Ultrasound lung comets for the differential diagnosis of acute cardiogenic dyspnoea: A comparison with natriuretic peptides☆

Dynamic trend of lung fluid movement during exercise in heart failure: From lung imaging to alveolar-capillary membrane function

BACKGROUND

In chronic heart failure (HF), exercise-induced increase in pulmonary capillary pressure may cause an increase of pulmonary congestion, or the development of pulmonary oedema. We sought to assess in HF patients the exercise-induced intra-thoracic fluid movements, by measuring plasma brain natriuretic peptide (BNP), lung comets and lung diffusion for carbon monoxide (DLCO) and nitric oxide (DLNO), as markers of hemodynamic load changes, interstitial space and alveolar-capillary membrane fluids, respectively.

METHODS AND RESULTS

Twenty-four reduced ejection fraction HF patients underwent BNP, lung comets and DLCO/DLNO measurements before, at peak and 1 h after the end of a maximal cardiopulmonary exercise test. BNP significantly increased at peak from 549 (328-841) to 691 (382-1207, p < 0.0001) pg/mL and almost completely returned to baseline value 1 h after exercise. Comets number increased at peak from 9.4 ± 8.2 to 24.3 ± 16.7, returning to baseline (9.7 ± 7.4) after 1 h (p < 0.0001). DLCO did not change significantly at peak (from 18.01 ± 4.72 to 18.22 ± 4.73 mL/min/mmHg), but was significantly reduced at 1 h (16.97 ± 4.26 mL/min/mmHg) compared to both baseline (p = 0.0211) and peak (p = 0.0174). DLNO showed a not significant trend toward lower values 1 h post-exercise.

CONCLUSIONS

Moderate/severe HF patients have a 2-step intra-thoracic fluid movement with exercise: the first during active exercise, from the vascular space toward the interstitial space, as confirmed by comets increase, without any effect on diffusion, and the second, during recovery, toward the alveolar-capillary membrane, clearing the interstitial space but worsening gas diffusion.

Advances in heart failure management

Heart failure is a pathological condition characterized by substantial prevalence and mortality, particularly in the Western world. Over recent decades, both pharmacological and non-pharmacological interventions have emerged, significantly enhancing patient survival and overall quality of life. Moreover, advancements in diverse imaging modalities facilitate precise diagnosis and comprehensive investigation into the fundamental etiology, enabling the development of more precise therapeutic approaches. Nonetheless, discernible gaps persist in comprehending specific facets of this condition, albeit persistent research endeavors seek to elucidate these inquiries.

Transfer Learning-Based B-Line Assessment of Lung Ultrasound for Acute Heart Failure

OBJECTIVE

B-lines assessed by lung ultrasound (LUS) outperform physical exam, chest radiograph, and biomarkers for the associated diagnosis of acute heart failure (AHF) in the emergent setting. The use of LUS is however limited to trained professionals and suffers from interpretation variability. The objective was to utilize transfer learning to create an AI-enabled software that can aid novice users to automate LUS B-line interpretation.

METHODS

Data from an observational AHF LUS study provided standardized cine clips for AI model development and evaluation. A total of 49,952 LUS frames from 30 patients were hand scored and trained on a convolutional neural network (CNN) to interpret B-lines at the frame level. A random independent evaluation set of 476 LUS clips from 60 unique patients assessed model performance. The AI models scored the clips on both a binary and ordinal 0-4 multiclass assessment.

RESULTS

A multiclassification AI algorithm had the best performance at the binary level when applied to the independent evaluation set, AUC of 0.967 (95% CI 0.965-0.970) for detecting pathologic conditions. When compared to expert blinded reviewer, the 0-4 multiclassification AI algorithm scale had a reported linear weighted kappa of 0.839 (95% CI 0.804-0.871).

CONCLUSIONS

The multiclassification AI algorithm is a robust and well performing model at both binary and ordinal multiclass B-line evaluation. This algorithm has the potential to be integrated into clinical workflows to assist users with quantitative and objective B-line assessment for evaluation of AHF.

A machine learning-based lung ultrasound algorithm for the diagnosis of acute heart failure

Lung ultrasound (LUS) is an effective tool for diagnosing acute heart failure (AHF). However, several imaging protocols currently exist and how to best use LUS remains undefined. We aimed at developing a lung ultrasound-based model for AHF diagnosis using machine learning. Random forest and decision trees were generated using the LUS data (via an 8-zone scanning protocol) in patients with acute dyspnea admitted to the Emergency Department (PLUME study, N = 117) and subsequently validated in an external dataset (80 controls from the REMI study, 50 cases from the Nancy AHF cohort). Using the random forest model, total B-line sum (i.e., in both hemithoraces) was the most significant variable for identifying AHF, followed by the difference in B-line sum between the superior and inferior lung areas. The decision tree algorithm had a good diagnostic accuracy [area under the curve (AUC) = 0.865] and identified three risk groups (i.e., low 24%, high 70%, and very high-risk 96%) for AHF. The very high-risk group was defined by the presence of 14 or more B-lines in both hemithoraces while the high-risk group was described as having either B-lines mostly localized in superior points or in the right hemithorax. Accuracy in the validation cohort was excellent (AUC = 0.906). Importantly, adding the algorithm on top of a validated clinical score and classical definition of positive LUS scanning for AHF resulted in a significant improvement in diagnostic accuracy (continuous net reclassification improvement = 1.21, P < 0.001). Our simple lung ultrasound-based machine learning algorithm features an excellent performance and may constitute a validated strategy to diagnose AHF.

Role of NT-proBNP and lung ultrasound in diagnosing and classifying heart failure in a hospitalized oldest-old population: a cross-sectional study

AIM

Diagnosing and classifying heart failure (HF) in the oldest-old patients has technical and interpretation issues, especially in the acute setting. We assessed the usefulness of both N-terminal pro-brain natriuretic peptide (NT-proBNP) and lung ultrasound (LUS) for confirming HF diagnosis and predicting, among hospitalized HF patients, those with reduced ejection fraction (HFrEF).

METHODS

We performed a cross-sectional study on 148 consecutive patients aged ≥ 80 years admitted to our Internal Medicine and Geriatrics ward with at least one symptom/sign compatible with HF and NT-proBNP ≥ 125 pg/mL. We measured serum NT-proBNP levels and performed LUS and transthoracic echocardiography (TTE) on admission before diuretic therapy. We divided our cohort into three subgroups according to the left ventricular ejection fraction (LVEF): reduced (LVEF ≤ 40%), mildly-reduced (LVEF = 41-49%) and preserved (LVEF ≥ 50%).

RESULTS

The mean age was 88±5 years. Male prevalence was 42%. Patients with HFrEF were 19%. Clinical features and laboratory parameters did not differ between the three subgroups, except for higher NT-proBNP in HFrEF patients, which also had a higher number of total B-lines and intercostal spaces of pleural effusion at LUS. Overall, NT-proBNP showed an inverse correlation with LVEF (r = -0.22, p = 0.007) and a direct correlation with age, total pulmonary B-lines, and intercostal spaces of pleural effusion. According to the ROCs, NT-proBNP levels, pulmonary B-lines and pleural effusion extension were poorly predictive for HFrEF. The best-performing cut-offs were 9531 pg/mL for NT-proBNP (SP 0.70, SE 0.50), 13 for total B-lines (SP 0.69, SE 0.85) and one intercostal space for pleural effusion (SP 0.55, SE 0.89). Patients with admission NT-proBNP ≥ 9531 pg/mL had a 2-fold higher risk for HFrEF (OR 2.5, 95% CI 1.3-4.9), while we did not find any association for total B-lines ≥ 13 or pleural effusion ≥ 1 intercostal space with HFrEF. A significant association with HFrEF emerged for the combination of NT-proBNP ≥ 9531 pg/mL, total B-lines ≥ 13 and intercostal spaces of pleural effusion ≥ 1 (adjusted OR 4.3, 95% CI 1.5-12.9).

CONCLUSIONS

Although NT-proBNP and LUS help diagnose HF, their accuracy in discriminating HFrEF from non-HFrEF was poor in our real-life clinical study on oldest-old hospitalized patients, making the use of TTE still necessary to distinguish HF phenotypes in this peculiar setting. These data require confirmation in more extensive and longer prospective studies.

The Importance of Lung Ultrasound and IGFBP7 (Insulin-like Growth Factor Binding Protein 7) Assessment in Diagnosing Patients with Heart Failure

Background: In daily practice, there are problems with adequately diagnosing the cause of dyspnea in patients with heart failure with preserved and mildly reduced ejection fractions (HFpEF and HFmrEF). This study aimed to assess the usefulness of lung ultrasound in diagnosing HFpEF and HFmrEF and determine its correlation with IGFBP7 (insulin-like growth factor binding protein 7), NTproBNP (N-terminal pro-B-type natriuretic peptide), and echocardiographic markers. Methods: The research was conducted on 143 patients hospitalized between 2018 and 2020, admitted due to dyspnea, and diagnosed with HFpEF and HFmrEF. Venous blood was collected from all participants to obtain basic biochemical parameters, NTproBNP, and IGFBP7. Moreover, all participants underwent echocardiography and transthoracic lung ultrasound. Two years after hospitalization a follow-up telephone visit was performed. Results: The number of B-lines in the LUS ≥ 16 was determined with a sensitivity of-73% and specificity of-62%, indicating exacerbation of heart failure symptoms on admission. The number of B-lines ≥ 14 on admission was determined as a cut-off point, indicating an increased risk of death during the 2-year follow-up period. The factors that significantly impacted mortality in the study patient population were age and the difference between the number of B-lines on ultrasound at admission and at hospital discharge. IGFBP7 levels had no significant effect on the duration of hospitalization, risk of rehospitalization, or mortality during follow-up. Conclusions: Lung ultrasonography provides additional diagnostic value in patients with HFpEF or HFmrEF and exacerbation of heart failure symptoms. The number of B-lines ≥ 14 may indicate an increased risk of death.

Congestion in Heart Failure: From the Secret of a Mummy to Today's Novel Diagnostic and Therapeutic Approaches: A Comprehensive Review

This review paper presents a review of the evolution of this disease throughout the centuries, describes and summarizes the pathophysiologic mechanisms, briefly discusses the mechanism of action of diuretics, presents their role in decongesting heart failure in patients, and reveals the data behind ultrafiltration in the management of acutely or chronically decompensated heart failure (ADHF), focusing on all the available data and advancements in this field. Acutely decompensated heart failure (ADHF) presents a critical clinical condition characterized by worsening symptoms and signs of heart failure, necessitating prompt intervention to alleviate congestion and improve cardiac function. Diuretics have traditionally been the mainstay for managing fluid overload in ADHF. Mounting evidence suggests that due to numerous causes, such as coexisting renal failure or chronic use of loop diuretics, an increasing rate of diuretic resistance is noticed and needs to be addressed. There has been a series of trials that combined diuretics of different categories without the expected results. Emerging evidence suggests that ultrafiltration may offer an alternative or adjunctive approach.

Noninvasive Imaging Methods for Quantification of Pulmonary Edema and Congestion: A Systematic Review

Quantification of pulmonary edema and congestion is important to guide diagnosis and risk stratification, and to objectively evaluate new therapies in heart failure. Herein, we review the validation, diagnostic performance, and clinical utility of noninvasive imaging modalities in this setting, including chest x-ray, lung ultrasound (LUS), computed tomography (CT), nuclear medicine imaging methods (positron emission tomography [PET], single photon emission CT), and magnetic resonance imaging (MRI). LUS is a clinically useful bedside modality, and fully quantitative methods (CT, MRI, PET) are likely to be important contributors to a more accurate and precise evaluation of new heart failure therapies and for clinical use in conjunction with cardiac imaging. There are only a limited number of studies evaluating pulmonary congestion during stress. Taken together, noninvasive imaging of pulmonary congestion provides utility for both clinical and research assessment, and continued refinement of methodologic accuracy, validation, and workflow has the potential to increase broader clinical adoption.

Point-of-Care Thoracic Ultrasound in Children: New Advances in Pediatric Emergency Setting

Point-of-care thoracic ultrasound at the patient's bedside has increased significantly recently, especially in pediatric settings. Its low cost, rapidity, simplicity, and repeatability make it a practical examination to guide diagnosis and treatment choices, especially in pediatric emergency departments. The fields of application of this innovative imaging method are many and include primarily the study of lungs but also that of the heart, diaphragm, and vessels. This manuscript aims to describe the most important evidence for using thoracic ultrasound in the pediatric emergency setting.

Pulmonary Congestion on Lung Ultrasound Predicts Increased Risk of 30-Day Readmission in Heart Failure Patients

OBJECTIVES

Heart failure exacerbations are a common cause of hospitalizations with a high readmission rate. There are few validated predictors of readmission after treatment for acute decompensated heart failure (ADHF). Lung ultrasound (LUS) is sensitive and specific in the assessment of pulmonary congestion; however, it is not frequently utilized to assess for congestion before discharge. This study assessed the association between number of B-lines, on LUS, at patient discharge and risk of 30-day readmission in patients hospitalized for acute decompensated heart failure (ADHF).

METHODS

This was a single-center prospective study of adults admitted to a quaternary care center with a diagnosis of ADHF. At the time of discharge, the patient received an 8-zone LUS exam to evaluate for the presence of B-lines. A zone was considered positive if ≥3 B-lines was present. We assessed the risk of 30-day readmission associated with the number of lung zones positive for B-lines using a log-binomial regression model.

RESULTS

Based on data from 200 patients, the risk of 30-day readmission in patients with 2-3 positive lung zones was 1.25 times higher (95% CI: 1.08-1.45), and in patients with 4-8 positive lung zones was 1.50 times higher (95% CI: 1.23-1.82, compared with patients with 0-1 positive zones, after adjusting for discharge blood urea nitrogen, creatinine, and hemoglobin.

CONCLUSION

Among patients admitted with ADHF, the presence of B-lines at discharge was associated with a significantly increased risk of 30-day readmission, with greater number of lung zones positive for B-lines corresponding to higher risk.

Lung ultrasound in the diagnosis of COVID-19-associated pneumonia

Over the past decades, lung ultrasound in the diagnosis of lung diseases has become widespread. Ultrasound examination has a number of advantages (no radiation exposure, real-time imaging, clear visualization of the subpleural lung regions and costophrenic angles), which make it possible to use ultrasound to monitor the dynamics of pneumonia in children and pregnant women. Currently, in the context of the COVID-19 pandemic, lung ultrasound is widely used due to its high diagnostic efficiency, which is comparable with classical radiography and X-ray computed tomography (CT) by a number of parameters.

The article describes the method of lung ultrasound and the radiographic pattern of COVID-19-associated pneumonia. It also provides a review of the literature, according to which the severity of pneumonia was determined, depending on the radiographic pattern, and the need for a lung ultrasound was identified.

The article indicates that information on assessment of the radiographic pattern of the lungs at runtime in different variants of the course of coronavirus infection, as well as many methodological issues, including the frequency of second-look lung ultrasound, has not been sufficiently studied.

MONITORING OF PULMONARY EDEMA USING ULTRASOUND RADIOFREQUENCY SIGNAL

ABSTRACT

Objectives: Excessive accumulation of extravascular lung water impairs respiratory gas exchange and results in respiratory distress. Real-time radiofrequency signals of ultrasound can continuously and quantitatively monitor excessive lung water. This study aims to evaluate the availability of continuous real-time quantitative pulmonary edema monitoring using ultrasound radiofrequency signals and compare it with Pa o2 (partial pressure of arterial oxygen)/F io2 (fraction of inspired oxygen) (PF) ratio, conventional lung ultrasound, and the Hounsfield unit of chest computed tomography. Methods: Male Yorkshire pigs (40.5 ± 0.5 kg) were anesthetized and mechanically ventilated. A balanced crystalloid was administered to induce hydrostatic pulmonary edema. Three different infusion rates of 2, 4, and 6 mL/kg per minute were tested to determine the infusion rate for the appropriate swine model. The chest computed tomography and ultrasonography with radiofrequency signals were taken every 5 min during the full inspiration. The ultrasonography scans with radiofrequency signals were measured at the intercostal space where the line crossing the two armpits and the right anterior axillary line intersected. Results: The infusion rate of fluid for the pulmonary edema model was determined to be 6 mL/kg per minute, and a total of four pigs were tested at an injection rate of 6 mL/kg. The adjusted R2 values of regression analysis between the radiofrequency signal and computer tomography Hounsfield score were 0.990, 0.993, 0.988, and 0.993 (all P values <0.05). All radiofrequency signal changes preceded changes in PF ratio or lung ultrasound changes. The area under the receiver operating characteristic curve of the radiofrequency signal for predicting PF ratio <300 was 0.88 (95% confidence interval, 0.82-0.93). Conclusion: We evaluated ultrasound radiofrequency signals to assess pulmonary edema in a swine model that can worsen gradually and showed that quantitative ultrasound radiofrequency signal analysis could assess pulmonary edema and its progression before PF ratio or lung ultrasound changes.

Lung Ultrasound in Coronary Care Unit, an Important Diagnostic Tool for Concomitant Pneumonia

Background: In the setting of a coronary care unit (CCU), the early detection of pneumonia is of paramount important to prevent severe complications. This study was designed aiming to evaluate the diagnostic accuracy of lung ultrasound (LUS) in the detection of pneumonia and compared with chest X-ray (CXR). Method: We enrolled 110 consecutive patients admitted to the CCU of Federico II University Hospital. Each patient underwent CXR and bedside LUS on admission. The final diagnosis (pneumonia vs. no pneumonia) was established by another clinician reviewing clinical and laboratory data independent of LUS results and possibly prescribing chest contrast-enhanced CT (n = 34). Results: The mean age was 70 ± 11 years old, and 68% were males. Pneumonia was clinically diagnosed in 26 (23%) patients. LUS was positive for pneumonia in 24 patients (sensitivity 92%, specificity 81%). Chest radiography was positive for pneumonia in nine patients (sensitivity 43%, specificity 95%). Using CT scan as a reference, LUS exhibited 92% sensitivity and a specificity of 96%. In ROC curve analysis, the diagnostic accuracy of CXR and LUS for the diagnosis of pneumonia was 0.86 (95% CI 0.77−0.94), which was higher than CXR 0.68 (95% CI 0.55−0.84), p < 0.05. Conclusion: Based on the findings of the present study, the accuracy of LUS in the detection of pneumonia was significantly higher than chest X-ray with comparable sensibility to CT scan.

POCUS in dyspnea, nontraumatic hypotension, and shock; a systematic review of existing evidence

BACKGROUND

Point-of-care ultrasound (POCUS) has been adopted as a powerful tool in acute medicine. This systematic review aims to critically appraise the existing literature on point-of-care ultrasound in respiratory or circulatory deterioration.

METHODS

Original studies on POCUS and dyspnea, nontraumatic hypotension, and shock from March 2002 until March 2022 were assessed in the PubMed and Embase Databases. Two reviewers independently screened articles for inclusion, extracted data, and assessed the quality of included studies using an established checklist.

RESULTS

We included 89 articles in this review. Point-of-care ultrasound in the initial workup increases the diagnostic accuracy in patients with dyspnea, nontraumatic hypotension and shock in the ED, ICU and medical ward setting. No improvement is found in patients with severe sepsis in the ICU setting. POCUS is capable of narrowing the differential diagnoses and is faster, and more feasible in the acute setting than other diagnostics available. Results on outcome measures are heterogenous. The quality of the included studies is considered low most of the times, mainly because of performance and selection bias and absence of a gold standard as the reference test.

CONCLUSION

We conclude that POCUS contributes to a higher diagnostic accuracy in dyspnea, nontraumatic hypotension, and shock. It aides in narrowing the differential diagnoses and shortening the time to correct diagnosis and effective treatment.

TRIAL REGISTRY

INPLASY; Registration number: INPLASY202220020; URL: https://inplasy.com/.

Development and validation of a decision support tool for the diagnosis of acute heart failure: systematic review, meta-analysis, and modelling study

OBJECTIVES

To evaluate the diagnostic performance of N-terminal pro-B-type natriuretic peptide (NT-proBNP) thresholds for acute heart failure and to develop and validate a decision support tool that combines NT-proBNP concentrations with clinical characteristics.

DESIGN

Individual patient level data meta-analysis and modelling study.

SETTING

Fourteen studies from 13 countries, including randomised controlled trials and prospective observational studies.

PARTICIPANTS

Individual patient level data for 10 369 patients with suspected acute heart failure were pooled for the meta-analysis to evaluate NT-proBNP thresholds. A decision support tool (Collaboration for the Diagnosis and Evaluation of Heart Failure (CoDE-HF)) that combines NT-proBNP with clinical variables to report the probability of acute heart failure for an individual patient was developed and validated.

MAIN OUTCOME MEASURE

Adjudicated diagnosis of acute heart failure.

RESULTS

Overall, 43.9% (4549/10 369) of patients had an adjudicated diagnosis of acute heart failure (73.3% (2286/3119) and 29.0% (1802/6208) in those with and without previous heart failure, respectively). The negative predictive value of the guideline recommended rule-out threshold of 300 pg/mL was 94.6% (95% confidence interval 91.9% to 96.4%); despite use of age specific rule-in thresholds, the positive predictive value varied at 61.0% (55.3% to 66.4%), 73.5% (62.3% to 82.3%), and 80.2% (70.9% to 87.1%), in patients aged <50 years, 50-75 years, and >75 years, respectively. Performance varied in most subgroups, particularly patients with obesity, renal impairment, or previous heart failure. CoDE-HF was well calibrated, with excellent discrimination in patients with and without previous heart failure (area under the receiver operator curve 0.846 (0.830 to 0.862) and 0.925 (0.919 to 0.932) and Brier scores of 0.130 and 0.099, respectively). In patients without previous heart failure, the diagnostic performance was consistent across all subgroups, with 40.3% (2502/6208) identified at low probability (negative predictive value of 98.6%, 97.8% to 99.1%) and 28.0% (1737/6208) at high probability (positive predictive value of 75.0%, 65.7% to 82.5%) of having acute heart failure.

CONCLUSIONS

In an international, collaborative evaluation of the diagnostic performance of NT-proBNP, guideline recommended thresholds to diagnose acute heart failure varied substantially in important patient subgroups. The CoDE-HF decision support tool incorporating NT-proBNP as a continuous measure and other clinical variables provides a more consistent, accurate, and individualised approach.

STUDY REGISTRATION

PROSPERO CRD42019159407.

Prognostic Value of Lung Ultrasound in Aortic Stenosis

Background: Aortic stenosis (AS) is the most common primary valve lesion requiring intervention in Europe and North America. It has a prolonged subclinical period during which, as AS worsens, left ventricular adaptation becomes inadequate and impaired systolic and/or diastolic dysfunction may lead to overt heart failure (HF). The development of HF is an inflexion point in the natural history of AS. Pulmonary congestion is a cardinal feature in HF, and lung ultrasound (LUS) evaluation of B-lines has been proposed as a simple, noninvasive tool to assess pulmonary congestion.

Aim: To assess the presence and the prognostic value of sonographic pulmonary congestion in patients with moderate or severe AS.

Methods: 75 consecutive patients (39 women, mean age 73.85 ± 7.7 years) with moderate or severe AS were enrolled. All patients underwent comprehensive echocardiography and LUS with the 28 scanning-site assessment. Patients were followed-up for 13.4 ± 6 months to establish the prognostic value of LUS. A composite endpoint of death (of any cause), hospitalization for HF and intensification of loop diuretic therapy was considered.

Results: We found a severe degree of B-lines (≥30) in 29.33% of patients. The number of B-lines correlated with the estimated pulmonary artery systolic pressure (p < 0.001, r = 0.574) and increased along with NYHA class (p < 0.05, rho = 0.383). At multivariable analysis, B-lines ≥30, and mean gradient were the independent predictors of events [B-lines: 2.79 (CI 1.03–7.54), p = 0.04; mean gradient: 1.04 (CI 1.01–1.07), p = 0.004].

Conclusion: Evaluation of B-lines is a simple, highly feasible method to detect pulmonary congestion in AS. The number of B-lines correlates with the hemodynamic changes caused by AS and with the functional status of patients. A severe degree of sonographic pulmonary congestion is associated with an increased risk of adverse events.

The Prognostic Value of Lung Ultrasound in Patients With Newly Diagnosed Heart Failure With Preserved Ejection Fraction in the Ambulatory Setting

Background: Heart failure with preserved ejection fraction (HFpEF) is a growing healthcare burden, and its prevalence is steadily increasing. Lung ultrasound (LUS) is a promising screening and prognostic tool in the heart failure population. However, more information on its value in predicting outcome is needed.

Aims: The aim of our study was to assess the prognostic performance of LUS B-lines compared to traditional and novel clinical and echocardiographic parameters and natriuretic peptide levels in patients with newly diagnosed HFpEF in an ambulatory setting.

Methods: In our prospective cohort study, all ambulatory patients with clinical suspicion of HFpEF underwent comprehensive echocardiography, lung ultrasound and NT-proBNP measurement during their first appointment at our cardiology outpatient clinic. Our endpoint was a composite of worsening heart failure symptoms requiring hospitalization or loop diuretic dose escalation and death.

Results: We prospectively enrolled 75 consecutive patients with HFpEF who matched our inclusion and exclusion criteria. We detected 11 events on a 26 ± 10-months follow-up. We found that the predictive value of B-lines is similar to the predictive value of NT-proBNP (AUC 0.863 vs. 0.859), with the best cut-off at >15 B-lines. Having more B-lines than 15 significantly increased the likelihood of adverse events with a hazard ratio of 20.956 (p = 0.004). The number of B-lines remained an independent predictor of events at multivariate modeling. Having more than 15 B-lines lines was associated with a significantly worse event-free survival (Log-rank: 16.804, p < 0.001).

Conclusion: The number of B-lines seems to be an independent prognostic factor for adverse outcomes in HFpEF. Since it is an easy-to-learn, feasible and radiation-free method, it may add substantial value to the commonly used diagnostic and risk stratification models.

Classification of Lung Disease in Children by Using Lung Ultrasound Images and Deep Convolutional Neural Network

Bronchiolitis is the most common cause of hospitalization of children in the first year of life and pneumonia is the leading cause of infant mortality worldwide. Lung ultrasound technology (LUS) is a novel imaging diagnostic tool for the early detection of respiratory distress and offers several advantages due to its low-cost, relative safety, portability, and easy repeatability. More precise and efficient diagnostic and therapeutic strategies are needed. Deep-learning-based computer-aided diagnosis (CADx) systems, using chest X-ray images, have recently demonstrated their potential as a screening tool for pulmonary disease (such as COVID-19 pneumonia). We present the first computer-aided diagnostic scheme for LUS images of pulmonary diseases in children. In this study, we trained from scratch four state-of-the-art deep-learning models (VGG19, Xception, Inception-v3 and Inception-ResNet-v2) for detecting children with bronchiolitis and pneumonia. In our experiments we used a data set consisting of 5,907 images from 33 healthy infants, 3,286 images from 22 infants with bronchiolitis, and 4,769 images from 7 children suffering from bacterial pneumonia. Using four-fold cross-validation, we implemented one binary classification (healthy vs. bronchiolitis) and one three-class classification (healthy vs. bronchiolitis vs. bacterial pneumonia) out of three classes. Affine transformations were applied for data augmentation. Hyperparameters were optimized for the learning rate, dropout regularization, batch size, and epoch iteration. The Inception-ResNet-v2 model provides the highest classification performance, when compared with the other models used on test sets: for healthy vs. bronchiolitis, it provides 97.75% accuracy, 97.75% sensitivity, and 97% specificity whereas for healthy vs. bronchiolitis vs. bacterial pneumonia, the Inception-v3 model provides the best results with 91.5% accuracy, 91.5% sensitivity, and 95.86% specificity. We performed a gradient-weighted class activation mapping (Grad-CAM) visualization and the results were qualitatively evaluated by a pediatrician expert in LUS imaging: heatmaps highlight areas containing diagnostic-relevant LUS imaging-artifacts, e.g., A-, B-, pleural-lines, and consolidations. These complex patterns are automatically learnt from the data, thus avoiding hand-crafted features usage. By using LUS imaging, the proposed framework might aid in the development of an accessible and rapid decision support-method for diagnosing pulmonary diseases in children using LUS imaging.

The role of non-invasive devices for the telemonitoring of heart failure patients

Heart failure (HF) patients represent one of the most prevalent as well as one of the most fragile population encountered in the cardiology and internal medicine departments nowadays. Estimated to account for around 26 million people worldwide, diagnosed patients present a poor prognosis and quality of life with a clinical history accompanied by repeated hospital admissions caused by an exacerbation of their chronic condition. The frequent hospitalizations and the extended hospital stays mean an extremely high economic burden for healthcare institutions. Meanwhile, the number of chronically diseased and elderly patients is continuously rising, and a lack of specialized physicians is evident. To cope with this health emergency, more efficient strategies for patient management, more accurate diagnostic tools, and more efficient preventive plans are needed. In recent years, telemonitoring has been introduced as the potential answer to solve such needs. Different methodologies and devices have been progressively investigated for effective home monitoring of cardiologic patients. Invasive hemodynamic devices, such as CardioMEMS™, have been demonstrated to be reducing hospitalizations and mortality, but their use is however restricted to limited cases. The role of external non-invasive devices for remote patient monitoring, instead, is yet to be clarified. In this review, we summarized the most relevant studies and devices that, by utilizing non-invasive telemonitoring, demonstrated whether beneficial effects in the management of HF patients were effective.

Comparison of curvilinear-array (microconvex) and phased-array transducers for ultrasonography of the lungs in dogs

OBJECTIVES

To compare the use of curvilinear-array (microconvex) and phased-array transducers for ultrasonographic examination of the lungs in dogs.

ANIMALS

13 client-owned dogs with left-sided congestive heart failure.

PROCEDURES

In a prospective methods comparison study, 24 ultrasonographic examinations of the lungs (4 sites/hemithorax) were performed with both curvilinear-array and phased-array transducers at 3 clinical time points. Two observers independently assessed the number of B lines (scored per site and in total), number of sites strongly positive for B lines (ie, those with > 3 B lines/site), and image quality (scored on a 5-point scale). Analyses included assessment of interobserver agreement with κ analysis, comparison of quality scores between transducers with mixed-effects modeling, and investigation of agreement and bias for B-line data and quality scores between transducers with Passing-Bablok regression.

RESULTS

Interobserver agreement for total B-line scores and number of strong-positive sites was excellent (κ > 0.80) for both transducers. There was no evidence of analytic bias for the number of B lines or strong-positive sites between transducers. Interobserver agreement for image quality scores was moderate (κ, 0.498 and 0.517 for the curvilinear-array and phased-array transducers, respectively). Both observers consistently assigned higher-quality scores to curvilinear-array images than to phased-array images.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated both curvilinear-array (microconvex) and phased-array transducers can be used by experienced sonographers to obtain diagnostic ultrasonographic images of the lungs in dogs with acute or resolving left-sided congestive heart failure and suggested the former transducer may be preferred, particularly to aid identification of anatomic landmarks for orientation.

Evaluation of a survey for acute care programme directors on the utilisation of point-of-care ultrasound

PURPOSE

Point-of-care ultrasound (POCUS) is ultrasound brought to the patient's bedside and performed in 'real time' by the healthcare provider. The utility of POCUS to facilitate management of the acutely ill patient has been demonstrated for multiple pathologies. However, the integration of ultrasonography and echocardiography training into residency curriculum varies across the acute care specialties.

STUDY DESIGN

After an institutional review board approval, anaesthesiology, emergency medicine, family medicine, internal medicine, paediatrics and general surgery programme directors (PDs) were surveyed. The survey consisted of 11 questions evaluating the primary bedside assessment tool for common acute care situations, POCUS topics that the PDs were comfortable practising and topics that the PDs felt were useful for their specialty. Barriers to POCUS use, certification and documentation were also surveyed.

RESULTS

Overall, 270 PD surveys were completed. The preferred primary assessment tool for common acute care situations varied with specialty; emergency medicine PDs consistently responded that POCUS was the diagnostic modality of choice (p<0.0001). The majority of the PDs reported lack of educational opportunities as the primary barrier to learning POCUS (64%). Most PDs indicated that POCUS examinations should be documented (95.7%), and 39% reported that departmental certification would be sufficient.

CONCLUSIONS

This study is the first to evaluate differences in the preferred initial bedside assessment tool between the acute care specialties. Although POCUS is a superior tool for evaluating acute pathologies, disconnect between education and utilisation remains. This study highlights the need to incorporate POCUS into the acute care specialty curriculum.

Prognostic value of lung ultrasound in patients hospitalized for heart disease irrespective of symptoms and ejection fraction

Aims

Lung ultrasound B‐lines are the sonographic sign of pulmonary congestion and can be used in the differential diagnosis of dyspnoea to rule in or rule out acute heart failure (AHF). Our aim was to assess the prognostic value of B‐lines, integrated with echocardiography, in patients admitted to a cardiology department, independently of the initial clinical presentation, thus in patients with and without AHF, and in AHF with reduced and preserved ejection fraction (HFrEF and HFpEF).

Methods and results

We enrolled consecutive patients admitted for various cardiac conditions. Patients were classified into three groups: (i) acute HFrEF; (ii) acute HFpEF; and (iii) non‐AHF. All patients underwent an echocardiogram coupled with lung ultrasound at admission, according to standardized protocols. We followed up 1021 consecutive inpatients (69 ± 12 years) for a median of 14.4 months (interquartile range 4.6–24.3) for death and rehospitalization for AHF. During the follow‐up, 126 events occurred. Admission B‐lines > 30, ejection fraction < 50%, tricuspid regurgitation velocity > 2.8 m/s, and tricuspid annular plane systolic excursion < 17 mm were independent predictors at multivariable analysis. B‐lines > 30 had a strong predictive value in HFpEF and non‐AHF, but not in HFrEF.

Conclusions

Ultrasound B‐lines can detect subclinical pulmonary interstitial oedema in patients thought to be free of congestion and provide useful information not only for the diagnosis but also for the prognosis in different cardiac conditions. Their added prognostic value among standard echocardiographic parameters is more robust in patients with HFpEF compared with HFrEF.

Point-of-care lung ultrasound predicts in-hospital mortality in acute heart failure

BACKGROUND

B-lines have been associated with adverse clinical outcomes in patients with heart failure (HF) when found at hospital discharge or during outpatient visits. Whether lung ultrasound (LUS) assessed B-lines may predict in-hospital mortality in patients with acute HF is still undetermined.

AIM

To evaluate the association between B-lines on admission and in-hospital mortality among patients admitted with acute HF.

METHODS

Hand-held LUS was used to examine patients with acute HF. LUS was performed in eight chest zones with a pocket ultrasound device and analyzed offline. The association between B-lines and in-hospital mortality was assessed using Cox regression models.

RESULTS

We included 62 patients with median age 56 years, 69.4% men, and median left ventricle ejection fraction 25%. The sum of B-lines ranged from 0 to 53 (median 6.5). An optimal receiver operating characteristic-determined cut-off of ≥19 B-lines demonstrated a sensitivity of 57% and a specificity of 86% (area under the curve 0.788) for in-hospital mortality. The incremental prognostic value of LUS when compared with lung crackles or peripheral edema by integrated discrimination improvement was 12.96% (95% CI: 7.0-18.8, P = 0.02). Patients with ≥19 B-lines had a 4-fold higher risk of in-hospital mortality (HR 4.38; 95% CI: 1.37-13.95, P < 0.01).

CONCLUSION

In patients admitted with acute HF, point-of-care LUS measurements of pulmonary congestion (B-lines) are associated with in-hospital mortality.

Bedside noninvasive monitoring of mechanically ventilated patients

PURPOSE OF REVIEW

Among noninvasive lung imaging techniques that can be employed at the bedside electrical impedance tomography (EIT) and lung ultrasound (LUS) can provide dynamic, repeatable data on the distribution regional lung ventilation and response to therapeutic manoeuvres.In this review, we will provide an overview on the rationale, basic functioning and most common applications of EIT and Point of Care Ultrasound (PoCUS, mainly but not limited to LUS) in the management of mechanically ventilated patients.

RECENT FINDINGS

The use of EIT in clinical practice is supported by several studies demonstrating good correlation between impedance tomography data and other validated methods of assessing lung aeration during mechanical ventilation. Similarly, LUS also correlates with chest computed tomography in assessing lung aeration, its changes and several pathological conditions, with superiority over other techniques. Other PoCUS applications have shown to effectively complement the LUS ultrasound assessment of the mechanically ventilated patient.

SUMMARY

Bedside techniques - such as EIT and PoCUS - are becoming standards of the care for mechanically ventilated patients to monitor the changes in lung aeration, ventilation and perfusion in response to treatment and to assess weaning from mechanical ventilation.

Lung Ultrasound: Its Findings and New Applications in Neonatology and Pediatric Diseases

Lung ultrasound has become increasingly used in both adult and pediatric populations, allowing the rapid evaluation of many lung and pleura diseases. This popularity is due to several advantages of the method such as the low cost, rapidity, lack of ionizing radiation, availability of bedside and repeatability of the method. These features are even more important after the outbreak of the SARS-CoV-2 pandemic, given the possibility of recognizing through ultrasound the signs of interstitial lung syndrome typical of pneumonia caused by the virus. The purpose of this paper is to review the available evidence of lung ultrasound (LUS) in children and its main applications in pediatric diseases.

Bedside lung ultrasonography by emergency department residents as an aid for identifying heart failure in patients with acute dyspnea after a 2-h training course

BACKGROUND

Ultrasonographic B-lines have recently emerged as a bedside imaging tool for the differential diagnosis of acute dyspnea in the Emergency Department (ED). However, despite its simplicity, LUS has not fully penetrated emergency department. This study aimed to assess the accuracy and reproducibility of ultrasonographic B-lines performed by emergency medicine (EM) residents for the diagnosis of congestive heart failure (CHF) in patients admitted to ED for acute dyspnea.

PATIENTS AND METHODS

This is a cross-sectional prospective study conducted between January 2016 and October 2017 including patients aged over 18 years admitted to ED for acute dyspnea. At admission, two consecutive bedside LUS study were performed by a pair of EM residents who received a 2-h course for recognition of sonographic B-lines to determine independently B-lines score and B-profile pattern. All participating sonographers were blinded to patients' clinical data. B-lines score ≥ 15 or a B-profile pattern was considered as suggestive of CHF. The final leading diagnosis was assessed by two expert sonographers, who were blinded to the residents' interpretations, based on clinical findings, chest X-ray, brain natriuretic peptide, cardiac and lung ultrasound testing. Accuracy and agreement of B-lines score and B-profile pattern were calculated.

RESULTS

We included 700 patients with a mean age of 68 ± 12.6 years and a sex ratio (M/F) of 1.43. The diagnosis of CHF was recorded in 371 patients (53%). The diagnostic performance of B-lines score at a cut-off 15 and B-profile pattern was, respectively, 88% and 82.5% for sensitivity, 75% and 84% for specificity, 80% and 85% for positive predictive value, 84% and 81% for negative predictive value. The area under receiver operating characteristic curve was 0.86 [0.83-0.89] and 0.83 [0.80-0.86], respectively, for B-lines score and B-profile pattern. There was an excellent agreement between residents for the diagnosis of CHF using both scores (kappa = 0.81 and 0.85, respectively, for ordinal scale B-lines score and B-profile pattern).

CONCLUSION

Lung ultrasound B-lines assessment has a good accuracy and an excellent reproducibility in the diagnosis of CHF in the hand of EM residents following a short training program. Trial registration Name of the registry: clinicaltrials.gov; Trial registration number: NCT03717779; Date of registration: October 24, 2018 'Retrospectively registered'; URL of trial registry record: clinicaltrials.gov.

Second-order grey-scale texture analysis of pleural ultrasound images to differentiate acute respiratory distress syndrome and cardiogenic pulmonary edema

Discriminating acute respiratory distress syndrome (ARDS) from acute cardiogenic pulmonary edema (CPE) may be challenging in critically ill patients. Aim of this study was to investigate if gray-level co-occurrence matrix (GLCM) analysis of lung ultrasound (LUS) images can differentiate ARDS from CPE. The study population consisted of critically ill patients admitted to intensive care unit (ICU) with acute respiratory failure and submitted to LUS and extravascular lung water monitoring, and of a healthy control group (HCG). A digital analysis of pleural line and subpleural space, based on the GLCM with second order statistical texture analysis, was tested. We prospectively evaluated 47 subjects: 16 with a clinical diagnosis of CPE, 8 of ARDS, and 23 healthy subjects. By comparing ARDS and CPE patients' subgroups with HCG, the one-way ANOVA models found a statistical significance in 9 out of 11 GLCM textural features. Post-hoc pairwise comparisons found statistical significance within each matrix feature for ARDS vs. CPE and CPE vs. HCG (P ≤ 0.001 for all). For ARDS vs. HCG a statistical significance occurred only in two matrix features (correlation: P = 0.005; homogeneity: P = 0.048). The quantitative method proposed has shown high diagnostic accuracy in differentiating normal lung from ARDS or CPE, and good diagnostic accuracy in differentiating CPE and ARDS. Gray-level co-occurrence matrix analysis of LUS images has the potential to aid pulmonary edemas differential diagnosis.

Utility of point-of-care lung ultrasound for monitoring cardiogenic pulmonary edema in dogs

Background

Point‐of‐care lung ultrasound (LUS) is an effective tool to diagnose left‐sided congestive heart failure (L‐CHF) in dogs via detection of ultrasound artifacts (B‐lines) caused by increased lung water.

Hypothesis/Objectives

To determine whether LUS can be used to monitor resolution of cardiogenic pulmonary edema in dogs, and to compare LUS to other indicators of L‐CHF control.

Animals

Twenty‐five client‐owned dogs hospitalized for treatment of first‐onset L‐CHF.

Methods

Protocolized LUS, thoracic radiographs (TXR), and plasma N‐terminal pro‐B‐type natriuretic peptide were performed at hospital admission, hospital discharge, and recheck examinations. Lung ultrasound findings were compared between timepoints and to other clinical measures of L‐CHF.

Results

From time of hospital admission to discharge (mean 19.6 hours), median number of LUS sites strongly positive for B‐lines (>3 B‐lines per site) decreased from 5 (range, 1‐8) to 1 (range, 0‐5; P < .001), and median total B‐line score decreased from 37 (range, 6‐74) to 5 (range, 0‐32; P = .002). Lung ultrasound indices remained improved at first recheck (P < .001). Number of strong positive sites correlated positively with respiratory rate (r = 0.52, P = .008) and TXR edema score (r = 0.51, P = .009) at hospital admission. Patterns of edema resolution differed between LUS and TXR, with cranial quadrants showing more significant reduction in B‐lines compared to TXR edema score (80% vs 29% reduction, respectively; P = .003).

Conclusions and Clinical Importance

Lung ultrasound could be a useful tool for monitoring resolution of pulmonary edema in dogs with L‐CHF.

Ultrasound imaging of congestion in heart failure: examinations beyond the heart

Congestion, related to pressure and/or fluid overload, plays a central role in the pathophysiology, presentation and prognosis of heart failure and is an important therapeutic target. While symptoms and physical signs of fluid overload are required to make a clinical diagnosis of heart failure, they lack both sensitivity and specificity, which might lead to diagnostic delay and uncertainty. Over the last decades, new ultrasound methods for the detection of elevated intracardiac pressures and/or fluid overload have been developed that are more sensitive and specific, thereby enabling earlier and more accurate diagnosis and facilitating treatment strategies. Accordingly, we considered that a state-of-the-art review of ultrasound methods for the detection and quantification of congestion was timely, including imaging of the heart, lungs (B-lines), kidneys (intrarenal venous flow), and venous system (inferior vena cava and internal jugular vein diameter).

Congestion occurrence and evaluation in acute heart failure scenario: time to reconsider different pathways of volume overload

Although congestion is considered to be the main reason for hospital admission in patients with acute heart failure, a simplistic view considering idro saline retention and total body volume accumulation did not provide convincing data. Clinical congestion occurrence is often the tip of the iceberg of several different mechanisms ranging from increased filling pressure to extravascular fluid accumulation and blood flow redistribution. Therefore, the clinical evaluation is often restricted to a simple physical examination including few and inaccurate signs and symptoms. This superficial approach has led to contradictory data and patients have not been evaluated according to a more realistic clinical scenario. The integration with new diagnostic ultrasonographic and laboratory tools would substantially improve these weaknesses. Indeed, congestion could be assessed by following the most recognized HF subtypes including primitive cardiac defect, presence of right ventricular dysfunction, and organ perfusion. Moreover, there is a tremendous gap regarding the interchangeable concept of fluid retention and redistribution used with a univocal meaning. Overall, congestion assessment should be revised, considering it as either central, peripheral, or both. In this review, we aim to provide different evidence regarding the concept of congestion starting from the most recognized pathophysiological mechanisms of AHF decompensation. We highlight the fact that a better knowledge of congestion is a challenge for future investigation and it could lead to significant advances in HF treatment.

The haemodynamic basis of lung congestion during exercise in heart failure with preserved ejection fraction

AIMS

Increases in extravascular lung water (EVLW) during exercise contribute to symptoms, morbidity, and mortality in patients with heart failure and preserved ejection fraction (HFpEF), but the mechanisms leading to pulmonary congestion during exercise are not well-understood.

METHODS AND RESULTS

Compensated, ambulatory patients with HFpEF (n = 61) underwent invasive haemodynamic exercise testing using high-fidelity micromanometers with simultaneous lung ultrasound, echocardiography, and expired gas analysis at rest and during submaximal exercise. The presence or absence of EVLW was determined by lung ultrasound to evaluate for sonographic B-line artefacts. An increase in EVLW during exercise was observed in 33 patients (HFpEFLW+, 54%), while 28 (46%) did not develop EVLW (HFpEFLW-). Resting left ventricular function was similar in the groups, but right ventricular (RV) dysfunction was two-fold more common in HFpEFLW+ (64 vs. 31%), with lower RV systolic velocity and RV fractional area change. As compared to HFpEFLW-, the HFpEFLW+ group displayed higher pulmonary capillary wedge pressure (PCWP), higher pulmonary artery (PA) pressures, worse RV-PA coupling, and higher right atrial (RA) pressures during exercise, with increased haemoconcentration indicating greater loss of water from the vascular space. The development of lung congestion during exercise was significantly associated with elevations in PCWP and RA pressure as well as impairments in RV-PA coupling (area under the curve values 0.76-0.84).

CONCLUSION

Over half of stable outpatients with HFpEF develop increases in interstitial lung water, even during submaximal exercise. The acute development of lung congestion is correlated with increases in pulmonary capillary hydrostatic pressure that favours fluid filtration, and systemic venous hypertension due to altered RV-PA coupling, which may interfere with fluid clearance.

CLINICAL TRIAL REGISTRATION

NCT02885636.

Lung ultrasound: The future ahead and the lessons learned from COVID-19

Lung ultrasound (LUS) is a rapidly evolving field of application for ultrasound technologies. Especially during the current pandemic, many clinicians around the world have employed LUS to assess the condition of the lung for patients suspected and/or affected by COVID-19. However, LUS is currently performed with standard ultrasound imaging, which is not designed to cope with the high air content present in lung tissues. Nowadays LUS lacks standardization and suffers from the absence of quantitative approaches. To elevate LUS to the level of other ultrasound imaging applications, several aspects deserve attention from the technical and clinical world. This overview piece tries to provide the reader with a forward-looking view on the future for LUS.

Physiopathology and Diagnosis of Congestive Heart Failure: Consolidated Certainties and New Perspectives

Volume overload and fluid congestion are a fundamental issue in the assessment and management of patients with heart failure (HF). Recent studies have found that in acute decompensated heart failure (ADHF), right and left-sided pressures generally start to increase before any notable weight changes take place preceding an admission. ADHF may be a problem of volume redistribution among different vascular compartments instead of, or in addition to, fluid shift from the interstitial compartment. Thus, identifying heterogeneity of volume overload would allow guidance of tailored therapy. A comprehensive evaluation of congestive HF needs to take into account myriad parameters, including physical examination, echocardiographic values, and biomarker serum changes. Furthermore, potentially useful diagnostic tools include bioimpedance to measure intercompartmental fluid shifts, and evaluation of ultrasound lung comets to detect extravascular lung water.

Lung Ultrasound Eight-Point Method in Diagnosing Acute Heart Failure in Emergency Patients with Acute Dyspnea: Diagnostic Accuracy and 72 h Monitoring

Background and Objectives: Acute dyspnea is a common chief complaint in the emergency department (ED), with acute heart failure (AHF) as a frequent underlying disease. Early diagnosis and rapid therapy are highly recommended by international guidelines. This study evaluates the accuracy of point-of-care B-line lung ultrasound in diagnosing AHF and monitoring the therapeutic success of heart failure patients. Materials and Methods: This is a prospective mono-center study in adult patients presenting with undifferentiated acute dyspnea to a German ED. An eight-zone pulmonary ultrasound was performed by experienced sonographers in the ED and 24 and 72 h after. Along with the lung ultrasound evaluation patients were asked to assess the severity of shortness of breath on a numeric rating scale. The treating ED physicians were asked to assess the probability of AHF as the underlying cause. Final diagnosis was adjudicated by two independent experts. Follow-up was done after 30 and 180 days. Results: In total, 102 patients were enrolled. Of them, 89 patients received lung ultrasound evaluation in the ED. The sensitivity of lung ultrasound evaluation in ED in diagnosing AHF was 54.2%, specificity 97.6%. As much as 96.3% of patients with a positive LUS test result for AHF in ED actually suffered from AHF. Excluding diuretically pretreated patients, sensitivity of LUS increased to 75% in ED. Differences in the sum of B-lines between admission time point, 24 and 72 h were not statistically significant. There were no statistically significant differences in the subjectively assessed severity of dyspnea between AHF patients and those with other causes of dyspnea. Of the 89 patients, 48 patients received the final adjudicated diagnosis of AHF. ED physicians assessed the probability of AHF in patients with a final diagnosis of AHF as 70%. Roughly a quarter (23.9%) of the overall cohort patients were rehospitalized within 30 days after admission, 38.6% within 180 days of follow-up. Conclusion: In conclusion, point-of-care lung ultrasound is a helpful tool for the early rule-in of acute heart failure in ED but only partially suitable for exclusion. Of note, the present study shows no significant changes in the number of B-lines after 24 and 72 h.

Assessment of Hydration Status in Peritoneal Dialysis Patients: Validity, Prognostic Value, Strengths, and Limitations of Available Techniques

BACKGROUND

The majority of patients undergoing peritoneal dialysis (PD) suffer from volume overload and this overhydration is associated with increased mortality. Thus, optimal assessment of volume status in PD is an issue of paramount importance. Patient symptoms and physical signs are often unreliable indexes of true hydration status.

SUMMARY

Over the past decades, a quest for a valid, reproducible, and easily applicable technique to assess hydration status is taking place. Among existing techniques, inferior vena cava diameter measurements with echocardiography and natriuretic peptides such as brain natriuretic peptide and N-terminal pro-B-type natriuretic peptide were not extensively examined in PD populations; while having certain advantages, their interpretation are complicated by the underlying cardiac status and are not widely available. Bioelectrical impedance analysis (BIA) techniques are the most studied tool assessing volume overload in PD. Volume overload assessed with BIA has been associated with technique failure and increased mortality in observational studies, but the results of randomized trials on the value of BIA-based strategies to improve volume-related outcomes are contradictory. Lung ultrasound (US) is a recent technique with the ability to identify volume excess in the critical lung area. Preliminary evidence in PD showed that B-lines from lung US correlate with echocardiographic parameters but not with BIA measurements. This review presents the methods currently used to assess fluid status in PD patients and discusses existing data on their validity, applicability, limitations, and associations with intermediate and hard outcomes in this population. Key Message: No method has proved its value as an intervening tool affecting cardiovascular events, technique, and overall survival in PD patients. As BIA and lung US estimate fluid overload in different compartments of the body, they can be complementary tools for volume status assessment.

What are the minimum requirements to establish proficiency in lung ultrasound training for quantifying B-lines?

AIMS

The goal of this study was to determine the number of scans needed for novice learners to attain proficiency in B-line quantification compared with expert interpretation.

METHODS AND RESULTS

This was a prospective, multicentre observational study of novice learners, physicians and non-physicians from three academic institutions. Learners received a 2 h lung ultrasound (LUS) training session on B-line assessment, including lecture, video review to practice counting and hands-on patient scanning. Learners quantified B-lines using an eight-zone scanning protocol in patients with suspected acute heart failure. Ultrasound (US) machine settings were standardized to a depth of 18 cm and clip length of 6 s, and tissue harmonics and multibeam former were deactivated. For quantification, the intercostal space with the greatest number of B-lines within each zone was used for scoring. Each zone was given a score of 0-20 based on the maximum number of B-lines counted during one respiratory cycle. The B-line score was determined by multiplying the percentage of the intercostal space filled with B-lines by 20. We compared learner B-line counts with a blinded expert reviewer (five US fellowship-trained faculty with > 5 years of clinical experience) for each lung zone scanned; proficiency was defined as an intraclass correlation of > 0.7. Learning curves for each learner were constructed using cumulative sum method for statistical analysis. The Wilcoxon rank-sum test was used to compare the number of scans required to reach proficiency between different learner types. Twenty-nine learners (21 research associates, 5 residents and 3 non-US-trained emergency medicine faculty) scanned 2629 lung zones with acute pulmonary oedema. After a mean of 10.8 (standard deviation 14.0) LUS zones scanned, learners reached the predefined proficiency standard. The number of scanned zones required to reach proficiency was not significantly different between physicians and non-physicians (P = 0.26), learners with no prior US experience vs. > 25 prior patient scans (P = 0.64) and no prior vs. some prior LUS experience (P = 0.59). The overall intraclass correlation for agreement between learners and experts was 0.74 and 0.80 between experts.

CONCLUSIONS

Our results show that after a short, structured training, novice learners are able to achieve proficiency for quantifying B-lines on LUS after scanning 11 zones. These findings support the use of LUS for B-line quantification by non-physicians in clinical and research applications.

Essential Image Acquisition Protocols for Thoracic Ultrasonography

Image acquisition is the technique of correct placement, holding, and manipulation of the ultrasound probe in an ultrasound examination for the purpose of answering a specific clinical question. We review the literature and discuss the image acquisition protocols used for thoracic ultrasound, explaining, where possible, the associated advantages, disadvantages, and alternatives. A better understanding of how to fine-tune image acquisition specifically for thoracic ultrasound will help physicians on all levels to standardise their practice and improve networking and collaboration. It will also lead to better-quality investigations and, potentially, new applications.

[Lung Ultrasound: new Opportunities for a Cardiologist]

This review focused on ultrasound examination of lungs, a useful complement to transthoracic echocardiography (EchoCG), which is superior to chest X-ray in the diagnostic value. The lung acoustic window always remains open and allows obtaining high-quality images in most cases. For a cardiologist, the major points of the method application are determination of pleural effusion and lung congestion. This method has a number of advantages: it is time-saving; cost-effective; portable and accessible; can be used in a real-time mode; not associated with radiation; reproducible; and highly informative. The ultrasound finding of wet lungs would indicate threatening, acute cardiac decompensation long before appearance of clinical, auscultative, and radiological signs of lung congestion. Modern EchoCG should include examination of the heart and lungs as a part of a single, integrative ultrasound examination.

The Cardiorenal Syndrome in Heart Failure

Abnormal fluid handling leads to physiologic abnormalities in multiple organ systems. Deranged hemodynamics, neurohormonal activation, excessive tubular sodium reabsorption, inflammation, oxidative stress, and nephrotoxic medications are important drivers of harmful cardiorenal interactions in patients with heart failure. Accurate quantitative measurement of fluid volume is vital to individualizing therapy for such patients. Blood volume analysis and pulmonary artery pressure monitoring seem the most reliable methods for assessing fluid volume and guiding decongestive therapies. Still the cornerstone of decongestive therapy, diuretics' effectiveness decreases with progression of heart failure. Extracorporeal ultrafiltration, an alternative to diuretics, has been shown to reduce heart-failure events.

Lung Ultrasound Imaging, a Technical Review

Lung ultrasound (LUS) is a growing and fascinating field of application for ultrasound imaging. Despite the difficulties in imaging an organ largely filled with air, the potential benefits originating from an effective ultrasound method focusing on monitoring and diagnosing lung diseases represent a tremendous stimulus for research in this direction. This paper presents a technical review where, after a brief historical overview, the current limitations of LUS imaging are discussed together with a description of the physical phenomena at stake. Next, the paper focuses on the latest technical developments of LUS.

Lung Ultrasound for the Cardiologist

For a cardiologist, lung ultrasound is an add-on to transthoracic echocardiography, just as lung auscultation is part of a cardiac physical examination. A cardiac 3.5- to 5.0-MHz transducer is generally suitable because the small footprint makes it ideal for scanning intercostal spaces. The image quality is often adequate, and the lung acoustic window is always patent. The cumulative increase in imaging time is <1 min for the 2 main applications targeted on pleural water (pleural effusion) and lung water (pulmonary congestion as multiple B-lines). In these settings, lung ultrasound outperforms the diagnostic accuracy of the chest radiograph, with a low-cost, portable, real-time, radiation-free method. A "wet lung" detected by lung ultrasound predicts impending acute heart failure decompensation and may trigger lung decongestion therapy. The doctors of tomorrow may still listen with a stethoscope to their patient's lung, but they will certainly be seeing it with ultrasound.

Lung ultrasound in infants with bronchiolitis

Lung ultrasound (LUS) is nowadays a fast-growing field of study since the technique has been widely acknowledged as a cost-effective, radiation free, and ready available alternative to standard X-ray imaging. However, despite extensive acoustic characterization studies and documented medical evidences, a lot is still unknown about how ultrasounds interact with lung tissue. One of the most discussed lung artifacts are the B-lines [in all ages] and the subpleural consolidations (in young infants). Recently, LUS has been claimed to be able to detect pneumonia in infants with bronchiolitis, although this can be an overestimation due to the peculiar physiology of small peripheral airways of the pediatric lung (particularly in neonate/infants). Distinguishing consolidations from atelectasis in young infants with bronchiolitis can be challenging and those criteria well defined for adults and older children (size and bronchogram) cannot easily translated in this specific subset. Therefore, if decades of studies clearly defined the low risk of SBI in bronchiolitis, we need to be careful before stating that LUS may confirm pneumonia in such a high number of cases and, importantly, new and promising techniques such as LUS should give us new insights bringing us to improvements and not back to overuse of antibiotics. More studies are surely need on this topic.

Effect of a Therapeutic Strategy Guided by Lung Ultrasound on 6-Month Outcomes in Patients with Heart Failure: Randomized, Multicenter Trial (EPICC Study)

INTRODUCTION AND OBJECTIVES

Pulmonary congestion (PC) is associated with an increased risk of hospitalization and death in patients with heart failure (HF). Lung ultrasound has shown to be highly sensitive for detecting PC in HF. The aim of this study is to evaluate whether lung ultrasound-guided therapy improves 6-month outcomes in patients with HF compared with conventional treatment.

MATERIALS AND METHODS

Randomized, multicenter, single-blind clinical trial in patients discharged from Internal Medicine Departments after hospitalization for decompensated HF. Participants will be assigned 1:1 to receive treatment guided according to the presence of lung ultrasound signs of congestion (semi-quantitative evaluation of B lines and the presence of pleural effusion) versus clinical assessment of congestion. The primary outcome is the combination of cardiovascular death and readmission for HF at 6 months.

CONCLUSIONS

The results of this study will provide more evidence about the impact of lung ultrasound on treatment monitoring in patients with chronic HF.