Pulmonary Function Testing
CRT 7? = 5%
RRT 4?
Which of the following are purposes of assessing
pulmonary function?
I. Screen for pulmonary disease
II. Evaluate patients for surgical risk
III. Assess the progression of disease
IV.Assist in determining pulmonary disability
V. Modify the therapeutic approach to patient
care
A. I, III, and IV
B. III, IV, and V
C. I, II, III, IV, and V
D. II, IV, and V
Which of the following techniques are used to
measure RV?
I. Helium dilution
II. Body plethysmography
III. Nitrogen washout
IV.Flow-volume loops
A. II and IV
B. I, II, and III
C. I, II, III, and IV
D. I, III, and IV
600 ml
10% He
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
Helium Dilution
Closed Method
A known % of He is
diluted by the patient’s
FRC. The change in
the He% is used to
determine FRC


Nitrogen Washout, Open Method
The FRC is washed out of the lung by having the
patient inspire 100% O2 to replace the N2 from the
FRC. The amount of N2 removed is used to
calculate FRC
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
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Boyle’s Law to
TGV
Patient pants at FRC
while pressures and
volumes are obtained
Raw can be determined
by measuring changes
in pressure vs. flow




Plethysmography
Body Box
0.6 – 2.4 cmH2O/L/sec
Compliance can be
determined by
measuring the volume
change per unit
pressure change

60 – 100 mL/cmH2O
During a helium dilution test for FRC, you notice
that it takes 19 minutes for equilibration
between the gas concentrations in the
spirometer and the patient's lungs. Based on
this information, what can you conclude?
A.The patient has restrictive lung disease.
B.The spirometer is leaking helium.
C.The patient has obstructive lung disease.
D.Insufficient oxygen was added to the system.
What is the gas normally employed to measure
the diffusing capacity of the lung?
A.O2
B.CO
C.CO2
D.He
Gas Diffusion (DLCO)
Carbon monoxide diffusion capacity
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




Evaluates diffusion across the A-C membrane
Patient inhales a VC breath of gas containing a
known amount of CO.
Breath hold for 10 sec.
Exhaled gas is analyzed.
Normal 25 mLCO/min/mmHg
 emphysema, pulmonary fibrosis,
sarcoidosis, edema, O2 toxicity
On a patient undergoing testing in the pulmonary
function laboratory, you observe a "box–
shaped" flow–volume loop with equal
reductions in inspiratory and expiratory flows.
What does this most likely indicate?
A.Fixed upper airway obstruction
B.Variable extrathoracic airway obstruction
C.Variable intrathoracic airway obstruction
D.Chronic obstructive pulmonary disease
Flow volume loop
from a healthy subject
Severe obstructive disease
Obstructive airway disease
Fixed major airway obstruction
Restrictive lung disease
Fixed upper-airway
obstruction
(intrathoracic or
extrathoracic).
Variable
extrathoracic
obstruction.
Variable
intrathoracic
obstruction.
What time period is generally used to measure
MVV?
A.6 to 8 seconds
B.12 to 15 seconds
C.30 to 40 seconds
D.40 to 60 seconds


Maximum Voluntary Ventilation: tests the ability of
the patients chest muscles to expand and contract
Pt breaths in and out as fast as possible


Normal 170 L/min
Decreased in

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
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
Obstructive dz
Increased Raw
Muscle weakness
Decreased
compliance
poor patient effort
The best way to check the accuracy of a waterseal spirometer is to use a
A.3-L syringe.
B.pneumotachometer.
C.vortex sensor.
D.Wright respirometer.
Calibration




Volume: 3 L syringe
Flow: rotometer
Timing devices: stopwatch
Plethysmograph


Rotometer for flow
Barometer for pressure
After a resting expiration, air still remains in the
lungs. What is this volume called?
A.FRC
B.VC
C.RV
D.ERV
Know your lung volumes and capacities!
3000 ml
3500 ml
4500 ml
1000 ml
2500 ml
1500 ml
Memorize numbers from Persing.
Egan fig. 17-1
During each cycle of normal quiet breathing, a
volume of gas is moved into and out of the
lungs. What is this cyclical volume called?
A.IRV
B.Tidal volume (VT)
C.ERV
D.Vital capacity (VC)
Which of the following volumes or capacities
cannot be measured by simple spirometry?
I. Functional residual capacity ( FRC)
II. Expiratory reserve volume ( ERV)
III. Residual volume (RV)
IV.Inspiratory reserve volume ( IRV)
A. I, III, and IV
B. I, II, III, and IV
C. I and III
D. I and IV
Egan fig. 17-1
Which of the following is equal to total lung
capacity (TLC)?
A.VT + ERV + IRV + RV
B.IC + VT + ERV
C.VC + ERV
D.FRC + IRV
Egan fig. 17-1
A patient has a VC of 4200 ml, an FRC of 3,300
mL and an ERV of 1500 ml. What is the RV?
A.5700 ml
B.2700 ml
C.1800 ml
D.7500 ml
Egan fig. 17-1
Which of the following is a true statement?
A.VC = FRC + VT
B.VC = IRV + VT + ERV
C.VC = VT + IRV + RV
D.FRC = VT + ERV
Egan fig. 17-1
What is the amount of gas that can be inhaled
over and above that which is normally inhaled
during quiet breathing?
A.FRC
B.ERV
C.IRV
D.VC
Egan fig. 17-1
After the most strenuous expiratory effort, air still
remains in the lungs and cannot be removed
voluntarily. What is this volume called?
A.IRV
B.RV
C.ER
D.FRC
Egan fig. 17-1
What is the amount of gas that can be exhaled
below the resting expiratory level?
A.ERV
B.RV
C.FRC
D.VC
Egan fig. 17-1
Which of the following is the maximum
amount of air that can be exhaled
from the maximum inspiratory level?
A.vital capacity
B.residual volume
C.functional residual capacity
D.expiratory reserve volume
Egan fig. 17-1
How can you ensure reliability when measuring
the ERV?
A.Have the patient perform the maneuver twice,
assure consistency, then take best value.
B.Have the patient perform the maneuver 3
times, then take the last value.
C.Have the patient perform the maneuver twice,
assure consistency, then take mean value.
D.Have the patient perform the maneuver until
they become fatigued, then take the last value.
A patient has an expired minute ventilation of
14.2 L and a ventilatory rate of 25/min. What is
the average VT?
A.568 ml
B.635 ml
C.725 ml
D.410 ml
The respiratory therapist instructed a
patient to take a deep breath and then
exhale as quickly as possible. The
therapist observed a recording of the
fastest air movement. Which of the
following was measured?
A. peak flow
B. vital capacity
C. FEV 1
D. FEF 25-75%
A patient has a prebronchodilator peak
expiratory flow rate (PEFR) of 4.5 L/sec. The
postbronchodilator value is 5.0 L/sec. What
is the percent change?
A.11
B.22
C.33
D.50
Peak Flow

Normal



Percent Change


400 – 600 L/min
6.5 – 10 L/sec
Post – Pre x 100
Pre
Percent Predicted

Actual x 100
Predicted
Which of the following is being measured if a
respiratory care practitioner instructs a patient to
take a maximum deep breath and then exhale
as much and as fast as possible?
A.RV
B.VC
C.TLC
D.FVC

97%
FVC = volume
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
75%
 Restrictive
Obstructive

60%

FEVtime = flow

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
94%

 Restrictive
 Obstructive
So look at FEV1/FVC%
FEV1/FVC %
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Egan fig. 17-5
 FVC with Normal SVC
Normal in Restrictive
 Obstructive
A patient has a predicted FEV1 of 4.2 L and a
measure FEV1 of 3.5 L. What is the predicted
FEV1 in percent?
A.76
B.83
C.92
D.120
A patient with chronic obstructive pulmonary
disease (COPD) has a normal slow vital
capacity (SVC) of 3400 ml and an FVC of
2300 ml. Which of the following mechanisms
best explains this difference?
A.Airway trapping during forced expiration
B.Muscle fatigue during forced expiration
C.Decreased compliance during forced
expiration
D.Poor instruction by the pulmonary technologist
Compared to predicted normals, a patient has an
increased RV and a decreased percent
FEV1/FVC. Test results are repeatable. Which
of the following is most likely the underlying
problem?
A.Generalized obstruction with air trapping
B.Poor patient effort during the test
C.Restrictive disorder of the lungs
D.Combined restrictive and obstructive disease
Compared to predicted normals, a patient has a
reduced TLC and a decreased percent
FEV1/FVC. Test results are repeatable. Which
of the following is most likely the underlying
problem?
A.Poor patient effort during the test procedure
B.Restrictive disorder of the lungs or chest wall
C.Combined restrictive and obstructive disease
D.Peripheral (small) airway obstruction
What is the term for the standard measure of the
average expiratory flow during the middle
portion of an FVC maneuver?
A.FEV1
B.FEF200-1200
C.PEFR
D.FEF25%-75%
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
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Egan fig. 17-8
FEF 25% - 75%
Decreased in
early obstructive
disease
Associated with
small (peripheral)
airway obstruction
Typically 5 L/sec
Compared to predicted normals, a patient has a
normal percent FEV1/FVC, but a reduced
FEF25%-75%. Test results are repeatable.
Which of the following is most likely the
underlying problem?
A.Combined restrictive and obstructive disease
B.A restrictive disorder of the chest wall
C.Severe central (large) airway obstruction
D.Peripheral (small) airway obstruction
Compared to predicted normals, a patient has a
normal percent FEV1/FVC, normal FEF25%75%, but a markedly reduced FVC. Test results
are repeatable. Which of the following is most
likely the underlying problem?
A.Poor patient effort during the test procedure
B.Combined restrictive and obstructive disease
C.A restrictive disorder of the lungs or chest wall
D.Severe central (large) airway obstruction
What is the term for the standard measure of the
average expiratory flow during the first 1000
mL after 200 mL is expired?
A.FEV1
B.FEF200-1200
C.PEFR
D.FEF25%-75%
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Egan fig. 17-7
FEF 200-1200
Decreased in large
airway obstruction
Typically = 8 L/sec
For you to characterize a patient as having a mild
impairment on a measured pulmonary function
parameter, it should fall within what range of the
predicted value?
A.80% to 120%
B.80% to 100%
C.60% to 79%
D.40% to 59%
What conclusions can you draw from the following data,
obtained on a 32-year-old 53 kg woman admitted for
elective surgery?
ACTUAL
TLC
4.93
FRC
2.41
RV
1.29
VC
3.64
PRED
5.27
2.43
1.35
3.86
%PRED
94%
99%
96%
94%
|
ACTUALPRED %PRED
|FVC
3.67
3.86
95%
|FEV1% 84%
75%
|FEF200–1200
5.66
5.74
99%
|FEF 25%–75% 3.53
3.49
101%
A.Results indicate a mild restrictive lung disorder.
B.Results indicate normal pulmonary function.
C.Results indicate a combined disease process.
D.Results indicate generalized airway
obstruction.
What conclusions can you draw from the following data, obtained on
a 67-year-old 76 kg man admitted for pulmonary complications
arising from silicosis?
Actual
Predicted
% Predicted
TLC
4.34
7.73
56%
FRC
1.73
4.36
40%
RV
1.45
2.63
55%
VC
2.89
4.74
61%
FVC
2.86
4.74
60%
FEV1
96%
75%
FEF 200-1200
6.89
6.71
103%
FEF 25%-75%
2.78
2.88
96%
A.
B.
C.
D.
Results indicate generalized airway obstruction.
Results indicate normal pulmonary function.
Results indicate a combined disease process.
Results indicate a restrictive lung disorder.
What conclusions can you draw from the following data, obtained from
a 41-year-old man who admits to "occasional smoking" but
otherwise reveals no past history of pulmonary problems?
Actual
Predicted
% Predicted
TLC
4.75
4.90
97&
FRC
2.31
2.21
105%
RV
1.28
1.20
106%
VC
3.48
3.63
96%
FVC
2.96
3.63
82%
FEV1
80%
75%
FEF 200-1200
4.33
5.45
82%
FEF 25%-75%
1.95
3.37
58%
A.
B.
C.
D.
Results indicate small airway obstruction.
Results indicate generalized airway obstruction.
Results indicate a restrictive lung disorder.
Results indicate a combined disease process.
The following pulmonary function results are obtained for
patient:
Predicted Observed % Predicted
Which of the following is the most likely conclusion?
A.severe obstructive pattern
B.severe restrictive pattern
C.mild obstructive pattern
D.mild restrictive pattern
The information below was obtained from the
pulmonary function report for a
40-year-old male who weighs 73 kg (161 lb) and is
177 cm (5 ft 9 in) tall:
There is no significant response to the
bronchodilator. These data most strongly suggest
A.interstitial fibrosis.
B.emphysema.
C.chronic bronchitis.
D.cystic fibrosis.
Spirometry testing reveals results below:
With which of the following are these values
the most consistent?
A. acute asthma
B. normal lung function
C. small airway obstruction
D. pulmonary fibrosis
A patient has the pulmonary function results
shown below:
Which of the following is the most appropriate
interpretation of these results?
A.bronchitis
B.restrictive disease only
C.obstructive disease only
D.mixed restrictive and obstructive disease
The End

Three liters of air are injected into a water-seal spirometer
from a certified-volume standard syringe. The observed
tracing shows 2.6 L. Which of the following should the
respiratory therapist conclude about the disparity? A. The
plunger was pushed too slowly. B. The difference is within
the acceptable error range. C. The time scale was incorrectly
calibrated. D. There was a leak in the system.
EXPLANATIONS: (u) A. The flow of gas into the spirometer
should not affect the accuracy of its volume. (u) B. This is
outside the 10% acceptable error range. (u) C. The volume
deflection is unaffected by the time scale. (c) D. A leak is the
likely cause for the difference of 400 mL and is one of the
reasons for checking spirometers with a calibrated syringe.