Chapter 18 - Balanced Inhalation Anesthesia Flashcards
What is the minimum alveolar concentration (MAC) of isoflurane?
A) 0.88% B) 1.31% C) 2.31% D) 7.6%
B) 1.31%
What percentage of halothane is metabolized by the liver?
A) 0.2% B) 3% C) 5% D) 10%
A) 0.2%
Which inhalation anesthetic has the highest MAC?
A) Isoflurane B) Sevoflurane C) Desflurane D) Halothane
C) Desflurane
What is the typical dose range for lidocaine as a loading dose in horses?
A) 0.1–0.5 mg/kg B) 0.65–2 mg/kg C) 2–4 mg/kg D) 5–10 mg/kg
B) 0.65–2 mg/kg
How much does a CRI of medetomidine reduce MAC during anesthesia with sevoflurane?
A) 15% B) 28% C) 53% D) 70%
C) 53%
What is the duration range of anesthesia in the retrospective study involving medetomidine?
A) 20–60 minutes B) 40–420 minutes C) 60–120 minutes D) 90–180 minutes
B) 40–420 minutes
What is the infusion rate of dexmedetomidine that reduces MAC by 30%?
A) 1.75 μg/kg/h B) 3.5 μg/kg/h C) 5 μg/kg/h D) 10 μg/kg/h
A) 1.75 μg/kg/h
What is the average percentage of lidocaine that reduces MAC of halothane?
A) ≤20% B) 25% C) 50% to 70% D) 80%
C) 50% to 70%
How long before the end of surgery should lidocaine CRI be discontinued?
A) 10 minutes B) 20 minutes C) 30 minutes D) 60 minutes
C) 30 minutes
What percentage of sevoflurane MAC reduction is achieved with a loading dose of lidocaine?
A) 10% B) 25% C) 27% D) 50%
C) 27%
What is the fatality rate risk increase for horses undergoing emergency surgery?
A) 1.5-fold B) 2-fold C) Several-fold D) 10-fold
C) Several-fold
What is the primary reason for fatalities in horses undergoing modern inhalant anesthesia?
A) Cardiac arrest B) Fractures during recovery C) Anesthetic overdose D) Respiratory failure
B) Fractures during recovery
What type of molecule is isoflurane classified as?
A) Analgesic B) Inhalation anesthetic C) Opioid D) Local anesthetic
B) Inhalation anesthetic
What is the recommended infusion rate for lidocaine during CRI?
A) 10 μg/kg/min B) 25–50 μg/kg/min C) 100 μg/kg/min D) 150 μg/kg/min
B) 25–50 μg/kg/min
What is the effect of α2-adrenoreceptor agonists on the MAC of inhalation agents?
A) Increases MAC B) Decreases MAC C) No effect on MAC D) MAC is halved
B) Decreases MAC
What is the typical half-life of medetomidine?
A) 10 minutes B) 20 minutes C) 30 minutes D) Varies widely
D) Varies widely
What is the blood gas solubility characteristic of modern inhalation anesthetics?
A) Highly soluble B) Low solubility C) Moderate solubility D) Variable solubility
B) Low solubility
Which inhalation anesthetic has the lowest MAC value?
A) Isoflurane B) Sevoflurane C) Desflurane D) Halothane
D) Halothane
How much does desflurane reduce cardiac output at 1 MAC?
A) No effect B) 10% decrease C) 20% decrease D) 50% decrease
A) No effect
What is the common outcome when lidocaine is administered during anesthesia?
A) Increased MAC B) Enhanced cardiovascular function C) Reduced volatile agent requirements D) Prolonged recovery time
C) Reduced volatile agent requirements
What is the typical loading dose of lidocaine for effective plasma levels?
A) 0.5 mg/kg B) 1.0 mg/kg C) 1.3 mg/kg D) 2.0 mg/kg
C) 1.3 mg/kg
What is the effect of lidocaine on intestinal motility?
A) Decreases motility B) Increases motility C) No effect D) Variable effects
B) Increases motility
What should be monitored when administering α2-adrenoreceptor agonists?
A) Urine production B) Blood glucose C) Electrolytes D) Temperature
A) Urine production
for how long can negatively effect the cardiopulmonary function alpha2-adrenoreceptor agonist?
20 to120 minutes
Which α2-adrenoreceptor agonist is commonly used in equine anesthesia?
A) Romifidine B) Xylazine C) Detomidine D) All of the above
D) All of the above
What percentage of horses showed improved recovery quality with medetomidine compared to lidocaine?
A) 10% B) 25% C) 30% D) Better recovery with medetomidine
D) Better recovery with medetomidine
What is the consequence of using a bolus of medetomidine in standing horses?
A) Longer anesthesia time B) Minimal impact on heart rate C) Significant drop in blood pressure D) Increased heart rate
B) Minimal impact on heart rate
Which modern inhalation anesthetic is characterized by rapid uptake in young animals?
A) Halothane B) Isoflurane C) Sevoflurane D) Desflurane
D) Desflurane
What is the recommended CRI rate for dexmedetomidine?
A) 1 μg/kg/h B) 3.5 μg/kg/h C) 5 μg/kg/h D) 10 μg/kg/h
B) 3.5 μg/kg/h
In a clinical study, which anesthetic combination resulted in higher cardiac index?
A) Lidocaine/isoflurane B) Medetomidine/isoflurane C) Dexmedetomidine/sevoflurane D) Romifidine/halothane
A) Lidocaine/isoflurane
What is the common usage of urinary catheters in α2-adrenoreceptor agonist anesthesia?
A) To reduce infection risk B) To manage increased urine output C) For ease of monitoring D) To prevent urinary retention
B) To manage increased urine output
What is the effect of halothane on cardiac output?
A) Minimal effect B) Significant depression C) Increased output D) Variable effects
B) Significant depression
What is the potential risk with using high-dose lidocaine in compromised patients?
A) Cardiac arrest B) Toxicity C) Delayed recovery D) Increased MAC
B) Toxicity
How does recovery quality differ between medetomidine and lidocaine?
A) Medetomidine provides worse recovery B) Lidocaine provides better recovery C) Medetomidine provides better recovery D) No difference in recovery
C) Medetomidine provides better recovery
What is the key advantage of using modern inhalation anesthetics over halothane?
A) Higher potency B) Lower blood gas solubility C) Increased metabolic rate D) Higher toxicity
B) Lower blood gas solubility
How much does sevoflurane MAC reduce when lidocaine is used?
A) 10% B) 15% C) 25% D) 27%
D) 27%
What is the overall aim of balanced anesthesia techniques in horses?
A) Faster recovery B) Reduced surgical time C) Minimized perianesthetic complications D) Increased depth of anesthesia
C) Minimized perianesthetic complications
Which combination provides a better quality of recovery than lidocaine?
A) Ketamine B) Medetomidine C) Xylazine D) All of the above
B) Medetomidine
What is the recommended dosage for romifidine in a balanced anesthesia study?
A) 0.2 μg/kg/min B) 0.3 μg/kg/min C) 0.5 μg/kg/min D) 1.0 μg/kg/min
B) 0.3 μg/kg/min
What is the composition of the currently licensed form of ketamine?
A) Pure S-ketamine B) Pure R-ketamine C) Racemic mixture of S-ketamine and R-ketamine D) Mixture of ketamine and xylazine
C) Racemic mixture of S-ketamine and R-ketamine
What percentage reduction in halothane MAC was achieved with ketamine?
A) 25% B) 30% C) 37% D) 50%
C) 37%
What is the initial loading dose range for ketamine administered intravenously?
A) 0.1–0.3 mg/kg B) 0.1–0.2 mg/kg C) 0.3–0.4 mg/kg D) 0.5–1.0 mg/kg
B) 0.1–0.2 mg/kg
What is the infusion rate range for ketamine as a continuous rate infusion (CRI)?
A) 0.5–3 mg/kg/h B) 1–5 mg/kg/h C) 2–4 mg/kg/h D) 5–10 mg/kg/h
A) 0.5–3 mg/kg/h
How long does ketamine typically need to be infused to avoid emergence reactions?
A) Less than 1 hour B) 1–2 hours C) More than 2 hours D) Continuous infusion
B) 1–2 hours
What are some signs of emergence reactions from ketamine in horses?
A) Bradycardia and hypotension B) Mydriasis and ataxia C) Respiratory depression D) Drowsiness and sedation
B) Mydriasis and ataxia
At what concentration of S-ketamine was the target-controlled infusion aimed during isoflurane anesthesia?
A) 0.5 μg/mL B) 1 μg/mL C) 2 μg/mL D) 5 μg/mL
B) 1 μg/mL
What is the maximum recommended dose of additional boluses of racemic ketamine per hour?
A) 1 mg/kg/h B) 2 mg/kg/h C) 3 mg/kg/h D) 5 mg/kg/h
B) 2 mg/kg/h
What is the typical CRI dosage of S-ketamine to maintain anesthesia?
A) 0.1 mg/kg/h B) 0.5 mg/kg/h C) 1.0 mg/kg/h D) 2.0 mg/kg/h
B) 0.5 mg/kg/h
What adverse effect can occur from the use of high-dose opioids in horses during anesthesia?
A) Bradycardia B) Enhanced analgesia C) Violent recovery D) Sedation
C) Violent recovery
What is the recommended pre-emergence sedation for horses after anesthesia?
A) Opioids B) α2-adrenoceptor agonists C) Benzodiazepines D) Ketamine
B) α2-adrenoceptor agonists
What is the typical clinical dose range for guaifenesin?
A) 10–20 mg/kg B) 50–100 mg/kg C) 100–150 mg/kg D) 200–300 mg/kg
B) 50–100 mg/kg
What is the MAC value ?
minimum alveolar concentration (MAC), defined as the end-tidal alveolar concentration of inhalation anesthetic that prevents movement in 50% of subjects in response to a fixed noxious stimulus
What is the role of benzodiazepines in equine anesthesia?
A) Inducing analgesia B) Enhancing muscle relaxation C) Acting as sole anesthetic D) Increasing heart rate
B) Enhancing muscle relaxation
What is the maximum recommended duration for a ketamine CRI?
A) 30 minutes B) 60 minutes C) 90 minutes D) 120 minutes
D) 120 minutes
What is a significant risk associated with administering high-concentration guaifenesin?
A) Hemolysis B) Muscle rigidity C) Mydriasis D) Sedation
A) Hemolysis
Which benzodiazepine is commonly used in equine anesthesia?
A) Diazepam B) Midazolam C) Lorazepam D) Alprazolam
B) Midazolam
What is the suggested administration time for ketamine before the end of anesthesia?
A) 5–10 minutes B) 10–15 minutes C) 15–20 minutes D) 30–60 minutes
C) 15–20 minutes
What was the outcome of using low doses of ketamine perioperatively?
A) Increased postoperative pain B) Improved hemodynamic function C) No effect on recovery D) Increased emergence reactions
B) Improved hemodynamic function
What kind of anesthetic effects does ketamine provide?
A) Analgesia and sedation B) Amnesia and immobility C) Respiratory depression D) Cardiovascular collapse
B) Amnesia and immobility
What potential adverse effect can ketamine cause when used in prolonged infusions?
A) Hypotension B) Emergence reactions C) Bradycardia D) Nausea
B) Emergence reactions
What are the sympathomimetic effects of ketamine primarily responsible for?
A) Increased sedation B) Cardiovascular stimulation C) Respiratory depression D) Myorelaxation
B) Cardiovascular stimulation
What infusion rate of dexmedetomidine has been shown to lower MAC values in sevoflurane anesthesia?
A) 0.5 μg/kg/h B) 1.75 μg/kg/h C) 3.5 μg/kg/h D) 5 μg/kg/h
B) 1.75 μg/kg/h
What happens to the depth of anesthesia when using dissociative anesthetics like ketamine?
A) Increases reflex activity B) Decreases reflex activity C) Has no effect on reflexes D) Induces coma
B) Decreases reflex activity
What is the maximum recommended concentration of guaifenesin to avoid complications?
A) 5% B) 7% C) 10% D) 15%
C) 10%
What should be avoided when performing surgery on the upper airway and eyes while under ketamine?
A) High doses of opioids B) Use of α2-adrenoceptor agonists C) Use of ketamine as the predominant anesthetic D) Short-acting anesthetics
C) Use of ketamine as the predominant anesthetic
What is the typical loading dose of S-ketamine administered for balanced anesthesia?
A) 0.5 mg/kg B) 1.1 mg/kg C) 1.5 mg/kg D) 2.0 mg/kg
B) 1.1 mg/kg
What is a potential outcome of combining opioids with α2-adrenoceptor agonists?
A) Increased MAC B) Smoother recovery C) Poorer cardiovascular function D) Increased respiratory depression
B) Smoother recovery
How many horses were involved in the clinical study comparing S-ketamine and medetomidine?
A) 25 B) 50 C) 75 D) 100
B) 50
What is the effect of xylazine on halothane MAC values?
A) Increases MAC B) Decreases MAC C) No effect on MAC D) Variable effects
B) Decreases MAC
What percentage of horses showed thrombus formation after guaifenesin administration?
A) 10% B) 20% C) 40% D) 60%
C) 40%
What happens when morphine is administered in combination with xylazine?
A) Decreased analgesia B) Enhanced sedation C) No change in MAC D) Increased gastrointestinal motility
C) No change in MAC
Which molecule is primarily responsible for the excitatory CNS effects of ketamine?
A) S-norketamine B) R-ketamine C) Halothane D) Isoflurane
A) S-norketamine
What is the benefit of using S-ketamine over racemic ketamine?
A) Higher risk of emergence reactions B) Better recovery quality C) Increased cardiovascular depression D) Longer duration of action
B) Better recovery quality
What condition does “wind-up” refer to in the context of anesthesia?
A) Excessive sedation B) Chronic pain syndrome C) Hyperreactivity of the CNS D) Acute respiratory failure
C) Hyperreactivity of the CNS
What is a contraindication for using ketamine as a sole anesthetic?
A) Healthy horses B) Upper airway surgery C) Short procedures D) Young horses
B) Upper airway surgery
What is the duration for which muscle relaxants like guaifenesin do not significantly affect diaphragmatic function?
A) Short-term B) Prolonged C) Indefinite D) Immediate
A) Short-term
What effect does morphine have on gastrointestinal motility when used during anesthesia?
A) Increases motility B) No effect C) Decreases motility D) Induces vomiting
C) Decreases motility
What was the result of using a combination of guaifenesin, ketamine, and isoflurane?
A) Deteriorated cardiovascular performance B) Better or equivalent cardiovascular performance C) No effect on surgical anesthesia D) Increased MAC values
B) Better or equivalent cardiovascular performance
How does ketamine impact respiratory function in horses?
A) Significantly depresses it B) Causes respiratory failure C) Only minimally impairs it D) Has no effec
C) Only minimally impairs it
What is the infusion rate of morphine in mg/kg/h during anesthesia?
A) 0.05 mg/kg/h B) 0.10 mg/kg/h C) 0.15 mg/kg/h D) 0.20 mg/kg/h
B) 0.10 mg/kg/h
What percentage of horses needed active cooling during the high-dose fentanyl study?
A) 25% B) 33% C) 50% D) 67%
B) 33%
What was the bolus dose of butorphanol used in the study?
A) 0.01 mg/kg B) 0.02 mg/kg C) 0.025 mg/kg D) 0.03 mg/kg
B) 0.02 mg/kg
What was the CRI dosage for butorphanol in the study?
A) 25 μg/kg/h B) 50 μg/kg/h C) 100 μg/kg/h D) 200 μg/kg/h
A) 25 μg/kg/h
How much did xylazine reduce inhalant anesthetic MAC values?
A) 10% B) 20% C) 30% D) 40%
B) 20%
Which opioid was noted to improve recovery quality in horses?
A) Fentanyl B) Butorphanol C) Morphine D) Buprenorphine
C) Morphine
What percentage of horses experienced violent recoveries after high-dose Mu-opioid agonists?
A) 20% B) 50% C) 67% D) 100%
B) 50%
What was the significant finding when comparing morphine with xylazine?
A) Morphine reduced MAC further B) Xylazine did not affect MAC C) Morphine did not enhance xylazine's effect D) Both enhanced analgesia significantl
C) Morphine did not enhance xylazine’s effect
What concentration of guaifenesin led to thrombus formation in horses?
A) 5% B) 7% C) 10% D) 15%
C) 10%
What is the recommended approach to minimize ataxia caused by benzodiazepines post-anesthesia?
A) Increase dosage B) Use antagonists C) Delay recovery D) Provide additional sedation
B) Use antagonists
What was the dosage of buprenorphine given to ponies during castration?
A) 0.005 mg/kg B) 0.01 mg/kg C) 0.02 mg/kg D) 0.03 mg/kg
B) 0.01 mg/kg
What type of anesthetic techniques are used in human patients that may be applicable to horses?
A) General anesthesia B) Epidural techniques C) Inhalation anesthetics D) Topical anesthetics
B) Epidural techniques
Which local anesthetic is frequently used for perineural anesthesia in horses?
A) Bupivacaine B) Lidocaine C) Ropivacaine D) Mepivacaine
B) Lidocaine
What is the main action of guaifenesin in balanced anesthesia?
A) Analgesia B) Muscle relaxation C) Sedation D) Stimulation
B) Muscle relaxation
What is the potential complication of local anesthetic techniques mentioned in the text?
A) Vomiting B) Hematoma formation C) Hypotension D) Bradycardia
B) Hematoma formatio
What effect does butorphanol have when administered with isoflurane?
A) Increases heart rate B) Deepens anesthesia C) Causes violent recovery D) Increases MAC
B) Deepens anesthesia
what type of molecule is butorphanol?
mixed agonist-antagonist, meaning it activates some opioid receptors (like kappa receptors) while blocking others (like mu receptors). This dual action helps provide pain relief with a lower risk of respiratory depression compared to full agonists like morphine.
