The Argyle™ Sentinel Seal™ chest drainage unit (CDU) is a dry suction CDU used to reestablish normal lung function. The CDU incorporates four chambers: a collection chamber for monitoring volume, rate, and nature of drainage; a water-seal chamber that acts as a one-way valve, as well as a window into the patient's pleural space; a patient assessment manometer which gives real-time negative pressure readings of the patient's pleural space; and a dry suction mechanical regulator to control suction and help re-expand the lung.