954563 A wound dressing (14) for an aspirated wound dressing system (10) is disclosed. The dressing has a wound interface region for contacting or facing a wound site (18), an aspiration port (22) for receiving suction for aspiration of wound exudate and a liquid permeable pressure barrier (24) disposed between the wound interface region and the aspiration port. The pressure barrier substantially prevents the application of negative pressure from the aspiration port to the wound interface region. There is at least one atmospheric vent (28) for equalizing with atmosphere the pressure at the wound interface region and a liquid sensor (30) for sensing liquid within the wound dressing for controlling application of suction by the aspiration unit. The sensor generates a signal that controls the operation of the aspiration unit (12) attached to the aspiration port so that the wound is only exposed to a negative pressure when there is liquid to collect.
