US Patent 8157792 Wound drainage suction relief

In accordance with one embodiment of the invention, there is provided a wound drainage system for draining fluid from a wound of a patient. The system includes a drain catheter. A suction means applies suction at the drain catheter such that fluid is drawn from the wound. While drawing fluid from the wound, a controller periodically increases and decreases the application of suction at the drain catheter. This allows the tissue surrounding the wound drain to relax, thus preventing obstruction of the drain catheter.