NUR 751 Volatile Anesthetics–Questions and
Answers | 2026 Update | 100% Correct.
desired characteristics for volatiles/ inhaled agents
nonflammable, poor lipid solubility, resistant to metabolism, favorable recovery profile, minimal
side effects, simple delivery, versatility, favorable hemodynamic characteristics
what decreases combustibility in volatiles?
fluoride and chloride halogens.
halogenation with fluoride increases stability and lowers toxicity compared to chloride
cost consideration for volatiles?
price per mL
vapor pressure (if doesnt vaporize quickly)
potency (less potent=we use more)
solubility
flow
how fast can we wake up the patient
what is MAC and what does it measure?
minimum alveolar concetration, potency
what is the definition of MAC
the concentration at 1 atmosphere (760 mmHg) that prevents skeletal muscle movement in
response to a supra maximal painful stimulus like a surgical incision in 50% of patients
,1 MAC can be considered as?
ED50 of inhaled anesthetics
MAC values are?
additive
standard deviation is approximately?
10% and is distributed on a bell curve
68% of pts will not move at 1.1 MAC
95% of pts will not move at 1.2 MAC
99% of pts will not move at 1.3 MAC
how do you calculate MAC?
amount (%) of volatile/ its designated MAC value
example: 1% of Sevo/ 2% = 0.5 MAC
What is MAC-BAR?
MAC bar (Minimum Alveolar Concentration - blocking autonomic responses) refers to the
concentration of an inhaled anesthetic that prevents autonomic nervous system responses, such
as increased heart rate and blood pressure, to a surgical incision.
what is MAC amnesia?
MAC required to produce amnesia, variable
what are some factors that increase MAC required?
, drugs, age, electrolytes, hair color, hyperthermia (red hair need more narcotics usually too
especially desflurane)
which drugs increase MAC required
acute amphetamine, cocaine, chronic alcohol use due to increased tolerance
what are some factors decreasing MAC requirement?
drugs, age, electrolytes, physiologic disturbances like anemia, hypoxia, hypercarbia (PaCO2 of
70=0.5 MAC), pregnancy
which drugs decrease MAC required
propofol, etomidate, opios, acute ETOH, BZDs, ketamine
how does hypernatremia or hyponatremia affect MAC?
hypernatremia causes easier depolarization, when volatiles work on GABA, chloride channels
open and if if you have more sodium go into the cells, chloride channels aren't going to inhibit
depolarization as much.
hyponatremia: if you give something that will block chloride channels and pt has hyponatremia,
it will further suppress depolarization.
What is the MAC of nitrous oxide?
104
What is the BGC of nitrous oxide?
0.47
Answers | 2026 Update | 100% Correct.
desired characteristics for volatiles/ inhaled agents
nonflammable, poor lipid solubility, resistant to metabolism, favorable recovery profile, minimal
side effects, simple delivery, versatility, favorable hemodynamic characteristics
what decreases combustibility in volatiles?
fluoride and chloride halogens.
halogenation with fluoride increases stability and lowers toxicity compared to chloride
cost consideration for volatiles?
price per mL
vapor pressure (if doesnt vaporize quickly)
potency (less potent=we use more)
solubility
flow
how fast can we wake up the patient
what is MAC and what does it measure?
minimum alveolar concetration, potency
what is the definition of MAC
the concentration at 1 atmosphere (760 mmHg) that prevents skeletal muscle movement in
response to a supra maximal painful stimulus like a surgical incision in 50% of patients
,1 MAC can be considered as?
ED50 of inhaled anesthetics
MAC values are?
additive
standard deviation is approximately?
10% and is distributed on a bell curve
68% of pts will not move at 1.1 MAC
95% of pts will not move at 1.2 MAC
99% of pts will not move at 1.3 MAC
how do you calculate MAC?
amount (%) of volatile/ its designated MAC value
example: 1% of Sevo/ 2% = 0.5 MAC
What is MAC-BAR?
MAC bar (Minimum Alveolar Concentration - blocking autonomic responses) refers to the
concentration of an inhaled anesthetic that prevents autonomic nervous system responses, such
as increased heart rate and blood pressure, to a surgical incision.
what is MAC amnesia?
MAC required to produce amnesia, variable
what are some factors that increase MAC required?
, drugs, age, electrolytes, hair color, hyperthermia (red hair need more narcotics usually too
especially desflurane)
which drugs increase MAC required
acute amphetamine, cocaine, chronic alcohol use due to increased tolerance
what are some factors decreasing MAC requirement?
drugs, age, electrolytes, physiologic disturbances like anemia, hypoxia, hypercarbia (PaCO2 of
70=0.5 MAC), pregnancy
which drugs decrease MAC required
propofol, etomidate, opios, acute ETOH, BZDs, ketamine
how does hypernatremia or hyponatremia affect MAC?
hypernatremia causes easier depolarization, when volatiles work on GABA, chloride channels
open and if if you have more sodium go into the cells, chloride channels aren't going to inhibit
depolarization as much.
hyponatremia: if you give something that will block chloride channels and pt has hyponatremia,
it will further suppress depolarization.
What is the MAC of nitrous oxide?
104
What is the BGC of nitrous oxide?
0.47
