A chest drainage system includes a collection device and a fluid pathway configured to extend from the collection device to a patient. The fluid pathway has a proximal portion configured to extend proximally toward the patient and a distal portion configured to extend distally from the patient. The chest drainage system also includes a pressure source including an accumulator configured to selectively provide sub-atmospheric pressure to the distal portion of the fluid pathway and a valve configured to selectively relieve pressure in the proximal portion of the fluid pathway. The system is configured to open the valve and to introduce the sub-atmospheric pressure from the accumulator of the pressure source when a predetermined pressure differential is detected between the proximal and distal portions of the fluid pathway.