1
Q
What are Static Lung Volumes?
A
Lung volumes measured during periods without air flow
These volumes provide important information about lung function.
2
Q
Define Functional Residual Capacity (FRC).
A
Volume of gas remaining in the lungs at the end-expiratory level
Typical value = 2400 mL or 2.4 L.
3
Q
How is Functional Residual Capacity (FRC) measured?
A
With a spirometer and a recording device
Reported in liters or milliliters, corrected to BTPS.
4
Q
What is the typical value of Functional Residual Capacity (FRC)?
A
2400 mL or 2.4 L
This value can vary based on lung health.
5
Q
How does FRC change with restrictive lung disease?
A
Decreased
Indicates reduced lung volume.
6
Q
How does FRC change with obstructive lung disease?
A
Increased
Due to air trapping.
7
Q
What is the formula for FRC?
A
FRC = ERV + RV or FRC = TLC - IC
These equations help in calculating lung volumes.
8
Q
Define Residual Volume (RV).
A
Volume of gas in the lungs at the end of maximum expiration
Typical value = 1200 mL or 1.2 L.
9
Q
How is Residual Volume (RV) measured?
A
With a spirometer and recording device
Reported in liters or milliliters, corrected to BTPS.
10
Q
What is the typical value of Residual Volume (RV)?
A
1200 mL or 1.2 L
This value can indicate lung health.
11
Q
How does RV change with restrictive lung disease?
A
Decreased
Indicates reduced lung volume.
12
Q
How does RV change with obstructive lung disease?
A
Increased
Reflects air trapping in the lungs.
13
Q
What is the formula for RV?
A
RV = FRC - ERV or RV = TLC - VC
These equations help in calculating lung volumes.
14
Q
Define Total Lung Capacity (TLC).
A
Volume of gas in the lungs following a maximum inspiration
Typical value = 6000 mL or 6.0 L.
15
Q
How is Total Lung Capacity (TLC) measured?
A
With a spirometer and recording device
Reported in liters or milliliters, corrected to BTPS.
16
Q
What is the typical value of Total Lung Capacity (TLC)?
A
6000 mL or 6.0 L
This value can indicate lung health.
17
Q
How does TLC change with restrictive lung disease?
A
Decreased
Indicates reduced lung volume.
18
Q
How does TLC change with obstructive lung disease?
A
Increased
Reflects air trapping in the lungs.
19
Q
What is the formula for TLC?
A
TLC = IRV + V + ERV + RV or TLC = IC + FRC or TLC = VC + RV
These equations help in calculating lung volumes.
20
Q
What is the typical vital capacity (VC) value?
A
4800 mL
Vital capacity is the maximum amount of air a person can exhale after a maximum inhalation.
21
Q
What is the typical residual volume (RV) value?
A
1200 mL
Residual volume is the amount of air remaining in the lungs after a forced exhalation.
22
Q
What is the typical functional residual capacity (FRC) value?
A
2400 mL
Functional residual capacity is the volume of air remaining in the lungs after a normal exhalation.
23
Q
What is the typical thoracic gas volume (VT) value?
A
2400 mL
Thoracic gas volume is the total volume of gas in the thoracic cavity.
24
Q
What is the typical total lung capacity (TLC) value?
A
6000 mL
Total lung capacity is the maximum amount of air the lungs can hold.
25
What does an **RV/TLC ratio** of 20% indicate?
20%
## Footnote
This ratio helps assess lung function and can indicate the presence of lung disease.
26
Decreased lung volumes indicate **what type of disease**?
Restrictive disease
## Footnote
Examples include pulmonary fibrosis and pneumonia.
27
Increased lung volumes, specifically **FRC, RV, TLC, VT**, indicate what type of disease?
Obstructive disease with air trapping
## Footnote
Examples include COPD and emphysema.
28
Name the methods used to measure **static lung volumes**.
* Helium dilution technique
* Nitrogen washout
* Body plethysmography
* Radiological estimation
## Footnote
These methods help assess lung volumes accurately.
29
What is the typical **vital capacity (VC)** value?
4800 mL
## Footnote
Vital capacity is the maximum amount of air a person can exhale after a maximum inhalation.
30
What is the typical **residual volume (RV)** value?
1200 mL
## Footnote
Residual volume is the amount of air remaining in the lungs after a forced exhalation.
31
What is the typical **functional residual capacity (FRC)** value?
2400 mL
## Footnote
Functional residual capacity is the volume of air remaining in the lungs after a normal exhalation.
32
What is the typical **thoracic gas volume (VT)** value?
2400 mL
## Footnote
Thoracic gas volume is the total volume of gas in the thoracic cavity.
33
What is the typical **total lung capacity (TLC)** value?
6000 mL
## Footnote
Total lung capacity is the maximum amount of air the lungs can hold.
34
What does an **RV/TLC ratio** of 20% indicate?
20%
## Footnote
This ratio helps assess lung function and can indicate the presence of lung disease.
35
Decreased lung volumes indicate **what type of disease**?
Restrictive disease
## Footnote
Examples include pulmonary fibrosis and pneumonia.
36
Increased lung volumes, specifically **FRC, RV, TLC, VT**, indicate what type of disease?
Obstructive disease with air trapping
## Footnote
Examples include COPD and emphysema.
37
Name the methods used to measure **static lung volumes**.
* Helium dilution technique
* Nitrogen washout
* Body plethysmography
* Radiological estimation
## Footnote
These methods help assess lung volumes accurately.
38
What method uses **helium** in a closed system to measure **FRC**?
Helium Dilution
## Footnote
This method involves rebreathing a known concentration of helium mixed with room air.
39
During the **helium dilution** test, what concentration of helium is typically used?
10%
## Footnote
The patient rebreathes this concentration mixed with room air.
40
What is the purpose of the **helium analyzer** in the helium dilution method?
To measure initial and final helium concentrations
## Footnote
These values are used to calculate the patient's FRC.
41
What indicates the **end of the test** in the helium dilution method?
Helium concentration changes by less than 0.02% over a 30 second interval
## Footnote
The maximum duration for the test is 10 minutes.
42
What should be maintained by adding small amounts of **oxygen** during the helium dilution test?
A consistent baseline
## Footnote
Oxygen may be added manually or automatically to the system.
43
How is **RV** calculated in the helium dilution method?
FRC - ERV
## Footnote
ERV is obtained from the basic spirometry (VC) measurement.
44
What is the formula for calculating **TLC** in the helium dilution method?
RV + VC = TLC
## Footnote
This calculation is part of the lung volume assessment.
45
What type of system does the helium dilution method utilize?
Closed system
## Footnote
It requires a CO2 absorber and desiccant in the circuit.
46
What must be subtracted from the **FRC** to account for helium absorbed by the blood?
A small volume
## Footnote
Additionally, the dead space volume of the breathing valve must also be subtracted.
47
What is the measurement condition for the helium dilution test?
Measured at ATPS; corrected to BTPS
## Footnote
This ensures accurate lung volume calculations.
48
How long should you wait before repeating the **helium dilution** procedure?
At least 5 minutes
## Footnote
This allows for clearance of helium from the lungs and the circuit.
49
What method uses **helium** in a closed system to measure **FRC**?
Helium Dilution
## Footnote
This method involves rebreathing a known concentration of helium mixed with room air.
50
During the **helium dilution** test, what concentration of helium is typically used?
10%
## Footnote
The patient rebreathes this concentration mixed with room air.
51
What is the purpose of the **helium analyzer** in the helium dilution method?
To measure initial and final helium concentrations
## Footnote
These values are used to calculate the patient's FRC.
52
What indicates the **end of the test** in the helium dilution method?
Helium concentration changes by less than 0.02% over a 30 second interval
## Footnote
The maximum duration for the test is 10 minutes.
53
What should be maintained by adding small amounts of **oxygen** during the helium dilution test?
A consistent baseline
## Footnote
Oxygen may be added manually or automatically to the system.
54
How is **RV** calculated in the helium dilution method?
FRC - ERV
## Footnote
ERV is obtained from the basic spirometry (VC) measurement.
55
What is the formula for calculating **TLC** in the helium dilution method?
RV + VC = TLC
## Footnote
This calculation is part of the lung volume assessment.
56
What type of system does the helium dilution method utilize?
Closed system
## Footnote
It requires a CO2 absorber and desiccant in the circuit.
57
What must be subtracted from the **FRC** to account for helium absorbed by the blood?
A small volume
## Footnote
Additionally, the dead space volume of the breathing valve must also be subtracted.
58
What is the measurement condition for the helium dilution test?
Measured at ATPS; corrected to BTPS
## Footnote
This ensures accurate lung volume calculations.
59
How long should you wait before repeating the **helium dilution** procedure?
At least 5 minutes
## Footnote
This allows for clearance of helium from the lungs and the circuit.
60
What may cause **erroneously high measurements** in lung testing?
* Leaks (circuit, at the mouthpiece, no nose clips, etc.)
* Ruptured eardrum (tympanic membrane)
* 'Switch-in' occurred before end-expiration
* Failure of analyzers
## Footnote
These factors can lead to inaccurate lung function test results.
61
What should be consistent during lung testing to ensure accurate **ERV measurement**?
Patient's breathing volume (V)
## Footnote
Irregular breathing can lead to under or overestimation of the ERV.
62
What indicates a **leak** during lung testing?
Failure to reach equilibrium
## Footnote
A leak can compromise the accuracy of lung function measurements.
63
What does an increase in the patient's **breathing pattern** indicate?
Exhausted CO₂ absorber
## Footnote
This requires replacement of the CO₂ absorber to ensure accurate measurements.
64
What should be done if the **cylinder pressure** is low at the start of the test?
Replace the cylinder
## Footnote
A starting pressure of 50 psi indicates the need for a new cylinder.
65
What is the approximate volume loss when **saturated expired air** passes through soda lime and silica gel?
5%
## Footnote
This loss should be considered when interpreting lung function test results.
66
What symptoms may indicate **hypoxemia** during lung testing?
* Dizziness
* Visual changes (dimming of lights)
## Footnote
The technologist should check the gas concentration mixture if these symptoms occur.
67
What effect does an **air leak** have on measured volumes?
Higher measured volumes
## Footnote
Air leaks can lead to falsely elevated lung function test results.
68
What should be checked if **slow equilibration times** occur in subjects with normal lung function?
Blower speed
## Footnote
Slow equilibration may indicate issues with the testing equipment.
69
What confirms that no **leaks** are present before testing begins?
Flat baseline
## Footnote
A flat baseline indicates proper setup and functioning of the testing equipment.
70
What should multiple measurements of **FRC** be within?
10%
## Footnote
Consistency in measurements is crucial for accurate lung function assessment.
71
What should be reported as the average of multiple **acceptable measurements**?
FRC
## Footnote
This ensures reliability in the results obtained from lung function tests.
72
What will moderate or severe **obstruction** result in regarding measurements?
Erroneously low measurements
## Footnote
Obstruction can significantly affect lung volume measurements.
73
What do **FRC, TLC, RV** being below LLN indicate?
Restrictive disorder
## Footnote
This finding suggests limitations in lung expansion.
74
What do **FRC, TLC, RV** being above ULN indicate?
Hyperinflation disorder
## Footnote
This condition reflects an abnormal increase in lung volumes.
75
What does a **RV/TLC ratio** greater than ULN indicate?
Air trapping
## Footnote
This finding is associated with obstructive lung diseases.
76
What may cause **erroneously high measurements** in lung testing?
* Leaks (circuit, at the mouthpiece, no nose clips, etc.)
* Ruptured eardrum (tympanic membrane)
* 'Switch-in' occurred before end-expiration
* Failure of analyzers
## Footnote
These factors can lead to inaccurate lung function test results.
77
What should be consistent during lung testing to ensure accurate **ERV measurement**?
Patient's breathing volume (V)
## Footnote
Irregular breathing can lead to under or overestimation of the ERV.
78
What indicates a **leak** during lung testing?
Failure to reach equilibrium
## Footnote
A leak can compromise the accuracy of lung function measurements.
79
What does an increase in the patient's **breathing pattern** indicate?
Exhausted CO₂ absorber
## Footnote
This requires replacement of the CO₂ absorber to ensure accurate measurements.
80
What should be done if the **cylinder pressure** is low at the start of the test?
Replace the cylinder
## Footnote
A starting pressure of 50 psi indicates the need for a new cylinder.
81
What is the approximate volume loss when **saturated expired air** passes through soda lime and silica gel?
5%
## Footnote
This loss should be considered when interpreting lung function test results.
82
What symptoms may indicate **hypoxemia** during lung testing?
* Dizziness
* Visual changes (dimming of lights)
## Footnote
The technologist should check the gas concentration mixture if these symptoms occur.
83
What effect does an **air leak** have on measured volumes?
Higher measured volumes
## Footnote
Air leaks can lead to falsely elevated lung function test results.
84
What should be checked if **slow equilibration times** occur in subjects with normal lung function?
Blower speed
## Footnote
Slow equilibration may indicate issues with the testing equipment.
85
What confirms that no **leaks** are present before testing begins?
Flat baseline
## Footnote
A flat baseline indicates proper setup and functioning of the testing equipment.
86
What should multiple measurements of **FRC** be within?
10%
## Footnote
Consistency in measurements is crucial for accurate lung function assessment.
87
What should be reported as the average of multiple **acceptable measurements**?
FRC
## Footnote
This ensures reliability in the results obtained from lung function tests.
88
What will moderate or severe **obstruction** result in regarding measurements?
Erroneously low measurements
## Footnote
Obstruction can significantly affect lung volume measurements.
89
What do **FRC, TLC, RV** being below LLN indicate?
Restrictive disorder
## Footnote
This finding suggests limitations in lung expansion.
90
What do **FRC, TLC, RV** being above ULN indicate?
Hyperinflation disorder
## Footnote
This condition reflects an abnormal increase in lung volumes.
91
What does a **RV/TLC ratio** greater than ULN indicate?
Air trapping
## Footnote
This finding is associated with obstructive lung diseases.
92
What is the **second method** to measure FRC in lung testing?
Replacing nitrogen in the lungs with oxygen
## Footnote
This method involves patient breathing 100% oxygen until nitrogen concentration falls below 1.5%.
93
During the **nitrogen washout** technique, how long should a patient with normal lung function take to washout?
3-4 minutes or less
## Footnote
Document patients who do not washout completely even after 7 minutes, indicating possible obstructive lung disease.
94
What should be documented if a patient does not washout completely after 7 minutes?
Obstructive lung disease (emphysema)
## Footnote
This documentation is crucial for assessing lung function.
95
When should the **switch-in** occur during the nitrogen washout test?
At the end of a normal expiration
## Footnote
This timing is important for accurate measurement.
96
How are the exhaled gases collected during the nitrogen washout test?
In a spirometer or bag
## Footnote
The final %N2 is used to calculate the FRC.
97
How are **RV** and **TLC** calculated in the nitrogen washout technique?
As with the helium dilution technique
## Footnote
Both methods provide insights into lung volumes.
98
What allows for **breath-by-breath analysis** in nitrogen washout testing?
Using a rapid nitrogen analyzer
## Footnote
This technology enhances the precision of measurements.
99
What type of method is used in nitrogen washout testing?
Open-circuit method
## Footnote
This method does not require a CO2 absorber since no rebreathing occurs.
100
What is the correction for measurements taken during nitrogen washout?
Measured at ATPS corrected to BTPS
## Footnote
This ensures accuracy in lung volume measurements.
101
How long should a patient breathe room air between repeated tests?
15 minutes
## Footnote
This interval helps to reset lung function before retesting.
102
What is the acceptable range for multiple FRC measurements?
Within 10% of each other
## Footnote
Consistency in measurements is key for reliable results.
103
What should be reported after multiple acceptable measurements of FRC?
The average of multiple measurements
## Footnote
This provides a more accurate representation of lung function.
104
What indicates a **restrictive disorder** in lung testing?
FRC, TLC, RV below the lower limit of normal (LLN)
## Footnote
This finding suggests reduced lung capacity.
105
What indicates a **hyperinflation disorder** in lung testing?
FRC, TLC, RV above the upper limit of normal (ULN)
## Footnote
This finding suggests excessive air in the lungs.
106
What does an **RV/TLC ratio** greater than ULN indicate?
Air trapping
## Footnote
This condition is often associated with obstructive lung diseases.
107
What is the **second method** to measure FRC in lung testing?
Replacing nitrogen in the lungs with oxygen
## Footnote
This method involves patient breathing 100% oxygen until nitrogen concentration falls below 1.5%.
108
During the **nitrogen washout** technique, how long should a patient with normal lung function take to washout?
3-4 minutes or less
## Footnote
Document patients who do not washout completely even after 7 minutes, indicating possible obstructive lung disease.
109
What should be documented if a patient does not washout completely after 7 minutes?
Obstructive lung disease (emphysema)
## Footnote
This documentation is crucial for assessing lung function.
110
When should the **switch-in** occur during the nitrogen washout test?
At the end of a normal expiration
## Footnote
This timing is important for accurate measurement.
111
How are the exhaled gases collected during the nitrogen washout test?
In a spirometer or bag
## Footnote
The final %N2 is used to calculate the FRC.
112
How are **RV** and **TLC** calculated in the nitrogen washout technique?
As with the helium dilution technique
## Footnote
Both methods provide insights into lung volumes.
113
What allows for **breath-by-breath analysis** in nitrogen washout testing?
Using a rapid nitrogen analyzer
## Footnote
This technology enhances the precision of measurements.
114
What type of method is used in nitrogen washout testing?
Open-circuit method
## Footnote
This method does not require a CO2 absorber since no rebreathing occurs.
115
What is the correction for measurements taken during nitrogen washout?
Measured at ATPS corrected to BTPS
## Footnote
This ensures accuracy in lung volume measurements.
116
How long should a patient breathe room air between repeated tests?
15 minutes
## Footnote
This interval helps to reset lung function before retesting.
117
What is the acceptable range for multiple FRC measurements?
Within 10% of each other
## Footnote
Consistency in measurements is key for reliable results.
118
What should be reported after multiple acceptable measurements of FRC?
The average of multiple measurements
## Footnote
This provides a more accurate representation of lung function.
119
What indicates a **restrictive disorder** in lung testing?
FRC, TLC, RV below the lower limit of normal (LLN)
## Footnote
This finding suggests reduced lung capacity.
120
What indicates a **hyperinflation disorder** in lung testing?
FRC, TLC, RV above the upper limit of normal (ULN)
## Footnote
This finding suggests excessive air in the lungs.
121
What does an **RV/TLC ratio** greater than ULN indicate?
Air trapping
## Footnote
This condition is often associated with obstructive lung diseases.
122
What does it indicate if the **%N** does not drop after several minutes during lung testing?
There is air leaking into the system
## Footnote
Room air contains 79% nitrogen.
123
When should you **replace the oxygen tank** during lung testing?
If the pressure is 50 psig or less
## Footnote
Maintaining proper oxygen levels is crucial for accurate testing.
124
What should be logged during lung testing?
* % N
* % N2
* Volume (Liters)
## Footnote
These logs help in diagnosing and troubleshooting issues.
125
What is a potential cause of **analyzer failure** during lung testing?
Moisture
## Footnote
Moisture can interfere with accurate readings.
126
What does a **N2 leak in the system** indicate during lung testing?
Potential issues with the testing setup
## Footnote
This can affect the accuracy of the test results.
127
What condition is indicated by the term **Obstructive (COPD)** in lung testing?
Chronic Obstructive Pulmonary Disease
## Footnote
This condition affects airflow and is a common diagnosis in lung function tests.
128
What does **Body Plethysmography** measure?
* FRC
* Thoracic Gas Volume (Vra)
* RV
* TLC
* (RV/TLC) X 100
## Footnote
Body Plethysmography is a method that measures static lung volumes.
129
What is **Thoracic Gas Volume (Vra)**?
The volume of gas contained in the thorax measured at end-expiration
## Footnote
This includes measurement of air trapped in the thorax not in communication with airways.
130
What is the formula for calculating the **RV/TLC ratio**?
(RV/TLC) X 100
## Footnote
This ratio is calculated by dividing residual volume by total lung capacity and multiplying by 100 to get a percentage.
131
What is the significance of **airways resistance** in lung testing?
It is a measure of the resistance to airflow in the airways
## Footnote
See Section III. Pulmonary Mechanics for more details.
132
List the steps for the **Technique for VTG**.
* Place patient in body box
* Adjust mouthpiece for a tight seal
* Close door for stable temperature
* Begin normal quiet breathing
* At end exhalation, close shutter
* Patient 'pants' at 30-60 bpm
* Measure pressures with transducers
## Footnote
These steps ensure accurate measurement of lung volumes.
133
What does **P mouth** equal when there is no airflow?
P alveolar
## Footnote
This indicates that the pressure at the mouth is equal to alveolar pressure.
134
What does **P box** represent in lung testing?
VTa
## Footnote
This pressure measurement is equal to the volume of gas in the thorax.
135
What law is used to calculate **thoracic gas volume**?
Boyle's Law
## Footnote
Boyle's Law relates the pressure and volume of a gas.
136
On the oscilloscope, **mouth pressure** (alveolar pressure) is plotted on which axis?
Vertical axis
## Footnote
This allows for the visualization of pressure changes during lung testing.
137
What is plotted on the **horizontal axis** of the oscilloscope?
Box pressure (volume change)
## Footnote
This represents the changes in lung volume during testing.
138
If the volume changed but the **alveolar pressure** did not, what could be the issue?
Mouth pressure transducer line not connected
## Footnote
This indicates a potential setup error in the testing procedure.
139
If the volume did not change but the **alveolar pressure** was moving, what might be wrong?
Box pressure transducer is disconnected or not working
## Footnote
This suggests a malfunction in the measurement system.
140
What does the assessment of lung function measure that is excluded from **FRC measurement**?
Gases that are trapped
## Footnote
This is important for accurate lung volume assessments.
141
In a patient with **normal lung function**, how should FRC measurements compare regardless of the method used?
Similar
## Footnote
Consistency in measurements indicates normal lung function.
142
In patients with **emphysema**, how does the Via compare to FRC measured by helium dilution and nitrogen washout?
Higher
## Footnote
This reflects the changes in lung mechanics associated with emphysema.
143
What is required for accurate lung testing by the **technologist**?
Careful instruction
## Footnote
Proper guidance is essential for reliable test results.
144
What should be the angle of the **pressure-volume loop**?
45 degrees
## Footnote
This angle is indicative of normal lung mechanics.
145
What does a flattened **pressure-volume curve** displaced downward indicate?
Restrictive lung disease, such as pulmonary fibrosis
## Footnote
This suggests limitations in lung expansion.
146
How many acceptable tests should be conducted for FRC measurement?
A minimum of three
## Footnote
Tests must be within 5% of each other for reliability.
147
What should be reported from the three acceptable tests?
Average FRC
## Footnote
This provides a more accurate representation of lung function.
148
What indicates **restrictive lung disease** in terms of FRC, TLC, RV?
Less than LLN
## Footnote
LLN stands for lower limit of normal.
149
What indicates **hyperinflation** in terms of FRC, TLC, RV?
Greater than ULN
## Footnote
ULN stands for upper limit of normal.
150
What does an RV/TLC ratio greater than **ULN** indicate?
Air trapping
## Footnote
This reflects abnormal lung mechanics.
151
What should a **shallow-breathing maneuver** have?
Closed loop with no artifact or thermal drift
## Footnote
This ensures accurate measurement during the test.
152
What law is used to calculate **thoracic gas volume**?
Boyle's Law
## Footnote
Boyle's Law relates the pressure and volume of a gas.
153
On the oscilloscope, **mouth pressure** (alveolar pressure) is plotted on which axis?
Vertical axis
## Footnote
This allows for the visualization of pressure changes during lung testing.
154
What is plotted on the **horizontal axis** of the oscilloscope?
Box pressure (volume change)
## Footnote
This represents the changes in lung volume during testing.
155
If the volume changed but the **alveolar pressure** did not, what could be the issue?
Mouth pressure transducer line not connected
## Footnote
This indicates a potential setup error in the testing procedure.
156
If the volume did not change but the **alveolar pressure** was moving, what might be wrong?
Box pressure transducer is disconnected or not working
## Footnote
This suggests a malfunction in the measurement system.
157
What does the assessment of lung function measure that is excluded from **FRC measurement**?
Gases that are trapped
## Footnote
This is important for accurate lung volume assessments.
158
In a patient with **normal lung function**, how should FRC measurements compare regardless of the method used?
Similar
## Footnote
Consistency in measurements indicates normal lung function.
159
In patients with **emphysema**, how does the Via compare to FRC measured by helium dilution and nitrogen washout?
Higher
## Footnote
This reflects the changes in lung mechanics associated with emphysema.
160
What is required for accurate lung testing by the **technologist**?
Careful instruction
## Footnote
Proper guidance is essential for reliable test results.
161
What should be the angle of the **pressure-volume loop**?
45 degrees
## Footnote
This angle is indicative of normal lung mechanics.
162
What does a flattened **pressure-volume curve** displaced downward indicate?
Restrictive lung disease, such as pulmonary fibrosis
## Footnote
This suggests limitations in lung expansion.
163
How many acceptable tests should be conducted for FRC measurement?
A minimum of three
## Footnote
Tests must be within 5% of each other for reliability.
164
What should be reported from the three acceptable tests?
Average FRC
## Footnote
This provides a more accurate representation of lung function.
165
What indicates **restrictive lung disease** in terms of FRC, TLC, RV?
Less than LLN
## Footnote
LLN stands for lower limit of normal.
166
What indicates **hyperinflation** in terms of FRC, TLC, RV?
Greater than ULN
## Footnote
ULN stands for upper limit of normal.
167
What does an RV/TLC ratio greater than **ULN** indicate?
Air trapping
## Footnote
This reflects abnormal lung mechanics.
168
What should a **shallow-breathing maneuver** have?
Closed loop with no artifact or thermal drift
## Footnote
This ensures accurate measurement during the test.
169
What is the **technique** used for radiological estimation of total lung capacity?
* Chest X-rays taken at total lung capacity from PA and lateral views
* Standard points marked on the image
* Measurements and geometric formulas used to calculate static lung volumes
## Footnote
This method provides a way to estimate lung volumes without direct measurement techniques.
170
True or false: Radiologic measurements of lung volumes are less accurate than body box measurements.
FALSE
## Footnote
Radiologic measurements are similar in accuracy to body box measurements.
171
In patients with **obstructive lung disease**, how do TLC, RV, and FRC values measured by radiologic methods compare to gas techniques?
Higher values than those measured by gas techniques
## Footnote
This indicates that radiologic methods may provide more accurate measurements in patients with air trapping.
172
In a patient with **normal lung function**, how should the results from radiologic methods compare to other methods?
Similar results
## Footnote
This suggests that radiologic methods are reliable for patients with normal lung function.
173
Radiological estimation of total lung capacity is useful in patients who are unable to perform other tests, such as those with _______.
tracheostomy or severe obstructive lung disease
## Footnote
This method provides an alternative for patients who cannot undergo standard lung function tests.
174
Diseases or conditions in which air is replaced with fluid or solid, such as pneumonia or lung tumors, will result in a _______ than actual thoracic gas volume measurement.
lower
## Footnote
This indicates that certain conditions can affect the accuracy of lung volume measurements.
175
What is the purpose of **Bronchoprovocation Challenge Testing**?
To detect airway hyperreactivity using a provocative agent or activity
## Footnote
Agents include methacholine, mannitol, hyperventilation, or exercise.
176
What are the two types of **Bronchial provocation testing**?
* Direct testing (methacholine or histamine)
* Indirect testing (exercise or voluntary hyperventilation)
## Footnote
Direct testing involves administering a specific agent, while indirect testing involves activities that may provoke a response.
177
Patients should avoid any activity that may induce **bronchospasm** such as __________.
Exposure to irritants, exercise work
## Footnote
Avoiding these activities is crucial before undergoing airway responsiveness testing.
178
List the medications that should be withheld prior to **Airway Responsiveness Testing**.
* Short-acting B-2 agonist (SABA)
* Long-acting B-2 agonist (LABA)
* Ultra Long-acting Anticholinergics
* Short-acting Muscarinic Antagonist (SAMA)
* Long-acting Muscarinic Antagonist (LAMA)
* Standard theophylline preparations
* Sustained-action theophylline preparations
* Cromolyn Sodium (Indirect Testing Only)
* Antihistamines (Indirect Testing Only)
* Corticosteroids (Indirect Testing Only)
* Leukotriene modifiers (Indirect Testing Only)
* Caffeine-containing drinks (Indirect Testing Only)
## Footnote
Withholding these medications is necessary to ensure accurate test results.
179
How long before testing should a patient withhold **Short-acting B-2 agonist (SABA)**?
6-8 hours
## Footnote
Example: albuterol.
180
How long before testing should a patient withhold **Long-acting B-2 agonist (LABA)**?
36-48 hours
## Footnote
Examples: salmeterol (Servant), formoterol (Foradil), arformoterol (Brovana), indacaterol.
181
What is the time to withhold **Cromolyn Sodium** before testing?
12-16 hours
## Footnote
This medication is only relevant for indirect testing.
182
True or false: **Corticosteroids** should be withheld for indirect testing only.
TRUE
## Footnote
This includes both inhaled and oral corticosteroids.
183
What is the time to withhold **theophylline preparations** before testing?
12-24 hours
## Footnote
Examples include Theolair and Theo-Dur.
184
How long before testing should a patient withhold **Antihistamines**?
48 hours
## Footnote
Examples include Benadryl, Zyrtec, Allegra, Claritin.
185
Fill in the blank: **Caffeine-containing drinks** should be withheld for _______ before testing.
6 hours
## Footnote
Examples include cola and coffee.
186
What is the **provocative concentration** (PC20%) in the methacholine challenge test?
The dosage of methacholine required for a positive test
## Footnote
A positive test is indicated by a 20% drop in FEV1.
187
What indicates a **positive test** in the methacholine challenge?
* 20% drop in FEV1
* Decrease of 35% or more in Gaw
## Footnote
These criteria help determine airway hyperreactivity.
188
List the **contraindications** for methacholine testing.
* Upper or lower respiratory infection
* Unable to perform baseline FEV1 maneuver > 60% of predicted
* Recent MI or stroke (past 3 months)
* Uncontrolled hypertension
* Recent eye surgery
* Risk of increased ICP
* Aortic aneurysm
## Footnote
These conditions may pose risks during the test.
189
True or false: Methacholine can be administered via nebulizer for the **1-minute tidal breathing method**.
TRUE
## Footnote
This method is preferred as it does not require a deep breath.
190
In the **5-Breath Dosimeter Test**, what is the first step?
Calibrate and prepare equipment
## Footnote
Proper calibration ensures accurate dosing and measurement.
191
What should be confirmed before starting the methacholine challenge test?
Compliance with pretest instructions
## Footnote
Ensures the validity of the test results.
192
What is the **preferred method** for administering methacholine?
1-minute tidal breathing method
## Footnote
This method is easier for patients as it does not require deep breaths.
193
What is the purpose of administering a **SABA** after the methacholine challenge?
To assess reversibility of airway obstruction
## Footnote
This helps determine if the airway response is reversible.
194
Fill in the blank: The **5-Breath Dosimeter Test** involves inhaling five breaths of nebulized normal saline as a _______.
control
## Footnote
This establishes a baseline before administering methacholine.
195
What is measured after each dose of methacholine during the challenge?
FEV1
## Footnote
This measurement helps determine the airway response to methacholine.
196
What is the **provocative concentration** (PC20%) in the methacholine challenge test?
The dosage of methacholine required for a positive test
## Footnote
A positive test is indicated by a 20% drop in FEV1.
197
What indicates a **positive test** in the methacholine challenge?
* 20% drop in FEV1
* Decrease of 35% or more in Gaw
## Footnote
These criteria help determine airway hyperreactivity.
198
List the **contraindications** for methacholine testing.
* Upper or lower respiratory infection
* Unable to perform baseline FEV1 maneuver > 60% of predicted
* Recent MI or stroke (past 3 months)
* Uncontrolled hypertension
* Recent eye surgery
* Risk of increased ICP
* Aortic aneurysm
## Footnote
These conditions may pose risks during the test.
199
True or false: Methacholine can be administered via nebulizer for the **1-minute tidal breathing method**.
TRUE
## Footnote
This method is preferred as it does not require a deep breath.
200
In the **5-Breath Dosimeter Test**, what is the first step?
Calibrate and prepare equipment
## Footnote
Proper calibration ensures accurate dosing and measurement.
201
What should be confirmed before starting the methacholine challenge test?
Compliance with pretest instructions
## Footnote
Ensures the validity of the test results.
202
What is the **preferred method** for administering methacholine?
1-minute tidal breathing method
## Footnote
This method is easier for patients as it does not require deep breaths.
203
What is the purpose of administering a **SABA** after the methacholine challenge?
To assess reversibility of airway obstruction
## Footnote
This helps determine if the airway response is reversible.
204
Fill in the blank: The **5-Breath Dosimeter Test** involves inhaling five breaths of nebulized normal saline as a _______.
control
## Footnote
This establishes a baseline before administering methacholine.
205
What is measured after each dose of methacholine during the challenge?
FEV1
## Footnote
This measurement helps determine the airway response to methacholine.
206
What is the **PC 20%** for the following test results?
2.8 L
## Footnote
Calculated as: (20% of 3.5 L = 0.7 L) and (3.5 - 0.7 = 2.8 L)
207
The percent change in **FEV** is determined by which formula?
% change = (Control value - Response value) X 100 / Control value
## Footnote
This formula calculates the percentage drop in FEV after administering methacholine.
208
What was the **% drop in FEV** for the patient after 0.60 mg/mL of methacholine was given?
11% drop
## Footnote
Calculated as: (3.5 - 3.1) = 0.4; (0.4 / 3.5) X 100 = 11%
209
What is the **initial dosage** of Methacoline in the preparation for testing?
100 mg (Dry Powder)
## Footnote
This is the starting amount used for both dosing schedules.
210
In the **doubling dosage** schedule, what is the concentration of the first dilution of Methacoline?
16.0 mg/mL
## Footnote
This is the highest concentration used in the doubling dosage schedule.
211
List the **concentrations** used in the **doubling dosage** schedule of Methacoline.
* 16.0 mg/mL
* 8.0 mg/mL
* 4.0 mg/mL
* 2.0 mg/mL
* 1.0 mg/mL
* 0.5 mg/mL
* 0.25 mg/mL
* 0.125 mg/mL
* 0.625 mg/mL
## Footnote
These concentrations are prepared by diluting the previous concentration.
212
In the **quadrupling dosage** schedule, what is the concentration of the first dilution of Methacoline?
16.0 mg/mL
## Footnote
This is the same as the first dilution in the doubling dosage schedule.
213
What is the **diluent** used in the preparation of Methacoline?
0.9% NaCL
## Footnote
This saline solution is used for diluting the dry-powder Methacoline.
214
How much **saline** is added to dry-powder Methacoline for each schedule?
6.25 mL
## Footnote
This amount is added before making subsequent dilutions.
215
In the **doubling dosage** schedule, what is the volume of saline added to each subsequent dilution?
3 mL or 9 mL
## Footnote
The choice between 3 mL or 9 mL depends on the specific dilution step.
216
In the **quadrupling dosage** schedule, what are the concentrations used?
* 16.0 mg/mL
* 4.0 mg/mL
* 1.0 mg/mL
* 0.25 mg/mL
## Footnote
These concentrations are prepared similarly to the doubling dosage but with fewer steps.
217
Fill in the blank: For each schedule, _______ mL of saline is added to dry-powder Methacoline.
6.25
## Footnote
This is the initial dilution step for both dosing schedules.
218
What does **exercise challenge testing** assess?
Airway hyperreactivity when heat and moisture are lost from upper airways during vigorous exercise
## Footnote
This testing is crucial for identifying exercise-induced bronchospasm (EIB).
219
What equipment is used in **exercise challenge testing**?
* Bicycle
* Treadmill
## Footnote
These are used to create workloads that increase the heart rate to 85% of the predicted maximum.
220
How long should the heart rate be maintained at 85% of the predicted maximum during **exercise challenge testing**?
4 - 6 minutes
## Footnote
This duration is essential for accurate assessment of airway response.
221
What is the target minute ventilation during **exercise challenge testing**?
40% - 60% of predicted MVV (FEV, X 40)
## Footnote
This calculation helps in determining the appropriate ventilation level for the test.
222
What patient monitoring is required during **exercise challenge testing**?
* Electrocardiogram (ECG)
* Blood pressure
* Pulse oximetry
## Footnote
Monitoring these parameters ensures patient safety during the test.
223
What is measured immediately after exercise in **exercise challenge testing**?
FEV1
## Footnote
Spirometry is performed to assess lung function post-exercise.
224
How often is spirometry repeated after exercise in **exercise challenge testing**?
Every 5 minutes
## Footnote
This continues until the FEV1 reaches its lowest level and then returns to normal.
225
What decrease in FEV1 is considered a **positive test** in exercise challenge testing?
10 - 15% decrease
## Footnote
This indicates significant airway hyperreactivity.
226
What should be done if the patient complains of **dyspnea** after exercising?
Perform an FVC maneuver
## Footnote
This helps assess the extent of airway obstruction.
227
What can be given to reverse bronchospasm after a 10 - 15% decrease in FEV1?
Aerosolized bronchodilators
## Footnote
This treatment helps alleviate bronchospasm symptoms.
228
What does **Eucapnic Voluntary Hyperventilation (EVH)** assess?
Airway hyperreactivity by having the patient breathe at a high rate of ventilation
## Footnote
This method provokes bronchospasm through increased ventilation.
229
What gas mixture is used during **Eucapnic Voluntary Hyperventilation (EVH)**?
5% CO2, 21% O2, balance nitrogen
## Footnote
This mixture is inhaled for 4 - 6 minutes to provoke bronchospasm.
230
How often is spirometry performed during **Eucapnic Voluntary Hyperventilation (EVH)**?
Immediately and then every 5 minutes for the next 30 minutes
## Footnote
This timing allows for monitoring of FEV1 changes.
231
What decrease in FEV1 indicates a **positive test** in EVH?
10 - 15% decrease
## Footnote
This signifies significant airway hyperreactivity.
232
What indicates a **negative test** in EVH?
FEV1 does not decrease within 30 minutes of increased ventilation
## Footnote
This suggests no significant airway hyperreactivity.
233
What should be done at the end of the **Eucapnic Voluntary Hyperventilation (EVH)** test?
Reverse bronchospasm
## Footnote
This is important for patient safety and comfort.
234
What does **exercise challenge testing** assess?
Airway hyperreactivity when heat and moisture are lost from upper airways during vigorous exercise
## Footnote
This testing is crucial for identifying exercise-induced bronchospasm (EIB).
235
What equipment is used in **exercise challenge testing**?
* Bicycle
* Treadmill
## Footnote
These are used to create workloads that increase the heart rate to 85% of the predicted maximum.
236
How long should the heart rate be maintained at 85% of the predicted maximum during **exercise challenge testing**?
4 - 6 minutes
## Footnote
This duration is essential for accurate assessment of airway response.
237
What is the target minute ventilation during **exercise challenge testing**?
40% - 60% of predicted MVV (FEV, X 40)
## Footnote
This calculation helps in determining the appropriate ventilation level for the test.
238
What patient monitoring is required during **exercise challenge testing**?
* Electrocardiogram (ECG)
* Blood pressure
* Pulse oximetry
## Footnote
Monitoring these parameters ensures patient safety during the test.
239
What is measured immediately after exercise in **exercise challenge testing**?
FEV1
## Footnote
Spirometry is performed to assess lung function post-exercise.
240
How often is spirometry repeated after exercise in **exercise challenge testing**?
Every 5 minutes
## Footnote
This continues until the FEV1 reaches its lowest level and then returns to normal.
241
What decrease in FEV1 is considered a **positive test** in exercise challenge testing?
10 - 15% decrease
## Footnote
This indicates significant airway hyperreactivity.
242
What should be done if the patient complains of **dyspnea** after exercising?
Perform an FVC maneuver
## Footnote
This helps assess the extent of airway obstruction.
243
What can be given to reverse bronchospasm after a 10 - 15% decrease in FEV1?
Aerosolized bronchodilators
## Footnote
This treatment helps alleviate bronchospasm symptoms.
244
What does **Eucapnic Voluntary Hyperventilation (EVH)** assess?
Airway hyperreactivity by having the patient breathe at a high rate of ventilation
## Footnote
This method provokes bronchospasm through increased ventilation.
245
What gas mixture is used during **Eucapnic Voluntary Hyperventilation (EVH)**?
5% CO2, 21% O2, balance nitrogen
## Footnote
This mixture is inhaled for 4 - 6 minutes to provoke bronchospasm.
246
How often is spirometry performed during **Eucapnic Voluntary Hyperventilation (EVH)**?
Immediately and then every 5 minutes for the next 30 minutes
## Footnote
This timing allows for monitoring of FEV1 changes.
247
What decrease in FEV1 indicates a **positive test** in EVH?
10 - 15% decrease
## Footnote
This signifies significant airway hyperreactivity.
248
What indicates a **negative test** in EVH?
FEV1 does not decrease within 30 minutes of increased ventilation
## Footnote
This suggests no significant airway hyperreactivity.
249
What should be done at the end of the **Eucapnic Voluntary Hyperventilation (EVH)** test?
Reverse bronchospasm
## Footnote
This is important for patient safety and comfort.
250
What is the **Mannitol Challenge Test** used for?
To monitor asthma disease activity and assess anti-inflammatory therapy
## Footnote
Mannitol stimulates the release of mediators acting on bronchial smooth muscle.
251
What age group is appropriate for the **Mannitol Challenge Test**?
> 6 years old
## Footnote
Patients should not exhibit asthmatic signs or symptoms.
252
What is the required **inspiratory flow** during the Mannitol Challenge Test?
Approximately 60 L/min
## Footnote
This flow provides good delivery and minimizes coughing.
253
What is recorded after a **60 second delay** during the Mannitol Challenge Test?
The highest FEV1
## Footnote
FEV1 is the forced expiratory volume in one second.
254
What indicates a positive result in the Mannitol Challenge Test?
* 15% drop in FEV1 (PD15%)
* Incremental decrease in FEV1 of > 10%
## Footnote
This is measured between consecutive mannitol doses.
255
What is administered at the end of the **Mannitol Challenge Test**?
An aerosolized SABA
## Footnote
SABA stands for short-acting beta-2 agonist.
256
How long should a **short-acting B-2 agonist (SABA)** be withheld before testing?
6 - 8 hours
## Footnote
Examples include albuterol and levalbuterol.
257
How long should a **long-acting B-2 agonist (LABA)** be withheld before testing?
36 hours
## Footnote
Examples include salmeterol and formoterol.
258
What is the recommended time to withhold **theophylline preparations** before testing?
12-24 hours
## Footnote
Standard preparations include Theophylline and Theolair®.
259
How long should **inhaled corticosteroids** be withheld before testing?
6 hours
## Footnote
Examples include beclamethasone and fluticasone.
260
What should patients avoid for at least **6 hours** prior to the Mannitol Challenge Test?
Smoking
## Footnote
Smoking can affect test results.
261
What should patients avoid for **4 hours** prior to the Mannitol Challenge Test?
Vigorous exercise
## Footnote
Exercise can increase airway hyperreactivity.
262
How long should testing be delayed after a **viral infection**?
Up to 3 weeks
## Footnote
Viral infections can increase airway hyperreactivity.
263
What type of gloves should not be worn during **mannitol testing**?
Rubber/latex gloves
## Footnote
They can increase static and affect inhaler function.
264
What is the **definition** of Airways Resistance (R)?
Difference in pressure between the mouth (atmospheric) and the alveoli, related to gas flow at the mouth
## Footnote
This definition is crucial for understanding pulmonary mechanics.
265
What is the formula for calculating **Airways Resistance (R)**?
Atmospheric (mouth) Pressure - Alveolar Pressure / Flow
## Footnote
This formula helps quantify the resistance in the airways.
266
How is Airways Resistance (R) **measured**?
* Body plethysmography
* Pneumotach
* Mouth pressure
* Box pressure
* Shutter
## Footnote
These tools are essential for accurate measurement of airway resistance.
267
In what units is Airways Resistance (R) recorded?
cm H,O/L/second
## Footnote
This unit is standard for measuring airflow resistance.
268
What is the typical value range for **Airways Resistance (R)**?
0.6 - 2.4 cm H,O/L/sec
## Footnote
Understanding typical values is important for diagnosing respiratory conditions.
269
What does Raw represent in the context of **Airways Resistance (R)**?
The ratio of alveolar pressure (P) to Airflow (V)
## Footnote
This ratio is critical for assessing lung function.
270
What is the recommended technique for measuring **Airways Resistance (R)**?
* Patient 'pants gently' at 1.5 - 2.5 breaths/second
* Shutter open for measurements at FRC
## Footnote
This technique allows for accurate assessment of airflow and pressure.
271
What type of curve is created on the screen during the measurement of **Airways Resistance (R)**?
An S-shaped curve plotting flow (V) against box pressure (Pbox)
## Footnote
This visual representation aids in understanding the relationship between flow and pressure.
272
What is the **definition** of **Airways Resistance (R)**?
Difference in pressure between the mouth (atmospheric) and the alveoli, related to gas flow at the mouth
## Footnote
This concept is crucial for understanding pulmonary mechanics.
273
What is the **formula** for calculating **Airways Resistance (R)**?
Atmospheric (mouth) Pressure - Alveolar Pressure / Flow
## Footnote
This formula helps quantify the resistance encountered during breathing.
274
How is **Airways Resistance (R)** measured?
* Body plethysmography
* Pneumotach
* Mouth pressure
* Box pressure
* Shutter
## Footnote
These tools are essential for accurate pulmonary function testing.
275
In what units is **Airways Resistance (R)** recorded?
cm H₂O/L/second
## Footnote
This unit is commonly used in respiratory physiology.
276
What equipment is used to measure **pressures** and **flow** in lung testing?
* Transducers for pressure measurement
* Pneumotach for flow measurement
## Footnote
These instruments are vital for obtaining precise data during pulmonary assessments.
277
What is the **typical value** range for **Airways Resistance (R)**?
0.6 - 2.4 cm H₂O/L/sec
## Footnote
Values outside this range may indicate respiratory issues.
278
What does the technique for measuring **Airways Resistance (R)** involve?
* Ratio of alveolar pressure (P) to Airflow (V)
* Patient 'pants gently' at 1.5 - 2.5 breaths/second
* Measurements made at FRC
## Footnote
This technique allows for accurate assessment of lung mechanics.
279
What does the maneuver during the measurement of **Airways Resistance (R)** create on the screen?
An S-shaped curve plotting flow (V) against box pressure (Pbox)
## Footnote
This visual representation aids in analyzing respiratory function.
280
What is the purpose of the **mouth shutter** in lung testing?
To momentarily close at the end of a normal expiration
## Footnote
This action produces a second curve that plots mouth pressure against box pressure.
281
In lung testing, what does the **plethysmograph** measure?
It measures mouth pressure and box pressure
## Footnote
These measurements are used to calculate the raw data from the curves produced.
282
What are the two types of pressure plotted in lung testing?
* Mouth Pressure
* Box Pressure
## Footnote
These pressures are essential for analyzing lung function.
283
Fill in the blank: The **raw data** in lung testing is calculated from the two curves produced by the _______.
plethysmograph
## Footnote
The plethysmograph provides critical data for lung function analysis.
284
Airways resistance in a normal adult is divided into which three categories?
* Nose, mouth, upper airway
* Trachea, bronchi
* Small airways
## Footnote
The distribution is approximately 50% for the nose, mouth, and upper airway, 30% for the trachea and bronchi, and 20% for small airways.
285
True or false: Raw changes significantly in patients with obstructive disease due to small airways.
FALSE
## Footnote
Small airways contribute only a small amount to total resistance, hence Raw changes very little.
286
What causes significant increases in Raw measurements?
* Large airway obstructions (e.g., tumors)
* Increased work of breathing
* Dyspnea on exertion
## Footnote
These factors are associated with large airway obstructions.
287
During an acute asthma attack, Raw may increase by how much?
Three-fold
## Footnote
This significant increase indicates worsening airway resistance.
288
Patients with advanced emphysema may demonstrate increased Raw due to involvement of which airways?
Large airways
## Footnote
This involvement contributes to increased airway resistance.
289
What is the utility of the test mentioned in the text?
Obtaining accurate information regarding airway condition in patients who cannot or will not give a good effort on other flow tests
## Footnote
This test is particularly useful for assessing airway conditions in challenging patient populations.
290
Some patients may be unable to perform which maneuver?
The panting maneuver
## Footnote
This limitation can affect the assessment of airway resistance.
291
What has the greatest effect on Raw, causing turbulent airflow?
Gas density
## Footnote
Changes in gas density can significantly impact airway resistance.
292
Airways resistance may also be reported per liter of lung volume, referred to as _______.
specific resistance or Saw
## Footnote
This measurement is expressed in cm H₂O/L.
293
What does **high inspiratory resistance** indicate?
High inspiratory and expiratory resistance caused by a fixed airway obstruction
## Footnote
This condition can significantly affect airflow during breathing.
294
What can be done to eliminate **artifact** during lung testing?
Have the patient use his hands to minimize jaw and cheek movement
## Footnote
This helps ensure accurate test results.
295
What does **gentle panting** not affect during lung testing?
The glottis
## Footnote
Gentle panting does not cause airway compression.
296
What does widening of the loop indicate in lung testing?
Increasing airways resistance or a slow respiratory rate
## Footnote
This can be observed in the graphical representation of airflow.
297
What is indicated by **overall increased resistance** typically seen with asthma?
Expiratory flow issues
## Footnote
This is a common characteristic of asthma-related lung function.
298
What does hysteresis in lung testing indicate?
Low panting frequency or large panting volume
## Footnote
Hysteresis can affect the accuracy of lung function measurements.
299
What is the definition of **Airway Conductance (Gaw)**?
Flow per unit of pressure change
## Footnote
Reported in L/sec/cm H,O; it is the reciprocal of Raw or 1 + Row or 1/Raw.
300
How is **Specific Conductance (SGaw)** measured?
Per liter of lung volume (L/sec/cm H,O/L)
## Footnote
SGaw = 1/Ra.
301
What is the normal value range for **Airway Conductance (Gaw)**?
0.42 - 1.67 L/sec/cm H,O
## Footnote
This value is used for assessing airway function.
302
True or false: **SGaw** is particularly helpful for determining the effectiveness of bronchodilator therapy in cooperative patients.
FALSE
## Footnote
SGaw is useful for uncooperative malingering patients.
303
What is the definition of **Compliance (C)**?
Volume change per unit of pressure change in liters/cm H,O or milliliters/cm H,O
## Footnote
Cir = compliance of the lungs and thorax; C = compliance of the lungs only; Cy = compliance of the thorax only.
304
What is one method to measure **compliance** in mechanically ventilated patients?
Recording the plateau pressure at different lung volumes
## Footnote
Another method involves intubating a patient and using positive pressure ventilation.
305
What is the procedure to measure **compliance** using a spirometer?
Patient breathes at tidal volume before and after weights are added to the spirometer
## Footnote
This method helps in assessing lung compliance.
306
How is **C** calculated from the pressure-volume curve?
From the slope of the pressure-volume curve over the segment from FRC to FRC + 0.5 L
## Footnote
Measurements are taken at points of zero flow.
307
At a patient's resting **FRC**, what is the esophageal balloon pressure approximately?
- 5 cm H,O
## Footnote
This measurement is important for assessing lung function.
308
What is recorded as the **maximum elastic recoil pressure**?
Most negative pressure at maximum lung volume (TLC)
## Footnote
This indicates the lung's ability to return to its resting state.
309
How is **static lung compliance** obtained?
By comparing the difference between esophageal and mouth pressure to absolute lung volume under static conditions
## Footnote
This is measured over the entire volume range available.
310
What is the formula for **static lung compliance** (C)?
Cst = change in lung volume / change in transpulmonary pressure
## Footnote
Measured over the straight portion of the volume-pressure curve between FRC and FRC + 0.5 L.
311
What are the **units** for static lung compliance?
L/cm H,O
## Footnote
This unit measures the change in lung volume per unit change in pressure.
312
What does the **Coefficient of Retraction (COR)** express?
Maximal static recoil pressure of the lung relative to lung volume (TLC)
## Footnote
It indicates how much pressure the lung can generate at total lung capacity.
313
What is the formula for the **Coefficient of Retraction**?
COR = Pst at TLC / TLC
## Footnote
This helps in understanding lung mechanics.
314
What are the **normal values** for static lung compliance?
0.2 L/cm H,O
## Footnote
This value indicates normal lung function.
315
What is the normal range for the **Coefficient of Retraction**?
4 - 8 cm H,O/L
## Footnote
This range reflects normal lung elasticity.
316
What is the normal range for **maximum static recoil pressure**?
24.4 - 34.5 cm H,O
## Footnote
This indicates the lung's ability to recoil after inflation.
317
True or false: **Lung compliance decreases** in patients with restrictive diseases.
TRUE
## Footnote
Conditions like fibrosis and pneumonia lead to decreased lung compliance.
318
True or false: **Lung compliance increases** in patients with emphysema.
TRUE
## Footnote
Emphysema causes loss of elasticity, leading to increased compliance.
319
In patients with **chest wall disease** or obesity, what happens to thoracic compliance?
Decreases
## Footnote
This affects the overall lung function.
320
What are measurements taken during airflow called?
**Dynamic compliance**
## Footnote
This differs from static compliance, which is measured without airflow.
321
Normal subjects have the same compliance at **static points** as they have at **dynamic points**. True or false?
TRUE
## Footnote
This indicates consistency in lung mechanics.
322
What does **Maximum Inspiratory Pressure (MIP)** measure?
Largest amount of inspiratory pressure against an occluded airway
## Footnote
MIP is a key indicator of respiratory muscle strength.
323
How is **MIP** measured?
* With a calibrated manometer
* Attached to a flanged mouthpiece and a three-way stopcock
## Footnote
The measurement is taken in cm H₂O.
324
What is a **typical value** for MIP?
-60 cm H₂O or greater
## Footnote
This value indicates normal inspiratory muscle strength.
325
List the **steps** in the technique for measuring MIP.
* Patient places flanged mouthpiece in mouth
* Nose clips are placed on the nose
* Patient expires maximally to residual volume
* Stopcock is rotated to close off air
* Patient inhales and maintains Pplat for 1.5 seconds
* Pressure is read from the manometer
* Small leak is provided to offset cheek muscle movement
* Perform at least 3 maneuvers
* Record the largest value from 3 acceptable maneuvers that vary <20%
## Footnote
Pediatric patients may require a mask with nose clips.
326
What does MIP assess?
Inspiratory muscle strength
## Footnote
It is crucial for evaluating respiratory function.
327
What conditions can lead to **decreased MIP**?
* Neuromuscular disease
* Diseases involving the diaphragm or other respiratory muscles (e.g., emphysema)
* Chest wall or spinal deformities
## Footnote
Notably, pulmonary fibrosis does not decrease MIP.
328
What is the **definition** of Maximum Expiratory Pressure (MEP)?
The highest positive pressure that can be generated during a forced expiration against an occluded airway
## Footnote
MEP is measured in cm H₂O.
329
What is the **typical value** range for Maximum Expiratory Pressure (MEP)?
80 - 100 cm H₂O
## Footnote
This value indicates normal respiratory function.
330
What is the **technique** for measuring Maximum Expiratory Pressure (MEP)?
* Patient inhales to total lung capacity
* Stopcock is closed
* Patient exhales maximally for 1.5 seconds
* Pressure recorded from manometer
* Minimum of 3 acceptable maneuvers
* Record largest of 3 maneuvers that vary less than 20%
## Footnote
The same equipment as MIP is used for MEP measurement.
331
What conditions can lead to **decreased** Maximum Expiratory Pressure (MEP)?
* Neuromuscular problems (generalized muscle weakness)
* Emphysema
* Chronic bronchitis
* Cystic fibrosis
* Inability to cough
## Footnote
These conditions affect respiratory muscle function and airway clearance.
332
What troubleshooting step should be taken if MEP values are **reversed**?
Do not report the values but review the calculations
## Footnote
MIP must always be a negative number and MEP must always be a positive number.
333
What is the purpose of the **Cough Peak Flow (CPF)** test?
To assess patient's ability to generate an effective cough
## Footnote
This test is important for evaluating respiratory function.
334
Describe the **technique** used for Cough Peak Flow (CPF).
* Patient inspires fully
* Coughs forcefully into a spirometer or peak flow meter
* Sitting position
* Mouthpiece or face mask can be used with or without a nose clip
## Footnote
This technique helps measure the peak expiratory flow during a cough.
335
What are the **normal values** for Cough Peak Flow (CPF)?
Between 110 L/min and 950 L/min
## Footnote
Normal values depend on age, height, and gender.
336
What is indicated if Cough Peak Flow (CPF) values are less than **270 L/min**?
May need coughing assistance
## Footnote
Low CPF values suggest impaired cough effectiveness.
337
How many efforts should be reported for Cough Peak Flow (CPF)?
The highest value of 3 to 5 efforts
## Footnote
This ensures accuracy in measuring peak flow.
338
What does **CO Diffusion Testing (Dico)** measure?
How well carbon monoxide (CO) can diffuse across the alveolar-capillary (A-C) membrane
## Footnote
Reported in mLCO/min/mmHg, STPD (0°C, 760 mmHg, dry).
339
What is the **normal value** for Dico?
25 mLCO/min/mmHg STPD
## Footnote
This value indicates the standard diffusion capacity for carbon monoxide.
340
Name a factor that affects **Dico** values.
* Hemoglobin (Hb) and Hematocrit (Hct)
* Alveolar PCO2
* Carboxyhemoglobin (COHb)
* Pulmonary capillary blood volume (Q)
* Body position
* Altitude
* Breath-holding time
* Wash-out volume
* Alveolar sampling technique
## Footnote
Each factor can either increase or decrease Dico values based on physiological changes.
341
True or false: An increase in **Carboxyhemoglobin (COHb)** will decrease Dico.
TRUE
## Footnote
A 1% increase in COHb will decrease Dico by 1% due to backpressure.
342
How does **body position** affect Dico values?
Supine position increases Dico due to increased capillary blood flow compared to sitting upright
## Footnote
This change in position can significantly influence the diffusion capacity.
343
What happens to Dico values at **increasing altitude**?
Dico values increase due to decreasing PO2
## Footnote
This is a physiological response to maintain adequate oxygenation.
344
What is the **wash-out volume** prior to collecting the alveolar sample?
Normally 1.0 L or less
## Footnote
This volume is discarded to ensure accurate measurement of alveolar gas.
345
What is the typical volume collected for **alveolar sampling**?
Normally 0.5 L - 1.0 L
## Footnote
This volume is used for analysis in Dico testing.
346
How do Dico values change during **exercise**?
Dico values will normally increase 2 - 3 times
## Footnote
This reflects the increased demand for gas exchange during physical activity.
347
In patients with **restrictive disease**, how do Dico values change?
Dico values decrease due to loss of lung volume
## Footnote
Conditions like pulmonary fibrosis and sarcoidosis exemplify restrictive lung diseases.
348
Which **obstructive lung disease** is known to reduce Dico values?
Emphysema
## Footnote
This reduction is due to loss of surface area, V/Q mismatch, and increased distance from the terminal bronchiole to the A-C membrane.
349
What does **CO Diffusion Testing (Dico)** measure?
How well carbon monoxide (CO) can diffuse across the alveolar-capillary (A-C) membrane
## Footnote
Reported in mLCO/min/mmHg, STPD (0°C, 760 mmHg, dry).
350
What is the **normal value** for Dico?
25 mLCO/min/mmHg STPD
## Footnote
This value indicates the standard diffusion capacity for carbon monoxide.
351
Name a factor that affects **Dico** values.
* Hemoglobin (Hb) and Hematocrit (Hct)
* Alveolar PCO2
* Carboxyhemoglobin (COHb)
* Pulmonary capillary blood volume (Q)
* Body position
* Altitude
* Breath-holding time
* Wash-out volume
* Alveolar sampling technique
## Footnote
Each factor can either increase or decrease Dico values based on physiological changes.
352
True or false: An increase in **Carboxyhemoglobin (COHb)** will decrease Dico.
TRUE
## Footnote
A 1% increase in COHb will decrease Dico by 1% due to backpressure.
353
How does **body position** affect Dico values?
Supine position increases Dico due to increased capillary blood flow compared to sitting upright
## Footnote
This change in position can significantly influence the diffusion capacity.
354
What happens to Dico values at **increasing altitude**?
Dico values increase due to decreasing PO2
## Footnote
This is a physiological response to maintain adequate oxygenation.
355
What is the **wash-out volume** prior to collecting the alveolar sample?
Normally 1.0 L or less
## Footnote
This volume is discarded to ensure accurate measurement of alveolar gas.
356
What is the typical volume collected for **alveolar sampling**?
Normally 0.5 L - 1.0 L
## Footnote
This volume is used for analysis in Dico testing.
357
How do Dico values change during **exercise**?
Dico values will normally increase 2 - 3 times
## Footnote
This reflects the increased demand for gas exchange during physical activity.
358
In patients with **restrictive disease**, how do Dico values change?
Dico values decrease due to loss of lung volume
## Footnote
Conditions like pulmonary fibrosis and sarcoidosis exemplify restrictive lung diseases.
359
Which **obstructive lung disease** is known to reduce Dico values?
Emphysema
## Footnote
This reduction is due to loss of surface area, V/Q mismatch, and increased distance from the terminal bronchiole to the A-C membrane.
360
What happens if a **tight seal** is not maintained during lung testing?
Air will be introduced into the sample, resulting in an increased Dico
## Footnote
This can lead to erroneous test results.
361
What are the requirements for **unidirectional valves** in lung testing?
* Low deadspace (< 100 mL)
* Low resistance to flow
* Easy to maintain
## Footnote
These features prevent increased resistance and leaks.
362
True or false: **Tracheal stenosis** affects the Duco SB.
FALSE
## Footnote
Tracheal stenosis is an upper airway obstruction that does not affect the Duco SB.
363
What effect does **polycythemia** have on Dico?
It will increase the Dico above 100% of predicted
## Footnote
This indicates an abnormal increase in red blood cells.
364
In the **Single Breath CO Diffusion (DLco SB)** test, what is the composition of the gas mixture inhaled by the patient?
* 0.3% CO
* 10% He
* 21% O
* Balance is N
## Footnote
This mixture is used to assess gas exchange in the lungs.
365
What should the **inspired volume** be during the DLco SB test?
It should be > 90% of the largest VC or > 85% of the largest VC AND VA within 200 ml or 5%
## Footnote
This ensures accurate measurement during testing.
366
What is the purpose of **helium** in the DLco SB test?
* Corrects for CO trapped in RV
* Serves as a carrier gas for CO to the alveolar level
## Footnote
Helium helps in accurate diffusion measurement.
367
During the DLco SB test, how long should the patient hold their breath?
10 seconds (8 - 12 seconds)
## Footnote
Breath hold should be relaxed against a closed glottis or closed valve.
368
What effect does excessive **positive pressure** (Valsalva) have during the DLco SB test?
It reduces capillary blood flow and gives a false low Dico
## Footnote
This can lead to inaccurate test results.
369
What effect does excessive **negative pressure** (Müller) have during the DLco SB test?
It increases capillary blood flow and gives a false high Dico
## Footnote
This can also lead to inaccurate test results.
370
What happens if a **tight seal** is not maintained during lung testing?
Air will be introduced into the sample, resulting in an increased Dico
## Footnote
This can lead to erroneous test results.
371
What are the requirements for **unidirectional valves** in lung testing?
* Low deadspace (< 100 mL)
* Low resistance to flow
* Easy to maintain
## Footnote
These features prevent increased resistance and leaks.
372
True or false: **Tracheal stenosis** affects the Duco SB.
FALSE
## Footnote
Tracheal stenosis is an upper airway obstruction that does not affect the Duco SB.
373
What effect does **polycythemia** have on Dico?
It will increase the Dico above 100% of predicted
## Footnote
This indicates an abnormal increase in red blood cells.
374
In the **Single Breath CO Diffusion (DLco SB)** test, what is the composition of the gas mixture inhaled by the patient?
* 0.3% CO
* 10% He
* 21% O
* Balance is N
## Footnote
This mixture is used to assess gas exchange in the lungs.
375
What should the **inspired volume** be during the DLco SB test?
It should be > 90% of the largest VC or > 85% of the largest VC AND VA within 200 ml or 5%
## Footnote
This ensures accurate measurement during testing.
376
What is the purpose of **helium** in the DLco SB test?
* Corrects for CO trapped in RV
* Serves as a carrier gas for CO to the alveolar level
## Footnote
Helium helps in accurate diffusion measurement.
377
During the DLco SB test, how long should the patient hold their breath?
10 seconds (8 - 12 seconds)
## Footnote
Breath hold should be relaxed against a closed glottis or closed valve.
378
What effect does excessive **positive pressure** (Valsalva) have during the DLco SB test?
It reduces capillary blood flow and gives a false low Dico
## Footnote
This can lead to inaccurate test results.
379
What effect does excessive **negative pressure** (Müller) have during the DLco SB test?
It increases capillary blood flow and gives a false high Dico
## Footnote
This can also lead to inaccurate test results.
380
What is the maximum duration for **rapid exhalation** during lung testing?
Less than 4 seconds
## Footnote
Total exhalation time should be less than 4 seconds.
381
What is the **washout volume** in lung testing?
750 to 1000 mL
## Footnote
The first portion of the exhaled sample is discarded, termed the washout volume.
382
What is collected after the washout volume during lung testing?
End-tidal or alveolar sample
## Footnote
The next 500 - 1000 mL is collected after the washout volume.
383
If the **FVC** is small (<2.0 L), what should the washout volume be decreased to?
500 mL
## Footnote
This adjustment is made if the FVC is small.
384
What data are collected to calculate the **Dico**?
* Initial and final CO (F,CO, F_CO)
* Initial and final He (F,He, F_He)
* Inspired and alveolar volume (V,, V)
* Breath-hold time (T)
## Footnote
These measurements are essential for calculating diffusion capacity.
385
What is the initial alveolar CO% in lung testing?
0.03%
## Footnote
This value represents room air concentration.
386
What is the most commonly used technique for measuring **diffusion capacity**?
Single breath technique
## Footnote
It is simple, fast, and easy to calculate.
387
How long should you wait between **repeated tests**?
Minimum of 4 minutes
## Footnote
This ensures accurate results between tests.
388
What should be reported as the average for lung testing?
Two or more acceptable tests
## Footnote
Results should be within 2 mL/min/mmHg.
389
What is the maximum number of tests allowed during one session?
Five
## Footnote
This limit is set for lung testing sessions.
390
In the **Steady State CO Diffusion** method, what concentration of CO is used?
0.1% - 0.2% CO
## Footnote
This mixture is breathed for 5 - 6 minutes to achieve a steady-state.
391
What is the purpose of the **steady-state procedure** in lung testing?
More appropriate for stress testing and patients with inspiratory obstruction
## Footnote
This method is beneficial for patients who have difficulty following instructions.
392
What is collected during the final 2 minutes of the steady-state procedure?
Exhaled gas in a neoprene balloon or Douglas bag
## Footnote
An ABG is also drawn during this time.
393
What data are measured to calculate the **Dico SS**?
* Inspired and expired CO (F,CO, F_CO)
* Inspired and expired N2 (FN2, FeN2)
* Exhaled volume (Ve)
* Exhaled CO2 (P_CO2)
* Arterial CO2 (PaCO2)
* Inspired and expired O2 (F_O2, FO2)
## Footnote
These measurements are essential for calculating diffusion capacity in the steady-state technique.
394
What is required for the calculation of **P_CO**?
PECO2 and Paco2
## Footnote
These values are necessary for accurate calculations.
395
What is the **End-Tidal CO Diffusion (Duco SS)** method?
Measures average end-tidal CO tension (PErCO) from breath-by-breath analysis with an infrared analyzer
## Footnote
Assumes end-tidal P,CO equals the P,CO used to calculate the D co.
396
What is the **Assumed V, CO Diffusion (Dico SS)** method?
Calculates F CO using a formula that assumes V, to be 1/mL per pound of body weight
## Footnote
The calculated F CO is used to derive the P,00 for the Doo Calculation.
397
What does the **Mixed Venous PCO, CO Diffusion (Dico SS)** method involve?
* Measures VCO using the same method as D co SS
* Estimates mixed venous CO, partial pressure (PVCO,) from an equilibration technique
## Footnote
This technique avoids the need to draw a blood sample.
398
What is the **Rebreathing CO Diffusion (Duco RB)** method?
* Uses a balloon reservoir filled with a mixture of 0.3% CO, 10% He, and air
* Patient exhales to RV, rebreathes from the balloon for 30-60 seconds
* Final concentrations of CO, He, and O, are recorded
## Footnote
This method is rarely used due to the need for considerable patient cooperation.
399
What is the process of **Intrabreath CO Diffusion (Pico B)**?
* Patient inhales a mixture of 0.3% CO, 0.3% CH, 21% O, and N
* Exhales slowly from TLC to RV
* Infrared analyzers measure CO and CH concentrations
## Footnote
Multiple estimates of Dico are made during exhalation; can be used during exercise testing.
400
What does **Dm** stand for in lung testing?
Membrane Diffusion Coefficient/Factor
## Footnote
Dm is used to assess the resistance caused by the A-C membrane.
401
How can the **resistance** caused by the A-C membrane be calculated?
By performing the co SB at two different levels of oxygen
## Footnote
This method helps in establishing the Hb reaction rate curve.
402
What is the significance of measuring the **ico** at two levels of oxygen?
It establishes the Hb reaction rate curve
## Footnote
This is important because oxygen competes with CO for binding sites on hemoglobin.
403
What does back extrapolation to a point of **zero O** identify?
The resistance caused by the A-C membrane
## Footnote
This technique is used to analyze the effects of the membrane on gas exchange.
