Exam 3 Flashcards
(140 cards)
1
Q
What is normal exhaled nitrogen concentration?
A
75-85%
2
Q
What is contained in the first part of exhalation during the Fowler’s test?
A
Should be 100% O2 & 0% nitrogen
3
Q
In the Fowler’s test, when does dead space measurement begin & end?
A
- Begins at start of expiration.
- Ends at midpoint of transitional phase
4
Q
What needs to be done before starting a Nitrogen washout test?
A
Check initial nitrogen content
5
Q
How long will a nitrogen washout test take in a healthy Pt?
A
3mins or less
6
Q
What results in an abnormal nitrogen washout test & why does it happen?
A
- It is considered abnormal if >7 mins.
- It is due to uneven distribution of inspired air
7
Q
What equipment is needed for a nitrogen washout test?
A
- Stopwatch
- Nitrogen meter
- 100% O2 source
- Pneumotachograph
8
Q
What is the concentration goal of the nitrogen washout test?
A
Get to a nitrogen ≤ 2.5%
9
Q
What do nitrogen spikes on the nitrogen washout test mean?
A
- Pt has poorly vented areas to start with.
- These get ventilated, then open up & let nitrogen out
10
Q
What does a Closing volume/capacity test look at?
A
- Looks at behavior of the tissue in the lungs
- Dead space
11
Q
Explain the steps of a closing volume/capacity test?
A
1) Expire to RV
2) Inspire 100% O2 to TLC
3) Exhale
12
Q
What is the total lung’s nitrogen concentration (%) on a healthy person before exhalation while performing a closing volume/capacity test?
A
1) Calculate N2 concentration in RV
2) PiN2 is 564 mmHg
3) 564 mmHg / 760 mmHg= 74.21%
4) 0.7421 x 1,500 mL= 1,113.15 mL/N2
5) 1,113.15 mL / 6,000 mL= 0.1855
6) Total lung N2 concentration is 18.55%
13
Q
Phase 1 of a Closing volume/capacity test should show?
A
Expired oxygen only as it coming from the dead space.
14
Q
What will the transitional phase of a Closing volume/capacity test should show?
A
Should start seeing expiration of N2
15
Q
Where is the volume coming from during phase 3 of Closed volume test?
A
Expired air from all parts of the lungs
16
Q
Phase 4 of a Closing volume/capacity test shows?
A
- A sharp upstroke of expired N2.
- Base of lung is collapsed.
- Expired N2 comes from top of lungs
17
Q
When do airways start closing during a closing volume test & what is the order?
A
- At end of phase 3 & beginning of phase 4.
- Areas right above the diaphragm start closing first then superior sections.
18
Q
At what point is expired N2 concentration equal from the entire lung?
A
During phase 3 of a closing volume test
19
Q
Where does the closing volume air come from?
A
From the upper parts of the lungs
20
Q
How is closing capacity calculated?
A
RV + closing volume
21
Q
What volumes/capacities increase w/ age & which decrease?
A
- Increase: RV, CC, FRC
- Decrease: ERV, IC, VC
22
Q
At what age is FRC equal to closing capacity?
A
At age 50ish
23
Q
What happens to the airway during forced expiration?
A
It widens
24
Q
How much VC should a healthy 20yo move in 1 sec?
A
About 80%
25
A healthy person can force expire at what rate?
10 L/sec
26
What happens during effort independence?
- It happens closer to RV.
- The small airways collapse d/t + pleural pressure. At that point air will only come out so fast, not matter how hard one pushes.
27
Someone with emphysema has a shorter or longer effort independence?
- Longer.
- They take longer to get the air out.
28
What will expiratory flow curve look like in someone with a restrictive disease?
It will be narrower than normal
29
Compared to normal, restrictive disease will result in a ___ FEF?
Lower
30
In someone with restrictive disease the TLC will be___ & the RV will be___?
Lower & lower
31
At RV, zone 3 & 4 will be ___% full & zone 1 will be ____% full?
- 20%
- 30%
32
At RV where is most of the nitrogen located?
In the upper zones
33
How is Ptp calculated?
Ptp = Alveolar pressure – pleural pressure
34
How is alveolar pressure calculated?
PA= pleural pressure + elastic recoil pressure
35
During forced expiration the diaphragm is relaxed or contracted?
It is relaxed
36
Which muscles contract during forced expiration?
- The internal intercostals
- accessory muscles
37
How can alveolar collapse be prevented in a non-intubated Pt?
- Have to restrict outflow, which leads to elevated internal alveolar pressures.
- Can do this with pursing the lips.
38
At RV the dependent pleural pressure is___ & the non-dependent pleural pressure is___?
+ 4.8
- 2.2
39
During passive expiration the pleural pressure is ___& the elastic recoil pressure is?
Negative & positive
40
How is elastic recoil pressure calculated?
Per= Alveolar pressure – pleural pressure
41
What are the expired PAO2 & PACO2?
- 100 mmHg
- 40 mmHg
42
What is the CO2 in the pulmonary vein & artery?
- Vein: 40 mmHg
- Artery: 45 mmHg
43
What is the PO2 in the pulmonary vein & artery?
- Vein: 100 mmHg
- Artery: 40 mmHg
44
How are wall tension & radius related?
- Inversely
- Decreased wall tension = increased radius
45
Where would a fixed obstruction be located & what is affected. What’s an example?
- Located anywhere in the lung.
- Affects peak inspiration & peak expiration rates.
- An example would be an ETT.
46
What is a variable extrathoracic obstruction, where is it located & an example & what respiratory cycle part is most affected?
- An obstruction during inspiration.
- It is located in the trachea or above (scar tissue or paralyzed vocal cords).
- Inspiration is greatly affected by narrowing of the airway.
- During expiration obstruction gets pushed out of the way.
47
In a variable extrathoracic obstruction the PAW is___ than Patm during inspiration & ___ during expiration?
Less & greater
48
In a variable intrathoracic obstruction the PAW is___ than Ppl during inspiration & ___ during expiration?
Greater & lesser
49
What is most likely affected in a variable intrathoracic obstruction?
Expiration & the very small airways
50
Emphysema would correlate to what kind of obstruction?
A variable intrathoracic affecting expiration
51
Why does inspiration start before EtCO2?
The EtCO2 sample line has a bit of lag.
52
Relate alveolar ventilation to PaCO2 & EtCO2?
Doubling alveolar ventilation will half PaCO2 & EtCO2
53
How do the carotid & aortic arch blood gas sensors work?
If PaCO2 increases sensors will send feedback to CV system to increase CO, which also leads to increased BP.
54
What is an easy way to lower a ventilated Pt’s BP?
Blow off some CO2
55
Inspired PO2 & CO2 are ____ & equilibrated PO2 & CO2 are____?
- 150 & 0 mmHg.
- 100 & 40 mmHg
56
Inhaling 350cc fresh air drops the PACO2 to about___?
36-37 mmHg
57
What prevents great CO2 swings?
Volume of FRC.
58
What is CO2’s Pp in the lungs at after normal inspiration?
1) FRC= 3L, PACO2= 40 mmHg
2) 40 mmHg/760 mmHg= 0.05263
3) 0.05263 x 3L= 0.157L
4) 0.157L = 157 mL/CO2
5) 0.157 L / 3.35 L= 0.047131
6) 0.047131 x 760 mmHg= 35.819 mmHg
7) 35.819 mmHg / 760 mmHg= 0.047
8) 0.047 x 3.35 L= 0.15788L
9) 0.15788L = 158 mL/CO2
59
What are some causes for low EtCO2?
- Low CO
- MI
- PE
- moisture in equipment
60
How much O2 does 1 dL contain in solution?
0.003 mL O2/mmHg PO2
61
How much O2 does 1 dL contain at a Pp of 100 mmHg solution?
0.3 mL O2
62
How much oxygen/dL is immediately available in a solution w/ a Pp of 80 mmHg?
80 x 0.003 mL O2/mmHg= 0.24 mL O2/dL
63
How much O2 does 1 dL drop off?
5 mL
64
What is normal Hgb for our class?
15 g/dL
65
How much O2 can each gram of Hgb carry?
1.34 mL O2
66
What is the max Hgb carrying capacity?
20.1 mL O2/dL
67
How does carbon monoxide affect the oxygen in the blood?
CO reduces the ability of Hgb to unload its oxygen
68
What 2 things does carbon monoxide do?
Binds to Hgb & prevents unloading of oxygen from Hgb
69
What is MET hemoglobin?
- Dysfunctional Hgb
- Does not like to carry O2.
- Makes up about 2% of Hgb
70
As PaO2 decreases Hgb ___ oxygen?
Unloads
71
What is the normal CvO2 in mL/dL at a PO2 of 40 mmHg?
15.2 mL/dL
72
Increased PCO2 will cause a ___ shift?
Right
73
An increase in pH will cause a ____ shift?
Left
74
What kind of shift will cause the Hgb to hold on to oxygen?
A left shift (alkalosis, low CO2, low 2,3-bpg, low temp)
75
What is 2,3-BPG? Spell it out?
- Byproduct of metabolism.
- 2,3-Biphosphoglyceric acid
76
If we had no Hgb at all, what would our tissue oxygen deficit be in mL/dL?
- Negative 4.7 mL O2/dL.
- Each dL of blood drops off 5 mL O2.
- Available dissolved O2 in solution is 0.3 mL O2/dL.
77
What two things does dissolved gasses rely on?
Its solubility & partial pressure
78
What is the venous Hgb saturation?
70-75% Venous PO2 is 40 mmHg
79
What is the Hgb saturation at a PO2 of 70 mmHg?
94.1% with 19.12 mL O2/dL
80
What kind of shift does fetal Hgb have & why?
Left shift d/t its higher affinity to oxygen
81
Relate PO2 & the oxyhemoglobin curve?
A right shift in the oxyhemoglobin curve will lead to a higher PO2
82
Where is myoglobin present?
In weight bearing skeletal muscles
83
What is the P50 value for arterial blood?
26.5 mmHg
84
What is the P50 value for venous blood?
~ 32-33 mmHg
85
What does the Bötzinger Complex do?
It controls respiratory rhythm, sigh and gasping
86
Where is the Apneustic center located & what does it do?
- Located in the lower PONS.
- Senses the environmental air & gradually increases firing rate of the inspiratory muscles
87
What inhibits the Apneustic center?
The Pneumotaxic center
88
What do the central chemoreceptors respond to?
H+, CO2 & pH (Do not respond to O2 level changes)
89
What is the primary driver for peripheral bodies?
CO2
90
How do chemoreceptors respond to increased CO2?
They increase firing rate
91
Aortic bodies use the___ nerve/s & carotid bodies use the ___ nerve/s?
- Vagus nerve
- Hering’s & Glossopharyngeal nerves
92
What is the length of a normal trachea?
11-13 cm & can extend another 2cm with extension
93
How long is the Right main stem?
About 2cm
94
The R bronchi has ___ segments & the Left bronchi has __ segments?
10 & 10 which fuses down to 8
95
What is all part of the nasopharynx (that we covered in lecture)?
- Pharyngeal tonsils
- Pharyngotympanic tube orifice
96
What are the 3 salivary glands from smallest to largest?
- Sublingual gland
- Submandibular gland
- Parotid gland
97
What enlarged structure can obstruct nasal air passage?
Enlarged pharyngeal tonsil (also called adenoid tonsil)
98
What enlarged structure can obstruct oral air passage?
Enlarged palatine tonsils
99
How many total tonsils do we have?
6
- 1 Pharyngeal tonsil
- 2 Tubal tonsils
- 2 Palatine tonsils
- 1 Lingual tonsil
100
What nerves innervate the upper airway?
- Trigeminal nerve
- Glossopharyngeal
- Vagus
101
How many branches does the Trigeminal nerve have & what are their names?
3
- Ophthalmic (V1)
- maxillary (V2)
- mandibular (V3)
102
The Glossopharyngeal nerve innervates what two structures in the upper airway?
Back of the tongue & nasopharynx
103
What is the source of the “ice cream headache”?
The Maxillary branch of the Trigeminal nerve. Also called Palatine nerve
104
What 3 airway structures are innervated by the Vagus nerve?
- Epiglottis
- Vallecula
- posterior/inferior throat incl. trachea
105
What 2 nerves innervate taste?
- Glossopharyngeal (9) back third of tongue
- Facial nerve (7) front 2/3 of tongue
106
What tongue nerves are somatic?
- Glossopharyngeal (9)
- Trigeminal/Submandibular (5v3)
107
Where does the Falx cerebri anchor to?
The Crista galli of the Ethmoid bone
108
What connects ethmoid bone to meninges?
The Crista galli
109
A nasal ET tube passes through the___ in between the___ & the___?
- Inferior meatus.
- Inferior concha & maxilla palatine process
110
The external carotid art. supplies the____ & the internal carotid art. supplies the___?
- Posterior septum
- Roof of the nose
111
What are the 3 large cartilages?
- Epiglottis
- thyroid cartilage
- cricoid cartilages
112
What is the pinch point in adults?
The vocal cords
113
What is the pinch point in children <10yrs of age?
The cricoid cartilage
114
The vocal cords attach anteriorly to the___ & posteriorly to the___?
- Thyroid cartilage
- Arytenoid cartilage
115
Which turbinates do not come of the ethmoid bone?
- The inferior concha/turbinates.
- They come off the maxilla
116
What is the pharyngotympatic tube?
An opening that helps with equilibrium & pressure of the middle & inner ears
117
A spirometer can be used to measure what volumes/capacities?
All except TLC, RV & FRC
118
How does a low CO affect PvO2?
A low CO results in a high extraction of O2 from the blood to supply tissue
119
What changes increase diffusion of a gas thru membrane according to Fick's law?
- Increased △P, area, solubility.
- Decreased distance & MW
120
How does breathing 100% O2 affect PaO2 with right to left shunts?
It has little effect on PaO2
121
How does strenuous exercise affect arterial alveolar capillaries & Hgb saturation?
Strenuous exercise causes a decrease in alveolar arterial end oxygen & flow is faster thru alveolar capillaries, so it takes longer to fully saturate = more gradual rise (Right shift).
122
How does the complete absence of Hgb, with normal lungs, affect PaO2
Without Hgb the PO2 would still be normal due to O2 dissolving in plasma
123
How does anemia affect CaO2 & O2 saturation?
Leads to lower CaO2 & O2 saturation is not affected
124
What does CO combined with Hgb form?
carboxyhemoglobin
125
Carboxyhemoglobin causes what kind of a shift & how does it affect the tissues?
Carboxyhemoglobin creates a Left shift & Hgb holds on tight to O2, decreasing O2 to tissues
126
What is the body's major response to PaCO2?
Chemo sensors in medulla. CO2 diffuses across BBB & is converted to H+ acting on chemo sensors.
127
The ____ center tells the ___ to limit inspiration time, which also leads to a decreased expiratory time & increased RR
Pneumotaxic & DRG
128
What controls the basic respiratory rhythm?
The DRG, located within the NTS
129
When does the VRG become active?
When greater than normal pulmonary ventilation is required
130
What is the purpose of chloride diffusing into venous RBC's?
To maintain electrical neutrality
131
Compare the volume & chloride of venous & arterial RBCs?
Venous RBCs have larger volume & more Cl- than arterial RBCs
132
How does decreased PaCO2 affect ventilation?
Decreased PaCO2 inhibits chemosensitive areas --> decreased ventilation until PaCO2 is normal.
133
How does does constrictive lung disease affect TLC, RV & MEF?
Reduces TLC, RV & max expiratory flow
134
What happens to ventilation when PaO2 falls to 60 mm Hg or less?
Ventilation doubles when PaO2 falls to 60 mmHg
135
How does atelectasis of 1 lung affect:
- V/Q ratio
- Resistance
- Blood flow
- PaO2
- CaO2
- O2 saturation
- V/Q ratio only changes minimally
- Increased resistance to blood flow + vasoconstriction d/t hypoxia
- blood flow shifting to other lung
- small decrease in PaO2, CaO2 & Sats.
136
Exhaled PO2 is greater of lower than PAO2
Greater
137
Exhaled PCO2 is greater or lesser than PACO2
Lesser
138
What muscles, besides the diaphragm are used for forced inspiration
External intercostal muscles
139
Peripheral chemoreceptors increase ventilation by what mechanisms?
1) decreased PO2
2) increased PCO2
3) Increased H+
4) decreased pH
140
What is the most important breathing drive in chronic hypercapnia?
The peripheral chemoreceptor hypoxic drive is more important
