens recovery chances (correct)

Has no effect on outcomes

What type of anesthetic circuit is a Bain system when operated at ~300 ml/kg/min flow rate?

Open system

Partial rebreathing

Nonrebreathing (correct)

Closed system

In what position are dogs typically intubated?

Sternal recumbency (correct)

Standing position

Sitting position

Dorsal recumbency

Which type of breathing system operates at flow rates of approximately 10-30 ml/kg/min?

Semi-closed system Signup and view all the answers

What is true about the flow rate in a closed anesthetic rebreathing system?

It only meets metabolic needs with low flow Signup and view all the answers

What additional presence has been shown to improve outcomes during a cardiac arrest?

Anesthesia monitors constantly evaluating cardiovascular function Signup and view all the answers

At moderate flow rates of ~20-300 ml/kg/min, how does the Bain system function?

As a semi-closed or partial rebreathing system Signup and view all the answers

What position are horses typically intubated in due to their size?

Lateral recumbency Signup and view all the answers

What is the primary benefit of using a scavenger system in anesthetic procedures?

To eliminate exhaled waste anesthetic gases Signup and view all the answers

What does the minimum alveolar concentration (MAC) specifically measure?

Measure of anesthetic potency Signup and view all the answers

Why is it important to change charcoal absorbers in a scavenger system?

They lose effectiveness after a certain weight gain Signup and view all the answers

Which of the following statements about Propofol is accurate?

It is rapidly cleared from the body Signup and view all the answers

What happens if Propofol is administered too quickly?

Can lead to apnea or respiratory arrest Signup and view all the answers

What is the recommended action after opening a vial of Propofol?

It must be discarded within one hour Signup and view all the answers

What does OSHA cover in relation to anesthetic gases?

Management of waste anesthetic gases Signup and view all the answers

What is a key effect of using multiples of the MAC value during anesthesia?

It guarantees complete anesthesia during the procedure Signup and view all the answers

What are the primary effects of acepromazine in dogs and cats?

Anti-emesis, vasodilation Signup and view all the answers

Why are atropine or glycopyrrolate typically administered before anesthesia induction?

Decreases salivation Signup and view all the answers

What effect does acepromazine NOT have on the body?

Provides analgesia Signup and view all the answers

Which system does a low-pressure check on an anesthetic machine monitor for leaks?

In the breathing circuit Signup and view all the answers

What is one of the mechanisms of action of acepromazine?

Blocks peripheral alpha-1 receptors Signup and view all the answers

What cardiovascular effect do anti-cholinergics like atropine have?

They increase heart rate Signup and view all the answers

What is a side effect of using dissociative anesthetics such as ketamine?

Enhancement of salivation Signup and view all the answers

What effect is NOT produced by acepromazine on the central nervous system?

Analgesia Signup and view all the answers

What is the final step in the transfer of a painful stimulus?

Perception Signup and view all the answers

Which process occurs first when experiencing pain?

Transduction Signup and view all the answers

What role does modulation play in pain signaling?

Amplifies or suppresses the signal Signup and view all the answers

What is the primary use of xylazine in cattle?

Chemical restraint Signup and view all the answers

What can help prevent laryngospasm in cats during anesthesia induction?

1-2% Lidocaine spray Signup and view all the answers

Why is xylazine usage in cattle a concern at high doses?

It can lead to bloat and hypoxemia Signup and view all the answers

What is a common characteristic of nociceptors?

They are found on nerve endings Signup and view all the answers

What is the correct order of events in pain pathway activation?

Transduction, Transmission, Modulation, Perception Signup and view all the answers

Which inhalant anesthetic has the lowest MAC in dogs?

Isoflurane Signup and view all the answers

What is the MAC value for Sevoflurane in cats?

2.58 Signup and view all the answers

Which inhalant anesthetic requires a greater percentage for administration due to lower solubility?

Desflurane Signup and view all the answers

What is the normal capnography reading for a patient under inhalant anesthesia?

40-55 mm Hg Signup and view all the answers

Which sedative is known to cause the least cardiac and respiratory depression?

Acepromazine Signup and view all the answers

Which inhalant anesthetic has the highest MAC in cats?

Desflurane Signup and view all the answers

What happens to alveolar levels of anesthetic when the vaporizer is turned off?

They drop rapidly Signup and view all the answers

How does the solubility of an inhalant anesthetic affect patient recovery time?

Less soluble drugs result in faster recovery Signup and view all the answers

Study Notes

Anesthetic Breathing Circuits

A Bain system run at a high flow rate (~300 ml/kg/min) is a nonrebreathing system
At moderate flow rates (~20-300 ml/kg/min) the Bain system functions as a partial rebreathing system
Semi-closed and partial rebreathing systems are the same, running at intermediate flow rates (10 ml/kg/min for large animals to 30 ml/kg/min for small animals).
Closed anesthetic rebreathing systems have a low fresh gas flow rate of ~5-10 ml/kg/min (lower for larger animals, higher for smaller animals).

Intubation

Dogs, cats, and small ruminants are typically intubated in sternal recumbency
Horses are intubated in lateral recumbency

Endotracheal Tube Placement Confirmation

Proper endotracheal tube placement can be confirmed by using a scavenger system

Minimum Alveolar Concentration (MAC)

MAC is a measure of anesthetic potency
It's the minimum concentration of anesthetic in the alveolar gas that prevents a physical response in 50% of animals exposed to a surgical stimulus
Most anesthetics require multiples of MAC to guarantee appropriate anesthesia during surgery

Propofol

Propofol is a non-barbiturate anesthetic agent
It provides minimal to no analgesic effects
Propofol without preservatives should be discarded within six hours of opening
Propofol-28 can be used for 28 days after opening
Propofol is rapidly cleared from the body
It can cause apnea (breathing stops) if given too rapidly

MAC for Inhalant Anesthetics

Isoflurane has the lowest MAC (1.2 in dogs, 1.63 in cats, 1.31 in horses)
Sevoflurane has an intermediate MAC (2.1 in dogs, 2.58 in cats, 2.31 in horses)
Desflurane has the highest MAC (7.2 in dogs, 9.8 in cats, 7.6 in horses)
Inhalants with high potency have lower MACs and higher blood & tissue solubility
Higher solubility drugs achieve equilibrium faster, leading to faster induction and recovery.

Capnography

Capnography measures the amount of expired carbon dioxide (CO2) in each breath
This is commonly called "end-tidal CO2"
Normal capnography reading under inhalant anesthesia is 40-55 mm Hg
Higher CO2 levels indicate hypoxia
Lower levels indicate hyperventilation

Acepromazine

Acepromazine causes minimal respiratory and cardiac depression
It is a phenothiazine tranquilizer that causes mild sedation
It causes vasodilation and acts as an anti-emetic, sedative, muscle relaxant, and anti-arrhythmic
Acepromazine does NOT provide analgesia or cause vasoconstriction
It blocks peripheral alpha-1 receptors and dopamine receptors in the brain

Atropine & Glycopyrrolate (Anti-cholinergics)

Anti-cholinergics are given as pre-meds to decrease salivation, decrease airway secretions, and increase heart rate
They do not affect eye closure, but they do dilate the pupils

Laryngospasm Prevention

You can prevent laryngospasm in cats during induction and maintenance of anesthesia by spraying the larynx with 1-2% lidocaine

Xylazine

Xylazine is primarily used for chemical restraint in cattle
It has sedative, analgesic, and muscle relaxation properties
Cattle are very sensitive to xylazine
It is often used in combination with ketamine and butorphanol
Xylazine can cause bloat and hypoxemia in cattle
It is reversed with yohimbine, atipamezole, or tolazoline

Pain Physiology

Perception is the final step in pain transmission
Transduction of the stimulus occurs by pain receptors (nociceptors)
Transmission to the dorsal horn of the spinal cord
Modulation of the signal in the spinal cord and brain
Projection to the brain
Perception in the cerebral cortex

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Description

This quiz covers anesthetic breathing circuits, intubation techniques, and confirmation of endotracheal tube placement in veterinary practice. It also discusses Minimum Alveolar Concentration (MAC) and its significance in dosing anesthetics for animals. Test your knowledge on these critical veterinary anesthesia concepts.