Pleural ultrasound for clinicians

Pleural effusions identified by thoracic ultrasound predict poor quality of life in patients with acute decompensated heart failure

INTRODUCTION

Pleural effusion (PE) is a common manifestation of acute decompensated heart failure (ADHF); however, its influence on the quality of life (QoL) is unknown.

OBJECTIVES

To identify whether PE detected using thoracic ultrasound (TUS) is associated with poorer QoL in patients with ADHF and a reduced ejection fraction (≤40 %).

METHODS

We conducted a prospective, longitudinal, descriptive, observational, single-center study at a university hospital in Mexico. We included participants with a reduced left ventricular ejection fraction who were admitted for ADHF. We performed TUS and the Minnesota Living with Heart Failure Questionnaire (MLHFQ) within the first 48 h of hospitalization.

RESULTS

Forty patients with ADHF (30 males and 10 females; mean age, 51.24 ± 16.942 years) were included in this study. The participants were categorized into two groups: those with (n = 25, 62.5 %) or without (n = 15, 37.5 %) PE on TUS. We found a statistically significant association between the presence of PEs and a worse perception of QoL. The mean MLHFQ score in the group of patients with PEs was 40 points, compared to 12 points in the group without PEs (p < 0.001). Poorer QoL was associated with a higher quantity of pleural fluid, as evidenced by the greater number of intercostal spaces occupied by the PE (p < 0.001).

CONCLUSIONS

Patients with ADHF and a reduced ejection fraction who present with PE have a worse perception of QoL than patients without PE.

Ultrasonic Elastography-guided Pleural Biopsy for the Diagnosis of Pleural Effusion: A Multicenter Prospective Study of Diagnostic Test Performance

Rationale: The diagnostic yield of traditional ultrasound-guided pleural biopsy remains unsatisfactory, particularly when the pleural thickness is ⩽5 mm and/or no pleural nodules are detected. Pleural ultrasound elastography (UE) has a better diagnostic yield than traditional ultrasound for malignant pleural effusion (MPE). However, studies on UE-guided pleural biopsies are lacking. Objectives: To evaluate the feasibility and safety of UE-guided pleural biopsy. Methods: In this multicenter prospective single-arm trial, patients with pleural effusion whose pleural thickness was ⩽5 mm with no pleural nodules were enrolled between July 2019 and August 2021. The diagnostic yield of UE-guided pleural biopsy for pleural effusion and its sensitivity for detecting MPE were evaluated. Results: Ninety-eight patients (mean age, 62.4 ± 13.2 yr; 65 men) were prospectively enrolled. The diagnostic yield of UE-guided pleural biopsy for making any diagnosis was 92.9% (91/98), and its sensitivity for MPE was 88.7% (55/62). In addition, its sensitivity for pleural tuberculosis was 69.6% (16/23). The rate of postoperative chest pain was acceptable, and there was no pneumothorax. Conclusions: UE-guided pleural biopsy is a novel technique for diagnosing MPE with good diagnostic yield and sensitivity. Clinical trial registered with https://www.chictr.org.cn (ChiCTR2000033572).

Adverse events related to thoracentesis and chest tube insertion: evaluation of the national collection of subject safety incidents in Japan

PURPOSE

Thoracentesis and chest tube insertion are procedures commonly performed in routine clinical practice and are considered mandatory skills for all physicians. Adverse events secondary to these procedures have been widely reported; however, epidemiology data concerning life-threatening events associated with these procedures are lacking.

METHODS

We retrospectively analyzed data from the Japan Council for Quality Health Care open database regarding subject safety incidents involving thoracentesis and chest tube insertion. The adverse events extracted from the database included only events associated with thoracentesis and chest tube insertion reported between January 2010 and April 2020.

RESULTS

We identified 137 adverse events due to thoracentesis or chest tube insertion. Our analysis also revealed at least 15 fatal adverse events and 17 cases of left/right misalignment. Not only resident doctors but also physicians with 10 years or more of clinical experience had been mentioned in these reports. The most common complications due to adverse events were lung injury (55%), thoracic vascular injury (21%), and liver injury (10%). Surgical treatment was required for 43 (31%) of the 137 cases, and the mortality risk was significantly higher for thoracic vascular injury than for other complications (p = 0.02).

CONCLUSION

We identified at least 15 fatal adverse events and 17 cases of left/right misalignment over a 10-year period in the Japan Council for Quality Health Care open database. Our findings also suggest that care should be taken to avoid thoracic vascular injury during chest tube insertion and that immediate intervention is required should such an injury occur.

[Thoracentesis in Primary Care]

Thoracentesis is a simple test with few complications that provides relevant information in the diagnosis of a pleural effusion, through a correct interpretation of the pleural fluid analysis. An interesting initiative would be to incorporate this technique by those Primary Care teams that treat serious and complex patients, with difficulties in moving to specialised centres far from their homes. In this context, a good knowledge of the diagnostic possibilities offered by the pleural fluid analysis could be very useful in the hands of well trained staff to establish the aetiology of a pleural effusion and be able to initiate, as quickly as possible, its treatment. This article aims to contribute to this, by suggesting guidelines on how a simple technique can provide relevant information in order to determine the aetiology of pleural effusion, and which could be implemented within a given Primary Care framework.

Competence in thoracic ultrasound

Ultrasound examination is traditionally considered a safe and repeatable exam, but its use is highly operator-dependent. Because of this, lack of sufficient operator skills could lead to diagnostic errors and damage to patient safety related to unnecessary tests or interventional procedures. The indications for lung ultrasound include: diagnosis, quantification, and follow-up of different conditions for which acute respiratory failure or chest pain are the main clinical presentation. Clinicians should have theoretical and practical knowledge on: physics and technology of ultrasound, indications and methodology of ultrasound examination, normal thoracic anatomy identification by echography, and detection of signs of pleuro-pulmonary pathology. Consequently, according to international recommendations, core basic skills and minimum training recommendations for the practice of medical ultrasound and image acquisition are needed to ensure competence of clinicians using ultrasound.

New insights in the use of pleural ultrasonography for diagnosis and treatment of pleural disease

The use of transthoracic ultrasound (US) has acquired a wide consensus among respiratory physicians during the last few years. The development of portable devices promotes patient's bedside evaluation providing rapid, real-time and low-cost diagnostic information. The different acoustic impedance between different tissues and organs produces artifacts known as A lines, B lines, sliding sign, lung point, etc. The identification of such artifacts is essential to discriminate normal pleural appearance from the presence of pleural effusion, pneumothorax, thickenings and tumors. Ultrasounds are also a valuable tool during interventional procedures, such as thoracentesis, chest tube insertion and transcutaneous biopsy. Its use is recommended before medical thoracoscopy in order to assess the best site of trocar insertion according to presence, quantity and characteristics of pleural effusion. The aim of this review is to provide practical tips on chest ultrasound in clinical and interventional respiratory practice.

Development and validation of a scoring system for the identification of pleural exudates of cardiac origin

BACKGROUND

Light's criteria misclassify about 30% of cardiac effusions as exudates, possibly leading to unnecessary testing. Our purpose was to derive and validate a scoring model to effectively identify these falsely categorized cardiac effusions, in the setting of natriuretic peptide lacking data.

METHODS

We retrospectively analyzed data from 3182 patients with exudative pleural effusions based on Light's criteria, of whom 276 had heart failure (derivation set). A scoring model was generated with those variables identified as independent predictors of cardiac effusions in a logistic regression analysis, and further evaluated in an independent population of 1165 patients.

RESULTS

The score consisted of age ≥75years (3 points), albumin gradient >1.2g/dL (3 points), pleural fluid lactate dehydrogenase <250U/L (2 points), bilateral effusions on chest radiograph (2 points), and protein gradient >2.5g/dL (1 point). At the best cutoff of ≥7 points, the score yielded 92% diagnostic accuracy, a likelihood ratio positive of 12.7 and a likelihood ratio negative of 0.39 for labeling cardiac effusions in the derivation sample. The respective figures in the validation sample were 87%, 6.5 and 0.33. Notably, the score had higher discriminatory properties than protein and albumin gradients in both the derivation (respective area under the curve - AUC - of 0.925, 0.825, and 0.801) and validation (respective AUC of 0.908 0.862 and 0.802; all p≤0.01) cohorts.

CONCLUSIONS

A simple scoring system can assist clinicians in accurately identifying false cardiac exudates when natriuretic peptides are not available.

Chest imaging for the diagnosis of complicated parapneumonic effusions

PURPOSE OF REVIEW

To provide an overview of the contribution of thoracic ultrasound (TUS) and computed tomography (CT) in the identification of complicated parapneumonic effusions (CPPE), defined as those which need chest tube drainage for resolution.

RECENT FINDINGS

A recent retrospective study found that visualization of complex (nonanechoic) effusions on TUS (likelihood ratio positive = 6.92) outperformed the recognition of loculated/septated effusions on CT (likelihood ratio = 2.20) or chest radiographs (likelihood ratio = 1.54) for predicting a CPPE. In another retrospective study, a weighted CT scoring system consisting of pleural contrast enhancement (three points), pleural microbubbles, increased extrapleural fat attenuation, and fluid volume at least 400 ml (one point each) had relatively good accuracy for labeling CPPE (likelihood ratio positive = 3.4; likelihood ratio negative = 0.22) when four or more points were achieved.

SUMMARY

Although a gold standard for CPPE diagnosis is lacking, bedside TUS primarily, and CT scan in certain circumstances, may help to drive clinical decisions regarding chest tube placement in parapneumonic effusions (PPE). However, recommendations are limited by the absence of prospective trials.

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.

Chest Tube Drainage of the Pleural Space: A Concise Review for Pulmonologists

Chest tube insertion is a common procedure usually done for the purpose of draining accumulated air or fluid in the pleural cavity. Small-bore chest tubes (≤14F) are generally recommended as the first-line therapy for spontaneous pneumothorax in non-ventilated patients and pleural effusions in general, with the possible exception of hemothoraces and malignant effusions (for which an immediate pleurodesis is planned). Large-bore chest drains may be useful for very large air leaks, as well as post-ineffective trial with small-bore drains. Chest tube insertion should be guided by imaging, either bedside ultrasonography or, less commonly, computed tomography. The so-called trocar technique must be avoided. Instead, blunt dissection (for tubes >24F) or the Seldinger technique should be used. All chest tubes are connected to a drainage system device: flutter valve, underwater seal, electronic systems or, for indwelling pleural catheters (IPC), vacuum bottles. The classic, three-bottle drainage system requires either (external) wall suction or gravity (“water seal”) drainage (the former not being routinely recommended unless the latter is not effective). The optimal timing for tube removal is still a matter of controversy; however, the use of digital drainage systems facilitates informed and prudent decision-making in that area. A drain-clamping test before tube withdrawal is generally not advocated. Pain, drain blockage and accidental dislodgment are common complications of small-bore drains; the most dreaded complications include organ injury, hemothorax, infections, and re-expansion pulmonary edema. IPC represent a first-line palliative therapy of malignant pleural effusions in many centers. The optimal frequency of drainage, for IPC, has not been formally agreed upon or otherwise officially established.

Involvement of systemic venous congestion in heart failure

Systemic venous congestion has gained significant importance in the interpretation of the pathophysiology of acute heart failure, especially in the development of renal function impairment during exacerbations. In this study, we review the concept, clinical characterisation and identification of venous congestion. We update current knowledge on its importance in the pathophysiology of acute heart failure and its involvement in the prognosis. We pay special attention to the relationship between abdominal congestion, the pulmonary interstitium as filtering membrane, inflammatory phenomena and renal function impairment in acute heart failure. Lastly, we review decongestion as a new therapeutic objective and the measures available for its assessment.