An Observational Study Evaluating the Performance of LENT Score in the Selected Population of Malignant Pleural Effusion from Lung Adenocarcinoma in Singapore.

BACKGROUND: Patients with malignant pleural effusion (MPE) secondary to lung cancer have been associated with poor prognosis historically. LENT score developed to risk-stratify unselected patients with MPE predicts prognosis of < 6 months in patients with lung cancer. OBJECTIVE: To assess the performance of LENT score in predicting prognosis in selected population of MPE secondary to lung adenocarcinoma alone. METHODS: A retrospective observational study was conducted by reviewing the medical records of patients managed for MPE in the year 2012. RESULTS: Seventy patients with lung adenocarcinoma presenting with MPE were studied. The median (range) LENT score at initial diagnosis was 5 (2-7), and the median survival 7.9 (0.13-40) months. Thirty-nine patients received epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKIs). The median LENT score and median survival was 4 (2-7) and 14.4 months, respectively, in this group. Those in high-risk category by LENT in this group (n = 19) had a median survival and 6-month survival of 17.4 months and 73.6%, respectively. Thirty-one patients were treated with conventional chemotherapy. The median LENT score and median survival was 5 (2-7) and 4.1 (0.13-34.3) months, respectively, in this group. The median survival and 6-month survival rate in patients in high-risk category and moderate-risk category by LENT score was 6.2 months and 52.7%, and 11.4 months and 70.5%, respectively. CONCLUSION: LENT score underestimates prognosis in patients having MPE secondary to lung adenocarcinoma. This disparity particularly applies to the lung adenocarcinoma patients carrying EGFR mutation. Hence, LENT score may not be applicable to, or may need modification before applying to such patients.

Randomized Trial of Pleural Fluid Drainage Frequency in Patients with Malignant Pleural Effusions. The ASAP Trial.

RATIONALE: Patients with malignant pleural effusions have significant dyspnea and shortened life expectancy. Indwelling pleural catheters allow patients to drain pleural fluid at home and can lead to autopleurodesis. The optimal drainage frequency to achieve autopleurodesis and freedom from catheter has not been determined. OBJECTIVES: To determine whether an aggressive daily drainage strategy is superior to the current standard every other day drainage of pleural fluid in achieving autopleurodesis. METHODS: Patients were randomized to either an aggressive drainage (daily drainage; n = 73) or standard drainage (every other day drainage; n = 76) of pleural fluid via a tunneled pleural catheter. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the incidence of autopleurodesis following the placement of the indwelling pleural catheters. The rate of autopleurodesis, defined as complete or partial response based on symptomatic and radiographic changes, was greater in the aggressive drainage arm than the standard drainage arm (47% vs. 24%, respectively; P = 0.003). Median time to autopleurodesis was shorter in the aggressive arm (54 d; 95% confidence interval, 34-83) as compared with the standard arm (90 d; 95% confidence interval, 70 to nonestimable). Rate of adverse events, quality of life, and patient satisfaction were not significantly different between the two arms. CONCLUSIONS: Among patients with malignant pleural effusion, daily drainage of pleural fluid via an indwelling pleural catheter led to a higher rate of autopleurodesis and faster time to liberty from catheter. Clinical trial registered with www.clinicaltrials.gov (NCT 00978939).

Management of parapneumonic effusion in pregnant women.

Pneumonia and parapneumonic effusion (PPE) are not more common in pregnant women compared to normal population. Pneumonia is considered the second most common infection in pregnant women. PPE is a serious complication of pneumonia and occurs especially in case of treatment delay or inappropriate antibiotic selection. The data on the management of PPE in pregnant women is limited to few case reports.

Computed tomography scoring system for discriminating between parapneumonic effusions eventually drained and those cured only with antibiotics.

BACKGROUND AND OBJECTIVE: Due to limited data, we aimed to develop and validate a computed tomography (CT)-based scoring system for identifying those parapneumonic effusions (PPEs) requiring drainage. METHODS: A retrospective review of all patients with PPE who underwent thoracentesis and a chest CT scan before any attempt to place a tube thoracostomy, if applicable, over an 8-year period was conducted. Eleven chest CT characteristics were compared between 90 patients with complicated PPEs (CPPEs), defined as those which eventually required chest drainage, and 60 with non-complicated effusions (derivation sample). A scoring system was devised with those CT findings identified as independent predictors of CPPE in a logistic regression analysis, and further validated in an independent population of 59 PPE patients. RESULTS: CT scores predicting CPPE were pleural contrast enhancement (3 points), pleural microbubbles, increased extrapleural fat attenuation and fluid volume ≥400 mL (1 point each). A sum score of ≥4 yielded 84% sensitivity (95% CI: 62-85%), 75% specificity (95% CI: 62-85%), 81% diagnostic accuracy (95% CI: 73-86%), likelihood ratio (LR) positive of 3.4 (95% CI: 2.1-5.4), LR negative of 0.22 (95% CI: 0.13-0.36) and area under the receiver operating characteristic curve (AUC) of 0.829 (95% CI: 0.754-0.904) for labelling CPPE in the derivation set. These results were reproduced in the validation sample. The CT grading scale also exhibited a fair ability to identify patients who needed surgery or would die from the pleural infection (AUC: 0.76, 95% CI: 0.61-0.9). CONCLUSION: A novel CT scoring system for adults with PPE may allow clinicians to predict the need for chest tube drainage with good accuracy.

Clinical features and survival of lung cancer patients with pleural effusions.

BACKGROUND AND OBJECTIVE: The clinical relevance of pleural effusions in lung cancer has seldom been approached systematically. The aim of this study was to determine the prevalence, causes and natural history of lung cancer-associated pleural effusions, as well as their influence on survival. METHODS: Retrospective review of clinical records and imaging of 556 consecutive patients with a newly diagnosed lung cancer over a 4-year period at our institution. RESULTS: Lung cancer comprised 490 non-small cell and 66 small cell types. About 40% of patients with lung cancer developed pleural effusions at some time during the course of their disease. In half the patients, the effusions were too small to be tapped. These effusions did not progress to require a pleural intervention. Patients with minimal effusions had a worse prognosis compared to patients without pleural effusions (median survival of 7.49 vs 12.65 months, P < 0.001). Less than 20% of the 113 patients subjected to a diagnostic thoracentesis had benign causes for their effusions. Palliative pleural procedures (like therapeutic thoracenteses, pleurodesis or tunnelled pleural catheters) were conducted in 79 (84%) of the 94 malignant effusions. An effusion's size equal to or greater than half of the hemithorax was a strong predictor of the need for a palliative procedure. Overall survival of patients with malignant effusions was 5.49 months. CONCLUSIONS: Malignant pleural effusions are a poor prognostic factor in the setting of lung cancer, which includes minimal effusions not amenable to tapping.

Comparison of pleural N-terminal pro-B-type natriuretic peptide, midregion pro-atrial natriuretic peptide and mid-region pro-adrenomedullin for the diagnosis of pleural effusions associated with cardiac failure.

BACKGROUND AND OBJECTIVE: The purpose of this study was to compare the diagnostic utility of pleural fluid N-terminal pro-B-type natriuretic peptide (NT-proBNP), midregion pro-atrial natriuretic peptide (MR-proANP) and midregion pro-adrenomedullin (MR-proADM) for discriminating heart failure (HF)-associated effusions. METHODS: NT-proBNP, MR-proANP and MR-proADM were measured by commercially available methodologies in the pleural fluid of a retrospective cohort of 185 consecutive patients with pleural effusions, of whom 95 had acute decompensated HF. Receiver-operating characteristic and area under the curve (AUC) analyses allowed comparisons of the discriminative properties of these biomarkers to be made at their optimal cut-off points. RESULTS: The diagnostic accuracy of NT-proBNP and MR-proANP for HF as quantified by the AUC was 0.935 and 0.918, respectively, whereas MR-proADM was of limited value (AUC = 0.62). A pleural fluid MR-proANP >260 pmol/L or NT-proBNP >1700 pg/mL argues for HF (likelihood ratio (LR) positive >5), while levels below these cut-off values significantly decrease the probability of having the disease (respective LR negative 0.19 and 0.10). The optimal cut-off points for natriuretic peptides were influenced by age, renal function and body mass index. Finally, both NT-proBNP and the albumin gradient correctly identified more than 80% of those cardiac effusions misclassified as exudates by standard criteria. CONCLUSIONS: MR-proANP is as valuable a diagnostic tool as NT-proBNP for diagnosing or excluding HF as the cause of pleural effusion.

Monoclonal antibodies anti-TGFß1 and anti-VEGF inhibit the experimental pleurodesis induced by silver nitrate.

BACKGROUND: The mechanisms underlying pleural inflammation and pleurodesis are poorly understood. We hypothesized that the cytokines transforming growth factor ß (TGFß1) and vascular endothelial growth factor (VEGF) play a major role in pleurodesis after intrapleural silver nitrate (SN) injection. METHOD: Forty rabbits received intrapleurally 0.5% SN alone or 0.5% SN + anti-TGFß1, anti-IL-8, or anti-VEGF. After 28 days, the animals were euthanized and macroscopic pleural adhesions, microscopic pleural fibrosis, and collagen deposition were analyzed for characterization of the degree of pleurodesis (scores 0-4). RESULTS: Scores of pleural adhesions, pleural fibrosis, total collagen, and thin collagen fibers deposition after 28 days were significantly lower for 0.5% SN + anti-TGFß1 and 0.5% SN + anti-VEGF. Significant correlations were found between macroscopic adhesion and microscopic pleural fibrosis with total collagen and thin collagen fibers. CONCLUSIONS: We conclude that both TGFß1 and VEGF, but not IL-8, mediate the pleural inflammatory response and pleurodesis induced by SN.

Solving the Light's criteria misclassification rate of cardiac and hepatic transudates.

BACKGROUND AND OBJECTIVE: Pleural transudates are most commonly due to heart failure (HF) or hepatic hydrothorax (HH), but a number of these effusions are misclassified as exudates by standard (Light's) criteria. The aim of this study was to determine the prevalence of mislabelled transudates and to establish simple alternative parameters to correctly identify them. METHODS: We retrospectively analysed the pleural fluid and serum protein, lactate dehydrogenase and albumin concentrations from 364 cardiac effusions and 102 HH. The serum-to-pleural fluid protein and albumin gradients (serum concentration minus pleural fluid concentration), as well as the pleural fluid-to-serum albumin ratio (pleural fluid concentration divided by the serum concentration) were calculated for the mislabelled transudates. RESULTS: Light's criteria had misclassified more HF-associated effusions than HH (29% vs 18%, P = 0.002). A serum-to-pleural fluid protein gradient >3.1 g/dL correctly identified 55% and 61% of the HF and HH false exudates, respectively. The figures for an albumin gradient >1.2 g/dL were 83% and 62%. Finally, a pleural fluid-to-serum albumin ratio <0.6 had identical accuracy for labelling miscategorized cardiac and liver-related effusions (78% and 77%, respectively). CONCLUSIONS: If the clinical picture is consistent with HF but the pleural fluid meets Light's exudative criteria, the measurement of the albumin rather than the protein gradient is recommended. In the context of cirrhosis, a potentially 'false' exudate is identified better by the pleural fluid-to-serum albumin ratio.

Pleural effusions occurring with right heart failure.

PURPOSE OF REVIEW: Pleural effusions commonly occur in patients with left heart failure. However, there is increasing evidence that patients with pulmonary hypertension and isolated right heart failure frequently have pleural effusions. RECENT FINDINGS: Three recent studies have evaluated the incidence of pleural effusions without an alternate explanation in patients with idiopathic/familial pulmonary arterial hypertension (14%), pulmonary arterial hypertension associated with connective tissue diseases (33%), and portopulmonary hypertension (30%). The majority of patients in all three studies with pleural effusions without an alternate explanation were found to have isolated right heart failure. In these studies, mean right atrial pressures and death during follow-up were significantly higher in patients with pleural effusions and isolated right heart failure compared to patients with no pleural effusions. SUMMARY: Pleural effusions without an alternate explanation occur commonly in at least three subtypes of pulmonary arterial hypertension. The majority of patients with pleural effusions also have isolated right heart failure that is thought to be responsible for the development of the effusions. Patients presenting with pulmonary hypertension should be evaluated for pleural effusions, and if present, should receive a work-up for right heart failure.

Pleural controversy: optimal chest tube size for drainage.

In recent years, a higher and higher percentage of patients with pleural effusions or pneumothorax are being treated with small-bore (10-14 F) chest tubes rather than large-bore (>20 F). However, there are very few randomized controlled studies comparing the efficacy and complication rates with the small- and large-bore catheters. Moreover, the randomized trials that are available have flaws in their design. The advantages of the small-bore catheters are that they are easier to insert and there is less pain with their insertion while they are in place. The placement of the small-bore catheters is probably more optimal when placement is done with ultrasound guidance. Small-bore chest tubes are recommended when pleurodesis is performed. The success of the small-bore indwelling tunnelled catheters that are left in place for weeks documents that the small-bore tubes do not commonly become obstructed with fibrin. Patients with complicated parapneumonic effusions are probably best managed with small-bore catheters even when the pleural fluid is purulent. Patients with haemothorax are best managed with large-bore catheters because of blood clots and the high volume of pleural fluid. Most patients with pneumothorax can be managed with aspiration or small-bore chest tubes. If these fail, a large-bore chest tube may be necessary. Patients on mechanical ventilation with barotrauma induced pneumothoraces are best managed with large-bore chest tubes.

The efficacy of chest radiographs in detecting parapneumonic effusions.

BACKGROUND AND OBJECTIVE: Current guidelines recommend parapneumonic effusions (PPEs) with a thickness of ≥ 10 mm be sampled via thoracentesis. We hypothesized that anteroposterior (AP) CXRs are not as sensitive as posteroanterior (PA) and lateral radiographs in identifying PPEs and should not be routinely used in patients with suspected pneumonia. METHODS: Sixty-one hospitalized patients with pneumonia and PPE were retrospectively studied, all of whom had a CXR and CT scan within 24 h of each other. The CXRs of these patients were independently read by three pulmonologists for an effusion in each hemithorax, which was correlated with measured pleural fluid thickness on chest CT. RESULTS: Lateral, PA and AP radiographs were equivalent in identifying the presence of PPEs. All three views missed more than 10% of PPEs. The sensitivities of lateral, PA and AP CXRs were 85.7%, 82.1% and 78.4%, respectively (P = 0.749); the specificity was 87.5%, 81.3% and 76.4%, respectively (P = 0.198). The majority of effusions missed in each view were on films with lower lobe consolidation. CONCLUSIONS: All three CXR views missed effusions of a size significant enough to warrant thoracentesis. Consideration should be given to obtaining additional imaging at the time patients present with pneumonia, particularly in those with lower lobe consolidation.

Microscopic anatomy of the pleura.

This article describes the anatomy of the pleura, which is made up of five layers. Blood supply and lymphatics are described, as are pleural fluid, mesothelial cells, and Kampmeier foci.

Pleural Fluid Analysis: Are Light's Criteria Still Relevant After Half a Century?

Fifty years from their initial description, Light's criteria are still unhesitatingly accepted as the default reference test for separating pleural transudates and exudates. Efforts should be focused not so much on trying to find an even more reliable technique for categorizing PEs but on improving the misclassification rate of transudates that characterize Light's criteria. Despite their shortcomings, Light's criteria may well continue their reign for another 50 years. Long live the Light's criteria!

The Legend of the Buffalo Chest.

BACKGROUND: The "buffalo chest" is a condition in which a simultaneous bilateral pneumothorax occurs due to a communication of both pleural cavities caused by an iatrogenic or idiopathic fenestration of the mediastinum. This rare condition is known by many clinicians because of a particular anecdote which stated that Native Americans could kill a North American bison with a single arrow in the chest by creating a simultaneous bilateral pneumothorax, due to the animal's peculiar anatomy in which there is one contiguous pleural space due to an incomplete mediastinum. RESEARCH QUESTION: What evidence is there for the existence of buffalo chest? STUDY DESIGN AND METHODS: The term "buffalo chest" and its anecdote were first mentioned in a ''personal communication'' by a veterinarian in the Annals of Surgery in 1984. A mixed method research was performed on buffalo chest and its etiology. A total of 47 cases of buffalo chest were identified in humans. RESULTS: This study found that all authors were referring to the article from 1984 or to each other. Evidence was found for interpleural communications in other mammal species, but no literature on the anatomy of the mediastinum of the bison was found. The main reason for this research was fact-checking the origin of the anecdote and search for evidence for the existence of buffalo chest. Autopsies were performed on eight bison, and four indeed were found to have had interpleural communications. INTERPRETATION: We hypothesize that humans can also have interpleural fenestrations, which can be diagnosed when a pneumothorax occurs.

Pleural effusions due to dasatinib.

PURPOSE OF REVIEW: Dasatinib is a novel tyrosine-kinase inhibitor approved for treatment of BCR-ABL positive chronic myeloid leukemia (CML) and Philadelphia chromosome positive acute lymphoblastic leukemia (ALL) after imatinib failure. Use of dasatinib is frequently complicated by pleural effusions. This review highlights the risk factors for development of effusions as well as characteristics of the pleural fluid. Potential mechanisms involved and a set of management recommendations based on available evidence are also discussed. RECENT FINDINGS: The incidence of dasatinib-associated pleural effusions is approximately 20%. A twice-daily dosing regimen was found to significantly correlate with development of effusions, and therefore once-daily dosing is now approved for treatment of chronic myeloid leukemia and acute lymphoblastic leukemia. Dasatinib-associated pleural effusions are generally lymphocyte-predominant exudates. The mechanism of occurrence is unknown but may involve an immune-mediated pathway or off-target inhibition of platelet-derived growth factor receptor, beta polypeptide. Management typically involves dose interruption or reduction, diuretics and short-term corticosteroid therapy. SUMMARY: Dasatinib is a promising agent for the treatment of refractory chronic myeloid leukemia and acute lymphoblastic leukemia. Its use can be complicated by development of exudative pleural effusions of unclear etiology. Incidence is decreasing with once-daily dosing, but when effusions do occur, most can be managed with specific measures without necessitating discontinuation of therapy.

Pleural effusion in pulmonary embolism.

An estimated 300,000 to 500,000 patients develop a pleural effusion secondary to pulmonary embolism each year in the United States. The pleural effusions due to pulmonary embolism are usually small. They occupy less than one third of the hemithorax in 90% and are frequently manifest only as blunting of the costophrenic angle. The pleural fluid with pulmonary embolism is almost always an exudate. When pulmonary embolism is considered a diagnostic possibility, the clinical probability of pulmonary embolism should be assessed. If the probability is low, measurement of D-dimers is useful. If the D-dimer test is negative, the diagnosis is virtually excluded. If the D-dimer test is positive or if there is a high clinical probability of pulmonary embolism, the best test to assess the possibility of pulmonary embolism is probably the computed tomographic angiogram (CTA). Patients who have a high probability of pulmonary embolism should be anticoagulated while the definitive test is being performed. The presence of a pleural effusion does not alter the standard treatment for pulmonary embolism. The two complications of pleural effusions in patients with pulmonary embolism are hemothorax and pleural infection. If the pleural effusion increases in size while a patient is being treated for pulmonary embolism, a diagnostic thoracentesis should be performed to rule out these complications.

Update on tuberculous pleural effusion.

The possibility of tuberculous pleuritis should be considered in every patient with an undiagnosed pleural effusion, for if this diagnosis is not made the patient will recover only to have a high likelihood of subsequently developing pulmonary or extrapulmonary tuberculosis Between 3% and 25% of patients with tuberculosis will have tuberculous pleuritis. The incidence of pleural tuberculosis is higher in patients who are HIV positive. Tuberculous pleuritis usually presents as an acute illness with fever, cough and pleuritic chest pain. The pleural fluid is an exudate that usually has predominantly lymphocytes. Pleural fluid cultures are positive for Mycobacterium tuberculosis in less than 40% and smears are virtually always negative. The easiest way to establish the diagnosis of tuberculous pleuritis in a patient with a lymphocytic pleural effusion is to generally demonstrate a pleural fluid adenosine deaminase level above 40 U/L. Lymphocytic exudates not due to tuberculosis almost always have adenosine deaminase levels below 40 U/L. Elevated pleural fluid levels of gamma-interferon also are virtually diagnostic of tuberculous pleuritis in patients with lymphocytic exudates. In questionable cases the diagnosis can be established by demonstrating granulomas or organisms on tissue specimens obtained via needle biopsy of the pleura or thoracoscopy. The chemotherapy for tuberculous pleuritis is the same as that for pulmonary tuberculosis.

Iodopovidone is as effective as doxycycline in producing pleurodesis in rabbits.

BACKGROUND AND OBJECTIVE: The mechanism by which iodopovidone achieves pleurodesis is unknown. This study investigated whether iodopovidone is as effective as doxycycline in producing pleurodesis and whether systemic corticosteroids diminish its efficacy. METHODS: Four groups of seven New Zealand rabbits were assigned to the following intrapleural treatment groups: 2 mL of 2% iodopovidone, 2 mL of 4% iodopovidone, 2 mL of 4% iodopovidone plus 0.8 mg/kg triamcinolone intramuscularly weekly and 10 mL/kg doxycycline in 2 mL. Pleural fluid was collected 24, 48 and 72 h after intrapleural injections and analysed for WCC, protein and LDH levels. The rabbits were killed 2 weeks after the injections. Pleurodesis was graded macroscopically on a scale from 1 to 8. The degree of microscopic pleural fibrosis and pleural inflammation was graded from the HE stain slides. RESULTS: The mean volume of pleural fluid as well as the mean total WCC was significantly lower in the steroid-treated group than in the other groups. The degree of the resulting pleurodesis was similar in the 2% iodopovidone (7.00 +/- 1.29), 4% iodopovidone (7.71 +/- 0.76) and doxycycline (7.14 +/- 0.90) groups (P > 0.05) whereas the pleurodesis score of the steroid group (3.71 +/- 1.98) was significantly lower than all other groups (P < 0.05). The degree of microscopic pleural fibrosis and pleural inflammation was significantly lower in the steroid group than in the 2% iodopovidone or 4% iodopovidone group. CONCLUSIONS: Both 2% and 4% iodopovidone can induce pleurodesis as efficaciously as doxycycline in rabbits. Systemic corticosteroids significantly decrease the efficacy of iodopovidone in producing pleurodesis.

Usefulness of triglyceride levels in pleural fluid.

The determination of pleural fluid triglycerides (PF-TRIG) is useful in the diagnosis of chylothorax, but its diagnostic value for other causes of pleural effusions is unknown. The aim of this study was to evaluate the usefulness of PF-TRIG in the diagnosis of other pleural effusions and investigate the origin of their increase in these fluids. We studied 390 pleural effusions (75 tuberculous, 107 neoplastic, 39 parapneumonic, 30 miscellaneous, 42 idiopathic, and 97 transudates). The correlation was analyzed with the PF-TRIG values as the dependent variable and serum triglycerides (S-TRIG) and the pleural fluid/serum protein ratio (PF/S PROT ratio) as independent variables. The PF-TRIG was significantly higher in exudates. The sensitivity of PF-TRIG for identifying exudates was 84.3%, specificity 61.9%. The correlation between PF-TRIG and S-TRIG was significant in the exudates and in the total pleural effusions. There was a significant correlation between PF-TRIG and S-TRIG and capillary permeability, which worsened when looking at the transudates and exudates separately. No correlations were found between the PF-TRIG and the number of red cells and white cells in any of the groups. Except for diagnosing a chylothorax, the determination of triglycerides in pleural fluid does not appear to be justified. The cause of the increase in PF-TRIG in exudates could not be established because the correlations obtained were insufficient to be able to predict PF-TRIG values from their serum values and the measurement of capillary permeability.

The Impact of Gravity vs Suction-driven Therapeutic Thoracentesis on Pressure-related Complications: The GRAVITAS Multicenter Randomized Controlled Trial.

BACKGROUND: Thoracentesis can be accomplished by active aspiration or drainage with gravity. This trial investigated whether gravity drainage could protect against negative pressure-related complications such as chest discomfort, re-expansion pulmonary edema, or pneumothorax compared with active aspiration. METHODS: This prospective, multicenter, single-blind, randomized controlled trial allocated patients with large free-flowing effusions estimated ≥ 500 mL 1:1 to undergo active aspiration or gravity drainage. Patients rated chest discomfort on 100-mm visual analog scales prior to, during, and following drainage. Thoracentesis was halted at complete evacuation or for persistent chest discomfort, intractable cough, or other complication. The primary outcome was overall procedural chest discomfort scored 5 min following the procedure. Secondary outcomes included measures of discomfort and breathlessness through 48 h postprocedure. RESULTS: A total of 142 patients were randomized to undergo treatment, with 140 in the final analysis. Groups did not differ for the primary outcome (mean visual analog scale score difference, 5.3 mm; 95% CI, -2.4 to 13.0; P = .17). Secondary outcomes of discomfort and dyspnea did not differ between groups. Comparable volumes were drained in both groups, but the procedure duration was significantly longer in the gravity arm (mean difference, 7.4 min; 95% CI, 10.2 to 4.6; P < .001). There were no serious complications. CONCLUSIONS: Thoracentesis via active aspiration and gravity drainage are both safe and result in comparable levels of procedural comfort and dyspnea improvement. Active aspiration requires less total procedural time. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT03591952; URL: www.clinicaltrials.gov.