Decompression chamber
From Memory Alpha, the free Star Trek reference.
The decompression chamber is a standard-equipment chamber of Starfleet sickbays. It is designed to treat illnesses caused by decompression sickness, such as that suffered by crewmen exposed to explosive decompression and the vacuum of space.
The decompression chamber aboard the USS Enterprise saw other uses as well. In 2267, Khan Noonien Singh used the Enterprise 's decompression chamber to torture Captain James T. Kirk and attempt to induce the rest of the senior staff to join his cause. (TOS: "Space Seed")
In 2269, Doctor Leonard McCoy and Mr. Spock used the chamber on Mira Romaine to force the invading Zetarian entities from her body after they had possessed her. (TOS: "The Lights of Zetar")
