Change in human blood plasma pH with pressure.

For the first time, the effect of hydrostatic pressure on the pH in human blood plasma was determined under well-defined conditions. By means of a colorimetric method the change in plasma pH was examined from 1 to 1,500 bar (atm). The change was -2.5 x 10(-4).bar-1, and it is then established that this effect is unimportant for physiologically tolerable pressures. A discussion of the gas-liquid equilibrium of CO2 is included, with a short consideration of the pressure effect on the hemoglobin system.