Pleural effusion is the pathologic accumulation of body fluids in the chest cavity and can be classified as pulmonary edema and hemothorax. Pulmonary edema is usually caused by heart diseases, which account for a greater proportion. In the case of excess effusion volume (1000 –1500 mL), dyspnea occurs in patients, whereas purulent effusion may lead to infection. In general, pleural effusion drainage is performed via an inserted chest tube or a pigtail catheter under clinician suggestions. In clinical practice, current pleural effusion drainage has some concerns, such as (1) drainage volume estimation, (2) drainage volume and duration control, and (3) unplanned chest tube/catheter removal by the patients. Moreover, the rapid drainage of large pleural effusion volumes leads to reexpansion pulmonary edema (RPE), which can threaten the patient’s life. Hence, the current drainage system needs to monitor the heart rate or respiration rate. In this study, we intend to establish a smart drainage monitoring system that could improve the traditional drainage system functions, including (1) drainage volume and speed estimation, removal warning, and heart rate monitoring, and (2) its applications to drainage monitoring in both the thoracic cavity and the abdominal cavity. We expect that we can improve the function of the drainage monitoring system in terms of drainage volume, physiological signals, and safety confirmation.