What is Henry's Law and how does it apply to hyperbaric medicine?

When a liquid is exposed to gas some of the particles dissolve in it. The number of molecules that dissolve are dependent on the mass of the liquid, the partial pressure of the gas, the solubility and the surface area of the contact. Oxygen is carried in the hemoglobin of red blood cells and only readily dissolves in small amounts. If the partial pressure of the oxygen is increased such as with hyperbaric therapy then more oxygen molecules will dissolve. This is also the case for other gases such as nitrogen which, as an inert gas, does not dissolve in the blood stream but accumulates in tissues until no more molecules are able to be absorbed at that pressure. Nitrogen can be forced out of the tissues more quickly by breathing in an oxygen enriched atmosphere.