mini study guide gas laws Flashcards
what is the equation for Charle’s Law?
Volume/ Temperature
V1/T1= V2/T2
as volume increases, temperature ______
increases
as volume decreases, temperature ______
decreases
give an example of charles law in the anesthesia practice?
A LMA ruptures in an autoclave
so according to Charle’s law, there is a ____ relationship between volume and temperature
direct
Describe Boyles Law?
there is an inverse relationship between pressure and volume
P1V1=P2V2
as pressure increases, the volume ______
decreases
as pressure ______, as volume increases
decreases
give an example of of boyles law in anesthesia?
diaphragm contraction increases tidal volume
squeezing an ambu bag
describe gay-lussac’s law?
direct relationship of pressure and temperature
as temperature increases, pressure ____
increases
as temperature decreases, pressure _______
decreases
give an example of gay lussacs law?
oxygen tank explodes in a heated environment, because pressure increases
what is avogadro’s law?
equal volumes of gases under the same conditions have equal number of molecules.
so as the number of mols increase, the volume ____
increases
remember amount for the avogadros law is measured in?
mols
ideal gas law is described?
PV=nrT
n and r are constant
n= number of moles
r= universal gas constant
what is the only constant unit of measurement in temperature scales is _________
kelvin
what is the actual equation for Boyles Law?
P1 x V1 = P2 x V2
what is the actual equation for Charles law?
V1/T1 = V2/T2
What is the actual equation for Gay-Lussac’s Law?
P1/T1 = P2/T2
if you had to reduce the ideal gas law down, what would the formula be?
P=T/V
pneumatic bellow function, would be an example of what gas law?
Boyles Law
Using the bourdon pressure gauge to calculate how much O2 is left in a cylinder (assumes a given flow rate) is an example of what gas law?
boyles Law
what is the number for the r in the ideal gas law?
constant 0.0821 liter-atm/k/mole
describe dalton’s law of partial pressures
the total pressure is equal to the sum of the partial pressures exerted by each gas in the mixture
what is the equation for daltons law of partial pressure?
Ptotal= Pgauge + Patmosphere
what law allows you to calculate the partial pressure of an unmeasured gas?
Daltons Law
what is the total pressure equal to in Daltons Law?
atmospheric pressure
how do you convert partial pressure to volumes percent?
partial pressure divided by the total pressure multiplied that product by 100
volumes percent is a way to communicate a solutions _______
concentration
how do you convert a volumes percent to a partial pressure?
you would multiple the volume percent by the atmospheric pressure (AKA the total pressure)
so if you had 2% sevo, you would do 0.02x760=15.2 mmHg of sevo for a partial pressure
so what would the partial pressure be for nitrous oxide of 2L/min if the total gas flow is 3L/min?if the atmospheric pressure is 650 mmHg?
2/3=0.66x650=429 mmHg
what is henry’s Law? what must be constant? what type of relationship present?
the amount of gas that dissolves in a solution is directly proportional to the partial pressure of that gas over the solution. the temperature must be constant.
the higher the partial pressure of a gas, what happens to the solubility?
increases
how does temperature affect solubility? what is the relationship?
solubility decreases with increased temperature
inverse relationship
each gas has its own _____ coefficient
solubility
define solubility?
how easily the gas can be put into a solution
what is the solubility coefficient for oxygen?
0.003 mL/dL/mmHg
what is the solubility coefficient for carbon dioxide?
0.067 mL/dL/mmHg
Carbon dioxide is ___ times more soluble than oxygen
20 times
describe how solubility is affected for the anesthesia provider with a hypothermic patient?
anesthetic emergence is prolonged in the hypothermic patient because the solubility of the gas is increased, so less of it leaves the body per unit of time
how can you calculate oxygen delivery?
by multiplying the PaO2 by the oxygen solubility coefficient (0.003), allowing us to calculate how much oxygen is dissolved in the blood
how could you apply henry’s law to a hypoxic patient?
increase FIO2 or place patient in the hyperbaric chamber, both of which will increase the partial pressure of oxygen delivered, thereby increasing the solubility of the oxygen.
if you hasten the transfer of a volatile anesthetic at the alveolocapillary interface, you can increase the transfer into the brain, this process is called?
overpressuring the vaporizer
describe grahams law?
the rate of gas diffusion is inversely proportional to the square root of its molecular weight
fick’s law describes?
the transfer rate of gas through a tissue medium
the rate of transfer of a gas is directly proportional to?
partial pressure difference (driving force)
diffusion coefficient (solubility)
membrane surface area
rate of transfer of a gas is inversely proportional to?
membrane thickness
molecular weight
what two laws are incorporated into Ficks Equation?
henrys law
grahams law
what law would apply with diffusion hypoxia?
Fick’s Law of Diffusion
what law would apply when a COPD patient with reduced alveolar surface area, has a slow inhalation induction?
ficks law
what law applies for drug transfer across the placenta?
fick’s law
Flow is defined as the movement of per unit of time?
electricity, fluid or air per unit of time
describe Ohm’s Law? describe the relationships.
the current passing through a conductor is directly proportional to the voltage and inversely proportional to the resistance.
voltage is known as the driving pressure, or what hemodynamic term?
blood pressure
the current is known as? or the hemodynamic term?
flow
cardiac output
the impedance is known as? hemodynamic term?
resistance
SVR
what is the equation for ohm’s law?
I= V/R I= electric current v= voltage difference r= resistance
or can be Flow/ pressure gradient/resistance
Poiseuilles Law describe it? incorporates what?
Ohm’s law that incorporates vessel diameter, viscosity, tube length
as the diameter of a tube gets smaller, what happens to the resistance and why?
the resistance to flow is increased because a greater proportion of the fluid is in contact with the wall of the tube.
what is the equation for flow if it is laminar? then give the simplified equation?
πr4(P2 - P1) / viscosity x 8 x length
what is the real equation for Poiseuille’s Law?
π x R4 x change in pressure/ 8 x viscosity x length of tube
what exhibits the greatest impact on flow?
radius of the tube
viscosity is the result of ?
friction from intermolecular forces as a fluid passes through a tube
A fluids viscosity is inversely proportonate to its ________.
temperature
Decreased temperature increases _________ and _________.
viscosity and resistance
name 4 ways you can increase the speed of RBC delivery using Poiseuilles Law?
increase the radius with a large bore IV
increase the pressure gradiant with a pressure bag and/or increase the height on the IV pole
decrease viscosity by diluting the blood with 0.9% NaCl and/or running it through a fluid warmer
Decrease the length by not using longer tubing than you really need.
What is related to the thickness of a fluid?
viscosity
the greater the viscosity, the less easily _____ slide past one another and the more _____ it is to get the fluid moving and keep it moving.
molecules
difficult
____ is the percentage of RBC in the total blood volume
HCT
what lab value affects the blood viscosity and therefore the resistance to flow.
HCT
if you double the radius of the tube, you will increase the flow by?
16 times the original flow
