Lung Ultrasonography May Provide an Indirect Estimation of Lung Porosity and Airspace Geometry

Background: Echographic vertical artifacts (B-lines) in chest ultrasonography have often been associated with pathological patterns. A scientifically sound explanation of these artifacts has not yet been proposed. Objectives: The 'spongy' nature of the lung in its liquid and solid components and the changes that take place in peripheral airspace (PAS) geometry might be the key point to understanding these phenomena. Methods: Six excised right rabbit lungs were obtained. Each lung underwent direct ultrasound evaluation in two different conditions: at complete tissue elastic recoil volume and at pulmonary expansion volume achieved by applying a constant positive pressure of 12 cm H2O. Lung volumes and densities were reported in both conditions. Histological examination was performed on three naturally collapsed lungs and on three lungs under positive pressure inflation after having been fixed in formalin solution. Results: Mean volumes of naturally collapsed lungs and fixed expanded lungs were 11.2 ± 0.36 and 44.83 ± 3.03 ml, respectively. Mean densities were 0.622 ± 0.016 and 0.155 ± 0.007 g/ml, respectively. Ultrasound evaluation of collapsed lungs showed dense vertical artifacts and a 'white lung' pattern, while the evaluation of expanded lungs showed hyperechoic line and horizontal artifacts of reflection. Histological evaluation showed a different PAS geometry in collapsed lungs caused by alveolar size reduction and shape changes with unfolded and closed units modifying the peripheral porosity of the frothy nature of the lung. Conclusions: Airspace geometry, frothy nature and porosity are the determinants of the different behavior of ultrasound interacting with the subpleural lung parenchyma. Chest ultrasound may thus be interpreted as an indirect 'estimator' of lung porosity

Educational interventions alone and combined with port protector reduce the rate of central venous catheter infection and colonization in respiratory semi-intensive care unit.

Background: Central Line-Associated BloodStream Infections (CLABSIs) are emerging challenge in Respiratory semi-Intensive Care Units (RICUs). We evaluated efficacy of educational interventions on rate of CLABSIs and effects of port protector as adjuvant tool. Methods: Study lasted 18 months (9 months of observation and 9 of intervention). We enrolled patients with central venous catheter (CVC): 1) placed during hospitalization in RICU; 2) already placed without signs of systemic inflammatory response syndrome (SIRS) within 48 h after the admission; 3) already placed without evidence of microbiologic contamination of blood cultures. During interventional period we randomized patients into two groups: 1) educational intervention (Group 1) and 2) educational intervention plus port protector (Group 2). We focused on CVC-related sepsis as primary outcome. Secondary outcomes were the rate of CVC colonization and CVC contamination. Results: Eighty seven CVCs were included during observational period. CLABSIs rate was 8.4/1000 [10 sepsis (9 CLABSIs)]. We observed 17 CVC colonizations and 6 contaminations. Forty six CVCs were included during interventional period. CLABSIs rate was 1.4/1000. 21/46 CVCs were included into Group 2, in which no CLABSIs or contaminations were reported, while 2 CVC colonizations were found. Conclusions: Our study clearly shows that both kinds of interventions significantly reduce the rate of CLABSIs. In particular, the use of port protector combined to educational interventions gave zero CLABSIs rate. Trial registration: NCT03486093 [ ClinicalTrials.gov Identifier], retrospectively registered

Artifactual Lung Ultrasonography: It Is a Matter of Traps, Order, and Disorder

When inspecting the lung with standard ultrasound B-mode imaging, numerous artifacts can be visualized. These artifacts are useful to recognize and evaluate several pathological conditions in Emergency and Intensive Care Medicine. More recently, the interest of the Pulmonologists has turned to the echographic study of the interstitial pathology of the lung. In fact, all lung pathologies which increase the density of the tissue, and do not consolidate the organ, are characterized by the presence of ultrasound artifacts. Many studies of the past have only assessed the number of vertical artifacts (generally known as B-Lines) as a sign of disease severity. However, recent observations suggest that the appearance of the individual artifacts, their variability, and their internal structure, may play a role for a non-invasive characterization of the surface of the lungs, directing the diagnoses and identifying groups of diseases. In this review, we discuss the meaning of lung ultrasound artifacts, and introduce hypothesis on the correlation between their presence and the structural variation of the sub-pleural tissue in light of current knowledge of the acoustic properties of the pleural plane

Novel aspects in diagnostic approach to respiratory patients: is it the time for a new semiotics?

Abstract Medical approach to patients is a fundamental step to get the correct diagnosis. The aim of this paper is to analyze some aspects of the reasoning process inherent in medical diagnosis in our era. Pathologic signs (anamnestic data, symptoms, semiotics, laboratory and strumental findings) represent informative phenomena to be integrated for inferring a diagnosis. Thus, diagnosis begins with “signs” and finishes in a probability of disease. The abductive reasoning process is the generation of a hypothesis to explain one or more observations (signs) in order to decide between alternative explanations searching the best one. This process is iterative during the diagnostic activity while collecting further observations and it could be creative generating new knowledge about what has not been experienced before. In the clinical setting the abductive process is not only theoretical, conversely the physical exploitation of the patient (palpation, percussion, auscultation) is always crucial. Through this manipulative abduction, new and still unexpressed information is discovered and evaluated and physicians are able “to think through doing” to get the correct diagnosis. Abductive inferential path originates with an emotional reaction (discovery of the signs), step by step explanations are formed and it ends with another emotional reaction (diagnosis). Few bedside instruments are allowed to physicians to amplify their ability to search for signs. Stethoscope is an example. Similarities between ultrasound exploration and percussion can be found. Bedside ultrasonography can be considered an external amplifier of signs, a particular kind of percussion and represents a valid example of abductive manipulation. In this searching for signs doctors act like detectives and sometimes the discovering of a strategic, unsuspected sign during abductive manipulation could represent the key point for the correct diagnosis. This condition is called serendipity. Ultrasound is a powerful tool for detecting soft, hidden, unexpected and strategic signs

Possible Role of Chest Ultrasound in the Assessment of Costo-Phrenic Angle Lesions Prior to Medical Thoracoscopy: A Retrospective Pilot Case Series

Background: Pleural malignancy (PM) and malignant pleural effusion (MPE) represent an increasing burden of diseases. Costo-phrenic angle (CPA) could be involved by malignant small nodularities or thickenings in the case of MPE. The aim of this study was to evaluate whether lung ultrasound (LUS), performed prior to medical thoracoscopy (MT), could detect pleural abnormalities in CPA not easily detectable by chest computed tomography scan (CCT). Methods: Patients suspected for PM and MPE were retrospectively recruited. Patients underwent both LUS examination with a linear array and CCT prior to diagnostic medical thoracoscopy. LUS pathological findings in CPA were compared with pathological findings detected by CCT. Findings were confirmed by subsequent MT, the gold standard for PMs. Results: Twenty-eight patients were recruited. LUS detected 23 cases of pleural abnormalities in CPA. CCT was detected 12 pleural abnormalities. Inter-rater agreement between the two techniques was minimal (Cohen’s Kappa: 0.28). MT detected PMs in CPA in 22 patients. LUS had a sensitivity of 100% and specificity of 83%. CCT had a sensitivity of 54% and specificity of 100%. A better sensitivity for CCT was reached analysing only all abnormalities > 5 mm (64.3%). Conclusions: LUS examination, in the case of PMs, could change and speed up diagnostic workup

Possible Role of Chest Ultrasonography for the Evaluation of Peripheral Fibrotic Pulmonary Changes in Patients Affected by Idiopathic Pulmonary Fibrosis—Pilot Case Series

Lung ultrasonography (LUS) provides an estimation of peripheral airspace (PAS) geometry of the lung. Altered PAS produces sonographic interstitial syndrome (SIS). Idiopathic pulmonary fibrosis (IPF) involves peripheral lung with altered PAS. The aim of the study is to correlate echographic patterns with peripheral fibrotic changes on high-resolution Chest CT scan (HRCT). Patients underwent LUS and HRCT on the same date. Four LUS patterns were described: (1) near normal; (2) SIS with predominance of reverberant artifacts; (3) SIS with vertical predominance; (4) white lung. Four HRCT grades of peripheral fibrotic infiltrates were reported: grade 1 mild; grade 2 moderate; grade 3 severe; grade 4 massive or honeycomb. LUS pattern 1 was indicative of mild to moderate fibrotic alterations in 100% of cases. LUS pattern 2 matched with HRCT grade 2 in 24 out of 30 cases (77%). Huge discordance in four cases because of large honeycomb cysts. LUS pattern 3 was indicative of severe to massive alterations in 100% of cases. LUS pattern 4 showed a heterogeneous distribution of HRCT grades, severe changes, and ground glass opacities (GGO). This preliminary work demonstrates some level of agreement between LUS patterns and HRCT grades. Limitations and methodological issues have been shown to support subsequent studies of agreement

Ultrasonography for the Diagnosis of Pneumothorax after Transbronchial Lung Cryobiopsy in Diffuse Parenchymal Lung Diseases

Background: Transbronchial lung cryobiopsy (TBLC) can be indicated in diffuse parenchymal lung diseases (DPLDs) when a confident noninvasive diagnosis cannot be made. The 2 most relevant complications of TBLC are bleeding and pneumothorax (PTX). The accuracy of chest ultrasonography (US) for the detection of PTX is higher when compared to chest X-ray (CXR) with reference to computed tomography (CT) scan as a gold standard. Objective: We evaluated the accuracy of chest US in detecting PTX after TBLC in patients with DPLDs. Methods: Patients underwent TBLC during rigid bronchoscopy in deep sedation. Cryobiopsy was performed with fluoroscopic guidance. Three hours later, patients underwent chest US and standard CXR. When there was no concordance between chest US and CXR, chest CT was required. Results: Forty-three patients were enrolled into the study. Cryobiopsy was performed in the right lung in 36 (84%) patients. PTX was diagnosed in 10 (23%) patients by CXR. There was complete agreement between radiologists interpreting CXR (k = 1, 95% CI 1). Chest US was positive for PTX in 11 (25%) patients. There was complete agreement between pulmonologists interpreting chest US (k = 1, 95% CI 1). The prevalence of PTX diagnosed by concordance of CXR and chest US was 23% (10/43, 95% CI 11.8-38.7). The sensitivity and specificity of chest US were 90% (95% CI 55.5-99.7) and 94% (95% CI 79.8-99.3), respectively. Moreover, the positive and negative predictive values were 82% (95% CI 48-98) and 97% (95% CI 84-100), respectively. Conclusion: Chest US is a highly sensitive and specific diagnostic tool for the diagnosis of PTX after TBLC