Small Animal Anesthesia Exam 2
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- What would the patient status classification be (relative to anesthetic risk) for a neonate?
- Class 2, Slight Risk
- What would the patient status classification be (relative to anesthetic risk) for a patient with severe preexisting systemic disease such as uncompensated heart disease?
- Class 5, Grave Risk
- What would the patient status classification be (Relative to anesthetic risk) for a six month old Labrador Retreiver with no underlying problems admitted to the hospital for an ovariohysterectomy?
- Class 1, Minimum risk
- What is the typical preanesthetic protocol for withholding food and water in a six month olf dog scheduled for an elective surgery such as an ovariohysterectomy?
- No food for 12 hours and water for 2 hours before surgery
- what is the typical preanesthetic protocol for withholding food and water in an otherwise healthy dog schedule for GI surgery?
- No food for 24 hours, and no water for 8-10 hours before surgery
- Give three examples of animals that are typically not fasted prior to anethesia. (4 listed pick 3)
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-dogs and cats under 3 months old
-Birds
-Rodents
-Rabbits - What is the typical IV fluid rate used in an uncomplicated surgical procedure on a patient with no underlying problems?
- 10 ml/kg/hr
- Would the typical IV fluid rate be higher or lower than normal in an animal with cardiac or repiratory disease?
- Lower
- Would the IV fluid rate be increased or decrease for an animal that became hypotensive during anesthesia/surgery?
- increase
- Give an example of an anticholinergic drug routinely used as a preanesthetic agent.
- Atropine (or glycopyrrolate)
- what two conditions/problems are prevented/treated by anticholinergic drugs?
- bradycardias and profuse salivation
- what is the most serious potential side effect of anticholinergic drugs?
- tachycardia
- what are two advantages of glycopyrrolate over atropine?
- less tendancy to cause tachycardia and cardiac arrhythmias and more effective at suppressing salivation
- What type of drug is acepromazine?
- a Phenothiazine tranquilizer
- What effect does acepromazine have on blood pressure?
- decreases it
- Why does acepromazine decrease blood pressure?
- Peripheral vasodilation is caused by Acepromazine (Alpha 1 blocker)
- In what breed of dog should acepromazine not be used?
- boxers
- which of the tranquilizer of sedative agents that we discussed would be most appropriate for use in an animal with a history of seizures? (either the catagory of agent or a specific example of this catagory)
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Catagory: Benzodiazepines
Drug: Diazapam (valium), Midazolam (versed), Lorzepam (ativan), zolazepam(+ Tiletamine = Telazol) - which of the tranquilizer or sedative agents that we discussed would be contraindicated in an animal with a history of seizures?
- acepromazine
- Which of the preanesthetic agents we discussed has the highest rate of anesthetic complications and death? Why?
- Xylazine, because of the profound cardiovascular effects and respiratory depression.
- what is the mode of action of xylazine?
- cause sedation, analgesia and muscle relaxation
- which of the categories of preanesthetic agents that we have discussed provides the most effective analgesia?
- Opiods
- What is the most potentially life threatening side effec of opiods?
- Respiratory depression
- which of the preanesthetic agents we discussed commonly causes vomiting as a side effect?
- xylazine
- why does medetomidine (Domitor) cause more potent sedation, muscle relaxation, and analgesia with less side effects then xylazine (rompun)?
- because it has 10x more affinity for alpha-2, but less affinity for alpha-1 receptors than xylazine
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What are the reversal agents for the following drugs?
A- Xylazine
B- Medetomidine
C- Oxymorphone -
A- Yohimbine (Yobine)
B- Medetomidine (Antisedan)
C- Naloxone - what is the primary beneficial effect of opioids? What is another reason for which opioids are used?
- analgesia and Sedation in dogs
- what is the most serious potential adverse side effect of opioid use in the peri-anesthetic period?
- Respiratory Depression
- In what species is an excitatory response frequently seen with intravenous administration of opioids?
- Cats
- Why do different opioids cause different effects in an animal?
- Opioids have different affinities for the different receptors and different species have different percentages of the different receptors.
- List two opioids that have mixed agonist/antagonist properties
- Butorphanol and buprenorphine
- Why might butorphanol and burenorphine (2 opioids that have mixed agonist/antagonist properties) be used instead of a pure antagonist to partially reverse a pure opioid agonist?
- to provide continued analgesia
- discuss the distribution and elimination of the thiobarbituate thiopental (pentothal) in the body after intravenous administration.
- it has a rapid diffusion into brain then rapid redistribution to fat/muscle then metabolized by liver and distributed to kidneys
- why is repeated dosing of the thiobarbituate thiopental (pentothal) not recommended?
- because they accumulate in the body and prolong recovery.
- give two reasons why sighthounds recover very slowly from thiobarbituates (and thus the ues of thiobarbituates in these animals is not recommended).
- they ahve minimal redistribution and decreased liver metabolism
- why do barbituates exhibit greater potency in animals that are hypoproteinemic?
- Barbituates are high protein bound, so if the animal has lowered protein it means tehre is more free drug in the system that gets to the brain.
- Why do barbituates exhibit greater potency in animals that are obese?
- Because the dosing is calculated for normal sized animals, using that dosing on an overweight animal means more drug is dosed than is being used in the animals system.
- what happens if thiopental is administered perivascularly?
- tissue sloughing, necrosis or irritation
- What effect do barbituates have on heart and respiratory function?
- transient arrythmias and respiratory depression
- why can methohexital be redosed without prolonging recovery time whereas thiopental can not?
- Methohexital is quickly cleared by the liver
- what are the two most common uses of pentobarbital in practice?
- Euthanasia and soemtimes to treat seizures
- what is the term used to characterize the type of anesthesia produced by ketamine or tiletamine?
- dissociative
- what effect do ketamine and tiletamine have on heart rate and blood pressure?
- increased heart rate and blood pressure
- what effect do ketamine and tiletamine have on respiration?
- shallow breaths with reduced respiratory rates
- what effect do ketamine and tiletamine have on most reflex activity?
- exaggerated relex responses
- give two reasons why diazepam is a good drug to administer concurrently with ketamine
- diazepam will cause muscle relaxation and it has an antiseizure effect
- what two drugs are in the combination product telazol?
- tiletamine and zolazepam
- what may be seen diruing recovery from telazol, particularly in dogs taht are given this product by IM administration?
- a prolonged recovery time (5 hours)
- what is neuroleptanalgesia?
- a state of profound sedation
- over what time span should propofol be given?
- 60-90 seconds and then titrated to effect
- what is the biggest disadvantage of propofol?
- It has poor storage.
- what complication is commonly associated with rapid intravenous administration of propofol?
- can depress respiration or cause apnea
- would an inhalation anesthetic agent with a high vapor pressure be expected to require a precision vaporizer or a non-precision vaporizer?
- precision vaporizer because high vapor pressure is volatile and evaporates easily and if not controlled can be lethal.
- would an inhalation anesthetic with a low blood to gas solubility coefficient be expected to have rapid or slow induction and recovery?
- rapid induction and recovery because it diffuses into alveoli and creates steep concentration gradient which means it diffuses in and out of the brain quickly.
- place the following in order from lowest blood to gas solubility coefficient to highest: Isoflurane, Methoxyflurane, Sevoflurane, Haloflurane
- Isoflurane, Sevoflurane, halothane, methoxyflurane
- which inhalant anesthetic gas undergoes the most rapid induction and recovery?
- Isoflurane.
- Place the following in order form lowest to highest MAC (min alveolar concentration): Isoflurane, Methoxyflurane, Halothane, Sevoflurane
- Methoxyflurane, halothane, sevoflurane, isoflurane
- which of the inhalant anesthetic agents is the most potent?
- Methoxyflurane
- which inhalation anesthetic agent is associated with sensitizing the heart to epinephrine induced arrhythmias and malignany hyperthermia?
- Halothane
- which twoinhalation anesthetics have the fewest adverse side effects on the heart and other vital systems?
- isoflurane and sevoflurane
- Which inhalation anesthetic requires tne least metabolism by the liver?
- Isoflurane.
- which inhalation anesthetic requires the most metabolism by the liver?
- methoxyflurane
- which inhalation anesthetic produces a significant analgesic effect?
- methoxyflurane.
- which inhalation anesthetic produces muscle relaxation?
- isoflurane
- What is the disadvantage of an inhalation anesthetic with a high rubber solubility coefficient?
- Anesthetic gets stuck in the tubing, and therefor the patient isn't getting all anesthetic it needs, and once done, anesthetic continues to be released from the rubber and into the room.
- why is enflurane not commonly used in veterinary medicine?
- because it causes profound respiratory depression and muscle hyperactivity.
- why is desflurane not commonly used in veterinary medicine?
- because it is very expensive.
- What is doxapram
- a respiratory stimulant.
- why is nitrous oxide not useful as a sole anesthetic agent in dogs and cats?
- it cannot attain a surgical plane alone.
- why does the risk of hypoxia increase when nitrous oxide is used in a protocol for inhalation anesthesia?
- it limits the amount of oxygen delivered to the patient.
- why can diffusion hypoxia occur during recovery when nitrous oxide is used in protocol for inhalation anesthesia?
- N2O2 rapidly diffuses from body displacing O2 in alveoli.
- what do we mean when we say that a drug should be titrated to effect?
- use a small amount until desired effect is acheived.
- Why are sedatives commonly used as preanesthetic drugs?
- smoother induction and recovery and allows a smaller dose of induction agent.
- what stage and plane ofgeneral anesthesia provides a medium depth of anesthesia suitable for surgery?
- Stage 3 Plane 2
- What stage and plane of general anesthesia provides a light depth of anesthesia suitable for endotracheal intubation?
- Stage 3 Plane 1
- what two things can be done to minimize Stage 2 of general anesthesia?
- use preanesthetic drugs and rapid induction rates
- Why do we want to minimize stage 2 of general anesthesia?
- because there is an excitement period where irregular breathing and exaggerated reflexes occur.
- At what stage and plane of general anesthesia is eyeball position ventral, pupils normal to partially constricted and PLR normal to mildly decreased?
- Stage 3 plane 1
- at what stage and plane of general anesthesia is eyeball position ventral (sometimes central), pupils slightly dilated and PLR sluggish?
- Stage 3 Plane 2
- At what stage and plane of general anesthesia is there grave danger of erspiratory and cardiac arrest?
- Stage 3 Plane 4
- What anesthetic agent is sometimes squirtedinto the mouth of vicious cats?
- Ketamine (Telazol)
- what is one adbantage of inducing a patient with an inhalation agent administered via a mask versus via an injectable agent?
- its good with fast acting inhalants
- what is one disadvantage of inducing a patient with an inhalation agent administered via a mask versus induction via an injectable agent?
- significant operating room pollution
- what is one advantage of inducing a patient with an inhalation agent administered via an induction chamber versus an injectable agent?
- can do on animals that are hard to handle.
- What is one disadvantage of inducing a patient with an inhalation agent administered via an induction chamber versus an injectable agent?
- it can only be done on smaller animals.
- what are three advantages to endotracheal intubation for general anesthesia?
- efficient delivery of gas to animal, reduce risk of aspiration and improves efficiency of respiration by decreasing dead space.
- what are three disadvantages to endotracheal intubation for general anesthesia?
- Stimulates the vagus nerve, it can be hard to intubate brachycephalic animals and it can damage and larynx, pharynx and soft palate.