Ultrasound patterns of pulmonary edema

Applications of lung ultrasound as an emerging tool in neonates

Lung ultrasound is increasingly used in neonatal intensive care units. We summarized the ultrasonographic patterns, features of most neonatal respiratory morbidities, and clinical application in neonates. Lung ultrasound is a non-invasive, radiation-free, and reproducible adjunct tool that can guide the clinical management of neonates presenting with respiratory distress.

The Rat Thoracic Ultrasound protocol: scanning technique and normal findings

Respiratory diseases (especially pneumonia) are very common disorders in pet rats. The suspected diagnosis is mostly based on the clinical signs, thoracic auscultation, and thoracic radiography. However, auscultation is insensitive in determining the severity of the disease, and radiographs are often unremarkable. Non-cardiac thoracic ultrasonography is increasingly used in veterinary medicine; however, it has not been described in detail in rats. Thoracic ultrasonic examination was conducted on 400 client-owned conscious pet rats. The rats were examined in the period from June 2023 to August 2023 in two veterinary clinics. Due to the small size of the animal, different anatomical considerations, and different evaluation protocols, as well as to meet the optimal outcome of detailed thoracic ultrasound, a standard methodological protocol was developed, and the name RATTUS (Rat Thoracic Ultrasound) was proposed. Typical signs of normal RATTUS were described (bat sign, lung sliding, A-lines, abdominal curtain sign, ski jump sign, lung pulse, seashore sign in M-mode, and bamboo sign). The new evaluation of lung inflation symmetry by substernal access was also described. The methodical approach presented and the normal findings description are proposed to be used for a standard/routine thoracic ultrasound examination in pet rats.

Clinical Review of Hypertensive Acute Heart Failure

Although acute heart failure (AHF) is a common disease associated with significant symptoms, morbidity and mortality, the diagnosis, risk stratification and treatment of patients with hypertensive acute heart failure (H-AHF) still remain a challenge in modern medicine. Despite great progress in diagnostic and therapeutic modalities, this disease is still accompanied by a high rate of both in-hospital (from 3.8% to 11%) and one-year (from 20% to 36%) mortality. Considering the high rate of rehospitalization (22% to 30% in the first three months), the treatment of this disease represents a major financial blow to the health system of each country. This disease is characterized by heterogeneity in precipitating factors, clinical presentation, therapeutic modalities and prognosis. Since heart decompensation usually occurs quickly (within a few hours) in patients with H-AHF, establishing a rapid diagnosis is of vital importance. In addition to establishing the diagnosis of heart failure itself, it is necessary to see the underlying cause that led to it, especially if it is de novo heart failure. Given that hypertension is a precipitating factor of AHF and in up to 11% of AHF patients, strict control of arterial blood pressure is necessary until target values are reached in order to prevent the occurrence of H-AHF, which is still accompanied by a high rate of both early and long-term mortality.

Thoracic Ultrasound in COVID-19: Use of Lung and Diaphragm Ultrasound in Evaluating Dyspnea in Survivors of Acute Respiratory Distress Syndrome from COVID-19 Pneumonia in a Post-ICU Clinic

INTRODUCTION

Dyspnea is a common symptom in survivors of severe COVID-19 pneumonia. While frequently employed in hospital settings, the use of point-of-care ultrasound in ambulatory clinics for dyspnea evaluation has rarely been explored. We aimed to determine how lung ultrasound score (LUS) and inspiratory diaphragm excursion (DE) correlate with patient-reported dyspnea during a 6-min walk test (6MWT) in survivors of COVID-19 acute respiratory distress syndrome (ARDS). We hypothesize higher LUS and lower DE will correlate with dyspnea severity.

STUDY DESIGN AND METHODS

Single-center cross-sectional study of survivors of critically ill COVID-19 pneumonia (requiring high-flow nasal cannula, invasive, or non-invasive mechanical ventilation) seen in our Post-ICU clinic. All patients underwent standardized scanning protocols to compute LUS and DE. Pearson correlations were performed to detect an association between LUS and DE with dyspnea at rest and exertion during 6MWT.

RESULTS

We enrolled 45 patients. Average age was 61.5 years (57.7% male), with average BMI of 32.3 Higher LUS correlated significantly with dyspnea, at rest (r =  + 0.41, p =  < 0.01) and at exertion (r =  + 0.40, p =  < 0.01). Higher LUS correlated significantly with lower oxygen saturation during 6MWT (r = -0.55, p =  < 0.01) and lower 6MWT distance (r = -0.44, p =  < 0.01). DE correlated significantly with 6MWT distance but did not correlate with dyspnea at rest or exertion.

CONCLUSION

Higher LUS correlated significantly with patient-reported dyspnea at rest and exertion. Higher LUS significantly correlated with more exertional oxygen desaturation during 6MWT and lower 6MWT distance. DE did not correlate with dyspnea.

New International Guidelines and Consensus on the Use of Lung Ultrasound

Following the innovations and new discoveries of the last 10 years in the field of lung ultrasound (LUS), a multidisciplinary panel of international LUS experts from six countries and from different fields (clinical and technical) reviewed and updated the original international consensus for point-of-care LUS, dated 2012. As a result, a total of 20 statements have been produced. Each statement is complemented by guidelines and future developments proposals. The statements are furthermore classified based on their nature as technical (5), clinical (11), educational (3), and safety (1) statements.

Vertical Artifacts as Lung Ultrasound Signs: Trick or Trap? Part 2- An Accademia di Ecografia Toracica Position Paper on B-Lines and Sonographic Interstitial Syndrome

Although during the last few years the lung ultrasound (LUS) technique has progressed substantially, several artifacts, which are currently observed in clinical practice, still need a solid explanation of the physical phenomena involved in their origin. This is particularly true for vertical artifacts, conventionally known as B-lines, and for their use in clinical practice. A wider consensus and a deeper understanding of the nature of these artifactual phenomena will lead to a better classification and a shared nomenclature, and, ultimately, result in a more objective correlation between anatomo-pathological data and clinical scenarios. The objective of this review is to collect and document the different signs and artifacts described in the history of chest ultrasound, with a particular focus on vertical artifacts (B-lines) and sonographic interstitial syndrome (SIS). By reviewing the possible physical and anatomical interpretation of the signs and artifacts proposed in the literature, this work also aims to bring order to the available studies and to present the AdET (Accademia di Ecografia Toracica) viewpoint in terms of nomenclature and clinical approach to the SIS.

Endotypes of Prematurity and Phenotypes of Bronchopulmonary Dysplasia: Toward Personalized Neonatology

Bronchopulmonary dysplasia (BPD), the chronic lung disease of prematurity, is increasingly recognized as the consequence of a pathological reparative response of the developing lung to both antenatal and postnatal injury. According to this view, the pathogenesis of BPD is multifactorial and heterogeneous with different patterns of antenatal stress (endotypes) that combine with varying postnatal insults and might distinctively damage the development of airways, lung parenchyma, interstitium, lymphatic system, and pulmonary vasculature. This results in different clinical phenotypes of BPD. There is no clear consensus on which are the endotypes of prematurity but the combination of clinical information with placental and bacteriological data enables the identification of two main pathways leading to birth before 32 weeks of gestation: (1) infection/inflammation and (2) dysfunctional placentation. Regarding BPD phenotypes, the following have been proposed: parenchymal, peripheral airway, central airway, interstitial, congestive, vascular, and mixed phenotype. In line with the approach of personalized medicine, endotyping prematurity and phenotyping BPD will facilitate the design of more targeted therapeutic and prognostic approaches.

What Is COVID 19 Teaching Us about Pulmonary Ultrasound?

In lung ultrasound (LUS), the interactions between the acoustic pulse and the lung surface (including the pleura and a small subpleural layer of tissue) are crucial. Variations of the peripheral lung density and the subpleural alveolar shape and its configuration are typically connected to the presence of ultrasound artifacts and consolidations. COVID-19 pneumonia can give rise to a variety of pathological pulmonary changes ranging from mild diffuse alveolar damage (DAD) to severe acute respiratory distress syndrome (ARDS), characterized by peripheral bilateral patchy lung involvement. These findings are well described in CT imaging and in anatomopathological cases. Ultrasound artifacts and consolidations are therefore expected signs in COVID-19 pneumonia because edema, DAD, lung hemorrhage, interstitial thickening, hyaline membranes, and infiltrative lung diseases when they arise in a subpleural position, generate ultrasound findings. This review analyzes the structure of the ultrasound images in the normal and pathological lung given our current knowledge, and the role of LUS in the diagnosis and monitoring of patients with COVID-19 lung involvement.

Lung ultrasound to detect cardiopulmonary interactions in acutely ill children

OBJECTIVE AND DESIGN

Our prospective observational study is the first study that evaluates the lung ultrasound (LUS) findings of cardiopulmonary interactions in acutely ill children with elevated pro-brain natriuretic peptide (BNP) levels, with the aim of establishing the specific LUS pattern in this category of patients without primary lung diseases.

METHODOLOGY

We prospectively analyzed epidemiological, clinical, laboratory, instrumental, and lung ultrasound parameters in acutely ill children aged 1 month to 18 years admitted to the Department of Pediatrics between March 2020 to August 2020. Among the acutely ill patients evaluated, only patients with pro-BNP > 300 pg/ml and who underwent LUS before the start of any treatment were included. They were stratified into three subcategories based on the diagnosis (A) cardiac disease, (B) systemic inflammatory disease/sepsis without functional and/or organic alterations of the myocardium, and (C) systemic inflammatory disease/sepsis and cardiac disease, and were classified into two groups based on the level of pro-BNP. We also enrolled patients belonging to two other categories (patients with primary infectious lung disease and completely healthy patients) analyzing their epidemiological, clinical, laboratory, instrumental parameters, and lung ultrasound findings and comparing them with those of acutely ill children.

RESULTS AND CONCLUSION

We found that LUS findings in these acutely ill children are different from the ultrasound pattern of other categories of children and in particular (1) children with acute lower respiratory tract infections and (2) healthy infants. The finding in a child of a sonographic interstitial syndrome with multiple, bright, long, separate, and nonconfluent B-lines/long vertical artifacts deriving from a normal and regular pleural line, in the absence of subpleural consolidations, is strongly predictive of cardiogenic pulmonary edema or pulmonary congestion in the course of systemic inflammatory disease/sepsis.

Implementation of lung ultrasound in low- to middle-income countries: a new challenge global health?

Pneumonia remains the leading cause of death globally in children under the age of five. The poorest children are the ones most at risk of dying. In the recent years, lung ultrasound has been widely documented as a safe and easy tool for the diagnosis and monitoring of pneumonia and several other respiratory infections and diseases. During the pandemic, it played a primary role to achieve early suspicion and prediction of severe COVID-19, reducing the risk of exposure of healthcare workers to positive patients. However, innovations that can improve diagnosis and treatment allocation, saving hundreds of thousands of lives each year, are not reaching those who need them most. In this paper, we discuss advantages and limits of different tools for the diagnosis of pneumonia in low- to middle-income countries, highlighting potential benefits of a wider access to lung ultrasound in these settings and barriers to its implementation, calling international organizations to ensure the indiscriminate access, quality, and sustainability of the provision of ultrasound services in every setting. What is Known: • Pneumonia remains the leading cause of death globally in children under the age of five. The poorest children are the ones most at risk of dying. In the recent years, lung ultrasound has been widely documented as a safe and easy tool for the diagnosis and monitoring of pneumonia and several other respiratory infections and diseases. During the pandemic, it played a primary role to achieve early suspicion and prediction of severe COVID-19, reducing the risk of exposure of healthcare workers to positive patients. However, innovations that can improve diagnosis and treatment allocation, saving hundreds of thousands of lives each year, are not reaching those who need them most. What is New: • We discuss advantages and limits of different tools for the diagnosis of pneumonia in low- to middle-income countries, highlighting potential benefits of a wider access to lung ultrasound in these settings and barriers to its implementation, calling international organizations to ensure the indiscriminate access, quality, and sustainability of the provision of ultrasound services in every setting.

Lung ultrasound in a tertiary intensive care unit population: a diagnostic accuracy study

BACKGROUND

Evidence from previous studies comparing lung ultrasound to thoracic computed tomography (CT) in intensive care unit (ICU) patients is limited due to multiple methodologic weaknesses. While addressing methodologic weaknesses of previous studies, the primary aim of this study is to investigate the diagnostic accuracy of lung ultrasound in a tertiary ICU population.

METHODS

This is a single-center, prospective diagnostic accuracy study conducted at a tertiary ICU in the Netherlands. Critically ill patients undergoing thoracic CT for any clinical indication were included. Patients were excluded if time between the index and reference test was over eight hours. Index test and reference test consisted of 6-zone lung ultrasound and thoracic CT, respectively. Hemithoraces were classified by the index and reference test as follows: consolidation, interstitial syndrome, pneumothorax and pleural effusion. Sensitivity, specificity, positive and negative likelihood ratio were estimated.

RESULTS

In total, 87 patients were included of which eight exceeded the time limit and were subsequently excluded. In total, there were 147 respiratory conditions in 79 patients. The estimated sensitivity and specificity to detect consolidation were 0.76 (95%CI: 0.68 to 0.82) and 0.92 (0.87 to 0.96), respectively. For interstitial syndrome they were 0.60 (95%CI: 0.48 to 0.71) and 0.69 (95%CI: 0.58 to 0.79). For pneumothorax they were 0.59 (95%CI: 0.33 to 0.82) and 0.97 (95%CI: 0.93 to 0.99). For pleural effusion they were 0.85 (95%CI: 0.77 to 0.91) and 0.77 (95%CI: 0.62 to 0.88).

CONCLUSIONS

In conclusion, lung ultrasound is an adequate diagnostic modality in a tertiary ICU population to detect consolidations, interstitial syndrome, pneumothorax and pleural effusion. Moreover, one should be careful not to interpret lung ultrasound results in deterministic fashion as multiple respiratory conditions can be present in one patient. Trial registration This study was retrospectively registered at Netherlands Trial Register on March 17, 2021, with registration number NL9344.

Association Between Arterial Oxygen Saturation and Lung Ultrasound B-Lines After Competitive Deep Breath-Hold Diving

Breath-hold diving (freediving) is an underwater sport that is associated with elevated hydrostatic pressure, which has a compressive effect on the lungs that can lead to the development of pulmonary edema. Pulmonary edema reduces oxygen uptake and thereby the recovery from the hypoxia developed during freediving, and increases the risk of hypoxic syncope. We aimed to examine the efficacy of SpO₂, via pulse-oximetry, as a tool to detect pulmonary edema by comparing it to lung ultrasound B-line measurements after deep diving. SpO₂ and B-lines were collected in 40 freedivers participating in an international deep freediving competition. SpO₂ was measured within 17 ± 6 min and lung B-lines using ultrasound within 44 ± 15 min after surfacing. A specific symptoms questionnaire was used during SpO₂ measurements. We found a negative correlation between B-line score and minimum SpO₂ (r_s = −0.491; p = 0.002) and mean SpO₂ (r_s = −0.335; p = 0.046). B-line scores were positively correlated with depth (r_s = 0.408; p = 0.013), confirming that extra-vascular lung water is increased with deeper dives. Compared to dives that were asymptomatic, symptomatic dives had a 27% greater B-line score, and both a lower mean and minimum SpO₂ (all p < 0.05). Indeed, a minimum SpO₂ ≤ 95% after a deep dive has a positive predictive value of 29% and a negative predictive value of 100% regarding symptoms. We concluded that elevated B-line scores are associated with reduced SpO₂ after dives, suggesting that SpO₂ via pulse oximetry could be a useful screening tool to detect increased extra-vascular lung water. The practical application is not to diagnose pulmonary edema based on SpO₂ – as pulse oximetry is inexact – rather, to utilize it as a tool to determine which divers require further evaluation before returning to deep freediving.

Clinical applications of Lung Ultrasound in children in Pediatric Emergency Setting: a lesson from a child with severe heart disease

Background and aim:

Rheumatic Heart Disease (RHD) often evolves in congestive heart failure with development of pulmonary edema after a asymptomatic, latent phase. In the last years, Lung Ultrasound (LUS) has gained a primary role in the diagnosis and management of pleuropulmonary disorders, also in pediatric practice, and in the diagnosis and follow-up of pulmonary edema through qualitative analysis of ultrasound B-lines. Aim of this case report is to keep high clinicians’ attention to the diagnosis of Rheumatic Heart Disease also in high-income countries and to deepen the role and importance of lung ultrasound in clinical practice, in diagnosis and follow-up of pediatric lung diseases, especially in emergency settings as happened in our case.

Methods:

We present the case of a 14-year-old Italian boy from a medium-low socio-economic and cultural class Italian family, who was diagnosed with severe and advanced stage RHD, which had remained undiagnosed until then.

Results and Conclusions:

In the diagnostic process of our case, LUS played a fundamental role because it quickly directed us, contextually to the clinical and anamnestic evaluation, towards the right diagnosis, in a Pediatric Emergency Department. In clinical practice, the only LUS findings and the only qualitative analysis of the B-lines, have note made clinicians able to make a clear characterization yet. Thus, the study of cardiovascular function, laboratory parameters, anamnestic and clinical data continue to be useful tools in order to assist LUS in the diagnostic processes of lung diseases, as in our case. (www.actabiomedica.it)

Assessment of Volume Status and Fluid Responsiveness in Small Animals

Intravenous fluids are an essential component of shock management in human and veterinary emergency and critical care to increase cardiac output and improve tissue perfusion. Unfortunately, there are very few evidence-based guidelines to help direct fluid therapy in the clinical setting. Giving insufficient fluids and/or administering fluids too slowly to hypotensive patients with hypovolemia can contribute to continued hypoperfusion and increased morbidity and mortality. Similarly, giving excessive fluids to a volume unresponsive patient can contribute to volume overload and can equally increase morbidity and mortality. Therefore, assessing a patient's volume status and fluid responsiveness, and monitoring patient's response to fluid administration is critical in maintaining the balance between meeting a patient's fluid needs vs. contributing to complications of volume overload. This article will focus on the physiology behind fluid responsiveness and the methodologies used to estimate volume status and fluid responsiveness in the clinical setting.

Clinical Impact of Vertical Artifacts Changing with Frequency in Lung Ultrasound

Background: This study concerns the application of lung ultrasound (LUS) for the evaluation of the significance of vertical artifact changes with frequency and pleural line abnormalities in differentiating pulmonary edema from pulmonary fibrosis. Study Design and Methods: The study was designed as a diagnostic test. Having qualified patients for the study, an ultrasound examination was performed, consistent with a predetermined protocol, and employing convex and linear transducers. We investigated the possibility of B-line artifact conversion depending on the set frequency (2 MHz and 6 MHz), and examined pleural line abnormalities. Results: The study group comprised 32 patients with interstitial lung disease (ILD) (and fibrosis) and 30 patients with pulmonary edema. In total, 1941 cineloops were obtained from both groups and analyzed. The employment of both types of transducers (linear and convex) was most effective (specificity 91%, specificity 97%, positive predictive value (PPV) 97%, negative predictive value (NPV) 91%, LR(+) 27,19, LR(−) 0.097, area under curve (AUC) = 0.936, p = 7 × 10⁻⁶). Interpretation: The best accuracy in differentiating the etiology of B-line artifacts was obtained with the use of both types of transducers (linear and convex), complemented with the observation of the conversion of B-line artifacts to Z-line.

A Case of Bedside Ultrasound in COVID-19 to Prognosticate Functional Lung Recovery

Introduction. The fight against COVID-19 poses questions as to the clinical presentation, course, diagnosis, and treatment of the condition. This case study presents a patient infected with COVID-19 and suggests with additional research, that bedside ultrasound may be used to diagnose severity of disease and potentially, prognosticate functional lung recovery without using unnecessary resources and exposing additional healthcare professionals to infection. Case Report. A 46-year-old male presented to the emergency department (ED) with cough, fever, and shortness of breath. Chest X-ray showed patchy airspace opacities bilaterally. Rapid testing resulted positive for SARS-CoV-2. Bedside ultrasound showed abnormal lung parenchyma, with diffuse comet tail artifacts, consistent with interstitial pulmonary edema. Following a prolonged intubation, patient's abnormal lung ultrasound findings are resolved.

Lung mass density prediction using machine learning based on ultrasound surface wave elastography and pulmonary function testing

OBJECTIVE

The objective of this study is to predict in vivo lung mass density for patients with interstitial lung disease using different gradient boosting decision tree (GBDT) algorithms based on measurements from lung ultrasound surface wave elastography (LUSWE) and pulmonary function testing (PFT).

METHODS

Age and weight of study subjects (57 patients with interstitial lung disease and 20 healthy subjects), surface wave speeds at three vibration frequencies (100, 150, and 200 Hz) from LUSWE, and predicted forced expiratory volume (FEV1% pre) and ratio of forced expiratory volume to forced vital capacity (FEV1%/FVC%) from PFT were used as inputs while lung mass densities based on the Hounsfield Unit from high resolution computed tomography (HRCT) were used as labels to train the regressor in three GBDT algorithms, XGBoost, CatBoost, and LightGBM. 80% (20%) of the dataset was used for training (testing).

RESULTS

The results showed that predictions using XGBoost regressor obtained an accuracy of 0.98 in the test dataset.

CONCLUSION

The obtained results suggest that XGBoost regressor based on the measurements from LUSWE and PFT may be able to noninvasively assess lung mass density in vivo for patients with pulmonary disease.

COVID 19 infection: Pediatric perspectives

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread across the globe, causing innumerable deaths and a massive economic catastrophe. Exposure to household members with confirmed COVID-19 is the most common source of infection among children. Children are just as likely as adults to get infected with SARS-CoV-2. Most children are asymptomatic and when symptoms occur, they are usually mild. Infants <12 months old are at a higher risk for severe or critical disease. COVID-19 is diagnosed the same way in pediatric population as adults by testing specimen obtained from upper respiratory tract for nucleic acid amplification test (NAAT) using reverse transcriptase viral polymerase chain reaction (RT-PCR). The common laboratory findings in hospitalized patient include leukopenia, lymphopenia, and increased levels of inflammatory markers. Chest X-ray findings are variable and computed tomography scans of the chest may show ground glass opacities similar to adults or non-specific findings. Prevention is the primary intervention strategy. Recently the U.S. Food and Drug Administration (FDA) has provided emergency authorization of the Pfizer-BioNTech COVID-19 vaccine and many other vaccine candidates are in the investigational stage. There is limited data in children on the use of antivirals, hydroxychloroquine, azithromycin, monoclonal antibody, and convalescent plasma. Oxygen therapy is required in hypoxic children (saturation <92%). Similar to adults, other measures to maintain oxygenation such as high flow nasal cannula, CPAP, or ventilatory support may be needed. Ventilatory management strategies should include use of low tidal volumes (5-6 cc/kg), high positive expiratory pressure, adequate sedation, paralysis, and prone positioning. Recently, a new entity associated with COVID-19 called multisystem inflammatory syndrome in children (MIS-C) has emerged. Clinical, laboratory, and epidemiological criteria are the basis for this diagnosis. Management options include ICU admission, steroids, intravenous gamma globulin, aspirin, anakinra, and anticoagulants. Vasoactive-inotropic score (VIS) is used to guide vasopressor support.

[Lung ultrasound in patients with SARS-CoV-2 infection]

After taking a patient's history and physical examination, lung ultrasound can immediately reveal numerous causes and complications in patients suffering from respiratory tract infection and/or dyspnea. It can thus facilitate decisions on further diagnostic and first therapeutic procedures, even in patients with a SARS-CoV‑2 infection who present to the emergency room. This review article highlights the typical findings of lung ultrasound in patients with COVID-19 and discusses its value compared to other imaging methods.

Lung ultrasound in the diagnosis of COVID-19 infection - A case series and review of the literature

COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and spreading worldwide has become a serious challenge for the entire health care system as regards infection prevention, rapid diagnosis, and treatment. Lung ultrasound (LUS) is a dynamically developing diagnostic method used in intensive care, cardiology and nephrology, it can also be helpful in diagnosing and monitoring pneumonia. Interstitial pneumonia appears to be the most common clinical manifestation of coronavirus infection. We present 4 case reports of COVID-19 involving the lungs, in which transthoracic lung ultrasound was successfully utilized as a constituent of bedside diagnostics and a review of the literature concerning potential use of LUS in COVID-19 diagnostics. The possibility to perform this examination repeatedly, its non-invasiveness and high sensitivity make it an important element of care provided for patients with viral pneumonia.

B-Lines for the assessment of extravascular lung water: Just focused or semi-quantitative?

BACKGROUND

B-lines as typical artefacts of lung ultrasound are considered as surrogate measurement for extravascular lung water. However, B-lines develop in the sub-pleural space and do not allow assessment of the whole lung. Here, we present data from the first observational multi-centre study focusing on the correlation between a B-lines score and extravascular lung water in critically ill patients suffering from a variety of diseases.

PATIENTS AND METHODS

In 184 adult patients, 443 measurements were obtained. B-lines were counted and expressed in a score which was compared to extravascular lung water, measured by single-indicator transpulmonary thermodilution. Appropriate correlation coefficients were calculated and receiver operating characteristics (ROC-) curves were plotted.

RESULTS

Overall, B-lines score was correlated with body weight-indexed extravascular lung water characterized by r = .59. The subgroup analysis revealed a correlation coefficient in patients without an infection of r = .44, in those with a pulmonary infection of r = .75 and in those with an abdominal infection of r = .23, respectively. Using ROC-analysis the sensitivity and specificity of B-lines for detecting an increased extravascular lung water (>10 mL/kg) was 63% and 79%, respectively. In patients with a P/F ratio <200 mm Hg, sensitivity and specificity to predict an increased extravascular lung water was 71% and 93%, respectively.

CONCLUSIONS

Assessment of B-lines does not accurately reflect actual extravascular lung water. In presence of an impaired oxygenation, B-lines may reliably indicate increased extravascular lung water as cause of the oxygenation disorders.

[Lung Ultrasound in Differential Diagnosis of Dyspnea]

Lung Ultrasound in Differential Diagnosis of Dyspnea Abstract. Lung ultrasound offers an immediate diagnosis in accordance with the clinical examination in many causes of dyspnea: pleural effusion, pulmonary edema, pneumonia, pulmonary embolism and interstitial lung diseases. At first level exam, CXR, despite its intrinsic limitations and low accuracy, may still play a relevant role. CT scan remains the gold standard, but it requires patient transportation and use of radiation, which precludes an extensive use especially within the same patient. Lung ultrasound, after proper training of the physician, is able to provide greater accuracy than CXR and similar accuracy to the CT scan.

Localizing B-Lines in Lung Ultrasonography by Weakly Supervised Deep Learning, In-Vivo Results

Lung ultrasound (LUS) is nowadays gaining growing attention from both the clinical and technical world. Of particular interest are several imaging-artifacts, e.g., A- and B- line artifacts. While A-lines are a visual pattern which essentially represent a healthy lung surface, B-line artifacts correlate with a wide range of pathological conditions affecting the lung parenchyma. In fact, the appearance of B-lines correlates to an increase in extravascular lung water, interstitial lung diseases, cardiogenic and non-cardiogenic lung edema, interstitial pneumonia and lung contusion. Detection and localization of B-lines in a LUS video are therefore tasks of great clinical interest, with accurate, objective and timely evaluation being critical. This is particularly true in environments such as the emergency units, where timely decision may be crucial. In this work, we present and describe a method aimed at supporting clinicians by automatically detecting and localizing B-lines in an ultrasound scan. To this end, we employ modern deep learning strategies and train a fully convolutional neural network to perform this task on B-mode images of dedicated ultrasound phantoms in-vitro, and on patients in-vivo. An accuracy, sensitivity, specificity, negative and positive predictive value equal to 0.917, 0.915, 0.918, 0.950 and 0.864 were achieved in-vitro, respectively. Using a clinical system in-vivo, these statistics were 0.892, 0.871, 0.930, 0.798 and 0.958, respectively. We moreover calculate neural attention maps that visualize which components in the image triggered the network, thereby offering simultaneous weakly-supervised localization. These promising results confirm the capability of the proposed method to identify and localize the presence of B-lines in clinical lung ultrasonography.