Exam2 IAs Flashcards
Isoflurane 1 MAC
1.17%
Sevoflurane 1 MAC
1.80%
Desflurane 1 MAC
6.6%
Nitrous Oxide 1 MAC
104%
MAC
alveolar concentration at which 50% of subjects move in response to a noxious stimuli
Factors that increase MAC
CNS stimulants alcohol abuser young age (highest 6months) hypernatremia hyperthermia hyperthyroidism red haired females
Factors that decrease MAC
other drugs, elderly, electrolyte disturbance (hyponatremia), hypercarbic, hypothermic, hypoxic, pregnant, anemia
MAC fractions/multiples of inhalation agents are ______
additive
of MAC that prevents movement in 95% of patients on incision
1.3 MAC
Non-volatile anesthetics`
N2O
Volatile anesthetics
isoflurane, sevoflurane, desflurane
MACawake numeric value
1/3 MAC for most IAs
MACaware
concentration at which pt can remember events
MAC-BAR
average alveolar concentration which Blunts the Autonomic Response to a noxious stimuli (incision)
MAC-BAR is _____ compared to MAC
in excess
MAC-BAR50 for Sevo (combined with 66% N2O)
2.2
MAC-BAR50 for Sevo
2.2
MACaware is related to _____ not ________
amnesia not consciousness
MACaware numeric value
varies per patient
Pa measures?
partial pressure of agent in alveoli
______ is an indirect, yet reliable measure of Pbr
Pa
Fa
fractional concentration of anesthetic in the alveoli
Fi
fractional concentration of anesthetic in the inspired gas
OR
inspired concentration
cardiac output moves agent throughout body
distribution
evaluating uptake of inhaled anesthetics
Evaluating relationship between Fa and Fi
The faster Fa/Fi approaches _____ (#), the faster ______ will occur
1; induction
The less soluble the agent, the ____ the rate of rise (induction)
faster
Isoflurane Blood:Gas Partition Coeff.
1.46
Sevoflurane Blood:Gas Partition Coeff.
0.69
N2O Blood:Gas Partition Coeff.
0.46
Desflurane Blood:Gas Partition Coeff.
0.42
Factors that affect FA/FI
Solubility
Minute Ventilation and FRC
Cardiac Output
Anesthesia circuit characteristics
______ FRC will speed induction
decreased
________ is the most important factor in the rate of rise of the FA/FI
uptake
Uptake_______ the rate of rise of the Fa/Fi
slows
As cardiac output ______, Fa is lowered even more
increases
An increase in cardiac output will ______ uptake and _____ induction
increase uptake, slow induction
A _______ in cardiac output will ______ an inhalation induction
decrease; speed
Higher flow rates will ______ induction
speed up
Absorption of the circuit: if the circuit itself can absorb the anesthetic, ____ reaches the patient
less
Three factors of anesthesia circuit that effect induction speed
- fresh gas flows > 4LPM
- absorption by the circuit
- total circuit volume
Factors that increas speed of induction
Increased MV, fresh gas flow rate
Decreased agent solubility, CO, FRC, circuit volume
How do we know Fa?
exhaled concentrations by gas analyzer (mass spectrometry)
What is our most distal measurement?
Pa