Supersaturation by counterperfusion and diffusion of gases

induced under steady-state conditions when two inert gases are transmitted in opposite directions across any system com-prising a diffusion barrier adjacent to a zone of limited convec-tive capacity. This has many implications for bubble formation in vivo and can explain the occurrence of symptoms of de-compression sickness without decompression. air embolism; bubble formation; counterdiffusion; decompres-sion sickness; dental anesthesia; gaseous anesthesia WHEN A SLAB 0F A UNIFORM MEDIUM is exposed to one inert gas on one side and to a second inert gas on the other side, all at the ambient pressure, then the tension (partial pressure) gradient of one dissolved gas exactly reciprocates that of the other gas diffusing in the oppo-site direction. This results in saturation at all points and, moreover, applies under these steady-state condi