A reduced pressure treatment system for treating a wound on a patient with reduced pressure, the system comprising: a foam manifold for positioning proximate to the wound; a drape for covering the manifold and a portion of epidermis of the patient to form a sealed space; a reduced-pressure interface for providing reduced pressure through the drape to the manifold; a reduced-pressure source; a first conduit for fluidly coupling the reduced-pressure source to the reduced-pressure interface; a second conduit having at least one sensing lumen and having a distal opening and a proximal opening; wherein the reduced-pressure interface comprises: a housing having a cavity wall portion that forms a cavity having a tissue-facing cavity opening, an attachment device coupled to the housing for coupling the housing to the drape, and a conduit port coupled to the cavity wall and having a conduit aperture for receiving the first conduit, wherein the housing is made of a semi-rigid material adapted to collapse when exposed to a pressure in the cavity that is less than a threshold pressure; wherein the first conduit and the second conduit each have a distal end and a proximal end; wherein the distal end of the first conduit extends through the conduit aperture into the cavity, the first conduit comprises at least one primary lumen for delivering reduced pressure, the primary lumen extends from the distal end to the proximal end of the first conduit; and the sensing lumen extends from the distal end to the proximal end of the second conduit, and wherein the sensing lumen has a distal opening that contacts the manifold. a foam manifold for positioning proximate to the wound; a drape for covering the manifold and a portion of epidermis of the patient to form a sealed space; a reduced-pressure interface for providing reduced pressure through the drape to the manifold; a reduced-pressure source; a first conduit for fluidly coupling the reduced-pressure source to the reduced-pressure interface; a second conduit having at least one sensing lumen and having a distal opening and a proximal opening; wherein the reduced-pressure interface comprises: a housing having a cavity wall portion that forms a cavity having a tissue-facing cavity opening, an attachment device coupled to the housing for coupling the housing to the drape, and a conduit port coupled to the cavity wall and having a conduit aperture for receiving the first conduit, wherein the housing is made of a semi-rigid material adapted to collapse when exposed to a pressure in the cavity that is less than a threshold pressure; a housing having a cavity wall portion that forms a cavity having a tissue-facing cavity opening, an attachment device coupled to the housing for coupling the housing to the drape, and a conduit port coupled to the cavity wall and having a conduit aperture for receiving the first conduit, wherein the housing is made of a semi-rigid material adapted to collapse when exposed to a pressure in the cavity that is less than a threshold pressure; wherein the first conduit and the second conduit each have a distal end and a proximal end; wherein the distal end of the first conduit extends through the conduit aperture into the cavity, the first conduit comprises at least one primary lumen for delivering reduced pressure, the primary lumen extends from the distal end to the proximal end of the first conduit; and the sensing lumen extends from the distal end to the proximal end of the second conduit, and wherein the sensing lumen has a distal opening that contacts the manifold.