Dr. 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.
Introduction:
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.”
PFT Blog by Richard Johnston is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
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