An apparatus for draining fluids, for example, from a chest or pleural cavity, includes a collection chamber for collecting fluids through an inlet port for entry of the fluids. Also included is a dry or waterless suction control chamber in fluid communication with the collection chamber for regulating the degree of vacuum imposed in the collection chamber. If desired, a seal chamber can also be provided between the dry suction control chamber and the collection chamber so as to prevent any ambient or atmospheric air from passing into the collection chamber. The suction control chamber has a first inlet which is coupled to a suction source and a second inlet communicates with the ambient. A waterless regulator is provided for regulating the degree of suction imposed in the collection chamber at a plurality of predetermined preset levels of suction. This regulator is positioned between the suction inlet and the ambient inlet. The suction control chamber also has at least a visual indicator disposed between the regulator and the suction inlet for providing immediate confirmation of proper operation of suction in the collection chamber.The present invention also includes a device for retaining tubing under compression so as to provide self-sealing capability of the tubing during sampling or injection procedures.