Surgical drainage device with automatic negative pressure relief system

摘要

A surgical underwater drainage device for draining fluids from the body of a patient which is provided with an automatic negative pressure relief system is disclosed. The underwater drainage device includes a collection chamber, an underwater seal chamber and/or its equivalent, and a suction control chamber. In one embodiment a negative pressure relief valve is normally closed and provides a bypass around the liquid seal and/or its equivalent of the underwater seal chamber. When excess negativity occurs in the collection chamber and/or the thoracotomy tube, the relief valve opens automatically to slowly relieve the excess negativity. The relief valve also prevents flow to the collection chamber and/or the thoracotomy tube when the pressure in the collection chamber is equal to or greater than a predetermined minimum below the pressure on the opposite side of the seal of the underwater seal chamber or its equivalent. In another embodiment of the invention, a small bore tube is connected between the suction control chamber. The bore of the tube provides an open passageway between the two chambers but it tends to equalize the degree of negativity in the two chambers over a period of time. Thus, excess negativity within the thoracotomy tube will be slowly relieved.