Pulmonary Function Tests Flashcards
1
Q
TLC
A
Deep Inspiration: Hold 4-6 L
2
Q
VC (vital capacity)
A
•amount exhaled AFTER maximal inspiration
3
Q
FRC
A
functional residual capacity
Gas remaining after normal expiration
4
Q
What cannot be measured by simple spirometry?
A
TLC, FRC, RV
(total lung capacity, functional residual capacity, and residual volume)
5
Q
IRV
A
(inspiratory reserve volume)
Amt. inhaled above normal TV (60% TLC)
6
Q
ERV
A
expiratory reserve volume
expiration beyond normal TV (20% TLC)
7
Q
Lung Capcity = ____
What are the 3 different formulas?
A
Lung Capacity = The sum of 2+ volumes
Vital Capacity=IRV+TV+ERV
FRC=ERV+RV
•TLC= IRV+TV+ERV+RV
8
Q
Spirometry = ___
A
Measurement of the speed and the amount of air that can be exhaled and inhaled. There are two types: static (for lung volumes) and dynamic (for FEV1 and flow rate).
9
Q
The simplest test of lung function is __ and is measured by ___.
A
forced expiration
spirometry
10
Q
Body Plethysmography test
A
patient sits in an upright chamber (looks like telephone booth) with a spirometer attached which is used to determine the flow properties of the patient
11
Q
Cardiopulmonary stress test
A
used to evaluate dyspnea that is out of proportion to findings on static pulmonary tests (to differentiate between cardiac and pulmonary issues)
12
Q
Diffusing Capacity of Lung for Carbon Dioxide
A
to evaluate the presence of possible parenchymal lung disease
13
Q
When the value of the patients SaO2 is 90%, you would expect the PaO2 to be _____.
A
60 mm Hg
14
Q
The P50 is ______.
A
the partial pressure of O2 at which Hgb is 50% saturated
15
Q
When the SO2 = 90 what is the PO2 ?
A
60
16
Q
When the SO2 = 83 what is the PO2 ?
A
50
17
Q
When the SO2 = 70 what is the PO2 ?
A
40
18
Q
When the SO2 = 50 what is the PO2 ?
A
27
19
Q
Physiologic dead space (Vd) is the sum of ______
A
Anatomic + Alveolar Vd =Physiologic Vd
20
Q
Anatomic dead space is characterized by _____.
A
air confined to the conducting airways.
21
Q
Alveolar Dead Space = ____
A
•Alveoli that are ventilated but not perfused
22
Q
Apparatus Dead Space = ____
A
Vd added by equipment
23
Q
What is the normal value for anatomic dead space?
A
150 ml
24
Q
What is the normal value for physiologic dead space?
A
150 ml
Becomes larger under certain disease conditions
25
Which type of dead space penetrates the gas exchange region of the lung?
Physiologic dead space
Anatomic dead space DOES NOT penetrate gas exchange regions of the lung
26
What parts of the respiratory tract are involved with anatomic dead space?
Nose, pharynx, trachea, and bronchi
27
What parts of the respiratory tract are involved with physiologic dead space?
Nose, pharynx, trachea, bronchi, bronchioles, alveolar duct, alveolar sac, & alveoli,
28
Which type of dead space has clinical importance?
Physiologic!
29
Dead space definition
Blood supply =
Ventilation =
Dead space = volume of air which does not take part in gas exchange, as it remains in the conducting airways or reaches alveoli, which are not perfused
Blood supply = Poor
Ventilation = Normal
30
Shunt definition
Blood supply =
Ventilation =
A shunt is a pathological condition, which results when the alveoli of the lungs are perfused with blood as normal, but the ventilation fails to supply the perfused region.
Blood supply = normal
Ventilation = poor
31
What are the different types of shunts?
What are the causes of a shunt?
Types: Anatomic and Capillary
Causes: Pneumonia and pulmonary edema, tissue trauma, atelectasis, mucus plugging, pulmonary arteriovenous fistulas etc.
32
Examples of Phsyiologic Shunts
Bronchial circulation
Thebesian veins
33
Examples of Intrapulmonary Shunts
AV malformations
ARDS
34
Examples of extrapulmonary shunts
Congenital heart disease
ASD/PFO
VSD
35
Causes of dead space
cardiovascular shock, emphysema, pulmonary embolism
36
What is the normal FEV1/FVC ratio?
**4l/5L= 0.8 / 80%**
(FEV1 = forced exhale over 1 second. Usually that normal is 4L give or take. And then the forced vital capacity is how much they can blow out completely.)
37
What would the FEV1/FVC ratio be with restrictive disease?
**\> = 0.8 / 80%**
38
What would the FEV1/FVC ratio be with obstructive disease?
\< 0.8 / 80%
39
With an obstructive pattern, the TLC is \_\_\_
normal or increased
40
With an restrictive pattern, the TLC is \_\_\_
decreased
41
What is the simplest test of lung function?
forced expiration
measured by spirometry
42
What are the lung volumes that can be measured by spirometry?
tidal volume
inspiratory reserve volume
expriatory reserve volume
vital capacity
43
static lung volumes are AKA \_\_\_\_
absolute volumes
| (they are more complicated)
44
residual volume vs. FRC = \_\_\_
residual volume = volume remaining in the lung after **forced** **maximal** exhalation
FRC = volume of tgas in the lung after **normal** exhalation
CANNOT BE MEASURED BY SIMPLE SPIROMETRY
45
forced exhalation is considered ____ and recommended that it is ___ in duration
dynamic
6 seconds
46
With obstructive patterns, the expiration tends to end prematurely. Why?
early airway closure brought about by increased smooth muscle tone or the loss of radial traction
radial traction is what helps keep our alveoli open
radial traction lost in pts with emphysema
47
With restrictive patterns, inspiration is limited by \_\_\_
the reduced compliance of either the lung (fibrotic) or chest wall, or weakness of your inspiratory muscles
48
intrapleural pressure is \_\_
theoretically always negative during inspiration
49
Helium is \_\_\_\_
virtually insoluble in blood
50
Measuring FRC with Helium Testing
after a few breaths, the helium concentrations should become the same (equilibrium).
The amount of helium that is present before and after the equilibriation phase is measured.
The helium is DILUTED by the functional residual capcity. The FRC is measured by the concentration of helium.
Not the best choice for obstructive disorders, but a good choice for normal lung function or restrictive.
51
Nitrogen Washout Method
We have 80% nitrogen concentration in our lungs, we wash it out with our oxygen.
patient breathes into a container, that volume is measured and is how we measure the patient's FRC with this test
52
Plethysmography (telephone booth) correlates with which gas law
Boyle's! P1V1 = P2V2
Christ that was a terrifying throwback to Berstein
53
The damage that is done with most pulmonary diseases like COPD will show up in the ____ airways.
smallest
54
A spirogram gives us what information?
the different lung volumes over time in seconds
55
Flow volume loop displays our \_\_\_
air flow
displayed in liters per second
as it relates to lung volume in liters during your maximal inspiration from a complete exhalation as well as during a maximum expiration from a complete inspiration
56
How are flow volume loops helpful?
Helpful in evaluation of airflow limitation on inspiration and on expiration
can help delineate on whether the pathology of a problem is intrathroacic or extrathoracic (see Connie's slide #15 for visual)
57
With upper airway problems, what will be mostly affected?
inspiratory flow
58
With the FVC, we look at **percent of predicted value** which is dependent on \_\_\_\_.
What is the normal value
patient's demographics (age, sex, race, height)
when we think about normal, the threshold is **80-120% of predicted value** given the patient's demographics (Connie said to remember this)
59
Why would your total lung capacity be increased with obstructive airway disease?
Air trapping!
Air trapping increases the total lung volume
60
Examples of obstructive lung disease
Asthma, COPD (emphysema, bronchitis), bronchiolitis/bronchiectasis
61
Examples of restrictive diseases
Interstitial lung disease – Neuromuscular weakness
Pleural disease – chest wall deformities - obesity
62
FVC values
**80 – 120% =Normal**
70 – 79% = Mild reduction
50 – 69% = Moderate reduction
**\< 50% = Severe reduction**
63
FEV1 values
\> 75% Normal
60 – 75% Mild obstruction
50 – 59% Moderate obstruction
\< 49% severe obstruction, \< 25 add 5%, \> 60 subtract 5%
64
FEF25-75
\> 79% Normal
60 – 79% Mild obstruction
40 – 59% Moderate obstruction
\< 40% Severe obstruction
65
TLC values
\> 79% Normal
70 – 79% Mild restriction
60 – 69% Moderate restriction
\< 60% Severe restriction
66
What values would be supportive of an asthma diagnosis for spirometry?
Improvement in volumes by 15% after an albuterol treatment
67
DLCO = ?
diffusing capacity of lungs for carb monoxide
68
Isolated reduction of DLCO raises possibility of \_\_\_\_\_.
pulmonary vascular disease
69
What would DLCO look like for restrictive disease?
(diffusion capacity)
Low diffusion capacity= Intrinsic disease (parenchymal lung disease, or increased thickness of tissue like fibrosis)
Normal diffusion capacity= Extraparenchymal causes of restriction (obesity, NM disease, chest wall limitations)
70
What would DLCO look like for obstructive disease?
(diffusion capcaity)
Low = emphysema (due to decreased surface area)
Normal = asthma
71
What is the normal PaO2 for arterial ABG
Some causes of hypoxia
Normal = 90-95 mmHg
* Alveolar hypoventilation
* Diffusion impairment
* Shunt
* Ventilation-perfusion inequality
* Reduced FiO2
72
The bronchial circulation sends blood to the ___ whereas the Thebesian veins send blood to the \_\_\_\_.
I DONT UNDERSTAND THE SIGNIFICANCE OF THIS IF ANYONE WANTS TO HELP A SISTER OUT
left atrium
left ventricle
73
Physiologic shunts are a mechanism of ___ to \_\_\_.
ventilation to perfusion mismatch
74
General facts about V/Q mismatch
* Ventilation \> perfusion at apex of lung
* Perfusion \> ventilation at base of lung
* HOWEVER, Both ventilation and perfusion are greater at base than they are at the apex
* Ventilation is estimated at 4 L
* Perfusion is estimated at 5L (consider this your cardiac output)
* Mismatch of 0.8
* Therefore arterial oxygen is 80 – 100 mmHg
* It's normal to have an alveolar to arterial oxygen difference
75
Oxygen Carrying Capacity
Based off of Henry's Law (Hgb X 1.34)
Blood is composed in two phases: plasma and red blood cells. The fracrtional volume of blood occupied by the RBCs is called the Hematoctrit. Value is normally 40% in women and 45% in men.
Oxygen is carried in blood in two forms. 98% attached to Hgb and 2% in dissolved plasma.
76
Partial pressure of oxygen in your arterial tree
(this is the formula Connie gave)
PaO2 = 760 -47 (0.21)
| (not sure I got this one right)
77
What is the normal oxygen consumption?
3.5 mL/kg/min
(with a 70kg patient, it would be approximately 250 ml/min)
\*she said to know this one
78
CO2 elevation and decreased pH cause what to the erythrocyte?
cause the erythrocyte to release the oxygen
(this comes from the oxyhemoglobin dissociate curve)
79
Deoxygenated Hemoglobin is going to be able to carry more \_\_\_
CO2
80
The Bohr effect describes \_\_\_
changes in Hgb oxygen affinity that arises from changes in the hydrogen concentration
81
A rightward shift in the curve would \_\_\_
increase the P50 and lowers the Hemoglobin's affinity for oxygen thus displacing the oxygen from the Hgb and releasing it to the tissues
82
A leftward shift in the curve would \_\_\_
decreases the P50 and increases Hgb's affinity for oxygen thus reducing its availability to the tissues
83
Causes of Hypoventilation
* Depression of respiratory centers (Drugs)
* Diseases of the medulla
* SCI
* Neuromuscular disorders (Guillain-Barre – ALS – Duchenne – MG)
* Thoracic abnormalities
* Upper airway obstruction
84
Causes of Diffusion Impairments
* Sarcoidosis
* asbestosis
* Pulmonary fibrosis
* Connective tissue disease
* Scleroderma – SLE – Wegener’s
85
If Dead space increases, \_\_\_.
minute ventilation (RR and/or Vt) must increase
86
What is pulmonary ventilation? How is it measured?
The total gas flow (including dead space gas volume)
The total volume of gas per/min inspired and expired = L/min
87
Alveolar Ventilation
* Amount of air that reaches the gas exchange areas.
* Vt (tidal volume) - anatomic dead space x RR
* A change in either RR or Vt will change alveolar ventilation
* Impairment in alveolar ventilation will increase the retention of CO2
* An increase in Vt is more effective to increase alveolar ventilation
88
Pearls of hypoventilation and hypercarbia
* Hypoventilation can cause hypercarbia and hypoxemia
* Supplemental oxygen can easily reverse hypoxemia, however it does nothing to reverse hypercarbia
* Hypercarbia can go undetected in the patient breathing supplemental oxygen
