Spring/Summer 2018 Diagnostics Bulletin

Spring/Summer 2018 Diagnostics Section Bulletin

Jennifer Weltz Horpedahl, BSRT, RRT, RRT-NPS, RPFT, AE-C

Kadlec Regional Medical Center
Benton City, WA
Email: jennifer.weltz-horpedahl@kadlec.org

D’Aun Flesher, BSRT, RRT-NPS, AE-C
Presbyterian Healthcare Services
Albuquerque, MN
Email: dflesher@phs.org

Katrina Hynes, BAS, RRT, RPFT
Mayo Clinic Pulmonary Evaluation Laboratory
Rochester, MN 55905
(507) 284-4545

Former Chair
Matthew J O’Brien, RRT, RPFT
Pulmonary Diagnostic Lab
University of Wisconsin Hospital and Clinics
600 Highland Ave Room E5/520
Madison, WI 53792-5772
(608) 263-7001
Fax: (608) 263-7002

In this issue:

In Appreciation of Professor Philip H. Quanjer (1936-2017): Understanding his Legacy to Pulmonary Function Testing

Susan Blonshine, RRT, RPFT, AE-C, FAARC

Professor Philip H. Quanjer, an Emeritus Professor of Physiology at Leiden University in the Netherlands, was the co-founder of the European Respiratory Society (ERS) and European Respiratory Journal. His efforts to improve lung function testing standards and reliability of the reference values deserve immense appreciation from each of us in pulmonary diagnostics. His accomplishments have improved the early detection of respiratory disease.

Professor Quanjer received his medical degree from Groningen University. He ultimately was awarded the Chair in Respiratory Physiology at Leiden University in 1980 after finishing his PhD on “Plethysmographic evaluation of airway obstruction” in 1970.

He was an active member of multiple committees, serving on the first joint task force convened by the ERS and American Thoracic Society on infant lung function. Creation of Assembly 9 of the ERS (which includes lung function technologists and scientists, physiotherapists, and nurses) was driven by Professor Quanjer. He served as the scientific secretary of the European Steal and Coal Community on “Standardization of Lung Function Tests” from 1978 to 1994.

Lung function reference equations were a central focus of his work, from publication of the 1983 reference values in the early European documents on standardization of lung function tests to the more recent publication in 2012 of the “multi-ethnic reference values for the 3-95-year age range.”

This 2012 publication was a part of the ERS Global Lung Initiative (GLI) that started with spirometry reference values in the 2012 publication and progressed to DLCO reference values published in 2017. The GLI continues to move forward with lung volume reference values as the next initiative.

This may be the most lasting legacy from Professor Quanjer, as he pioneered this effort and provided tireless unfunded support to this group. The use of z-scores rather than percent of predicted in the assessment of lung function results was also defended by him and contributes to our improved understanding of healthy aging.

The ERS has agreed to continue support of his work, with multiple resources on the SpirXpert website offering free and open access.

We are all privileged that he was a part of the respiratory care community and grateful that he dedicated his life to improving our understanding of lung function both today and far into the future.


  • Stocks J, Steenbruggen I. In memorium: Professor Philip H. Quanjer. Eur Respir J 2017;50:1-4.
  • Quanjer PH. Standardized lung function testing. Report working party. Bull Eur Physiopathol Respir 1983;19:Suppl 5,1-95.
  • Quanjer PH, Stanojevic S, Cole TJ, et al. Multi-ethnic reference values for spirometry for the 3-95-yr range: the global lung function 2012 equations. Eur Respir J 2012;40:1324-1343.
  • Stanojevic S, Graham BL, Cooper BG, et al. Official ERS technical standards: Global Lung Function Initiative reference values for the carbon monoxide transfer factor for Caucasians. Eur Respir J 2017;50:1700010.

2017 AARC Congress Diagnostic Section Highlights

Jennifer Weltz Horpedahl, BSRT, RRT, RRT-NPS, RPFT, AE-C

I had the privilege of attending the AARC Congress held in Indianapolis this past fall. It was a fantastic meeting with very informative diagnostic symposia and presentations. Although I was not able to attend every diagnostic session, I wanted to share some highlights with you all.

Carl Mottram and Katrina Hynes hosted a symposium on the ATS pulmonary function laboratory accreditation and what they have been doing in the Mayo system to be accreditation-ready. They have worked tirelessly to develop a program to monitor test quality and compliance to technical standards, not only in the hospital but also in outpatient clinic settings. To streamline communication and availability of resources they are utilizing a SharePoint that allows access to standardization of policy and procedures, how-to videos, and reporting documents. Some tips to start getting your facility ready:

  • Ensure your lab’s policies and procedures are up to date.
  • Take a look at the quality control program for your lab and make sure the recommended daily, weekly, and monthly checks and biologic controls are being done.

Gerald Zavorsky gave a very interesting presentation about the physiologic, clinical, and technical differences between DLCO measurements. Some key points from his presentation were the tighter reproducibility of DLNO compared to DLCO and how DLNO is unaffected by Hb, COHb, or PaO2 in contrast to DLCO. Unfortunately for those doing testing in the U.S., no commercial testing software is currently available, but I think this is something we will be seeing and hearing much more about in the future.

Garner Faulkner gave attendees a fantastic overview of the measurements and testing options currently being utilized for patients with neuromuscular disease, including spirometry, MIP/MEP measurements, SNIP, and cough peak flow, or CPF. For this patient population, these tests are helpful not only for monitoring but to help them qualify for support devices. If your lab is looking to develop or strengthen diagnostic services for neuromuscular services, Garner would be a great resource.

Kathleen Clark, from the National Institute for Occupational Safety and Health (NIOSH), presented on spirometry in the occupational setting and the implementation of a national spirometry facility network for the Coal Workers’ Health Surveillance Program. The work done by NIOSH to identify at-risk workers and assist the employer to implement changes that preserve workers’ lung function is remarkable and invaluable.

This would not be possible without the NIOSH Spirometry Training Course taught throughout the country. This course ensures attendees are taught current ATS recommendations with a curriculum that follows professional guidelines and gives students lots of hands-on practice.

The skills they learn through the course help ensure that tests reported to the NIOSH surveillance programs are accurate and reliable. In the coal industry, a specially designed program has been implemented to collect standardized reports through a secure database. Facilities participating in this program are approved by NIOSH and currently reside in 11 states.

Susan Blonshine’s presentation on the management of work-related asthma brought attention to various sensitizers and triggers in the workplace. I was surprised to learn that there are more than 2000 new substances developed each year that are not tested for their potential to cause or exacerbate asthma. The products that can cause work-related asthma are many, as are the potential asthma triggers. Unfortunately for some, this can result in death. As technicians, our pretest interview provides an opportunity to help identify a work-related sensitizer or trigger.

Jeff Haynes gave a wonderful overview of the 2017 ERS/ATS DLCO technical standards. While I would love to include his entire presentation, that really deserves its own article.
Calibration and quality control changes were made with this standard, and Jeff stressed the importance of performing these checks to ensure accurate test results.

His next presentation on PFT interpretation was a good reminder that obtaining quality testing is necessary for accurate PFT interpretation or, as he said, “Garbage in, garbage out.” Quality starts before the test begins, with the quality control process, patient assessment, and proper height measurement, but it doesn’t end there. Choosing the proper reference set for your patient population is essential.

Jeff concluded this series discussing normal vs. abnormal interpretation of PFTs and the various methods out there for interpreting pulmonary function tests. Jeff discussed the advantages of using z-scores compared to fixed ratios and gave a good review of how fixed scores can result in misdiagnosis for patients.

The theme of the 2017 diagnostic presentations at the Congress really was quality: ensuring you are getting quality test results, implementing quality systems in the lab, and if necessary, implementing quality control programs. There have been a lot of changes in the diagnostic world over the last year, and after listening to these presenters, I anticipate many more to come.

I hope you will make plans to attend AARC Congress 2018 in Las Vegas this Dec. 4-7, where we will once again enjoy a great set of diagnostic lectures from leading technologists.

Submaximal Initial Inspirations in Forced Spirometry… or, “The Red Flag FVC”

James Sullivan, BA, RPFT

A recent thread on the Diagnostics Section discussion list was the impetus for this article. A question was raised about submaximal inhalation errors in forced spirometry, and many helpful responses and discussions ensued. It was quite productive, and I felt this discussion displayed one of the best reasons to belong to the Diagnostics Section. Where else can you pose a question to the country and beyond for answers? I encourage everyone to contribute to these discussions, and to start similar ones of their own.

It’s a fairly busy day in the pulmonary labs. Your next patient is a pleasant, middle-aged woman with moderate obstructive disease. She appears to easily understand your instructions, and she coordinates the FVC maneuver well.

The first three trials are acceptably performed and are repeatable, so you move on to plethysmographic lung volumes. Her performance is impeccable, with three Vtg – VC maneuvers all meeting acceptability and repeatability criteria, and the SVC is 0.012 L > than the FVC.

You then perform the first DLCO maneuver. She again performs a textbook maneuver, but the IVC is more than 300 mL greater than the largest measured VC. What’s wrong?

As you think about it, you recall a patient you saw earlier, who appeared to perform the FVC maneuver well, but the inspiratory flow-volume loop overshot the start of the expiratory flow-volume loop. The forced vital capacity measurement is inaccurate unless started at TLC. This was a red flag that something was wrong.

What was wrong?

chart graphic

If the maneuver is performed correctly, the measurement will be accurate.

This has always been the Golden Rule of pulmonary function testing. Our primary role as pulmonary technologists is to get the patient to perform the breathing maneuver correctly, and to get the analyzers to measure correctly.

If the maneuver is performed correctly AND the analyzer is measuring correctly, the measurement will be accurate.

Allow me to make a correction to the classic lung function Golden Rule. To achieve accurate results, we first need to ensure the system is calibrated correctly and is accurately measuring flow. Perfect patient performance on an inaccurate system will yield the same imperfect results as a patient with zero ventilatory coordination on a system with 100% accuracy.

A system that returns an average of 2.94 L (-2%) on expiration and 3.06 L (+2%) on inspiration, or vice versa, is technically performing acceptably, but there’s a 4% difference between expiratory and inspiratory flows. Personally, I would never accept a calibration like this. The 2005 ATS/ERS Standardization of Spirometry only states (in part) that the spirometer should be capable of “measuring volumes of ≥ 8 L (BTPS) with an accuracy of at least ± 3% of reading or ± 0.050 L, whichever is greater, with flows between 0 and 14 LPS.”

I think the ATS/ERS does a pretty good job with a difficult task, but they are the first to admit that the standards they publish are never complete or perfect; they’re always a work in progress. A limitation (which hopefully will be addressed in future releases) is that there’s nothing at all regarding criteria for an acceptable range of differences in flow error between inspiratory and expiratory flows.

The above-mentioned system is understating expiratory flows (and likewise, volumes) by 2%, and is overstating inspiratory flows and volumes by 2%. A system with disparate inspiratory-expiratory tidal flow measurement will often display a tidal baseline that will drift up or down. If your system is measuring low flows acceptably and higher flows inaccurately, or low flows inaccurately and high flows acceptably, you’ll see either a baseline drift or flow-volume loops that don’t match.

Technologist performance greatly affects patient performance.

In my experience, equipment inaccuracies are seldom the reason for problems like those described above. Poor, incorrect maneuver instructions by the technologist, followed by inadequate or nonexistent feedback to the patient regarding his or her performance are the most common causes of suboptimal pulmonary diagnostic measurements. Simply put, technologist performance greatly affects patient performance.

Back to our patient: if her VC is 3.00 L, this system will measure the FEVC as 2.82 L and the FIVC as 3.18 L. Voilà, the FIVC is overshooting TLC! This is a pretty simplistic and perhaps exaggerated example, but it illustrates how the system must accurately measure all clinically relevant flows.

Let’s get goofy!

Now that we’ve established that the system is operating correctly, let’s discuss the patient’s coordination of the maneuver. Did you accurately instruct and demonstrate the performance of the FVC maneuver? Are you watching the patient or the screen?

Watching the screen was what happened with “The Red Flag FVL” above. Is the patient moving in a manner needed for maximal performance? One of the responses in the Diagnostics Section discussion mentioned looking for a patient’s “goofy sign,” defined as a change in the appearance of the face (eyes widened, eyebrows raised) when someone is at full inflation. Often the head starts to quiver, evidence of isometric contraction of the accessory muscles of inspirations, which can only occur at TLC. If the patient’s movements do not appear maximal, the feedback to your patient between maneuvers should address this.

Let the flow-volume loops teach you about the patient.

I always tell technologists that the flow-volume loop may teach you something about the patient’s coordination. In this instance, the flow-volume loops suggest that this patient may coordinate maximal inspirations better when they are performed quickly. We’re really not measuring anything on the initial VT → TLC inspiration, so the speed of this inspiration isn’t important. Some may attain TLC better with a smooth inspiration, while others may do better inhaling quickly (although I’ve had many patients not reach TLC when they inhale very quickly; I think the word “brisk” is the best description for the initial inhalation).

But wait — there’s more!

The flow-volume loop also suggests that this patient may attain TLC more consistently when the inhalation starts below VT. During tidal breathing, I instruct my patients to continue an exhalation out a little further than normal. I never have them go all the way to RV (which can be quite fatiguing), but I have them continue for just a few seconds into their ERV. I then instruct them to inhale quickly to TLC, and then blast it out. By doing this, you’re instructing the maneuver in the manner the patient appears to be able to coordinate best.

Question: Did our obstructive patient perform the SVC too quickly, causing air trapping and thereby understating the SVC measurement? It’s a possibility, which post-test can be difficult to judge. “Smooth” is the best description for the SVC exhalation; “brisk” is too fast for obstructive patients.

Another Question: One of the questions raised in the discussion was what an acceptable difference between FEVC and FIVC should be. I’d suggest the FIVC should never be more than 1% larger than the FEVC, and this is only to account for measurement errors within an acceptable range for our equipment. Anything greater than 1% and I’m reaching for the calibration syringe.

If the FIVC is greater than the FEVC, I will definitely reinstruct, demonstrate, and repeat the maneuvers. If the patient is unable to improve his or her performance, I would clearly document this in the post-test comments. I’m far less concerned about FIVC < FEVC than FEVC < FIVC, and I do see FIVC < FEVC fairly often. When I see this, I reinstruct the patient to try to really get his or her lungs as full as possible on the last inspiration, but as long as the inspiratory FVL clearly shows the status of the upper airways and is maybe within 90% of the FEVC, I’m pretty much okay with this.

Who’s better, US or them?

In the U.S., we’ve always performed the FVC and SVC maneuvers as >VT → TLC → RV → TLC, while in Europe it is performed as VT → RV → TLC → RV. Each method has its advantages and disadvantages.

The U.S. method is easier to perform, because the patient exhales to RV only once and, equally important, has the advantage of better showing when the FEVC was started below TLC. However, the U.S. flow-volume loop will not clearly show air trapping because the inspiratory and expiratory flow-volume loops are connected at RV.

The European method is harder to perform, because the patient must exhale to RV twice, but with the flow-volume loop not connecting at RV, it clearly shows air trapping. Also, the European FIVC will tend to be larger on obstructive patients compared to the U.S. method of FEVC and FIVC. This is because the initial exhalation to RV is smooth and unforced, minimizing the effects of airway obstruction.

When the sbDLCO maneuver is performed, we’re really performing the start of the European FVC, VT → RV → TLC, but we’re comparing the DLCO IVC with an expiratory VC. The more obstructive a patient is, the greater the difference between inspired and expired vital capacities will be. This is why our patient had a DLCO IVC more than 300 mL larger than the FVC.

What else can we do to optimize the patient’s ability to properly coordinate a maximal FVC maneuver?

Give control to the patient.

I’ve long been a fan of giving the patient control whenever possible. After measuring a few tidal breaths, I tell the patient, “When you’re ready, inhale as deeply as you can.” I don’t need to direct when they perform this inhalation. They may reach TLC more consistently by performing this inspiration when they are ready to. I’ve heard so many technologists yell to the patient, “Big breath in NOW!” when they want the patient to perform the initial inhalation to TLC. Why? There are some things the technologist must strictly control, but this is not one of them. The patient can be given control here, likely resulting in better patient performance with fewer trials needed.

By contrast, I almost always tell the patient when to begin the FEVC. I like to see a very short plateau (suggesting TLC has been attained) before telling them to blast it out. I find that telling the patient to “take a deep breath in and blast it out” may result in submaximal inspirations. There definitely should not be anything approaching a breath-hold before starting the maximal exhalation (this will usually decrease the PEFR and FEV1 and increase the back-extrapolated volume), but we do need to clearly see that they’ve reached TLC.

Not too sharp…

Occasionally I’ll find patients who have difficulty performing a good start-of-test; i.e., the start of the FEVC isn’t “sharp,” resulting in back-extrapolated volume errors. Sometimes these patients can perform the FEVC with much less back-extrapolated volume if they perform the initial inspiration to TLC and the FEVC in one motion, without any TLC plateau. I don’t like to have FVCs performed like this, because I really can’t be sure that they’re starting from TLC. But if 4-5 trials are performed like this with repeatable measurements, then I do feel confident that the measurements are accurate. Remember, reproducibility is our index of measurement accuracy, and sub-TLC FVCs seldom are reproducible.

You’ve gotta get it right.

Your instructions and demonstrations to the patient must be accurate. If your FEVC demonstration only lasts for 2-3 seconds, or if your demonstration doesn’t include a true maximal inhalation, or if you’re demonstrating the FEVC through pursed lips, or if you make a sound with your voice when maximally exhaling, or if you’re telling the patient to blast it out while he or she is still inhaling to TLC… and if your patient follows your instructions precisely… guess what kind of measurements you’ll get?

Maneuver instructions for our patients must be 100% accurate. Correct instruction and clear, concise feedback of maneuver performance is one of the technologist’s primary functions in a pulmonary lab. If the technologist is not instructing the maneuver correctly, how can our patients be expected to perform the maneuvers correctly?

Measurement conditions: very important!

I encourage everyone to become familiar with the concept of measurement conditions. These are the physiological conditions your instructions should create. The reason spirometry is performed is to assess the presence and degree of airway obstruction. This is best revealed when the patient suddenly, sharply contracts their costal muscles and diaphragm from TLC, and this is the measurement condition for FEVC.

The measurement condition for the SVC is a maximal but smooth, unforced exhalation. It should be smooth and slow enough that airway obstruction and air trapping are minimized.

Summarizing, we want to see the effect airway obstruction has on the FVC, and we do not want to see the effect airway obstruction has on the SVC. If you clearly understand when a specific measurement condition is required, and what that condition is, you’ll find that the best words to accurately instruct your patients will come quite easily.

Look at the shapes, not the prompts.

Learn to look at the shapes of the volume-time and flow-volume graphs instead of depending upon prompts from the computer software. The definition of a vital capacity is the maximum volume of air that can be exhaled from a maximal inhalation, or vice versa. If the ATS/ERS end-of-test prompt is displayed after 6.5 seconds, this does not necessarily mean the patient should start inhaling, especially if he or she is still moving air.

Here is another opportunity to give control to the patient; quickly keep repeating, “Keep going, keep pushing, when you absolutely can’t go any further take a fast deep breath in, keep going, keep pushing….” They’ve met end-of-test criteria but if they’re not empty, you haven’t measured a vital capacity. Give them permission to go as long as they can, and to inhale when they can’t go any further.

Really, it’s okay to do this; every ATS/ERS lung function recommendation states that these standards are intended to set minimum requirements, and they repeatedly encourage vendors and technologists to always try to exceed them. Bottom line, if they’re not empty, it’s not a VC.

In closing — it’s all in the details.

Much of what was covered here are the details of pulmonary testing. These details might be the difference between accurate pulmonary measurements and random numbers on a page. Although none of us get perfect tests on every patient, we should never settle for “close enough.” If your measurements do not meet the ATS/ERS or your department’s acceptability or repeatability criteria, post-test comments should be entered detailing which data are not reliable, and if possible, the direction of the inaccuracy. These comments are very important to the interpreting physician and all further reviewers.

I found it fascinating that such valuable discussion was raised by this post. I don’t know of any other source that covers everything discussed both in this article and in the post. These details are drawn from years of collective experience with thousands and thousands of patients. We’re fortunate to have the Diagnostics Section discussion list on AARConnect available as a vehicle for these discussions.


  • Miller MR, Hankinson J, Brusasco V, Burgos F, Cassaburi R, Coates A. et al. Standardisation of spirometry. Eur Respir J 2005;26(2):319-338.
  • Haynes JM. Expiratory reserve volume maneuver may be the preferred method for some patients during spirometry testing. Respir Care 2013;58(2):e14-e15.
  • Borg BM, Thompson BR. The measurement of lung volumes using body plethysmography: a comparison of methodologies. Respir Care 2012;57(7):1076-1083.
  • Graham BL. Pulmonary function standards: a work in progress. Respir Care 2012;57(7):1199-1200.
  • Torre-Bouscoulet L, Velázquez-Uncal M, et al. Spirometry quality in adults with very severe lung function impairment. Respir Care 2015;60(5):740-743.
  • Haynes JM. Quality assurance of the pulmonary function technologist. Respir Care 2012;57(1):114-126.
  • Giner J, Plaza V, Rigau J, Solá J, Bolíbar I, Sanchis J. Spirometric standards and patient characteristics: an exploratory study of factors affecting fulfillment in routine clinical practice. Respir Care 2014;59(12):1832-1837.
  • Hankinson JL, Eschenbacher B, Townsend M, Stocks J, Quanjer PH. Use of forced vital capacity and forced expiratory time in 1 second quality criteria for determining a valid test. Eur Respir J 2015;45:1283-1292.
  • Haynes JM. The American Thoracic Society/European Respiratory Society acceptability criteria for spirometry: asking too much or not enough? Respir Care 2015;60(5):e113-e114.

2018 CPT® Code Changes

Jennifer Weltz Horpedahl, BSRT, RRT, RRT-NPS, RPFT, AE-C

It is the new year, and that has brought some changes to Current Procedural Terminology (CPT) codes that impact the Diagnostics Section.

Pulmonary Stress Testing

CPT Code 94620 (Pulmonary stress testing, simple): This code has been deleted and replaced with the codes below –

CPT Code 94617 (Exercise test for bronchospasm, including pre- and post-bronchodilator spirometry, electrocardiographic recording(s) and pulse oximetry): This code should be used for procedures used to assess for exercise-induced bronchospasm.

CPT Code 94618 (Pulmonary stress testing, including measurements of heart rate, oximetry, and oxygen titration, when performed): This code should be used for simple pulmonary stress tests (e.g. 6-minute walk tests).

CPT Code 94621 (Cardiopulmonary exercise testing, including measurements of minute ventilation, CO2 production, O2 uptake, and electrocardiographic recordings): Wording for this CPT code has been updated to more clearly describe the cardiopulmonary exercise testing procedure.


CPT Code 31645 (Therapeutic aspiration of tracheobronchial tree, initial): This code should be used for initial therapeutic bronchoscopy procedures and in the outpatient setting. Wording that this code should be used for abscess drainage was removed from this code.

CPT Code 31646 (Therapeutic aspiration of tracheobronchial tree subsequent, same hospital stay): This code should be used when a procedure is repeated during the same hospital stay.

Section Connection

Recruit a new member: Know an AARC member who could benefit from section membership? Ask them to call AARC Customer Service at (972) 243-2272 to add section membership to their overall membership package

Section discussion list: Go to the Diagnostics Section on AARConnect to network with your fellow section members..

Next Bulletin deadline: Fall-Winter Issue: August 1, 2018