Lung Testing - A (Module)

Question 1

Which of the following is a typical value for funtional residual capacity?

A. 1200ml
B. 2400ml
C. 4800ml
D. 6000ml

Answer 1

B. 2400ml

Question 2

Which of the following is the correct formula to determine total lung capacity?

A. ERV + RV
B. VC + RV
C. FRC - ERV
D. VC - IC

Answer 2

B. VC + RV

Question 3

The pulmonary function technologist performs an FRC measurement using the helium dilution method. During the test, the technologist notices that the spirometer baseline value is decreasing as the test progresses. In order to maintain a consistent baseline during the test, the technologist should

A. reduce the concentration of helium

B. add a small amount of oxygen to the system

C. continue testing until the baseline stabilizes

D. subract a small volume from the final test results

Answer 3

B. add a small amount of oxygen to the system.

Remember, helium dilution is a closed system test. If you consume the oxygen in the system, it will reduce the baseline. You should replace it.

Also remember that in rebreathing tests like helium dilution, you will always need a scrubber.

Question 4

With a patient inside a body box, the pulmonary function technologist has the patient pant to form an “S-shaped” curve on the screen. The technologist then instructs the patient to exhale. At the end of a normal exhalation, the shutter closes and a second curve is produced. These two curves allow for calculation of

A. C-lt
B. R-aw
C. G-aw
D. SG-aw

Answer 4

B. Raw (airway resistance)

The body box is used for 2 things:

Airway Resistance
FRC (aka Vtg)

C-lt is associated with the esophageal balloon

G-aw is airway conductance.

SG-aw is specific airway conductance

Question 5

A patient with severe air trapping has a measured diffusion of 20 mL/CO/min/mm Hg. The most likely explanation is

1. deceased surface area.
2. muscle weakness.
3. ventilation / perfusion abnormality.

A. 1 only
B. 2 only
C. 2 and 3 only
D. 1 and 3 only

Answer 5

D. 1 and 3 only

The clues are “air trapping” and a low DLCO (normal is 25)

You should associate air trapping with an obstructive disease. Emphysema is the only obstructive disease that has a decreased DLCO.

Emphysema also causes decreased surface area due to lung tissue distruction, and a ventilation/perfusion abnormality (air trapping).

Question 6

A patient with normal spirometry has a measured DLCO value of 29 mL/CO/min/mm Hg. Which of the following is the most likely explanation for this DLCO value?

1. Exercise before testing
2. Hemolytic anemia
3. High capillary blood volume

A. 1 only
B. 2 only
C. 1 and 3 only
D. 2 and 3 only

Answer 6

C. 1 and 3 only

DLCO is increased (normal is 25)

exercise before testing will increase blood movement and pick up more CO.

anemia will cause a low DLCO because the Hb will be low.

high capillary blood volume would also increase CO diffusion much like increased RBC’s or Hb.

Question 7

A patient had the following results from a methacholine test

Dose/                    FEV1
Baseline/               4.2
0.00/                      4.1
0.31/                       3.9
0.60/                      3.7
1.25/                       3.3
2.50/                      2.8

What is the percent change in FEV1 after 1.25mg/ml of methacholine was administered?

A. 5%
B. 10%
C. 20%
D. 25%

Answer 7

C. 20%

Simple math.

Remember that a methacholine test is done once 20% change is reached. The provocative dose is the amount of methacholine that was given resulting in the 20% reduction in FEV1

Question 8

During measurement of V-tg utilizing the body plethysmograph, the pulmonary function technologist has the patient breathe normally for several breaths. At end-expiration, the technologist closes the shutter and has the patient pant. At this point there is no air-flow present, allowing estimation of

A. alveolar pressure
B. residual volume
C. box pressure
D. restrictive disease

Answer 8

A. alveolar pressure

Associate alveolar pressure with “panting”. The described maneuver is one of the parts used to measure airway resistance

*page C-18

Note: Box pressure will be measured independently of any mouth pressures, and is not the right answer.

Question 9

While performing a nitrogen washout test to measure a patient’s FRC, the pulmonary function technologist has the patient breathe 100% oxygen for 4 minutes and notes that the N2 concentration is 4%. The technologist should

A. stop the test and record the results

B. add a CO2 absorber in the circuit

C. re-calibrate the nitrogen analyzer

D. continue testing until the % N2 is less than 1%

Answer 9

D. continue testing until the % N2 is less than 1%

The test isn’t over until either 7 minutes has passed or < 1% N2 is reached.

*page C-9

Question 10

The pulmonary function technologist has completed FRC measurements on a 54-year-old patient using the helium dilution technique. The patient’s measured FRC values are: 2.75 L, 2.78 L and 2.74 L. To determine the patient’s RV, the technologist would

A. obtain the ERV value from spirometry

B. subract the VC from the FRC measurement

C. repeat the test and directly measure the RV

D. add the residual volume to the FRC value

Answer 10

A. obtain the ERV value from spirometry

Once you have the FRC, you can subtract the ERV from it to find the RV.

None of the other options would result in a RV.

Question 11

The pulmonary function technologist monitors the patient during an FRC measurement using the helium dilution method. The patient appears to have an increase in respiratory rate and tidal volume during the test. The technologist should suspect that

A. the patient is hypoxic

B. the scrubber is exhausted

C. the helium analyzer has failed

D. there is an air leak in the system

Answer 11

B. the scrubber is exhausted

Helium dilution is a rebreathing technique.

Tachypnea and feeling hot are indications of CO2 rebreathing.

If the patient is exhibiting signs of CO2 rebreathing, suspect the CO2 scrubber is missing or exhausted.

Question 12

While performing a nitrogen washout test on a 67-year-old man, the pulmonary function technologist observes the following nitrogen concentration on the monitor:

https://ketteringseminars.com/graphics/Q6541.PNG

See saved image “Lung Testing - A - Question 12”

The technologist should:

A. encourage the patient to continue the remainder of the test

B. have the patient seal his mouth tightly around the mouthpiece.

C. instruct the patient to hold his breath for 8-12 seconds.

D. stop the test and retest the patient again in 15 minutes

Answer 12

D. stop the test and retest the patient again in 15 minutes

the value reaching “Log % (1.0)” means the result is less than 1% so the test is done.

A nitrogen washout test is completed when the N2 is below 1% or 7 minutes has passed.

Question 13

While performing lung compliance measurements utilizing the esophageal balloon technique the pulmonary function technologist notes that the balloon is positioned 50 cm from the patient’s nose. The technologist should instruct the patient to

A. exhale and hold his breath with the tap open

B. swallow three times and advance the catheter to 55cm

C. withdraw the caheter to the 45cm mark

D. perform a Mueller maneuer against a closed shutter

Answer 13

D. perform a Mueller maneuver against a closed shutter.

The correct placement in the module is 50cm from the nose.

The Mueller maneuver will squeeze all the air out of the balloon, so that you can refill with EXACTLY 0.5ml.

Question 14

The pulmonary function technologist performs a DLCO-SB test on a 67-year-old male patient. During the procedure, the technologist notes significant variations in the patient’s breath holding time during each of the trials completed. The technologist should

A. decrease the washout volume to account for the diferences

B. use a stop watch to verify breath holding time

C. assure the inspired volume is at least 85% of the VC

D. instruct the patient to inhale and exhale rapidly

Answer 14

D. instruct the patient to inhale and exhale rapidly

Ideally when correctly performing a DLCO-SB, the patient should hold the breath for 10 seconds. (page C-28) This would make B a great answer.

However, this is kind of a trick question. According to the module audio, you have to recognize that the patient is unable to perform the maneuver correctly and modify the maneuver. There is no supporting text for this answer.

The answer on the module is D.

Question 15

While performing a multiple breath N2 washout test, a 71-year-old patient reaches a nitrogen concentration of less than 1% within the first three minutes and has been able to reproduce the results. The pulmonary function technologist should

A. continue testing for the full 7 minutes

B. check the function of the oxygen tank

C. terminate the test and record the results

D. re-calibrate the Geissler tube analyzer

Answer 15

C. terminate the test and record the results

The patient has met the <1% goal in less than 7 minutes and has reproduced the results.