Abstract: A dressing for covering a wound of a patient comprises a sheet member adapted to be adhered to the patient's skin in use to provide an airtight seal around the wound, wherein the skin-adhesion is provided by a hydrogel layer 10 on the skin-facing face of the sheet member, wherein the sheet member defines in use a substantially enclosed space 5 above the wound, and wherein a plurality of mutually spaced-apart flutter valves formed by holes 5 in a thin film 13 overlying an upper face of a layer 12 of the sheet member permit one-way air, blood and/or other fluid flow communication from the space 5 above the wound to the exterior of the dressing.