BACKGROUND: Managing pleural effusion and symptomatic ascites in palliative care is crucial for alleviating symptoms and significantly enhancing the quality of life (QoL) for affected patients. Choosing the appropriate treatment modality requires careful consideration of potential risks and benefits, as well as the patient's life expectancy. Tunnelled catheters offer a distinct advantage by allowing insertion in an outpatient setting, thereby reducing or avoiding hospitalization, maximizing time spent at home given the limited life expectancy, and necessitating fewer subsequent pleural procedures for symptom relief. This study protocol outlines a prospective, multicentre study aimed at gaining insights into QoL based on patients' palliative care outcomes. Additionally, it will evaluate the clinical use, safety, and performance of tunnelled catheters and drainage kits in the home environment. METHODS: The multicentre prospective study will be conducted across five sites specialized in thoracic surgery and palliative care in Germany and will include a total of 150 patients. Participants will be patients with pleural effusion or ascites requiring a tunnelled catheter. Each patient will be followed postoperatively for at least 6 months. The primary focus will be on patient-reported palliative care outcomes using the validated Palliative Care Outcome Scale (POS) questionnaire. The POS, designed to assess palliative care needs, consists of 10 questions that evaluate physical, emotional, psychological, and spiritual needs. Additionally, the study will record and evaluate the implantation of the tunnelled catheter, the use of the drainage kit, and monitor short- and long-term complications. DISCUSSION: The findings from this study will expand our understanding of patients' palliative care outcomes when using tunnelled catheters. Moreover, the results will provide deeper insights into the safety and clinical use of tunnelled catheters. TRIAL REGISTRATION: The study was registered at the German Clinical Trial Register (DRKS): DRKS00031242, at 23 March, 2023.