Solubility Flashcards
- particular temperature
- amount of given gas dissolved
- partial pressure in equilibrium
Henry’s Law
If we double the pressure on a liquid in a container, we would expect more/less molecules in the liquid.
more
If we increase the temperature of the liquid in the container, we expect the amount of gas in the liquid to be more/less.
less
Gas is more soluble in _____ than in _____.
blood
water
The partial pressure of N2O in water and blood at 37ºC is:
1 atm in both instances
The _____ solubility coefficient is the volume of gas corrected to STP which dissolves into one unit volume of the liquid at the ________ concerned, where the partial pressure of the gas above the liquid is one standard atmosphere pressure.
Bunsen
temperature
- V1 = V2
- T1 T2
The volume of gas which dissolves in one unit volume of the liquid at the temperature concerned.
The volume of the gas is not measured in STP, but rather is measured at a known temperature and pressure.
Ostwald solubility coefficient
The Ostwald coefficient is independent of pressure. True or false?
True
The ratio of the amount of substance present in one phase compared with another, the two phases being of equal volume and in equilibrium.
partition coefficient
Blood gas coefficient of N20
0.47
Oil/blood partition coefficient of N2O at 37C
Blood oil partition is:
- 98 (1.4Liters/0.47Liters)
- 34
Arterial oxygen content equation:
(Hgb x 1.36 x SaO2) + (0.0031 x PaO2)
SaO2 = % of hemoglobin saturated with oxygen
(Normal range: 93-100%)
Hgb = hemoglobin Normal range(Adults): Male: 13-18 g/dl Female: 12-16 g/dl
PaO2= Arterial oxygen partial pressure
(Normal range: 80-100)
CaO2: Directly reflects the total number of oxygen molecules in arterial blood (both bound and unbound to hemoglobin)
Solubility of oxygen in plasma at 1 atmosphere is:
0.0031
Uptake of inhalational anesthetic =
solubility * CO * (PA-PV)
The insolubility of N2O causes the partial pressure to equilibrate rather quickly in the brain. Nitrous does not lose very much kinetic energy when entering the blood. True or false?
True
Potential error in volume measurement due to gas solubility in a water seal.
If there are a mixture of N20, O2 and N2 in a take surrounded by a large water seal, which gas would be lost to the water the most?
N20 since it is the most soluble in water. You will find increase of partial pressure of
also known as second gas effect
Solubility coefficient of N20 in oil:
1.4
Solubility coefficient of halothane in oil
224
______ is much more soluble than ______ in oil.
Thus what is a more potent anesthetic agent?
Halothane
N20
Halothane
Solubility of anesthetic agent in blood also known as the _____/____ coefficient for N20 is:
blood/gas coefficient
0.47
MAC is ____ _____ _____ in ____, at _____, at ____ atm.
minimum alveolar coefficient
percent
equilibrium
1
The MAC of a 20 y/o for sevo is ____.
2.6 %
The MAC decreases by ____ per decade increase.
- 50 y/o MAC
- 40 y/o MAC
- 30 y/o MAC
- 20 y/o MAC
0.2
- 2.0
- 2.2
- 2.4
- 2.6
What is the partial pressure of the anesthetic agent in the brain in Sevo at MAC?
15.2 mmHg
760 * 0.02
Anesthesia commences when a chemical substance reaches a certain molar concentration in the hydrophobic phase is known as the ____ ____ _____.
Also explains why anesthesia is produced by the partial pressure of the anesthetic agent in brain tissue.
Meyer-Overton Correlation
The more soluble the agents are in fat, the more potent they are as anesthetic agents, the _____ the MAC.
lower
MAC is isoflurane reaches a peak at ____-____ _____.
1-6 months
_____ solubility means you must dissolve a lot more to produce a change in partial pressure/concentration.
High
____ solubility in blood = fast induction and recovery.
low
_____ solubility in blood = slower induction and recovery.
High
Anything that increases delivery of anesthetic to the alveoli, thus _____partial pressure will ____anesthesia.
increasing
hasten
Anything that enhances removal from the lungs, increasing systemic uptake, will _____alveolar partial pressure and ____anesthesia.
lower
delay
The greater the concentration in inspired gas, the more _____ the induction
rapid
____ and ____ are more irritating.
isoflurane
desflurane
The greater the ventilation, the more anesthetic that is delivered to the lungs, the more ____ the induction.
This is ____ important with insoluble agents like ______ than with more soluble agents.
- rapid
- less
- desflurane
Hyperventilation does not increase anesthetic depth
______ agents go to the their inspired concentration in the alveoli very quickly.
The order of FA/FI of agents
Insoluble
N20, Des, Sevo, Iso, Halo
If cardiac output is ______: removes large quantities of gas from alveoli and lowers alveolar tension and delays equilibrium.
high
_____ total cardiac output generally slows the onset of general inhalation anesthesia.
Increasing
Tissue uptake is dependent on: (3)
and varies according to the amount of _____ present.
- blood flow
- gas tension
- blood/tissue coefficient
lipid
Uptake of anesthetic agent proceeds sequentially into 3 main compartments:
- vessel rich group
- muscle
- fat
Blood/gas partition coefficient of desflurane and nitrous (N20)
- 42
- 47
Blood/gas partition coefficient of sevoflurane
0.68
Blood/gas partition coefficient of isoflurane:
1.4
Potent agents are administered with N20 so that the potent agent will be delivered in increased amounts (concentration) to the alveoli as the nitrous oxide is absorbed by _____ blood is known as the ____ ____ ____.
N20 equilibrates so quickly so only stays true for 4-5 breaths. True or false?
pulmonary
Second Gas Effect
true
Occurs when nitrous oxide is administered in high concentrations during induction. Nitrous oxide is taken up rapidly and more gas rushes in to take its place, effectively increasing alveolar ventilation is known as _____ ____.
concentration effect
