PHARMACOLOGY | Inhaled Anesthetics Part I Flashcards
Clinically, what is the most potent volatile anesthetic?
A. Isoflurane
B. Sevoflurane
C. Desflurane
D. Halothane
Isoflurane
What is the clinical relevance of SOLUBILITY to UPTAKE?
The DICTUM is MORE SOLUBLE = GREATER UPTAKE = LONGER TIME REQUIRED FOR Fa to APPROACH Fi Which means LONGER INDUCTION TIME.
- Blood–gas solubility coefficient FOR inhalational anesthetics
- Which of the clinically available volatile anesthetics has the highest blood-gas solubility?
- (highest to lowest) HE IS Des
Halothane: 2.54
Enflurane: 1.9
Isoflurane: 1.46
Sevoflurane: 0.69
Desflurane: 0.42 - Halothane has the highest B:G solubility
Label the graph with the following inhaled anesthetics relative to its fA/fI
Nitrous Oxide
Isoflurane
Desflurane
Sevoflurane
FASTEST to SLOWEST
Nitrous Oxide > Desflurane > Sevoflurane > Isoflurane
Administration of nitrous oxide is associated with an increased concentration of what metabolite?
A. Homocysteine
B. Thiocyanate
C. Thymol
Homocysteine
The concentration of inhaled anesthetics that provide loss of awareness and recall:
A. 0.4 - 0.5 MAC
B. 1.0 MAC
C. 1.2 - 1.5 MAC
0.4 TO 0.5 MAC
Which volatile anesthetic is the least soluble in the blood?
A. Isoflurane
B. Desflurane
C. Halothane
D. Sevoflurane
DESFLURANE
Which volatile agent has the lowest blood:gas solubility?
A. Nitrous Oxide
B. Desflurane
C. Sevoflurane
D. Enflurane
DESFLURANE
The typical time to loss of consciousness when delivering 8% sevoflurane via the face mask is:
A. 1 minute
B. 30 seconds
C. 1 minute and 15 seconds
60 SECONDS | 1 Minute
Which volatile anesthetic is metabolized to trifluoroacetate, thereby causing hepatotoxicity through an immunologic mechanism involving trifluoroacetyl hapten formation and a resulting autoimmune response?
A. Halothane
B. Isoflurane
C. Sevoflurane
D. N2O
HALOTHANE
Which volatile anesthetic has the safest liver profile?
A. Sevoflurane
B. Isoflurane
C. Enflurane
SEVOFLURANE
Factors that can increase the RATE of fI/fA concentration:
Low Blood Solubility
Low CARDIAC OUTPUT
High Minute Ventilation
High pulmonary to arterial venous pressure
Which volatile agent is clinically ideal for Obese as it permits rapid emergence even with prolonged surgical procedures and in obese patients?
A. Desflurane
B. Isoflurane
C. Sevoflurane
Desflurane
Ether-based volatile anesthetics which MAINTAIN or INCREASE hepatic artery blood flow:
S I D
Sevoflurane
Isoflurane
Desflurane
Which tissue group plays the greatest role in determining emergence time?
A. Brain
B. Fat
C. Skeletal muscle
D. Liver
FAT
This refers to the highest temperature at which a GAS CAN EXIST in liquid form:
A. Critical temperature
B. Boiling point
C. Saturated vapor pressure
CRITICAL TEMPERATURE
Which volatile agent has a critical temperature 36.5°C and can remain a liquid at room temperature?
A. Desflurane
B. Sevoflurane
C. Xenon
D. Nitrous Oxide
A. Desflurane
True or False
Nitrous oxide does not affect skeletal muscle relaxation
TRUE
All volatile agent increases respiratory rate and decrease MV except one. Which volatile agent does not increase respiratory rate above 1 MAC.
A.Isoflurane
B. SEVOFLURANE
C. XENON
D. NITROUS OXIDE
A. Isoflurane
Which of the following is least likely an early sign of Malignant Hyperthermia?
A. Hyperthermia
B. Tachycardia
C. Elevated ETCO2
D. Masseter Spasm or rigidity
A. Hyperthermia
Sevoflurane and Desflurane are similar in terms of:
FLUORINE as the Halogen substitution which is the reason for their MINIMAL METABOLISM.
The Vapor Pressure of Desflurane?
A. 669
B. 38,000
C. 157
669
True of False? As temperature increases, Vapor pressure increases?
TRUE
The anesthetic agent passes via SIMPLE DIFFUSION from blood to tissues as well as between tissues.
TRUE
Anesthetic potency or effect is dependent on the partial pressure of the gas, not the concentration of the agent?
TRUE
This volatile anesthetic INHIBITS HPV (Hypoxic Pulmonary Vasoconstriction)
A. Sevoflurane
B. Isoflurane
C. Halothane
SEVOFLURANE
ACUTE AMPHETAMINE USE effect on MAC value?
A. Increase
B. Decrease
C. No change
INCREASE in MAC
THREE FACTORS that affects the UPTAKE of volatile anesthetics
- Solubility in the blood
- Alveolar blood flow
- Difference in partial pressure between alveolar gas and venous blood
The anesthetic agents are taken up by the Pulmonary circulation during INDUCTION, hence the alveolar concentrations LAG behind inspired concentrations (FA/fI <1.0)
TRUE
What is the effect of a R to L shunt on speed on inhaled induction?
A. Slow induction
B. Fast induction
C. NO change
Slows induction
Why can’t N2O be used as a sole anesthetic?
Nitrous oxide’s low oil-gas coefficient indicates its low potency. It is the low oil-gas coefficient, the low potency, and the high MAC of nitrous that preclude its use as a sole anesthetic agent.
What is the Nephrotoxic concentrations of compound A?
A. > 100ppm
B. <100 ppm
more than 100 ppm
Decrease in the functional residual capacity will cause a ___ onset of anesthetics:
A. Faster
B. Slower
C. No change
A. Faster
Decreases in the functional residual capacity will cause a faster onset of anesthetics.
- if the FRC is decreased, the anatomic dead space will also decrease thus increase fA/fI > FASTER ONSET
Fluorination of inhaled anesthetics effect on lipid solubility is:
A. Decrease
B. Increase
Fluorination of inhaled anesthetics DECREASES the lipid solubility
Low/Decrease Lipid Solubility = Low metabolism of the agent!
Note: This is also the reason why it doesn’t blow up in the OR.:)
This states that all anesthetics share a similar mechanism of action but work at different sites.
A. Meyer-Overton
B. Unitary Hypothesis
B. Unitary Hypothesis
Which of the following condition increases the risk of Nitrous oxide complications?
A. Vitamin B12 deficiency
B. Vitamin B6 deficiency
C. Vitamin A
D. Aplastic Anemia
A. Vitamin B12 deficiency
Pernicious anemia or Alcoholism causes Vitamin B12 deficiency > Increase risk of Nitrous oxide complications
What type of evoked potentials are most resistant to anesthetic effects?
A. (BAEP) Brain auditory evoked potential
B. SSEP Somatosensory evoked potential
C. (VEP) Visual evoked potential
A. (BAEP) Brain auditory evoked potential
What type of evoked potentials are most SENSITIVE to anesthetic effects?
A. (BAEP) Brain auditory evoked potential
B. SSEP Somatosensory evoked potential
C. (VEP) Visual evoked potential
C. (VEP) Visual evoked potential
Which inhaled anesthetic is best choice for COPD patients?
A. Desflurane
B. Sevoflurane
C. Isoflurane
D. Enflurane
A. Desflurane
It causes the LEAST blunting of hypoxic drive.
Which inhaled anesthetic is best choice for sleep apnea patients?
A. Sevoflurane
B. Isoflurane
C. Enflurane
D. Desflurane
D. Desflurane
Less impaired hypoxic drive > better induction
The concentration of a specific gas in solution depends on which of the following?
A. Temperature of the solution
B. Volume of the system
C. Solubility of the specific gas in that solution
D. Molecular weight of the gas
C. Solubility of the specific gas in that solution
Which of the following statements is true about the partial pressure of a gas at equilibrium?
A. Directly proportional to its concentration of gas in solution
B. Inversely proportional to its concentration of gas in solution
C. Less than its concentration of gas in solution
D. Greater than its concentration of gas in solution
A. Directly proportional to its concentration of gas in solution
A vaporizer is mishandled and accidentally tipped on its side. Which of the following is the best course of action to take?
A. Run high fresh gas flows with the dial set to a high concentration for 30 minutes
B. Run high fresh gas flows with the dial set to a low concentration for 30 minutes
C. Run low fresh gas flows with the dial set to a low concentration for 30 minutes
D. Run low fresh gas flows with the dial set to a high concentration for 30 minutes
A. Run high fresh gas flows with the dial set to a high concentration for 30 minutes
This will cause INCREASED VAPOR PRESSURE CONCENTRATIONS when delivering the anesthetic.
Which of the following would increase the output concentration of a volatile anesthetic from a vaporizer?
A. Fresh gas flow rate of 100 mL/min
B. Fresh gas flow rate of 20 L/min
C. Decreased operating room temperature
D. Significantly increasing the ratio of oxygen to nitrous oxide
D. Significantly increasing the ratio of oxygen to nitrous oxide
Which of the following statements defines the critical temperature?
A. The temperature at which a liquid will boil
B. The highest temperature at which a gas can exist in liquid form
C. The temperature at which a substance can exist as a gas or liquid
D. The temperature at which a solid becomes a liquid
B. The highest temperature at which a gas can exist in liquid form
Which of the following agents can cause an increase in CBF and CMRO2?
A. Nitrous oxide
B. Desflurane
C. Halothane
D. Sevoflurane
A. Nitrous oxide
When given alone, N2O causes mild cerebral vasodilation and INCREASE in CBF and CMRO2.
PHYSICAL PROPERTIES of VOLATILE ANESTHETHICS
Sevoflurane results in a decrease of all of the following
parameters EXCEPT
A. Glomerular filtration rate
B. Systemic vascular resistance
C. Cerebral metabolic oxygen rate
D. Portal vein blood flow
E. Cerebral blood flow
E. Cerebral blood flow
Which of the following regarding potent inhalational
anesthetics is TRUE in children compared to adults?
A. Volatile anesthetics depress ventilation more in
adults than infants
B. Children are at an increased risk of halothane
hepatitis compared to adults
C. Increased tidal volume in children increases
induction rates compared to adults
D. The MAC of inhalational agents is higher in infants
compared to adults
E. Inhalational anesthetics have a higher blood-gas
coeffi cient in children compared to adults
D. The MAC of inhalational agents is higher in infants
compared to adults
A 19-year-old girl with Eisenmenger syndrome presents
to the operating room for a laparoscopic appendectomy.
Inhalational induction with which agent will be
most affected (slowest) by this patient’s cardiopulmonary
physiology?
A. Desflurane
B. Isoflurane
C. Sevoflurane
D. Halothane
E. Enflurane
A. Desflurane
Eisenmenger’s complex : right-to-left intracardiac
shunting after chronic left -to-right shunting results in
chronic pulmonary hypertension and elevated right
heart pressures
- Right-to-left intracardiac shunts and transpulmonary
shunts (like endobronchial intubations) result in
SLOWING of induction - Insoluble agents are more affected by this type of lesion
than soluble agents
Emergence delirium (ED) occurs most often with:
A. Sevoflurane
B. Desflurane
C. Ketamine
D. Propofol
A. Sevoflurane
