Lung ultrasound in the evaluation of pleural effusion

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.

Frequency of pleural effusion in dengue patients by severity, age and imaging modality: a systematic review and meta-analysis

BACKGROUND

Identification of pleural effusion (PE) in dengue infection is an objective measure of plasma leakage and may predict disease progression. However, no studies have systematically assessed the frequency of PE in patients with dengue, and whether this differs across age and imaging modality.

METHODS

We searched Pubmed, Embase Web of Science and Lilacs (period 1900-2021) for studies reporting on PE in dengue patients (hospitalized and outpatient). We defined PE as fluid in the thoracic cavity detected by any imaging test. The study was registered in PROSPERO (CRD42021228862). Complicated dengue was defined as hemorrhagic fever, dengue shock syndrome or severe dengue.

RESULTS

The search identified 2,157 studies of which 85 studies were eligible for inclusion. The studies (n = 31 children, n = 10 adults, n = 44 mixed age) involved 12,800 patients (30% complicated dengue). The overall frequency of PE was 33% [95%CI: 29 to 37%] and the rate of PE increased significantly with disease severity (P = 0.001) such that in complicated vs. uncomplicated dengue the frequencies were 48% and 17% (P < 0.001). When assessing all studies, PE occurred significantly more often in children compared to adults (43% vs. 13%, P = 0.002) and lung ultrasound more frequently detected PE than conventional chest X-ray (P = 0.023).

CONCLUSIONS

We found that 1/3 of dengue patients presented with PE and the frequency increased with severity and younger age. Importantly, lung ultrasound demonstrated the highest rate of detection. Our findings suggest that PE is a relatively common finding in dengue and that bedside imaging tools, such as lung ultrasound, potentially may enhance detection.

Point-of-care ultrasound thoracic “Quick Look” identifies potentially dangerous chest tube insertion sites

PURPOSE

Emergency and trauma physicians typically rely on anatomic landmarks to determine the proper intercostal space for emergent tube thoracostomy. However, physicians using this technique select a potentially dangerous insertion site too inferior in nearly one-third of cases, which have the potential to result in subdiaphragmatic puncture. We investigated a point-of-care ultrasound (POCUS) thoracic "Quick Look" procedure as a technique to allow visualization of underlying structures to avoid tube misplacement.

METHODS

We performed an observational study of adult emergency department patients and their treating physicians. The patient's emergency physician was asked to rapidly identify and mark a hypothetical tube thoracostomy insertion site on the patient's chest wall. An ultrasound fellow then performed a POCUS thoracic "Quick Look" exam with a phased-array probe placed directly over the marked site. Over one regular respiratory cycle, the identification of standard lung pattern was considered a negative scan whereas visualization of the diaphragm with underlying liver or spleen was considered a positive scan. Time for completion of the "Quick Look" scan was measured and inter-rater reliability was determined through image review by a single, blinded ultrasound director.

RESULTS

Seventy-six thoracic "Quick Look" scans were performed on patient subjects, of which 17% (13/76, 95%CI 8-26%) were positive. The average time for performing the "Quick Look" exam was 43 s (95%CI 30-57). Inter-rater reliability of the thoracic "Quick Look" was excellent (κ = 0.95).

CONCLUSION

Thoracic "Quick Look" exams performed at mock chest tube insertion sites demonstrated potentially dangerous insertions in 17% of the cases. POCUS thoracic "Quick Look" may be a rapid and reliable technique that improves safety when placing an emergent chest tube.

Ten Years of Pediatric Lung Ultrasound: A Narrative Review

Lung diseases are the most common conditions in newborns, infants, and children and are also the primary cause of death in children younger than 5 years old. Traditionally, the lung was not thought to be a target for an ultrasound due to its inability to penetrate the gas-filled anatomical structures. With the deepening of knowledge on ultrasound in recent years, it is now known that the affected lung produces ultrasound artifacts resulting from the abnormal tissue/gas/tissue interface when ultrasound sound waves penetrate lung tissue. Over the years, the application of lung ultrasound (LUS) has changed and its main indications in the pediatric population have expanded. This review analyzed the studies on lung ultrasound in pediatrics, published from 2010 to 2020, with the aim of highlighting the usefulness of LUS in pediatrics. It also described the normal and abnormal appearances of the pediatric lung on ultrasound as well as the benefits, limitations, and possible future challenges of this modality.

Ultrasound for Pleural Disease. Beyond a Pocket of Pleural Fluid

The evolution of pleural disease imaging modalities through the years has helped the scientific community understand and treat various disease states. Ultrasound (US) has been an image modality that has reigned superior to those used in the past such as chest X-ray and computed tomographic scan in terms of cost effectiveness, portability, and reduction in unwarranted radiation exposure to patients. Here we provide a succinct review of US use in pleural disease including imaging techniques, identifying safe pleural space for access, and predicting pleural fluid volume and etiology along with specificities regarding trapped lung identification and pleural mass biopsy. We believe bedside chest US is an adjunct to the physical exam adding superior diagnostic abilities. Further research is warranted in more specific aspects of sonographic use such as in fibrinolytic therapy management, evaluation for trapped lung, and the utility of specific modes like the color flow Doppler.

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.

Lung ultrasound compared to chest X-ray for the diagnosis of CAP in children

BACKGROUND

Community-acquired pneumonia (CAP) represents one of the most common infectious diseases among children. Diagnosis of CAP is mainly clinical. Chest X-ray (CXR) remains the gold standard for the diagnosis in severe or controversial conditions. Recently, some authors have focused on the application of ultrasound in lung diseases but the role of lung ultrasound (LUS) in the diagnosis of CAP is still debated. We aimed to study the concordance between LUS and CXR in evaluating specific signs of CAP. As a secondary aim, we sought to determine the sensitivity and specificity of LUS in CAP diagnosis compared with CXR. Finally, we evaluated the role of LUS during the follow up.

METHODS

We enrolled 68 children (<16 years old) hospitalized from October 2018 to September 2019 with a clinical and radiological diagnosis of CAP (cases: N = 41), or with no respiratory diseases (controls: N = 27), in whom a CXR was performed for clinical indications. All the children underwent LUS during hospitalization. The average time needed to perform LUS was 5-10 min for each child, and 19/41 cases were re-evaluated by LUS and CXR 30 days after discharge.

RESULTS

Lung ultrasound confirmed CAP diagnosis in 40/41 patients. Concordance between the two techniques was K = 0.88 for the right lung and K = 0.70 for the left lung. Lung ultrasound showed a sensitivity of 97% and a specificity of 96% compared with CXR. At the follow up, sensitivity increased to 100% while specificity was 94%.

CONCLUSIONS

Our study showed a potential benefit of LUS compared with CXR in the diagnosis and the follow up of CAP.

Recommendations for Lung Ultrasound in Internal Medicine

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.

Management of Pleural Effusions in the Emergency Department

BACKGROUND

In symptomatic patients, admitted in emergency department for acute chest pain and dyspnea, who require an urgent treatment, a rapid diagnosis and prompt management of massive pleural effusion or hemothorax can be lifesaving.

AIM

The aim of this review was to summarize the current diagnostic and therapeutic approaches for the management of the main types of pleural effusions that physicians can have in an emergency department setting.

METHODS

Current literature about the topic was reviewed and critically reported, adding the experience of the authors in the management of pleural effusions in emergency settings.

RESULTS

The paper analyzed the main types of pleural effusions that physicians can have to treat. It illustrated the diagnostic steps by the principal radiological instruments, with a particular emphasis to the role of ultrasonography, in facilitating diagnosis and guiding invasive procedures. Then, the principal procedures, like thoracentesis and insertion of small and large bore chest drains, are indicated and illustrated according to the characteristics and the amount of the effusion and patient clinical conditions.

CONCLUSION

The emergency physician must have a systematic approach that allows rapid recognition, clinical cause identification and definitive management of potential urgent pleural effusions.

Perioperative Transthoracic Lung Ultrasound for Assessment of Pulmonary Outcome in Adolescent Idiopathic Scoliosis Patients: Prospective, Observational Pilot Study

The purpose of study was to evaluate the perioperative lung ultrasound findings of patients undergoing scoliosis correction. LUS examination was performed examined three 3 times for each patient: 20 min after starting mechanical ventilation of the lungs(preoperative), after surgery when the patient was placed in the supine position(postoperative), and 20 min after arrival in the post-anaesthesia care unit. Arterial blood gas analyses, mechanical ventilation parameters, peripheral oxygen saturation(SpO2) were also checked. Twenty-six patients completed the study. The changes of LUS score(20 min) was significantly negatively correlated with the partial pressure of arterial oxygen(PaO2)/fraction of inspired oxygen(FiO2) ratio change(P = 0.039, r = −0.40). The change in mean convex side LUS score was significantly greater than that of the concave side as determined by two-factor repeated measures analysis of variance(p = 0.001). Multiple regression analysis revealed perioperative LUS change was the significant factor related to the oxygen index change (p = 0.042). One case of pneumothorax was diagnosed and pleural thickening more than 5 mm was detected in 8 patients and five patients of those were diagnosed pleural effusion and performed thoracentesis after surgery. Postoperative increase of LUS score was related with deteriorating of oxygenation at one day after surgery, and it suggests that lung ultrasound allows prediction of postoperative hypoxia and facilitates the diagnosis of pulmonary complications at operation room in AIS patients.

A Sensor for Spirometric Feedback in Ventilation Maneuvers during Cardiopulmonary Resuscitation Training

This work proposes adapting an existing sensor and embedding it on mannequins used in cardiopulmonary resuscitation (CPR) training to accurately measure the amount of air supplied to the lungs during ventilation. Mathematical modeling, calibration, and validation of the sensor along with metrology, statistical inference, and spirometry techniques were used as a base for aquiring scientific knowledge of the system. The system directly measures the variable of interest (air volume) and refers to spirometric techniques in the elaboration of its model. This improves the realism of the dummies during the CPR training, because it estimates, in real-time, not only the volume of air entering in the lungs but also the Forced Vital Capacity (FVC), Forced Expiratory Volume (FEVt) and Medium Forced Expiratory Flow (FEF_20–75%). The validation of the sensor achieved results that address the requirements for this application, that is, the error below 3.4% of full scale. During the spirometric tests, the system presented the measurement results of (305 ± 22, 450 ± 23, 603 ± 24, 751 ± 26, 922 ± 27, 1021 ± 30, 1182 ± 33, 1326 ± 36, 1476 ± 37, 1618 ± 45 and 1786 ± 56) × 10⁻⁶ m³ for reference values of (300, 450, 600, 750, 900, 1050, 1200, 1350, 1500, 1650 and 1800) × 10⁻⁶ m³, respectively. Therefore, considering the spirometry and pressure boundary conditions of the manikin lungs, the system achieves the objective of simulating valid spirometric data for debriefings, that is, there is an agreement between the measurement results when compared to the signal generated by a commercial spirometer (Koko brand). The main advantages that this work presents in relation to the sensors commonly used for this purpose are: (i) the reduced cost, which makes it possible, for the first time, to use a respiratory volume sensor in medical simulators or training dummies; (ii) the direct measurement of air entering the lung using a noninvasive method, which makes it possible to use spirometry parameters to characterize simulated human respiration during the CPR training; and (iii) the measurement of spirometric parameters (FVC, FEVt, and FEF_20–75%), in real-time, during the CPR training, to achieve optimal ventilation performance. Therefore, the system developed in this work addresses the minimum requirements for the practice of ventilation in the CPR maneuvers and has great potential in several future applications.

Ultrasound of the pediatric chest

Cross-sectional imaging modalities like MRI and CT provide images of the chest which are easily understood by clinicians. However, these modalities may not always be available and are expensive. Lung ultrasonography (US) has therefore become an important tool in the hands of clinicians as an extension of the clinical exam, which has been underutilized by the radiologists. Reinforcement of the ALARA principle along with the dictum of "Image gently" have resulted in increased use of modalities which do not require radiation. Hence, ultrasound, which was earlier being used mainly to confirm the presence of pleural effusion as well as evaluate it and differentiate solid from cystic masses, is now being used to evaluate the lung as well. This review highlights the utility of ultrasound of the paediatric chest. It also describes the normal and abnormal appearances of the paediatric lung on ultrasound as well as the advantages and limitations of this modality.

Sonographic Indicators for Treatment Choice and Follow-Up in Patients with Pleural Effusion

Aim

The aim of this study was to evaluate the role of thoracic sonography in treatment of pleural effusions and to identify sonographic indicators for surgical intervention.

Materials and Methods

This study included 378 patients with pleural effusions. US characteristics of effusions as the echo structure and pleural thickening were analyzed. Regarding the US finding, the diagnostic or therapeutic procedure was performed.

Results

The study included 267 male and 111 female patients, an average of 56.7 years. Infection was the most frequent cause of effusion. Two hundred sixty-nine patients had loculated and 109 free pleural effusion. Most frequent echo structure of loculated effusion was complex septate, whereas free effusion was mostly anechoic. Successful obtaining of the pleural fluid without real-time guidance was in 88% and under real-time guidance in 99% patients (p < 0.012). There was no significant difference in success rate between free and loculated effusion and regarding the echo structure (p=0.710 and 0.126, respectively). Complete fluid removal after serial thoracentesis or drainage was achieved in 86% patients. Forty-five patients with significantly thicker pleural peel and impairment of the diaphragmatic function than remaining of the group (p < 0.001) underwent surgery. Open thoracotomy and decortication was more frequently performed in patients with completely fixed diaphragm and complex, dominantly septated effusions. There is no significant difference in US parameters comparing to patients underwent VATS, but the number of VATS is too small for valid conclusion.

Conclusion

Thoracic sonography is a very useful tool in the evaluation of clinical course and treatment options in patients with pleural effusions of a different origin.

Utility of Perioperative Lung Ultrasound in Pediatric Cardiac Surgery

Background

Pediatric cardiac patients are at risk for perioperative respiratory insufficiency. The objective of this study was to assess the utility of perioperative lung ultrasound examination in pediatric cardiac surgery.

Methods

In this randomized, controlled trial, children (5 yr old or younger) undergoing cardiac surgery were allocated into a control (n = 61) or intervention (n = 61) group. The control group received only lung ultrasound examinations at the end of surgery and 6 to 12 h after surgery. The intervention group received lung ultrasound examinations and an ultrasound-guided recruitment maneuver depending on ultrasound findings after inducing anesthesia, at the end of surgery, and 6 to 12 h after surgery. Primary outcomes were incidences of intra- and postoperative desaturation, and postoperative pulmonary complications. Multiple comparisons were corrected (P ≤ 0.017) in the primary outcome analysis.

Results

Of the 120 children included in the analysis, postoperative desaturation (64% vs. 27%; P &lt; 0.001; odds ratio [OR], 0.210; 95% CI, 0.097 to 0.456) occurred more in the control group. The incidences of intraoperative desaturation (36% vs. 19%; P = 0.033; OR, 0.406; 95% CI, 0.176 to 0.939) and postoperative pulmonary complications (12% vs. 3%; P = 0.093; OR, 0.271; 95% CI, 0.054 to 1.361) were similar between the groups. Lung ultrasound scores were better in the intervention group than in the control group. Duration of mechanical ventilation was longer in the control group than in the intervention group (38 ± 43 vs. 26 ± 25 h; 95% CI of mean difference, 0 to 25; P = 0.048).

Conclusions

Perioperative lung ultrasound examination followed by ultrasound-guided recruitment maneuver helped decrease postoperative desaturation events and shorten the duration of mechanical ventilation in pediatric cardiac patients.

Validation of equations for pleural effusion volume estimation by ultrasonography

Purpose

To validate the accuracy of previously published equations that estimate pleural effusion volume using ultrasonography.

Methods

Only equations using simple measurements were tested. Three measurements were taken at the posterior axillary line for each case with effusion: lateral height of effusion (H), distance between collapsed lung and chest wall (C) and distance between lung and diaphragm (D). Cases whose effusion was aspirated to dryness were included and drained volume was recorded. Intra-class correlation coefficient (ICC) was used to determine the predictive accuracy of five equations against the actual volume of aspirated effusion.

Results

46 cases with effusion were included. The most accurate equation in predicting effusion volume was (H + D) × 70 (ICC 0.83). The simplest and yet accurate equation was H × 100 (ICC 0.79).

Conclusion

Pleural effusion height measured by ultrasonography gives a reasonable estimate of effusion volume. Incorporating distance between lung base and diaphragm into estimation improves accuracy from 79% with the first method to 83% with the latter.

Ultrasound in the management of pleural disease

INTRODUCTION

Pleural disease encompasses a large range of conditions, is a common presentation to the acute medical take and often requires comprehensive investigation and treatment. Ultrasound is well recognised as a useful investigative tool in pleural disease especially in the field of pleural effusion, pleural thickening and interventional procedures. Thoracic ultrasound (TUS) has gained widespread use by physicians as evidence has shown a reduced rate of complications when performing pleural procedures with ultrasound guidance. Areas covered: This article will review studies assessing the role of TUS in the management of pleural disease and examine ongoing research into how TUS could advance our knowledge and understanding over the next decade. Expert commentary: Physician lead thoracic ultrasound has become commonplace over the last decade, and now represents a minimum standard of safety in conducting the majority of 'bedside' pleural procedures. The current evidence points to important diagnostic and procedural roles of the use of bedside thoracic ultrasound. In the future, research developments are likely to lead to the use of thoracic ultrasound in prognostication, targeted treatment and understanding pathogenesis in pleural disease.

Strong correlation between lung ultrasound and chest computerized tomography imaging for the detection of acute lung injury/acute respiratory distress syndrome in rats

BACKGROUND

Lung ultrasound (LUS) is a clinical imaging technique for diagnosing acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). In humans and several large animals, LUS demonstrates similar specificity and sensitivity to computerized tomography (CT) scanning. Current study evaluated the degree of agreement between LUS and CT imaging in characterizing ALI/ARDS in rats.

METHODS

Thirty male Sprague-Dawley rats were imaged by LUS before randomization into three groups to receive intratracheal saline, 3 or 6 mg/kg LPS respectively (n=10). LUS and CT imaging was conducted 2 hours after instillation. Cross table analyses and kappa statistics were used to determine agreement levels between LUS and CT assessments of lung condition.

RESULTS

Before instillation, rats presented with a largely A-pattern in LUS images, however, a significantly increase B-lines were observed in all groups after instillation and showed dose response to LPS or to saline. One rat treated with 6 mg/kg lipopolysaccharide (LPS) presented with lung consolidation. The agreement between the LUS and the CT in detecting the main characteristics of ALI/ARDS in rat was strong (r=0.758, P<0.01, k=0.737).

CONCLUSIONS

In conclusion, LUS detects ALI/ARDS with high agreement with micro PET/CT scanning in a rat model, suggesting that LUS represents a positive refinement in rat ALI/ARDS disease models.