Test 3 đ§đťââď¸ Flashcards
(754 cards)
1
Q
How can we solve for the concentration of a gas in the lungs?
A
- Partial pressure of the gas
- Total pressure of all the gases (760)
FiO2= Partial pressure/ 760mmHg
2
Q
What percent of expired lung air is nitrogen?
A
75%
(569/760)
3
Q
What is the formula for nitrogen content in lung air?
A
PA(N2) / Total pressure
569/760
4
Q
Why is it more accurate to use 760 for total pressure?
A
Because that number accounts for water vapor taking up space
5
Q
What is the concentration of N2 in dry atmospheric air?
A
569/713=
79% (approx 80%)
6
Q
Why is the concentration of N2 in expired lung air lower than atmospheric N2?
A
Factor in water vapor when N2 is inhaled (gets diluted with water vapor in the lungs)
0.8 (760-47)= 569
569/760= 75%
7
Q
When would N2 absorbed by the patient be a concern?
A
We are normally not worried about it
Could be a concern with deep sea diving
8
Q
What gas is used in a lot of pulmonary function tests?
A
Pre-exisiting Nitrogen
9
Q
What is the purpose of the Fowlers Test?
A
Test to figure out how much anatomical dead space someone has by looking at expired N2
10
Q
If we hook a patient up to a test with nitrogen meter breathing normal room air at a normal rate and depth, what would expired N2 meter read?
A
75% or 569 mmHg on meter
11
Q
__________ have capnograph incorporated.
A
Ventilators
12
Q
When the capnograph is reading in mmHg, what device is being used to read this value?
A
EtCO2
13
Q
Capnograph can either be in ________ or _______ units depending on screen
A
mmHg (EtCO2)
% concentration
14
Q
What is needed to perform the Fowlers test?
A
- N2 meter
- Patient
- 100% O2 source
15
Q
How is the Fowlers test conducted?
A
- Patient starts breathing room air
- Then hook up to 100% O2
- Have them breathe up to 1L VT
- Expire
- First portion of breathe expired= anatomical dead space air 0% N2
- Transition phase when N2 starts to show up in expired air
16
Q
What parts of the expired breath are used to determine anatomical dead space during the fowler test?
A
*Amount of air expired up until midpoint of transitional phase
midpoint of transitional phase + Air expired without nitrogen= should be around 150cc
17
Q
What happens to N2 already in patient when they start to inspire from 100% O2?
A
Patients body will dilute out a little
*Any N2 coming out of the patient after breath of 100% O2 will be fro the air already in the lung
18
Q
What is the last portion of inspired breath?
A
Anatomical dead space
when breathing 100% O2 the anatomical dead space should have 0% N2
19
Q
How does inspiration pattern compare to expiration pattern?
A
Last air from inspiration is the first air out on expiration
20
Q
What is it called when the capnograph of the fowlers test expired N2 levels out?
A
Alveolar plateau (flat line)
21
Q
Who would be expected to have increased amount of anatomical dead space?
A
A tall person
22
Q
Why does increased amount of anatomical dead space matter?
A
More anatomical dead space would need to be a factor is the tidal volume for the patient
23
Q
How does increase anatomical dead space affect vent settings?
A
*Need 350cc air for gas exchangeâ more dead space means we need larger tidal volume
24
Q
Where is the transitional phase on the Fowlers Test?
A
25
What is the Nitrogen wash out test used for?
Used to analyze how EVEN the ventilation is in the lungs
26
What equipment is needed for the nitrogen washout test?
* N2 meter
* 100% O2 source
27
How is the N2 washout test conducted?
* Hook patient up to circuit and have them expire
* Patient then breathes normal VT and rate from 100% O2
* Each breath will dilute N2 that was already in the lungs
* Eventually there would be a very small amount of N2 coming from patient
28
What happens to expired N2 concentration during N2 washout test after the first breath of 100% O2?
N2 drops to 60% in the lungs
29
During the N2 washout test, when is the greatest reduction in N2 concentration?
Greatest reduction in N2 concentration is on the FIRST breath
(when there is the greatest amount of N2 in the lungs to be diluted)
30
What is the end point of the nitrogen washout test?
When patient is expiring N2 at a concentration of 2.5%
31
How long should it take for a healthy, 20y/o person to get down to 2.5% expired N2 for the N2 washout test?
Around 3.5 minutes
Way less than 7 minutes
32
How can we calculate how much the N2 is diluted on each breath?
* whats the starting volume
* how deep are the breaths
33
What is considered an abnormal result on the nitrogen washout test?
If it takes longer than 7 minutes to get down to 2.5%
Officially abnormal would be 2x longer than normal
34
N2 concentration graph shows decreases _________ when performing N2 washout test
Exponentiallyâ Low values at the bottom and the higher you go there is exponentially more N2 coming out of the patient
35
What does an abnormal N2 washout graph look like?
Curved shape, scattered data points compared to normal uniform/neat progression
Abnormalâ takes longer amount of time to wash out the N2
36
What is occurring in the lungs when N2 washout is taking longer than normal?
* Air is being directed to different places in the lungs on different breaths
* Inspired air being directed to many different placedâ washout of the N2 will not be even or orderly
(not even dilution with each breath d/t uneven ventilation)
37
What is the primary reason for abnormal N2 washout test?
Uneven ventilation
*sick lungs have a problem with even distribution of ventilation*
38
How would N2 washout test change in a patient with COPD?
Large lungsâ Larger volume of N2 in the lungs to start and with normal VT it would take longer amount of time breathing to wash N2 to concentration of 2.5%
39
What do flow volume loops primarily look at?
Air flow rates on very deep breaths
40
What is the deepest breath we could possibly take?
Vital capacity breath
41
What is vital capacity measuring?
Difference between TLC and RV
42
What is being shown on a flow volume loop on the top half vs the bottom half?
Top halfâ expired air
Bottom halfâ inspired air
43
What is the peak expiratory flow rate when expiring from TLC with maximum force?
10 L/s (can go higher in a healthy person)
44
What does the top curve show on a flow volume loop?
Shows the speed at which air is coming out of the patient
*different levels of effort*
45
When is air coming out the fastest on expiratory portion of a flow volume loop?
With a forced vital capacity (maximal effort)
46
What is effort dependence?
Time when the amount of effort we are applying dictates the expiratory flow rate
Large difference between how fast the air is coming out (flow rate) depending on patient strength and effort of expiration
47
What is effort independence?
Point where maximal expired flow rate is capped by something and doesnt allow us to expire air any faster
48
When does effort independence occur?
Lower lung volumesâ the amount of effort we are applying is not generating faster expired airflow rate
49
What shape on the flow volume loop do we get with inspiration?
Start with RV and inspire as fast as we can= oval shaped loop on bottom part of graph
50
At what point is peak rate of inspiration?
Half way pointâ when largest amount of effort is being applied
51
What happens to the rate of the vital capacity inspiration when less effort is given?
Rate of the inspiration is much lowerâ have to wait longer to get all of the air inspired
52
How does expiration flow volume loop shape compare to inspiratory flow volume loop shape?
Expiratoryâ Things are skewed to the left for fast flow rates then taper offf
Inspiratoryâ Oval shaped loop
(Upside down ice cream cone)
53
Typically the more unhealthy a pt is, the ________ air is expired
Slower
54
What does slow exhalation of air indicate?
Something wrong with the lungs
55
What is Peak expiratory flow rate the product of? (what forces help get air out of the lungs as fast as possible?)
Recoil pressure (PER) and Pleural pressure (PPl)
56
What is used in addition to the diaphragm to get air out of the lungs in a forced expiratory maneuver?
* Internal intercostal muscles
* Abdominal muscles
57
What is normal PER (PTP) in a healthy lung at total lung capacity?
+30 cmH2O
helps get air out of the lungs quickly
58
How does pleural pressure aid in maximal expiration?
Pleural pressure will be positive to get air out of the lungs as fast as possible
59
Where are internal intercostal muscles located?
Set of muscles in between the ribs inside the rib cage
60
What happens when internal intercostal muscles contract?
Pulls all the ribs closer together and decreases volume in the chest= increases pleural pressure
61
How does increase abdominal pressure create a more positive pleural pressure?
Pushes abdominal content up on the diaphragm
62
Combination of ________ and _________ constriction creates a positive pleural pressure during forced expiration.
* Abdominal muscles
* Internal intercostal muscle
63
If someone has COPD what are they dependent on to push air out of the lungs?
COPDâ terrible recoil pressure so they are entirely dependent on PUSHING air out of the lungs
64
What problems happen in patient with COPD when trying to get air out of the lungs?
At some point if you are pushing the air out the small airways will collapseâ limits the rate at which we can squeeze air out of the lungs
(problematic when there isnt enough elastic recoil)
65
What is a patient in the OR who is anesthetized and paralyzed dependent on to expire air? Why?
Entirely dependent on recoil pressure since the abdominal and intercostal muscles are paralyzed
66
If someone is on the vent and recoil pressure is low, what changes have to be made?
Have to allow more time for expiration
*Would need to decrease i-time so expiratory time would be longer*
67
Do PFTs look at inspiration or expiration?
Mostly looking at forced expiration (top half of flow volume loop)
68
What can peak expiratory flow rate get up to in a healthy person?
13 L/s
69
What happens to max expiratory flow rate with obstructive lung disease?
Max expiratory flow rate is less than normal (8 L/s)
Early on effort is useful to get some air out, then small airways collapse (changes shape on right side of graph)
70
71
What portion of the flow-volume loop do we usually look at for PFT?
Forced expiration âtop half of flow volume loop
72
What is the maximum peak flow rate in a healthy/young person?
13 L/s
73
What happens to max expiratory flow rate in obstructive lung disease?
Max expiratory flow rate is less than a healthy lung
*Elastic recoil is missing
73
Elastic recoil related to ________ ________ ________.
Small airway collapse
Early on the expiratory effort is useful to get air out, but at some point the small airways collapse and the shape of the graph changes
74
What is the max expiratory flow rate for a patient in COPD/obstructive lung disease?
8 L/s
75
What part of the graph is abnormal in a forced expiratory maneuver in a patient with COPD?
Effort independence phase is abnormal (tells about the behavior of the tissue on the forced expiratory maneuver)
76
What happens to the lung tissue in a person with restrictive lung disease?
More scare tissueâ More springs
*makes it more difficult to fill the lung up with air because of the extra tissue
77
What happens to max expiratory flow rate in restrictive lung disease? What causes this?
Max expiratory flow rate is reducedâ not from lack of recoil, but less amount of air we can pack into the lungs
*Lungs are less full*
78
What is the limiting factor that limits max expiratory flow rate in restrictive lung disease?
Unable to fill the lungs up with as much air
*an issue with lack of volume not elastic recoil issue
*Airway resistance is increased
79
What is FVC?
Forced vital capacity maneuver
*Always referring to expired portion of flow volume loop
80
On a flow function curve, what is indicated by the far right intersection of each expiration? (yellow highlight)
Residual volume (at the end of expiration)
81
What is a normal residual volume?
1.5L
82
What happens to RV with obstructive lung diseases?
RV is higher: 4.5L
83
Explain why RV is increased with obstructive lung diseases:
*Lungs are fuller at a higher pleural pressure
*Easier to fill up with air d/t less springs
*Much larger lungs affects the RV
84
What happens to RV with restrictive lung diseases?
RV is lower: 1L
*start with less air*
85
What is the volume difference from TLC to RV?
Vital Capacity
86
What is normal VC? How does vital capacity change with obstructive lung disease vs restrictive lung disease?
Normal: 4.5L
Obstructive: lower than normal 4L
Restrictive: lower then normal 3L
87
How does extra RV impact VC in obstructive lung diseases?
Extra RV means less working volume for air in and out of the lungs
Decreases VC
88
Smaller vital capacity and lower air flow indicated what?
Worse lung disease
89
If the x-axis on a PFT graph isnt labeled but there is a scale, what is assumed about the scale?
The scale length= 1L
90
Why do they not usually tell us RV from PFTs?
Know at the end of the loop that is RV
To get actual measurement would need to do indicator dilution test
91
What volumes/capacities can be looked at from expiratory flow function curves?
*Max expiratory flow rate
*Effort independence (right side)
*Vital capacity
92
What volume can we NOT see from expiratory flow function curves?
Residual volume
93
What can be assumed about the patient if they have a small vital capacity on the expiratory flow function curve?
Patients is sick/ has sick lungs
94
What happens to pleural pressure with forced expiration?
Pleural pressure is positiveâ can have different effects depending on the pressure in the alveolus and the airway
95
What is needed to get air out of the lung?
* Elastic recoil pressure (VERY important)
* Change in pleural pressure
96
What is the delta P is alveolar pressure is +35 cmH2O, Pleural pressure is +25cmH2O, and outside pressure is 0
Delta P= 35-0
+35 alveolar pressure pushes air out of the lungs fast
97
How does the force applied to push air out of the lungs affect the airway?
Pressure inside the airway decreases as we move up the respiratory tree from the alveolus
Force applied to get air out of the lungs can affect whether the small airway will stay open or not
98
Why is it uncommon for upper airways to collapse? (Conducting zones)
They have cartilage to prevent upper airway collapse during a forced expiration
99
Why are lower airways (closer tot he alveolus) more likely to collapse with a forced expiration?
They are made of soft tissue
100
Where is the vulnerable point in the small airway where it is most likely to collapse? When would this area most likely collapse?
Area just before the cartilage starts to show up (orange circle)
*would likely collapse is alveolar pressure is low but pleural pressure is high (internal pressure isnt high enough to keep open)
101
Whether or not the small airway stays open during a forced expiration is dependent on pressure in ____________ and ___________ pressure
Small airway
Pleural pressure
102
What would happen to the small airway if the pressure in the airway is +25 and the pleural pressure is +25?
The airway would NOT collapse
103
Why do we not worry about small airway collapse with passive expiration?
Pleural pressure is negative and the inner airway pressure is positive
104
When would the small airways collapse on forced exhalation? What type of lung disease would we see this in?
If airway pressure is less than pleural pressure
EX: someone with emphysema for 10 years (lose some elastic recoil)â alveolar pressure would be lower starting so would decrease below pleural pressure moving up the resp tree
105
Why do patients with emphysema have issues with air trapping?
Loss of recoil pressure= alveolar pressure is lowerâ small airway collapse when the pleural pressure is higher than the airway pressure
*problems with getting air out of the lung
106
What predisposes someone to small airway collapse?
*Narrow airwaysâ Low lung volumes, asthma
*Walls are closer together so it is easier to collapse that airway
107
Why can the upper airway pressure be lower than the pleural pressure without any issues?
Cartilage prevents upper airway collapse
108
What can cause someone to be more prone to collapse of upper airways?
Injuries where the cartilage is lost (not common)
109
Are the springs only in the alveoli to help hold them open?
No, springs are also in the small airways to help provide traction
110
What happens if we lose some of those springs helping with airways traction (obstructive diseases)?
The airway is more narrow and more susceptible to collapse
111
What happens if there are more springs in the small airways (restrictive diseases)?
Less likely for the airway to collapseâ thicker walls are harder to compress ie fibrosis
112
What are different airway obstructions that can occur?
*Fixed (intra or extra thoracic) Obstruction
*Variable Intrathoracic obstruction
*Variable intrathoracic obstruction
113
What is occurring with a fixed intra/extra thoracic obstruction?
Limits the rate we can push air out and get air in
*fixed because its a problem throughout the respiratory cycle*
114
What does a fixed airway obstruction do to the inspiratory and expiratory loops?
Cuts the top off both portions on the airway loop
115
What is an example used in class of a fixed intrathoracic obstruction?
ETT
*No matter how large the ETT the inner lumen has to be narrower than the trachea
*Creates higher resistance to airflow
116
Where is an extrathroacic obstruction?
Above the chest or outside the chest
117
Where is an intrathoracic obstruction?
Inside the chest
118
When does a variable intrathoracic obstruction occur during the respiratory cycle?
Not present throughout respiratory cycleâ usually only affects forced expiration
Problem during expiration because pleural pressure is positive
119
Why does a variable intrathoracic obstruction not cause issues with inspiration?
Normal inspiration pulls the obstruction out of the way
*chest pleural pressure is negative
120
How does a variable intrathoracic obstruction change the flow volume loop?
Cuts off the top of the flow volume loop â problems with expiration
121
What are 2 examples of variable intrathoracic obstructions?
Emphysema and Asthma
*Positive thorax affects soft tissue during expiration causing small airway collapse when recoil and traction is decreased
122
When and where do variable extrathoracic obstructions occur in the respiratory cycle?
Occur outside the chestâ trachea and upper airways
Affects inspiration
123
How does negative chest pressure (inspiration) create variable extrathoracic obstructions?
Making chest pressure negative is reflected in alveoli pressure and upper airway pressure
*Creates a weak point at the top of the airwaysâ negative internal airways pressure can cause the airways to collapse
124
What are 2 examples used in lecture that could cause variable extrathoracic obstructions?
* Missing cartilage (part of trachea removed)
* Paralyzed vocal cords (if cords are paralyzed and pressure in larynx is negative it can pull the cords shut)
125
What happens with variable extrathoracic obstructions with expiration?
Positive airway pressure will move obstruction out of the way
126
What does the flow volume loop look like when there is a variable extrathoracic obstruction?
Inspiratory part of the curve (bottom) will be flat
127
How can this variable extrathoracic obstruction be solved?
Put pt on vent it will make the problem go away with the positive pressure ventilation
128
What is FEV1?
Forced expiratory volume in 1 secondâ the amount of air you can get out of the lungs in 1 second
129
What is FVC?
Forced vital capacityâ usually give as a ratio of FEV1/FVC
130
Under healthy conditions we should be able to move ______% of our vital capacity out of the lungs during a 1 second period
80%
131
What is a normal FEV1?
80%
132
What does it mean it FEV1 is lower than 80%?
There is a problem
133
What do a lot of the FEV1/FVC graphs leave out?
RV
134
FVC is the same as ______.
Vital capacity
FVC= 4.5L normally
135
How long does it take a normal person with healthy lungs to get down to RV?
8 seconds (does not happen instantly even when totally healthy)
136
What distance is FEV1 measuring?
Start of expiration to end of 1 second
137
What is a common problem that will decrease FEV1/FVC ratio?
Airway obstruction
FEV1/FVC ratio would be less than 50%
138
What happens to FVC with airway obstruction compared to normal?
FVC is lower than normal
139
What happens to FEV1 when there is an airway obstruction?
At 1 second mark they havent been able to get as much air outâ air is coming out slower also takes longer to get to RV
140
What does an FEV1/FVC ratio of 50% indicate?
Abnormal, potential airway obstruction
141
What is this graph depicting?
FEV1/FVC in a healthy person
142
How would we know FEV1 is this graph plotted as a flow-volume loop?
There is no time axisâ we wouldnt know where the 1 second mark is on our own
143
What would you expect FEV1/FVC ratio to be in a person with restrictive lung disease?
Fairly normal ratioâ VC and FEV1 are both low so the ratio is normal ish
144
How can you tell the patient has restrictive lung disease if the FEV1 and FVC ratio is normal?
*FVC is low
*FEV1 is low
*Max expiratory rate on flow volume loop is <6L
145
If max expiratory flow rate is less than normal (>10L) what could that be hinting at?
Less volume to get rid of= restrictive lung disease
146
What is being shown by these graphs?
Restrictive lung disease
Low FVC, Low FEV1, Low max expiratory flow rate
147
What is a normal FEV1?
3.6L (80% of FVC)
148
How does FEV1/FVC look in a patient with COPD/advanced emphysema?
1 second mark 1.5L out but a lot more volume left in the lungs
FEV1/FVC would be low
149
How long does it take a patient with COPD to get to RV?
Takes a long time, have to cut axis to shorten it
150
What ventilatory change should be made for patients with obstructive lung diseases?
Need to give these pts longer expiratory time to allow the air to get out
151
What is a hallmark change on a flow-volume loop that indicates obstructive lung disease?
Peak and then flattens
152
What is usually the first PFT? Why?
Flow volume loopâ easy and cheap
153
If FEV1/FVR ratio is less than 70% there is a __________ problem
Obstructive
154
If FEV1/FVC is >70% are the lungs automatically classified as normal and healthy?
NO, could be normal or restrictive lung disease
155
How can we distinguish between normal lungs and restrictive lungs?
Look at FVC: Is it a normal volume or not
* Decreased FVC could be restrictive or obstructive
* Decreased or normal RV= restrictive
156
What happens to FVC, RV, TLC in obstructive lung diseases?
*FVC can be normal or decreased
*RV increases
*TLC can be normal or increases
157
If RV is increased what is likely the issue?
Obstructive lung disease
158
What doe DLCO (carbon monoxide diffusion test) measure?
Measures surface available for gas exchange in the lungs
159
What is the purpose of FEV1 reversibility with bronchodilator?
Tests if the condition can be reversed with bronchodilator
If it can be reversed: Reactive airway issue
If it cant: Something wrong with elastic tissues
160
If condition improved with bronchodilator what is likely the issue?
Asthma (reactive airway issue)
161
Which conditions would not improve with bronchodilator?
Emphysema (issue with elastic tissues of the lungs)
162
Which line shows normal FEV1/FVC ratio?
Red line:
Fev1= 4L
FVC= 5L
4/5= 80%
163
Which line shows restrictive lung disease (or a small person)?
Green line: smaller FVC
FEV1=3L
FVC= 3.5L
3.5/3= 85% (normal ratio)
164
Which line shows normal breathing? Which line shows maximal effort?
Z= normal breathing
W= max effort
X and Y: increasing effort from normal
165
What is the purpose of the closing volume/capacity test?
Shows details about smaller airways and their tendency to collapse
166
What is the closing volume/capacity test measuring?
Nitrogen coming out of the patient
167
How is the closing volume/capacity test performed?
*tell patient to go down to RV
*then inspire up to TLC from 100% O2 source
*N2 in the lung at TLC is the same N2 that was present at RV
*N2 in lung at RV is diluted by 100% O2 inspired
* then have pt expire to RV
*monitoring amount of N2 coming out of the patient at different times
168
What does FiO2 of 1 mean?
100% O2
169
What is a vital capacity maneuver?
Going from RV to TLC
170
What does the expired N2 concentration look like throughout the expiration during closing volume test?
N2 concentration coming out of the patient starts low and ends up high
*air coming out from different locations in the respiratory system
171
What does the concentration of the expired air during the closing volume test tell us about the patient?
* Air coming out of the patient is coming from different locations in the respiratory system
* Depending where the air is coming from we can tell properties of the lung
172
What is the condition of the lung at RV?
Base of lung is 20% full (room for 80%)
Apex of lung is 30% full (room for 70%)
*can fit more air in the bottom and less new air in at the top
173
How full are the alveoli at the apex and the base at TLC?
100% fullness
174
What is the partial pressure of N2 at the top of the lung and the base of the lung starting at RV?
569mmHg
should be consistent throughout the lung
175
What happens to N2 at the base of lung vs the apex of the lung when 100% O2 is inspired from RV?
*more O2 is added to the base of the lung â dilutes N2 more
*N2 partial pressure (concentration) at the base of the lung is more diluted than N2 partial pressure at the apical regions of the lung
*both apex and base will have lower N2 partial pressure
176
After 100% O2 inspiration to TLC from RV, how does N2 partial pressure differ from apex to base?
*Lower partial pressure of N2 at base
*Higher partial pressure of N2 at the apex compared to the base
*both apex and base N2 partial pressure is lower than RV
177
How many phases is the closing volume/capacity test split into?
4 phases
178
What is phase 1 of the closing volume/capacity test?
Expiring dead space air from the trachea and mainstems (conducting zones)
*No N2 in the first 100cc
179
What is phase 2 of the closing capacity/volume test?
Transitional period
*Anatomical dead space air mixed with alveolar air
*The further into phase 2 the more N2 expired
180
Which 2 PFTs have a transitional phase?
* Closing volume/Capacity test
* Fowlers test
181
What is phase 3 of the closing capacity test?
Plateau phase
* Mixture of air coming from all parts of the lung (everywhere)
182
Where is most of the air coming from at the beginning of phase 3 in the closing capacity test?
Base of the lung (top fills up first then the bottom fills up when inhaling from RV to TLC)
Expiration happens reverse of inspiration
183
Which portion of the lung is the last to fill up when inhaling from RV to TLC?
Base of the lung (more room to fill compared to the apex)
184
Expiration of air is ___________ from inhalation.
Opposite
185
First amount of air exhaled from alveoli that went up to TLC from RV is from _______ of the lung
Base
186
Why isnt phase 3 a flat line?
There is a mixture of air coming from different parts of the lung
*Initially should come from base then throughout phase 3 as we expire more air we see more air coming from the apex (high N2 concentration)
187
What is phase 4 of the closing volume/capacity test?
Abrupt change in N2 coming out of patient
188
What does the start of phase 4 tell us about the patients airway?
Tells where the small airways in the base of the lung are starting to collapse
189
How do we know that phase 4 air will only be coming from the apex of the lung?
Start of phase 4 is showing where the base of the lung alveoli are collapsing
Once the airways in the base are collapsed we wont get any more N2 from those alveoli
190
What is the point called where closing volume test changes from phase 3 to phase 4?
Closing volume/capacity
191
Closing capacity= closing volume + ____________
Residual voluem
192
What would it mean if the closing volume is earlier than normal?
Something is wrong with the small airways and they are collapsing earlier than normal
193
Why might small airways close earlier than normal? What does this do to phase 4?
* Not as much traction on them
* airways are thinner than normal
* airway is more narrow than normal
Phase 4 would start at earlier time point
194
What is the purpose of the closing volume/capacity test?
Super sensitive test to detect small changes in tissue behavior
195
What do you need to be able to conduct the closing capacity test?
*N2 meter
*O2 tank
196
Why might it be beneficial to include the closing capacity test in annual physicals?
Would tell people they have issues with respiratory system before it becomes a problem
197
What is one of the capacities/volumes that is subject to change with normal aging?
Closing capacity/volume
198
What lung volume increases with age?
Residual volume
199
How would phase 4 compare in a 20y/o compared to 70y/o who is completely healthy?
20y/o: phase 4 would be smaller and closing volume would be very small bc very little small airway collapse with forced expiration
70 y/o: airways start collapsing before we even expire down to FRC from loss of elastic tissue as a function of age
200
Why is closing capacity/volume higher with age?
Decrease elastic recoil and less traction on small airways predisposes to small airway collapse at larger lung volume
More elastic tissue loss= less elastic recoil of the alveoli= less traction on small airways= predisposes to small airways collapse at much earlier lung volume
201
Work of breathing is ________ in someone older compared to younger patients
Higher
202
After age _____ there will be small airway collapse on every breath
55
*Makes it more difficult to get fresh air in and it will require more work for them to breath on their own
203
The older we get the ______ airway collapse we have
more
204
The lungs are always bringing in _____ and getting rid of ______.
O2, CO2
205
What are the 2 forms of O2 in the blood?
1) Dissolved O2
2) Bound O2 (to Hb)
206
What is dissolved O2 measuring?
How much O2 has been forced into a solution
207
What happens to the O2 content in a beaker of water that has been sitting in the environment?
There will be some O2 that has been dissolved from the environment into the beaker of water
PO2 of environment (gas) can be used to push O2 into dissolved state in solution
Should have about the same PO2 in solution as environment because O2 is not very soluble
208
Why wont there be a large quantity of O2 dissolved in solution?
O2 is not very soluble
209
How does PO2 dissolved in solution act at the air water interface?
It pushes equally in the direction of the atmosphere
If a stray O2 escapes from solution then another O2 from environment would be pushed back into solution
210
How much O2 we have in a biological solution is dependent on its ___________
Solubility
211
What units is blood work measured in?
dL
212
What is the solubility coefficient of O2 in aqueous solution?
0.003 mLO2/mmHg
For each mmHg 0.003mL of O2 can be pushed into solution
213
How do we calculate how much gas we have (quantity= volume)?
Solubility x partial pressure of gas
0.003 mLO2/mmHg (100mmHg)= 0.3 mLO2/dL
214
How much O2 gas is in a normal arterial blood sample?
100mmHg (0.003mLO2/mmHg)= 0.3 mLO2 /dL of blood
215
What is normal O2 in pulmonary artery?
40mmHg under normal circumstances (same as systemic venous)
216
How much dissolved O2 is in a normal venous sample?
0.003 mLO2/mmHg (40mmHg) = 0.12 mLO2/dL
217
Why is the dissolved amount of O2 different between arterial and venous samples?
Pressure between arterial and venous samples decreases by 60mmHg â cuts down on dissolved gas in venous blood
218
What do we have to know to calculate how much dissolved O2 is in solution?
* PO2 of solution
* Solubility coefficient
219
How much O2/min do you need in the blood to stay alive?
250 mLO2/min
Dissolved O2 in the blood will not meet that metabolic demandâ not enough O2 solubility to pack the amount of O2 we need into each dL of blood
220
How does the body manage to get 250mLO2/min to circulate?
Hemoglobin (Hb) â helps the body with O2 transport
221
How much O2 can be carried/stored on hemoglobin?
1.34 mLO2/g of hemoglobin
222
What is the O2 carrying capacity of 1g of Hb?
1.34 mLO2/g of Hb
223
How much O2 is 15g of Hb capable of carrying?
15g (1.34 mLO2/g) = 20.1 mLO2 /dL of blood
224
How is the vast majority of O2 in the blood carried?
Carried by hemoglobin
225
How do we carry more than 20.1mLO2/dL on hemoglobin?
Must have more hemoglobin in the sample to carry more O2
226
When is hemoglobin sat at 100%?
When all hemoglobin in the sample is saturated with O2â every binding spot on Hb is occupied with O2
227
When would Hb sat=100% if Hb is normal (15g/dL)?
20.1mLO2 in the sample
228
How much O2 would be bound to hemoglobin in a sample if the Hb sat is 10%?
20.1 (.1)= 2.01 mLO2 bound if Hb is 15g/dL
229
What 2 factors do we need to know to figure out how much O2 is on hemoglobin?
* Hemoglobin saturation number
* Carrying capacity
230
What is a normal hemoglobin in healthy adults for our class?
15 g/dL
231
Do men usually have higher or lower hemoglobin levels?
Men have more Hb than average
Women have less Hb than average
232
What variables are used to express adult hemoglobin?
A Hb
HbA
233
What is the structure of adult hemoglobin?
Tetramer with 4 component parts
- 2 alpha subunits
- 2 beta subunits
234
How many molecules can adult Hb carry?
4 O2 molecules
235
What is the structure of fetal hemoglobin?
Tetramer
- 2 alpha subunits
- 2 gamma subunits
236
How does fetal hemoglobin O2 affinity compare to HbA?
Fetal Hb has a higher affinity for O2
237
Why is it necessary for fetal Hb to have a higher affinity for O2 that adult Hb?
Fetus can get O2 from the moms blood because Hb in fetal circulation has higher affinity for O2 than maternal Hb
If fetal Hb didnt have higher affinity then O2 wouldnt want to unload into fetal circulation
238
When does fetal Hb become adult Hb?
Fetal Hb goes away when we are born and is replaced with adult Hb fairly fast
239
What is erythropoietin?
Growth hormone released if the kidney if hypoxicâ if deep parts of the kidney are hypoxic EPO is released and more RBCs are formed
240
What is the function of erythropoietin?
Significant contributor that governs how much Hb we have floating around
Epoâ more RBCsâ adds to hemoglobin in circulation
241
What is necessary to supplement in patient with bad kidneys to maintain adequate hemoglobin levels?
Synthetic erythropoietin
242
What is myoglobin? What is the function?
Structurally similar to Hbâ higher affinity for O2 compared to adult Hb
Functions to help O2 unload into red muscles that need the O2 (lots of iron in the form myoglobin)
243
Which body parts have high myoglobin amount?
Red skeletal muscleâ iron in the form of myoglobin, we want O2 going into working red skeletal muscles makes sense myoglobin has higher affinity for O2
244
What element is in all hemoglobin?
Ironâ reversibly binding O2
245
What part of hemoglobin reversibly binds O2?
Iron
246
Why is it said eating red meat might be unhealthy? (Not a shared opinion by Schmidt)
D/t the iron found in myoglobin
247
What is the O2 content measuring?
Dissolved O2+ Bound O2
248
Under normal conditions (PaO2 100, Hb 15 and 100% saturated) what is the O2 content in an arterial sample?
0.3 + 20.1= 20.4 mL
249
Why is most of O2 in a sample bound to Hb?
O2 is not very soluble so its happier to be bound to Hb than dissolved
250
What happens if half of Hb binding sites become occupied with carbon monoxide?
Less room to carry O2â only 1/2 of the original binding sites to carry O2
O2 bound to Hb would be half normal= 10 mLO2/dL
251
What is the condition when we dont have a normal amount of blood?
Anemia
252
What happens to O2 carrying capacity with anemia?
O2 carrying capacity will be lower even if available O2 binding sites are 100% occupied
Lower carrying capacities= less O2 in solution
253
How does anemia affect the oxyhemoglobin dissociation curve?
Shift to the right
- decreases Hb affinity for O2
254
How does CO affect hemoglobin?
- Carbon dioxide displaces O2 and binds tightly to Hb (difficult for it to fall off on its own)
- CO cuts down carrying capacity for O2 and increases Hb affinity for O2 in a bad way
255
How does carbon monoxide change the dissociation curve?
Slight leftward shift= increased affinity for O2
O2 not wanting to unload when CO is bound
256
What is the treatment for carbon monoxide poisoning?
100% O2 after exposureâ enough O2 in solution from time to time the CO that falls off will be replaces with the O2
257
What does a left shift of deoxyhemoglobin dissociation curve indicate?
Increased affinity for O2, less prone for O2 to fall of Hb
258
What does a right shift of deoxyhemoglobin dissociation curve indicate?
Decreased affinity for O2, more prone for O2 to fall off Hb (can be used by the tissues)
259
What does bound O2 measure?
Oxygen saturation
260
What is the ideal % O2 arterial saturation in a healthy person?
A little less than 100%â actual number is 97.4%
Less than 100% would be a little less than 20.4 mLO2/dL (O2 content)
261
What is the O2 content in a venous sample?
15 mLO2/dL
262
How does venous Hb sat compare to arterial Hb sat?
Venous Hb is 3/4 saturated
1/4 O2 that was on Hb has fallen off and 3/4 remains
75% O2 sat in venous blood
263
What is the O2 content in a venous sample?
[(20.1) x .75] + [0.003 x 40] = 15.195 mLO2/dL
264
What circulatory bed is an exception to O2 sat of 100% in arteries and 75% in veins?
97% of all circulation beds follow this pattern
Heart and coronary arteries do notâ arterial sat 100% going into coronary circulationâ Hb sat in coronary sinus is 25% (much lower than other circulatory beds)
265
The heart is set up to extract ___% of O2 funneled through the coronaries
75%
The heart is efficient at pulling O2 out and using it in a way that drops Hb sat to 25%
Decreases amount of coronary perfusion we need
266
What is a negative aspect of how the heart utilizes O2/ the difference in O2 sat between arterial and venous sat?
Little room for errorâ Less O2 left in the veins to pull from if there is a problem
If a clot is affecting blood flow in the heart there isnt a lot of O2 in other areas for the injured area to pull from
267
Why do peripheral circulatory have an easier time creating collateral flow in contrast to the heart/coronary arteries?
Peripheral circulatory bed has more O2 left in the veins to pull from if there is a problem
268
How does fetal hemoglobin affect the deoxyhemoglobin dissociation curve?
Fetal Hb has a higher affinity for O2â shifts curve to the left
269
How the adult Hb shifted on a deoxyhemoglobin dissociation curve compared to fetal Hb?
Adult Hb has lower affinity for O2 than fetal Hbâ adult Hb curve is shifted to the right of fetal Hb
270
What happens to adult Hb saturation is PO2 in a solution is increased?
Increases oxyhemoglobin saturation
Increase gas in solutionâ Higher PO2 â Packs more O2 onto hemoglobin in solution
271
How much O2 pressure is needed to saturate adult Hb to 50%? What about fetal Hb to 50%?
Adult Hb: over 26.5 mmHg
Fetal Hb: 18mmHg
Fetal Hb requires less gas pressure to populate 50% of Hb binding sites d/t its higher affinity for O2
272
What is a consequence of fetal Hb high affinity for O2?
It doesnt like to let go of bound Hbâ solution has lower PO2
273
What is another way to think of the gas pressure of O2 in regards to hemoglobin?
How willing is Hb to drop off O2 or how reluctant will O2 be to getting pushed onto O2 sites (what pressure is needed to saturate a certain amount of Hb)
High PO2= really willing to drop off O2
Low PO2= wants to hang onto O2
274
What happens to PO2 the more dissolved gas there is?
Higher PO2
275
If Hb doesnt have a high affinity how do we get adult Hb saturated to 100%?
Increase PO2
276
When is fetal Hb 100% saturated? When is adult Hb 100% saturated?
Fetal: PO2= 30mmHg
Adult: PO2= 100mmHg
277
How is total oxygen calculated?
Dissolved O2 + Bound O2
278
How is most of the O2 found in solution?
Bound to Hb (O2 doesnt like to be dissolved)
279
What makes venous blood more acidic than arterial blood?
More CO2 and protons in venous blood
280
Why is venous sat usually lower than 75%?
Venous blood is more acidic and that reduces Hb affinity for O2
281
Where in the heart is the hemoglobin sat 25%?
Coronary sinus (venous blood vessel in the heart)
282
What is the total O2 content in the veins?
15.195 mLO2/dL (dissolved and bound)
(20.1 x 97.4) + 0.12
283
What is the total O2 content in arteries?
technically 19.88 mLO2/dL (dissolved and bound)
(20.1 x .974) + 0.3
284
What is the difference in O2 content between veins and arteries normally?
5mLO2/dL of blood
285
What is another term for volumes %?
O2 Content if hemoglobin is normal
286
What should hemoglobin sat be with arterial blood sample PO2= 100mmHg?
100%
287
With a normal hemoglobin level what should O2 content be in arterial blood?
20 mLO2/dL
288
What is the hemoglobin sat for a sample of venous blood with PO2 of 40mmHg?
Should be around 75%
289
What is the O2 content in a venous sample if hemoglobin is normal?
15 mLO2/dL
290
What is PCO2 of arterial blood?
PaCO2= 40mmHg
291
What happens to O2 if there is an increase in PCO2?
O2 will want to unload and become available for the tissues to use
shift of curve to right
292
How does O2 become available for the tissues to use?
Only O2 available to tissues is the dissolved form of O2
Tissues cant pull O2 of Hb it needs to fall off
293
Most tissues are unable to pull O2 off Hb, what is an exception to this?
Myoglobin (red muscle) can pull O2 off Hb
294
What happens to O2 is PCO2 decreases?
Decrease metabolic activity= causes left shift in curve and O2 would not fall off
295
What is the Bohr effect?
Tern used to talk about O2 unloading in the tissuesâ As we enter more hypercapnic/acidic/ metabolically active environment O2 curve shifts to the right
Facilitates O2 loading
296
How does an alkalotic environment affect Hb affinity?
Increased pH= decreased CO2= increased Hb affinity for O2= curve shift to left
297
How does an acidotic environment affect Hb affinity?
decrease pH= increase CO2= more O2 unloading= decrease Hb affinity for O2= shift curve to right
298
How does lung air PCO2 compare with pulmonary arterial PCO2 before equilibration? How does this affect oxyhemoglobin curve?
PACO2= 0mmHg
PaCO2= 45mmHg
Moves curve to the left and facilitates O2 loading
299
What is 2,3 BPG/ 2,3 DPG?
Byproduct of metabolism throughout the bodyâ important controller of O2 unloading and helps control metabolic needs of the tissue
Increased metabolism= increase amounts of 2,3 BPG
300
How does 2,3 BPG affect oxyhgb dissociation curve?
More 2,3 BPG: shift curve to right (release more O2)
Less 2,3 BPG: shift curve to the left (O2 delivery is difficult)
301
What is the full name of 2,3 BPG/ 2,3 DPG?
- 2,3 Bisphosphoglycerate
- 2,3 Diphosphoglycerate
OR
Bisphosphoglyceric acid
302
Is a compound ends in -ate it is likely a _________.
Acid
303
How does temperature affect oxyhemoglobin curve?
Warm temp: Shift to right (O2 falls off easier)
Cold temp: Shift to left (O2 hangs on longer)
this is true for all tissues in the body except the lungs
304
How does temperature in the lungs affect O2 loading and unloading from Hb?
Temp in the lungs is 37C but compared to temp in metabolically active tissue which is higher than 37C
O2 in the lungs helps with O2 loading in lungs (since temp is lower than other tissues)
305
What is O2 loading and unloading in the lungs dependent on?
Curve shift effect
306
How does a high fever affect O2 loading and unloading in the body?
Increases lung temp so makes it more difficult to grab O2 out of the lungs
shift curve to right
307
How does myoglobin affinity for O2 compare to adult Hb?
Myoglobin has higher affinity for O2 than HbA
308
Which sample has a lower pH: venous or arterial?
PaCO2= 40mmHg
PvCO2= 45mmHg
venous blood has lower pH d/t more CO2 picked up
309
How does venous oxyhemoglobin curve compared to arterial curve?
Normal venous curve is shifted to the right (more CO2 and lower pH) compared to arterial
310
What is PO2 in normal venous blood?
PO2= 40mmHg
311
What is typical hemoglobin sat in venous blood when PO2 is 40mmHg?
as low as 60% (60% Hb bound by O2)â close to healthy venous Hb sat of 70%
312
What would be expected of venous Hb sat in a patient who is super sick/acidotic in the ICU?
Venous Hb will be lower
- More acidotic= less saturated Hb because O2 wants to fall off
- Bad heart drops venous Hb sat
Explanation for lower SvO2 observed clinically
313
What is the short hand for venous O2 saturation?
SvO2
314
What are some conditions that cause SvO2 to be high?
If tissue isnt extracting a lot of O2 d/t low metabolic demandâ brings venous Hb sat up
315
What is a P50 value?
Partial pressure of O2 required to bring Hb oxygen saturation up to a level of 50%
PO2 of the solution that is able to saturate Hb with O2 to 50%
316
What is a normal P50 value for O2 when Hb is normal?
26.5 mmHg
317
What happens to P50 value is something shifts oxyhemoglobin curve to the right?
P50 value goes up
Hb is less prone to grab O2 in solutionâ would need more O2 to bind half of the Hb site with O2 and more partial pressure
318
What happens to P50 value is something shifts oxyhemoglobin curve to the left?
P50 value goes down
Hb has high affinity for O2â takes less partial pressure of O2 to bind half Hb O2 sites
319
What causes P50 values to shift?
They can shift as Hb affinity for O2 changes
320
What 3 form can CO2 have in arterial blood?
1) Dissolved
2) Carbamino bound
3) Bicarb state
321
What percent of CO2 in our body is dissolved?
Small portion of total CO2 in out system is dissolved (5%)
322
How is dissolved CO2 calculated?
Solubility of CO2 x ppCO2 in solution
323
What is the solubility of CO2?
0.06 mLCO2/mmHg/dL
324
How much dissolved CO2 is in normal arterial blood?
(0.06 mLCO2/mmHg/dL) (40mmHg)= 2.4mLCO2/dL
325
How much dissolved CO2 is in normal venous blood?
(0.06mLCO2/mmHg/dL) (45mmHg)= 2.7mLCO2/dL
326
How do we calculate partial pressure of a gas in solution if we are only given the pressure in the environment?
Partial pressure of gas in solution should be same as what is in the environment surrounding the solution
327
How does CO2 combine with carbamino groups?
If there is a lot of CO2 in an area an H+ can fall off and is replaced with carbamino compound
To have this binding there must be an accessible terminal amine group for CO2 to attach to
328
What proteins buffer H+ in the blood?
- Hemoglobin
- Immunoglobulins
- Clotting factors
329
What would cause increased amount of carbamino compounds?
More CO2 in solution= more carbamino compounds
330
What percent of total CO2 in the blood is on carbamino compounds?
5%= 2.4mL CO2 in normal dL of arterial blood
331
What percent of CO2 in circulation is floating around as HCO3-?
90%
332
What are the steps of CO2 turning into HCO3-?
CO2 combines with water to from H2CO3â Carbonic acid is not stable and falls apart into bicarb and H+ or CO2 and H2O
333
How does carbonic acid decide which parts to disassociate into?
The reaction moves depending on the environment
334
What happens in the reaction if blood has a highly acidic environment with lots of CO2?
CO2 combines with water to form carbonic acid which then disassociated into H+ and HCO3-
335
What happens to the reaction if there isnt much CO2 in the environement?
Low CO2 in environment would encourage reaction to go in opposite direction
Low CO2 causes excess protons to react with bicarb to from H2CO3 which then breaks into more CO2 and H2O
336
What enzyme is responsible for speeding up the breakdown/ put together of carbonic acid?
Carbonic anhydrase: pulls water out of carbonic acid (anhydrous)
337
What is the chemical reaction with carbonic acid dependent on?
How many products vs substrates there are in the area
338
How much CO2 is in the form of bicarb in an arterial sample?
43.2 mLCO2/dL of blood is in the form of bicarb
339
How is total CO2 content in an arterial sample calculated? How does this number compare to arterial O2 content?
2.4x20= 48mLCO2/dL
Higher than O2 because CO2 is more soluble
340
Why is CO2 in the form of bicarb lower in a venous sample?
More protons in venous blood that consume some of the bicarb
341
What does CO2 content measure?
Dissolved CO2 + Carbamino compounds + Circulating HCO3-
342
Arterial blood should have a oxyhemoglobin saturation of _____
97.5%
343
What is a normal CO2 content in arterial sample?
48mLCO2/dL
Arterial blood is oxygenated (O2 takes up room) so there is less room for CO2
344
How does venous CO2 content compare to arterial CO2 content?
Venous blood has low oxyhemoglobin sat (70%) so there is more room for CO2 in deoxygenated blood
345
What is CO2 content in venous sample?
52.5mLCO2/dL
346
How does an increase in oxyhemoglobin lead to less CO2 transported?
Hemoglobin can be the protein to bind to terminal amine groups
more oxyhb= less exposed terminal amine groups=less carbamino compounds
"R" protein can be hemoglobin
347
How does more DEOXYhemoglobin affect CO2?
Hb can bind to CO2 molecule of it can buffer protons
If HB buffers protons that can push reaction further to fit more CO2 in the blood
348
What makes it much easier for blood to carry CO2 in all of its forms?
O2 falling off Hb
349
What are the 3 main things Hb can do?
- Bind or release O2
- Form carbamino compounds
- Buffer protons
350
What is the difference between arterial and venous CO2 curves?
Amount of CO2 being dropped at the lungs (Hemoglobin oxygenation)
351
How much CO2 is unloaded per dL of blood that passes through the lungs?
4.5 mLCO2 unloaded
352
How much O2 is unloaded from artery to veins?
5mLO2/dL
353
As the blood unloads _____mL CO2, _____mL O2 are coming on board
4.5mL CO2
5mLO2
354
Why do we have to look at both arterial and venous CO2 curves to get correct CO2 content?
Just looking at arterial would give a lower number since it has a lower capacity to carry CO2
355
What is Haldane effect?
- Deoxygenated blood has more room to transport CO2
- amount of CO2 transport we can have is dependent on oxyhemoglobin saturation levels
356
How do we calculate oxyhemoglobin saturation level on a CO2 dissociation curve?
Difference between arterial sample and venous sample
357
How is CO2 transported at peripheral circulatory beds?
Tissues produce CO2 as byproduct of metabolismâ CO2 can enter CV through capillary wall since its a gas
Some CO2 dissolves in plasma
Larger portion CO2 goes into RBC (a portion stays dissolved) but larger portion combines with water to form carbonic acid
Carbonic anhydrase inside RBC to speed that reaction up
Large portion of HCO3- leaves RBC and enters plasma via bicarb/chloride exchanger on RBC
Proton from formation of HCO3- can hang in solution and is buffered by proteins
O2 levels in tissue are decreasing facilitates O2 unloading into plasma then into tissues
Other portion of CO2 combines with carbamino compound
358
What is the primary protein buffer of protons in the RBC?
Hemoglobin
359
Which form of hemoglobin is the best H+ buffer?
Deoxyhemoglobinâ once O2 unloads from oxyhemoglobin then it can better accept protons because there is more room
360
Deoxyhemoglobin is a _________ acid
Weaker acid than oxyhemoglobin
361
_________ acids are more prone to accepting a proton
Weaker
362
Do strong acids want to accept protons?
No, They want to donate protons
Oxyhemoglobin is a stronger acid than deoxyhemoglobin
363
What helps O2 unload at the tissues in the periphery?
- pH in RBC
- Bringing on CO2 creates a more acidic environment in RBC
- More protons around decreases Hb affinity for O2 and helps with unloading of O2 at tissue
364
Where are carbamino compounds found?
Within hemoglobin or any of the other proteins in the blood cell or in the plasma
365
How does gas transport happen in the lungs?
CO2 is unloaded into lung air from blood (gradient from pulmonary art= 45mmHg to lung air PCO2= 40mmHg)
CO2 is moved into alveolus some of CO2 in plasma shifts over: large portion from RBC, portion dissolved in blood
Getting rid of CO2= some protons that were buffered by deoxyhemoglobin can fall off
Protons combine with bicarb in RBC to form carbonic acid and makes more room for bicarb
Bicarb is brought in from periphery and Cl- is moved out of RBC
Getting rid of CO2 and H+ allows for more deoxyhemoglobin= higher affinity for O2
Bring on O2 and getting rid of H+ and CO2
366
How is bicarb transported in and out of a RBC?
Bicarb/Chloride Exchanger on RBC
367
How long does it take for gas exchange to happen in pulmonary capillaries of a healthy young adult?
0.25 seconds
368
What happens to PO2 as deoxygenated blood is moving through pulmonary capillaries?
- Blood moving through capillaries should have PO2=40mmHg
- Hit plateau when PO2 close to 100mmHg
- O2 comes in an dissolved in blood and is then packed into storage location on Hb
- Takes about 0.25 seconds
369
What happens to gas exchange is PO2 of blood in pulmonary capillaries is lower?
Gas exchange might take longer because more O2 would need to be picked up
370
What can cause a drop in PO2 in blood entering pulmonary capillaries?
Heavy exertion
371
How long does blood hang out in a healthy alveolus at rest?
0.75 seconds total in pulmonary capillaries
372
What happens to time blood spend in the pulmonary capillaries when cardiac output is increased?
More recruitment and distention= faster movement of blood through pulmonary capillaries
373
Cardiac output can pick up to the point where blood only spends _____ seconds in pulmonary capillaries
0.25 seconds (fine for this to happen in a healthy person)
374
When might a diffusion problem be noticed?
With increased exertionâ causes issues when the lungs are in bas shape/ impaired gas exchange with increase CO (need longer time for adequate gas exchange)
EX: fluid in the lungs
375
How long does it take blood coming into the pulm capillaries to equilibrate with N2O?
Will equilibrate with N2O in <0.25 seconds
nitrous is fairly insoluble so not many places to go in the blood
376
What is a gas discussed in lecture that is less soluble than O2?
N2O
377
What is the reason for fast onset and fast offset with nitrous?
Low permeability in the blood
378
N2O is very soluble when comparing to ____, but it is not more soluble than O2
N2
379
How does carbon monoxide absorb into the lungs?
Steady absorption and doesnt come into equilibrium with lung air
Used as diagnostic test to look at diffusion capability of the lungs
380
What does slow diffusion of CO in the lungs mean vs faster diffusion of CO in the lungs?
Slower diffusion of CO= lung problem
Faster diffusion of CO= better diffusion
381
What is CO used for as a diagnostic for?
Used to test diffusion capacity of the lungs
382
When giving low concentrations of CO, what other gas does CO diffusion closely mimic?
Similar to diffusion of O2
383
How is oxygen structure different from carbon monoxide?
O2: 2 oxygen atoms
CO: 1 oxygen atom, 1 carbon
384
What can the blood test for carboxyhemoglobin be indicative of?
Indicative for smoking or some other CO exposure
385
Blood spend _____x as long than what is necessary for gas exchange
3x
Functions as a safety net: even if someone has pneumonia it shouldnt affect too much because the blood hangs out longer that it has to in the pulmonary capillaries
386
When diffusion capacity is 1/4 normal, how does that affect time for gas exchange in the lungs?
takes 0.75 seconds for O2 level to reach alveolar gas
387
When diffusion capacity is 1/8 of normal what would PO2 be?
PO2 would only be around 60mmHg
Diffusion limited O2 exchange
388
When is diffusion limited O2 exchange usually an issue?
When fluid is in the lungsâ O2 doesnt like to be in water
Too much water between the alveolar air and the underlying pulmonary capillaries makes gas diffusion very difficult
389
Why does it not really matter that CO2 can move faster than O2?
CO2 unloading and O2 loading are connected and dependent on each other
390
What causes perfusion limited gas exchange in the lungs?
- Gas that has equilibrium between blood in the capillary and alveolar air
- Happens with PO2: blood leaving pulmonary capillary should have roughly the same PO2 as alveolar air
391
If perfusion limited gas exchange a normal occurance?
Happens under normal circumstances with O2
O2 diffusion is a perfusion limited compound
Amount of O2 absorbing is entirely dependent by how much blood is moving through the lungs
392
What is the only way to absorb more O2?
Pump more blood through the lungs
393
How will perfusion limited gas exchange look when graphed?
- plateau phase
- happens with N2O and O2
394
What occurs with diffusion limited gas exchange?
- No equilibration between pulmonary capillary blood and alveolar air
- limited by the fact that rate of diffusion is low
- no plateau phase
- happens with CO
395
What variables are involved in Ficks law?
(Surface area) x (Diffusivity) x (Pressure difference) / (Thickness)
396
How does a thicker barrier impact gas exchange?
Lower gas exchange
397
How does surface area impact gas exchange?
More surface area available= more gas diffusion
398
How does perfusion affect surface area and gas diffusion?
More perfusion= more blood vessels and alveoli involved= greater surface area= more gas diffusion
399
How does exercising impact gas exchange?
Increases recruitment which activates alveoli and increases area for gas exchange
400
What happens to gas exchange when there is low perfusion to the lungs?
Low recruitment and less surface area for gas exchange
401
How does a smaller pressure difference impact gas exchange?
Slows rate of diffusion
402
What does diffusivity take into account?
- Solubility of the gas
- Square root of molecular weight of the gas
403
CO2 is _____X more soluble in blood than O2
24X
404
On the basis of size, we expect O2 to move faster than CO2 because CO2 is larger, but why does CO2 have a higher diffusivity?
CO2 is more soluble so that beats the size difference for higher diffusivity
405
CO2 diffusivity is ____x faster than O2
20X
406
What is a normal V/Q ratio?
0.8 for normal V/Q ratio
Alveolar minute ventilation (4200 mL of air) / CO (5000mL of blood)
407
What is this an example of?
A shunt (ventilation problem)
408
How does ventilation issue impact V/Q ratio?
Decreases top number: V/Q would be lower than normal
409
How would blood gas look from an alveolus with a shunt?
Blood entering the capillary would be similar to blood leaving the capillary
410
What is happening in this picture?
Perfusion problem creating alveolar dead space
411
How would alveolar gas change in a alveoli this is being ventilated but not perfused?
Alveolar air would be close to inspired air: PAO2=150 PACO2=0
412
How does perfusion issue in the lugs affect V/Q ratio?
Decreases bottom number and makes V/Q higher than normal
413
What is the upper limit to V/Q ratio for perfusion issue?
Infinity
414
What can the v/q ratio get to with ventilation problem?
Can get to 0
415
What is a shunt?
Blood flow through a non-ventilated alveolus
416
How is alveolar dead space created?
Ventilating alveolus with no blood flow
417
Is V/Q ratio that same throughout the lung?
No, different parts of the lung have different V/Q ratios
Not always extremes sometimes just minor differences
418
What would happen to O2 content in an area with lots of perfusion but less ventilation?
Lower O2 content than average
419
How do we get normal V/Q ratio of 0.8?
All regions of the lung V/Q average to normal numbers
420
How does ventilation and perfusion at the top of the lung differ from the base of the lung?
Lower blood flow and lower ventilation to the top of the lung
421
Between the base and the apex, does blood flow or ventilation have a bigger difference?
Blood flow has ha more regional difference than alveolar ventilation
Ventilation has less of a slope compared to blood flow when comparing what happens at base and apex
422
How does blood flow and ventilation compare at the base of the lung?
a little bit more blood flow than ventilation
423
What is a normal PO2/PCO2 at the base of the lung
PO2= 90mmHg (a little lower than average)
PCO2= a little higher than 40mmHg
424
Where is the bottom of the lung in relation to chest landmarks?
Below the 5th rib
425
How does ventilation compare to perfusion in the apex of the lung?
Top of the lung has a little more ventilation than blood flow
426
What is normal PO2/PCO2 at the apex of the lung?
PO2= 130mmHg
PCO2= 30mmHg
427
How does V/Q ratio compare at the apex of the lungs to the base of the lungs?
Higher V/Q ratio at the apex
Apex is over-ventilated based on amount of blood flow
428
What is V/Q ratio at the base of the lung compared to average?
Lower than average
429
Where does expired air come from?
Average of air coming from the apex and base
(Apex: PAO2 130; Base: PAO2 90= around 100 average)
(apex PACO2 30; Base PACO@ higher than 40= around 40 average)
430
What is normal alveolar minute ventilation?
4200mL/min
431
When alveolar ventilation is normal what is the PAO2 and PACO2?
PAO2= 100mmHg
PACO2= 40mmHG
432
What happens to PAO2 and PACO2 in alveolar ventilation increases?
PAO2 increases
PACO2 decreases
433
What happens to PAO2 and PACO2 if alveolar ventilation decreases?
PAO2 decreases
PACO2 increases
434
How does ventilation compare for the apex and the base of the lung?
- Apex is over-ventilated for how much blood flow it gets
- Base is under ventilated for how much blood flow it gets
*Normal for healthy people to have these differencesâ disease exaggerates these differences*
435
___________ dead space can occur with anesthesia d/t prolonged positive pressure ventilation
Alveolar
436
Why is it important to account for alveolar dead space in patients?
Increased alveolar dead space need increased ventilation to get enough volume for alveolar ventilation and keep blood gases normal
437
How does age effect V/Q matching?
V/Q matching gets worse as a function of aging even entirely healthy
Healthy 20y/o: ventilation and blood flow curve are matched up
Healthy 44y/o: decreased alveolar ventilation, not much overlap with blood flow
438
What is this?
CT showing atelectasis of the lung
439
If a patient is awake and has a PaO2 of 92mmHg, what is a good guess of their age?
55y/oâ ventilation and perfusion curves are matched up pretty good
440
What happens almost instantaneously when a patient is induced, paralyzed, intubated and not using any PEEP?
No PEEP= lung collapse
V/Q are mismatched because airways arent being propped open and muscles are paralyzed
441
Why is it important to provide pressure to reopen a collapsed lung as soon as possible?
The longer the lung is collapsed the harder to get reopened (would need more and more pressure)
442
What does PEEP prevent?
Wide scale atelectasis and maintains adequate V/Q matching
443
How are alveoli connected to eachother?
Through neighboring pathways
444
How does a small alveoli pressure compare to large alveoli pressure according to LaPlace's Law?
Small alveoli pressure is predicted higher than large alveoli (if alveoli are not full)
445
According to LaPLace, if an alveoli is 10% full and is connected to another alveoli through a common pathway that is 50% full what will happen?
Smaller balloon deflated and air goes into larger alveoli because of the pressure that is dependent on the radius
Smaller radium= increased pressure
446
How is pressure in the alveoli calculated with LaPlaces law?
Surface tension (recoil) / Radius
447
How does LaPlace's Law predict alveolar air will move?
Air would move out of the smaller sphere (smaller radius= more pressure) into the larger spheres (bigger radius= less pressure) provided larger spheres arent filled 100%
If fresh air is coming in on common pathway then it will go to the side with lower pressure until 80-90% full then would go to less full alveolus
If we wanted to open up other alveolus more would have to increase pressure and air volume
448
What does LaPlace's Law predict about ventilation?
Ventilation is unevenâ fresh air only goes to alveoli that are already open
449
Why is LaPlaces law dangerous?
If we have to fill and alveolus up to 100% to get air into the collapsed part of the lung, it could cause full alveolus to get blown out by pressure and volume
If a lung is collapsed fresh air flows to lung that is open and we would have to use alot of pressure and volume to re-recruit collapsed lung
450
Why doesnt LaPlace's Law hold up under healthy conditions?
Surfactant in the alveoli helps to break surface tension to distribute things more evenly
451
How does alveoli size correlate with surfactant?
Fuller alveolus= More surface area for gas exchange and more surface area for gas to cover
Surfactant floating in the water of the alveoli gets diluted out the fuller the alveolus gets
452
What happens to effective biological concentration of surfactant with increased/decreased alveolar size?
Effective biological concentration of surfactant is reduced the fuller the alveoli are
Alveolus that is more empty= surfactant is not as spread out
Less surface area= higher effective biological concentration of surfactant in the alveolus
453
How are smaller alveoli ventilated under healthy conditions (debunks LaPlace's Law)?
Smaller alveoli have more concentrated surfactantâ makes it easier to put air into the alveolus
454
When would LaPlace's predictions hold true?
If a person doesn't have any surfactant
Any lung problem= surfactant deficiency
455
Without surfactant ventilation would be ____________.
Uneven
*uneven distribution of fresh air*
456
What happens to surfactant in lung regions that have been collapsed for a period of time?
Surfactant disappears because the macrophages eat it up
The longer you wait the harder it is to put air into collapsed parts of the lung
457
What is physiologic dead space?
Anatomical dead space + Alveolar dead space
458
What is the physiologic dead space in a young healthy person comprised of?
Anatomical dead space (should not have any alveolar dead space)
459
How is anatomical dead space estimated?
1mL/lb of ideal body weight
460
How much anatomical dead space would IBW of 150lb have?
150cc anatomical dead space
461
What are reasons for development of alveolar dead space?
- older
- under anesthesia
- harsh environment chemicals
- positive pressure ventilation
462
What happens to the lungs when alveolar dead space develops?
That part of the lung doesnt function for gas exchange
463
What is an important anesthesia consideration for patients on PPV?
Positive pressure ventilation can cause too much pressure in the lungs and makes blood flow through the capillaries difficult
464
What are steps to take if there is increased alveolar dead space in a patient?
Increase Vt to make sure enough air is getting to areas of the lung that are actually having good gas exchange
465
How can alveolar dead space be quantified?
Look at mixed expired gasâ collection of the entire expired breath including dead space
466
What does ME variable stand for?
Mixed expired air= alveolar + dead space air
467
What is the gas composition of anatomical dead space?
High O2 (150), No CO2 (0)
Should be same as atmosphere
468
What makes PEO2 the value that it is?
Between dead space PO2 and alveolar PO2
(150 and 100)
Expired PO2 is closer to alveolar PO2 because there is greater volume of alveolar PO2 than dead space
469
What is the value for PEO2 (mixed expired O2)?
120mmHg
470
What is the value for PECO2 (mixed expired CO2)?
27mmHg
Between 40 and 0â closer to 40 because there is more alveolar air than dead space
471
What is the value for PEN2?
566 mmHg
Should be the same as what is going into the lungs
472
What is the value for PEH2O?
47mmHg
473
If we have alveolar dead space in the lungs, what will happen to PECO2?
PECO2 will be lower than normal
The more dead space we develop the lower out PECO2
474
What is the PECO2 in a patient with normal Vt with normal anatomical dead space?
28mmHg
475
What is the PEO2 in a patient 500mL Vt and normal anatomical dead space?
115mmHg
476
What is the concentration of CO2 in normal alveolar air?
5.3%
477
How much CO2 is in normal alveolar air?
18.42mLCO2
478
What is the concentration of CO2 of mixed gas in the lungs?
3.7%
479
What is the FEF 25-75%?
Forced expiratory flow rate occurring during the middle part of the breath
Measure small airway reactivity
480
What position change causes the biggest change in FRC?
Supine to upright
481
What causes the reduction in FRC when laying down?
Reduced ERV
482
What volume changes in response to reduced ERV?
Increase IRV by the amount ERV was reduced
because TLC doesnt change
483
What can be looked at as an indicator of what is going on in the lungs?
Expired airâ snap shot of the conditions in the lungs over a period of time
484
If everything is normal in the pulmonary system then expired air should be roughly equivalent to ____________.
Arterial blood gases
485
What is the capnograph a value of?
PCO2 of expired air (PECO2)
486
What is the first part of the capnograph reading a result of?
Early portion of breath expired doesn't have any CO2 (Anatomical dead space empties first)
487
When does CO2 stars to show up on a capnograph?
Transitional phase- short lived when CO2 stars to show up in expired air
488
What is the phase on a capnograph after after the transitional phase?
Composition of lung airâ should be matched up with systemic arterial blood gases if there is no shunting or dead space problem
489
________ PCO2 should be close to capnograph ETCO2
ABGâ roughly 40 when everything is working right
490
Why is there a small slope up on a normal capnograph?
The slope is a function of time during expiration when deoxygenated blood is still being passed in the chest
Blood continues to move through the lungs and unload CO2 and absorbs O2
Over expiration
491
Alveolar PCO2 should be around _____.
40mmHg on average
492
When is alveolar PCO2 the lowest?
When fresh air hits the lungs
493
How long is normal expiration?
up to 2 seconds
494
What happens with pulmonary blood flow during expiration?
blood is still moving through and unloading CO2 into the air in the lungs
CO2 being constantly unloaded= higher PCO2 at the end of a 2-3 second expiration compared to PCO2 at beginning of expiration
495
When is PACO2 at its highest point in the lungs?
At the very end of the respiratory cycle before fresh air comes in
496
How can we figure out the quantity of CO2 between each breath?
3L in the lungs in between breaths
40/760= 5.263% = Fractional of alveolar CO2 (FACO2)
(Partial pressure of gas) / (total pressure of gas)
3(0.05263)= 158mL CO2
497
What is he asking for if he asks for quantity of a gas?
Volume
498
How much has FACO2 changed between FRC and taking one breath of fresh air
3,000mL + 350 mL (alveolar portion of Vt)= 3350mL
158mL/3350mL= 0.0471 or 4.71%
5.263% - 4.71%= 0.55%
499
What is the PCO2 in the lungs after a breath of air?
(0.047) x (760)= 36mmHg
500
What is the PCO2 5 seconds after fresh air has come into the lungs?
5 seconds to unload CO2 into the lung airâ expect increase in PCO2 as a function of time
44mmHg
501
How much does alveolar PCO2 fluctuate by from normal?
+/- 4mmHg
502
What would cause an inverted slope on capnograph?
Late-stage emphysemaâ lung compliance is very high and more prone to small airway collapse
- PCO2 in air coming from the apex is lower than normal
- PCO2 in air coming from the base is higher than normal
503
What happens on expiration in patients with severe emphysema?
Small airway collapsing
504
Which part of the airway are prone to collapsing first upon expiration in a patient with severe emphysema?
The earliest part of the lung to collapse is the base, the apex will collapse later
Reason is because base has smaller alveoli and smaller airways
505
Why is the mechanism of the inverted slope on capnograph with endstage COPD?
- Throughout expiration base of the lung is collapsing
- Leads to more CO2 coming from the top of the lung where CO2 concentration is lower
- shows up as inverted slope on the plateau of the capnograph
- Not usually seen with minor COPD usually with end stage
506
Capnographs are _________ from what is going on in the patient
Delayed
Doesnt instantly see what is coming off the patient there is a bunch of tubing that the expired air has to flow through which staggers/off sets the graph
507
Why does inspiration look like it starts early on the capnograph?
Capnograph is still working on the last round of expired air
Hasnt moved all the way through the tubing
508
What screens are most capnographs able to display?
- PCO2
- FECO2
509
Why is a moisture trap necessary for end tidal monitoring?
- Capnographs are sensitive to humidity
- Without moisture trap the humidified air is sucked into machine and messes up reading
510
What number do we look at to approximate conditions in the lungs?
EtCO2
511
How does alveolar dead space impact ETCO2?
Alveolar dead space empties at the same time as good alveolar gasâ can cause reduced end tidal CO2
Alveolar dead space air dilutes healthy alveolar air and reduces plateau line of EtCO2
512
Is there CO2 in alveolar dead space?
NO
513
What is a quick way to approximate how much alveolar dead space we have?
Look at EtCO2â can use as a gage to look at how bad things are getting
514
If a patient is on the vent for a period of time and the ETCO2 is reading lower CO2, what could this mean?
Probably alveolar dead space that is emptying at the same time as alveolar air
the longer you are on a vent, the more pressure you have to use to keep lungs open
515
What is another method (besides ETCO2) used to estimate alveolar dead space?
Bohn equation
516
Does any type of dead space have CO2?
No
517
Where does all CO2 that is expired come from?
Good alveoli that undergo gas exchange
All CO2 in a mixed sample is from alveoli that are ventilated and perfused
518
How do we calculate tidal volume?
VT= Va + VD
519
What does the variable "F" indicate?
Fractionalâ answer will be in a decimal
520
How do we calculate FCO2?
Partial pressure CO2 / total pressure
521
How do we get a number for PACO2?
Estimated with end tidal CO2
End tidal = whats going on in alveolus
522
If there is no shunt, ETCO2 should be about the same as ______
Arterial PCO2
523
How do we solve for total dead space?
VDCO2/ VT= (PaCO2 - PECO2) / PaCO2
524
What is physiological dead space in a healthy 20y/o?
150cc
Should not have any alveolar dead space, all anatomic
Negligible alveolar dead space
525
What is the compliance of the total system measuring?
Combination of the compliance of each part of the system
- The lung
- The chest wall
526
What 2 things in our chest create a barrier to putting air into the lungs?
- Lungs: want to recoil on themselves
- Chest wall: could get in the way depending on volume and position of pt
527
How would compliance change in a heavyy top set patient?
Harder to put air into the lungs (probably from reduced chest wall compliance)
528
How does laying on your back affect compliance in the lungs?
Chest wall compliance is reduced because there is extra eights sitting on the lungs
529
How is total compliance calculated?
530
__________ is a measure of how easy it is to get air in and out of the lung
Compliance
531
Where does the apex of the lung sit?
Above the 1st rib
532
What direction does the elastic tissue that makes up the lungs want to recoil?
Inward
PER (PEL)
533
What direction does the chest wall tend to recoil at FRC?
outward
534
Where is the pleural space?
Potential space between chest wall and lungs
535
What creates the -5cmH2O pleural pressure when the lungs are at rest?
- Chest wall wants to recoil outward at FRC
- Lungs want to recoil inward
Gives negative pleural pressure because the areas want to recoil in opposite directions
536
What happens to the chest wall is elastic recoil pressure is reduced?
Chest wall will expand outwardâ only think holding the chest wall in place was the lung inward recoil
If decrease recoil pressure then forces are out of balance
537
How do people with COPD/Emphysema gets barrel chest?
- Loss of elastic recoil
- chest wall protrudes out with less recoil opposing it
- rib cage protrude
- causes higher lung volumes
538
How is pleural pressure effected by lower recoil pressure?
Less opposition to outward recoil makes for a more positive pleural pressure (-2.5cmH2O)
Lung is really full but pleural pressure is more positive because we lack normal amount of elastic recoil in the lungs
539
How does lung volume correspond to transpulmonary pressure in pts with emphysema?
Large lung volumes= low transpulmonary pressure
doesnt take much pressure to fill the lung up
540
What would transpulmonary pressure be in a patient with emphysema to get to VC breath of 6L?
+10 cmH2O
541
What is a normal transpulmonary pressure to get the lungs to TLC?
+30 cmH2O
542
What is the formula for compliance?
(Change in volume) / (change in pressure)
543
How can we calculate pulmonary compliance at FRC?
Look at how pleural pressure changes when taking a breath (change in pressure)
Normal volume= VT (500mL)
Pulmonary Compliance at FRC= 0.2L/cmH2O
544
Why dose pulmonary compliance at FRC not take into account chest wall compliance?
Chest wall isnt in the way at FRCâ not opposing putting air in the lungs
545
Total compliance is ____________ than the compliance of either individual part
Lower
546
When would the chest wall create a barrier to putting air into the lungs?
If the chest wall didnt want to recoil outward like normal
547
Explain how the lungs are a system in series when the chest wall does not want to recoil outward:
- Pushing against tendency of the lung to stay at low volume
- pushing against chest wall
- one barrier right next to the other barrier = series
548
What is resistance?
How hard it is to push current through a compartment
549
How do we calculate total resistance for a system in series?
Sum of 2 partsâ have to move through both parts (no way around)
Rtotal= R1 + R2 (looking at resistance)
550
How do we calculate resistance for a system in parallel?
Option to move through either R1 or R2â total resistance is lower than each individual resistance since it has 2 options
1/Rtotal= 1/R1 + 1/R2 (looking at compliance)
551
How is the pulmonary system arranged?
Series: pushing against the lung tissue and the chest wall (if the chest wall is in the way)
552
What are some examples of when the chest wall would create a barrier to putting air in the lungs?
Fat/Heavyâ chest wall doesnt want to move out of the way for air
553
Compliance it looking at how _______ it is to put air into the lungs
easy
554
What is the formula for compliance when given resistance?
inverse
1/Rtotal= 1/R1 + 1/R2
555
_________ is the opposite of resistance
Compliance
556
The pulmonary system is in series and we use resistance formula to calculate pulmonary resistance....but we use formula for systems in parallel to calculate _______________
Compliance
557
What is normal chest wall compliance at FRC (Ccw)
0.2 L/cmH2O
558
What is normal compliance of the lung at FRC (Clung)?
0.2 L/cmH2O
559
What is compliance of the system at FRC (Ctotal)?
0.1 L/cmH2O
560
If resistance = 2 what is the total resistance of a system and what is the compliance of the system?
561
What happens if something (ex: blood/air) fills the potential pleural space?
Lose integrity of chest wall and the lung will deflateâ no more negative pleural pressure and it will be difficult to fill lungs with air
562
What is a pneumopthorax?
Opening when air is sucked into the pleural space and the lung recoils on itself making it difficult to ventilate
563
What is a hemothorax?
Blood in the pleural space and lung recoils on itself making it difficult to ventilate
564
How much O2 is in the lung in between breaths?
100/760= 13.16% O2
0.1316 x 3000 = 395mLO2 in the lungs at FRC
565
What pressure of O2 is in pulmonary venous blood leaving the lungs?
PO2= 100mmHg (O2 tension)
566
What is O2 tension?
Same thing as partial pressure of O2
567
What is the concentration of O2 in the lungs at FRC?
13.16%
568
What would we expect concentration of O2 in the pulmonary vein to be?
13.16%
569
What is typical O2 consumption?
250mLO2/minute
570
How much O2 reserve do we have in our lungs at FRC?
395mL O2 in lungs
Body need 250mLO2/min
395/250= 1.58 minutes without bringing in more air
571
How does O2 reserve differ for a patient who is anesthetized and on the OR table?
Nowhere close to 3L in their lungs
572
What happens to lung volume when someone is completely paralyzed?
Lung volumes can go below RVâ drop to around 1L
A lot less O2 buffer which is why we preoxygenate to build up reserve
573
What is the concentration of O2 in humidified air?
19%â displacement of O2 by water vapor
574
Which lung is larger? Why?
Right lung âLarger and heavier, has more volume than the left lung
575
How many lobes does the left lung have?
2 lobes
576
How many lobes does the right lung have?
3 lobes
-Superior
-Middle
-Inferior
577
What makes the left lung smaller than the right lung?
the heart
578
Which lung is taller?
Left lungâ heart pushes down on diaphragm
579
What is the term for the separations between the lobes of the lungs?
Fissures
580
How many fissures are in the right lobe?
2 fissures
581
What is the green circle showing?
Horizontal fissure of right lung
582
What is the pink circle showing?
oblique fissure
583
What is the blue circle on?
Visceral pleura
584
What is the red circle pointing to?
Parietal pleura
585
What is the name for subdivisions found within each of the lobes of the 2 lungs?
Bronchopulmonary segments
586
How many bronchopulmonary segments are in the right lung?
10
587
How many bronchopulmonary segments are in the left lung?
8
588
Connective tissue lining that is stuck on the lung itself:
Visceral pleura
589
Connective tissue lining on the inside of the chest with a thin layer of slippery fluid that allows lungs to move in the chest as it expands:
Parietal pleura
590
What causes the pain associated with lung infections?
- Inflamed larger airways
- lungs not sliding around in the chest how they should
591
How can lung inflammation cause issues with ventilation?
Can mess with the lungs ability to expand and contract as we bring air in and allow it back out
592
What is the pleural space?
Potential space: has a little fluid in it
593
What is the opening/space between the top of the diaphragm and the side of the rib cage?
Costodiaphragmatic recess
594
What is the pink circle pointing out?
Costodiaphragmatic recess
595
Where does the diaphragm fasten?
Base of the thoraxâ vertebral body of L1-L3
596
Which dome of the diaphragm is taller?
Right dome (heart weights on left)
597
What happens to the heart as we breathe?
The heart moves up and down with the diaphragm
598
Where does the diaphragm connect at?
The central tendon (where the heart sits)
599
What muscle(s) are involved in quiet breathing?
Usually just the diaphragm contracting and relaxing
600
How do the lungs normally get air out?
Rely on passive recoil when diaphragm relaxes with normal expiration to push the air out
601
How does the body assist when trying to get a deeper breath?
Relies on other muscles to help
602
What is the function of the scalene muscles?
Help hold the top of the thorax in position as the diaphragm contracts and drops and prevents the rib cage from being pulled down
Allows for more effective inspiration
603
Where are the scalene muscles connected?
Connected to cervical vertebrae and first 2 ribs
604
How many scalene muscles are there and where are they anchored?
3 sets of scalene muscles on either side of the neck
- Anterior Scalene: C3-C6, 1st rib
- Middle Scalene: C3-C7, 1st rib
- Posterior Scalene: C5-C7. 2nd rib
605
Where are the attachment points for the sternocleidomastoid?
Sternum and mastoid process of the skull
606
Where is the mastoid process located?
Behind the ear
607
What does contracting the sternocleidomastoid muscle do?
Helps prevent the rib cage from being pulled down with inspiration as the diaphragm contracts
608
Where are intercostal muscles located?
Between the ribs
609
How many intercostal muscles are there?
2 sets of skeletal muscles located within the rib cage
- External intercostal muscles
- Internal intercostal muscles
610
What is the function of the external intercostal muscles?
Located outer portion of rib cage (superficial)
- Attach to outer rib cage
- contracting external intercostal muscles expands the thorax out and brings it anterior
- Aids with inspiration
611
What is the function of the internal intercostal muscles?
Attachment points on the inside of the rib cage
- Contracting these muscles compresses the thorax and brings the thorax closer to midline
- Aid with forced expiration
612
When would the intercostal muscles be used?
Not used too much unless we are breathing at a much faster rate than normal
613
Which muscles are recruited when we want to push air our of the lungs faster than it wants to leave with passive recoil?
Abdominal muscles
614
What happens when abdominal muscles are contracted?
pushes contents in abdominal cavity up on the diaphragm and airs in pushing air our of the lungs
- aids with speed that we can expire
615
What muscles are included as abdominal muscles?
- Rectus Abdominus
- Obliques
616
What is the big superficial muscle on the outside top of chest?
Pectoralis major
617
Which muscle sits deep to pec major muscles and connects to the shoulder blades at the top of the rib cage?
Pectoralis minor
618
Where are the connection points for pec minor?
- Coracoid process of shoulder blade
- Ribs 3-5
619
If you are standing with your arms at your side and contract pec minor what happens?
Pec muscle will just pull down on the shoulder blades
620
What happens if you contract pec minor while you are leaning on your arms?
Leaning on your arms prevents the shoulder blade from moving down/holds thorax in place to make deep inspiration easier
gives diaphragm a good position to pull down from
621
What are the 3 parts of the upper airway?
Upper airway= pharynx
Nasopharynx: Top part opening in the nose
Oropharynx: Middle part, oral cavity
Laryngo-pharynx: Lower portion, Everything below oral cavity
622
Which portion of the pharynx attaches to the trachea?
Larynx
623
1?
Hyoid bone
624
2?
Laryngeal prominence
625
3?
Cricothyroid ligament
626
4?
Superior horn
627
5?
Thyroid cartilage
628
6?
Inferior horn
629
7?
Cricoid cartilage
630
What type of muscle is the tongue?
Skeletal muscle (same with muscles on the floor of the mouth)
631
What is a concern when paralyzing a patient laying on their back?
Tongue and muscles on floor of mouth relax and the tongue occludes opening of larynx
*tongue has nowhere to go but back*
632
What is the function of the bony projections in the medial part of the nose on either side?
Bone is porous and gives a place for all the blood vessels to sit in
633
The upper airway acts as a ________
Filter
634
What does the nose do to the air that we inhale?
Rapidly heats and humidifies inspired air almost immediately
Requires a lot of moisture and body head in the nose
635
How does the body get heat and moisture to the nose?
Rich blood flow to the nose
636
What happens to the upper airway of we dont humidify the air that is coming in?
Larynx and trachea would be dried out (upper parts of respiratory system)â could cause a problem if they get too dried out
Lungs wouldnt get dried out
637
Where are blood vessel in the nose located?
On top of the porous bone
638
What are the bony projections in the nose called?
Concha or Turbinates
639
How many sets of concha are there?
3 sets: One on each side of the nose
640
How are the concha shaped?
All are curvedâ inferior concha more curves than upper ones
641
What is the superior concha a projection of?
Ethmoid bone on each side of the nose
642
What is the middle concha a projection of?
Ethmoid bone on each side of the nose
643
What is the inferior concha a projection of?
Projection of maxillary boneâContinuous with the roof of the mouth/ hard palate
644
Which concha are the sturdiest?
Lower concha: reason why you try to run nasal airway on the floor of the nose (fairly flat)
645
What is the access point for nasal intubations?
Floor of the nose to insert airway underneath inferior concha
646
What is the function of the concha?
Each is curved and used to generate turbulence as we inspire through the noseâ this is good because the air runs into the walls of the nose where there is mucus and particulates that are inspired can get stuck
647
What type of particles does mucus in the nose trap?
Large particles (dust/pollen)
Does not trap smoke because its small particles
648
How much air is inspired through the nose in a healthy adult?
Half of the air through the nose and half through the mouth on inspiration
649
Where does the ethmoid bone sit?
Middle of the face behind the opening of the nose (VERY fragile and easy to snap things off)
650
What is the upper mouth where the teeth are anchored into?
Maxillary bone
651
Why do sinuses become an issue when someone is sick?
Sinuses are surrounded by flesh materialâ if sick the sinuses can get a bunch of junk in them making it hard to breathe
652
What is the downside to porous bones in the nose?
Makes bone more fragile and more prone to fracture
653
What is important to do during nasal intubations?
Stay away from the top of the nose, stay along the floor on the nose
Be very careful to not snap a bone: would cause bleeding and they are supine so the blood would flow to their airway
654
Label each circle
- Green
- Purple
- Orange
- Blue
- Pink
Green: Crista Galli
Purple: Cribriform plate
Orange: Superior concha
Blue: Middle concha
Pink: Inferior concha
655
What is the upward projection midline on the ethmoid bone? what is the function?
Crista Galli: Connection point for Falx cerebri
656
What bone is this? What view is this? Label:
Ethmoid Bone
Anterior view
A) Crista Galli
B) Middle concha
657
What bone is this? What view? Label:
Ethmoid Bone
Posterior view
A) Crista Galli
B) Middle Concha
C) Superior Concha
658
What is the function of the Falx cerebri?
Connective tissue that separated left and right hemispheres
659
What is cranial nerve V?
Trigeminal Nerve
660
What are the 3 branches of the trigeminal nerve (sensory)?
Opthalamic division (V1): forehead
Maxillary division (V2): Upper mouth
Mandibular division (V3): Jaw
661
Are there nerves on the roof of the mouth?
Yes
662
How does a brain freeze work?
Cold temp sensed by nerve on roof of mouthâ the brain feels pain but is confused where from â trigeminal nerve interprets coldness at roof of mouth as headache (felt on forehead)
Fastest way to get rid of a brain freeze is put tongue on roof of mouth to warm it up
663
What this?
A) Ethmoid bone
B) Mastoid Process
664
Where are smell sensors routed in the nose?
Ethmoid boneâ large portion that are porous sand give route for smell sensors to pick up scents in the nose and relay to the brain
Smell sensors sit at the top of ethmoid bone and have growth projections that wing through the holes of ethmoid bone and position at the top of the nasal cavity
665
What area do olfactory neurons work their way into the nose so we can smell?
Cribriform plate of the ethmoid bone
666
Neurons in the nose have a ________ connection to the brain
Direct
Drugs are easily absorbed in the nose bc highly vascular and neurons that have a direct connection to the brain
667
A) Cribriform plate of ethmoid
B) Crista Galli of ethmoid
668
Where does the trigeminal nerve innervate in the upper airway ?
Oropharynx and back part of nose
Front 2/3 of tongue sensory info (V3)
669
Where does the vagus nerve innervate in the upper airway?
Back of oropharynx and down through larynx (sensory function)
And sensory function throughout the trachea and epiglottis
670
What is the big piece of cartilage at the base of the tongue that closes the airway when we swallow?
Epiglottis
671
Where does the glossopharyngeal nerve innervate in the upper airway?
Sensory function for anterior epiglottis
Sensory function for back 1/3 of tongue and back of mouth
672
There arent a lot of taste sensations on the epiglottis, but if there was it would be controlled by the ________ nerve
Vagus
673
What controls somatic and taste sensation for the back 1/3 of the tongue?
Glossopharyngeal
674
What controls taste sensation for the front/anterior 2/3 of the tongue?
Facial nerve
675
What nerve controls front 2/3 somatic sensation to the tongue (pain/itch)?
Trigeminal nerve (V3)
676
What nerve controls somatic sensation to the epiglottis?
Vagus nerve
677
Which nerve serves highlighted area/function?
A) Vagus
B) Glossopharyngeal
C) Vagus
D) Glossopharyngeal
E) Facial
F) Trigeminal V3 mandibular region
678
What is the name of the roof of the mouth that has a bony hard structure to it?
Hard palate
679
What is posterior and inferior to the hard palate?
Soft palate
680
Piece of soft tissue that hands off the back of the hard palate:
Soft palate
681
What usually makes people snore and can cause difficult airways?
When too much of the soft palate is hanging off the hard palateâ more difficult to access airway and causes snoring
682
What is the projection off the middle of the soft palate?
Uvula
683
684
What sits behind the uvula?
Tonsils
685
Which tonsils are above the soft palate?
Palatine tonsils
*a little above the lingual tonsils*
686
Which tonsils are located in the nasopharynx at the back of the nose and behind the soft palate?
Pharyngeal tonsils
687
Are the palatine tonsils above the lingual tonsils?
Yes
688
Which tonsils are situated at the back of the tongue?
Lingual Tonsils
689
Whats this?
Enlarged palatine tonsils
690
What is circles in blue?
soft palate
enlarged pharyngeal tonsil behind soft palate
691
What happens if Pharyngeal tonsils are enlarged?
Create an issue with breathing by pushing the soft palate forward
Would need tonsilectomy
692
A) Lingual tonsil
B) Epiglottis
C) Cricoid cartilage
D) Thyroid cartilage
E) Hyoid bone
693
A) Palatine tonsil
B) Lingual Tonsil
C) Epiglottis
D) Cricoid cartilage
E) Uvula
F) soft palate
694
What glands are responsible for making saliva?
- Sublingual glands
- Submandibular glands
- Parotid gland
695
Where are sublingual glands located?
Underneath the front of the tongue
696
Where are submandibular glands located?
Underneath mandibleâ further to the rear at the base of the jaw
697
Where are parotid glands located?
On either side of the face (common to swell when its hit)
698
What makes the salivary glands prone to swelling if damaged?
Highly vascular with lots of blood vessels
699
Which gland is circled in pink? Which gland is circled in blue?
Pink: Parotid gland
Blue: Submandibular gland
700
Which gland is circled in green? Which gland is circled in orange?
Green: Submandibular gland
Orange: sublingual gland
701
What is the larynx made up of?
Cartilage help together by connective tissue
702
What is the top tissue of the larynx?
Epiglottis (protrudes from behind the tongue)
703
What is the opening immediately to the front of the epiglottis (where you would want to position the curve of the MAC blade)?
Vallecula
704
Which laryngoscope is better for repositioning the tongue?
MAC blade
705
What are the 2 ways the epiglottis can cover the airway when swallowing?
- Epiglottis is pulled back to block the opening
- The rest of the larynx moves up
706
What does clearing your throat do?
Moves junk coughed up from your lungs in the larynx to the esophagus so the body can recycle the mucus
707
Where is mucus from the lungs cleared?
the larynx
708
What is the name of the floating bone underneath the mouth above the larynx? What is its purpose?
Hyoid bone: serves as an attachment for muscles in the floor of the mouth and pieces of cartilage in the larynx
709
Can the hyoid bone break?
Yes, but the cartilage in the larynx cannot
710
What is the only bone in the larynx?
The hyoid boneâ the rest of the larynx is made up of cartilage which prevents fractures in the larynx
711
What is the narrowest point of the adult upper airway?
Space between the cordsâ Transglottic space
712
How is the esophagus positioned in relation to the larynx?
Posterior to the larynx
713
What is the purpose of cricoid pressure?
A way to prevent gastric contents from entering the larynx
714
How does cricoid pressure work?
Pushing on front of cricoid cartilage should push part of cricoid cartilage into position that closes off esophagus and helps prevent aspiration
715
What is a downside to cricoid pressure?
If the patient is awake at all or muscle spasms in abdomenâ lower esophageal sphincter is not use to increase pressure and if stomach pressure rises it can blow out the LES and cause permanent damage
716
What is the greatest pressure the LES is usually subjected to?
Vomiting (really not use to increase pressure)
717
What is the blue circle highlighting?
Vallecula (below lingual tonsil and above epiglottis)
718
Where is the laryngeal cartilage located?
Underneath the soft tissue of the larynx
719
What is the large piece of cartilage that makes up the bulk of the larynx?
Thyroid cartilage
720
What are the attachment points for the thyroid cartilage?
Hyoid bone above it and trachea below it
721
Name for the joint that allows the thyroid cartilage to pivot inferior (down):
Cricothyroid joint
722
What is the connection point for thyroid cartilage and cricoid cartilage?
Cricothyroid joint
723
Where does the cricothyroid joint connect to the thyroid?
At the inferior horn of the thyroid
724
Ringed cartilage at the bottom below the thyroid cartilage:
Cricoid cartilage
725
A) Superior Horn
B) Thyroid cartilage
C) Cricothyroid joint
D) Cricoid cartilage
E) Laryngeal prominence
F) Epiglottis
726
What is the name for projections of cartilage coming off a larger body? What are these called in the spine?
- Horns
- Processes
727
What is the smooth surface on either side of the thyroid cartilage called (also where the thyroid gland sits next to)?
Lamina
728
Name for the cartilage projections coming off the back of the thyroid cartilage: What is the connection point?
Superior horns (connection point with hyoid bone)
729
Name for the place where vocal cords are attached at the front medial portion of the larynx:
Laryngeal prominence
730
What causes men to have lower pitch voices>?
Longer distance with adams apple protruding further out= longer vocal cords and lower pitch
731
What is the length of acoustic guitar string?
3.5ft= higher pitch than bass guitar which has way longer strings
732
What piece of cartilage is this?
Thyroid cartilage
A) Superior Horn
B) Inferior horn
C) Left lamina
D) Laryngeal prominence
E) Right lamina
733
Which cartilage is ringed/continuous?
Cricoid cartilage
734
Name for place where inferior horn of thyroid cartilage attach:
Articular facet for thyroid cartilage (2)
735
What is the term for a divot in cartilage where there is a place for 2 things to come together?
Facet (similar to ribs in thoracic spine)
736
What are the large sides of the cricoid cartilage called?
Lamina
737
What is the cartilage that are attached to the vocal cords and cricoid cartilage?
Arytenoid cartilage
Have a joint for arytenoid cartilage to pivot and move around so we can phonate
738
What is the narrowest point in the upper airway of a patient < 10y/o?
Cricoid cartilage
739
What cartilage is this?
Cricoid cartilage
Blue: Articular facet for arytenoid cartilage
Green: articular facet for thyroid cartilage
740
What cartilage is this?
Cricoid cartilage
Blue: Articular facet for arytenoid cartilage
Green: articular facet for thyroid cartilage
Red: Lamina
741
What cartilage?
Cricoid cartilage
Blue: Articular facet for arytenoid cartilage
Green: Articular facet for thyroid cartilage
742
Diamond shaped cartilage that have a place where vocal cords attach to:
Arytenoid cartilage
743
Where do arytenoid cartilage sit?
Pivot point on cricoid cartilage (articular facet for arytenoid cartilage)
744
Very small cartilage that is basically fused to arytenoid cartilage:
Corniculate Cartilage
745
What 3 pieces of cartilage in the larynx are unparied?
- Thyroid cartilage
- Cricoid cartilage
- Epiglottis
746
What are the 2 pieces of cartilage discussed in lecture that are paired?
- Arytenoid cartilage
- Corniculate cartilage
also cuneiform cartilage (not discussed)
747
What are the muscle in the larynx that determine tension on the vocal cords and how open or closed the cords are?
Laryngeal muscles (small skeletal muscles)
748
What is the most external laryngeal muscle?
Cricothyroid muscle
749
What is the function of the cricothyroid muscle?
- Helps larynx pivot forward when this muscle contracts
- fastens cricoid cartilage to thyroid cartilage
750
What happens when the cricothyroid muscle contracts and pulls the front of the thyroid cartilage down via cricothyroid joint?
Tightens the vocal cords
751
What are the blue circles showing?
Vocal cords
752
What is each color?
Yellow: Thyroid cartilage
Blue: cricoid cartilage
Red: arytenoid cartilage (corniculate on the tip)
Green: vocal cords
Pink: vocal cord attachment on laryngeal prominence
753
How many sets of muscles have effect on tightness of the cord and whether the cords are open or close?
6 sets of muscles (swivel, pivot the arytenoid cartilage to help control when we are trying to speak)
