A sedation device has a housing divided internally into a ventilator chamber and an associated evaporator chamber which overlap and are separated by a filter mounted between the chambers and forming a common gas-permeable dividing wall between the chambers. An inlet port is provided at one end of the ventilator chamber at a top of the housing for connection to a patient ventilator in use. An outlet port on the evaporator chamber can be connected via a breathing tube to a patient. An evaporator is mounted within the evaporator chamber for delivery of a volatile sedative into the evaporator chamber during use.
