Saline lavage alone prolongs drainage compared with intrapleural enzyme therapy in pleural infection: the SCOPE randomised controlled trial

BACKGROUND: Intrapleural enzyme therapy (IET) is widely used for pleural infections, including complicated parapneumonic effusions and empyema; however, the role of saline lavage alone or in combination with IET remains uncertain. METHODS: The SCOPE trial was a two-centre, prospective, randomised superiority study designed to determine whether saline lavage alone or combined with IET was superior to IET alone in adults with pleural infection. Patients were randomised in a 1:1:1 ratio to saline lavage alone, saline lavage plus IET (urokinase and DNase) or IET alone. Patients and outcome assessors were blinded to the treatment allocation. The primary end-point was the duration of pleural drainage. Secondary end-points included radiographic resolution, need for additional interventions, length of hospital stay, mortality and adverse events. RESULTS: 89 patients were analysed in three groups (saline lavage, n=30; saline+IET, n=30; IET, n=29). Baseline characteristics were broadly similar across the groups. The median (interquartile range) drainage duration was longer with saline lavage alone (4.0 (3.0-6.75) days) than with IET alone (3.0 (2.0-4.0) days; p=0.01) or saline lavage plus IET (3.0 (3.0-3.75) days; p=0.01). No significant difference was observed between the two IET-containing regimens (p=0.24). Secondary outcomes showed no clear advantage for saline lavage alone or in combination with IET. CONCLUSIONS: In pleural infection, saline lavage alone results in a longer drainage duration than IET. In this small superiority trial, adding saline lavage to IET did not demonstrate a clinically meaningful advantage over IET alone.