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Anesthesia Final3


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Gauge pressure vs absolute pressure:
P(absolute)= P(gauge) + P (atm)
SI unit of pressure
pascal (Pa)
pressure of one newton acting over one square meter
one pascal (1 Pa)
approximate atmospheric pressure at sea level
1 bar 100 kPa 760 mmHg 760 Torr 14.5 psi 1 atm
what is the formula for pressure?
P = f/a where P = pressure f = force a = area
type of flow in which fluid has no eddies or turbulence
One mole of any gas at STP occupies what volume?
22.4 L
Molec wt of N2O
Hagen-Poiseuille equation
Q = (Ϭ P d^4) / (128 η l) where Q = flow Ϭ = 3.14... P = pressure d^4 = tube diameter raised to the 4th power η = viscosity l = tube length
equation which describes the effect of pressure, tube length/diameter, and viscosity on laminar flow
Hagen-Poiseuille equation
what effect does surfactant have on Laplace's Law
It reverses it. Surface tension= r/2T
Reynolds number equation
Reynolds number = vρd/η where v = linear velocity ρ = density d = tube diameter η = viscosity
the fluid property that is involved in turbulent flow is:
This fluid property is involved in laminar flow:
type of flow usual in lower respiratory tract
type of flow usual in upper respiratory tract
Laplace's law for sphere
P = 2 X T / r where P = pressure T = surface tension r = radius
Molec wt of He2
fall of pressure after a constriction in a tube
Bernoulli effect/venturi effect
tube which takes advantage of Bernoulli effect to entrain gases or nebulize liquids
Venturi tube
tendency of stream of fluid or gas to continue to flow along a convex surface
Coanda effect
states that at constant temperature the volume of a given mass of gas varies inversely with the pressure
Boyle's Law
What is entonox?
50/50% O2/N20 mix
states that at constant pressure the volume of a given mass of gas varies directly with the temperature
Charles' Law
Formula to convert F to C:
Tc= 5/9 (F-32)
statest that at constant volume the pressure of a given mass of gas varies directly with the temperature
Third Perfect Gas Law OR Gay Lussac's Law
Formula to convert C to F:
Tf= (9/5 C) +32
a change in the volume and pressure of the contents of a system without exchange of heat between the system and its surroundings
adiabatic change
states that in a mixture of gases the pressure exerted by each gas is the same as that which it would exert if it alone occupied the container
Dalton's Law of Partial Pressures
states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules
Avogadro's hypothesis
Avogadro's number
6.022 X 10^23
Universal Gas Constant equation
PV = nRT where P = pressure V = volume n = moles R = constant T = temperature
temperature above which a gas cannot be liquified however much pressure is applied
critical temperature
the pressure at which a vapour will liquify, in a substance below it's critical temperature
critical pressure
critical temperature at which a gas mixture may separate into its constituents
pseudocritical temperature
process in which the rate of change of a quantity at any time is proportional to the quantity at that time
exponential process
the time a process would have been complete had the initial rate of change continued
time constant
molec wt of N2
partial pressure of a vapor in a closed container and at equilibrium with the liquid phase
vapor pressure
states that at a particular temperature the amount of a gas dissolved in a liquid is directly proportional to the partial pressure of the gas in equilibrium with the liquid
Henry's Law
the volume of a gas which dissolves in one unit volume of a liquid at the temperature concerned
Ostwald solubility coefficient
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
another word for partial pressure for gases in a solution
the physical state of a substance above it's critical temperature
a gas
a substance in its gaseous phase below its critical temperature
a vapor
Dalton's Law equation
Pmixture = P1 + P2 + P3...
fall of alveolar oxygen concentration as a result of the dilution of alveolar oxygen by excretion of nitrous oxide
diffusion hypoxia
increase in concentration (partial pressure) of a gas in the alveoli when a more soluble gas diffuses quickly into the bloodstream - results in increased rate of diffusion for the second gas
second gas effect
point at which 50% of patients cease to move in response to a stimulus
MAC (minimum alveolar concentration)
rate of diffusion of a substance across a surface or membrane is proportional to the concentration gradient
Fick's Law
states that the rate of diffusion of a gas is inversely proportional to the square root of its molecular weight
Graham's Law
states that depression or reduction of vapor pressure of a solvent is proportional to the molar concentration of the solute
Raoult's Law
a mixture which vaporizes in the same proportions as the volume concentrations of the components in solution
pathway with length greater than width
pathway with width greater than length
point at which increased pressure results in turbulent flow but below which flow is laminar
critical point
variable orifice flowmeter
Thorpe tube
property of He which makes it useful for decreasing resistance to flow through narrowed lower airways
low density
force per area of molecules in a liquid as they interface with the gas above it
vapor pressure
to determine time left on a cylinder of nitrous oxide, you must determine the volume of gas available from both...
the liquid phase and the vapor phase
unit of measure for osmotic activity
6.02 X 10^23 particles of dissolved solute that cannot diffuse through a semipermeable membrane
1 osmole
pressure exerted by 1 gmw of a nonionizing, nondiffusible solute in 22.4L of water
1 atm
pressure exerted by 1gmw of a monovalent, ionizing, nondiffusible solute in 22.4L of water
2 atm
states that even in isolation from the environment, a gas cools when expanded and warms when compressed
Poisson adiabatic equation
Which of the following does NOT affect rate of laminar flow? pressure gradient, fluid viscosity, tube length, fluid density, tube diameter
pressure gradient.

reynolds # is:
(velocity x density x diameter)/(visc x length)
At low rates of flow, the orifice of a variable orifice flowmeter is more like what?
a tube
tendency toward turbulence increases when this fluid property is increased
tendency toward turbulence decreases when this fluid property is increased
As tube diameter is doubled, rate of flow _________ by a factor of _____.
increases, 16
As tube length is halved, rate of flow ____________ by a factor of _____.
decreases, 2
molec wt of H2
molec wt of CO2:
critical temp for N2O
36.5 C
What is weight?
A function of the effect of gravity on mass.
Explain relationship of densities of H2O to Hg:
Hg is 13.6 times more dense than H2O.
1kPa = 7.5 mmHg
1kPa = 10.2 CM (102 mm)H2O
what is a racemic mixture:
an optically neutral mixture of 2 stereoisomers that has different properties than if it were all one stereoisomer alone.
hydrogen bonds:
Intermolecular attraction caused by ionic (unequal) sharing of electrons on water molecules; causes a dipolar molecule.
Vanderwaals Forces:
weak interatomic attractions caused when two uncharged atoms are in close proximity due to random variability of electron location around the atoms. Plays a key role in DNA and protein structure and folding.
What is an isotope:
All similar atoms have same # of protons and electrons. Isotopes have different # of neutrons.
Convert C to Kelvin:
K = C + 273
What are ionic bonds?
Highly electronegative atom *unequally shares electrons with a less EN atom.
What is a covalent bond?
Equal sharing of electron(s) between atoms.
What is the critical temp of O2?
-118 C
What does the solubility coefficient of a gas mean?
the #cc of gas that will disolve in a unit/vol of liquid at a stated temp & pressure.

Ostwald Solubility Coefficient
What is a mole measuring?
the number of atoms in one gram molecular wt of substance.
What is a stereoisomer?
Has same molecular "ingredients" but is arranged differently. May have different physical or chemical properties.
Define vapour pressure:
the pressure exerted by the molecules in a liquid as they interface with the surface of the liquid.
What is the vapor pressure of H2O?
When looking at a Bourdon gauge, how can you determine Psia?
add the Psig of the gauge to the Psia (14.7psi at sea level).
What is the formula for an exponential process?
y=x^2. or y=k^x (variable exponential process)
How much of of the original amount of substance is left after one time constant if the process is a true y=x^2 negative exponential process?
37% of original
What is an example of a "washout curve" / negative exponential process?
thermodilution measurement of cardiac output.
What is an example of a positive exponential process?
Bacterial or tumor growth.
What is a build up exponential process and how does it differ from positive exponential process? Give an example:
The rate of change is initially rapid but slows toward the end. An example is lung filling.
Why is Ostwald's solubility coefficient more useful for CRNAs?
It is given at a known (practical) temp and is independent of pressure.
Explain why a highly soluble anesthetic like ether is less potent than N2O which is (relatively)less soluble:
The ether crosses the alveocap mem instantly and does not allow alveolar partial pressure of ether to develop. The ether is highly soluble so it wants to stay in the blood and doesn't move into the brain tissue readily. The N20, on the other hand, rapidly builds up a high alveolar pressure gradient and begins "forcing" the N2) into the blood even though it isn't as soluble and doesn't want to be there. Because it isn't as soluble, it "pops" out of solution into the brain tissue readily. Hence, it is more potent.
Explain Ficks law in laymans terms:
the rate of diffusion of a substance across a membrane is proportional to the concentration gradient: this means that if you have 10 marbles and 5 will move across a membrane in one minute, if you have 20 marbles then 10 will move across in one minute. It's just a function of how much you have available to move at any one time.
What does Raoult's Law say?
the depression or reduction of vapour pressure of a *SOLVENT is proportional to the molar concentration of the *SOLUTE.
Explain Raoult's Law now in laymans terms:
the more salt you add to a bucket of water, the less water vapour in equilibrium over the surface of the water. That's because the salt molecules interfere with the water molecules interacting with the surface. Makes sense, eh? (Gary!)
What is "work" (physics)?
it is when "the point of application of a force moves in the direction of the force."
What is the SI unit of work?
one Joule = N/m
What is the definition of "power"?
Power is the *rate of work.
What is the SI unit of power?
the watt.

1 W = 1 J/sec
What does osmolality tell you?
it is the unit of measure for osmotic activity, so tells you the pull that it has on water.
How much of a substance would make a 1 Osm concentration?
One Avogadro's # of that molecule = 1 Osm.
In 1 L of solution.
You put 1 Gram*atomic wt of glucose in a liter of H2O. What is it's osmotic pressure?
1 osm/L
You put 1 Gram*atomic wt of NaCl in a liter H2O. What is the osmotic pressure?
2 osm/L (the NaCl seperates into Na and Cl).
What is the rule of thumb for calculating osmotic pressure?
at zero degrees Celcius 1 GMW of any substance dissolved in 22.4 L of water will exert a pressure of 1 atm.

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