An implant for use in a human or animal body can include a flexible housing with an outer wall and having a chamber therein. The implant can have at least one high vapor pressure medium within the chamber. The at one high vapor pressure medium can have a combined vapor pressure equal to or greater than about the average value of the hydrostatic pressure of the implantation site plus the skin tension of the housing minus the gas tension of the dissolved gasses present at the implantation site.