A growing amount of evidence prompts us to update the first version of recommendations for lung ultrasound in internal medicine (POLLUS-IM) that was published in 2018. The recommendations were established in several stages, consisting of: literature review, assessment of literature data quality (with the application of QUADAS, QUADAS-2 and GRADE criteria) and expert evaluation carried out consistently with the modified Delphi method (three rounds of on-line discussions, followed by a secret ballot by the panel of experts after each completed discussion). Publications to be analyzed were selected from the following databases: Pubmed, Medline, OVID, and Embase. New reports published as of October 2019 were added to the existing POLLUS-IM database used for the original publication of 2018. Altogether, 528 publications were systematically reviewed, including 253 new reports published between September 2017 and October 2019. The new recommendations concern the following conditions and issues: pneumonia, heart failure, monitoring dialyzed patients’ hydration status, assessment of pleural effusion, pulmonary embolism and diaphragm function assessment. POLLUS-IM 2020 recommendations were established primarily for clinicians who utilize lung ultrasound in their everyday clinical work.

Recommendations for Lung Ultrasound in Internal Medicine

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.

New International Guidelines and Consensus on the Use of Lung Ultrasound

Potential ultrasound exposure safety issues are reviewed, with guidance for prudent use of point-of-care ultrasound (POCUS). Safety assurance begins with the training of POCUS practitioners in the generation and interpretation of diagnostically valid and clinically relevant images. Sonographers themselves should minimize patient exposure in accordance with the as-low-as-reasonably-achievable principle, particularly for the safety of the eye, lung, and fetus. This practice entails the reduction of output indices or the exposure duration, consistent with the acquisition of diagnostically definitive images. Informed adoption of POCUS worldwide promises a reduction of ionizing radiation risks, enhanced cost-effectiveness, and prompt diagnoses for optimal patient care.

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Diagnostic Ultrasound Safety Review for Point-of-Care Ultrasound Practitioners.

The comet tail artefact is probably one of the most commonly and imprecisely used to describe vertical artefacts found in lung ultrasound. Two distinct artefacts are commonly observed: the lung comets and the B-lines. Both artefacts differ with regard to generation mechanism and clinical significance. This review explores the current understanding and use of these two artefacts in lung ultrasound and suggests how to avoid the pitfalls related to confusing comet tail artefacts with other vertical artefacts.

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A Common Misunderstanding in Lung Ultrasound: The Comet Tail Artefact

The induction of pulmonary capillary hemorrhage (PCH) is a well-established non-thermal biological effect of pulsed ultrasound in animal models. Typically, research has been done using laboratory pulsed ultrasound systems with a fixed beam and, recently, by B-mode diagnostic ultrasound. In this study, a GE Vivid 7 Dimension ultrasound machine with 10 L linear array probe was used at 6.6 MHz to explore the relative PCH efficacy of B-mode imaging, M-mode (fixed beam), color angio mode Doppler imaging and pulsed Doppler mode (fixed beam). Anesthetized rats were scanned in a warmed water bath, and thresholds were determined by scanning at different power steps, 2 dB apart, in different groups of six rats. Exposures were performed for 5 min, except for a 15-s M-mode group. Peak rarefactional pressure amplitude thresholds were 1.5 MPa for B-mode and 1.1 MPa for angio Doppler mode. For the non-scanned modes, thresholds were 1.1 MPa for M-mode and 0.6 MPa for pulsed Doppler mode with its relatively high duty cycle (7.7 × 10−3 vs. 0.27 × 10−3 for M-mode). Reducing the duration of M-mode to 15 s (from 300 s) did not significantly reduce PCH (area, volume or depth) for some power settings, but the threshold was increased to 1.4 MPa. Pulmonary sonographers should be aware of this unique adverse bio-effect of diagnostic ultrasound and should consider reduced on-screen mechanical index settings for potentially vulnerable patients.

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Pulmonary Capillary Hemorrhage Induced by Different Imaging Modes of Diagnostic Ultrasound.

Objectives
Point-of-care lung sonography has theoretical usefulness in numerous diseases; however clinical indications and the impact of this technique have not been fully investigated. We aimed to describe the current use of point-of-care lung sonography.

Methods
A 2-year prospective observational study was performed by pulmonologists in an Italian university hospital. Techniques, indications, consequences of lung sonography, and barriers to the examination were analyzed.

Results
A total of 1150 lung sonographic examinations were performed on 951 patients. The most common indications were diagnosis and follow-up of pleural effusion in 361 cases (31%), evaluation of lung consolidation (322 [28%]), acute heart failure (195 [17%]), guide to pleural procedures (117 [10%]), pneumothorax (54 [5%]) and acute exacerbations of chronic obstructive pulmonary disease (30 [3%]). The mean duration of the examination ± SD was 6 ± 4 minutes. The transducers most frequently used were convex (746 [65%]) and linear (161 [14%]), whereas in 205 examinations (18%), both transducers were used. According to the judgment of the caring clinician, 51% of the examinations were clinically relevant.

Conclusions
Point-of-care lung sonography performed by pulmonologists is quick and feasible and could be widely used for different clinical indications with a potentially high clinical impact. The widespread use of this technique may have a relevant clinical impact in several indications.

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Point-of-Care Lung Sonography: An Audit of 1150 Examinations.

nologist-performed lung ultrasounds in an Italian university hospital [2] . We included all lung ultrasound examinations showing a B-line pattern (multiple close B lines visible in 1 single scan) in at least 1 lung field. Ultrasound findings were standardized according to guidelines [4] , and final diagnoses were adjudicated by the attending physician at patient discharge [2] . Overall, a B-line pattern was reported in 397 cases (34.5%) of the 1,150 examinations performed. Of these, 54 were obtained in children (18 females, [mean ± standard deviation] 4 ± 3 years old), 69 in adults between 19 and 64 years of age (29 females, 46 ± 13 years old), 178 in patients aged >64 years (68 females, 75 ± 5 years old), and 96 in patients >80 years (50 females, 86 ± 5 years old). Figure 1 shows that community-acquired pneumonia represents the main cause of B-line patterns in children (89%) and middle-aged adults (51%), whereas acute heart failure prevails in the elderly (37% between 64 and 80 years old, 50% if older than 80 years). However, etiologies are heterogeneous since interstitial lung diseases, lung cancer, empyema, atelectasis, pulmonary infarction, and even the normal lung may show lung areas with a B-line pattern in about half of the adult population. In conclusion, when a large population and multiple conditions are considered, we should expect that one-third of the lung ultrasound studies show a B-line pattern in at least 1 thoracic area, with etiology varying throughout different age groups. Since this pattern could be attributed to a wide range of conditions, its interpretation cannot withstand analysis of the distribution, extension, and severity of the B-line pattern together with an accurate clinical correlation. Lung ultrasound is a field of growing importance in respiratory medicine [1, 2] . B lines, previously termed ‘‘comet tails,” are vertical hyperechoic reverberations moving synchronously with the lung and represent key artifacts in interpreting pulmonary ultrasound findings [3, 4] . The physiologic basis of B lines relates to decreased lung aeration [5] , a finding that is nonspecific. Here, we aimed to explore the specific clinical diagnoses associated with the B-line pattern and their evolution with age. We therefore undertook a secondary analysis of a 2-year audit of consecutive pulmoPublished online: July 22, 2017

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Lung Ultrasound B Lines: Etiologies and Evolution with Age.

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Why Ultrasound May Ameliorate the Approach to Pneumonia in Children

Community-acquired pneumonia (CAP) is the leading cause of worldwide mortality in children. In hospitalised patients, the suspicion of pneumonia has been traditionally confirmed through chest radiography. Nowadays, the use of lung ultrasound permits a new diagnostic approach based on sonographic visualization of lung consolidations: recent studies have shown an elevated accuracy of this technique in the diagnosis of children pneumonia. Since the presence of two valuable imaging techniques, we feel the need for a comparison in strengths and limitations between radiography and lung ultrasound in the diagnosis and follow-up of children with CAP. © 2016 The Authors. Published by ACT Publishing Group Ltd.

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Simone Sferrazza Papa

Papers

Point-of-Care Lung Sonography: An Audit of 1150 Examinations.

Lung Ultrasound B Lines: Etiologies and Evolution with Age.

Why Ultrasound May Ameliorate the Approach to Pneumonia in Children

Why Ultrasound May Ameliorate the Approach to Pneumonia in Children: Dipartimento Scienze della Salute, Universitdegli Studi di Milano, Milan, Italy