Volatile Information to Know Flashcards
Know V/Q matching
What is the MAC (Minimum Alveolar Concentration) of CO2?
A) 50
B) 100
C) 200
D) 300
E) 400
C) 200
Which of the following strategies can help speed up the equilibrium of the blood
partition coefficient (Fa/Fi ratio) for inhalation anesthetics? (Select 3)
A) Increase the concentration of the inhalation anesthetic
B) Use an anesthetic with a lower blood
partition coefficient
C) Decrease the inspired concentration of the anesthetic
D) Increase the rate of ventilation
E) Use a gas with high solubility in blood
A) Increase the concentration of the inhalation anesthetic
B) Use an anesthetic with a lower blood
partition coefficient
D) Increase the rate of ventilation
-How do you speed up equilibrium of blood:gas (Fa/Fi ratio)?
-Concentration Effect: The higher concentration of inhalation anesthetic (N2O) delivered to the alveolus, the faster the onset of action.
What effect does the use of Nitrous Oxide (N2O) have on the onset of a second gas (volatile anesthetic) during anesthetic induction? (Select 2)
A) N2O rapidly increases the alveolar concentration of the second gas due to its high solubility in blood.
B) The uptake of N2O into the alveolus causes the alveolar volume to shrink, increasing the concentration of the second gas.
C) N2O decreases the rate at which the second gas reaches the alveoli.
D) The use of N2O during induction decreases the alveolar ventilation and delays the onset of the second gas.
E) The Second Gas Effect increases the FA/Fi ratio of the second gas.
B) The uptake of N2O into the alveolus causes the alveolar volume to shrink, increasing the concentration of the second gas.
E) The Second Gas Effect increases the FA/Fi ratio of the second gas.
*
-Second Gas Effect: The use of N2O during anesthetic induction will hasten the onset of a second gas (volatile). Rapid uptake of N2O into alveolus will cause it to shrink. The reduction in alveolar volume and augmented tracheal inflow on subsequent breath causes a relative increase in concentration of the second gas. This increases alveolar ventilation and augments FA.*
How is the MAC of different gases and anesthetics compounded when considering their combined effects?
A) The MAC values are multiplied together.
B) The MAC values are added together.
C) The MAC values are averaged.
D) The MAC values are used to calculate a weighted average based on their concentrations.
E) The MAC values are used individually without compounding.
B) The MAC values are added together.
Which of the following methods can be used to speed up the equilibrium of the blood
partition (Fa/Fi ratio) for inhalation anesthetics? (Select 4)
A) Decreased Cardiac Output (CO)
B) Increased Alveolar Ventilation (Vm)
C) Increased Fresh Gas Flow (FGF)
D) Decreased Functional Residual Capacity (FRC)
E) Decreased Alveolar Ventilation (Vm)
A) Decreased Cardiac Output (CO)
B) Increased Alveolar Ventilation (Vm)
C) Increased Fresh Gas Flow (FGF)
D) Decreased Functional Residual Capacity (FRC)
How does MAC (Minimum Alveolar Concentration) of volatile anesthetics affect cerebral autoregulation?
A) Volatile anesthetics disrupt autoregulation in a dose-dependent manner, increasing the dependence of cerebral blood flow on blood pressure
B) Higher MAC values enhance cerebral autoregulation, maintaining constant cerebral blood flow regardless of blood pressure changes
C) Lower MAC values have no effect on cerebral autoregulation, as they do not impact blood pressure dependency
D) As MAC increases, cerebral blood flow becomes less dependent on blood pressure due to improved autoregulation
E) Volatile anesthetics affect autoregulation but not in a dose-dependent manner
A) Volatile anesthetics disrupt autoregulation in a dose-dependent manner, increasing the dependence of cerebral blood flow on blood pressure
-How does MAC affect autoregulation?
The cerebral vasculature continuously adjusts vessel diameter to maintain a constant cerebral blood flow between cerebral perfusion pressure of 50-150 mmHg.
Volatile anesthetics disrupt autoregulation in a dose-dependent fashion. Cerebral blood flow becomes increasingly dependent on blood pressure as the concentration of the volatile agent is increased.
How do volatile anesthetics affect EEG mapping and motor mapping during surgery? (Select 2)
A) Volatile anesthetics can decrease the amplitude and increase the latency of EEG signals, indicating potential nerve ischemia
B) They have no impact on EEG mapping or motor mapping, as they do not affect nerve conduction or brain activity
C) Volatile anesthetics can cause a significant decrease in amplitude (>50%) or increase in latency (>10%) in EEG or motor mapping, which should raise concern for nerve ischemia
D) The primary effect of volatile anesthetics is to increase the amplitude of motor responses, improving motor mapping accuracy
E) They only affect EEG mapping, not motor mapping, by causing a decrease in signal amplitude and increased latency
A) Volatile anesthetics can decrease the amplitude and increase the latency of EEG signals, indicating potential nerve ischemia
C) Volatile anesthetics can cause a significant decrease in amplitude (>50%) or increase in latency (>10%) in EEG or motor mapping, which should raise concern for nerve ischemia
-How do they affect EEG mapping; and motor mapping?
-As a general rule, you should be concerned about nerve ischemia when amplitude decreases by > or = 50% or latency increases by > or = 10%
Here’s a test question with multiple-choice and multiple-answer options based on the effects of volatile anesthetics and nitrous oxide (N₂O) on EEG and motor mapping:
Question
How do volatile anesthetics and the addition of nitrous oxide (N₂O) affect EEG mapping and motor mapping during surgery?
A) Volatile anesthetics decrease amplitude and increase latency, and the addition of N₂O exacerbates these effects
B) Volatile anesthetics increase amplitude and decrease latency, while N₂O has no additional effect
C) The addition of N₂O improves amplitude and latency of EEG and motor mapping when used with volatile anesthetics
D) N₂O does not affect EEG or motor mapping when combined with volatile anesthetics
E) Volatile anesthetics have no effect on amplitude or latency, but N₂O decreases amplitude and increases latency
A) Volatile anesthetics decrease amplitude and increase latency, and the addition of N₂O exacerbates these effects
Which of the following factors can affect the amplitude and/or latency of EEG and motor mapping during surgery? (Select 3)
A) Hypoxia
B) Hypercarbia
C) Hypothermia
D) Hyperthermia
E) Hyperglycemia
A) Hypoxia
B) Hypercarbia
C) Hypothermia
To minimize the effects of nerve ischemia on sensory-evoked potentials (SEPs) and other neural mappings during surgery, what is the recommended approach?
A) Increase the dosage of volatile anesthetics to enhance anesthesia depth
B) Continue using volatile anesthetics but adjust the concentration based on monitoring
C) Omit or reduce the use of volatile agents in favor of an intravenous technique
D) Increase the use of muscle relaxants to prevent nerve ischemia
E) Administer supplemental oxygen to mitigate nerve ischemia effects
C) Omit or reduce the use of volatile agents in favor of an intravenous technique
-Nerve ischemia also decreases amplitude and increases latency. So we don’t confuse the issue, we either omit or reduce our use of volatile agents in favor of an intravenous technique
What is the best anesthetic approach to avoid interference with sensory-evoked potentials (SSEPs) and other neural mappings during surgery? (Select 2)
A) Use TIVA (Total Intravenous Anesthesia) without N2O
B) Use 1.0 MAC of volatile anesthetics along with N2O
C) Use 0.5 MAC of volatile anesthetics with N2O
D) Use 0.5 MAC of volatile anesthetics combined with opiates but avoid N2O
E) Use 1.0 MAC of volatile anesthetics with opiates
A) Use TIVA (Total Intravenous Anesthesia) without N2O
D) Use 0.5 MAC of volatile anesthetics combined with opiates but avoid N2O
-Nerve ischemia also decreases amplitude and increases latency. So we don’t confuse the issue, we either omit or reduce our use of volatile agents in favor of an intravenous technique. Use TIVA w/o N2O if you don’t want to affect SSEPs and other mappings, if not… use 0.5% MAC and opiates or other methods but still no N2O.
