Chemistry of Anesthetic Agents Flashcards
1
Q
What is energy defined as in chemistry and physics?
A
The capacity to do work.
2
Q
What does the Law of Energy Conservation state?
A
The amount of energy in the universe is constant and is constantly being converted from one form to another.
3
Q
True or False: Energy can be gained or lost.
A
False, it only changes forms
4
Q
How can we alternatively describe energy?
A
Energy is neither created nor destroyed; it is converted to other kinds of energy.
5
Q
What is the most basic form of energy?
A
Heat.
6
Q
How does heat affect kinetic energy?
A
Heat can contribute to the amount of kinetic energy that a substance has.
7
Q
Define kinetic energy.
A
Energy in motion.
8
Q
What happens to molecular motion as energy is added (heat) and as energy is removed (Cooled)?
A
Molecular motion increases as energy is added and decreases as energy is removed.
9
Q
What is latent energy?
A
Stored energy for later use.
latent = later
10
Q
Give an example of latent energy.
A
A stretched rubber band
Water that has built up behind a dam
11
Q
What happens to kinetic energy when a ball is thrown upwards?
A
The kinetic energy decreases as the ball travels upward.
12
Q
What is the kinetic energy of a ball at the top of its flight?
A
Zero.
13
Q
What is the relationship between latent energy and the ball-ground system?
A
Latent energy is large when the ball is high and low when close to the ground.
14
Q
What occurs when a gas particle encounters a container wall?
A
Momentum is transferred to the wall.
15
Q
Define pressure
A
Pressure = Force / Area.
16
Q
____ Is the change in momentum per unit of time
A
Force
17
Q
___ is the conversion of energy.
A
Pressure
18
Q
Fill in the blank: Pressure is defined as _______.
A
Force per unit of area.
19
Q
True or False: Kinetic energy is transferred to the walls of the container to produce measurement of pressure.
A
True.
20
Q
What are the fundamental building blocks of matter?
A
Atoms
Atoms are the smallest units of matter, comprised of protons, neutrons, and electrons.
21
Q
What determines the atomic number of an atom?
A
The number of protons
Atoms cannot gain or lose protons.
22
Q
What particles make up an atom?
A
- Protons
- Neutrons
- Electrons
23
Q
Can atoms gain or lose protons?
A
False
Atoms can only add or lose electrons and neutrons.
24
Q
What forms when atoms combine?
A
Molecules
25
____are combinations of two or more atoms held together by chemical bonds.
Molecules
26
What is the smallest particle of a pure substance that retains its composition and chemical properties?
Molecule
## Footnote
A molecule is not infinitely divisible into smaller fractions of the same substance.
27
Give an example of a pure substance that can be best understood as composed of networks or aggregates.
Metals
## Footnote
Metals are considered as an electron sea, with motion happening at all times.
28
What is the smallest unit of an element?
Atom
## Footnote
Examples of elements include hydrogen and carbon.
29
What is the smallest unit of a compound?
Molecule
## Footnote
Examples of compounds include water and carbon dioxide.
30
name in order the largest to smallest units:
atoms
molecules
elements or compounds
31
How are elements composed?
Of like atoms
## Footnote
Compounds can be composed of different types of atoms.
32
What defines a solid?
Has a definite volume and a definite mass
## Footnote
A solid has a definite shape and is non-compressible.
33
What is a characteristic of liquids?
Have no definite shape but have size (volume they occupy)
## Footnote
Liquids take the shape of their container and are non-compressible.
34
What is a property of gases?
Have no definite shape or size
## Footnote
Gases are spontaneous in expansion and are compressible.
35
What is the composition of the air around us?
21% oxygen, 78% nitrogen, rest is CO2 and others
36
What is a non-Newtonian fluid?
A fluid that does not follow Newton's law of viscosity
## Footnote
Its viscosity changes when subjected to force, e.g., ketchup becomes runnier when shaken.
37
What are aerogels?
Synthetic porous ultralight materials
## Footnote
Derived from gels where the liquid component is replaced with gas.
38
What holds all phases of matter together?
Intermolecular forces
## Footnote
These forces provide the backbone for the shape of the substance.
39
What must happen to energy to change phases of matter?
Energy must be added or taken away
## Footnote
Heating a liquid loosens intermolecular bonds to convert it into gas.
40
What are van der Waals forces?
Attractions between atoms, molecules, and surfaces
## Footnote
They differ from covalent and ionic bonds and are caused by fluctuating polarizations of nearby particles.
41
Electrons exist in ___ that relate to the distance from the nucleus.
energy levels
42
How many electrons can the 1st energy level hold?
2 electrons.
43
give an example of a 1st level electron
hydrogen and helium
44
How many electrons can the 2nd energy level hold?
8 electrons.
45
How many electrons can the 3rd energy level hold?
18 electrons.
46
What do valence level electrons seek?
To become more stable by maximally filling the valence level.
47
What is the next best scenario for valence electrons if they cannot be fully filled?
Having eight electrons in the outer energy level.
48
What is the Octet Rule?
Atoms lose, gain, or share electrons to have 8 valence electrons.
49
What are valence level electrons?
Electrons in the outermost energy level of an atom.
50
When are atoms most stable?
When energy levels are completely full.
51
What is the significance of the periodic table?
It classifies elements based on their properties and atomic numbers.
52
What does the Periodic Law state?
The properties of elements are periodic functions of their atomic number.
53
Where are Representative elements located on the periodic table?
In the two 'high rise' portions at the left and right extremes.
54
How are Representative elements denoted?
By the letter 'a' at the end of their group number.
55
Where are Transition elements found on the periodic table?
In the 'connector' group between the two Representative groups.
56
How are Transition elements denoted?
By the letter 'b' at the end of their group numbers.
57
What information does each square on the periodic table provide?
Atomic number, atomic mass number, and element information.
58
What is the atomic mass of water?
18.
59
What is the atomic mass of a single oxygen molecule?
32.
60
name the atomic number and atomic mass number of:
Hydrogen-
Carbon-
Nitrogen-
Oxygen-
1, 1
6, 12
7,14
8,16
61
What is Atomic Weight?
The weight of each individual atom.
62
What is Molecular Weight?
The sum of all of the atomic weights of the atoms that compose a compound.
63
What is the gram molecular weight?
When molecular weight is expressed in grams.
64
Define a Mole.
An amount of substance that contains exactly as many particles as exactly 12 grams of carbon-12.
65
How many molecules, particles, or atoms are in one mole?
6.023 x 10^23.
66
True or False: A mole of hydrogen weighs the same as a mole of H2O.
False.
67
What is an electrolyte?
A substance that dissolves in water to give a solution charged particles to conduct electricity.
68
What is a non-electrolyte?
A substance that dissolves in a solution and no charged particles are produced, therefore the solution cannot conduct electricity.
69
what are the basis of human life and a corner stone of how and why many of the drugs that we introduce to our patients work?
electrolytes
70
What types of compounds are usually electrolytes?
Ionic compounds that readily dissolve in water.
71
What primarily determines how molecules interact with one another?
Intermolecular forces.
72
What are intermolecular forces?
Forces that arise because of the attraction of opposite charges between molecules.
73
What impacts the macroscopic properties of a sample?
Intermolecular forces.
74
List some examples of properties affected by intermolecular forces.
* The state of matter under a given set of conditions
* The tendency of a liquid to evaporate
* The solubility of a material in water.
75
What is the physical process responsible for the attractive interaction between atoms and/or molecules?
Chemical bonding.
76
What is the overarching driving force in the formation of chemical bonds?
The octet rule.
77
What term refers to the electron-attracting power of each atom?
Electronegativity.
78
Which atom has the highest electronegativity?
Fluorine.
79
What is the relationship between electronegativity and bond strength?
As electronegativity increases, the strength of the bond between two atoms increases.
80
True/ false: The ability of fluorine to form strong bonds is key for the formation of stable less flammable anesthetic vapors
true
81
how can you find out the electronegativty of an element?
count the flourines!
82
What is an Ion?
An atom or group of atoms with a charge
## Footnote
Ions can be either positively or negatively charged based on electron gain or loss.
83
What happens when an atom loses an electron?
It becomes positively charged and is known as a Cation
## Footnote
Positively charged ions are attracted to negatively charged ions.
84
What happens when an atom gains an electron?
It becomes negatively charged and is known as an Anion
## Footnote
Negatively charged ions can couple with cations to form compounds.
85
What is a compound?
A substance formed when a positively charged ion couples with a negatively charged ion
## Footnote
Example: Na+ + Cl- = NaCl.
86
How are ionic compounds held together?
By ionic bonds, which are the attraction of oppositely charged ions
## Footnote
This results in the formation of crystalline lattices in solid-state.
87
What is the biological activity of charged drugs?
Drugs with a '+' or '-' charge usually cannot cross biological barriers
## Footnote
They are considered polar compounds and are easily excreted by the kidneys.
88
a ___ drug is considered a polar compound
charged
89
What can disrupt the Blood Brain Barrier?
Acute hypertension, osmotic shock, disease, tumor, trauma, irradiation, ischemia
## Footnote
These factors can allow charged drugs to cross biological barriers.
90
what form are polar compounds said to be in? and waht does that mean
they are in their water form or urine form and can easily be excreted by the kidney
91
What are Neuromuscular Blocking agents?
Ionized drugs that work on motor endplate receptors at the neuromuscular junction
## Footnote
They should not enter the central nervous system.
92
besides NMBA, what other drugs cause muscle flaccidity but does cross a biological barrier?
local anesthetics
93
What type of drugs can cross biological barriers?
Non-Ionized drugs, which do not have a charge
## Footnote
These are considered lipid compounds and are not easily excreted by the kidneys.
94
Give examples of non-ionized drugs.
Atropine and Scopolamine
## Footnote
Both can cross biological barriers and have CNS side effects.
95
What is Glycopyrrolate?
An ionized drug that is completely ionized at physiological pH values
## Footnote
It is soluble in water and alcohol, and is not easily excreted.
96
What is the significance of a drug being ionized?
It cannot cross biological barriers easily and is quickly excreted
## Footnote
Ionized drugs typically have a short duration of action.
97
Fill in the blank: Drugs that do not contain either a +/- charge are considered _______.
Lipid compounds
98
True or False: Polar compounds are said to be in their 'water or urine form'.
True
99
Which crosses biological barriers": ioninzed or un-ionized
non-ionized (un-ionized)
100
which is considered lipid compounds: ionized or un-ionized
un-ionized
101
What are the synonymous terms related to ionization for lipid soluble substances?
Lipid soluble, nonpolar, un-ionized, physiologically/pharmacologically active
## Footnote
These terms indicate the active state of substances in the body.
102
What are the synonymous terms related to ionization for water soluble substances?
Water soluble, polar, ionized, excretable, physiologically/pharmacologically inactive
## Footnote
These terms indicate the inactive state of substances in the body.
103
Define ionic bonding.
Bonding of 2-elements together by the oxidation of one element and the reduction of the other
## Footnote
Oxidation involves giving up an electron, while reduction involves gaining an electron.
104
Provide an example of ionic bonding.
Na+ + Cl- = NaCl
## Footnote
This represents the formation of sodium chloride through ionic bonding.
105
What is the maximum number of electrons that the innermost shell can hold?
2
## Footnote
The first electron shell can hold a maximum of two electrons.
106
What is the maximum number of electrons that the second shell can hold?
8
## Footnote
The second electron shell can hold a maximum of eight electrons.
107
What defines ionic compounds?
Combination of a cation and an anion
## Footnote
Ionic compounds are commonly referred to as 'salts'.
108
How is the degree of ionic bonding determined?
By the electronegative difference between the two atoms
## Footnote
A greater difference leads to a stronger bond.
109
What is the physical state of virtually every ionic compound at room temperature?
Solid
## Footnote
Ionic compounds typically exist as solids under standard conditions.
110
the greater difference between the 2 atoms, the more or less likely the two atoms will be attracted to each other and form a bond?
more likley
111
how is the strength of a bond measured?
by how much energy is required to break it
112
What happens to ionic compounds when melted?
They consist of mobile ions floating around each other
## Footnote
Ionic melts can conduct electricity due to the presence of free-moving ions.
113
List the molecular bonds in decreasing order of strength.
* Covalent
* Ionic
* Polar Covalent
* Van der Waals
## Footnote
This hierarchy shows the relative strength of different types of bonds.
114
What characterizes covalent bonding?
Sharing of one or more pairs of electrons between two molecular structures
## Footnote
This sharing leads to mutual attraction that holds the molecules together.
115
What is a polar covalent bond?
A bond between atoms of different elements where electrons are not shared equally
## Footnote
This results in partial positive and negative charges on the atoms.
116
Provide an example of a nonpolar covalent bond.
H2, O2, N2, F2, Cl2, Br2, I2
## Footnote
These are diatomic molecules where electrons are shared evenly.
117
What occurs in a polar covalent bond between carbon and oxygen?
Oxygen appears slightly negatively charged, while carbon appears slightly positively charged
## Footnote
This results from the electronegativity difference between the two elements.
118
Are covalent bonds electronegatively neutral?
No
## Footnote
Covalent bonds can have a net charge that could be either '+' or '-' depending on the atoms involved.
119
in short, which bond is the sharing of electrons vs transfer of electrons?
sharing- covalent
transfer- ionic
120
How does Arrhenius define acids?
A species that increases the hydronium ion (H3O+) concentration in an aqueous solution
121
How does Arrhenius define bases?
A species that increases the hydroxide ion (OH-) concentration in an aqueous solution
122
What theory states that Ionic compounds separate or split into smaller particles (ions or radicals) usually in a reversible manner
the A-rhe-ni-us theory of Ionic Dissociation
123
According to BrØnsted's definition, what is an acid?
A species that donates a hydrogen ion (H+) to a base
124
According to BrØnsted's definition, what is a base?
A species that accepts a hydrogen ion (H+) from an acid
125
What is another name for the donated hydrogen (H+) ion?
Naked Proton (aka Protium)
126
What determines how active a substance is in its environment?
How quickly a substance gives up a H+ and how readily it accepts a H+
127
what kind of bond is water?
covalent
128
What is osmosis?
The movement of water molecules from an area of high concentration (of water) to an area of low concentration (of water)
129
A substance or compound (usually in a lesser amount) that is dissolved in another substance (often a liquid).
a solute
130
A liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution.
solvent
131
The pressure that must be applied to the side with more solute to prevent a net movement of water down a concentration gradient
osmotic pressure
132
What is the difference between osmolarity and osmolality?
Osmolarity is the number of osmoles per liter of solvent; osmolality is the number of osmoles per kg of solvent
133
what is the only thing osmotic pressure is dependent upon?
the # of non-diffusable solut particles
134
true or false: osmosis is reversible
false, diffusion is
135
What is tonicity?
The effect a solution has on cell volume
136
What happens to cells in isotonic solutions?
No effect on cell volume
137
What do hypotonic solutions cause to cells?
Cells will swell and possibly lyse
138
What do hypertonic solutions cause to cells?
Cells will shrink (crenation)
139
What is one Osmole equivalent to?
One mole of a non-dissociable substance
## Footnote
Non-dissociable substances cannot break down any further in a solution.
140
How many osmoles does 1 mole of NaCl produce in solution?
2 osmoles
## Footnote
This is because NaCl produces two ionic species: Na+ and Cl-.
141
How many osmoles does 1 mole of CaCl2 produce in solution?
3 osmoles
## Footnote
CaCl2 dissociates into Ca+ and two Cl- ions.
142
an osmole is The amount of osmotically active particles that when dissolved in 22.4L of solvent at ___ degrees Celsius exerts an osmotic pressure of 1 atmosphere
0
143
What osmotic pressure difference is caused by 1 milliosmole per liter between two solutions?
19.3 mmHg
## Footnote
This small difference is significant in fluid shifts within the body.
144
What direction does water flow during osmosis?
From the solution with lower solute concentration to the solution with higher solute concentration
## Footnote
Water moves in response to differences in molarity across a membrane.
145
What determines osmotic pressure?
The number of non-diffusible solute particles
## Footnote
The size or weight of the particles does not influence osmotic pressure.
146
What is the average molecular weight of Dextran 40?
40,000
## Footnote
This is relevant to its role in generating osmotic pressure.
147
What is hydrolysis in the context of drug metabolism?
A water molecule is added to a drug molecule rendering it a polar molecule
## Footnote
This process often involves breaking ester bonds.
148
Which enzyme system is often not involved in the hydrolysis of drugs?
Cytochrome P-450 enzyme system
## Footnote
Other enzymes like plasma cholinesterase are responsible for this process.
149
Fill in the blank: A mole of a perfect gas occupying a volume of 22.4L exerts an osmotic pressure of _______.
1 atmosphere
150
True or False: The size of the solute particles influences osmosis.
False
## Footnote
Osmosis is dependent only on the number of particles, not their size.
151
The degree of moisture or water vapor in gases, especially in the air
Humidity
152
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Actual mass of water vapor in a unit of volume of air at a given temperature, usually expressed in grams of water per liter
absolute humidity.
153
What does it mean if air is saturated with water?
Its relative humidity is 100%.
154
What is the relative humidity if air has a mass of vapor that is half of its saturation capacity?
50%.
155
How does temperature affect the air's ability to hold water vapor?
As air warms, its ability to hold water vapor increases; this capacity decreases as the air cools.
156
What is the saturation point of air at 20°C?
14.8g H2O/Kg air.
157
What is the saturation point of air at 15°C?
10.7g H2O/Kg air.
158
What is the general humidity range maintained in the operating room (OR)?
50-60%.
159
What may occur if humidity in the OR exceeds 60%?
Condensation on cool surfaces.
160
What could happen if humidity in the OR is less than 50%?
It may not suppress static electricity, which could be a source of ignition in OR fires.
161
which newton's law is this:
An object at rest or moving at constant velocity in a straight line will continue in that state until an external force acts upon it.
first law
162
Which Newton's Law states Force is equal to mass times acceleration (F = ma).?
his second law
163
What is the Third Law of Newton's Laws of Motion?
For every action, there is an equal and opposite reaction.
164
What principle do nerve stimulators, especially Mechanomyography, rely on?
Newton's First Law of Anesthesia.
165
What does Mechanomyography measure?
The force exerted by a muscle.
166
What is mass?
The amount of matter in an object.
167
What does mass represent in physics?
The resistance of an object to acceleration.
168
1 mole of liquid water occupies a volume of 18 ml at ___ atm and ___ degrees celsius
1 atm and 25 C
169
What percentage of volume do water molecules occupy in one mole of gaseous water?
About 0.07%.
170
What are Standard Conditions (STP) in chemistry?
0°C at 760mmHg (1atm).
171
What does Standard Ambient Temperature and Pressure (SATP) denote?
A reference temperature of 25°C and 760 mmHg (1atm).
172
What is pressure?
The force applied or distributed over a surface and expressed as force per unit.
173
What does Psi stand for?
Pounds per square inch
174
What does Psig stand for?
and what does that mean?????
Pounds per square inch gauge
the difference between the measured pressure and the surrounding atmospheric pressure
Example: At sea level your anesthesia gauge is set at 0 Psig, but the atmospheric pressure around the gauge is 14.7 Psi.
175
What is the atmospheric pressure at sea level in Psi?
What is the relationship b/t PSI and mmHg?
14.7 Psi or 1 atmosphere
14.7 Psi = 760 mmHg
176
How many cm H2O is equivalent to 1 mmHg?
1 mmHg = 1.3 cm H2O
177
What does Psia stand for?
Pounds per square inch absolute
178
What is the formula for pressure?
Pressure = Force / Area
179
how do you measure atmospheric pressure?
and define atmospheric pressure
barometer
The molecules of gases composing the atmosphere exert a pressure on all earthly surfaces. The molecules close to the surface of the earth are compressed by those above them.
One atmosphere of pressure (1 atm) = 760 mmHg (76 CmHg)
180
What is an ideal gas?
Name an ideal gas!
A gas assumed to exist under conditions in which there is no attraction between the molecules is referred to as an Ideal Gas.
There aren't any!!
181
What 3 principles must all real gases follow?
Volume of a gas is defined as a three-dimensional space in turn defined by container walls. It is assumed that the container has no leaks and the volume can be of varying sizes and units accordingly.
Temperature will have a lot to say about the underlying kinetics that the molecules processes.
Pressure is the consequence of gas molecules banging against the walls of the container as defined as force/area.
182
What is Boyle's Ideal Gas Law and give an example
At a constant temperature, a decrease in volume of a gas results in an increase in the pressure of the gas.
Squeezing the breathing bag on the anesthesia circuit à by decreasing the volume of gas in the bag there is an increase of pressure within the bag causing gas to flow from the breathing bag (an area of higher pressure) to the patient’s lungs (an area of lower pressure). A change in pressure is required for flow to occur. Traveling from areas of high concentrations of pressure to areas of low pressure concentrations.
Conversely, the release into the atmosphere of a large amount of gas from a compressed gas cylinder.
183
What is Charles' Ideal Gas Law?
Volume of gas at a constant pressure varies directly with absolute temperature.
A given quantity of gas, kept at constant pressure expands by 1/273 oK of its volume at 1oC for each degree rise in temperature.
example- a cuff pressure would increase an hour into a case b/c the air inside the cuff is heated from room to body temp
184
T/F Volume and pressure are directly proportional
False- inversely proportional
185
T/F- Volume and temperature are directly proportional
TRUE
Low temp= car tires need more air
Higher temp = makes the gas expand more
186
Math time:
what would the PSI of a tank be if it was 2200 psi at 0C then moved to a room that was 20C?
(20C x 1/273) x 2200psi = 0.073 x 2200 psi = 161.17 change in PSI
161.7 + 2200 = 2361.17psi
186
State Gay-Lussac's Ideal Gas Law
If the volume of a gas remains the same, as the temperature of a given volume of gas increases, the pressure of the gas also increases.
Each 1C change in temperature will yield a 1/273K increase or decrease in the pressure of the given gas. (starting for 0C)
Increase temp = increase of molecular motion of gas = increased pressure in container
187
Pneumonic for Ideal gas laws
Could These Guys Possibly Be Vigins?
B= PV
G=P/T
C= V/T
188
What does Avogadro’s Principle state?
Equal volumes of gases under the same conditions of temperature and pressure contain the same number of molecules.
189
How many molecules are in one mole of any substance?
6.023 x 10^23 molecules.
190
What is the significance of Avogadro's number in terms of physical objects?
An Avogadro's number of standard soft drink cans would cover the surface of the earth to a depth of over 200 miles.
191
What would happen if you had Avogadro's number of un-popped popcorn kernels?
The United States would be covered in popcorn to a depth of over 9 miles.
192
At what rate would it take to count the atoms in one mole if counting at 10 million per second?
About 2 billion years.
193
What does Avogadro’s Hypothesis state about the volume of a gas?
One mole of a gas at standard temperature (0°C) and standard pressure (1 atmosphere) occupies a volume of 22.4 liters.
194
What is Gram Molecular Weight?
Molecular weight of a compound expressed in grams, which equals one mole of a substance.
195
How does Gram Molecular Weight differ from Atomic Weight?
Atomic weight is the weight of each individual atom while gram molecular weight is expressed in grams (equalling 1 mole)
196
What is the molecular weight of Oxygen (O2)?
32 = one mole of 02
197
How many molecules are contained in one mole of O2?
6.023 x 10^23 molecules of O2.
198
Under standard conditions, what volume does one gram molecular weight (one mole) of O2 occupy?
22.4 liters.
199
What is the Gram Molecular Volume for gases at standard conditions?
22.4 liters per mole of the known gas.
200
What is the formula to calculate the Gram Molecular Volume ratio?
Molecular weight / Volume.
201
Fill in the blank: One mole of gas occupies ______ liters at standard conditions.
22.4 liters.
202
True or False: Avogadro's number is comprehensible in size.
False.
203
state the interrelationship b/t pressure, volume, temperature, and # of moles
it is a combo of what 3 gass laws?
combo of Boyle, CHarles, and avogadro's laws
PV=nRT
P is pressure
V is volume
n is the number of molecules (or moles)
R is the constant for all gases, approaching ideal behavior
T is temperature
204
Difference b/t gas and vapor
A gas is a matter which is usually present in our environment in a gaseous form.
A vapor is the gaseous state of a matter that mostly appears as a liquid in nature. (under environmental conditions) Vapor – gaseous aggregate of molecules
205
What are the vapor pressures of
Desflurane
Isoflurane
Sevoflurane
Des- 664 mmHg
Iso- 238 mmHg
Sevo- 160 mmHg
206
A vapor may be _______ by pressure w/o cooling while a gas cannot
liquified
207
What is required for all gases to be liquefied?
Compression under certain conditions
208
What must happen to molecular activity for a gas to liquefy?
It must be decreased by removing energy (cooling)
209
What is the critical temperature?
The temperature below which gases liquefy if sufficient pressure is applied
210
What is critical pressure?
The pressure necessary to cause liquefaction at the critical temperature
211
True or False: Pressure alone can cause a gas to liquefy.
False
212
Fill in the blank: A gas will not liquefy unless _______ is lost.
heat
213
What does Dalton's Law of Partial Pressures state?
The total pressure exerted by any mixture of gases is equal to the sum of all the partial pressures of the gases in the mixture
## Footnote
P = P1 + P2 + P3 + …….PN; each gas exerts pressure independently
214
What is the partial pressure of oxygen at sea level when isoflurane vapor is present?
1 atm = 760 mmHg, vapor pressure of isoflurane is 238 mmHg
## Footnote
Partial pressure of oxygen can be calculated using Dalton's Law
215
What is the definition of partial pressure?
The pressure exerted by one gas in a mixture of gases
## Footnote
Each gas in a mixture exerts its pressure independently
216
What condition is reached when the likelihood of a molecule moving from the liquid to vapor phase equals the likelihood of a molecule moving from vapor to liquid phase?
Equilibrium condition
## Footnote
This condition indicates that the system has reached saturated vapor pressure at a given temperature
217
What influences the vapor pressure of an anesthetic agent?
The physical properties of the individual agent and temperature
## Footnote
Vapor pressure is the force associated with the vapor phase
218
What happens to the liquid anesthetic when its vapor pressure equals atmospheric pressure?
All of the liquid converts to the vapor phase
## Footnote
This occurs at the liquid's boiling point
219
What is the boiling point of desflurane (Suprane)?
22.8 °C
why we keep it in a heater
## Footnote
This is the temperature at which desflurane transitions from liquid to vapor
220
What is the boiling point of isoflurane (Forane)?
48.5 °C
## Footnote
This indicates the temperature for isoflurane to boil
221
What is the boiling point of sevoflurane (Sevorane, Ultane)?
58.5 °C
## Footnote
The temperature at which sevoflurane changes from liquid to gas
222
Fill in the blank: At sea level, 1 atm is equal to _______.
760 mmHg
223
What is the percent saturation of isoflurane when the environment is fully saturated?
31%
## Footnote
Isoflurane saturation is calculated as (239/760)
224
What is the percent saturation of sevoflurane when the environment is fully saturated?
21%
## Footnote
Sevoflurane saturation is calculated as (160/760)
225
What is the percent saturation of desflurane when the environment is fully saturated?
88%
## Footnote
Desflurane saturation is calculated as (668/760)
226
What is the definition of saturated vapor pressure?
The point where the number of molecules returning to the liquid equals the number escaping the liquid.
227
What factors determine saturated vapor pressure?
Saturated vapor pressure is solely a function of the temperature of the system.
228
How does temperature affect molecular movement in a system?
The warmer the system, the more molecular movement and easier it is for molecules to escape.
229
What does MAC stand for in anesthetic terms?
Minimum Alveolar Concentration.
230
How are MAC values expressed in terms of mm Hg?
By multiplying the MAC value by 760 mm Hg.
231
What is diffusion?
The process by which molecules intermingle due to their kinetic energy of random motion.
232
What is a concentration gradient?
The difference between high concentration and low concentration.
233
True or False: Noticeable diffusion can occur without a concentration gradient.
False
234
What direction does diffusion occur?
From high concentration to low concentration.
235
What determines the direction of gas diffusion?
Differences in partial pressures.
236
Fill in the blank: A gas diffuses from a place where it is at high partial pressure to one where it is at ______.
lower partial pressure
237
What happens to gas molecules when they are liberated into a space?
They quickly become distributed throughout the space.
238
diffusion of a gas is directly proprotional to: (3)
partial pressure gradient of the gas
membrane area
solubility of the gas in the membrane
239
diffusion rate of a gas is inversley proportional to:
membrane thickness
Square root of the molecular weight
240
State Fick's Law of Diffusion
The rate of diffusion of a substance across unit area (such as a surface or membrane) is proportional to the concentration gradient.
The rate of diffusion of a substance across unit area (such as a surface or membrane) is proportional to the concentration gradient of each gas.
Concentration gradient
Remember that a concentration gradient develops when there are two different concentrations of the same molecules separated by a space or membrane
Gases always diffuse from one area of higher concentration or pressure to one of lower pressure.
The rate of diffusion is directly proportional to the concentration gradient.
The higher/larger the concentration gradient the faster the rate of diffusion.
This law only applies to a single homogeneous phase
Meaning that an ice cube will not diffuse in a glass of tap water.
241
What factors affect diffusion through a living membrane?
Factors include:
* Solubility of the gas in the constituents of the membrane
* The thickness of the membrane
* The permeability of the membrane
* The velocity of the membrane
242
What are the mechanisms of diffusion through a cell membrane?
Diffusion may take place by:
* Directly through the lipid bilayer of the cell membrane
* Through protein channels within a membrane
* By reversible binding to carrier proteins that can transverse the membrane
243
What does Graham's law of diffusion state?
The rate of diffusion of a gas is inversely proportional to the square root of either the density or the molar mass of the gas.
244
What happens to gas molecules overlying a liquid?
They can penetrate into the liquid and intermingle with its molecules. and can dissolve into the liquid
245
What is established when gas dissolves in a liquid?
Equilibrium is established between the dissolved gas and the undissolved portion.
246
What do the gas molecules within the liquid exert?
The same pressure as the gas molecules overlying the liquid.
247
What term is often used to refer to the pressure exerted by gas molecules?
Tension.
248
What does the solubility of gas in a liquid depend on?
The pressure of the gas overlying the liquid.
249
What is a "cornerstone of inhaled anesthetics"
It is the cornerstone of inhaled anesthetics.
The solubility of gas in a liquid depends upon the pressure of the gas overlying the liquid.
250
Fill in the blank: The solubility of a gas in a liquid is influenced by the _______ of the gas overlying the liquid.
[pressure]
251
what is henry's law
constants for oxygen and Carbon dioxide
The solubility of gas in a liquid depends upon the pressure of the gas overlying the liquid.
This allows for the calculation of the amount of O2 or CO2 dissolved in the blood.
Constants for the calculation of dissolved gases in the blood.
Oxygen = PaO2 x 0.003
Carbon dioxide = PaCO2 x 0.067
252
What does Henry’s law state regarding gas solubility?
With temperature remaining constant, solubility of a gas in a liquid is directly proportional to the partial pressure of the gas overlying the liquid.
253
What is the effect of administering another gas with N2O?
It is associated with a more rapid increase in alveolar concentration than would have been the case in the absence of N2O.
254
Why does N2O diffuse into the blood in greater quantities than N2 leaves the blood?
N2O is much more soluble in blood (34 times as soluble) than N2.
255
What is the second gas effect?
It is essentially a concentration effect associated with the simultaneous administration of two different anesthetic gases.
256
How does the solubility of nitrous oxide compare to potent inhalational agents?
Nitrous oxide exhibits relatively low solubility but is administered in very high concentration compared to potent inhalational agents.
257
What allows for significant alveolar to blood transfer of nitrous oxide despite its low solubility?
The large number of nitrous oxide molecules actually administered.
258
What happens to the concentration of volatile agents when nitrous oxide is administered?
There is a disproportionate reduction in the number of nitrous oxide molecules compared to potent, volatile anesthetic molecules, increasing the actual concentration of the volatile agent.
259
Fill in the blank: The solubility of N2O in blood is ______ times greater than that of N2.
34
260
What is the second gas effect?
A phenomenon where the presence of a second gas enhances the uptake of the primary anesthetic agent.
261
What is the main controversy regarding the second gas effect?
The difficulty in verifying the effect in vivo and the clinical insignificance of any verifiable effects.
262
What is a reverse second gas effect?
It refers to a situation where the presence of a second gas may inhibit the uptake of the primary anesthetic.
263
True or False: The second gas effect is widely accepted as clinically significant.
False
264
Fill in the blank: Generations of anesthesia providers have confused the nonspecific additive or synergistic effect for a specific _______.
second gas effect
265
What do Korman B. and Mapleson W.W. believe about anesthetics added to another?
They will likely augment the effect.
266
What did Poiseuille determine about laminar flow rate?
The laminar flow rate of an incompressible fluid along a pipe is proportional to the fourth power of the pipe's radius.
Small changes matter
## Footnote
This relationship highlights the significant impact of pipe radius on flow rate in laminar conditions.
267
How does turbulent flow resistance vary in relation to pipe radius?
Turbulent flow resistance varies inversely to the fifth power of the radius.
## Footnote
This is in contrast to laminar flow, where resistance is proportional to the fourth power of the radius.
268
Poiseuille's Law formula
Q= (pie)r to the 4th P / 8 n L
Q = Rate of Flow
P = the difference in Pressure
r = the radius of the tube
L = the length of the tube
n = the viscosity.
269
What is the opposition to fluid flow in any system called?
Resistance
## Footnote
Resistance is due to internal friction of fluid flow (cohesion) or friction against the walls of the system (adhesion).
270
How is resistance measured?
By the pressure difference between the inlet and exit points of the system.
271
What are the three factors that affect the pressure necessary to overcome resistance in fluid flow?
* Volume of flow
* Length of flow
* Diameter of tube
272
What happens to the flow rate when the diameter of a tube is halved?
The flow rate reduces to one-sixteenth of its original flow rate.
273
What happens to the flow rate when the diameter of a tube is doubled?
The flow increases by sixteen times the original flow rate.
274
What is viscosity?
A measure of a fluid's resistance to flow.
275
How does viscosity affect fluid flow?
Fluids with high viscosity do not flow readily, while those with low viscosity will flow more readily.
276
What effect does an increase in hgb/hct concentration have on blood viscosity?
It increases the viscosity of the blood.
277
What conditions increase viscosity?
* Low temperatures
* Patient age
* Cigarette smoking
278
What are ways to increase flow for IV fluid administration?
* Increasing the diameter of the needle (decreasing the gauge)
* Decreasing the length of the needle
* Increasing the diameter of the tubing
* Raising the IV bag to a greater height
* Decreasing the viscosity of the solution
279
How does polycythemia affect flow through tissues?
It decreases flow through tissues.
280
How does anemia affect flow through tissues?
It increases flow through tissues.
281
What is a method to reduce the viscosity of a unit of blood?
Adding NSS to PRBC’s.
282
What does Bernoulli's theorem describe?
The conversion of potential energy into kinetic energy at the point of constriction to overcome the resistance to flow.
283
Where is the pressure the lowest and the velocity the greatest in a tapered tube?
At the point of greatest constriction.
284
What must happen to satisfy the conservation of mass-flux in a fluid flowing through a constriction?
Changes in velocity and pressure occur.
285
What happens to the pressure in a constriction according to the conservation of energy?
The pressure reduces as the fluid gains kinetic energy.
286
What is the Venturi effect?
A special case of Bernoulli's principle involving fluid or airflow through a tube with a constriction.
287
What occurs to a fluid in a restriction due to the Bernoulli effect?
The fluid speeds up, reducing its pressure and producing a partial vacuum.
288
What is added to the point of maximum constriction in a Venturi system?
A 90o sidearm.
289
What is the purpose of the sidearm in a Venturi system?
To allow another fluid to be entrained and mixed with the original fluid.
290
Name one example of medical equipment that uses the Venturi principle.
* Atomizer
* Nebulizer
* Injector for oxygen therapy
291
What characterizes laminar flow?
Smooth, orderly flow of molecules moving parallel to the walls of the tube.
l;ow flow
292
What is the relationship between resistance and flow rate in laminar flow?
Resistance is directly proportional to the flow rate.
293
What primarily influences laminar flow resistance?
The viscosity of the gas.
294
Where is the flow fastest in a tube with laminar flow?
In the center of the tube.
295
How much faster can the central flow rate be compared to the mean in laminar flow?
As much as twice the mean.
296
What are turbulent flows associated with?
High velocities (high flows)
## Footnote
Turbulent flows occur when the velocity of the fluid is sufficiently high.
297
How do the lines of flow in turbulent flow compare to those in laminar flow?
They are no longer parallel
## Footnote
In laminar flow, the lines of flow are smooth and parallel.
298
What is the flow rate like across the diameter of the tube in turbulent flow?
The same
## Footnote
This indicates a uniform flow rate throughout the cross-section of the tube.
299
In turbulent flow, which factor becomes more important than viscosity?
Gas density
## Footnote
This shift in importance can affect the behavior of the flow.
300
What is the critical flow rate at which laminar flow becomes turbulent flow for anesthesia gas?
Approximately the numerical value as the diameter of the airway in millimeters
## Footnote
This rule of thumb helps predict when flow will transition to turbulence.
301
When does the flow of anesthetic gases in a 9mm internal diameter endotracheal tube connector become turbulent?
When the flow exceeds about 9 liters min -1
## Footnote
This is based on the critical flow rate rule of thumb.
302
What type of flow is usual in the bronchi and smaller air passages of the lungs?
Laminar flow
## Footnote
Despite being narrower than the trachea, these passages maintain slower air flow.
303
What type of flow occurs during quiet breathing in the respiratory tract?
Laminar flow
## Footnote
This indicates a smooth and orderly movement of air.
304
What is the critical flow rate for anesthesia gas in relation to airway diameter?
Approximately the numerical value as the diameter of the airway in millimeters
## Footnote
For example, in a 9mm internal diameter endotracheal tube connector, turbulent flow occurs when the flow exceeds about 9 liters min -1.
305
What type of flow predominates in the lower respiratory tract during quiet breathing?
Laminar flow
## Footnote
Turbulent flow tends to occur during speaking, coughing, or deep breathing.
306
What is the formula for Reynolds' Number?
Reynolds’ number = 2rvd/N
## Footnote
Where r is the radius, v is fluid velocity, d is fluid density, and N is fluid viscosity.
307
When does laminar flow convert to turbulent flow in a straight tube?
When the Reynolds number is greater than 1500-2000
## Footnote
This indicates a transition from laminar to turbulent flow.
308
What is the relationship of Reynolds' number to fluid properties?
Directly proportional to:
* Fluid Velocity
* Fluid Density
* Tube Diameter
Inversely proportional to:
* Fluid Viscosity
309
What happens at a branching point in terms of flow?
Turbulent flow will occur when the Reynolds number is 200-400
## Footnote
This can happen at curves, valves, or constrictions.
310
What is localized turbulent flow?
Occurs when gas flow is below the critical flow rate but encounters constrictions, curves, and valves.
311
How does the surface of anesthetic tubing affect flow?
The corrugated surface induces turbulence at a lower flow than a smooth tube.
312
At low flows, how is flow governed according to Poiseuille's Law?
By viscosity
## Footnote
The annular-shaped orifice around the float is relatively narrow.
313
At high flows, how is flow governed?
By density
## Footnote
The annular opening resembles more of an orifice.
