Should biological quality control be replaced?

I’ve been thinking about quality control and quality improvement lately. Mostly this has been about how to go about determining whether the lab has a quality problem with testing and what statistics should be used for this purpose but I was reminded recently about an issue concerning biological quality control that came up a couple months ago on the AARC diagnostics forum. Specifically, one of the participants noted that some of their technicians had refused to perform biological QC on the basis that it violated their HIPAA rights to the privacy of their medical information. Further discussion noted that this was actually a correct interpretation of the HIPAA regulations and that no PFT lab can “force” its technicians to perform biological QC.

I will be the first to admit that I’d never thought about it this way, and I’ve been mulling it over ever since. I’ve performed PFT testing on myself both for formal biological QC and as a quick way to check the operation of a test system for decades but I never thought of my PFT results as being part of my medical information. That’s probably an indication of my own short-sightedness however, and I also realize that over the years I’ve run across a number of testing issues I’d taken for granted up until somebody pointed out a problem with them.

My attitude towards my PFT results may also be due to the fact that I don’t have any notable lung disease. My lab has had technicians who have been asthmatic however, and this has never been a factor in whether they were hired or not (other than not letting them perform methacholine challenges). They’ve usually performed bio-QC on themselves and at the time they seemed to regard it as a way to check on the status of their asthma. In retrospect however, I have to wonder if they were ever concerned that I would use their health status and test information against them in their annual evaluation, or even that the hospital would re-consider their employment because the costs of their health insurance might be higher. Although I don’t think the hospitals I’ve worked for ever thought along these lines, like it or not there are many businesses where this is a factor.

Yesterday I asked myself what would happen if all PFT labs were required to completely end biological quality control because of HIPAA requirements? It didn’t take a lot of thought to realize that there are a number of mechanical test simulators in the marketplace that could do quite well at replacing the biological part of quality control. As importantly, the more I’ve thought about it the more I’ve come to think that biological QC probably isn’t the right way to go about QC in the first place.

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PFTs on YouTube

A friend recently sent me the links to several YouTube videos on pulmonary function testing. I’ve spent some time off and on over the last year looking at YouTube videos and in particular I’ve been looking for ones that can be used as part of technician education. Maybe I’ve set the bar too high but all too often I’ve been disappointed and frustrated with what I’ve found. One reason for this is that many videos are aimed at other audiences than technicians (i.e. medical students, physicians, patients). Another reason is that too often only simple concepts are presented, often in rote fashion and often without good visual explanations (c’mon, these are videos after all, not podcasts). A final reason is that sometimes they’re outdated, misleading or just plain wrong.

Still, even the flawed videos can be useful. Sometimes this is because they occasionally explain some concepts well; sometimes despite being simplistic they present a good overview; and sometimes because their mistakes can serve as points for discussion. I’ve tried to select videos that have at least some potential for use in technician education.

John B. West Respiratory Physiology Lectures

Based primarily on his classic textbook, ‘Respiratory Physiology’ (which should be on everybody’s bookshelf). Not 100% perfect but this is what many of the other videos should aspire to be. Many complex concepts explained using simple examples. Lots of interesting pictures and illustrations. Should be part of every technician’s education.

  1. Structure and Function
  2. Ventilation
  3. Blood Gas Transport
  4. Acid-Base Balance
  5. Diffusion
  6. Pulmonary Blood Flow
  7. Pulmonary Gas Exchange, Part 1
  8. Pulmonary Gas Exchange, Part 2
  9. Mechanics of Breathing, Part 1
  10. Mechanics of Breathing, Part 2
  11. Control of Ventilation
  12. Defense Systems of the Lung
  13. Respiration under Stress
  14. Respiration at the Limit

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A couple weeks ago I was asked whether it was safe for a patient with an abdominal aortic aneurysm (AAA) to have pulmonary function testing. My first thought was that it was probably unsafe but after a moment or two of thought I realized that I hadn’t reviewed the subject for a long time. When I checked the 2005 ATS/ERS general testing guidelines (there are no contraindications in the 2005 spirometry guidelines) I found that AAA wasn’t mentioned at all. In fact, the only absolute contraindication mentioned was that patients with a recent myocardial infarction (<1 month) should not be tested. Some relative contraindications were mentioned:

  • chest or abdominal pain
  • oral or facial pain
  • stress incontinence
  • dementia or confusional state

and activities that should be avoided prior to testing include:

  • smoking within 1 hour of testing
  • consuming alcohol within 4 hours of testing
  • performing vigorous exercise within 30 minutes of testing
  • wearing clothing that restricts the chest or abdomen
  • eating a large meal with 2 hours of testing

but these were factors where test results were likely to be suboptimal and not actually contraindications.

This got me curious since I thought that pulmonary function testing was contraindicated for more conditions than just an MI. I reviewed the 1994 and and then the 1987 ATS statements on spirometry but again found no mention of contraindications. Ditto on the 1993 ERS statement on spirometry and lung volumes. Finally, in the 1996 AARC clinical guidelines for spirometry I found a much longer list of contraindications:

  • hemoptysis of unknown origin
  • pneumothorax
  • recent mycardial infarction
  • recent pulmonary embolus
  • thoracic, abdominal or cerebral aneuysms
  • recent eye surgery
  • presence of an acute disease process that might interfere with test performance (e.g. nausea, vomiting)
  • recent surgery of thorax or abdomen

So where did the AARC’s list of contraindications come from? And why is there such a discrepancy between the ATS/ERS and the AARC guidelines?

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CPT Codes

About a month or so ago I was corresponding with the manager of a small PFT lab and in response to one of their questions I had mentioned that there were no CPT codes for MIP/MEP. They responded with “what’s a CPT code?” so I guess this means that CPT codes aren’t as well known as I thought they were.

CPT stands for Current Procedural Terminology and is managed by the American Medical Association. CPT codes are a relatively universal way to classify and describe all medical tests and procedures. They are also used by all insurance companies for medical billing so one downside to this is if there isn’t a CPT code for a test or a procedure, you can’t bill for it. CPT codes also include conditions that limit performing (or at least billing for) some tests in various combinations and to some extent this drives the way PFT tests are ordered and performed.

The CPT codes are reviewed, revised and updated annually. There have been a number of additions and changes to PFT CPT codes during the last five to ten years, and I’d say that with a few notable exceptions, most current PFT testing is adequately covered by the CPT codes. The current PFT CPT codes are:

CPT: Description: Exclusions:
94010 Spirometry, including graphic record, total and timed vital capacity, expiratory flow measurement(s), with or without maximum voluntary ventilation. Do not report in conjunction with 94150, 94200, 94375, 94728.
94011 Measurement of spirometry forced expiratory flows in an infant or child through 2 years of age
94012 Measurement of spirometry forced expiratory flows, before and after bronchodilator, in an infant or child through 2 years of age.
94013 Measurement of lung volumes (i.e., functional residual capacity (FRC); forced vital capacity (FVC), and expiratory reserve volume (ERV) in an infant or child through 2 years of age.
94014 Patient-initiated spirometry recording per 30 day period of time; includes reinforced education, transmission of spirometry tracing, data capture, analysis of transmitted data, periodic recalibration and review and interpretation by a physician or other qualified health professional.
94015 [patient-initiated spirometry] recording (includes hook-up, reinforced education, data transmission, data capture, trend analysis, and periodic recalibration).
94016 [patient-initiated spirometry] review and interpretation only by a physician or other qualified health professional.
94060 Bronchodilator responsiveness, spirometry as in 94010, pre- and post-bronchodilator administration. Do not report in conjunction with 94150, 94200, 94375, 94728. For prolonged exercise test for bronchospasm with pre- and post-spirometry use 94620.
94070 Bronchspasm provocation evaluation, multiple spirometric determination s as in 94010, with administered agents (eg. antigen(s), cold air, methacholine).

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New Year’s Resolutions for a better PFT lab

It’s a tradition to come up with New Year’s resolution in order to improve ourselves. How about some resolutions to improve our labs?

1. Review and update the procedure manual

When was the last time you reviewed your procedure manual? Procedure manuals should be reviewed by the lab manager and medical director annually. It’s time to re-read the ATS/ERS guidelines and then review and update your procedure manual. Both your old staff and your new staff need to know what to do and how to do it. Your procedure manual is also going to be the first thing that anybody looks at if your lab is ever inspected.

2. Biological QC

Daily calibrations (and you’re doing daily calibrations and keeping a log of them, aren’t you?) are not enough to make sure our test systems are operating correctly. Regular (weekly, bi-weekly or monthly) biological quality control on ourselves with a Levey-Jennings chart is still the best way to do this. Don’t put it off. Biological QC is not an option; it’s a minimum requirement for any medical lab.
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Re-branding, re-imagining and re-defining ourselves

This idea originates, as far as I know, from Michael Sims, president and CEO of NspireHealth. I got it second hand and suspect that it is a small part of a larger presentation but this one point is worth discussing by itself. Specifically, we call the places we work “Pulmonary Function Laboratories” and this is at best an outdated and somewhat obscure term that doesn’t do much to make it clear what we do.

What’s wrong with calling it a Pulmonary Function Lab?

Well “Pulmonary” is okay since it’s a rather dignified and erudite term for the part of the body we’re primarily concerned with. “Function” however, is a somewhat vague or ambiguous term. The dictionary definition (or at least one of them since the other is mathematical) is “an activity or purpose natural to or intended for a person or thing”. That sort of applies to what we do but not with any particular precision or clarity.

I think that it’s the words “Lab” or “Laboratory” are the biggest problem since they conjure up images of Bunsen burners, test tubes and white-coated scientists engaged in research (the buzzing electrical arcs climbing up Jacobs’ Ladders and cries of “it’s alive!” are optional). The dictionary definition is “a room or building equipped for scientific experiments, research, or teaching, or for the manufacture of drugs or chemicals.” Not particularly specific to what we do and not necessarily a place you’d want to have any tests performed.

Michael Sim’s suggestion was that we re-brand our place of work by calling it “Pulmonary Diagnostic Services” instead. This is an unambiguous title that clearly identifies what we do. More than that, it gives us an opportunity to re-imagine and re-define exactly what it is we do.

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It doesn’t make any sense

For a variety of reasons my wife recently had a full panel of PFTs (spiro+BD, lung volumes, DLCO) at a different hospital than the one I work at. I went with her and was pleased to see the technician perform the tests pleasantly, competently and thoroughly. I was able to glance at the results as the testing proceeded so I had a fairly good idea what the overall picture looked like by the time she was done.

The difficulty came later when my wife asked me to print out her results so we could go over them together. Many hospitals and medical centers have websites that let patients email their doctor, review their appointments and access their medical test results. They go by a variety of names such as MyChart, MyHealth, Patient Gateway, PatientSite, PatientConnect etc., etc. My hospital first implemented something like this over a dozen years ago so I had thought that by now they were fairly universal but conversations with a couple of friends from around the country have let me know that this isn’t really the case.

Regardless of this, the hospital where my wife had her PFTs does have a website for patients and her PFT results showed up about a week later. When I went to look at them however, I was completely taken aback. Not because the results were wrong but because they were presented in a way that made them incredibly difficult to read and understand.

Here’s the report (and yes, this is exactly what it looked like on the patient website):

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State Licensure requirements for PFT Testing

There has been a fair amount of confusion about PFT lab staff licensure requirements. This information is not available on the AARC website, nor on any of the AARC state society websites. A month or so ago I reached out to all of the AARC state societies but received responses from only a handful of them. I was recently able to complete this research however, by visiting the websites of the remaining state licensing boards and state legislatures.

It turns out that the majority of states require licensure of PFT Lab staff, most often by requiring CRT or RRT credentials, occasionally by allowing CPFT and RPFT credentials and in a couple of cases, a state licensure exam. There were also a couple of cases where the regulations were so vaguely written that it wasn’t clear whether pulmonary function testing fell under the Respiratory Care practitioner scope of practice or not.

Anyway, based on state society feedback and my best interpretation of the relevant laws and regulations, the following list should be a reasonably accurate look at the licensure requirements for each state.

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What’s in a name?

My lab is in the final stages of a software update that will allow for electronic signing of our reports. This has been a long and slow process partly because the release date of the software got pushed back several times but mostly because a wide variety of different hospital departments and sub-departments have had to be involved.

In all the years that I’ve had computers in the pulmonary function lab I’ve never gone through a software update that was either as easy as expected or occurred within the original schedule. This includes the time when all we had was a single IBM PC/AT with a 40 megabyte hard drive, no network and the only people that cared we were going through an update was ourselves. Since we now have a dozen networked PCs located in two different building on-campus as well as three off-site locations using an IS-managed SQL server and HL7 interface I didn’t have any expectations for a speedy update and so far I have not been disappointed.

This time because the update revolves around electronic signing the hospital’s Health Information Management (HIM, i.e. Medical Records) department has been significantly involved. Among other things this has led to HIM reviewing all of our reports and requiring changes to bring them up to hospital standards. To some extent this make sense since, for example, they require that patient identification be exactly the same on all reports from all departments (same fields, same locations).

However, they also questioned some of the terminology used on our test reports. We’ve used the default test names that were in our report format editor (yes, we’re that lazy) and until they were brought to our attention I never really thought how odd some of them were. In particular, some of the terms used for the diffusing capacity didn’t make a lot of sense. For example, DLCO corrected for hemoglobin was DsbHb and DLCO/VA was reported as D/Vasbhb. To some extent I understand where these names came from but the reality is that they are in part holdovers from the past, in part they come from a need to keep names short so they fit in what space is usually available on reports, and in some cases they were probably created by programmers who hadn’t the slightest idea what the correct nomenclature should have been.

Note: Dsb likely comes from a time when you needed to differentiate between the results of different types of DLCO tests (steady-state and single-breath). Since there hasn’t been a test system built for at least 40 years that could perform a steady-state DLCO, the need to make this distinction is long since past.

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Filter FUD

A lab manager recently emailed me and asked my opinion about whether it was okay to use generic mouthpiece filters on their test systems. They had asked the same question of their equipment manufacturer and received the following statement (parts of which have been redacted by me):

“The [model number] PFT system was designed/tested/certified using the [manufacturer’s] filter. While other “off-label” filters may fit our devices, they have never been tested or approved for use by [the manufacturer]. The precision and accuracy of our devices could be compromised by using different type filters. It is our recommendation that you continue to use the [manufacturer’s] approved filters with your PFT equipment.”

Since I doubt the manufacturer has tested their equipment with any other mouthpiece filters than those they sell this is in some ways a true statement. Having said that, it is also a statement designed to sow fear, uncertainty and doubt (FUD) in the minds of their customers about a subject that is relatively straightforward.

The human respiratory tract is a potential source of particles in the 0.1 to 20 micron range, particularly when coughing but even to some extent during quiet breathing. Mouthpiece filters are barrier filters and intended to prevent these particles from getting into PFT equipment. Filter manufacturer’s claims are very similar and usually state a “Bacterial filtration efficiency: > 99.999% and Viral filtration efficiency: > 99.99%”. In one sense this statement is somewhat disingenuous because mouthpiece filters are not tested with bacteria or viruses (which have diameters as small as 0.03 microns) directly, but are instead tested with aerosols generated by a nebulizer.

A HEPA (High Efficiency Particle Absorption) filter is a true bacterial filter and to meet standards it must filter out 99.97% of all particles 0.3 microns or larger. Mouthpiece filters are not HEPA filters, partly because of cost but far more importantly because HEPA filters have a lot of resistance to air flow. A HEPA filter is a sieve mouthpiece with opening sizes that prevent particles above a specific size from passing through. Mouthpiece filters instead work by impaction and electrostatic attraction. Larger particles are captured by impacting or otherwise being intercepted by the filter fibers and the fibers usually also have an electrostatic charge that attracts smaller particles.

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