Pleural effusions and pneumothorax: Beyond simple plumbing: Expert opinions on knowledge gaps and essential next steps

Prevalence and characteristics of minimal pleural fluid on screening chest MRI

BACKGROUND

Minimal pleural fluid is often seen incidentally on chest MRI. However, its prevalence and clinical characteristics remain unknown.

METHODS

This retrospective observational study included 2726 participants who underwent comprehensive medical check-ups for screening, including chest CT and MRI, and transthoracic echocardiography between March 2018 and February 2019. Pleural fluid on MRI was manually measured for maximum thickness. Its distribution, change over time, and relevance to participant characteristics were analyzed. The pulmonary function data of 82 participants and their associations with fluid were also analyzed.

RESULTS

Of the 2726 participants (mean age ± standard deviation, 59 ± 11 years), 2009 (73.7%) had minimal pleural fluid (thickness, 1-9 mm) on either side, with right-sided fluid being more frequent than left-sided fluid (P < 0.001). Negligible changes in fluid thickness were observed one year later. The following parameters were associated with less fluid: age, ≥65 years (P < 0.001); male sex (P = 0.006); current smoking (P < 0.001); body mass index, ≥25 kg/m2 (P < 0.001); and mean arterial pressure, ≥100 mmHg (P = 0.01), whereas a ratio between early mitral inflow velocity and mitral annular early diastolic velocity>14 was associated with more fluid (P = 0.01). The presence of fluid was an independent explanatory variable for a higher percentage of predicted vital capacity (P = 0.048).

CONCLUSIONS

MRI was highly sensitive in detecting minimal pleural fluid. Pleural fluid found on MRI for health screening was assumed to be physiological and fluid thickness at the steady state might be variable among participants depending on age, sex, smoking habits, body shape, blood pressure, and cardiac diastolic capacity.

The Biological Role of Pleural Fluid PAI-1 and Sonographic Septations in Pleural Infection: Analysis of a Prospectively Collected Clinical Outcome Study

Rationale: Sonographic septations are assumed to be important clinical predictors of outcome in pleural infection, but the evidence for this is sparse. The inflammatory and fibrinolysis-associated intrapleural pathway(s) leading to septation formation have not been studied in a large cohort of pleural fluid (PF) samples with confirmed pleural infection matched with ultrasound and clinical outcome data. Objectives: To assess the presence and severity of septations against baseline PF PAI-1 (Plasminogen-Activator Inhibitor-1) and other inflammatory and fibrinolysis-associated proteins as well as to correlate these with clinically important outcomes. Methods: We analyzed 214 pleural fluid samples from PILOT (Pleural Infection Longitudinal Outcome Study), a prospective observational pleural infection study, for inflammatory and fibrinolysis-associated proteins using the Luminex platform. Multivariate regression analyses were used to assess the association of pleural biological markers with septation presence and severity (on ultrasound) and clinical outcomes. Measurements and Main Results: PF PAI-1 was the only protein independently associated with septation presence (P < 0.001) and septation severity (P = 0.003). PF PAI-1 concentrations were associated with increased length of stay (P = 0.048) and increased 12-month mortality (P = 0.003). Sonographic septations alone had no relation to clinical outcomes. Conclusions: In a large and well-characterized cohort, this is the first study to associate pleural biological parameters with a validated sonographic septation outcome in pleural infection. PF PAI-1 is the first biomarker to demonstrate an independent association with mortality. Although PF PAI-1 plays an integral role in driving septation formation, septations themselves are not associated with clinically important outcomes. These novel findings now require prospective validation.

Implementation of evidence on management of pleural diseases: insights from a territory-wide survey of clinicians in Hong Kong

BACKGROUND

Major advances in management of common pleural diseases have taken place in the past decade. However, pleural diseases are often managed by physicians of diverse training background and research on implementation of new knowledge is scanty. We aim to evaluate the practice pattern in pleural medicine among physicians in Hong Kong, for identification of possible gaps for clinical service improvement.

METHODS

The Hong Kong Thoracic Society undertook a cross-sectional questionnaire survey in 2019, targeting clinicians of various subspecialties in internal medicine and levels of experience (basic and higher trainees, specialists) from twelve regional hospitals of diverse service scopes throughout Hong Kong. Respondents were selected by non-probability quota sampling. The questionnaire tool consisted of 46 questions covering diagnostic and therapeutic aspects of common pleural diseases. The responses were anonymous, and analysed independently using SPSS statistics software.

RESULTS

The survey collected 129 responses, 47(36%) were from clinicians specialized in respiratory medicine. Majority of the respondents (98%) managed pleural diseases, including performing pleural procedures in their practice. Fifty-five percent of all the respondents had not received any formal training in transthoracic ultrasonography. A significant proportion of clinicians were unaware of pleuroscopy for investigation of exudative pleural effusion, indwelling pleural catheter for recurrent malignant pleural effusion, and combined intra-pleural Alteplase plus DNase for treatment of pleural infection (30%, 15% and 70% of non-respiratory clinicians respectively). Significant heterogeneity was found in the management of pleural infection, malignant pleural effusion and pneumothorax among respiratory versus non-respiratory clinicians. Contributing factors to the observed heterogeneity included lack of awareness or training, limited accessibility of drugs, devices, or dedicated service support.

CONCLUSION

Significant heterogeneity in management of pleural diseases was observed among medical clinicians in Hong Kong. Continuous medical education and training provision for both specialists and non-specialists has to be strengthened to enhance the implementation of advances, improve quality and equity of healthcare provision in pleural medicine.

Ambulatory pneumothorax management in a district general hospital

BACKGROUND

The pleural vent (PV) is a new drain and valve device enabling ambulatory pneumothorax management. This study analysed the characteristics and outcomes of patients with pneumothorax treated with a PV.

METHODS

The characteristics and outcomes of 49 patients with pneumothorax treated with a PV between 1 March 2018 and 1 February 2021 were retrospectively analysed.

RESULTS

The mean number of days the PV remained in situ for all patients was 5.6 days, range 0-25, IQR 3-7. Forty patients were managed completely in the ambulatory setting. The total number of days with the PVs in situ was 248. Approximate inpatient bed days saved are 240-320 days. Complications requiring a change in management occurred in nine (18.3%) cases.

CONCLUSION

This single-centre study shows that ambulatory pneumothorax management with the PV is feasible and associated with inpatient bed savings. Complication rates are less than previously described.

Comparison of clinical manifestation among Australian Indigenous and non- Indigenous patients presenting with pleural effusion

BACKGROUND

There is sparse evidence in the literature in relation to the nature and causes of pleural effusion among Australian Indigenous population.

METHODS

In this retrospective study, Indigenous and non-Indigenous adults diagnosed to have pleural effusion over a two-year study period were included for comparative analysis.

RESULTS

Of the 314 patients, 205 (65%) were non-Indigenous and 52% were males. In comparison to non-Indigenous, the Indigenous patients were younger (50 years (IQR 39,60) vs 63 years (IQR 52,72), p<0.001), females (61% vs 41%, p=0.001), have higher prevalence of renal and cardiovascular disease and tend to have exudative effusion (93% vs 76%, p=0.032). Infections was judged to be the most common cause for effusion in both groups, more so among the Indigenous cohort. Effusion secondary to renal disease was higher (13% vs 1%, p<0.001) among Indigenous Australians, in contrast malignant effusions were higher (13% vs 4%, p=0.004) among non-Indigenous. Length of hospital stay was longer for Indigenous patients (p=0.001), and a greater proportion received renal dialysis (13% vs 1%, p<0.001). Intensive care unit (ICU) admissions rates were higher with infective etiology of pleural effusion (82% vs. 53% Indigenous & 44% vs. 39% non-Indigenous respectively). Re-presentations to hospital were higher among Indigenous patients (46% vs 33%, p=0.046) and were associated with renal and cardiac disease and malignancy in non-Indigenous.

CONCLUSION

There are significant differences in the way pleural effusion manifests among Australian Indigenous patients. Understanding these differences may facilitate approaches to the management and to implement strategies to reduce morbidity and mortality in this population. This article is protected by copyright. All rights reserved.

Identification of Microbiome Etiology Associated With Drug Resistance in Pleural Empyema

Identification of the offending organism and appropriate antimicrobial therapy are crucial for treating empyema. Diagnosis of empyema is largely obscured by the conventional bacterial cultivation and PCR process that has relatively low sensitivity, leading to limited understanding of the etiopathogenesis, microbiology, and role of antibiotics in the pleural cavity. To expand our understanding of its pathophysiology, we have carried out a metagenomic snapshot of the pleural effusion from 45 empyema patients by Illumina sequencing platform to assess its taxonomic, and antibiotic resistome structure. Our results showed that the variation of microbiota in the pleural effusion is generally stratified, not continuous. There are two distinct microbiome clusters observed in the forty-five samples: HA-SA type and LA-SA type. The categorization is mostly driven by species composition: HA-SA type is marked by Staphylococcus aureus as the core species, with other enriched 6 bacteria and 3 fungi, forming a low diversity and highly stable microbial community; whereas the LA-SA type has a more diverse microbial community with a distinct set of bacterial species that are assumed to be the oral origin. The microbial community does not shape the dominant antibiotic resistance classes which were common in the two types, while the increase of microbial diversity was correlated with the increase in antibiotic resistance genes. The existence of well-balanced microbial symbiotic states might respond differently to pathogen colonization and drug intake. This study provides a deeper understanding of the pathobiology of pleural empyema and suggests that potential resistance genes may hinder the antimicrobial therapy of empyema.