Artificial pressure elevation has been around for decades.  It was first used to treat divers who were exposed to high pressure when submerged for long periods of time, resulting in a medical condition called the bends.  Later, hyperbaric pressure chambers (typically at 150% to 300% elevated pressure) were developed to treat individuals with mountain sickness and, even later, used to promote wound healing. Only over the past 15 years has hyperbarics been used to treat a variety of other medical disorders.