A treatment device having: a pump, the pump having an inlet side and an outlet side, the pressure at the inlet side in use being lower than atmospheric pressure, the pressure at the outlet side in use being higher than atmospheric pressure; a breathing tube for connection to a patient; a pressure sensor adapted to measure the pressure within the breathing tube; a valve located between the pump and the breathing tube, the valve being adapted to selectively connect the breathing tube to the inlet side or the outlet side of the pump, the valve having a first valve inlet connected to the inlet side of the pump and a second valve inlet connected to the outlet side of the pump, the first valve inlet connected to a first valve inlet port and the second valve inlet connected to a second valve inlet port, the valve having a valve member with a valve opening, the valve member having a central opening connected to the valve opening, the central opening being connected to the breathing tube by way of a first valve outlet, the valve member being rotatable between a first operational position in which the valve opening overlaps the first valve inlet port and a second operational position in which the valve opening overlaps the second valve inlet port; a controller adapted to receive a pressure signal from the pressure sensor and to control the movement of the valve member, characterised in that the controller is adapted to determine the first operational position according to the overlap required between the valve opening and the first valve inlet port in order to provide a predetermined negative pressure within the breathing tube, and to determine the second operational position according to the overlap required between the valve opening and the second valve inlet port in order to provide a predetermined positive pressure within the breathing tube; and in that the treatment device has an indicator to indicate an operational status of the treatment device whereby the patient can synchronise his or her breathing with the device during use. a pump, the pump having an inlet side and an outlet side, the pressure at the inlet side in use being lower than atmospheric pressure, the pressure at the outlet side in use being higher than atmospheric pressure; a breathing tube for connection to a patient; a pressure sensor adapted to measure the pressure within the breathing tube; a valve located between the pump and the breathing tube, the valve being adapted to selectively connect the breathing tube to the inlet side or the outlet side of the pump, the valve having a first valve inlet connected to the inlet side of the pump and a second valve inlet connected to the outlet side of the pump, the first valve inlet connected to a first valve inlet port and the second valve inlet connected to a second valve inlet port, the valve having a valve member with a valve opening, the valve member having a central opening connected to the valve opening, the central opening being connected to the breathing tube by way of a first valve outlet, the valve member being rotatable between a first operational position in which the valve opening overlaps the first valve inlet port and a second operational position in which the valve opening overlaps the second valve inlet port; a controller adapted to receive a pressure signal from the pressure sensor and to control the movement of the valve member, characterised in that the controller is adapted to determine the first operational position according to the overlap required between the valve opening and the first valve inlet port in order to provide a predetermined negative pressure within the breathing tube, and to determine the second operational position according to the overlap required between the valve opening and the second valve inlet port in order to provide a predetermined positive pressure within the breathing tube; and in that the treatment device has an indicator to indicate an operational status of the treatment device whereby the patient can synchronise his or her breathing with the device during use.