The PROMPT study is testing whether an early keyhole procedure called Medical Thoracoscopy, which lets doctors look inside the chest and remove infected fluid, works better than current standard treatment (medicines to break up thick fluid) for people with pleural infection. About 170 patients in several hospitals will be randomly assigned to one of the two treatments, and researchers will see which approach results in fewer additional procedures-such as another drain or surgery-within 30 days, as well as how quickly people recover and whether they experience any complications. Everyone in the study receives high-quality care, and the results will help doctors better understand which treatment gives patients the best chance of recovering quickly and safely

Pleural infection, also known as empyema or complicated parapneumonic effusion, occurs when infected fluid collects in the space between the lung and the chest wall. This condition can cause severe illness, requiring hospital admission for urgent treatment. Standard treatment usually involves antibiotics and the insertion of a chest tube to drain the infected fluid. In many cases, doctors also use medications called fibrinolytics (current gold standard treatment), which are delivered directly into the chest to help break up thick or separated pockets of fluid. While this treatment is effective for many people, around one-third of patients still do not fully recover with the initial approach and end up needing additional procedures or surgery. Because of this, doctors are looking for better ways to treat pleural infection earlier and more effectively.

One promising option is Medical Thoracoscopy, a minimally invasive procedure performed under local anaesthetic and conscious sedation. Through a small incision, doctors insert a camera into the chest to directly see and treat the infection. They can remove thick or loculated fluid, release adhesions, clean the pleural cavity more thoroughly, and place a larger drain under direct vision. Previous observational studies have suggested that performing thoracoscopy early in the illness may reduce the need for surgery later on. However, high-quality research comparing this approach with current standard care is still limited, and existing studies have faced challenges such as delays in timing and the use of surrogate outcomes rather than clinical ones. For this reason, more reliable evidence is needed to understand whether early Medical Thoracoscopy truly offers better results than fibrinolyitics.

The PROMPT trial ("Prospective study on the Role Of Medical thoracoscopy versus standard care in Pleural infecTion") has been designed to answer this important question. The study will take place across different hospitals in Italy, all of which have experience managing pleural disease and performing thoracoscopy. A total of 170 adult patients who are admitted to hospital with pleural infection and need drainage will be invited to take part. Everyone who agrees to join the study will be randomly allocated-like the flip of a coin-to receive either early Medical Thoracoscopy or standard care. This randomisation ensures that the comparison between treatments is fair, balanced, and unbiased.

Participants will be randomised either in the Medical Thoracoscopy arm or in the standard of care arm (fibrinolytics) within 24 hours after treatment failure of chest drain and medical therapy (i.e. antibiotics). In those who will be randomised in the Medical Thoracoscopy group, doctors will enter the chest cavity using a thin camera, break down any pockets of infected fluid, remove pus or debris, and place a chest drain. All patients will receive standard antibiotic treatment + chest drain placement recommended by current medical guidelines. Participants in the Standard Care group will receive fibrinolytic therapy (based on the well-established MIST-2 protocol). Urokinase may be used at centres where tPA and DNase are not routinely accessible. Both groups will receive the same supportive treatments, such as pain relief, physiotherapy, and oxygen if needed.

The main goal of the PROMPT trial is to determine whether early Medical Thoracoscopy reduces the need for additional procedures within the first 30 days. Additional procedures may include another chest drain, another course of fibrinolytics, or referral to surgery if the infection does not improve. The study is also interested in other important outcomes such as length of hospital stay, whether patients eventually require surgery, pain levels after treatment, side effects or complications, and survival up to 90 days. These outcomes are patient-centred and reflect the aspects of care that matter most to people facing this serious illness.

To ensure safety, all participants will be monitored carefully throughout their hospital stay and during follow-up visits at 30 and 90 days. A Data Monitoring Committee-independent of the research team-will regularly review safety information. If unexpected problems arise or if one treatment proves clearly superior or harmful, the committee has the authority to recommend changes or even stop the trial early. Ethical approval will be obtained before the trial begins, and all participants will provide written informed consent after receiving clear explanations of the study.

Every patient's personal information will be handled securely and confidentially according to European data protection regulations (GDPR). Only authorised members of the research team will have access to identifying information, and any data used for analysis will be anonymised. After the main results are published, the researchers plan to share anonymised datasets with other scientists who request access for further non-commercial research, helping to advance medical understanding while protecting participant privacy.

The PROMPT trial is expected to run for a total of 24 months, including recruitment and follow-up. No commercial funding is involved, ensuring that the study is entirely independent. Once completed, the research team will publish the results in peer-reviewed scientific journals, present them at conferences, and provide a plain-language summary so participants and the public can understand the findings.

Ultimately, the PROMPT study aims to provide clear, high-quality evidence about the best early treatment for pleural infection. If early Medical Thoracoscopy proves more effective than standard care, it could improve recovery, reduce the need for surgery, shorten hospital stays, and enhance the overall quality of care for patients facing this serious and often debilitating condition.

Inclusion criteria

• Adults ≥ 18 years
• Clinical and radiological diagnosis of pleural infection (purulent, culture-positive, or pH < 7.2)
• Need of pleural drainage
• Able and willing to give informed consent

Exclusion criteria

• Chest drain in situ >24h before randomisation
• Post-traumatic pleural effusion
• Known allergy to fibrinolytic agents or contraindication to thoracoscopy
• Pregnancy or breastfeeding
• Life expectancy < 3 months from another illness
• Previous lung surgery (pneumonectomy) in the same side of pleural infection
• Previous pleurodesis in the same side of pleural infection
• Any contraindication to Medical thoracoscopy