Stop Air Leak by Talc or Autologous Blood Patch Therapy

Pneumothorax Spontaneous Secondary

Persistent air leak, talc pleurodesis, autologous blood patch therapy

Background: A pilot study to assess the feasibility of a randomisation trial protocol comparing intrapleural talc pleurodesis versus autologous blood patch therapy (ABPT) in patients with secondary spontaneous pneumothorax (SSP) complicated by persistent air leak (PAL). The proposed randomised protocol comparing talc pleurodesis and ABPT will be feasible and acceptable. Methods: A multi-centre, two-arm, open-label, randomised controlled feasibility study which includes subjects with SSP and PAL persisting for 5 days eligible for intrapleural therapy, with follow-ups till 3 months after hospital discharge. Recruited subjects will be randomised in 1:1 ratio to receive one dose of talc pleurodesis or ABPT. Discussion: The main outcome is the feasibility of the trial protocol, based on the percentage of eligible patients enrolled, retained to discharge, and completing 3 months of follow-up. Other important outcomes include complete cessation of air leak and successful chest drain removal within 3 days after the intervention, absolute and percentage changes in digitally measured air leak rates, duration of chest drainage, recurrence of ipsilateral pneumothorax, need for additional pleural interventions, safety outcomes such as drain blockage and pleural infection. Feasibility outcomes will be reported as descriptive data. Comparison of outcomes between the two treatment groups will be analysed on an intention-to-treat basis. Safety outcomes will be reported descriptively for each group. The reported estimates of recruitment rates, adherence, follow-up completeness, and variability and event rates for key clinical outcomes will be used, to inform sample size calculations for future studies incorporating the current study design.

Pneumothorax, defined as the presence of air in the pleural space, is a common respiratory emergency that often necessitates prolonged hospitalisation. In cases where pneumothorax occurs in the setting of underlying chronic lung diseases (secondary spontaneous pneumothorax, SSP), the clinical course is considerably more severe. SSP patients are typically more hypoxic, more likely to develop persistent air leak (PAL) (exceeding 5-7 days), and experience longer hospital stays with higher in-patient mortality compared to those with primary spontaneous pneumothorax (PSP). The management of SSP with PAL remains controversial despite its clinical significance. Numerous strategies, including chemical pleurodesis, autologous blood patch therapy (ABPT), implantation of endobronchial valves (EBV), and surgical pleurodesis, are employed in practice. However, many SSP patients are unsuitable for invasive procedures such as EBV placement or surgery, owing to their poor premorbid status. In this context, ABPT and chemical pleurodesis (often using talc) emerge as low-cost, bedside alternatives. Yet, current practices vary widely, and a lack of robust comparative evidence has left clinicians with no definitive guidance regarding the optimal management approach. Talc pleurodesis, involving the intrapleural instillation of sterile talc powder, is a commonly adopted treatment for SSP with PAL. Retrospective studies indicate that 37.2% to 44.5% of SSP patients undergo chemical pleurodesis, with talc being the predominant agent. Reported treatment success is around 70%, with a median drainage duration of 12 days post-procedure. Adverse events, most notably chest pain affecting roughly one-third of patients, are not uncommon, although more serious complications such as respiratory distress occur in only 1.6% of cases. Nonetheless, these findings are derived from studies with retrospective designs and variable methodologies, limiting firm conclusions on efficacy and safety. In contrast, ABPT has been proposed as a promising alternative for managing PAL. This technique involves the intrapleural instillation of autologous blood with the aim of sealing the air leak, initially developed for PAL in post-operative pneumothorax. Several small-scale retrospective and prospective studies have suggested that ABPT can achieve cessation in 26% to 91% of cases, with some reports showing 71.7% to 84.0% of patients experiencing complete resolution within five days. Moreover, ABPT appears safe for repeated administration, with adverse events reported at incidences ranging from 0% to 16%. However, the heterogeneous outcomes likely reflect differences in blood dosage, timing of intervention, number of administrations, and varying definitions of PAL among studies. Given the controversy and the limitations of existing evidence, a multicentre randomised controlled trial (RCT) comparing talc pleurodesis with ABPT is imperative. To achieve this, a pilot study is designed to rigorously address methodological weaknesses by standardising the timing of pleural interventions, employing a digital chest drain system for precise, quantitative measurement of air leak, and adopting unified criteria for treatment success.

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