An assembly used to promote wound healing through the creation of an oxygen gradient, whereby the oxygen gradient hastens the diffusion of oxygen from underlying capillaries and subcutaneous tissue up through and over an overlying target site of skin tissue. In an exemplary embodiment, the assembly provides a flush cycle and/or a negative pressure cycle to enhance the flow of oxygen from the subcutaneous tissue and the capillaries to the target site. In an exemplary embodiment, the assembly further comprises a means for maintaining a constant relative humidity over the wound site.