Development and Assessment of Simulation-Based Point-of-Care Ultrasound Curriculum in Undergraduate Medical Education.

OBJECTIVES: Implementation barriers and lack of standardized point-of-care ultrasound (POCUS) curricula make the development of effective POCUS curricula and methods of assessment challenging. The authors aim to develop a longitudinal POCUS curriculum through staged intervention. In the first stage, the authors hypothesized that the use of high-fidelity ultrasound simulation during the Internal Medicine clerkship would improve POCUS confidence and knowledge among medical students, minimizing the need for trained faculty. METHODS: A quasi-experimental study of third-year students on the Internal Medicine clerkship at a large academic medical center in the United States was performed assessing the efficacy of ultrasound simulation use. The control group consisted of students who received baseline POCUS education during teaching rounds but did not have access to the ultrasound simulator. The experimental group consisted of students who, in addition to baseline POCUS education, had access to a high-fidelity ultrasound simulator throughout the clerkship for a minimum of 1 hour per week. Students in both the control and experimental groups completed a pre- and post-intervention confidence survey and knowledge-based examination. RESULTS: Eighty-two percent (50/61) of students completed pre- and post-tests, with the control group demonstrating no significant difference in POCUS confidence or knowledge. After exposure to the ultrasound simulator, the experimental group demonstrated statistically significant improvement in POCUS confidence and overall POCUS knowledge (p < .01). CONCLUSION: The use of high-fidelity ultrasound simulation can improve POCUS confidence and knowledge among medical students while addressing common barriers to the implementation of a POCUS curriculum. Despite showing statistically significant improvement in overall knowledge, the results did not appear to hold educational significance. Additional POCUS educational methods are necessary to overcome cognitive bias and potential overconfidence. The next stage of curriculum development will include resident-led POCUS workshops to supplement simulation.

Congenital Mpox Syndrome (Clade I) in Stillborn Fetus after Placental Infection and Intrauterine Transmission, Democratic Republic of the Congo, 2008.

We report the autopsy pathology findings of a 21-week stillborn fetus with congenital mpox syndrome that occurred in the Democratic Republic of the Congo in 2008. The fetus acquired mpox from the mother after intrauterine transplacental monkeypox virus transmission. We confirmed monkeypox virus infection in the mother, fetus, and placenta by using a monkeypox virus-specific quantitative PCR. Subtyping of the virus was not performed, but the mother and fetus were almost certainly infected with the clade I variant that was endemic in the Democratic Republic of the Congo at the time. Risk for intrauterine infection appears to differ between virus clades, but clinicians should be aware of potential for intrauterine monkeypox virus transmission among pregnant persons during ongoing and future mpox outbreaks.

Development of a specific MPXV antigen detection immunodiagnostic assay.

Human monkeypox (mpox) has recently become a global public health emergency; however, assays that detect mpox infection are not widely available, largely due to cross-reactivity within the Orthopoxvirus genus. Immunoassay development was largely confined to researchers who focus on biothreats and endemic areas (Central and West Africa) until the 2022 outbreak. As was noted in the COVID-19 pandemic, antigen detection assays, integrated with molecular assays, are necessary to help curb the spread of disease. Antigen-detecting immunoassays offer the advantage of providing results ranging from within min to h and in lateral flow formats; they can be deployed for point-of-care, home, or field use. This study reports the development of an mpox-specific antigen detection immunoassay developed on a multiplexed, magnetic-bead-based platform utilizing reagents from all research sectors (commercial, academic, and governmental). Two semi-quantitative assays were developed in parallel and standardized with infectious mpox virus (MPXV) cell culture fluid and MPXV-positive non-human primate (NHP) sera samples. These assays could detect viral antigens in serum, were highly specific toward MPXV as compared to other infectious orthopoxviruses (vaccinia virus, cowpox virus, and camelpox virus), and exhibited a correlation with quantitative PCR results from an NHP study. Access to a toolbox of assays for mpox detection will be key for identifying cases and ensuring proper treatment, as MPXV is currently a global traveler.

Ultrasound-guided pleural biopsy following a non-diagnostic thoracentesis for non-small cell lung cancer.

We report a case of a 65-year-old man with a cavitary lung mass and parietal-based pleural nodules in which a pleural ultrasound-guided approach yielded a definitive diagnosis of stage IV non-small cell lung carcinoma. Computed tomography-guided biopsy is often preferred approach for the majority of United States hospitals for sampling pleural nodules as compared to US. The advantages of an US-guided approach include [1]: increased portability [2]; decreased procedure time [3]; reduced reliance on dedicated ancillary support staff [4]; need for local anesthesia only [5]; lack of ionizing radiation exposure; and [6] cost reduction.

Pressure-Dependent Pneumothorax and Air Leak: Physiology and Clinical Implications.

Pressure-dependent pneumothorax is a common clinical event, often occurring after pleural drainage in patients with visceral pleural restriction, partial lung resection, or lobar atelectasis from bronchoscopic lung volume reduction or an endobronchial obstruction. This type of pneumothorax and air leak is clinically inconsequential. Failure to appreciate the benign nature of such air leaks may result in unnecessary pleural procedures or prolonged hospital stay. This review suggests that identification of pressure-dependent pneumothorax is clinically important because the air leak that results is not related to a lung injury that requires repair but rather to a physiological consequence of a pressure gradient. A pressure-dependent pneumothorax occurs during pleural drainage in patients with lung-thoracic cavity shape/size mismatch. It is caused by an air leak related to a pressure gradient between the subpleural lung parenchyma and the pleural space. Pressure-dependent pneumothorax and air leak do not need any further pleural interventions.

Clinical characterization and placental pathology of mpox infection in hospitalized patients in the Democratic Republic of the Congo.

We describe the results of a prospective observational study of the clinical natural history of human monkeypox (mpox) virus (MPXV) infections at the remote L'Hopital General de Reference de Kole (Kole hospital), the rainforest of the Congo River basin of the Democratic Republic of the Congo (DRC) from March 2007 until August 2011. The research was conducted jointly by the Institute National de Recherche Biomedical (INRB) and the US Army Medical Research Institute of Infectious Diseases (USAMRIID). The Kole hospital was one of the two previous WHO Mpox study sites (1981-1986). The hospital is staffed by a Spanish Order of Catholic Nuns from La Congregation Des Soeurs Missionnaires Du Christ Jesus including two Spanish physicians, who were members of the Order as well, were part of the WHO study on human mpox. Of 244 patients admitted with a clinical diagnosis of MPXV infection, 216 were positive in both the Pan-Orthopox and MPXV specific PCR. The cardinal observations of these 216 patients are summarized in this report. There were three deaths (3/216) among these hospitalized patients; fetal death occurred in 3 of 4 patients who were pregnant at admission, with the placenta of one fetus demonstrating prominent MPXV infection of the chorionic villi. The most common complaints were rash (96.8%), malaise (85.2%), sore throat (78.2%), and lymphadenopathy/adenopathy (57.4%). The most common physical exam findings were mpox rash (99.5%) and lymphadenopathy (98.6%). The single patient without the classic mpox rash had been previously vaccinated against smallpox. Age group of less than 5 years had the highest lesion count. Primary household cases tended to have higher lesion counts than secondary or later same household cases. Of the 216 patients, 200 were tested for IgM & IgG antibodies (Abs) to Orthopoxviruses. All 200 patients had anti-orthopoxvirus IgG Abs; whereas 189/200 were positive for IgM. Patients with hypoalbuminemia had a high risk of severe disease. Patients with fatal disease had higher maximum geometric mean values than survivors for the following variables, respectively: viral DNA in blood (DNAemia); maximum lesion count; day of admission mean AST and ALT.

Atraumatic Acute Paraspinal Compartment Syndrome in a Patient With McArdle's Disease.

A 60-year-old male presented to the emergency room with complaints of back pain overlying the left lumbar area and ipsilateral thigh numbness. The left erector spinae musculature was rigid, tense, and painful to palpation. An elevated serum creatine kinase was identified, and a computed tomography scan showed evidence of left paraspinal musculature congestion. Past medical/surgical history was significant for McArdle's disease and bilateral forearm fasciotomies. The patient underwent lumbosacral fasciotomy with no obvious myonecrosis. The patient was discharged home after skin closure and has since been seen in clinic with no residual pain or change in baseline functional status. This case may represent the first reported atraumatic exertional lumbar compartment syndrome in a patient with McArdle's disease. Prompt operative intervention was effective in this case of acute atraumatic paraspinal compartment syndrome and resulted in an excellent functional outcome.

Design and Optimization of a Monkeypox virus Specific Serological Assay.

Monkeypox virus (MPXV), a member of the Orthopoxvirus (OPXV) genus, is a zoonotic virus, endemic to central and western Africa that can cause smallpox-like symptoms in humans with fatal outcomes in up to 15% of patients. The incidence of MPXV infections in the Democratic Republic of the Congo, where the majority of cases have occurred historically, has been estimated to have increased as much as 20-fold since the end of smallpox vaccination in 1980. Considering the risk global travel carries for future disease outbreaks, accurate epidemiological surveillance of MPXV is warranted as demonstrated by the recent Mpox outbreak, where the majority of cases were occurring in non-endemic areas. Serological differentiation between childhood vaccination and recent infection with MPXV or other OPXVs is difficult due to the high level of conservation within OPXV proteins. Here, a peptide-based serological assay was developed to specifically detect exposure to MPXV. A comparative analysis of immunogenic proteins across human OPXVs identified a large subset of proteins that could potentially be specifically recognized in response to a MPXV infection. Peptides were chosen based upon MPXV sequence specificity and predicted immunogenicity. Peptides individually and combined were screened in an ELISA against serum from well-characterized Mpox outbreaks, vaccinee sera, and smallpox sera collected prior to eradication. One peptide combination was successful with ~86% sensitivity and ~90% specificity. The performance of the assay was assessed against the OPXV IgG ELISA in the context of a serosurvey by retrospectively screening a set of serum specimens from the region in Ghana believed to have harbored the MPXV-infected rodents involved in the 2003 United States outbreak.

Effect of Androgen Suppression on Clinical Outcomes in Hospitalized Men With COVID-19: The HITCH Randomized Clinical Trial.

Importance: SARS-CoV-2 entry requires the TMPRSS2 cell surface protease. Antiandrogen therapies reduce expression of TMPRSS2. Objective: To determine if temporary androgen suppression induced by degarelix improves clinical outcomes of inpatients hospitalized with COVID-19. Design, Setting, and Participants: The Hormonal Intervention for the Treatment in Veterans With COVID-19 Requiring Hospitalization (HITCH) phase 2, placebo-controlled, double-blind, randomized clinical trial compared efficacy of degarelix plus standard care vs placebo plus standard care on clinical outcomes in men hospitalized with COVID-19 but not requiring invasive mechanical ventilation. Inpatients were enrolled at 14 Department of Veterans Affairs hospitals from July 22, 2020, to April 8, 2021. Data were analyzed from August 9 to October 15, 2021. Interventions: Patients stratified by age, history of hypertension, and disease severity were centrally randomized 2:1 to degarelix, (1-time subcutaneous dose of 240 mg) or a saline placebo. Standard care included but was not limited to supplemental oxygen, antibiotics, vasopressor support, peritoneal dialysis or hemodialysis, intravenous fluids, remdesivir, convalescent plasma, and dexamethasone. Main Outcomes and Measures: The composite primary end point was mortality, ongoing need for hospitalization, or requirement for mechanical ventilation at day 15 after randomization. Secondary end points were time to clinical improvement, inpatient mortality, length of hospitalization, duration of mechanical ventilation, time to achieve a temperature within reference range, maximum severity of COVID-19, and the composite end point at 30 days. Results: The trial was stopped for futility after the planned interim analysis, at which time there were 96 evaluable patients, including 62 patients randomized to the degarelix group and 34 patients in the placebo group, out of 198 initially planned. The median (range) age was 70.5 (48-85) years. Common comorbidities included chronic obstructive pulmonary disorder (15 patients [15.6%]), hypertension (75 patients [78.1%]), cardiovascular disease (27 patients [28.1%]), asthma (12 patients [12.5%]), diabetes (49 patients [51.0%]), and chronic respiratory failure requiring supplemental oxygen at baseline prior to COVID-19 (9 patients [9.4%]). For the primary end point, there was no significant difference between the degarelix and placebo groups (19 patients [30.6%] vs 9 patients [26.5%]; P = .67). Similarly, no differences were observed between degarelix and placebo groups in any secondary end points, including inpatient mortality (11 patients [17.7%] vs 6 patients [17.6%]) or all-cause mortality (11 patients [17.7%] vs 7 patents [20.6%]). There were no differences between degarelix and placebo groups in the overall rates of adverse events (13 patients [21.0%] vs 8 patients [23.5%) and serious adverse events (19 patients [30.6%] vs 13 patients [32.4%]), nor unexpected safety concerns. Conclusions and Relevance: In this randomized clinical trial of androgen suppression vs placebo and usual care for men hospitalized with COVID-19, degarelix did not result in amelioration of COVID-19 severity. Trial Registration: ClinicalTrials.gov Identifier: NCT04397718.

Association between Drainage-Dependent Prolonged Air Leak after Partial Lung Resection and Clinical Outcomes: A Prospective Cohort Study.

Rationale: Prolonged air leak (PAL) after partial lung resection can occur owing to surgical complications or in the presence of residual thoracic space. The former type results in drainage-independent PAL (DIPAL), whereas the latter type results in drainage-dependent PAL (DDPAL). DDPAL is described after thoracentesis in patients with nonexpandable lung, where the thoracostomy tube can be discontinued safely despite an ongoing air leak. This distinction is clinically relevant, as in the presence of DDPAL, tube thoracostomy can be safely discontinued without the need for further interventions. Objectives: To determine the frequency and clinical relevance of DDAPL and DIPAL in patients with PAL after partial lung resection. Methods: We prospectively identified consecutive patients with PAL after partial lung resection. Pleural manometry was performed 3-5 days after surgery. Pleural pressure was measured for 20 minutes after clamping the thoracostomy tube. DDPAL was diagnosed if the end-expiratory pleural pressure remained stable after plateauing in the absence of respiratory symptoms. Results: Of 225 patients who underwent lung resection, we identified 22 (10%) who had PAL. Twenty patients had adequate pleural manometry readings. The majority, 16/20 (80%), had DDPAL and had lower median hospital length of stay than those with DIPAL (6.9 vs. 11 days; P = 0.02). All patients with DIPAL required reexploration surgery, whereas only one patient with DDPAL underwent reexploration surgery. Conclusions: Most PALs after partial lung resection are DDPAL. Patients with DDPAL have lower hospital length of stay and less need for reexploration surgery than those with DIPAL.

Pneumothorax in critically ill patients with COVID-19 infection: Incidence, clinical characteristics and outcomes in a case control multicenter study.

BACKGROUND: The clinical features and outcomes of mechanically ventilated patients with COVID-19 infection who develop a pneumothorax has not been rigorously described or compared to those who do not develop a pneumothorax. PURPOSE: To determine the incidence, clinical characteristics, and outcomes of critically ill patients with COVID-19 infection who developed pneumothorax. In addition, we compared the clinical characteristics and outcomes of mechanically ventilated patients who developed a pneumothorax with those who did not develop a pneumothorax. METHODS: This study was a multicenter retrospective analysis of all adult critically ill patients with COVID-19 infection who were admitted to intensive care units in 4 tertiary care centers in the United States. RESULTS: A total of 842 critically ill patients with COVID-19 infection were analyzed, out of which 594 (71%) were mechanically ventilated. The overall incidence of pneumothorax was 85/842 (10%), and 80/594 (13%) in those who were mechanically ventilated. As compared to mechanically ventilated patients in the non-pneumothorax group, mechanically ventilated patients in the pneumothorax group had worse respiratory parameters at the time of intubation (mean PaO2:FiO2 ratio 105 vs 150, P<0.001 and static respiratory system compliance: 30ml/cmH2O vs 39ml/cmH2O, P = 0.01) and significantly higher in-hospital mortality (63% vs 49%, P = 0.04). CONCLUSION: The overall incidence of pneumothorax in mechanically ventilated patients with COVID-19 infection was 13%. Mechanically ventilated patients with COVID-19 infection who developed pneumothorax had worse gas exchange and respiratory mechanics at the time of intubation and had a higher mortality compared to those who did not develop pneumothorax.

The Relationship of Pleural and Pericardial Effusion With Pulmonary Hemodynamics in Patients With Pulmonary Hypertension.

BACKGROUND: The relationship between the presence of pleural and pericardial effusion in reference to hemodynamic parameters remains unclear in ambulatory patients with pulmonary hypertension (PH). METHODS: Consecutive patients who underwent right catheterization (RHC) for the evaluation of pulmonary hypertension were enrolled. Point-of- care ultrasound was performed prior to the RHC to determine the presence of pleural effusion and pericardial effusion. We conducted a cross-sectional study to determine the association between presence of pericardial and pleural effusion with pulmonary hemodynamic variables. RESULTS: Twenty-five (78.1%) of 32 patients had evidence of PH by RHC. Mean pulmonary artery pressure of the population was 40.6 mmHg, and 68% (17/25) had WHO group I PH. Six (24.0%) of 25 PH patients had pleural effusions identified, of which 4 out of 6 (66.7%) had a pulmonary artery wedge pressure >15 mmHg. Eleven (44.0%) of the 25 PH patients were also found to have pericardial effusions, and most of those patients 10/11(90.9%) had an elevated right atrial pressure >10 mmHg. The presence of a pleural effusion was associated with a pulmonary artery wedge pressure >15 mmHg (p = 0.032) and the presence of a pericardial effusion was associated with a right atrial pressure >10 mmHg (p = 0.004). Detection of pleural effusion had a poor positive predictive value (67%) for the presence of pulmonary venous hypertension, whereas presence of a pericardial effusion was highly predictive (89%) of the presence of systemic venous hypertension. CONCLUSIONS: Systemic venous hypertension was associated with the presence of pericardial effusions, while pulmonary venous hypertension is associated with pleural effusion development in ambulatory patients with pulmonary hypertension.

Pleural manometry: techniques, applications, and pitfalls.

Pleural manometry (PM) is a novel tool that allows direct measurement of the pressure in the pleural space in the presence of either a pleural effusion or a pneumothorax. Originally it was used to guide therapy for tuberculosis (TB) before the development of anti-TB medications. It was relegated to highly specialized centers for thoracoscopies until Light used it to investigate pleural effusions in the 1980s. However, there remains lack of robust data to support the routine use of PM. Recently additional published studies have generated renewed interest supporting the use of PM in specialized cases of complex pleural disorders. In this paper we summarize the current different techniques, applications, and pitfalls for the use of PM.

Diagnostic Accuracy of Thoracic Ultrasonography to Differentiate Transudative From Exudative Pleural Effusion.

BACKGROUND: There are limited data examining the diagnostic accuracy of thoracic ultrasonography (TUS) in distinguishing transudative from exudative pleural effusions. RESEARCH QUESTION: What is the diagnostic accuracy of TUS in distinguishing transudative from exudative effusions in consecutive patients with pleural effusion? STUDY DESIGN AND METHODS: Consecutive patients who underwent TUS and subsequently a diagnostic thoracentesis with a pleural fluid analysis were identified. TUS images of the pleural effusions were interpreted by previously published criteria. We evaluated the diagnostic performance of TUS findings in predicting a transudative vs exudative pleural effusions and specific pleural diagnoses. RESULTS: We evaluated 300 consecutive pleural effusions in 285 patients. The pleural effusions were classified as exudative in 229 of 300 cases (76%). TUS showed anechoic effusions in 122 of 300 cases (40%) and complex effusions in 178 of 300 cases (60%). An anechoic appearance on TUS was associated with exudative effusions (68/122; 56%) as compared with transudative effusions (54/122; 44%). The presence of a complex-appearing effusion on TUS was highly predictive of an exudative effusion (positive predictive value of 90%). However, none of the four TUS characteristics were highly specific of a pleural diagnosis. INTERPRETATION: Thoracic ultrasonography is inadequate to diagnose a transudative pleural effusion reliably. Although the TUS findings of a complex effusion may suggest an exudative pleural effusion, specific pleural diagnoses cannot be predicted confidently.

The Relationship of Pleural Manometry With Postthoracentesis Chest Radiographic Findings in Malignant Pleural Effusion.

BACKGROUND: Both elevated pleural elastance (E-PEL) and radiographic evidence of incomplete lung expansion following thoracentesis have been used to exclude patients with a malignant pleural effusion (MPE) from undergoing pleurodesis. This article reports on a cohort of patients with MPE in whom complete drainage was attempted with pleural manometry to determine the frequency of E-PEL and its relation with postthoracentesis radiographic findings. METHODS: Seventy consecutive patients with MPE who underwent therapeutic pleural drainage with pleural manometry were identified. The pressure/volume curves were constructed and analyzed to determine the frequency of E-PEL and the relation of PEL to the postthoracentesis chest radiographic findings. RESULTS: E-PEL and incomplete lung expansion were identified in 36 of 70 (51.4%) and 38 of 70 (54%) patients, respectively. Patients with normal PEL had an OR of 6.3 of having complete lung expansion compared with those with E-PEL (P = .0006). However, 20 of 70 (29%) patients exhibited discordance between postprocedural chest radiographic findings and the pleural manometry results. Among patients who achieved complete lung expansion on the postdrainage chest radiograph, 9 of 32 (28%) had an E-PEL. In addition, PEL was normal in 11 of 38 (34%) patients who had incomplete lung expansion as detected according to the postthoracentesis chest radiograph. CONCLUSIONS: E-PEL and incomplete lung expansion postthoracentesis are frequently observed in patients with MPE. Nearly one-third of the cohort exhibited discordance between the postprocedural chest radiographic findings and pleural manometry results. These findings suggest that a prospective randomized trial should be performed to compare both modalities (chest radiograph and pleural manometry) in predicting pleurodesis outcome.

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.

Routine monitoring with pleural manometry during therapeutic large-volume thoracentesis to prevent pleural-pressure-related complications: a multicentre, single-blind randomised controlled trial.

BACKGROUND: In patients with non-expandable lung, removal of pleural fluid can result in excessively negative pleural pressure, which is associated with chest discomfort, pneumothorax, and re-expansion pulmonary oedema. Pleural manometry is widely used to safeguard against pressure-related complications during thoracentesis despite little evidence to support the approach. We investigated whether monitoring of pleural pressure with manometry during thoracentesis could protect against complications compared with assessment of symptoms alone. METHODS: We did a prospective randomised single-blind trial involving patients with large pleural effusions at two academic medical centres in, Nashville, TN, and Baltimore, MD, USA. Eligible patients were adults with free-flowing effusions estimated to be at least 0·5 L who could remain seated throughout the procedure. Patients were randomly assigned 1:1 to receive thoracentesis guided by symptoms only (control) or by symptoms plus manometry at timepoints based on volume drained. The randomisation schedule was computer generated, used permuted blocks of four and six, and was stratified by participating institution. Patients, who were masked to study-group assignment, were asked to rate chest discomfort on 100 mm visual analogue scales before, during, and after drainage. In both groups drainage was discontinued before complete evacuation of pleural fluid if patients developed persistent chest discomfort, intractable cough, or other complications. In the manometry group, an additional criterion for stopping was if end-expiratory pleural pressure was lower than -20 cm H2O or declined by more than 10 cm H2O between two measurements to a value less than or equal to -10 cm H2O. The primary outcome was overall chest discomfort from before the start to after the procedure measured by patients 5 min after the end of drainage. Analysis was by modified intention to treat (ie, included all patients with any procedure or outcome data). This trial is registered with ClinicalTrials.gov, number NCT02677883. FINDINGS: Between March 4, 2016, and Sept 8, 2017, 191 patients were screened, of whom 128 were randomly assigned treatment and 124 were included in the final analysis (62 in each group). Four patients were excluded because of manometer malfunction (n=2), inability to access effusion due to pleural tumour burden (n=1), and inability to remain seated (n=1). Groups did not differ for the primary outcome (mean difference in chest discomfort score 2·4 mm, 95% CI -5·7 to 10·5, p=0·56). Six (10%) of 62 patients in the control group had asymptomatic pneumothorax ex vacuo compared with none in the manometry group (p=0·01). No serious complications occurred in either group. INTERPRETATION: Measurement of pleural pressure by manometry during large-volume thoracentesis does not alter procedure-related chest discomfort. Our findings do not support the routine use of this approach. FUNDING: Centurion Medical Products.