Systems and devices for treating a tissue site may include an interface adapted to provide a reduced pressure to a dressing. The interface may include a positive-pressure channel for delivering a positive pressure from a positive-pressure port to a positive pressure outlet. The positive-pressure channel may include a constricted portion configured to provide a pressure drop. The interface may additionally include a reduced-pressure channel adapted to deliver reduced pressure to the dressing that substantially corresponds to the pressure drop. The reduced-pressure channel may be fluidly coupled between the positive pressure channel and a side of the interface body adapted to face the dressing. Other systems and devices are disclosed.