Lung Testing - B (Module) Flashcards
The volume of gas remaining in the lung at the end of a maximal expiration is best defined as
A. residual volume
B. total lung capacity
C. functional residual capacity
D. tidal volume
A. residual volume
Which of the following methods can be used to measure static lung volumes
- spirometry
- radiological estimation
- helium dilution
A. 1 only
B. 2 only
C. 2 and 3 only
D. 1 and 3 only
C. 2 and 3 only
The 4 methods that can measure RV and the associated “static lung volumes” are:
helium dilution
nitrogen washout
radiological estimation
body box
While performing a helium dilution test on a 48 year old female patient, the pulmonary function technologist records the following values:
Time: (minutes) % Helium
- 0 8.97
- 0 7.55
- 0 6.97
- 0 6.81
- 5 6.81
- 0 6.80
Based on this information, the technologist should
A. continue the test until equilibration has occurred
B. terminate the test
C. repeat the test over a 10 minute period
D. check for a leak in the system
B. terminate the test
Per the study guide, the test is not complete until the He concentration does not change by more than 0.02% in 30 seconds.
If you get 3 values that are essentially the same, you can stop the test. You have reached equilibration.
Note: If you go beyond equilibration, the helium value may rise, because you are consuming gas volume (O2) making the ratio of helium to other gases increase.
The technologist measures the MEP value for a patient complaining of generalized muscle weakness and records the following values:
Trial 1 - 58cm H2O
Trial 2 - 62cm H2)
Trial 3 - 50cm H2O
These results are consistent with
A. the patients’ symptoms
B. pulmonary fibrosis
C. normal lung function
D. pulmonary edema
A. the patient’s symptoms
Normal MEP on the audio lecture is about 80cm H20.
*page C-26
Book states normal is 80-100
A patient has a 50 pack-year smoking history and a measured COHb level of 12%. The patient’s measured diffusion capacity is 10 mL/CO/min/mm Hg. Which of the following is the most likely explanation for the DLCO value?
A. decreased binding sites for CO
B. increased capillary blood volume
C. high alveolar PCO2 values
D. back pressure created by CO Hb level
D. back pressure created by CO Hb level
Remember, normal DLCO is 25, so the patient’s 10 is low.
If the patient has a CO Hb of 12% it will be harder for additional CO to diffuse into the blood because of backpressure.
The pulmonary function technologist performs a mannitol challenge test on a 24-year-old patient with a history of intermittent asthma. The patient had a 16 % decrease in her measured FEV1 value with the test. The technologist should
A. continue the test until there is a 20% drop in the FEV1
B. instruct the patient to perform an FVC maneuver
C. administer an aerosolized SABA agent
D. administer a mixture of 5% CO2, 21% O2, and balance N2.
C. administer an aerosolized SABA agent
The mannitol challenge test stops once a 15% drop in FEV1 occurs.
Once the test is completed, you want to reverse the effect, so you’d administer a SABA such as albuterol
A patient in the ICU has a tracheostomy tube in place. The pulmonologist would like to measure the patient’s TLC value. The technologist determines that the patient is unable to perform the typical methods for testing and should suggest the measurement be obtained by
A. esophageal balloon
B. boyle’s law
C. radiologic estimate
D. MIP measurement
C. radiologic estimate
The 4 ways to measure static lung volumes (any volume including RV)
helium dilution
nitrogen washout
radiologic estimation
body box
The patient cannot perform normal PFT’s because of their trach. Of the 4 choices only radiologic estimation would not be affected by a trach.
While performing the helium dilution method to measure a patient’s FRC, the technologist notes that the spirometer baseline volume is fluctuating. Which of the following best describes the cause of the drifting baseline?
A. low pressure in the helium cylinder
B. the test was started at an incorrect volume
C. oxygen is being consumed by the patient
D. deadspace in the breathing valve
C. oxygen is being consumed by the patient
Helium dilution is a closed system method. The rebreathing will consume oxygen, causing the baseline volume to fall.
“baseline volume is fluctuating” is the key clue in this question.
*Remember you will always need a CO2 scrubber for a rebreathing test.
While performing the helium dilution method to measure a patient’s FRC, the technologist should continue testing until
A. the patient rebreathes the helium concentration for a period of 7 minutes.
B. the helium concentration changes by less than 0.02% over a 30 second interval.
C. the helium concentration begins to rise.
D. a consistent spirometer volume is obtained during the testing period.
B. the helium concentration changes by less than 0.02% over a 30 second interval.
*page C-7
The test can be conducted for up to 7 minutes as stated in choice A, but is usually concluded earlier. B is the better answer.
Note: the helium concentration beginning to rise is an indication that there is no leak (can be described as a “tight seal” on the exam as well), because the patient is consuming the O2 and increasing the ratio of CO compared to other gases in the baseline volume.
The pulmonary function technologist is preparing for an FRC measurement using the helium dilution method. The technologist notices that the helium cylinder pressure is 50 psi. The technologist should
A. refill the cylinder to a pressure of 2200 psig.
B. proceed with the test.
C. replace the cylinder with a full tank of helium.
D. decrease the flow from the cylinder during the test.
C. replace the cylinder with a full tank of helium
Any cylinder with 50psi should be replaced.
Full cylinders are 2200 psi.
The pulmonary function technologist is preparing for FRC measurement using the nitrogen washout technique. As the patient starts the test, the nitrogen concentration steadily drops at a consistent rate. After 2 minutes of testing the following pattern is observed:
Link: https://ketteringseminars.com/graphics/Q6540.PNG
Image: Lung Testing - B - Question 11
The technologist should conclude that
A. moisture entered the system during the test.
B. the patient has obstructive lung disease.
C. this is normal for N2 washout testing.
D. the patient removed the mouthpiece during testing.
D. the patient removed the mouthpiece during testing
(they let N2 into the system, and it increased the reading)
*page C-10
The spike is sustained and starts dropping from a higher value than before it spiked.
If the spike is measured and the N2 continues to decrease from the point that it left off at before the spike, it would likely be moisture.
While performing FRC measurement utilizing the body box the pulmonary function technologist observes artifact on the monitor during testing. To correct the problem the technologist should instruct the patient to
A. exhale with more force during the next maneuver.
B. continue panting but at a faster frequency until told to stop
C. place his hands on the sides of his face during the procedure.
D. remove the nose clips for the remainder of the test.
C. place his hands on the sides of his face during the procedure.
While panting, artifacts are commonly caused by jaw movement.
*page C-21
While performing a DLCO procedure on a 46-year-old patient, the recorded VC is 5.5 L from spirometry testing. During the DLCO procedure, the patient exhales to residual volume and quickly inhales to TLC while breathing a gas mixture of 0.3% CO, 10% He, 21% O2 and the balance N2. The patient’s inspired volume is measured at 4.4 L. The pulmonary function technologist should
A. repeat the procedure until an inspired volume of at least 4.6 L is obtained.
B. accept the measured volume of 4.4 L and proceed with testing.
C. instruct the patient to begin the test at normal end expiration.
D. adjust the inhaled gas mixture to 0.5% CO.
A. repeat the procedure until an inspired volume of at least 4.6 L is obtained.
The minimum requirement for VC during DLCO testing is 85%.
*page C-28
This is ALWAYS asked on the exam, according to the narrator of the program.
The pulmonary physician has written an order for a single breath CO diffusion test on an 81-year-old patient with sarcoidosis. The patient arrives in the pulmonary lab and seems confused by the pulmonary function technologist’s instructions. The technologist should recommend
A. cancelling the test and contacting the physician.
B. using the steady state technique.
C. using the intrabreath CO diffusion procedure.
D. application of the membrane diffusion coefficient factor.
B. using the steady state technique (DLCO-SS)
*page C-29
The DLCO-SS is ideal for patients with difficulty following instructions. It doesn’t require following instructions. The patient simply has to breath the gas mixture containing 0.1%-0.2% CO in air for 5-6 minutes.
Remember, with a DLCO-SS, you will need to do an ABG afterward, and this makes the procedure INVASIVE.
The pulmonary function technologist is interviewing a patient who is scheduled for a mannitol challenge test. The patient states that he had a recent viral infection that subsided four days ago. The technologist should
A. proceed with the test as planned.
B. schedule the test at the end of the day.
C. administer a SABA before beginning the test.
D. re-schedule the test in three weeks.
D. re-schedule the test in three weeks
*page C-17
Viral infections are different from bacterial infections.
For bacterial infections like TB, you can schedule at the end of the day.
A viral infection is dangerous for up to 3 weeks, so you’d want to re-schedule outside of that window.
