A wound treatment apparatus that ventilates a wound dressing with warm humidified oxygen and/or air at a very low flow rate while under a sub-atmospheric pressure. A controlled flow of filtered air and/or oxygen is selected or blended under atmospheric pressure. This gas is pulled by a downstream vacuum source through a flow limiting device and exits at a sub-atmospheric pressure equal to the vacuum source. The gas flow is then humidified and heated to prescribed conditions before entering a substantially airtight negative pressure type wound dressing which is adapted for ventilation with an added inlet connection. This conditioned gas ventilates and nourishes the wound environment exiting the dressing outlet, through a fluid trap, to the vacuum source.
