Cardiopulmonary Exercise Test Methodology for Assessing Exertion Intolerance in ME/CFS, 2018, Stevens et al

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Sly Saint

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Cardiopulmonary Exercise Test Methodology for Assessing Exertion Intolerance in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Staci Stevens1, Chris Snell1, Jared Stevens1, Betsy keller2 and J. Mark VanNess3*
  • 1Workwell Foundation, United States
  • 2Department of Exercise & Sport Sciences, Ithaca College, United States
  • 3Health and Exercise Science, University of the Pacific, United States
Background: Concise methodological directions for administration of serial cardiopulmonary exercise testing (CPET) for is needed for testing of patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Maximal CPET is used to evaluate the coordinated muscular, metabolic, respiratory and cardiac contributions to energy production in patients with ME/CFS.

In this patient population, CPET also elicits a robust post-exertional symptom flare (termed, post-exertional malaise); a cardinal symptom of the disease. CPET measures are highly reliable and reproducible in both healthy and diseased populations. However, evidence to date indicates that ME/CFS patients are uniquely unable to reproduce CPET measures during a second test, despite giving maximal effort during both tests, due to the effects of PEM on energy production.

Results: To document and assess functional impairment due to the effects of post-exertional malaise in ME/CFS, a two-day CPET procedure (2-day CPET) has been used to first measure baseline functional capacity (CPET1) and provoke post-exertional malaise, then assess changes in CPET variables 24 hours later with a second CPET to assess the effects of post-exertional malaise on functional capacity. The second CPET measures changes in energy production and physiological function thus objectively documenting the effects of post-exertional malaise.

Use of CPET as a standardized stressor to induce post-exertional malaise and quantify impairment associated with post-exertional malaise has been employed to examine ME/CFS pathology in several studies. This article discusses the results of those studies, as well as the standardized techniques and procedures for use of the 2-day CPET in ME/CFS patients, and potentially other fatiguing illnesses.

Conclusions: Basic concepts of CPET are summarized, and special considerations for performing CPET on ME/CFS patients are detailed to ensure a valid outcome. The 2-day CPET methodology is outlined, and the utility of the procedure is discussed for assessment of functional capacity and exertion intolerance in ME/CFS.
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https://www.frontiersin.org/articles/10.3389/fped.2018.00242/abstract
 
I recently had a conversation with a family practice doctor (who has been in touch with Todd Davenport) about whether a CPET should be part of standard ME/CFS clinical care. His view was that it was not worth the risk to patients. I didn't disagree, except in cases where it was necessary to prove disability.
 
Webdog said:
I recently had a conversation with a family practice doctor (who has been in touch with Todd Davenport) about whether a CPET should be part of standard ME/CFS clinical care. His view was that it was not worth the risk to patients. I didn't disagree, except in cases where it was necessary to prove disability.
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Not sure patients should be pressured into an assessment that could make them permanently worse, just to satisfy a disability assessment.

I know I’d be too concerned about the harm this could cause me, to do it. :nailbiting:
 
Keela Too said:
Not sure patients should be pressured into an assessment that could make them permanently worse, just to satisfy a disability assessment.

I know I’d be too concerned about the harm this could cause me, to do it. :nailbiting:
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Agreed. But patients should perhaps be given the option of a CPET test if it's required to prove disability.

2-day CPETs are useful for researching PEM. But what is the benefit of a CPET in clinical care? Maybe to determine maximal heart rate? It's not clear that it's worth the risk for patients, and many (like you and me) would likely decline a CPET even if it were offered.
 
adambeyoncelowe said:
This is great. So how do we understand our results? I'm not sure the exercise physiology testing centre knew that much. All I know is that my VO2 max is the same as a person with COPD or MS, and just over half that expected for my age, which is bad.
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Can you share how your results changed between day 1 and 2? VO2, AT(anaerobic threshold)?
 
It's a really nice overview, especially to hand to someone who doesn't know much about it, although I'm a bit disappointed that they didn't include a table or graph which would summasire the changes that are most common in all studies and most specific for ME/CFS and how big those changes can be. Seems like a no brainer to me. I imagine someone who's not very familiar with CPER would be left a bit confused as to what exactly they should look for.
 
Pechius said:
It's a really nice overview, especially to hand to someone who doesn't know much about it, although I'm a bit disappointed that they didn't include a table or graph which would summasire the changes that are most common in all studies and most specific for ME/CFS and how big those changes can be. Seems like a no brainer to me. I imagine someone who's not very familiar with CPER would be left a bit confused as to what exactly they should look for.
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This manuscript is describing the practice protocol that they use and is not a systematic review of prior studies. The central replicated finding is a reduction of performance of patients at the ventilatory threshold on the second day. Other findings such as a reduction in VO2Max/VO2Peak on the second day have not been found in replication studies.
 
Keela Too said:
Not sure patients should be pressured into an assessment that could make them permanently worse, just to satisfy a disability assessment.

I know I’d be too concerned about the harm this could cause me, to do it. :nailbiting:
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Because validation is a very good thing, and having objective measure of disability matters a lot in disability insurance.

i totally understand the risks... until we have biomarkers and until we are established within mainstream medicine, at least some of us will have to prove disability through this mean.

Edit to add: at least some of us are not even believed by our own doctor, so providing them with a comprehensive assessement of the post exertional response may provide proof that of biological basis of symptoms and illness. (And yes, we are still at this stage in 2018)
 
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Snow Leopard said:
This manuscript is describing the practice protocol that they use and is not a systematic review of prior studies. The central replicated finding is a reduction of performance of patients at the ventilatory threshold on the second day. Other findings such as a reduction in VO2Max/VO2Peak on the second day have not been found in replication studies.
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Yes, but how much of a change? Should HR increase or decrease at AT/VT? Where do mild/moderate/severe patients fall?
 
Lucibee said:
Just noting that there are other threads of relevance on CPET (Is CPET safe for PwME; UK Locations that offer CPET testing), and wondering how they tie in with this study... (thinking aloud!).

Some are questioning the safety of CPET, and whether studies such as this will lead to them being inappropriately tested (for insurance, benefits, etc).

For example:

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I appreciate the concern that this could exacerbate a patient's condition. BUt I've also seen the 2 day CPET be the deciding factor in a positive decision on social security disability benefits (and thus medicare health insurance) in the US. Each patient needs to be aware of the risk and make a decision on the risk versus the benefit.
 
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