Andrea Smargiassi

The role of chest ultrasonography in the management of respiratory diseases: document II

Chest ultrasonography can be a useful diagnostic tool for respiratory physicians. It can be used to complete and widen the general objective examination also in emergency situations, at the patient’s bedside. The aim of this document is to promote better knowledge and more widespread use of thoracic ultrasound among respiratory physicians in Italy.This document II is focused on advanced approaches to chest ultrasonography especially in diagnosing sonographic interstitial syndrome with physical hypotheses about the genesis of vertical artifacts, differential diagnosis of cardiogenic pulmonary edema and non-cardiogenic pulmonary edema, raising diagnostic suspicion of pulmonary embolism, ultrasound characterization of lung consolidations and the use of ultrasonography to guide procedural interventions in pulmonology.Finally, document II focuses on chest ultrasonography as useful diagnostic tool in neonatal and pediatric care.

Ex Vivo Lung Sonography: Morphologic-Ultrasound Relationship

Ultrasound (US) interstitial syndrome is a sonographic lung pattern characterized by the presence of acoustic artifacts (B-lines and white lung). The purpose of this study was to demonstrate how interstitial syndrome is determined by acoustic interactions in lungs of variable density and in healthy organs deflated to a nonphysiologic level of density. Normal rabbit lungs were studied ex vivo by US at varying known degrees of inflation, and their histologic appearances were described. In this experimental setting, US interstitial syndrome recognizes a mechanism related to tissue density or porosity. Artifacts (B-lines and white lung) appear in the normal rabbit lung through air-dependent increases in density. As in pathologic conditions, US interstitial syndrome can be reproduced in histologically normal lungs that are deflated to a critical level (>0.45 g/mL) of density, which is not achievable under physiologic conditions.

Ultrasonographic Assessment of the Diaphragm in Chronic Obstructive Pulmonary Disease Patients: Relationships with Pulmonary Function and the Influence of Body Composition - A Pilot Study

Background: Skeletal muscle weakness with loss of fat-free mass (FFM) is one of the main systemic effects of chronic obstructive pulmonary disease (COPD). The diaphragm is also involved, leading to disadvantageous conditions and poor contractile capacities. Objectives: We measured the thickness of the diaphragm (TD) by ultrasonography to evaluate the relationships between echographic measurements, parameters of respiratory function and body composition data. Methods: Thirty-two patients (23 males) underwent (1) pulmonary function tests, (2) echographic assessment of TD in the zone of apposition at various lung volumes, i.e. TD at residual volume (TDRV), TD at functional residual capacity (TDFRC) and TD at total lung capacity (TDTLC), and (3) bioelectrical body impedance analysis. The BMI and the BODE (BMI-Obstruction-Dyspnea-Exercise) index values were reported. Results: TDRV, TDFRC and TDTLC measured 3.3, 3.6 and 6 mm, respectively, with good intraobserver reproducibility (0.97, 0.97 and 0.96, respectively). All the TDs were found to be related to FFM, with the relationship being greater for TDFRC (r2 = 0.39 and p = 0.0002). With regard to lung volumes, inspiratory capacity (IC) was found to be closely related to TDTLC (r2 = 0.42 and p = 0.0001). The difference between TDTLC and TDRV, as a thickening value (TDTLCRV), was closely related to FVC (r2 = 0.34 and p = 0.0004) and to air-trapping indices (RV/TLC, FRC/TLC and IC/TLC): the degree of lung hyperinflation was greater and the TDTLCRV was less. Finally, we found a progressive reduction of both thicknesses and thickenings as the severity of IC/TLC increased, with a significant p value for the trend in both analyses (p = 0.02). Conclusions: Ultrasonographic assessment of the diaphragm could be a useful tool for studying disease progression in COPD patients, in terms of lung hyperinflation and the loss of FFM.

Role of ultrasound-guided transbronchial biopsy in the diagnosis of peripheral pulmonary lesions.

INTRODUCTION Endobronchial ultrasound (EBUS) can be used as an alternative to fluoroscopy to visualize a peripheral pulmonary lesion (PPL) and to provide an image guidance for transbronchial biopsy (TBB). The aim of this study was to verify the accuracy of EBUS-guided TBB in the diagnosis of PPLs. METHODS All the patients with CT-scan evidence of PPL who underwent bronchoscopy with EBUS in the period between 2008 and 2011 were retrospectively evaluated. EBUS was performed using a radial-type miniature ultrasound probe. Once obtained an EBUS image of the PPL, we measured the distance of the PPL from the outer orifice of the working channel of the bronchoscope in order to perform TBB at PPL site. RESULTS A total of 662 patients were examined. The mean diameter of lesions was 36 ± 20 mm. PPLs were visualized in 494 patients (75%) and the TBB was performed in 479 patients. Thirty-two patients were lost in follow-up and data from 447 patients were analyzed. TBB results were 255 cancers and 192 non-malignant lesions. The final diagnosis reported was 359 cases of cancer and 88 of benign lesion. EBUS-guided TBB had a sensitivity of 71% for the diagnosis of cancer, a negative predictive value of 46% and an overall diagnostic accuracy of 77%. CONCLUSIONS These data obtained from a large series of patients and using an original method show that EBUS represents a valid support to bronchoscopy and that the EBUS-guided TBB has a high diagnostic yield in the diagnosis of PPLs.

Ultrasound-guided pleural puncture in supine or recumbent lateral position - feasibility study

BackgroundThe aim of this study is to evaluate feasibility, safety and efficacy of accessing the pleural space with the patient supine or in lateral recumbent position, under constant ultrasonic guidance along the costophrenic sinus.MethodsAll patients with pleural effusion, referred to thoracentesis or pleural drainage from February 2010 to January 2011 in two institutions, were drained either supine or in lateral recumbent position through an echomonitored cannulation of the costophrenic sinus. The technique is described in detail and an analysis of safety and feasibility is carried out.ResultsOne hundred and one thoracenteses were performed on 76 patients and 30 pigtail catheters were inserted in 30 patients (for a total of 131 pleural procedures in 106 patients enrolled). The feasibility of the procedures was 100% and in every case it was possible to follow real time needle tip passage in the pleural space.Ninety eight thoracenteses (97%) and all catheter drainages were successfully completed. Four thoracenteses were stopped because of the appearance of complications while no pigtail drainage procedure was stopped. After 24 hour follow up, one chest pain syndrome (1.3% of completed thoracenteses) and two pneumothoraces (1.4%) occurred. The mean acquisition time of pleural space was 76 ± 9 seconds for thoracentesis and 185 ± 46 seconds for drainage insertion (p < 0.05).ConclusionsThis study highlights the safety and efficacy of this technique of real time echo-monitored pleural space puncture, that offers a more comfortable patient position, an easier approach for the operator, a very low rate of complications with short acquisition time of pleural space.

On the Physical Basis of Pulmonary Sonographic Interstitial Syndrome.

ung sonography is widely accepted and used in emergency medicine and critical care.1–5 Moreover, many pulmonologists are interested in chest sonography for the study of pleural diseases and are increasingly discovering a role for sonography in parenchymal lung diseases.6–9 For those physicians who are devoted to chest sonography, a clear dichotomy between usual sonography and aerated tissue sonography is obvious. Pleural sonography is effective under most circumstances, whereas lung sonography is effective only when certain physical properties of the lung (eg, the bubble system) are lost. In other words, the lung is sonographically explorable only when it is physically comparable with soft tissue. In particular, when using lung sonography, a lung that contains dispersed air and has a density that is not comparable with the density of water does not show anatomic images but rather artifactual images.10 Therefore, lung artifacts are quite consistent with the physical properties of a lung that is not fully consolidated rather than with an anatomic image.11 The physical properties of the subpleural nonconsolidated lung are the hallmarks of many pulmonary diseases, which can be roughly grouped into “interstitial diseases.” If an ultrasound imaging system is used, all of these pulmonary diseases are classified by the generic term “sonographic interstitial syndrome” (B-lines with variable arrangements along the pleural line).5 According to this view, it is not surprising that since 1997,12 vertical lung artifacts, commonly named B-lines, have been associated with pathologic conditions ranging from pulmonary edema to fibrosis, which are characterized by a change in the subpleural physical features in terms of full and empty spaces.11 Gino Soldati, MD Emergency Medicine Unit Valle del Serchio General Hospital Lucca, Italy

Ultrasonography in lung pathologies: new perspectives.

BackgroundNowadays, ultrasound techniques have not gained importance in the diagnosis and monitoring of lung pathologies yet because of the high mismatch in acoustic impedance between air and intercostal tissues. However, it is evident that B-mode imaging provides important information on pulmonary tissue, although in the form of image artifacts.FindingsNotwithstanding medical evidences, there exists no ultrasound-based method dedicated to the lung, hampering de facto the full exploitation of ultrasound potentials. A chance is given by the experience acquired in other fields, where acoustic attenuation is used to estimate concentrations of suspended particles in liquids and of air-bubbles in aerated foods.ConclusionsCustom hardware must be developed since commercial echographic equipment has been optimized to work with low acoustic impedance mismatches, and, in general, does not provide the primitive radiofrequency (RF) signals nor the possibility to tune key acquisition parameters such as ultrasound carrier frequency and pulse bandwidth, which are surely needed for our application.

Ultrasound Analysis of Diaphragm Kinetics and the Diagnosis of Airway Obstruction: The Role of the M-Mode Index of Obstruction1

Diaphragm motion in forced expiration can be analyzed using M-mode ultrasound in an anterior subcostal approach. Maximum expiratory diaphragmatic excursion (EDEMax) and forced expiratory diaphragmatic excursion in the first second (FEDE1) are considered the physiopathological analogues of vital capacity (VC) and forced expiratory volume in the first second (FEV1). As the FEV1/VC % ratio is used as a marker of obstruction, our aim was to determine if the ratio FEDE1/EDEMax (M-mode index of obstruction [MIO]) differs between healthy subjects and patients with airway obstruction. One hundred twenty-four outpatients were examined by diaphragm ultrasound after spirometry. The MIO, expressed as the mean ± standard deviation (range), was 87.08 ± 6.64 (72.84-100) in the healthy group (N = 61) and 67.09 ± 12.49 (33.33-91.30) in the group with obstructed airways (N = 63). The difference between the two groups was significant (p < 0.0001), and MIO was significantly correlated with FEV1/VC (p < 0.0001). A MIO <77 was identified as a possibile cutoff for suspecting an obstructive spirometric pattern with a 95.5% positive predictive value. The MIO can be interpreted as a speed index of diaphragmatic relaxation that seems to be slower in obstructed patients and could be used to screen for obstructed airway diseases.

Description of free-flowing pleural effusions in medical reports after echographic assessment.

Background: There is no standardized and accepted grading system to qualitatively assess pleural effusion by chest ultrasound. In clinical practice there are pleural effusions (PE) that should not be drained but they need to be subsequently assessed during medical therapy. Methods: We propose a method to standardize medical reports dealing with free flowing PE using easy anatomic landmarks (level of compression/atelectasis of the lobes; evaluation of the diaphragm dome; possibility to visualize pulmonary hilum) and number of intercostal spaces through which its possible to check the pleural fluid along the postero-axillary line with the patient sitting or lying supine (Smargiassi A. et al. Respiration 2013 (ahead of print)). ![Figure][1] 62 PE were evaluated with this method. Results: Grade 1: 9 PE; Grade 2: 7 PE; Grade 3: 26 PE; Grade 4: 11 PE; Grade 5: 6 PE; Grade 6: 3 PE. Pleural procedures (PP) were immediately performed In 68% of cases. The decision to perform PP depended on both the extension and the clinical conditions and the echographic features of the fluid. PE grade 1, 2 and 3 didn’t undergo immediate PP when related to pneumonia or cardiac/renal failure but followed up during medical therapy. Only if upgraded, PP were required. Conclusion: Accepting these grades we can contribute to achieve uniformity in description of free flowing PE at ultrasound examination and follow-up. [1]: pending:yes

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.