SDr. Paul Enright is a well-known name in the field of Pulmonary Function testing. He is the lead author or co-author of over a hundred articles and has served on many of the ATS/ERS standards committees.
We both retired in southern Arizona and live a couple of towns apart from each other. We have corresponded for a while but met face-to-face only recently. We both drive small red vehicles, Richard a Ford Transit Van and Paul a Prius Compact. We both love to visit National Parks; Richard’s favorite is Canyonlands while Paul’s favorite is Jasper, with many large wild animals. This posting is based on a set of suggestions by Paul.
In which hospital-based PFT labs have you worked?
Richard: St. Elizabeth’s then Beth Israel Deaconess Medical Center, both in Boston.
Paul: I started a very small PFT lab at the Kuakini Hospital in Honolulu; then the basement lab of the National Jewish Hospital in Denver, Colorado; then the Plummer Building of the Mayo Clinic in Rochester Minnesota; then the University Medical Center in Tucson, Arizona; then a NIOSH van running out of Morgantown, West Virginia.
Which is the largest PFT lab that you ever visited?
Richard: the PFT Lab at Mass General in Boston.
Paul: INER in Mexico City, where they test more than 10,000 patients per year. The medical director of the lab is my friend Laura G. One year a guard with a shotgun stood outside the lab because the payroll with bonuses for the institution was stolen the previous month (December).
Which PFT number should be removed from PFT reports?
Richard: FEF25-75 (aka MMEF) because it’s usually only abnormal when the FEV1 is abnormal (and because it has nothing to do with small airways).
Paul: DL/VA, because it is often normal in patients with interstitial lung disease.
Which PFT should be added to labs?
Richard: Possibly the Lung Clearance Index (LCI). Results are well characterized in a pediatric population and it may add something to the clinical monitoring of COPD.
Paul: Allergen skin prick tests. There are only six allergens which cause inflammation of airways in the lungs, thereby causing asthma exacerbations: cat, dog, mold, cockroach. and two types of house dust mites. Patients with asthma who are positive to one or more of these allergens can reduce the concentrations of these allergens in their home, thereby reducing their need for asthma medications.
Which are the three most important PFT numbers?
Richard: FEV1/FVC ratio, FEV1 and DLCO.
Paul: FEV1, FVC, and DLCO.
Which is the most expensive PFT instrument that most labs could do without?
Richard: Plethysmograph. Lung volume tests rarely add anything to the clinical picture.
Paul: Once you have spirometry, DLCO, and a chest x-ray results, body box tests (lung volumes and airway resistance) add no clinically useful information.
Which PFT is done with the worst accuracy?
Richard: Airway resistance (RAW and Sgaw).
Paul: Forced inspiratory flows which follow FVC maneuvers (aka flow-volume loops) are usually submaximal efforts. The false positive rate for upper airway obstruction is large, so most doctors just ignore the results.
What was the first spirometer you ever used?
Richard: Collins Modular Lung Analyzer equipped with Gaensler’s automated SB DLCO. The stainless steel spirometer bell was counterweighted with a chain and the kymograph pen was attached to the counterweight.
Paul: The McKesson Vitalor. It had a small rubber bellows which was rarely cleaned, so it probably transmitted tuberculosis from one patient to the next.
Which previously popular PFT was abandoned during your career?
Richard: Closing Volume. Popular for a while and thought to provide an early diagnosis for smoking-caused airway obstruction which has since proven not to be the case.
Paul: The maximal voluntary ventilation (MVV or MBC) test. It caused patients to hyperventilate, get dizzy, and fall off the chair.
What do you think of the forced oscillation tests?
Richard: Difficult to understand with inadequate clinical correlation.
Paul: After 65 years, they are still not ready for prime time (except perhaps for pre-school children with asthma symptoms who simply cannot perform FVC maneuvers).
What is the best PFT book for technologists?
Richard: Manual of Pulmonary Function Testing, originally edited by Greg Ruppel, now by Carl Mottram.
Paul: Lung Function Tests. Physiological Principals and Clinical Applications. Edited by JMB Hughes and NB Pride.
What’s wrong with the six minute walk test?
Richard: Finding a traffic-free corridor that’s long enough.
Paul: Many locations don’t have a 30 meter long corridor or hallway. Most pulse oximeters give falsely low SpO2s during the walk, due to motion artifact.
What is the most promising new PFT?
Richard: Although not a new test, possibly the LCI.
Paul: I don’t know any.
Who was your favorite PFT mentor?
Richard: Steve Weinberger.
Paul: Joe Rodarte (RIP) who always wore cowboy boots to work in Minnesota, was transfixed by young women, but moved to Houston, Texas.
What is your favorite spirometer?
Richard: Vitalograph Pneumotrac.
Paul: I have purchased hundreds of ndd EasyOnes for research studies.
What do you like about the new 2019 spirometry standards (guidelines)?
Richard: The distinction is finally made between test quality and test useability.
Paul: Quality grades for both FEV1 and FVC. These provide the doctor who ordered the test an indication of the degree of confidence that she should place in the numerical results.
Big Pharma buys more spirometers than anyone. Why?
Richard: Presumably for clinical trials although almost always low-end spirometers with limited accuracy.
Paul: Their only goal is to sell more COPD inhalers, which have been proven not to prolong life or reduce rapid decline in lung function caused by smoking.
Is it okay to stop FVC maneuvers after six seconds?
Richard: No. An FVC maneuver should go until no more air is coming out, regardless of whether this is less than or greater than 6 seconds. There is nothing magic about 6 seconds.
Paul: Only if they have reached a volume-time plateau or you are comparing the results with reference equations for the FEV1/FEV6.
What is the most clever device you have seen in a PFT lab?
Richard: Nothing comes to mind…
Paul: a target on the wall across from the patient. During FVC maneuvers, they are instructed to look at the target. This keeps their chin up. They can also be told to pretend that they are using a blow tube with a dart inside. This encourages a high peak flow.
What is the best way to minimize the risk of cross-contamination in a PFT lab?
Richard: Disposable mouthpieces and noseclips.
Paul: Wash your hands before and after testing each patient. Have plenty of space between the chairs in the waiting area.
What was the largest FVC you ever saw?
Richard: 8.6 liters in a 7 foot 2 inch tall male.
Paul: Ten liters. But in retrospect it was because the flow sensor had been clogged with phlegm.
Is it okay to only obtain one good DLCO maneuver?
Richard: No, although most of the time there is no significant difference they should be done at least twice to be sure.
Paul: That’s all they do in several large PFT labs. I once wanted to prove that this gave inaccurate results when compared to reporting the average of two good tests, but the results were only wrong about five percent of the time. Of course I didn’t publish that retrospective study.
In your experience, where is the worst quality spiromety performed?
Richard: Office spirometry with poorly trained staff.
Paul: By techs testing people previously exposed to asbestos in their workplace.
Who was your favorite PFT equipment salesperson?
Richard; Tom Carpenter, originally from Collins, then Ferraris and finally Nspire. Always cheerful and informative.
Paul: Jeurg Adenauer. We traveled to many countries together, using the EasyOnePro during workshops at annual meetings. The professional societies laundered the money for my travel. My last such meeting was in Bogota, Columbia.
What do you consider your biggest career success?
Richard: The PFT Blog.
Paul: Pulling Philip Quanjer (RIP) out of retirement to fight the faulty fixed ratio advertised by the GOLD guidelines. He then assembled an international group who developed the GLI equations.
Should primary care practitioners be encouraged to perform spirometry in their outpatient offices?
Richard: Office spirometry test quality is often poor but at least the physician is attempting to get an answer and questionable patients are usually referred to a hospital-based PFT Lab.
Paul: I wrote a book in 1987 called Office Spirometry. However, I now think that they should be able to order a spirometry test just like a CBC or chest x-ray, done quickly at a convenient location by certified technologists who are only paid for good quality tests (grade A or B). For example, vampires who work for Quest or LabCorp in the Untied States could have their quality verified centrally. First read the book “Bad Blood.”