Steroid Therapy and Outcome of Parapneumonic Pleural Effusions (STOPPE): A Pilot Randomized Clinical Trial.

Rationale: Pleural effusion commonly complicates community-acquired pneumonia and is associated with intense pleural inflammation. Whether antiinflammatory treatment with corticosteroids improves outcomes is unknown. Objectives: To assess the effects of corticosteroids in an adult population with pneumonia-related pleural effusion. Methods: The STOPPE (Steroid Therapy and Outcome of Parapneumonic Pleural Effusions) trial was a pilot, multicenter, double-blinded, placebo-controlled, randomized trial involving six Australian centers. Patients with community-acquired pneumonia and pleural effusion were randomized (2:1) to intravenous dexamethasone (4 mg twice daily for 48 h) or placebo and followed for 30 days. Given the diverse effects of corticosteroids, a comprehensive range of clinical, serological, and imaging outcomes were assessed in this pilot trial (ACTRN12618000947202). Measurements and Main Results: Eighty patients were randomized (one withdrawn before treatment) and received dexamethasone (n = 51) or placebo (n = 28). This pilot trial found no preliminary evidence of benefits of dexamethasone in improving time to sustained (>12 h) normalization of vital signs (temperature, oxygen saturations, blood pressure, heart, and respiratory rates): median, 41.0 (95% confidence interval, 32.3-54.5) versus 27.8 (15.4-49.5) hours in the placebo arm (hazard ratio, 0.729 [95% confidence interval, 0.453-1.173]; P = 0.193). Similarly, no differences in C-reactive protein or leukocyte counts were observed, except for a higher leukocyte count in the dexamethasone group at Day 3. Pleural drainage procedures were performed in 49.0% of dexamethasone-treated and 42.9% of placebo-treated patients (P = 0.60). Radiographic pleural opacification decreased over time with no consistent intergroup differences. Mean duration of antibiotic therapy (22.4 [SD, 15.4] vs. 20.4 [SD, 13.8] d) and median hospitalization (6.0 [interquartile range, 5.0-10.0] vs. 5.5 [interquartile range, 5.0-8.0] d) were similar between the dexamethasone and placebo groups. Serious adverse events occurred in 25.5% of dexamethasone-treated and 21.4% of placebo-treated patients. Transient hyperglycemia more commonly affected the dexamethasone group (15.6% vs. 7.1%). Conclusions: Systemic corticosteroids showed no preliminary benefits in adults with parapneumonic effusions. Clinical trial registered with www.anzctr.org.au (ACTRN12618000947202).

Alteplase Dose Assessment for Pleural infection Therapy (ADAPT) Study-2: Use of 2.5 mg alteplase as a starting intrapleural dose.

BACKGROUND AND OBJECTIVE: Intrapleural tissue plasminogen activator/deoxyribonuclease (tPA/DNase) therapy is increasingly used in pleural infection. Bleeding risks and costs associated with tPA remain the clinical concerns. Our dose de-escalation series aims to establish the lowest effective dosing regimen for tPA/DNase. This study assesses the intrapleural use of 2.5 mg tPA/5 mg DNase for pleural infection. METHODS: Consecutive patients with pleural infection treated with a starting regime of 2.5 mg tPA/5 mg DNase were included from two centres in Australia and UK. Escalation of tPA dose was permitted if clinical response was inadequate. RESULTS: Sixty-nine patients (mean age 61.0 years) received intrapleural 2.5 mg tPA/5 mg DNase. Most (88.4%) were treated successfully and discharged from hospital without surgery by 90 days. Patients received a median of 5 [interquartile range [IQR] = 3-6] doses of tPA/DNase. Total amount of tPA used per patient was 12.5 mg [median, IQR = 7.5-15.0]. Seventeen patients required dose escalation of tPA; most (n = 12) for attempted drainage of distant non-communicating locule(s). Treatment success was corroborated by clearance of pleural opacities on radiographs (from median 27.0% [IQR = 17.1-44.5] to 11.0% [IQR = 6.4-23.3] of hemithorax, p < 0.0001), increased pleural fluid drainage (1.98 L [median, IQR = 1.38-2.68] over 72 h following commencement of tPA/DNase) and reduction of serum C-reactive protein level (by 45.0% [IQR = 39.3-77.0] from baseline at day 5, p < 0.0001). Two patients required surgery. Six patients with significant comorbidities (e.g., advanced cancer) had ongoing infection when palliated and died. Two patients experienced self-limiting pleural bleeding and received blood transfusion. CONCLUSION: A starting intrapleural regime of 2.5 mg tPA/5 mg DNase, with up-titration if needed, can be effective and deserves further exploration.

Prospective validation of the RAPID clinical risk prediction score in adult patients with pleural infection: the PILOT study.

BACKGROUND: Over 30% of adult patients with pleural infection either die and/or require surgery. There is no robust means of predicting at baseline presentation which patients will suffer a poor clinical outcome. A validated risk prediction score would allow early identification of high-risk patients, potentially directing more aggressive treatment thereafter. OBJECTIVES: To prospectively assess a previously described risk score (the RAPID (Renal (urea), Age, fluid Purulence, Infection source, Dietary (albumin)) score) in adults with pleural infection. METHODS: Prospective observational cohort study that recruited patients undergoing treatment for pleural infection. RAPID score and risk category were calculated at baseline presentation. The primary outcome was mortality at 3 months; secondary outcomes were mortality at 12 months, length of hospital stay, need for thoracic surgery, failure of medical treatment and lung function at 3 months. RESULTS: Mortality data were available in 542 out of 546 patients recruited (99.3%). Overall mortality was 10% at 3 months (54 out of 542) and 19% at 12 months (102 out of 542). The RAPID risk category predicted mortality at 3 months. Low-risk mortality (RAPID score 0-2): five out of 222 (2.3%, 95% CI 0.9 to 5.7%); medium-risk mortality (RAPID score 3-4): 21 out of 228 (9.2%, 95% CI 6.0 to 13.7%); and high-risk mortality (RAPID score 5-7): 27 out of 92 (29.3%, 95% CI 21.0 to 39.2%). C-statistics for the scores at 3 months and 12 months were 0.78 (95% CI 0.71-0.83) and 0.77 (95% CI 0.72-0.82), respectively. CONCLUSIONS: The RAPID score stratifies adults with pleural infection according to increasing risk of mortality and should inform future research directed at improving outcomes in this patient population.

Bacteriology and clinical outcomes of patients with culture-positive pleural infection in Western Australia: A 6-year analysis.

BACKGROUND AND OBJECTIVE: Pleural infection is a clinical challenge; its microbiology can be complex. Epidemiological and outcome data of pleural infection in adult Australians are lacking. We describe the bacteriology and clinical outcomes of Australian adults with culture-positive pleural infection (CPPI) over a 6-year period. METHODS: Cases with CPPI were identified through Western Australian public hospitals electronic record. Culture isolates, admission dates, vital status, co-morbidities, radiology, blood and pleural fluid tests were extracted. RESULTS: In total, 601 cases (71.4% males; median age: 63 years (IQR: 50-74); median hospital stay 13 days) involving 894 bacterial isolates were identified. Hospital-acquired (HA)-CPPI was defined in 398 (66.2%) cases, community-acquired (CA)-CPPI in 164 (27.3%) cases and the remaining classified as oesophageal rupture/leak. Co-morbidities, most frequently cancer, were common (65.2%). Radiological evidence of pneumonia was present in only 43.8% of CA-CPPI and 27.3% of HA-CPPI. Of the 153 different bacterial strains cultured, Streptococcus species (32.9%) especially viridans streptococci group were most common in CA-CPPI, whereas HA-CPPI was most often associated with Staphylococcus aureus (11.6%) and Gram-negative (31.9%) infections. Mortality was high during hospitalization (CA-CPPI 13.4% vs HA-CPPI 16.6%; P = 0.417) and at 1 year (CA-CPPI 32.4% vs HA-CPPI 45.5%; P = 0.006). CONCLUSION: This is the first large multicentre epidemiological study of pleural infection in Australian adults and includes the largest cohort of HA-CPPI published to date. CPPI is caused by a diverse range of organisms which vary between CA and HA sources. CPPI is a poor prognostic indicator both in the short term and in the subsequent 12 months.

Pharmacokinetics of antibiotics for pleural infection.

INTRODUCTION: Pleural infection causes significant morbidity and mortality. An important aspect in the treatment of pleural infection is the pharmacokinetics of antibiotics, an area often neglected. AREAS COVERED: Pathophysiology of pleural infection and the importance of antibiotic therapy in the treatment of pleural infection are discussed. After reviewing all available literature on pharmacokinetics of antibiotics for pleural infection, the scarcity of data and knowledge gaps are highlighted. EXPERT OPINION: This review aims to heighten awareness of the limited pharmacokinetic data of commonly used antibiotics for pleural infection. It serves to remind clinicians that choice of antibiotics for pleural infection should be based not only on bacterial sensitivity but also adequate delivery of antibiotics to the infected pleural cavity. Antibiotic pharmacokinetics may vary with agents used, pleural thickness and individual characteristics. Consideration must be given to insufficient pleural delivery of systemic antibiotics in patients lacking clinical improvement. Pleural infection research has disproportionately focused on fluid drainage. Optimizing delivery of effective antibiotic therapy to the pleural cavity must be regarded a key priority to progress clinical care. Large comprehensive cohort studies on pharmacokinetic variability are the essential next step. The possibility of intrapleural administration is also an area that warrants additional research.

An international survey on the use of intrapleural tissue plasminogen activator/DNase therapy for pleural infection.

INTRODUCTION: Intrapleural tissue plasminogen activator (tPA) combined with human recombinant DNase (DNase) could be an effective alternative to surgery in managing pleural infection, as demonstrated in the Multi-centre Intrapleural Sepsis Trial (MIST)-2. However, the optimal delivery regimen is still unknown. The aim of this survey was to identify the current practice of tPA/DNase use by physicians with published interests in pleural infection, and their opinions on dose de-escalation of tPA/DNase therapy. METHODS: Potential participants were identified using four search strategies. Only practising physicians who were managing patients with pleural infections and either actively involved in pleural research and publications, or were members of relevant pleural disease guideline panels at the time of survey were included. RESULTS: An invitation email with the questionnaire was sent to 102 participants, of whom 49 (48%) responded. Most respondents (90%, n=44) have used tPA/DNase to manage pleural infection, but the dosing and delivery regimens employed varied. Many (86%, 38 out of 44) respondents have used 10 mg tPA, while 73% (n=32), 16% (n=7) and 9% (n=4) have used 5 mg, 2.5 mg and 1 mg doses, respectively. Most respondents instilled tPA/DNase concurrently (61%, n=27) and routinely administered six doses of tPA/DNase (52%, n=23) twice daily (82%, n=36). Respondents would consider using a lower starting dose of tPA (with the possibility of escalation if clinically needed) if a median 80% (interquartile range 50-80%) of patients could be successfully treated at that dose. CONCLUSION: This survey observed a large variation in the current treatment protocol of intrapleural tPA/DNase therapy worldwide and the need for more data on this subject.

Mepolizumab use in cystic fibrosis-associated allergic bronchopulmonary aspergillosis.

Allergic bronchopulmonary aspergillosis (ABPA) is common in cystic fibrosis (CF). Treatment is challenging and the relapse rate is high. Standard therapy is oral steroids and antifungals. However, long-term systemic steroid often results in adverse effects and drug interactions between azoles and CFTR modulators are a potential concern. Mepolizumab, an anti-interleukin (IL)-5 monoclonal antibody, can benefit patients with severe eosinophilic asthma and there are reports of mepolizumab use in ABPA but not in ABPA complicating CF. We present the case of an adult with CF who had recurrent ABPA and intolerable treatment side effects with steroid, azole, and omalizumab. Mepolizumab was well tolerated and led to significantly improved clinical stability and symptomatic improvement. To our knowledge, this is the first report of successful mepolizumab treatment for ABPA in CF. Mepolizumab may be an important adjunctive treatment for difficult to control ABPA in CF.

Neutrophil-to-lymphocyte ratio in malignant pleural fluid: Prognostic significance.

Predicting survival of patients with malignant pleural effusions (MPEs) is notoriously difficult. A robust prognostic marker can guide clinical decision making. The neutrophil-to-lymphocyte ratio (NLR) in blood has been shown to predict survival in many cancers. Pleural fluid bathes the malignant pleural tissues, thus the NLR of the pleural fluid may reflect more closely the local tumour environment. The objective of this study was to explore the prognostic significance of pleural effusion NLR for MPE. We analysed matched effusion and blood from 117 patients with malignant and 24 with benign pleural effusions. Those who had received recent chemotherapy or had a pleurodesis were excluded. Neutrophil and lymphocyte counts in effusions were performed by manual review of cytospin cell preparations by trained observers. Clinical data were extracted from a state-wide hospital database. We found significantly fewer neutrophils (expressed as percentage of total leukocyte count) in pleural fluid than in corresponding blood (9% vs 73%; p<0.001). The NLR was an order of magnitude lower in pleural fluid than in corresponding blood: median [IQR] = 0.20 [0.04-1.18] vs 4.9 [3.0-8.3], p<0.001. Correlation between blood and pleural fluid NLR in MPE patients was moderate (rs = 0.321, p<0.001). In univariate analysis, NLR (>0.745)) in malignant pleural fluid was predictive of poorer survival (HR = 1.698 [1.0054-2.736]; p = 0.030), and remained significant after adjustment for age, sex, presence of a chest drain, cancer type, concurrent infection and subsequent treatment with chemotherapy (HR = 1.786 [1.089-2.928]; p = 0.022). Patients with pleural fluid NLR > 0.745 had a significantly shorter median survival of 130 (95% CI 0-282) days compared to 312 (95% CI 195-428) days for pleural NLR < 0.745, p = 0.026. The NLR in blood was also predictive of poorer survival in MPE patients (HR = 1.959 [1.019-3.096]; p<0.001). The proportion of neutrophils in pleural fluid was predictive of prognosis more strongly than lymphocytes. This study provides evidence that NLR in malignant effusions can predict survival, and therefore may provide prognostic information for this cohort. This prognostic association in the fluid is driven by the presence of neutrophils.

Steroid therapy and outcome of parapneumonic pleural effusions (STOPPE): Study protocol for a multicenter, double-blinded, placebo-controlled randomized clinical trial.

BACKGROUND: Community-acquired pneumonia (CAP) is a major global disease. Parapneumonic effusions often complicate CAP and range from uninfected (simple) to infected (complicated) parapneumonic effusions and empyema (pus). CAP patients who have a pleural effusion at presentation are more likely to require hospitalization, have a longer length of stay and higher mortality than those without an effusion. Conventional management of pleural infection, with antibiotics and chest tube drainage, fails in about 30% of cases. Several randomized controlled trials (RCT) have evaluated the use of corticosteroids in CAP and demonstrated some potential benefits. Importantly, steroid use in pneumonia has an acceptable safety profile with no adverse impact on mortality. A RCT focused on pediatric patients with pneumonia and a parapneumonic effusion demonstrated shorter time to recovery. The effects of corticosteroid use on clinical outcomes in adults with parapneumonic effusions have not been tested. We hypothesize that parapneumonic effusions develop from an exaggerated pleural inflammatory response. Treatment with systemic steroids may dampen the inflammation and lead to improved clinical outcomes. The steroid therapy and outcome of parapneumonic pleural effusions (STOPPE) trial will assess the efficacy and safety of systemic corticosteroid as an adjunct therapy in adult patients with CAP and pleural effusions. METHODS: STOPPE is a pilot multicenter, double-blinded, placebo-controlled RCT that will randomize 80 patients with parapneumonic effusions (2:1) to intravenous dexamethasone or placebo, administered twice daily for 48 hours. This exploratory study will capture a wide range of clinically relevant endpoints which have been used in clinical trials of pneumonia and/or pleural infection; including, but not limited to: time to clinical stability, inflammatory markers, quality of life, length of hospital stay, proportion of patients requiring escalation of care (thoracostomy or thoracoscopy), and mortality. Safety will be assessed by monitoring for the incidence of adverse events during the study. DISCUSSION: STOPPE is the first trial to assess the efficacy and safety profile of systemic corticosteroids in adults with CAP and pleural effusions. This will inform future studies on feasibility and appropriate trial endpoints. TRIAL REGISTRATION: ACTRN12618000947202 PROTOCOL VERSION:: version 3.00/26.07.18.

A rapid, LC-MS/MS assay for quantification of piperacillin and tazobactam in human plasma and pleural fluid; application to a clinical pharmacokinetic study.

Piperacillin, in combination with tazobactam is a common first-line antibiotic used for the treatment of pleural infection, however its pleural pharmacokinetics and penetration has not previously been reported. The objective of this work was to develop and validate a rapid and sensitive liquid chromatography with tandem mass spectrometry (LC-MS/MS) assay for quantification of piperacillin (PIP) and tazobactam (TAZ). PIP and TAZ were extracted from both human plasma and pleural fluid samples by protein precipitation in methanol containing the internal standards (IS) piperacillin-d5 (PIP-d5) and sulbactam (SUL). Briefly, 5 µL of sample was mixed with 125 µL of methanol containing IS, vortexed and centrifuged. Supernatant (50 µL) was diluted into 500 µL of mobile phase containing 10 mM of ammonium bicarbonate in LCMS grade water and transferred to the autosampler tray. Electrospray ionization in positive mode and multiple reaction monitoring (MRM) were used for PIP and PIP-d5 at the transitions m/z 518.2 → 143.2 and m/z 523.2 → 148.2 respectively, and electrospray ionization in negative mode and MRM were used for TAZ and SUL at the transitions m/z 299.1 → 138.1 and m/z 232.4 → 140.1. The chromatographic separation was achieved using an Acquity BEH C-18 column with gradient elution of mobile phase containing 10 mmol/L ammonium bicarbonate in water and methanol. A linear range was observed over the concentration range of 0.25-352 mg/L and 0.25-50.5 mg/L for PIP and TAZ respectively. Complete method validation was performed according to US FDA guidelines for selectivity, specificity, precision and accuracy, LLOQ, matrix effects, recovery and stability, with all results within acceptable limits. This method was successfully applied to two patients with pleural infection and is suitable for further pharmacokinetic studies and therapeutic drug monitoring.

Streptococcus pneumoniae potently induces cell death in mesothelial cells.

Pleural infection/empyema is common and its incidence continues to rise. Streptococcus pneumoniae is the commonest bacterial cause of empyema in children and among the commonest in adults. The mesothelium represents the first line of defense against invading microorganisms, but mesothelial cell responses to common empyema pathogens, including S. pneumoniae, have seldom been studied. We assessed mesothelial cell viability in vitro following exposure to common empyema pathogens. Clinical isolates of S. pneumoniae from 25 patients with invasive pneumococcal disease and three reference strains were tested. All potently induced death of cultured mesothelial cells (MeT-5A) in a dose- and time-dependent manner (>90% at 107 CFU/mL after 24 hours). No significant mesothelial cell killing was observed when cells were co-cultured with Staphylococcus aureus, Streptococcus sanguinis and Streptococcus milleri group bacteria. S. pneumoniae induced mesothelial cell death via secretory product(s) as cytotoxicity could be: i) reproduced using conditioned media derived from S. pneumoniae and ii) in transwell studies when the bacteria and mesothelial cells were separated. No excess cell death was seen when heat-killed S. pneumoniae were used. Pneumolysin, a cytolytic S. pneumoniae toxin, induced cell death in a time- and dose-dependent manner. S. pneumoniae lacking the pneumolysin gene (D39 ΔPLY strain) failed to kill mesothelial cells compared to wild type (D39) controls, confirming the necessity of pneumolysin in D39-induced mesothelial cell death. However, pneumolysin gene mutation in other S. pneumoniae strains (TIGR4, ST3 and ST23F) only partly abolished their cytotoxic effects, suggesting different strains may induce cell death via different mechanisms.

Aggressive versus symptom-guided drainage of malignant pleural effusion via indwelling pleural catheters (AMPLE-2): an open-label randomised trial.

BACKGROUND: Indwelling pleural catheters are an established management option for malignant pleural effusion and have advantages over talc slurry pleurodesis. The optimal regimen of drainage after indwelling pleural catheter insertion is debated and ranges from aggressive (daily) drainage to drainage only when symptomatic. METHODS: AMPLE-2 was an open-label randomised trial involving 11 centres in Australia, New Zealand, Hong Kong, and Malaysia. Patients with symptomatic malignant pleural effusions were randomly assigned (1:1) to the aggressive (daily) or symptom-guided drainage groups for 60 days and minimised by cancer type (mesothelioma vs others), performance status (Eastern Cooperative Oncology Group [ECOG] score 0-1 vs ≥2), presence of trapped lung, and prior pleurodesis. Patients were followed up for 6 months. The primary outcome was mean daily breathlessness score, measured by use of a 100 mm visual analogue scale during the first 60 days. Secondary outcomes included rates of spontaneous pleurodesis and self-reported quality-of-life measures. Results were analysed by an intention-to-treat approach. This trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12615000963527. FINDINGS: Between July 20, 2015, and Jan 26, 2017, 87 patients were recruited and randomly assigned to the aggressive (n=43) or symptom-guided (n=44) drainage groups. The mean daily breathlessness scores did not differ significantly between the aggressive and symptom-guided drainage groups (geometric means 13·1 mm [95% CI 9·8-17·4] vs 17·3 mm [13·0-22·0]; ratio of geometric means 1·32 [95% CI 0·88-1·97]; p=0·18). More patients in the aggressive group developed spontaneous pleurodesis than in the symptom-guided group in the first 60 days (16 [37·2%] of 43 vs five [11·4%] of 44, p=0·0049) and at 6 months (19 [44·2%] vs seven [15·9%], p=0·004; hazard ratio 3·287 [95% CI 1·396-7·740]; p=0·0065). Patient-reported quality-of-life measures, assessed with EuroQoL-5 Dimensions-5 Levels (EQ-5D-5L), were better in the aggressive group than in the symptom-guided group (estimated means 0·713 [95% CI 0·647-0·779] vs 0·601 [0·536-0·667]). The estimated difference in means was 0·112 (95% CI 0·0198-0·204; p=0·0174). Pain scores, total days spent in hospital, and mortality did not differ significantly between groups. Serious adverse events occurred in 11 (25·6%) of 43 patients in the aggressive drainage group and in 12 (27·3%) of 44 patients in the symptom-guided drainage group, including 11 episodes of pleural infection in nine patients (five in the aggressive group and six in the symptom-guided drainage group). INTERPRETATION: We found no differences between the aggressive (daily) and the symptom-guided drainage regimens for indwelling pleural catheters in providing breathlessness control. These data indicate that daily indwelling pleural catheter drainage is more effective in promoting spontaneous pleurodesis and might improve quality of life. FUNDING: Cancer Council of Western Australia and the Sir Charles Gairdner Research Advisory Group.

Immediate effects of lumacaftor/ivacaftor administration on lung function in patients with severe cystic fibrosis lung disease.

Safety-data for lumacaftor/ivacaftor (LUM/IVA) combination therapy in patients with severe lung disease (percent predicted forced expiratory volume in 1s [ppFEV1] <40) remain limited. We report immediate post-dose respiratory-related adverse events in 12 patients with severe cystic fibrosis (CF) lung disease (median [IQR] ppFEV1: 34 [31-36]) prescribed LUM/IVA. All patients experienced a decline in ppFEV1 from baseline at 2-hours (median [IQR] relative change: -19 [-21 to -11]%, p<0.001) that persisted at 24-hours but recovered in most patients at 1-month. No pre- and post-differences in bronchodilator response were observed. Ten (83.3%) patients reported non-severe respiratory-related adverse events within 24-hours of LUM/IVA initiation. At 1-month, eight (67%) patients had persistent symptoms and six (50%) were treated for a pulmonary exacerbation. Our results highlight that LUM/IVA respiratory-related adverse events are common in patients with a ppFEV1<40. We recommend close assessment of adverse events. Further studies are required to evaluate the efficacy of LUM/IVA in patients with severe lung disease.

Dose De-escalation of Intrapleural Tissue Plasminogen Activator Therapy for Pleural Infection. The Alteplase Dose Assessment for Pleural Infection Therapy Project.

RATIONALE: Intrapleural therapy with a combination of tissue plasminogen activator (tPA) 10 mg and DNase 5 mg administered twice daily has been shown in randomized and open-label studies to successfully manage over 90% of patients with pleural infection without surgery. Potential bleeding risks associated with intrapleural tPA and its costs remain important concerns. The aim of the ongoing Alteplase Dose Assessment for Pleural infection Therapy (ADAPT) project is to investigate the efficacy and safety of dose de-escalation for intrapleural tPA. The first of several planned studies is presented here. OBJECTIVES: To evaluate the efficacy and safety of a reduced starting dose regimen of 5 mg of tPA with 5 mg of DNase administered intrapleurally for pleural infection. METHODS: Consecutive patients with pleural infection at four participating centers in Australia, the United Kingdom, and New Zealand were included in this observational, open-label study. Treatment was initiated with tPA 5 mg and DNase 5 mg twice daily. Subsequent dose escalation was permitted at the discretion of the attending physician. Data relating to treatment success, radiological and systemic inflammatory changes (blood C-reactive protein), volume of fluid drained, length of hospital stay, and treatment complications were extracted retrospectively from the medical records. RESULTS: We evaluated 61 patients (41 males; age, 57 ± 16 yr). Most patients (n = 58 [93.4%]) were successfully treated without requiring surgery for pleural infection. Treatment success was corroborated by clearance of pleural opacities visualized by chest radiography (from 42% [interquartile range, 22-58] to 16% [8-31] of hemithorax; P < 0.001), increase in pleural fluid drainage (from 175 ml in the 24 h preceding treatment to 2,025 ml [interquartile range, 1,247-2,984] over 72 h of therapy; P < 0.05) and a reduction in blood C-reactive protein (P < 0.05). Seven patients (11.5%) had dose escalation of tPA to 10 mg. Three patients underwent surgery. Three patients (4.9%) received blood transfusions for gradual pleural blood loss; none were hemodynamically compromised. Pain requiring escalation of analgesia affected 36% of patients; none required cessation of therapy. CONCLUSIONS: These pilot data suggest that a starting dose of 5 mg of tPA administered intrapleurally twice daily in combination with 5 mg of DNase for the treatment of pleural infection is safe and effective. This regimen should be tested in future randomized controlled trials.

Human pleural fluid is a potent growth medium for Streptococcus pneumoniae.

Empyema is defined by the presence of bacteria and/or pus in pleural effusions. However, the biology of bacteria within human pleural fluid has not been studied. Streptococcus pneumoniae is the most common cause of pediatric and frequent cause of adult empyema. We investigated whether S. pneumoniae can proliferate within human pleural fluid and if growth is affected by the cellular content of the fluid and/or characteristics of pneumococcal surface proteins. Invasive S. pneumoniae isolates (n = 24) and reference strain recovered from human blood or empyema were inoculated (1.5×106CFU/mL) into sterile human malignant pleural fluid samples (n = 11). All S. pneumoniae (n = 25) strains proliferated rapidly, increasing by a median of 3009 (IQR 1063-9846) from baseline at 24hrs in all pleural effusions tested. Proliferation was greater than in commercial pneumococcal culture media and concentrations were maintained for 48hrs without autolysis. A similar magnitude of proliferation was observed in pleural fluid before and after removal of its cellular content, p = 0.728. S. pneumoniae (D39 strain) wild-type, and derivatives (n = 12), each with mutation(s) in a different gene required for full virulence were inoculated into human pleural fluid (n = 8). S. pneumoniae with pneumococcal surface antigen A (ΔpsaA) mutation failed to grow (2207-fold lower than wild-type), p<0.001, however growth was restored with manganese supplementation. Growth of other common respiratory pathogens (n = 14) across pleural fluid samples (n = 7) was variable and inconsistent, with some strains failing to grow. We establish for the first time that pleural fluid is a potent growth medium for S. pneumoniae and proliferation is dependent on the PsaA surface protein and manganese.

Intrapleural tissue plasminogen activator and deoxyribonuclease therapy for pleural infection.

Pleural infection remains a global health burden associated with significant morbidity. Drainage of the infected pleural fluid is important but can often be hindered by septations and loculations. Intrapleural fibrinolytic therapy alone, to break pleural adhesions, has shown no convincing advantages over placebo in improving clinical outcome. Deoxyribonucleoprotein from degradation of leukocytes contributes significantly to high viscosity of infected pleural fluid. Recombinant deoxyribonuclease (DNase) is effective in reducing pleural fluid viscosity in pre-clinical studies. The combination of tissue plasminogen activator (tPA) and DNase was effective in animal model experiments of empyema. The benefits were established in a randomized clinical trial: those (n=48) treated with tPA/DNase had significantly improved radiological outcomes and reduced need of surgery and duration of hospital stay. A longitudinal observational series of 107 patients further confirmed the effectiveness and safety of tPA/DNase therapy, including its use as 'rescue therapy' when patients failed to respond to antibiotics and chest tube drainage. Overall, a short course of intrapleural tPA (10 mg) and DNase (5 mg) therapy provides a cure in over 90% of patients without requiring surgery. The treatment stimulates pleural fluid formation, enhances radiographic clearance and resolution of systemic inflammation. Serious complications are uncommon; pleural bleeding requiring transfusion occurred in ~2% of cases. Pain can occur, especially with the first dose. Treatment is contraindicated in those with significant bleeding diathesis or a bronchopleural fistula. Future research is required to optimize dosing regimens and in refining patient selection.