Pressure Flashcards

(137 cards)

1
Q

What is hydrostatic pressure?

A

Gravity pulling down the atoms and molecules stack around us

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2
Q

How is pressure measured?

A

Force per unit

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3
Q

What is “ideal gas laws?”

A

An understanding of the predictable behavior of gases under ideal conditions

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4
Q

What happens to pressure in a frozen “empty” bottle?

A

Pressure rises and volume drops

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5
Q

Is temperature and volume inversely proportional or directly proportional?

A

Inversely proportional

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6
Q

Jacques Alexandre Cesar Charles formula?

A

T=K*V
Temp in kelvin

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7
Q

If temperature goes up what happens to pressure?

A

It will rise as well

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8
Q

What does Boyles law assume?

A

Temperature is consistent

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9
Q

Joseph Louis Gay-Lussac law?

A

P=K*T

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10
Q

Is temperature and pressure directly proportional?

A

Yes

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11
Q

Carlo Avogadro law?

A

V/n= k

N= number of molecules

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12
Q

1 mole of gas occupies as much volume as any other mole of gas as long as?

A

Pressure and temp are held constant

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13
Q

What does STPD stand for?

A

Standard, Temperature, and Pressure Dry

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14
Q

Elements and measurements of “STPD?”

A

0 degrees Celsius
760mmHg
Ideal molar volume- 22.4L

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15
Q

Ideal molar volume for any gas?

A

22.4L

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16
Q

What is the point of the ideal molar volume?

A

A standard point from which to calculate density of a gas

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17
Q

Where does pressure come from?

A

Gas has:
mass
Takes up space
Compressible and expandable
Influenced by temp
Exerts pressure

Mass, volume, temperature all influence pressure

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18
Q

Combined ideal gas law?

A

P= nRT/V

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19
Q

What is the #1 mechanism of hypoxemia?

A

Low inhaled partial pressure of O2

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20
Q

Relationship between temperature and volume that follows Charles law?

A

They are directly related

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21
Q

Describe relationship between pressure and temperature that follows Gat-Lu’s sac law?

A

They are directly proportional

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22
Q

The relationship between gas and volume following Avogadro law?

A

Directly proportional

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23
Q

Percentage of nitrogen, carbon dioxide, and oxygen in the atmosphere?

A

N2-78%
O2-21%
CO2-0.03%

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24
Q

What happen to pressure, volume, and temperature if either changes?

A

Temp⬆️

pressure ⬆️

volume ⬇️

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25
Combined ideal gas law for change in a closed system formula?
P1V1/T1 = P2V2/T2
26
Do gases separate from heavy to light?
No, they exert their pressure equally
27
Does FiO2 change in altitudes?
No, partial pressure of the gases changes
28
Define critical temperature?
The temperature when liquid cannot resist becoming gas
29
Critical temperature vs. boiling point?
Boiling point can rise and fall given different atmospheric pressure Critical temperature is stable
30
Critical temperature of O2?
-183 Celsius
31
Critical temperature of nitrogen?
-147.1 Celsius
32
Critical temperature of water?
374 Celsius
33
Why is nitrogen and O2 true gases?
They stand above their critical temperature
34
Why isn’t water a true gas?
Water stands above it’s critical temperature Gaseous form is vapor and compressed becomes liquid water
35
What is “molecular” humidity?
Water vapor
36
What is “particulate” humility?
Mist, fog, aerosol (tiny droplets suspended in air)
37
What is boiling point?
Temperature When vapor pressure of liquid exceeds atmospheric pressure (Interplay between temperature and atmospheric pressure)
38
Explain boiling?
Atmospheric pressure pushes down on water surface As the temperature rises, it creates more kinetic energy which weakens bonds and leads to water releasing vaporization breaking through
39
Two methods of conversion from liquid to gas?
Boiling and evaporation
40
Two forces that influence evaporation?
Saturation Heat
41
What happens to the H2O capacity when temp drops?
Water Capacity drops relative humidity rises Absolute humidity drops
42
Formula for relative humidity?
Humidity content/ humidity capacity
43
Three quantifying measures for water content in the air?
Absolute humidity Relative humidity Partial pressure
44
Define absolute humidity?
The total weight of humidity in the air
45
Define relative humidity
The weight of water vapor in the air relative to how much the air can hold
46
How does a closed system create equilibrium?
Air becomes so saturated that molecules exchange.
47
From Fahrenheit to Celsius?
F - 32/1.8
48
Define BTPS?
Ideal qualities of water when it reaches Isothermic Saturation Boundary Body temperature= 37C Pressure= ATM Saturation= carrying water caper at full potential for temperature
49
What is the weight associated with BTPS conditions
Air needs 43.8mgH2O/L to be saturated
50
What is a humidity deficit?
The difference between the what content in the atmosphere and how much we need in the respiratory tract in mgH2O/L
51
Define dew point?
When the air reaches 100 percent saturation and has to release water Can occur in ventilators when temperature drops in tubing
52
Why is water pressure hard to calculate?
It has high variability because it come and goes
53
Conditions for STPD
0 Celsius 760mmHg 0% RH
54
Conditions for ATPD
? Celsius ? mmHg 0% RH
55
Conditions for ATPS?
? Celsius ? mmHg 100% RH
56
Second mechanism of hypoxemia?
Hypercarbia/hypoventilation
57
Mechanism of hypoxemia
Diffusion defect (thickness of membrane) Low inhaled partial pressure of O2 Hypoventilation
58
How is the concentration of O2 diffused into blood determined by two factors of Henry’s law?
Concentration of O2 in blood at STPD Pressure of O2 in gas
59
Four elements of Fick’s law that influence volume of gas diffusion?
Thickness of membrane Surface area Pressure gradient Volume of gas diffusing across membrane
60
Why is CO2 19x more soluble than O2?
A larger solubility coefficient A large carrying capacity in blood
61
Why does pascal’s principle not explain pressure in fluid bubbles of different sizes?
It assumes consistent volume Also, it doesn’t account for the opposing pressure of surface tension. smaller alveoli receive less flow than larger alveoli
62
According to LaPlace’s law, distending pressure and surface tension are? (Proportional)
Directly proportional
63
According to LaPlace’s law, distending pressure and radius are? (Proportional)
Inversely proportional
64
Explain how the result of Laplace law would be the flow of gas from small to large alveoli and eventually atelectasis?
Because the smaller alveoli have more pressure, the gases would flow to the larger alveoli. With a smaller radius, the alveoli would have more surface tension and collapsing pressure
65
Example of hydrostatic pressure in the body?
Blood Pressure
66
What is hydrostatic and osmotic pressures use in the body?
A force that drives blood forward yet holds it in the vessel
67
What is semi-permeability?
A membrane permeable to solvents but not solutes
68
Where does fluid go if sodium is high outside of the cell?
Fluid leaves cells (hypertonic)
69
Role of oncotic pressure in the cell?
Hold fluid in the cell
70
Frank-Starlings formula
J=k(Pc-Pi)-a(pi(c)-pi(i))
71
What does “a” represent in the Franks-Starling formula?
Ability hold protein (Albumin)
72
What does pi represent in the Frank-Starling formula?
Oncotic
73
What does “J” represent in the Frank-Starling formula?
Constant
74
What does “K” represent in the Frank-Starling formula?
How tight
75
Process by which pressure is generated by solvents moving across a semi-permeable membrane?
Osmotic pressure moves the solvent against atmospheric pressure and gravity to equal solute to solvent concentrations.
76
Describe the “proof” that pressure in semi-permeable membrane has been made?
When the solutes in the U-tube rise against hydrostatic pressure and gravity
77
Explain three key physiological derangement’s using Starlings Law?
Elevated P(c): pulmonary edema (transudative) Pi(c): low Albumin levels causing fluid in interstitial space Pi(I): high levels of proteins in the interstitium or alveoli can cause fluid accumulation
78
Inflammable medical gases?
Gases that are flammable are not generally used for medical purposes
79
Safety factors to assess for gases?
Does it support life? Is it combustible? Is it flammable?
80
What is relative density?
Density of gas relative to air
81
Volume of one mole of ideal gas at STPD?
22.4L
82
The importance of density to RTs?
Less dense gases for severe obstructive or restrictive AWs
83
How do you calculate density using molar volume?
Gram weight/22.4L
84
Why is solubility of importance to us?
Level of solubility tells us the ease at which the gas will dissolve into the capillaries
85
What is critical pressure?
Pressure required to keep a substance liquid at critical temperature
86
Physical qualities of air detectable by human senses?
Odorless Colorless Transparent Tasteless
87
Safety profile of air?
Non-flammable Supports combustion Supports life
88
Two big uses of medical air
To drive respiratory devices To blend with oxygen to achieve a desired FiO2
89
Basic physical qualities of oxygen detectable by human senses?
Odorless Colorless Transparent Tasteless
90
Safety profile of oxygen?
Non-flammable Supports combustion Supports life
91
Average partial pressure of oxygen at 760mmHg in (air, ISB, alveoli, arteries, tissue)
In air: 160mmHg At ISB:150mmHg In alveoli: 100-110mmHg In arteries: 80-100mmHg In the tissue: 10mmHg
92
How much seawater equals 1 atmosphere?
33ft of water
93
Four indications for hyperbaric therapy?
Rapid decrease in partial pressure of nitrogen (the bends) Wound healing Carbon monoxide toxicity Air embolism
94
Factor by which hemoglobin has increased affinity to carbon monoxide?
Structural fires Indoor charcoal fire Automobile exhaust 250x
95
Name two ways that hyperbaric O2 therapy treat CO?
Floods system and dissolving in blood Shortening half life
96
Wounding healing challenge that could respond to hyperbaric O2 therapy?
Non-healing wounds due to anaerobic bacteria
97
How does hyperbaric O2 therapy treat wound healing?
Flooding body with O2 can kill bacterium
98
How does hyperbaric therapy treat bends?
By raising the pressure, you can gradually lower it to reverse “the bends.”
99
Name the two ways we get oxygen?
Fractional distillation Molecular filtration
100
What is molecular filtration?
A vacuum draws air into a cylinder with crystallized zeolites Zeolites absorb nitrogen resulting in a lot of oxygen Afterwards decompressed zeolites release nitrogen to be used again
101
Describe fractional distillation
oxygen under pressure limiting kinetic energy drops temperature causing condensation and turning liquid
102
Percent of saline in blood
0.9% 135-145
103
Does oncotic pressure change?
No As hydrostatic pressure decreases, it becomes more influential
104
Laplace’s Law for a Sphere?
P= 2T/r
105
What is the body’s water capacity?
43.8
106
Physical qualities of CO2
Colorless Transparent Odorless to strong odor Tasteless or slightly acidic
107
Safety profile of CO2
Non-flammable Does not support combustion Does not support life
108
How is CO2 administered?
Carbogen: 90:10 95:5
109
Reasons to use CO2
Hiccups Atelectasis Anxiety-related hyperventilation Cerebrovascular condition
110
Physical qualities of helium?
Colorless Transparent Odorless Tasteless
111
Safety profile of helium?
Non-flammable Does not support combustion Does not support life
112
Name of mixture of helium and O2?
Heliox
113
Ratio of heliox?
80 H2:20 O2
114
Most commonly used application for heliox?
Large airway obstruction (Tumor growth)
115
What is the more controversial use of Heliox?
Smaller airway obstruction (Asthma exacerbation)
116
Physical properties of Nitric oxide?
Colorless Transparent Tasteless Slightly metallic odor
117
Safety profile of nitric oxide?
Non-flammable Does not support life Does support combustion
118
Patient population for nitric oxide?
To term and near-term neonatal Off label: adults
119
Mechanism of action for nitric oxide?
Cause vasodilation
120
What is the unit dose of nitric oxide?
20 parts per million
121
Why doesn’t nitric oxide affect the systemic system?
Because it dissipates rapidly so it doesn’t have time to impact the systemic system
122
Physical properties of nitrogen?
Colorless Transparent Odorless Tasteless
123
Safety profile for Nitrogen
Non-flammable Does not support combustion Does not support life
124
Medical uses of Nitrogen?
Powers pneumatic instruments in OR Used to create zero-point reference gas for O2 analyzers
125
Explain the conservation of energy
Total energy in a system remain constant (No gain or loss) Can change form (potential to kinetic)
126
Define flow?
The movement of a volume of fluid in a specific period of time
127
Flow units used in for the ventilator?
L/minute
128
Flow units used for respiratory calculations?
L/second
129
Ficks formula
VDgas=A/T x Dgas (p1-p2)
130
What does “A” represent ficks law
Surface area
131
What does “T” represent ficks law
Thickness of membrane
132
What does “Dgas” represent in ficks law
Diffusability of gas
133
What does p1-p2 represent in Ficks law
Pressure gradient
134
Uses of nitrogen
Power devices Creates zero point for O2 analyzers Test patients tolerance for altitudes Helps deliver different concentrations of oxygen
135
Bernoulli principle applications in Venturi
Bernoulli steady flow in a closed system Venturi: steady flow in open system
136
Why is CO2 used for laparoscopic surgery
Will be absorbed by body Won’t support combustion if electrocautery
137
Why is CO2 used for colonoscopy
Reduces patients discomfort after procedure