First-line medical thoracoscopy for pleural infection: the SPIRIT randomised controlled feasibility trial

Pleural infection remains a significant clinical challenge, requiring hospitalisation, intravenous antibiotics and early chest drain insertion. Medical thoracoscopy (MT), a minimally invasive procedure used electively in the UK for malignant effusions, has demonstrated good outcomes when applied to acute pleural infection in retrospective case series. However, it has not been evaluated as a first-line intervention in the UK in a randomised controlled trial (RCT).

The Studying Pleuroscopy in Routine Pleural Infection Treatment (SPIRIT) trial assessed the feasibility of conducting a full-scale RCT comparing MT with chest drain insertion for acute pleural infection within UK National Health Service (NHS) hospitals.

SPIRIT was an open-label, randomised feasibility trial conducted across seven NHS centres between 2017 and 2019. Adults with suspected pleural infection were prescreened; eligible patients were randomised to either chest drain insertion (control) or MT (performed the same or following day) with 90-day follow-up. The primary outcome was feasibility, assessed through a composite of prescreen, screen and allocation failure rates. Secondary outcomes included inpatient-stay duration, mortality, radiological and microbiological outcomes, second-line interventions, patient-reported outcomes and adverse events.

Of 193 patients prescreened, 181 (93.8%) were excluded due to at least one criterion. Key factors included lack of MT deliverability (49.2%), a not truly infected effusion (45.1%) and contraindications to drainage or study involvement (44.0%). Consequently, the primary feasibility endpoint was not met. All 12 eligible patients were randomised with no attrition. MT lasted 15 min longer than drain insertion, but chest drains remained in situ over 3 days longer (p=0.17) with a longer hospital stay (p=0.57). Radiological improvement, microbiological yield and symptom scores were similar. Adverse events occurred in one control and three MT patients.

A full-scale RCT is not likely to be feasible in an NHS setting on the proposed protocol. Targeted recruitment from centres equipped for emergency MT may enhance feasibility.

ISRCTN98460319.