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Is vapor pressure a function of volume temperature or pressure?
temperature
List the Vapor pressures:
Sevoflurane
Enflurane
Isorflurane
halothane
Desflurane
S: 170
E: 172
I: 240
H: 244
D: 669
If Enflurane is added to a flask of Oxygen, what is the % Enflurane and the % O2 in the flask above the liquid?
Partial pressure of Enflurane = 172
PP of O2 after Enf is added = 760-172 = 588
% O2 = 588/760 x 100 = 77%
%Enf = 172/760 x 100 = 22.6%
If desflurane is added to a flask of O2, what is the % Des and % O2 above theliquid?
PO2 after Des added = 760 - 669 = 91
%O2 = 91/760 x 100= 12%
%Des = 669/760 x 100 = 88%
if Isoflurane is added to a Sevoflurane vaporizer, what wil this do tho the delivered concnentrationof gas?
VP Iso = 240
VP of Sevo= 170
HLH = if a Higher vapor pressure agnet is placed in a vaporizer desigend for a Lower VP agent, then the concnetrationof agent deliverdd ot the pt will be Higher than the dial setting
what would happen if enflurane was added to a Halothane vaporizer?
the concentration delivered wiould be less than the dial setting
VP of Enf = 172
VP of Halothan = 244
LHL = if a Lower VP aganet is placed in a vaporizer desigend for a Higher VP, the concentration of agent deliverd will be Lower than the dial setting
What degree C is Desflurane heated to in its vaporizer and what does this do to its Partial pressure?
39 Degrees C.  VP at this temperature is 2 atmospheres (1500 mm Hg)
1 m mHg = ? cm H2O
1.36 cm H2O
1 atm = ? mm Hg = ? psi = ?kPa = ?bar
1 atm = 760 mmHg=14.7 psi = 101kPa = 1 bar
1 psi = ? mmHg
1 psi = 54 mmHg
Bourdon gauges measure ______pressures?
High pressures (cylinder pressures)
when the Bordon gauge reads 0, what does this mean?
the pressure in the cylinder is the same as atmospheric pressure (the bordon gauge measures pressure relative to atmospheric pressure, not the absolute pressure)
Law of LaPlace (for cylincers): T =
Applies to cylindrically shaped structures (tanks, bl vessels, left ventricle)
T = P x r
as a structure expands (increases its radius),the tension in the wall of the structure increases
Law of LaPlace (for spheres):T =?
T = (Pxr)/2
**How does the law of  LaPlace explain why smaller alveoli empty into larger alveoli causing atelectasis in patients with ARDS?
Law of LaPlace states that spheres have tension on the outside that is  independent of radius.  So, since the tension does not change with a change in radius.  With a small radius, the pressure inside the sphere will increase.  So, the small alveoli that are connected to large alveoli will have a tendency to collapse into larger alveoli.  The tension on the outside of both alveoli are the same, but the radius and the pressure inside are different.
*this is only true with ARDS b.c there is a deficiency in surfactant (usually this atetelectasis is prevented by surfactant)
How does the Law of LaPlace explain why small alveoi do not empty into large alveoli in hte normal lung?
since lungs have surfactant, this cuases tension to increase with an increase in radius.  since alveolar wall increase with increase in radius, the pressure inside the alveolar does not change.  This prevents it from collapsing into a connected alveolar with a smaller pressure (b/c they all have the same pressure inside)
**The property of a fluid that determines flow in Laminar flow is _______
Viscosity
Whose law explains Laminar flow?
Poiseuille's Law
F = ∏r4 ΔP/ 8ηL
Flow is directly proportional to the fourth power of the radius
According to Poiseuilles' Law, doubling the radius, will increase the flow how mcuh?
16 times
(2r)4 = 2x2x2x2r4 = 16r4
According to Poiseuille's law, when a radius of a tube is tripled, how does this affect the flow through the tube?
Increases the flow 81 times
when the radius of a tube is halved, how does this affect the flow?
if the radius is decreased by 1/3?
this will decrease the flow to 1/16th the original value
the flow will decrease to 1/81 of is original value
what has the most dramatic affect on laminar flow through a tube?
changing the radius
a polycythemic pt has high or low flow through blood vessels? why?
flow is decreased b/c their blood viscosity is increased
anemic pts have decreased viscosity and increased flow through vessels
when an bag on an IV pole is increaed in height, what does this do to flow? why?
this increased the flow b.c the hydrostatic pressure gradient is increased
Flow is directly proportional to the hydrostatic pressure gradient (inflow pressure minus outflow pressure)
if the needle gauge on an IV is decreased, what does this do to flow?
This increases flow b/c the smaller gauge needle has a larger diameter (radius); according to Poiseulles' Law, Flow is directly proportional to the radius (r4)
According to Poisuelle's Law, Resistance is:
inversely proportional to_____
Diretly proportional to______
R is inversely proportional to radius
R is directly proportional to viscosity and the length of the tube
List 4 ways flow can become turbulent
  • Velocity is high
  • Tube wall is rough (corrugated)
  • kinks, bends, narrowing or branches
  • fluid flows thorugh an orifice
If fluid is flowing though a tube that is angles, at what anlge does laminar flow become turbulent
if the angle is > 25°
what does the Reynold's number predicts?
Re = (vdp)/η
when flow through a cylindrical tube changes from laminar to turbulent
Reynold's number is directly proportianl to what 3 things?
  • fluid velocity (v)
  • fluid density (p)
  • tube diameter (d)
when Reynold's number exceeds ____, flow changes from laminar to turbulent
1500-2000
**when flow is turbulent _____ determines flow
density (not viscosity)
Flow is inversely proportional to density
why is Helium used medically for upper airway obstruciton?
b/c Helium is a gas wiht a low density and when there is an upper airway obstruction, flow is turbulent, so the less density fo the gas, the higher the flow will be (makes breathing easier)
Waht principle applies to the venturi effect?
Bernoulli's principle: when fluid flow thourhg a constricted region of a tube, the veolicity of flow increases and the lateral pressure decreases
the operation of the nebulizer is based on what?
venturi effect
jet ventilatior, and venturi O2 mask also
what does Henry's law do?
permits calculation of dissolved O2 and dissolved CO2 in the blood
the at of a gas that dissolves in a liquid is proportional to the partial pressure of the gas in the gas phase
HOw much does dissolved O2 increase when partial pressure of O2 increases form 100 mmHg to 500 mmHg?
100x.003 = .3 ml O2 per 100 ml bl
500 x .003 = 1.5 ml O2/100 ml blood
1.5 - .3 = 1.2 ml
It increases by 1.2 ml O2 per 100 ml blood
**How much O2 is dissolved if the FiO2 is 40%?
*multiply the inspired O2 by 5 to get the PaO2: 40 x 5 = 200 mmHg
Amt O2 dissolved = 200 x .003 = .6 ml O2/100 ml blood
State Boyle's Ideal Gas Law
P1V1 = P2V2
Pressure is inversely proportional to volume at a constant temperature
measurement of FRC by body plethysmography uses who's law?
Boyle's
an E cylinder of O2 has what pressure and what volume when full?
2100 psi
625 liters
when breathing spontaneously, intrapulmonary pressure ___ and volume ___
whose law?
Pressure falls and volume increases
Boyle's law
squeezing an ambu bag -- whose law applies?
boyle's law
sehn squeexing: decreased volume and increased pressure
State Charles Law

Give an application of it
V1/T1 = V2/T2

volume is directly proportional to the temperature at a constant pressure

Application: the cuff of an LMA expands wehn places in an autoclave
State Gay-Lussac's Ideal Gas Law
P1/T1 = P2/T2

pressure is directly proportional to temperature if volume is constant
State the Ideal Gas law
PV = nRT
n = moles of gas
R = universal gas constant
Absolute temperature, K =
K = 273 + °C
whose law permits us to calculate the partial pressure of a gas if the % concentration is known?
Dalton's law
multiply the % gas by the atmospheric pressure
in the atmosphere at sea level, what is the partial pressure of O2 and nitrogen?
O2 (21%) = 760 x .21 = 160 mmHg
N2 (79%) = 760 x .79 = 600 mmHg
what is the partial pressure of O2 in the mountain (atm 550 mmHg)?
O2 in the air = 21%
.21 x 550 = 116 mmHg
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