Pulmonary Anatomy and Physiology ppt Flashcards
1
Q
Just a quick reveiw of some anatomy, he said it is just info but I thought it would be good to know your BASIC anatomy prior to becoming a lung master!!!!
what makes up the thoracic cage?
what is the thoracic cage for?
A
-12 thoracic vertebral bodies, the ribs, and the sternum
protection and pliability
2
Q
Just a quick reveiw of some anatomy, he said it is just info but I thought it would be good to know your BASIC anatomy prior to becoming a lung master!!!!
- what is a useful landmark b/c it corresponds to the mid portion of the trachea? (which as we all know is the desirable location for the distal tip of the tracheal tube)
- the trachea is fibromuscular. how long is it? and what is it’s diameter?
- the trachea beagins at what vertebra?
- it bifurcates where? (name and location)
- the right main stem bronchus extends approx ____cm before it’s initial division into the bronchus to the right, upper and missle lobes?
- The left mainstem bronchus extends approx ____ cm before its initial division.
- 1/250-1/50 people have and anomalous what?
A
- the 2nd thoracic vertebra
- 10-12 cm long, 20 mm diameter
- 6th cervical vertebra
- at the carina, 5th thoracic vertebra
- 2.3 cm
- 5 cm
- RUL bronchus above the carina
3
Q
what degree do the bronchus take off at?
right?
left?
A
right-250
left- 450
4
Q
do the bronchioles have cartilage like the bronchi??
A
no that would be silly
5
Q
The “air” transfers from the bronchi to the bronchioles then divide to transitional resp bronchioles. during all of this what happens to caliber and total airway area?
A
the caliber decreases and the total airway area increases!
(sounds confusing but this is what i found when I looked it up…so basicaly we are going from a Large diameter (caliber) bronchi to the smaller bronchioles. althought the diameter or caliber gets smaller teh actual surface area is larger, b/c there are more bronchials kind of like the alveoli have a huge surface area dispite being smaller than a freckel on an ants pecker)
6
Q
what is between the visceral and parietal pleura and why?
A
a thin layer of fluid to allow the lungs to move in a smooth motion
(visceral is toward the organ (lung) and the parietal pleura is toward the rib cage)
7
Q
what occurs with negative pressure in the lungs?
A
the lungs expand and the layers are approximated
8
Q
Note position of lungs
anterior
A
9
Q
Note position of lungs
right side
A
10
Q
Note position of lungs
left side
A
11
Q
As stated previously notice the different bronchi and see the 250 right vs the 450 left and the cm difference between the first branches
A
12
Q
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what do we do if a pt gets over constriction? like an analphalaxis response or a recative airway?
A
we either want to OVERDRIVE the sympathetic side (our beta agonist) or give epinephrine
or we want to KNOCK OUT the parasympathetic side- atropine, glycopyrrolate, atrovent (anticholinergics)
side note- the reason we do this is because this is b/c when they are having a airway issuse that is causing the lungs to constrict is it PNS not SNS so we need to stop it or overcome it
13
Q
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as the last slide stated if we are having a constrictive airway problem we are having a PNS response. This slide will tie in with it and show why the smooth muscle is PNS controlled
So what are the 4 ways that airway smooth muscle is controlled (basically what controlls the resistance in the airway smooth muscle)
A
- Humeral and neural influances
- Rich PARASYMPATHETIC innervation (ACh)
- ß2 receptors- smaller airways
- NANC receptors (NonAdrenergic NonCholinergic)- histamine H1 and H2, substance P
14
Q
- Increases in lung volumes are accompanied by increases in what?
- As lung volumes decrease below FRC significant increases in what occurs?
A
- airway diameter
B/c the airways are tethered by the surrunding lung parenchyma.
- airway resistance
15
Q
pharmacological blockade of the PNS pathways or surgical transection of the vagus nerves can cause what in the lungs?
A
bronchodilation
(remember what i said earlier, to overcome the airway resistance you must increase SNS or block PNS)
16
Q
the NANC stimulation of the airway smooth muscle realeases H1 and H2. what do each do? and which one prevales?
A
H1 receptors -bronchoconstriction
H2 receptors- Bronchodilation
but regardless the predominant effect is bronchoconstriction
17
Q
Inhaled gases are warmed, filtered and humidified by what?
A
the nasal vascular mucosa (your god damn nose)
18
Q
the nose can heat the filtered air within __0C of body temp.
(i found this kinda of crazy. the nose is kind of like an instant warmer)
A
10C
33.8oF
19
Q
The nose humidifies the air to almost _____%
A
100%
20
Q
What in the nose is for mucous and particle removal?
A
Nasal cilia
21
Q
what can supress the cough reflex? and what can this lead to?
A
the administration of
general anesthesia
local anesthesia to the airway
opiods
benzodiazepines
-leads to the impaired clearance of secretions and foreign material from the airway
22
Q
the cough reflex is mediated by what? and from where? so it is controlled by what part of the ANS?
A
vagus mediated
from the medulla
PNS
23
Q
What actually occurs with a cough? or the basic 3 steps in a cough reaction
A
deep inspiration ⇒ glottic closure ⇒ forceful expiration (a cough0
24
Q
the Sneeze relex (or nose cough as I like to call it) is similar to a cough with what exception!!!
this is a gimme come on you know it!!!
A
it facilitates the clearance of secretions from the nasal passageway, rather than the passageway below the nose
25
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what is the chief muscle of breathing?
The diaphragm
26
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the diaphragm accounts for approximately \_\_% of the air that enters the lungs during spontaneous inspiration.
75%
27
how does the diaphragm cause gas to flow into the chest?
by decreasing intrathoracic pressure to less than atmospheric pressure
28
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the diaphragm does what to abdominal contents during inspiration?
downward and forward
29
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what is the usual (average/normal) diaphragm excursion?
1-10cm
30
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what in the spinal cord is the diaphragm controlled? and by what nerve?
cervical roots 3-5
the phrenic nerve
\*\* a way to remember 3,4,5 keeps the lungs alive\*\*
31
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some defining characteristics of the diaphragm
what type of nerves?
in controlled by what part of the cell?
rich in what?
and is vascularity?
***_what type of nerves?_*** slow twitch
***_in controlled by what part of the cell?_*** mitochondria
***_rich in what?_*** myoglobin
***_and is vascularity_***? highly vascular
32
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what do the external intercostals do?
contract to assist with inspiration
(a small amout)
\*\*how to remember EXternal INspiration
INternal EXperation
EX-IN
IN-EX
33
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What do the internal intercostals do?
the Tension (he uses this word and not the word contraction frther explanation will follow) allows retraction during exhalation
---the book states (this is why i think the word tension is more important than contraction) normal exhalation is a passive event utilizing the elastic recoil of the lungs, chest wall, and abdominal structures.
\*\*how to remember EXternal INspiration
INternal EXperation
EX-IN
IN-EX
34
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Inhalation is chiefly a result of what??? but there is some _______ intercostals as well.
Diaphragm
external
35
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inhalation provides what type of tension??
and to what organs/tissue??
ACTIVE
to the thoracic and lung tissue
\*\* i didn't know exactly what this "active" tension was so here it is-
Active tension-- derives from the interaction between myosin and actin active tension.
Passive tension-- can develop in the muscle's complex connective tissue.
36
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what is the normal resting tension in the lungs??
what is the MAX INSPIRATION tension?
***Normal*** -4 mmHg
***Max*** _\>_ -12 mmHg
37
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exhalation is primary passive. Why is this?
bc exhalation results from a recoil of tension
38
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An important additional exhalation mechanism (deflating force) is the surface tension of the fluid lining in the alveoli what are the 2 parts that cause this and what is the ratio of the parts to that allow this to occur?
Lung elastic fibers 1/3
surface tension/surfactant 2/3
I know this is real confusing but he said it was important on page 900 of S&H and ppt slide 13 may be some (but trust me) very little further assistance
39
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what are the most important muscles for forced exhalation or exhaltion during exertion (either way you want to look at it)
Abdominal muscles
40
What law describes surface tension properties mathmatically?
Laplace's law
41
What does laplace's law state? and give an example
1. The pressure to expand is directly proportional to tension/radius
2. ex. the pressure inside the bubble (alveoli) necessary to keep it expanded is directly proportional to the tension on the wall of the bubble (which tends to collapse it) divided by the radius of the bubble.
42
What results from the attraction between the molecules of the fluid film that lines the alveoli (tends to reduce the alveolar diameter)
surface tension
43
What helps to stabilize the sizes of the alveoli, reducing the surface tension in the larger alveoli to a lesser extent than in smaller alveoli? The net effect is maintenance of consistent alveolar diameter and stability
pulmonary surfactant
44
Surface tension is greater when fluid molecules are what?
closer together
b/c remember the definition of surface tension is--
What results from the attraction between the molecules of the fluid film that lines the alveoli (tends to reduce the alveolar diameter)
45
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when the surface area of the surfactant film is kept small, a rearrangemnt of molecules occurs, causing surface tension to ***_\_\_\_\_1\_\_\__*** with time. Therefore, peripheral alveoli tend to _***\_\_\_\_2\_\_\_\_***_ during prolonged periods of shallow breathing?
so basically smaller and smaller (tidal) volumes equals _***\_\_\_\_3\_\_\_***_
1. Increase
2. collapse
3. Collapse (atelectasis)
46
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when the surface area of the surfactant film is kept small, a rearrangemnt of molecules occurs, causing surface tension to **_increase**_ with time. Therefore, peripheral alveoli tend to _**collapse_** during prolonged periods of shallow breathing.
so basically smaller and smaller (tidal) volumes equals **_Collapse (atelectasis)_**
since we know know all of this is true!!!! what can WE do immediatly to increase their surface area, thus restoring normal surface tension?? 3 things? and in doing these things what is the main goal of this treatment.
1. A single large breath
2. Vital capacity maneuver
3. Sigh
The main goal is to RE-EXPAND these alveoli
47
what promotes fluid movement into the alveolus?
the tension
48
Surfactant
1. Made up of what?
2. secreted by what?
3. 1st produced when?
4. what does it do?
5. what 3 things make it decrease?
1. Lipoprotein
2. Pneumocytes
3. 28-32 wks gestation
4. decreases surface tension to physiologic levels
5. -100% O2
- smokers
- after CPB (coronary pulmonary bypass)
49
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the less the alveoli expand the more they want to do what
contract
50
we now know that tension allows fluid movement into the alveoli, but what keeps extra fluid out of the alveoli?
colloid osmotic pressure- it keeps the fluid intravascular
51
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1. with mechanical ventilation which alveoli expand more? apical or basal?
2. with spontaneous breathing which alveoli expand more?
3. this regional ventilation is all based on ________ in alveolar size?
1. apical alveoli expand \> basal
2. Basal alveoli expand \> apical
3. Change
52
the Basal alveoli has a greater change in size with what type of ventilation
spontaneous
(thus apical alveoli has a greater change in size with mechanical ventilation)
53
What is the total amount of gas moved into the lungs in a minute?
(it represents the total amount of gas moved into the lungs each minute)
Minute ventilation
54
how do you calculate minute ventilation
TV x frequency of breathing
55
the average minute ventilation is what?
6 Liters
56
what is more important that MV, But we use minute ventilation instead b/c this is too hard to calculate
alveolar ventilation
57
what is alveolar ventilation
the volume of gas each minute that enters those areas of the lungs caple of participating in gas exchange with pulmonary capillary blood
58
why is the alveolar ventilation less than MV?
b/c a portion of the inhaled gases resides in those areas of the airway (dead space est to be 150ml) that do not participate in gas exchange with pulmonary capillary blood
59
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Alveolar Ventilation
1. Is what?
2. Is less or more than MV?
3. how is it calculated?
4. average is what?
5. What 2 things are determined via the alveolar ventilation?
1. Gas capable of participating in gas exchange
2. less than MV
3. TV-dead space x RR
4. 4.2 L/min
5. PaCO2 and to a lesser degree PaO2
60
Hypercarbia increases _____ HTN and dilates vessels in the head leading to increased \_\_\_
pulmonary
ICP
61
2 types of dead space
1. Anatomic
2. Physiologic
62
what is the anatomic dead space? what is included in it?
* The areas of the respiratory tract that do not normally participate in gas exchange with the pulmonary capillary bed.
* Includes the
* nasal passage
* pharynx
* trachea
* bronchi
63
what is Physiologic dead space?
* simple definition
* non-perfused alveoli
* More detailed definition
* the gas volume of the alveoli that are not functional or only partially functional b/c of absent or poor blood flow through corrosponding pulmonary cappilaries (wasted ventilation)
64
what is the average amount of dead space in an adult?
2 mL/kg or approximately 150 mL
65
does dead space contain and nitrigen?
nope
(i just thought that was odd so I put it here)
66
During exhalation gas in the _***\_\_\_\_\_1\_\_\_\_\_\_***_ is exhaled before gas comming from the ***_\_\_\_\_\_2\_\_\_\__***
1. dead space
2. alveoli
67
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an alveoli that is not ventilated is called a what?
Shunt
68
with dead space ventilation what is this and say why??
Normal
b/c you have normal perfusion and normal blood flow!!
69
with dead space ventilation what is this and say why??
Shunt
b/c No ventilation and normal perfusion
70
with dead space ventilation what is this and say why??
Dead Space
b/c normal ventilation but No perfusion
71
with dead space ventilation what is this and say why??
Dead Unit
b/c No ventilation and No perfusion
72
Control of ventilation is via what 2 types of control?
neural
chemical
73
Ventilation will adjust in response to what 3 things in the body?
PaO2
PaCO2
and
H+ ion concentrations
74
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the major factor in regulation of alveolar ventilation in the \_\_\_\_1\_\_ rather than the \_\_2\_\_\_
1. PaCO2
2. PaO2
75
so we just learned that the major factor in regulation of alveolar ventilation is the PaCO2 rather than the PaO2. the is shown as the following. a 50% increase in PaCO2 evokes a ______ increase in alveolar ventilation, and a PaO2 of 40 mmHg only evoke a ______ increase in alveolar ventilation
ten-fold
1.5-fold
76
the FINE control of ventilation is provided by the respiratory center under the influance of chemical stimuli from what???
chemoreceptors
77
How does the medullary vasomotor center communicate with the repiratory center to influance ventilation??
2 ways
1. decrease in systemic B/P evoke a SNS activity (from vasomotor center)this causes an increase in alveolar ventilation
2. Hyperthermia directly and indirectly increases ventilation
78
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the respiratory center is located bilaterally in the reticular substance of the what?
medulla oblongata and pons
79
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the inspiratory area of the respiratory center does what? For a bonus where is it located?
rhythmic (insiratory) cycles
bilat in dorsal portion of medulla
side note it is vagal modulated
80
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the Pneumotaxic area of the respiratory center does what?
determines the duration of the inspiration
(in other words triggers the termination of inspiration)
81
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when does the apneustic center kick in? what are its characteristics?
only works if there is no pneumotaxic area stimulation
the pattern is maximal lung inflation with occasional breif expiratory gaps (apneuses)
82
The inflation and deflation reflexes on ventilation control are controlled by what?
vagal stretch receptors
83
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in regards to the expiratory area of the ventilation controll center.
what is it normally doing?
When does it become active?
inactive
with increased alveolar ventilation
84
the chemical control of ventilation adjust respiration to maintain a constant \_\_\_1\_\_\_\_, to defend against excessive changes in \_\_2\_\_ comcentrations and to prevent a dangerous decrease in \_\_\_3\_\_\_
1. PCO2
2. H+ ion
3. PaO2
85
what are the 2 chemoreceptors that regulate the chemical controll of ventilation?
1. medullary chemorecptors
2. Peripheral chemoreceptors
86
where are the medullary chemoreceptors located
a few microns below the medulla (basically in the medulla)
87
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the medullary chemorecptors
1. Most responsive to what?
2. Why are they most response to that?
3. How does the CO2 stimulate the chemosensitive area of the medulla?
1. CO2 concentrations
2. b/c the H+ ions can't easily cross BBB
3. CO2 crosses BBB ⇒ mixes with H2O ⇒ forms Carbonic acid (H2CO3) ⇒dissociates into H+ ions (H+ and HCO3)
(this is that whole equation that shores taught us) shadush bitch putting it all together......
88
\_\_\_ to \_\_\_% of the ventilatory response from the medulla is in the response to CO2
70-80%
89
the changes of H+ ion concentrations in the CSF occurs within \_\_1\_\_\_\_, and is much \_\_2\_\_\_\_ in interstitial fluids
1. seconds
2. slower
90
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where are the peripheral chemoreceptors located
carotid and aortic bodies
91
which peripheral chemoreceptors respond to the hypoxic ventilatory response
carotid bodies
92
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In the carotid bodies (hypoxic ventilatory response)
1. hypoxic ventilatory response transmits through what nerve?
2. it responds to what very rapidly?
3. this hypoxic ventilatory response is inhibited by what?
1. glossopharyngeal nerve
2. PaO2 (not SaO2)
3. VAA
93
Which peripheral chemoreceptor is not ad involved with the ventilatory response?
Aortic bodies
94
the peripheral Chemoreceptors that are located in the aortic bodies
1. transmitt thorugh what nerve?
2. and is more prominent in what response?
1. vagus
2. CV response
95
interesting fact
i stated that it is the PaO2 not the SaO2 (arterial hemoglobin saturation) that determines the stimulation level of the peripheral chemoreceptors.
this is the reason that anemia or carbon monoxide poisioning, inwhich the amount of dissolved oxygen and the PO2 remains normal, do not stimulate alveolar ventilation via the chemoreceptors.
(just for knowledge)
96
The regulation of pulmonary blood flow is what? but can also can be affected by what?
passive
O2 and C02
97
there is a anatural anatomic shunt of what % of CO
2-5%
98
what do all the lymphatic vessles do?
remove particulate and protein
99
pulmonary b/p is ___ that of systemic b/p
thus is a persons systemic B/P is 100 systolic what would you expect it to be in the pulmonary system
1/5
20
100
Normal PAP is what?
normal PAP mean is what?
PAP= Pulmonary Artery Pressure
22/8
13
( remember how to calculate MAP)
(dys x 2) + Sys / 3
so
((8 x 2) + 22) /3
16+ 22 = 38
38 / 3= 12.666666 =13
so remember the PAP and you can figure out the MAP
101
PAOP pressure in normally what?
PAOP= pulmonary capillary pressure/ or pulmonary capillary wedge pressure or PCWP (also called the pulmonary wedge pressure or PWP, or pulmonary artery occlusion pressure or PAOP
10 mmHg
102
what is the mean pressure in the pulm veins?
4 mmHg
103
the resistance to blood flow in the pulmonary circulation is about ______ the resistance in systemic circulation
1/10th
104
how do you estimate the LAP?
usually the PAOP is 2-3 mmHg higher than the LAP
105
what can increase LAP??
anything that is distal to the LA
for example mitrsl stenois
LVH
Increased SVR
Mitral Regurg
Aortic Stenosis
Aortic regurg
106
WHat is higer LAP or RAP
LAP
107
Pulmonary blood flow is greatest where? give examples
in dependent areas
posterior lungs (when supine)
bases (when standing)
108
Optimal oxygenation requires what?
V/Q matching
109
what is perfusion with suboptimal ventilation
shunt
110
What is ventilation with suboptimal perfusion?
dead space
111
Suboptimal ventilation and perfusion equals what?
dead unit
112
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what evokes Hypoxic Pulmonary Vasoconstriction?
give the actuall numbers also
alveolar hypoxia
which is a PaO2 \< 70 mmHg
113
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what is HPV
when alveolar hypoxia (PaO2 \<70 mmHg)is sensned it evokes vasoconstriction in the pulmonary arterioles supplying the affected alveoli; the net effect is diverted blow flow away from the poorly ventilated alveoli, as a result the shunt is minimized, and the resting PaO2 is maximized
114
A PaO2 of what evokes HPV?
\<70 mmHg
115
what is uniqe about HPV and how is occurs???
it is locally mediated!
this means that it can occur in denervated lungs
so basically even if you have a lung transplant you still get this response.
(i think thats pretty badass)
116
HPV is inhibited by what?
VAA (in animal models)
vasodilators
117
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what is normal VQ mismatch?
and how is that determined??
what is it's connection to PaO2
what does the formula ?/? mean
0.8
vent over perfusion is 4/5 or 0.8
normal Room Air PaO2 80-100
the 4 is smaller than the 5 and it means that of whats getting through 4/5ths is actually getting the oxygen
118
Explain what this means!!
Shunt
normal V/Q is 4/5 or 0.8
with a shunt the ventilation is lowered and perfusion remains good. think of it as if u had 0 ventilation and still good perfusion
0/5=0
(that is the example he gave in class just know that with a shunt the V/Q= 0 (or less than 0.8)
so if the VQ mismatch decreases you have a shunt!!!
119
explain what this means
Dead space!!
this is because with dead space you have ventilation but the perfusion decreases. so as perfusion decreases you have an infinity (this is again what he states in class)
so if normal V/Q is 4/5=0.8 then deadspace had an infinity
ex V=4 and Q= 0.5
4 / 0.5 = 8
so if the VQ mismatch goes up you have deadspace i
120
with V/Q ventilation is closely matched to what?
perfusion
121
3 main causes of a shunt
physiologic shunt
hypoventilation
disease states
122
with spontaneous ventilation
what part of the lungs are already maximally distended from greater NEGATIVE pleural pressure?
what does this mean
Apex alveoli
less ability to expand and receive volume increases
123
with spontaneous ventilation
what part of the lungs get the greatest gas flow due to greater change in thoracic pressures?
the basal alveoli
due to the diaphragmatic downward movement
124
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with spontaneous ventilation
There is a greater ______ \_\_\_\_\_\_\_\_ in the apex during end expiration and small changes during inspiration
Negative pressure
think of it as everything is pulling it down (in a standing position) so a greater negative pressure
125
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in what zone (zone of west) is the primary normal ventilation occurs ( where there is the lease VQ mismatch)
zone 3
126
why does positive pressure ventilation cause VQ mismatch?
B/C we end up ventilating the wrong zone. during mechanincal vent we have greasted blood flow to the dependent areas and bases, but the greatest gas flow is to the bases.
127
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explain the 3 ZONES of WEST and what they mean
1. PA \> Pa \> PV =Alveoli pressure is greatest it is greater than arterial and venous pressures. these alveolies are hyperinflated
2. Pa \> PA \> PV = arterial pressure greatest
3. Pa \> PV \> PA = Pulmonary artery pressure greatest with the least pressure in the alveoli allowing easy gas exchange ( so there is nothing pushing it back, good arterial pressure, good flow, the lung ISN'T over inflated this is ideal)
128
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explain Zone 1
"1st draw a picture"
Alveolar pressure exceeds arterial exceeds venous
129
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explain Zone 2
"1st draw a picture"
Arterial pressure exceeds Alveolar exceeds venous
130
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explain Zone 3
"1st draw a picture"
Arterial pressure exceeds venous exceeds alveolar
in teh supine position its all zone 3
131
When in the supine position what zone are you using the most?
3
132
With mechanical ventilation the greatest blood flow is to where?
bases
133
with mechanical ventilation the greatest gas flow is to what part of the lungs
Apexes
134
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VQ is poorly matched in mechanically ventilated patients! why is this???
Positive pressure ventilation pushesgas into the apexes (path of least resistance), but blood perfuses primarily to the dependent parts of the lung
thank you gravity
135
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what is a problem with mechanical ventialation??
specifically r/t to the poorly ventilated alveoli (in the bases)
poorly ventilated alveoli are prone to atelectasis and collapse
136
whos law deals with partial pressures?
daltons law
137
Daltons law of partial pressures for
N2O 79%
O2 21 %
138
what is the vapor pressure of water at 370C
47 mmHg
139
What si alveolar partial pressure?
what is the alveolar partial pressure for PAO2
and PAN2O
you must subtract H2O, add for CO2 and account for O2 abs
PAO2 104mmHg
PAN2O 569 mmHg
140
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what is normal PAO2 use (or use of O2)
250 mL/min
141
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what is teh normal PACO2 delivery
200 mL/min
142
CO2 is how many times as diffusible as O2
20x's
143
O2 is how many more times as diffusable as N2O
2 x's
144
explain the last 2 cards on diffusion
even though the CO2 gradient is low it is more diffusable so that was you can still have diffusion with a low gradient
O2 diffusion due to large gradients.
CO2 difusses with small gradients
145
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what % of O2 is bound to hemoglobin?
97%
146
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what % of O2 is dissolved in plasma???
3%
| (remember 97% is bound to hgb)
147
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a single Hgb holds how many O2 molecules?
4
148
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1 Gram of Hgb will hold how much O2
1.34 mL of O2
149
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if you have a Hgb of 15 g/dl how much O2 is being carried? and how did you get this answers?
20 mL
1 g of Hgb holds 1.34 mL of O2
so 15 x 1.34 = 20 mL/O2
150
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what is the formula for oxygen content ???
what is the equation for oxygen deliver??
Content: (1.34 x Hgb x SaO2) + (0.003 x PaO2)
Delivery: CONTENT x Cardiac Output
151
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what is the normal Aveolar (A) to arterial (a) O2 Gradient
5-10 mmHg
152
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how do we calculate the O2 Difference
PAO2 - PaO2
153
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How do we Calculate the _ideal ALVEOLAR gas equation_?
(how do we determine what the PAO2 (A) is so we can calculate the (A-a) O2 difference?)
PAO2= FiO2 (PBP - PH20) -PaCO2 / RQ
FIO2= inspired O2 (.21)
PBP = Barometric pressure (760 mmHg)
PH2O= Water vapor (47 mmHg)
RQ = Respiratory Quotient (0.8)
154
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with the A-a O2 Difference what are good numbers
single digits
155
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with the Alveolar gas equation how do you calculate RQ
PaCO2 / PaO2
normal 0.8
under ventilation 0.7 usually
156
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caculate the A-a O2 gradient. What is the R? is it normal? would O2 help?
PaO2=54
PaCO2 =32
