, Stoelting's Pharmacology & Physiology in Anesthetic
Practice, 6th Edition High Value 80 NCLEX-Style
Questions on Inhaled Anesthetics, IV Sedatives, Opioids,
NMBs & Local Anesthetics – Part II Neurologic System.
Part A: Inhaled Anesthetics
15 Questions with Answers and Detailed Rationales
1. A 45-year-old patient is scheduled for laparoscopic cholecystectomy.
The anesthesia provider plans to use sevoflurane for maintenance.
Which property of sevoflurane makes it particularly suitable for
inhalational induction in pediatric populations but also requires
consideration in this adult patient?
A) Pungent odor causing breath-holding
B) Low blood:gas partition coefficient
C) Production of compound A in low-flow systems
D) Coronary steal phenomenon
Answer: C
Rationale: Sevoflurane is nonpungent and pleasant to inhale, making it ideal
for inhalational induction. However, it reacts with carbon dioxide absorbents
(especially when dry or with baralyme) to produce compound A, a
,nephrotoxic vinyl ether. Low-flow anesthesia increases the risk of compound
A accumulation. Option A is incorrect—sevoflurane has minimal pungency.
Option B is correct about sevoflurane's properties but describes its rapid
onset/offset, not a safety consideration. Option D is associated with isoflurane.
2. A 65-year-old patient with coronary artery disease is undergoing
abdominal surgery. The anesthesia provider chooses isoflurane for
maintenance. Which statement accurately describes a concern specific to
isoflurane in this patient?
A) It sensitizes the myocardium to catecholamines more than halothane
B) It causes dose-dependent coronary vasodilation that may lead to coronary
steal syndrome
C) It significantly depresses myocardial contractility more than other agents
D) It increases heart rate less than desflurane
Answer: B
Rationale: Isoflurane causes dose-dependent coronary vasodilation, which
can theoretically divert blood flow away from collateral-dependent areas to
normally perfused areas (coronary steal syndrome). While controversial, this
is a consideration in patients with coronary artery disease. Option A is
incorrect—halothane sensitizes the myocardium more than isoflurane. Option
C is incorrect—isoflurane causes less myocardial depression than halothane
or enflurane. Option D is incorrect—isoflurane does increase heart rate,
though desflurane causes more pronounced sympathetic activation.
,3. A patient emerges from general anesthesia and develops hypoxemia
in the post-anesthesia care unit. The anesthesia provider suspects
diffusion hypoxia. Which agent was most likely used?
A) Sevoflurane
B) Isoflurane
C) Nitrous oxide
D) Propofol
Answer: C
Rationale: Diffusion hypoxia occurs when nitrous oxide is discontinued.
Nitrous oxide diffuses rapidly from blood into alveoli, diluting alveolar oxygen
concentration and potentially causing hypoxemia. Prevention includes
administering 100% oxygen at the end of nitrous oxide anesthesia.
Sevoflurane (A) and isoflurane (B) do not cause this phenomenon. Propofol
(D) is an IV agent, not an inhaled anesthetic.
4. A 30-year-old patient with no significant medical history undergoes
general anesthesia with desflurane for a 2-hour procedure. Upon
emergence, the patient develops tachycardia and hypertension. Which
property of desflurane best explains this finding?
,A) High blood:gas partition coefficient
B) Pungent odor causing airway irritation
C) Rapid increase in concentration causing sympathetic nervous system
stimulation
D) Decreased MAC in young adults
Answer: C
Rationale: Desflurane causes transient but marked sympathetic nervous
system stimulation when its concentration is rapidly increased, leading to
tachycardia and hypertension. This effect is unique among inhaled
anesthetics. Option A is incorrect—desflurane has a low blood:gas partition
coefficient. Option B describes its pungency but doesn't directly explain the
sympathetic response. Option D is incorrect—MAC decreases with age, so
young adults have higher MAC requirements.
5. Which statement correctly describes the effect of patient age on
minimum alveolar concentration (MAC) for inhaled anesthetics?
A) MAC increases with advancing age
B) MAC is highest in neonates and decreases with age
C) MAC is lowest in infants and increases throughout adulthood
D) MAC remains constant across all age groups
Answer: B
, Rationale: MAC is highest in neonates and infants, then gradually decreases
with age. A 1-year-old has the highest MAC requirement, while an 80-year-old
requires approximately 40-50% lower MAC. This reflects age-related changes
in central nervous system sensitivity and anesthetic requirements. Options A,
C, and D are incorrect.
6. A 70-year-old patient is scheduled for hip replacement surgery. The
anesthesia provider calculates the MAC fraction for desflurane. If the
patient's MAC for desflurane is 5.0% and the end-tidal concentration is
2.5%, what is the MAC fraction?
A) 0.25
B) 0.50
C) 1.0
D) 2.0
Answer: B
Rationale: MAC fraction = (End-tidal concentration) / (MAC value). 2.5% /
5.0% = 0.5 MAC. This concept is clinically important because MAC fractions
are additive. For example, 0.5 MAC desflurane plus 0.5 MAC nitrous oxide
provides 1.0 MAC total. Options A, C, and D are incorrect calculations.
Practice, 6th Edition High Value 80 NCLEX-Style
Questions on Inhaled Anesthetics, IV Sedatives, Opioids,
NMBs & Local Anesthetics – Part II Neurologic System.
Part A: Inhaled Anesthetics
15 Questions with Answers and Detailed Rationales
1. A 45-year-old patient is scheduled for laparoscopic cholecystectomy.
The anesthesia provider plans to use sevoflurane for maintenance.
Which property of sevoflurane makes it particularly suitable for
inhalational induction in pediatric populations but also requires
consideration in this adult patient?
A) Pungent odor causing breath-holding
B) Low blood:gas partition coefficient
C) Production of compound A in low-flow systems
D) Coronary steal phenomenon
Answer: C
Rationale: Sevoflurane is nonpungent and pleasant to inhale, making it ideal
for inhalational induction. However, it reacts with carbon dioxide absorbents
(especially when dry or with baralyme) to produce compound A, a
,nephrotoxic vinyl ether. Low-flow anesthesia increases the risk of compound
A accumulation. Option A is incorrect—sevoflurane has minimal pungency.
Option B is correct about sevoflurane's properties but describes its rapid
onset/offset, not a safety consideration. Option D is associated with isoflurane.
2. A 65-year-old patient with coronary artery disease is undergoing
abdominal surgery. The anesthesia provider chooses isoflurane for
maintenance. Which statement accurately describes a concern specific to
isoflurane in this patient?
A) It sensitizes the myocardium to catecholamines more than halothane
B) It causes dose-dependent coronary vasodilation that may lead to coronary
steal syndrome
C) It significantly depresses myocardial contractility more than other agents
D) It increases heart rate less than desflurane
Answer: B
Rationale: Isoflurane causes dose-dependent coronary vasodilation, which
can theoretically divert blood flow away from collateral-dependent areas to
normally perfused areas (coronary steal syndrome). While controversial, this
is a consideration in patients with coronary artery disease. Option A is
incorrect—halothane sensitizes the myocardium more than isoflurane. Option
C is incorrect—isoflurane causes less myocardial depression than halothane
or enflurane. Option D is incorrect—isoflurane does increase heart rate,
though desflurane causes more pronounced sympathetic activation.
,3. A patient emerges from general anesthesia and develops hypoxemia
in the post-anesthesia care unit. The anesthesia provider suspects
diffusion hypoxia. Which agent was most likely used?
A) Sevoflurane
B) Isoflurane
C) Nitrous oxide
D) Propofol
Answer: C
Rationale: Diffusion hypoxia occurs when nitrous oxide is discontinued.
Nitrous oxide diffuses rapidly from blood into alveoli, diluting alveolar oxygen
concentration and potentially causing hypoxemia. Prevention includes
administering 100% oxygen at the end of nitrous oxide anesthesia.
Sevoflurane (A) and isoflurane (B) do not cause this phenomenon. Propofol
(D) is an IV agent, not an inhaled anesthetic.
4. A 30-year-old patient with no significant medical history undergoes
general anesthesia with desflurane for a 2-hour procedure. Upon
emergence, the patient develops tachycardia and hypertension. Which
property of desflurane best explains this finding?
,A) High blood:gas partition coefficient
B) Pungent odor causing airway irritation
C) Rapid increase in concentration causing sympathetic nervous system
stimulation
D) Decreased MAC in young adults
Answer: C
Rationale: Desflurane causes transient but marked sympathetic nervous
system stimulation when its concentration is rapidly increased, leading to
tachycardia and hypertension. This effect is unique among inhaled
anesthetics. Option A is incorrect—desflurane has a low blood:gas partition
coefficient. Option B describes its pungency but doesn't directly explain the
sympathetic response. Option D is incorrect—MAC decreases with age, so
young adults have higher MAC requirements.
5. Which statement correctly describes the effect of patient age on
minimum alveolar concentration (MAC) for inhaled anesthetics?
A) MAC increases with advancing age
B) MAC is highest in neonates and decreases with age
C) MAC is lowest in infants and increases throughout adulthood
D) MAC remains constant across all age groups
Answer: B
, Rationale: MAC is highest in neonates and infants, then gradually decreases
with age. A 1-year-old has the highest MAC requirement, while an 80-year-old
requires approximately 40-50% lower MAC. This reflects age-related changes
in central nervous system sensitivity and anesthetic requirements. Options A,
C, and D are incorrect.
6. A 70-year-old patient is scheduled for hip replacement surgery. The
anesthesia provider calculates the MAC fraction for desflurane. If the
patient's MAC for desflurane is 5.0% and the end-tidal concentration is
2.5%, what is the MAC fraction?
A) 0.25
B) 0.50
C) 1.0
D) 2.0
Answer: B
Rationale: MAC fraction = (End-tidal concentration) / (MAC value). 2.5% /
5.0% = 0.5 MAC. This concept is clinically important because MAC fractions
are additive. For example, 0.5 MAC desflurane plus 0.5 MAC nitrous oxide
provides 1.0 MAC total. Options A, C, and D are incorrect calculations.
