Autism HBOT: First Look
April 20, 2006 by Do'C 
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It’s no secret that many DAN! doctors (and probably non-DAN! doctors as well) are already recommending and selling low-pressure hyperbaric oxygen therapy as a potential autism treatment. Here’s an example of one such physician (not a board-certified developmental pediatrician, pediatrician, or neurologist for that matter) here in Phoenix.
Before you jump on the “Children With Oxygen-Deprived Brains” bandwagon and chase the claimed “healing power” of oxygen, there’s a lot worth looking into here.
- The underlying science
- Several clinical aspects
- The marketing of HBOT
Even at a very basic level, understanding hyperbaric medicine crosses several scientific fields: physics, human physiology, chemistry, and sometimes even meteorology, to name a few. I will attempt to examine as many of the related fields as I can, but this may take several posts. As a starting point, I think it’s important to point out that prior to last month, there were zero scientific studies specific to hyperbaric oxygen therapy and autism indexed at PubMed. The first one has just been published in the journal, Medical Hypotheses, and I’ve had the opportunity to read it in its entirety.
In my next post, I intend to examine this specific paper in much more detail. Specifically, I’ll go back and highlight some of the underlying science and physiology, and attempt to carefully explain the difference between traditional hyperbaric oxygen therapy and the kind used to support the hypothesis as a treatment for autism in this paper. It’s also important to note that just because it’s been hypothesized does not mean it’s been proven. It hasn’t. To my knowledge, there have been no published randomized controlled trials for low-pressure hyperbaric oxygen therapy as an autism treatment yet.
I had wanted to begin with a detailed look at this paper, but at the first read through, noticed something that needs clarification (so I can work with the facts). Specifically, the treatment pressure of 1.3 ATA (atmospheres absolute) stated in this paper seems unlikely, if not impossible, given the equipment used. So before going into this much further, I’ve requested clarification of the facts in the form of a request for published erratum from Medical Hypotheses.
It will be extremely important to have the facts about the actual treatment pressure, because all further calculations of partial gas pressures specific to understanding the effects on blood oxygen content will be derived from the treatment pressure.
Bruce G. Charlton
Editor-in-Chief
Medical Hypotheses
medicalhypotheses@elsevier.comDear Mr. Charlton,
I recently had the opportunity to read the paper entitled “Hyperbaric oxygen therapy may improve symptoms in autistic children”, by Daniel A. Rossignol and Lanier W. Rossignol, in press as a corrected proof in your Journal.
I am writing to point out that there likely exists a significant factual error in the paper. I would like to request that you consider publishing an erratum, after consultation with the authors.
In this paper, all references to pressure are in Atmospheres Absolute or “ATA”. Additionally, the specific type of ‘hyperbaric’ chamber was not disclosed in the methods section of the paper. I contacted Dr. Rossignol, and he provided the make and model information for the chamber used - an OxyHealth Vitaeris 320 (a portable Gamow Bag-type chamber, originally designed to treat altitude sickness). I also contacted a manufacturer’s sales representative who confirmed that this model is limited to 4.0 PSIG (pounds per square inch gauge) operating pressure. Due to the type of low pressure ‘hyperbaric’ chamber used, the study pressure reported of 1.3 ATA (particular to this case series) would have been extremely unlikely, if not impossible to achieve, under normal clinical conditions (on dry land, not contained within a second, larger pressurized ‘hyperbaric’ chamber, and not in the presence of extreme meteorological phenomenon during every session).
Standards for definition of atmospheric pressure were published in 1976 by the United States Committee on Extension to the Standard Atmosphere (COESA), representing 29 U.S. scientific and engineering organizations, and can be found in the book U.S. Standard Atmosphere, 1976 published by the U.S. Government Printing Office, Washington, D.C.
From this accepted standard, it can be derived that 1 ATA is equal to 14.696 PSI (pounds per square inch). This is an accepted average for the typical atmospheric pressure at Sea Level, although in absolute terms, according to the standard, 1 ATA always equals 14.696 PSI. A simple calculation, based on the maximum of 4 PSIG of the ‘hyperbaric’ chamber used, reveals that the maximum theoretical pressure is 18.696 PSI or 1.272 ATA if at Sea Level.
1.272 ATA does not equal 1.3 ATA. The 1.3 ATA terminology is a marketing term used in general reference to the OxyHealth product, however the OxyHealth technical literature does disclose the actual maximum operating pressure of 4 PSI. The stated 1.3 ATA absolute pressure in this paper is misleading, because it is a marketing term, rounded up for simplicity or impact. It likely does not reflect real Atmospheres Absolute. Also, if the ‘hyperbaric’ treatments relevant to this study were in fact conducted in Arrington, VA, that absolute pressure would be even less due to the likely altitude of at least 700ft. above Sea Level, and subsequent lower ambient atmospheric pressure. The actual ATA would have likely been closer to 1.247. If rounding to one decimal place were scientifically acceptable or warranted, the published pressure likely should have been 1.2 and not 1.3 ATA. Furthermore, stated pressures in absolute atmospheres for non-rigid ‘hyperbaric’ chambers would need to include corresponding location-specific meteorological data for the dates of treatment and indicated PSIG during treatment, otherwise this paper should have stated treatment pressure of “approximately 1.25 ATA” or “approximately 1.27 ATA” (if conducted at Sea Level), rather than asserting “1.3 Atmospheres Absolute”.
Does the difference between the likely reality of closer to 1.25 ATA and 1.30 ATA matter? In hyperbaric medicine it can matter. Partial pressure calculations made to interpret expected effect on arterial blood gases taken only from ATA must be converted to mmHg for proper understanding of conventional lab work. The difference between an increase of .25 ATA and .30 ATA is the difference between 190mmHg and 228mmHg, or that the former is only 83% of the latter.
Thus, you can see that this is not a minor error that can be ignored. I hope that you will investigate this further, contact the study authors and consider publishing an erratum.
Sincerely,
Dad Of Cameron
As soon as I have the facts about the actual treatment pressure used in this study, it’ll be time for a closer look at the paper itself. In the meantime, I’m soliciting suggestions for a non-scientific “nickname” for the device pictured at the top of the post.
(Special thanks to blogger Not Mercury and commenter: Jennifer for input and discussion about this paper).
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Comment by mike stanton — 21 April, 2006 @ 12:20 am
It looks a bit like Thomas the Tank Engine to me.
Comment by Not Mercury — 21 April, 2006 @ 8:45 am
Umm, what’s the orifice on the end for? Is that a glove box fitting so you can reach in and soothe your child if she/he feels under pressure. Get it because it’s a Freddy Mercury song and mm/Hg and the whole mercury tox thing…..ah, never mind….
I like “Deep Blue Something” but it’s no Breakfast at Tiffany’s
How about Wind-O-Bag-O (see cuz there’s 2 O’s = O2)
$20,000 horizontal Moon Walk?
Comment by Dad Of Cameron — 21 April, 2006 @ 9:11 am
Under Pressure - I like it.
Da da da da da da da da, Da da da da da da da da
“Pressure pushing down on me
Pressing down on you…”
Hyperbaric pressure
Financial pressure
Emotional pressure
Of course, if it’s not the Freddy Mercury, it could be some synergistic effect of all the band members.
Comment by Not Mercury — 21 April, 2006 @ 9:51 am
Wasn’t it a duet w/ David Bowie? Not quite as memorable as Little Drummer Boy with Bing Crosby or Dancing in the streets with Jagger……..Ah Ziggy, let’s just try to forget those years shall we.
Comment by Kassiane — 21 April, 2006 @ 10:38 am
Besides the study design being crap, altering blood gases is horrendously irresponsible.
It’s long been known that too much blood oxygen is a trigger for absence seizures. It’s also long been known that autistic people have a lower seizure threshold than NTs, since brain differences run in groups and all. If people aren’t with it enough to realize the kid is seizing when they can SEE them, how are they supposed to in the inflatable tube?
To me this looks like a real absence status epilepticus trigger. The people marketing these (or at least the ones they send to conferences) seem utterly clueless of this risk…a bit odd, if studies were actually done instead of pulling things out of thin air.
Comment by Prometheus — 21 April, 2006 @ 8:21 pm
DoC,
I thought that the port-o-chamber looked a bit…well, wimpy compared to the ones we had standing by when we were doing deep diving, so I checked in with a couple of centers that do real hyperbaric oxygen therapy. Here’s what I found:
[1] Normal, healthy divers breathing air are at increased risk of oxygen-induced seizures below 40 meters, which is equivalent to a total (absolute) pressure of 5 Atm. The partial pressure of oxygen (in air) at this point is 760 mm Hg (1 Atm).
[2] The pressure inside the port-o-chamber (at 4 psi overpressure) is - as you calculated - 1.3 Atm (1.272). At this pressure, the partial pressure of oxygen in “room air” would be a mere 200 mm Hg - well below the toxic level.
However, breathing pure oxygen at even this mild pressure puts the partial pressure of oxygen at 980 mm Hg, above the toxicity threshold for healthy people and probably well above the safe threshold for people who may be at an elevated risk of seizure.
In reality, it i s highly unlikely that any of the “practitioners” using the port-o-chamber are using the type of equipment (tight-fitting non-rebreathing mask at high flows) that would deliver 100% oxygen, so the risk is probably nil - as is the benefit.
[3] Real hyperbaric oxygen therapy (HBOT) is performed at 2 - 3 Atm with a trained physician present. The increased pressure and the increased oxygen content (supplied by mask) that increase the amount of oxygen dissolved in the blood to the point where it is significant compared to the amount of oxygen carried on the hemoglobin in the red blood cells.
Breathing room air (and with a normal hemoglobin level and function), the blood carries many times more oxygen than could be dissolved in the plasma because of the oxygen carried by hemoglobin.
In short, the toy HBOT port-o-chamber will sustain just enough pressure to be potentially dangerous without coming near the effective pressures needed to significantly enhance blood oxygen-carrying capacity.
Prometheus.
Comment by Dad Of Cameron — 21 April, 2006 @ 9:33 pm
Hi Kassiane, thanks for stopping by. I’m definitely going to get to some interesting marketing points in a future post. Thank you for mentioning seizure risk, we’re going to look at that more closely too.
Hi Prometheus, you touched on many points I plan to cover in detail in a future post. Interestingly, this particular study used low pressure and slightly enriched air that provide blood plasma O2 levels that are probably less than simple O2 therapy alone (NRB mask isn’t even required, nasal canula at 6lpm and a simple mask at 10lpm both beat this setup for increased plasma oxygenation without pseudo-hyperbarics at all - partial pressure is a wonderful thing). Of course I can’t imagine that would be profitable to sell regular O’s.
“Breathing room air (and with a normal hemoglobin level and function), the blood carries many times more oxygen than could be dissolved in the plasma because of the oxygen carried by hemoglobin.”
About 50-60 times as much in a pediatric patient without hyperbarics, and still about 3 times as much in a maximum hyperbaric environment (3ATA, 100% O2). About 20 times as much in the environment of this study. Hemoglobin really should get some sort of award, shouldn’t it?
“In short, the toy HBOT port-o-chamber will sustain just enough pressure to be potentially dangerous without coming near the effective pressures needed to significantly enhance blood oxygen-carrying capacity.”
I promise a closer look - after all, this type of chamber is in popular day spas and salons - there must be something to it. Oh wait, that would be a sarcastic appeal to popularity, I’d better stick to the science.
Speaking of science, and in case Dr. Rossignol happens to stop by for a read, I’d like to mention a couple of other things. First of all, there are some refreshingly honest disclosures and discussion in this paper - they don’t necessarily lend a lot of support to the study, but it is a hypothesis after all. I’m going to clearly point out those well-done disclosures for parents, because they are very important and would be missed if you only read the abstract. Secondly, there are two important points about the necessity for an erratum:
[1] Abosolutes are absolutes in scientific measurement standards. There is no valid scientific reason not to disclose the actual ATA instead of rounding up, especially when the issue is an attainable maximum. To do otherwise at this point, will skew further conversions to mmHg for partial pressure calculations. Any good scientist or physician should welcome the opportunity to have the most accurate information in their published work. Others will likely cite this paper in the future, it would be a shame if it contains inaccuracies that could impact validity of citations in future research. Now is the perfect time for them to get this right - from the get go.
[2] Decision by Medical Hypotheses not to request or publish an erratum would only serve to illustrate a possible true nature of the significance of pressures this low. If 1.25 or 1.27 and 1.30 ATA are not significantly different, then it just might be a demonstrable case that such pressures in this range in general could be insignificant in and of themselves.
Hopefully, Dr. Rossignol will espouse the “accuracy in the facts counts” position. His paper seems honest, and he was responsive to my request for additional information, so I’m optomistic.
Comment by Lanier Rossignol — 24 April, 2006 @ 7:32 pm
Dr. Rossignol and I have two autistic sons who have greatly benefited from the mild hbot in the chamber used in the study A pilot series was conducted to just see if further study was worthwhile. Further studies are being conducted currently and a large randomized placebo controlled study is planned. A fellow sceptic parent, Lanier Rossignol
Comment by Dad Of Cameron — 24 April, 2006 @ 8:27 pm
Ms. Rossignol,
I appreciate you taking the time to stop by and comment. I don’t question that anyone may have benefitted from participation in this study, however, use of parent-rated scales used to measure any benefits seem a little less than appropriate for a self proclaimed “skeptical” parent. The disclosures of limitations of this study, from small sample size and lack of control or blinding, to discussion about the possibility of natural development, or change as a result of other therapies despite the low-pressure hyperbarics were refreshingly, present. The hypothesis is valid (I’m not predicting proof or disproof in any way) - simply saying that is testable and falsifiable, so future studies will definitley shed a lot more light on the subject. Hopefully you are truly skeptical, and interested in the scientific accuracy and truth. Do you understand the ethical importance of correcting the overstated actual pressure in ATA?
P.S. I hope the whole family is doing very well.
Comment by Dad Of Cameron — 24 April, 2006 @ 9:06 pm
One medical question as well, Ms. Rossignol.
Being a Nurse Practioner, I’m assuming that you are very familiar with blood oxygen content calculations, Hüfner’s constant, the hemoglobin dissociation curve and all that stuff.
Surely you are aware that simple O2 therapy at 6lpm by nasal canula provides almost identical increase in plasma oxygen content as the hyperbaric 29% O2 air used in this study. Why go through all the hassle and expense (even for a study)?
Comment by Camille — 24 April, 2006 @ 9:24 pm
I personally am concerned with the issue of autistic children supposedly being harmed by oxidative stress and here it would seem that people are blithely popping autistic children into chamber that are bound to increase the “oxidative stress.” That’s beside the point that the machines are so expensive that it then becomes a lifestyles of the rich and famous kind of therapy. There may be some hucksterism here to sell these glorified toys (not by the Rossignols necessarily). And as Dad of Cameron pointed out, why bother? A nasal canula and pure O2 does the same trick. Making the whole toy HBOT thing look more like a scam.
Comment by Kev — 25 April, 2006 @ 2:48 am
Ms. Rossignol,
Thank you for taking the time to answer a few questions.
I’m curious to know - what lead you to publish your results in Medical Hypothesis? Wouldn’t a more ‘mainstream’ journal have been a better option for a study with the implications you claim for it?
Comment by Joseph — 25 April, 2006 @ 6:42 am
Ms. Rossignol,
Could you comment on the factual error brought up by Dad of Cameron, and on the need to publish errata?
Comment by Dr Gene Anthony — 9 May, 2006 @ 3:41 pm
One medical question as well, Ms. Rossignol.
Being a Nurse Practioner, I’m assuming that you are very familiar with blood oxygen content calculations, Hüfner’s constant, the hemoglobin dissociation curve and all that stuff.
Surely you are aware that simple O2 therapy at 6lpm by nasal canula provides almost identical increase in plasma oxygen content as the hyperbaric 29% O2 air used in this study. Why go through all the hassle and expense (even for a study)?
_______
I would like to know if any medical people or parents have tried using simple O2 therapy by nasal canula with ASD children. If they have, what kind of results have they experienced. Please feel free to contact me: drganthony@msn.com
Comment by Dad Of Cameron — 9 May, 2006 @ 4:56 pm
Dr. Anthony,
Hopefully you would prefer real peer-reviewed scientific research over reports of experience from parents via e-mail.
Comment by Ian — 10 May, 2006 @ 12:06 pm
The Vitaeris320 has a valve, to stop the pressure going too high. The chamber is rated to 6PSI, but the pressure valuve stops it going above approximately 4.3psi, which is 1.29 ATA at sea level
Comment by Dad Of Cameron — 10 May, 2006 @ 2:00 pm
Hi Ian.
Okay, so 1.29 ATM sounds fair, I did write in a later post that I was certainly nitpicking. All the documentation I reviewed for the Vitaeris states that there are two such pressure regulation valves, not one.
Comment by Dad Of Cameron — 10 May, 2006 @ 3:05 pm
All readers, please note that there was a follow-up to this post upon receipt of an additional e-mail from Dr. R.
Dr. R did confirm that the actual likely test pressure was ~1.285 ATM (apparently based on remebered observed pressure gauge readings of ~4.15 psi and historically typical atmospheric pressure for wherever this chamber was located. Follow-up appears in the additional post Nitpicking Sloppy Science Additional comment welcome at that post.