Density of decompression bubbles and competition for gas among bubbles, tissue, and blood.

We used numerical solutions of a system of equations to simulate gas exchanges of bubbles after a decompression, with particular attention to the effect of number of bubble formation sites per unit of tissue. If many bubbles grow, they deplete the excess dissolved gas in the tissue. The consequences are as follows: 1) the many individual bubbles do not become as large as they would if fewer were competing for gas; 2) more gas is evolved when there are many sites; 3) the bubbles are absorbed sooner than the bigger bubbles that grow with few sites; 4) after diffusion into many bubbles causes N2 partial pressure in the tissue to fall immediately to a low level, N2 partial pressure in the tissue and the exiting blood remain "clamped" to this low level because dissolved N2 removed by blood is replenished by diffusion out of the bubbles; and 5) as long as many bubbles persist, the long-term removal of inert gas from the total system (tissue plus bubbles) follows a straight-line time course rather than an exponential course.