difficult recruitment encountered during pandemic

Malignant pleural effusion (MPE) is a very common medical condition, especially among patients with disseminated cancers. Chest drain insertion aims to drain the pleural fluid collection and relieve dyspnea. Small bore chest tubes are recommended as the first line therapy for draining pleural effusions. However, there is no clinical data available to inform on the size of drains for better drainage. This is a randomized study comparing the two common bores of small bore chest drains in Hong Kong, and assess for its clinical efficacy and complication risks.

Introduction: Malignant pleural effusion (MPE) is the commonest complication of lung cancer, and its associated symptoms are frequent causes of hospitalizations and morbidities in patients with disseminated cancers. Chest tube drainage is often performed for symptomatic relief. Recent clinical trials had shown that large-bore chest drains (>14 French) caused significantly more pain than smaller drain during the insertion procedure and when the drain was in situ, which prompts the shift of preference towards smaller chest drains in guideline and clinical practice. Chest drains as small-bore as 7-8 French have been used in many local centers for drainage of MPE, though little attention has been made to the possible higher occurrence of drain blockage, kinking or dislodgement before optimal effusion drainage is achieved, which may lead to a second procedure for drain replacement. Currently, there is no data informing the efficacy and complications of ultra-small chest drains in clinical use. Therefore, it is imperative to call for further research on the optimal size of the chest drain which can achieve satisfactory drainage and at the same time, of minimal complications.

Study design: Single-center, parallel group, single blinded, randomized controlled study Study site: Department of Medicine, Queen Mary Hospital Target study participants: Subjects with symptomatic MPE requiring chest drainage

Method and analysis: This randomized controlled study to compare the efficacy of ultra-small bore chest drains (8 Fr) with standard small bore chest drain (14 French) as the reference. Primary outcome is drain success defined by nearly complete drainage of MPE on chest radiograph on day 5 of the drain. Other secondary outcomes include pain according to the visual analogue scale, dyspnea relief and complications during the procedure and post - chest drain insertion.

Inclusion Criteria:

• Patients who have cytologically/histologically proven pleural malignancy, or who have pleural effusion in the context of malignancy elsewhere
• The pleural effusion is at least moderate to massive and causes symptoms
• Ability to give informed written consent to the study

Exclusion Criteria:

• Age <18 years old
• Bleeding tendency not readily correctable (platelet < 100 x 10^9, INR ≥1.5 after transfusion)
• Hydropneumothorax before drain insertion
• Moderate-heavy septations in the pleural effusion (defined as a collection with more than 4 septations visible at the maximally septated area)
• Clinical emergency that an urgent chest drain is required
• Allergy to local anesthesia agents
• Blindness
• History of pleurodesis on the same side of malignant pleural effusion requiring drainage