ABSTRACT
In 1926, H. L. Blumgart used radon gas milked from radiation tubes to study the effect of various pharmacological and physiological perturbations on the velocity of blood flow in humans. The formation of inert-gas hydrates in vivo has indeed been proposed as an explanation for the anesthetic properties of noble gases such as krypton and xenon. The behavior of the noble gases in vivo can most easily be understood in terms of their physical properties. These gases are highly diffusible with diffusion equilibria between inhaled gas and blood obtained in less than 1 sec. The ratio of the solubility of an inert gas in a particular tissue to its solubility in an equal volume of blood is defined as the tissuerblood partition coefficient. The use of radioactive gases presents special problems in terms of isotope handling, with the primary difficulty being one of containment.
