[Pressure-volume analysis of wound suction drainage containers and suction capacity of drainage tubes]

Four low-vacuum systems and eight high-vacuum systems were examined with special reference to the pressure-volume relations. The maximum filling volume for adequate transport of wound secretion was determined for each type. The use of a synthetic wound fluid instead of water resulted in a smaller aspiration volume. Enlargement of the tube diameter resulted in a reduced initial vacuum for the low-vacuum systems, whereas the high-vacuum systems were not affected. Normal drain tubes were compared with "Ulm drains" and silicon tubes for suction capacity. The suction maximum of normal tubes and silicon tubes was located at the proximal holes of the perforated tubes. The "Ulm drain," with perforation diameter increasing continuously to the distal end of the tube, was found to exert suction even at the more distal part of the tube. It is estimated that this tube allows locally more balanced vacuum in the wound.