A customer had emailed me the following statement regarding hyperbaric treatment and obtaining similar partial pressures of oxygen through different methods…
“I’ve been researching & trying to determine if there would be any difference between two different methods to obtain the same partial pressure.
Method 1: 1.0 bar partial pressure from 100% O2 at 1ata
Method 2: 1.0 bar partial pressure from 50% O2 at 2ata
I know hyperbaric can enable you to break the 1.0 bar ceiling (partial pressure), but is there any unique benefit from higher absolute pressure (hyperbaric) at the same partial pressure?”
Theoretically the math is the same in regards to the partial pressure of oxygen and the concentration gradient it will move along. Another simple example would be the comparison of hyperbaric treatment at 3.0 ata with 50% oxygen and hyperbaric oxygen therapy at 1.5 ata with 100% oxygen, both giving a partial pressure of oxygen, ppO2 = 1.5 ata. I have explained this countless times in the past and thought that the answer might best be addressed in the blog for others to view. (Note: I called the second example Hyperbaric Oxygen Therapy for you purest out there)
This is one of the problems I have with the classical definition of hyperbaric oxygen therapy (HBOT) stating 100% oxygen is necessary to achieve this. I have on many occasions heard so called “educated” persons tell me that hyperbaric chambers providing less than 100% oxygen to the patient aren’t providing hyperbaric oxygen therapy. Either they haven’t thought about what they are saying or they don’t realize that any increase in oxygen from either pressure or oxygen concentration increases the partial pressure and therefore the force of diffusion. Personally, I believe that these parties like to use there definitions to sell their potential customers on using a chamber with 100% oxygen over a competitor who uses a mask, hood system, or even air environment. Funny thing is that these same locations would probably be charging patients for 60 or 90 minutes of “hyperbaric oxygen therapy”; however, since it is common practice at pressures above 2.0 ata with 100% oxygen to take an air break in which the patient is switched to a breathing mixture of 21% air for 5 minutes to prevent oxygen toxicity, it would appear that they have only provided the patient 55 minutes of hyperbaric oxygen therapy and all of their patients should demand refunds for incomplete services. Maybe that seems a little harsh, but then again, I am not the one flaunting definitions with no purpose other than to secure a sale.
On a completely separate note, although the partial pressures of oxygen would be equal in the examples above, we would not be taking into account the physiological effects that pressure has on the body. Don’t get me wrong, this is not an attempt to make claims in regards to pressure on the physical body, rather a statement declaring we have more than one variable being applied to the body. Question.. What is one of the primary methods for controlling swelling with acute injuries? Answer… Pressure! Have you ever heard of the RICE Method? It stands for Rest, Ice, Compression, Elevation. Compression is pressure, in this case being used to help control edema and inflammation. Have you ever known anyone to complain about subtle drops in barometric pressure? I think most of us have! These small changes in pressure have demonstrated physiological effects; I know, I am one of those human barometers. Personally, I believe that the current “dogma” concerning hyperbaric therapy will not remain for another 50 years. If research with high pressure air environments in contrast with low pressure oxygen environments were conducted, I am sure we would see slightly different results out of the study populations. In short, the partial pressure of oxygen may be the same, but if the pressure exerted on the body is different, then you have a different treatment protocol combining separate treatment parameters. I will be interested to see what advances science brings over the next 100 years and how much of the medical dogma of today is overturned. People used to think the world was flat. We also used to believe that we could get disease out of people from bleeding it out. Therefore, I try not to get too hung up on what the “experts” have to say about medicine and science.
Similar to this post and worth a read if you found this interesting is…
PREDICTION VS. UNDERSTANDING, SCIENCE VS. TRENDS, HYPERBARIC, GRAVITY, AND THE GEOCENTRIC THEORY
and
WHAT IS A PARTIAL PRESSURE AND WHY DO I CARE IN REGARDS TO HYPERBARIC?
Greg Harris - Hyperbaric Warrior