Inter-observer variation in image interpretation and the prognostic importance of non-expansile lung in malignant pleural effusion.

BACKGROUND AND OBJECTIVE: Non-expansile lung (NEL) frequently complicates management of malignant pleural effusion (MPE) and is an important factor in clinical practice and trials. NEL is frequently diagnosed on a single radiographic observation, but neither the inter-observer agreement of this approach nor the prognostic importance of NEL in MPE has been reported. METHODS: A multicentre retrospective cohort study was performed in two UK pleural centres. NEL was defined as <50% pleural re-apposition on post-drainage radiographs by primary and secondary assessors at each site. Inter-observer agreement was assessed by Cohen's kappa (κ). Kaplan-Meier methodology and multivariate Cox models were used to assess the prognostic impact of NEL versus no NEL and 'complete NEL' versus 'complete expansion', based on a single assessor's results from each site. RESULTS: NEL was identified by the primary assessor in 33 of 97 (34%) in Cohort 1 and 15 of 86 (17%) in Cohort 2. Inter-observer agreement between assessors was only fair-to-moderate (Cohort 1 κ: 0.38 (95% CI: 0.21-0.55), Cohort 2 κ: 0.51 (95% CI: 0.30-0.72)). In both cohorts, NEL was associated with shorter median overall survival (Cohort 1: 188 vs 371 days, Cohort 2: 192 vs 412 days). This prognostic association was independent in Cohort 1 (hazard ratio (HR): 2.19, 95% CI: 1.31-3.66) but not in Cohort 2 (HR: 1.42, 95% CI: 0.71-2.87). Survival was inferior in both cohorts in cases of complete NEL versus complete expansion. CONCLUSION: Radiographic NEL is common but inter-observer agreement is only fair-to-moderate. NEL is associated with adverse survival. These data do not support the use of single radiographic assessments to classify NEL.

Unexpandable lung from pleural disease.

Unexpandable lung is a common complication of malignant pleural effusions and inflammatory pleural diseases, such as pleural infection (e.g. empyema and complicated parapneumonic effusion) and noninfectious fibrinous pleuritis. Unexpandable lung due to pleural disease may be because of an active pleural process, and is referred to as malignant or inflammatory lung entrapment. An unexpandable lung may also be encountered in the setting of remote pleural inflammation resulting in a mature fibrous membrane overlying the visceral pleura preventing full expansion of the lung. This condition is termed trapped lung and may be understood as a form of defective healing of the pleural space. Trapped lung typically presents as a chronic, stable pleural effusion without evidence of active pleural disease. An unexpandable lung most often manifests itself as an inability of fully expanding the lung with pleural space drainage. Patients will either develop chest pain preventing complete drainage of the pleural space or develop a post-procedure pneumothorax. Pleural manometry and radiological imaging are useful in the assessment of an unexpandable lung. Pleural manometry can demonstrate abnormal lung expansion during drainage and imaging will demonstrate abnormal visceral pleural thickening found in trapped lung or malignant and inflammatory lung entrapment.

Successful Treatment of Pneumothorax in a Dog With Sterile Pleural Fibrosis Caused by Chylothorax.

A 2-year-old, 12 kg, intact male crossbreed dog was presented with respiratory distress, exercise intolerance, and gagging. Plain thoracic radiographs revealed severe pleural effusion. Although bilateral needle thoracocentesis and chest tube placement were performed, no re-expansion of the lung lobes occurred. Pleural effusion was of chylous quality and led to lung entrapment. Computer tomography revealed a highly atrophic and atelectatic right middle lung lobe. The remaining lung lobes were only expanded to ~40%. Visceral pleura and pericardium showed a heterogeneous thickening consistent with pleural fibrosis. Partial pericardiectomy with resection of the middle lung lobe through a right lateral thoracotomy was performed. Ligation of the thoracic duct and ablation of the cisterna chyli was achieved through a single paracostal approach. Histopathology revealed chronic-active proliferative beginning granulomatous pleuritis, fibrotic pericarditis, and partial coagulative necrosis with incomplete granulomatous sequestration in the resected middle lung lobe. Chylothorax resolved after surgical intervention. Active pleural effusion resolved, and lung entrapment changed to trapped lung disease. The remaining lung lobes re-expanded to ~80% over the following 6 days. The dog was discharged 10 days later. Mild to moderate pleural effusion of non-chylic quality was present during the following 4 months. Meloxicam was administered for 4 months because of its anti-fibrotic and anti-inflammatory properties. Fifteen months later, thoracic radiographs revealed full radiologic expansion of the lungs with persistent mild pleural fibrosis. To the authors' knowledge, this is the first case report of pneumothorax due pleural fibrosis caused by chylothorax in a dog with an excellent clinical outcome.

Pre-EDIT: A Randomized Feasibility Trial of Elastance-Directed Intrapleural Catheter or Talc Pleurodesis in Malignant Pleural Effusion.

BACKGROUND: Talc slurry pleurodesis (TSP) prevents recurrence of symptomatic malignant pleural effusion (MPE) in 71% to 78% patients. Nonexpansile lung (NEL) frequently accounts for TSP failure but is often occult predrainage, impairing selection of patients. NEL is associated with high pleural elastance (PEL), but technical limitations have hampered the development of PEL as a predictive NEL marker. We performed a single-center, randomized, controlled, open-label feasibility trial of EDIT (elastance-directed indwelling pleural catheter or TSP) management, using a novel digital manometer and a new definition of high PEL. METHODS: Patients with symptomatic MPE were randomized 1:1 between EDIT and standard care (TSP). EDIT involved PEL assessment during large-volume thoracentesis; patients with high PEL (maximum PEL sustained over 250 mL [MaxPEL250] ≥ 14.5 cm H2O/L) were allocated to immediately receive an indwelling pleural catheter; the remainder underwent immediate drain placement for TSP. The primary outcome measure was recruitment feasibility, defined a priori as 30 patients over 12 months. Secondary outcomes included safety, technical reliability, and the aspiration volume required to detect high PEL. The accuracy of the PEL definition for NEL was analyzed post hoc. RESULTS: Thirty-one patients were randomized (one allocation failure) over 12 months. PEL assessment (mean duration, 33 minutes) was successful in 13 of 15 patients (87%). No directly attributable serious adverse events occurred. High PEL was detected in seven of 13 patients (54%), associated with 100% sensitivity and 67% specificity for NEL, and was first detected at a median volume of 325 mL (range, 250-800 mL). CONCLUSIONS: A phase 3 trial testing the effect of EDIT management on symptomatic MPE recurrence following TSP is feasible. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT03319186; URL: www.clinicaltrials.gov.

Pleural manometry-historical background, rationale for use and methods of measurement.

Subatmospheric pleural pressure (Ppl), which is approximately -3 to -5 cmH2O at functional residual capacity (FRC) makes pleura a unique organ in the human body. The negative Ppl is critical for maintaining the lungs in a properly inflated state and for proper blood circulation within the thorax. Significant and sudden pleural pressure changes associated with major pleural pathologies, as well as therapeutic interventions may be associated with life-threatening complications. The pleural pressure may show two different values depending on the measurement method applied. These are called pleural liquid pressure and pleural surface pressure. It should also be realized that there are significant differences in pleural pressure distribution in pneumothorax and pleural effusion. In pneumothorax, the pressure is the same throughout the pleural space, while in pleural effusion there is a vertical gradient of approximately 1 cm H2O/cm in the pleural pressure associated with the hydrostatic pressure of the fluid column. Currently, two main methods of pleural pressure measurement are used: simple water manometers and electronic systems. The water manometers are conceptually simple, cheap and user-friendly but they only allow the estimation of the mean values of pleural pressure. The electronic systems for pleural pressure measurement are based on pressure transducers. Their major advantages include precise measurements of instantaneous pleural pressure and the ability to display and to store a large amount of data. The paper presents principles and details of pleural pressure measurement as well as the rationale for its use.

Pleural manometry in patients with pleural diseases - the usefulness in clinical practice.

Although pleural manometry is a relatively simple medical procedure it is only occasionally used to follow pleural pressure (Ppl) changes during a therapeutic thoracentesis and pneumothorax drainage. As some studies showed that pleural pressure monitoring might be associated with significant advantages, pleural manometry has been increasingly evaluated in the last decade. The major clinical applications of pleural pressure measurements include: the prevention of complications associated with large volume thoracentesis, diagnosis and differentiation between various types of an unexpandable lung and a possible prediction of the efficacy of chest tube drainage in patients with spontaneous pneumothorax. It is well known that the therapeutic thoracentesis might be complicated by cough, chest discomfort, and rarely, by a life threatening condition called reexpansion pulmonary edema (RPE). The serious adverse events of thoracentesis are related to pleural pressure drop rather than to the volume of removed pleural effusion. The use of pleural manometry during pleural fluid withdrawal enables the evaluation of the relationship between withdrawn pleural fluid volume, pleural pressure changes and procedure related complications. Pleural pressure measurement is also an important tool to study the different mechanism of pneumothorax complicating the thoracentesis. Pleural manometry is critical for measurement of pleural elastance, diagnosis of an unexpandable lung and differentiation between trapped lung and lung entrapment. This usually has significant clinical implications in terms of further management of patients with pleural effusion. The paper is a comprehensive review presenting different aspects of pleural pressure measurement in clinical practice.

Management of chronic empyema with unexpandable lung in poor surgical risk patients using an empyema tube.

OBJECTIVES: High preoperative risk precludes decortication and other surgical interventions in some patients with chronic empyema. We manage such patients by converting the chest tube into an "empyema tube," cutting the tube near the skin and securing the end with a sterile clip to allow for open pleural drainage. The patient is followed serially, and the tube gradually withdrawn based on radiological resolution and amount of drainage. METHODS: Between 2010 and 2014, patients with chronic empyema and unexpandable lung, deemed high-risk surgical candidates, had staged chest tube removal, and were included for the study. The volume of fluid drained, culture results, duration of drainage, functional status, and comorbidities were recorded. MEASUREMENTS AND RESULTS: Eight patients qualified. All had resolution of infection. The tube was removed after an average of 73.6 ± 49.73 (95% confidence interval [CI]) days. The mean duration of antibiotic treatment was 5.37 ± 1.04 (95% CI) weeks. None required surgery or experienced complications from an empyema tube. CONCLUSION: A strategy of empyema tube drainage with staged removal is an option in appropriately selected patients with chronic empyema, unexpandable lung, and poor surgical candidacy.