The Science of Hyperbaric Oxygen Therapy (HBOT)
Hyperbaric oxygen therapy, known as HBOT, is breathing 100% oxygen in a pressurised chamber.
Oxygen dissolves into red blood cells, plasma, lymph and cerebrospinal fluid. It floods damaged tissue with a level of oxygen not possible through breathing and normal circulation.
The physical gas laws we work with in HBOT
Boyle's Law regards shrinking of the physical bubble size.
States that at a constant temperature, gas volume is inversely proportional to pressure.
When pressure increases inside a hyperbaric chamber, gas spaces or bubbles in the body shrink in volume.
Henry's Law forces high concentrations of oxygen to dissolve directly into the blood plasma, flooding oxygen-starved tissue.
States that the amount of gas dissolved in a liquid is directly proportional to the partial pressure of that gas above the liquid.
High pressure inside the chamber forces significantly more oxygen to dissolve directly into the blood plasma, bypassing red blood cells.
Enhances oxygen delivery to oxygen-starved, hypoxic, or injured tissues to promote rapid healing
Charles’s Law shows that the increase in temperature has a direct effect on the volume of a gas, thus increasing the volume of available oxygen
States that gas volume is directly proportional to its absolute temperature when pressure remains constant.
This explains why the temperature inside a hyperbaric chamber rises during the initial compression (pressurization) phase.
The HBOT mechanisms
Pressure: free gas within the body is decreased in volume when under pressure
Hyperoxygenation: elevated pressure increases the amount of oxygen present in the blood.
Vasoconstriction: blood vessels narrow (vasoconstriction) as a result of the elevated oxygen levels. This results in reduced blood flow but doesn’t reduce tissue oxygenation, as a result oedema (tissue swelling) is reduced.
Angiogenesis: new micro blood vessels have growth promoted in previously oxygen deprived tissue (ischaemic tissue)
Bactericidal: production of certain toxins is slowed by the saturating of the tissue with oxygen. It is also effective in killing anaerobic bacteria. The effectiveness of white blood cells (leucocytes are responsible for killing bacteria) is increased by the increased tissue oxygen.
Anti-ischaemic: extra oxygen is physically dissolved into plasma (Henry’s Law in action).