A subatmospheric pressure dressing can be readily applied by a single person and includes a flexible base which supports a gas permeable screen. A flexible sheet encloses the base and screen. The screen is connected with a source of low pressure (vacuum) by a suction tube. Transmittal of low fluid pressure causes the flexible sheet to be drawn into close contact with the screen to indicate that suction has been established. If a leak develops, the flexible sheet is no longer drawn to the screen to provide a clear indication of the leak.