A feasibility randomised trial comparing therapeutic thoracentesis to chest tube insertion for the management of pleural infection: results from the ACTion trial

BACKGROUND

Pleural infection is a complex condition with a considerable healthcare burden. The average hospital stay for pleural infection is 14 days. Current standard of care defaults to chest tube insertion and intravenous antibiotics. There have been no randomised trials on the use of therapeutic thoracentesis (TT) for pleural fluid drainage in pleural infection.

AIMS AND OBJECTIVES

To assess the feasibility of a full-scale trial of chest tube vs TT for pleural infection in a single UK centre. The primary outcome was defined as the acceptability of randomisation to patients.

METHODS

Adult patients admitted with a pleural effusion felt to be related to infection and meeting criteria for drainage (based on international guidelines) were eligible for randomisation. Participants were randomised (1:1) to chest tube insertion or TT with daily review assessing need for further drainages or other therapies. Neither participant nor clinician were blinded to treatment allocation. Patients were followed up at 90 days post-randomisation.

RESULTS

From September 2019 to June 2021, 51 patients were diagnosed with pleural infection (complex parapneumonic effusion/empyema). Eleven patients met the inclusion criteria for trial and 10 patients were randomised (91%). The COVID-19 pandemic had a substantial impact on recruitment. Data completeness was high in both groups with no protocol deviations. Patients randomised to TT had a significantly shorter overall mean hospital stay (5.4 days, SD 5.1) compared to the chest tube control group (13 days, SD 6.0), p = 0.04. Total number of pleural procedures required per patient were similar, 1.2 in chest tube group and 1.4 in TT group. No patient required a surgical referral. Adverse events were similar between the groups with no readmissions related to pleural infection.

CONCLUSIONS

The ACTion trial met its pre-specified feasibility criteria for patient acceptability but other issues around feasibility of a full-scale trial remain. From the results available the hypothesis that TT can reduce length of stay in pleural infection should be explored further.

TRIAL REGISTRATION

ISRCTN: 84674413.

Management of Pleural Infection

Pleural infection is a millennia-spanning condition that has proved challenging to treat over many years. Fourteen percent of cases of pneumonia are reported to present with a pleural effusion on chest X-ray (CXR), which rises to 44% on ultrasound but many will resolve with prompt antibiotic therapy. To guide treatment, parapneumonic effusions have been separated into distinct categories according to their biochemical, microbiological and radiological characteristics. There is wide variation in causative organisms according to geographical location and healthcare setting. Positive cultures are only obtained in 56% of cases; therefore, empirical antibiotics should provide Gram-positive, Gram-negative and anaerobic cover whilst providing adequate pleural penetrance. With the advent of next-generation sequencing techniques, yields are expected to improve. Complicated parapneumonic effusions and empyema necessitate prompt tube thoracostomy. It is reported that 16-27% treated in this way will fail on this therapy and require some form of escalation. The now seminal Multi-centre Intrapleural Sepsis Trials (MIST) demonstrated the use of combination fibrinolysin and DNase as more effective in the treatment of empyema compared to either agent alone or placebo, and success rates of 90% are reported with this technique. The focus is now on dose adjustments according to the patient's specific 'fibrinolytic potential', in order to deliver personalised therapy. Surgery has remained a cornerstone in the management of pleural infection and is certainly required in late-stage manifestations of the disease. However, its role in early-stage disease and optimal patient selection is being re-explored. A number of adjunct and exploratory therapies are also discussed in this review, including the use of local anaesthetic thoracoscopy, indwelling pleural catheters, intrapleural antibiotics, pleural irrigation and steroid therapy.

Procalcitonin as preoperative marker for surgery in advanced parapneumonic empyema

BACKGROUND

The optimal time point for surgical management of advanced parapneumonic empyema in need of open pleurectomy and decortication remains unclear. We hypothesized that surgical outcomes will be better when procalcitonin (PCT) levels have dropped to normal ranges as evidence for resolution of the underlying pneumonia.

METHODS

We retrospectively analyzed outcomes of 38 patients with advanced parapneumonic empyema who underwent open decortication and pleurectomy with available preoperative PCT (pPCT) values. Patients were divided into two groups based on the pPCT cut-off of 0.25 µg/L. Total length of stay was the primary endpoint. Secondary endpoints included postoperative length of stay, surgery-related complications and death.

RESULTS

Patients with a pPCT ≥0.25 µg/L had a significantly longer total length of stay compared to patients with a pPCT level <0.25 µg/L [mean 22.4 vs. 15.0 days, difference -7.4 days (95% CI: -12.8 to -2.0), P=0.009]. This was also confirmed in linear regression analysis adjusting for age, gender and comorbidities [adjusted regression coefficient for log-transformed length of stay -0.27, 95% CI: -0.02 to -0.52, P=0.037]. Results for postoperative length of stay were similar. Eight patients in the pPCT ≥0.25 µg/L group had postoperative complications with two deaths while no complications occurred in the PCT <0.25 µg/L group (38% vs. 0%, P=0.004).

CONCLUSIONS

These data suggest better surgical outcomes in advanced parapneumonic empyema when pneumonia has resolved with a pPCT drop of <0.25 µg/L. A larger, prospective study is needed to confirm these results.