This is a brief summary on HBOT pressures and how to decide which pressure is best for a particular indication.
More pressure and more oxygen are NOT always better
Neurologic indications are typically treated between 1.3 and 2.0 ATA and systemic indications between 2.0 and 3.0 ATA.
In some patients, starting at a more neurologic level because of overall foundational health status (including detox potential and overall inflammatory load) is best due to neuroinflammation.
The main studies looking to optimized blood flow to the brain and systemically were done in the 1970’s and it seems that 1.3 ATA to 2.0 ATA is more of a neurologic/CNS pressure whereas 2.0 ATA or greater is more of a systemic pressure. What this means is that you’ll see more blood flow to the brain at 1.3 to 2.0 than you will when you go deeper and vice/versa (when more blood flow systemically noted).
The reason that I think this happens (no studies, my opinion) is that we know the brain is more sensitive to oxygen and pressure—especially brains that are injured, inflammed, and already under more oxidative stress—- and that at some threshold (maybe around 2.0 for most people on average but even less so if the brain is super stressed), the oxidative stress that occurs in the brain with subsequent vasoconstriction occurring leads to an overall decrease in brain blood flow and thus diffusion outside of blood vessels to get into the tissue beds and oxygenate cells. There seems to be a sweet spot where more oxygen and pressure helps and too much has the opposite effect, like a bell curve. Or goldilox zone,. You get it! And there are a few studies that show this including one on patients w/traumatic brain injuries treated at deeper pressures who actually got worse when going deeper compared to the placebo group (STUDY).
In contrast, lower amounts of oxygen and pressure that are best for the brain do not push blood systemically and as you go deeper, you do this better. We also know that the deeper you go, the more bone marrow stem cells are released although I should mention that this may not be the case for the brain. Because if you remember, there are not only circulating stem cells pushed out from the bone marrow during HBOT but there are also the localized progenitor cells in tissues that also get stimulated to make mature cells in that particular tissue. So we think neurologic stem cells are probably stimulated to grow new cells at milder pressure.
One of the most prolific researches in this field of pressure differentials and probably the father of neurologic HBOT is Dr. Paul Harch. He along with Richard Neubauer in Florida, published the first studies on milder pressures for brain injury in the late 1990’s and early 2000’s and since then, hundreds of papers across the world have used the milder treatment pressures (1.3 ATA to 1.5 ATA most commonly) with profound effects on neurologic conditions that span from anoxic brain injured kids, to patient with strokes, Alzheimer's, and of course many more studies on TBI/concussion (both acute and chronic).
There is, however, some controversy here which stems from the dearth of overall data.
Can we dial in the pressure to be more precise?
One question that often comes up is “what is the best pressure for me”? Or said another way, we know there is a range for neurologic-focused pressures and there is a range for systemic but within that range, how can we know what is best?
Unfortunately, the answer is that most often we don’t. This is why in many of the protocols, we will often start at one pressure and if there is no improvement, dive to a different pressure and/or adding in more integrations (i.e. other therapies) to help.
When it comes to brain-focused protocols, there is often a threshold that once we reach when the healing starts to happen rapidly. This is not as evident with systemic protocols but there is some variation as well here too.
What I’ve found in a decade of practice isn’t the easy answer. Everyone is different. How well optimized (or sick) are they? What other therapies will they be doing (i.e. what are they doing before, during, and after HBOT)? Do they need a ramp up of pressure slowly? And how can we best test to see what the optimal pressure is (we think) but be willing to titrate up or down as needed through a treatment protocol and as the clinical course evolves. I do, however, usually stick to the ranges laid out above. 1.3 to 2.0 for neurologic issues and 2.0to 2.4 ATA for more systemic issues.
But with caveats, of course! Because I also realize that not everyone will have access to a medical grade chamber and I have seen people heal from more systemic injuries in mild units. If they do heal, the protocols are almost alway longer and they are often using other modalities that synergize with HBOT.
A good example is Jordan Hasay, one of my clients who is a marathon runner and Olympic athlete hopeful. She had an Achilles Tendon sprain that was supposed to heal In 4 to 6 weeks per her trainers and it instead healed in two weeks while she used a mild chamber alongside additional recovery tech before, during, and after.
The short answer: more oxygen isn’t better, necessarily. We need to find that goldilox zone where the amount of oxygen infused is optimal for the particular condition we are treating.