Stasis chamber

A stasis chamber was a machine used to keep its occupant sedated and alive.

The Tenth Doctor instructed Martha Jones to put him in a stasis chamber, minus 200 degrees, to freeze the invading system out of him. (TV: 42)

The Graske used stasis chambers to keep the original copies of their changelings. (NOTDWU: Attack of the Graske)

Elliot Northover was kept in a stasis chamber after he was taken by the Silurians. (TV: Cold Blood)