Lung Ultrasound for Critically Ill Patients

Lung-ultrasound objective structured assessment of technical skills (LUS-OSAUS): utility in the assessment of lung-ultrasound trained medical undergraduates

Purpose

Recently, some attempts have been made to integrate lung ultrasound (LUS) teaching into medical curricula. However, current education studies of LUS are extremely heterogeneous due to the lack of evidence-based guidelines on LUS education. In particular, the assessment of competencies is poorly standardized and mostly relies on non-validated scales. A new validated tool, the objective structured assessment of lung ultrasound skills (LUS-OSAUS), has the potential to overcome these limitations. Therefore, we adopted the LUS-OSAUS tool to assess the competencies of a group of LUS-trained undergraduates. Existing no prior practical applications of the LUS-OSAUS, our aim was to investigate the practical utility of this tool and its applicability in the evaluation of US-trained medical students.

Methods

Eight undergraduates (two males, six females) were enrolled on a voluntary basis to receive a theoretical and practical training in LUS. Once completed their training, each student performed an LUS examination on a different patient hospitalized for respiratory symptoms. The same eight patients were also scanned by a senior resident in emergency medicine for a comparison with students’ results. Students and the senior resident were tested by an examiner using the LUS-OSAUS tool. We compared the scores obtained by operators in all areas of competence of the LUS-OSAUS, the total scores, and the time needed to complete the sonographic task.

Results

Median students’ score in the single items of the scale was significantly lower than the ones obtained by the senior resident (4.0 [3.3–5.0] vs. 5.0 [5.0–5.0]; p < 0.0001). Students scored significantly lower than the senior resident in each item, except for B-line identification, choice of the correct transducer, and suggested focused questions. Median total score was also lower for students compared to the senior resident (70.5 [61.0–74.8] vs. 84.0 [83.5–84.3] (p = 0.0116). Median time required to complete the examination was significantly higher for students (14.1 [12.8–16.1] vs. 4.7 [3.9–5.2] min, p = 0.0117).

Conclusions

The LUS-OSAUS tool allowed for a standardized and comprehensive assessment of student’s competencies in lung ultrasound, and helped to discriminate their level of expertise from that of a more experienced operator. The scale also specifically tests the theoretical knowledge of trainees, thus making redundant the use of questionnaires designed for this purpose.

Electronic supplementary material

The online version of this article (10.1007/s40477-020-00454-x) contains supplementary material, which is available to authorized users.

[Lung Ultrasound: new Opportunities for a Cardiologist]

This review focused on ultrasound examination of lungs, a useful complement to transthoracic echocardiography (EchoCG), which is superior to chest X-ray in the diagnostic value. The lung acoustic window always remains open and allows obtaining high-quality images in most cases. For a cardiologist, the major points of the method application are determination of pleural effusion and lung congestion. This method has a number of advantages: it is time-saving; cost-effective; portable and accessible; can be used in a real-time mode; not associated with radiation; reproducible; and highly informative. The ultrasound finding of wet lungs would indicate threatening, acute cardiac decompensation long before appearance of clinical, auscultative, and radiological signs of lung congestion. Modern EchoCG should include examination of the heart and lungs as a part of a single, integrative ultrasound examination.

From bedside to bench: lung ultrasound for the assessment of pulmonary edema in animal models

Traditionally, the lung has been excluded from the ultrasound organ repertoire and, hence, the application of lung ultrasound (LUS) was largely limited to a few enthusiastic clinicians. Yet, in the last decades, the recognition of the previously untapped diagnostic potential of LUS in intensive care medicine has fueled its widespread use as a rapid, non-invasive and radiation-free bedside approach with excellent diagnostic accuracy for many of the most common causes of acute respiratory failure, e.g., cardiogenic pulmonary edema, pneumonia, pleural effusion and pneumothorax. Its increased clinical use has also incited attention for the potential usefulness of LUS in preclinical studies with small animal models mimicking lung congestion and pulmonary edema formation. Application of LUS to small animal models of pulmonary edema may save time, is cost-effective, and may reduce the number of experimental animals due to the possibility of serial evaluations in the same animal as compared with traditional end-point measurements. This review provides an overview of the emerging field of LUS with a specific focus on its application in animal models and highlights future perspectives for LUS in preclinical research.

Lung Ultrasonography and Cardiac Surgery: A Narrative Review

Pulmonary complications are common after cardiac surgery and are closely related to postoperative heart failure and adverse outcomes. Lung ultrasonography (LUS) is currently a widely accepted diagnostic approach with well-established methodology, nomenclature, accuracy, and prognostic value in numerous clinical conditions. The advantages of LUS are universally recognized and include bedside applicability, high diagnostic sensitivity and reproducibility, no radiation exposure, and low cost. However, routine perioperative ultrasonography during cardiac surgery generally is limited to echocardiography, diagnosis of pleural effusion, and as a diagnostic tool for postoperative complications in different organs, and few studies have explored the clinical outcomes in relation to LUS among cardiac patients. This narrative review presents the clinical evidence regarding LUS application in intensive care and during the perioperative period for cardiac surgery. Furthermore, this review describes the methodology and the diagnostic and prognostic accuracies of LUS. A summary of ongoing clinical trials evaluating the clinical outcomes related to LUS also is provided. Finally, this review discusses the rationale for upcoming clinical research regarding whether routine use of LUS can modify current intensive care practice and potentially affect the clinical outcomes after cardiac surgery.

Not all abolished lung sliding are pneumothorax: the case of a particular lung atelectasis

INTRODUCTION

Lung ultrasound (LUS) is expanding from the field of emergency medicine, also to the pneumological specialist field, becoming part of the diagnostic procedure of lung consolidation.

CASE PRESENTATION

A 78-year-old male was admitted to our emergency department for exertional dyspnea. LUS was performed, thus showing at right hemitorax air interface, A lines pattern, pleural sliding abolished on the whole hemitorax, thus suggesting a pneumothorax, but no evidence of lung point. A scan of lower lung segment showed an absence of the diaphragmatic excursion, suggestive for hemiparalysis of the diaphragm muscle, then confirmed by a subcostal scan. Moreover, at the lower segment of right hemitorax there was mild pleural effusion allowing the visualization of a round-shaped parenchymal consolidation with the absence of air bronchograms.

CONCLUSIONS

LUS allowed the visualization of a particular and rare disease such as anthracosis-associated rounded atelectasis, thus leading to a more correct and faster patient management.

Should the ultrasound probe replace your stethoscope? A SICS-I sub-study comparing lung ultrasound and pulmonary auscultation in the critically ill

Background

In critically ill patients, auscultation might be challenging as dorsal lung fields are difficult to reach in supine-positioned patients, and the environment is often noisy. In recent years, clinicians have started to consider lung ultrasound as a useful diagnostic tool for a variety of pulmonary pathologies, including pulmonary edema. The aim of this study was to compare lung ultrasound and pulmonary auscultation for detecting pulmonary edema in critically ill patients.

Methods

This study was a planned sub-study of the Simple Intensive Care Studies-I, a single-center, prospective observational study. All acutely admitted patients who were 18 years and older with an expected ICU stay of at least 24 h were eligible for inclusion. All patients underwent clinical examination combined with lung ultrasound, conducted by researchers not involved in patient care. Clinical examination included auscultation of the bilateral regions for crepitations and rhonchi. Lung ultrasound was conducted according to the Bedside Lung Ultrasound in Emergency protocol. Pulmonary edema was defined as three or more B lines in at least two (bilateral) scan sites. An agreement was described by using the Cohen κ coefficient, sensitivity, specificity, negative predictive value, positive predictive value, and overall accuracy. Subgroup analysis were performed in patients who were not mechanically ventilated.

Results

The Simple Intensive Care Studies-I cohort included 1075 patients, of whom 926 (86%) were eligible for inclusion in this analysis. Three hundred seven of the 926 patients (33%) fulfilled the criteria for pulmonary edema on lung ultrasound. In 156 (51%) of these patients, auscultation was normal. A total of 302 patients (32%) had audible crepitations or rhonchi upon auscultation. From 130 patients with crepitations, 86 patients (66%) had pulmonary edema on lung ultrasound, and from 209 patients with rhonchi, 96 patients (46%) had pulmonary edema on lung ultrasound. The agreement between auscultation findings and lung ultrasound diagnosis was poor (κ statistic 0.25). Subgroup analysis showed that the diagnostic accuracy of auscultation was better in non-ventilated than in ventilated patients.

Conclusion

The agreement between lung ultrasound and auscultation is poor.

Trial registration

NCT02912624. Registered on September 23, 2016.

Lung Ultrasound for the Diagnosis and Management of Acute Respiratory Failure

For critically ill patients with acute respiratory failure (ARF), lung ultrasound (LUS) has emerged as an indispensable tool to facilitate diagnosis and rapid therapeutic management. In ARF, there is now evidence to support the use of LUS to diagnose pneumothorax, acute respiratory distress syndrome, cardiogenic pulmonary edema, pneumonia, and acute pulmonary embolism. In addition, the utility of LUS has expanded in recent years to aid in the ongoing management of critically ill patients with ARF, providing guidance in volume status and fluid administration, titration of positive end-expiratory pressure, and ventilator liberation. The aims of this review are to examine the basic foundational concepts regarding the performance and interpretation of LUS, and to appraise the current literature supporting the use of this technique in the diagnosis and continued management of patients with ARF.

Emergence of Alveolar Consolidations in Serial Lung Ultrasound and Diagnosis of Ventilator-Associated Pneumonia

BACKGROUND

Lung ultrasound (LUS) has been reported as a promising diagnostic tool for ventilator-associated pneumonia (VAP), but patients with previous lung parenchyma commitment have been not studied.

PURPOSE

To evaluate whether the emergence of sonographic consolidations, rather than their presence, can improve the VAP diagnosis in a sample including patients with previous lung parenchyma diseases.

METHODS

Patients who completed 48 hours of mechanical ventilation were prospectively studied with daily LUS examinations. We checked the emergence of different consolidation types on the eve and on the day of a clinical suspicion of VAP. We elaborated an algorithm considering, sequentially, the emergence of (1) subpleural consolidations in anterior lung regions on the eve of suspicion; (2) lobar/sublobar consolidation in anterior lung regions on the day of suspicion; (3) lobar/sublobar consolidation with dynamic air bronchograms on the day of suspicion; and (4) any other lobar/sublobar consolidation on the day of suspicion in association with a positive Gram smear of endotracheal aspirate.

RESULTS

Of the 188 included patients, 60 were suspected and 33 confirmed VAP. The presence of sonographic consolidations at the clinical suspicion had no diagnostic value for VAP. The emergence of subpleural consolidations in anterior lung regions on the eve of suspicion had specificity of 95% (95% confidence interval [CI], 79%-99%). The emergence of lobar/sublobar consolidations in anterior lung regions on the day of suspicion had specificity of 100% (95% CI, 87%-100%). The emergence of lobar/sublobar consolidations with dynamic air bronchograms on the day of suspicion had specificity of 96% (95% CI, 81%-99%). Finally, the proposed algorithm had sensitivity of 63% (95% CI, 46%-77%) and specificity of 85% (95% CI, 67%-94%) for VAP.

CONCLUSIONS

The presence of sonographic consolidations was not accurate for VAP when patients with previous lung parenchyma commitment were included. However, serial LUS examinations detected the emergence of specific signs of VAP.

Effect of mild hypothermia on lung injury after cardiac arrest in swine based on lung ultrasound

BACKGROUND

Lung injury is common in post-cardiac arrest syndrome, and is associated with increased morbidity and mortality. The aim of this study was to evaluate the effect of mild hypothermia on lung injury after cardiac arrest in swine based on lung ultrasound.

METHODS

Twenty-three male domestic swine weighing 36 ± 2 kg were randomly assigned to three groups: therapeutic hypothermia (TH, n = 9), normothermia (NT, n = 9), and sham control (control, n = 5) groups. Sham animals only underwent surgical preparation. The animal model was established with 8 min of ventricular fibrillation followed by 5 min of cardiopulmonary resuscitation. Therapeutic hypothermia was induced and maintained until 24 h post-resuscitation in the TH group by surface blanket cooling, followed by rewarming at a rate of 1 °C/h for 5 h. The extravascular lung water index (ELWI), pulmonary vascular permeability index (PVPI), PO2/FiO2, and lung ultrasound score (LUS) were measured at baseline and at 1, 3, 6, 12, 24, and 30 h after resuscitation. After euthanizing the swine, their lung tissues were quickly obtained to evaluate inflammation.

RESULTS

After resuscitation, ELWI and PVPI in the NT group were higher, and PO2/FiO2 was lower, than in the sham group. However, those measures were significantly better in the TH group than the NT group. The LUS was higher in the NT group than in the sham group at 1, 3, 6, 12, 24, and 30 h after resuscitation. The LUS was significantly better in the TH group compared to the NT group. The lung tissue biopsy revealed that lung injury was more severe in the NT group than in the TH group. Increases in LUS were highly correlated with increases in ELWI (r = 0.613; p < 0.001) and PVPI (r = 0.683; p < 0.001), and decreases in PO2/FiO2 (r = - 0.468; p < 0.001).

CONCLUSIONS

Mild hypothermia protected against post-resuscitation lung injury in a swine model of cardiac arrest. Lung ultrasound was useful to dynamically evaluate the role of TH in lung protection.

Lung ultrasound to detect and monitor pulmonary congestion in patients with acute kidney injury in nephrology wards: a pilot study

INTRODUCTION

Lung congestion and frank pulmonary edema are established complications of acute kidney injury (AKI) and early detection and monitoring of lung congestion may be useful for the clinical management of AKI patients.

METHODS

We compared standardized clinical criteria (including lung crackles and peripheral edema grading) and simultaneous chest ultrasound (US) to detect lung congestion in a series of 39 inpatients with AKI.

RESULTS

At baseline, twelve patients (31%) were clinically euvolemic and twelve presented clear-cur cardiovascular congestion (31%) by clinical criteria. Fifteen patients (38%) were hypovolemic. The median number of US-B lines in patients with cardiovascular congestion was much higher (50, inter-quartile range 27-99) than in euvolemic (14, IQR 11-37) and hypovolemic patients (7, IQR 3-16, P < 0.001). Remarkably, a substantial proportion of asymptomatic euvolemic (66%) and hypovolemic (46%) patients had lung congestion of moderate to severe degree (> 15 US-B lines) by lung US. Crackles severity and the number of US-B lines over time were inter-related (Spearman's ρ = 0.38, P < 0.01) but the agreement (Cohen k statistics) between the two metrics was unsatisfactory. Forty-eight percent of patients had lung congestion of moderate to severe degree by lung US and this estimate by far exceeded that by clinical criteria (32%).

CONCLUSIONS

This pilot study shows that chest US has potential for the detection of lung congestion at a pre-clinical stage in AKI. The results of this pilot study form the basis for a clinical trial testing the usefulness of this technique for guiding lung congestion treatment in patients with AKI.

Case Report: Pulmonary hemorrhage as a rare cause of lung ultrasound A/B-profile

When using lung ultrasound to determine the cause of acute respiratory failure, the BLUE protocol is often used. In a 65-year old patient, an A/B-profile was found, suggesting pneumonia, following the flowchart of this protocol. In this case, however, pulmonary hemorrhage confirmed by bronchoscopy was the final diagnosis. This case report outlines the importance of understanding the limitations of the BLUE protocol and that lung ultrasound findings should always be used in the context of the patient’s history and physical exam. In addition, pulmonary hemorrhage should be considered in patients with no clinical signs of pneumonia and/or presence of risk factors for lung bleeding as a rare cause of lung ultrasound A/B-profile.

Thoracic ultrasonography: a narrative review

This narrative review focuses on thoracic ultrasonography (lung and pleural) with the aim of outlining its utility for the critical care clinician. The article summarizes the applications of thoracic ultrasonography for the evaluation and management of pneumothorax, pleural effusion, acute dyspnea, pulmonary edema, pulmonary embolism, pneumonia, interstitial processes, and the patient on mechanical ventilatory support. Mastery of lung and pleural ultrasonography allows the intensivist to rapidly diagnose and guide the management of a wide variety of disease processes that are common features of critical illness. Its ease of use, rapidity, repeatability, and reliability make thoracic ultrasonography the "go to" modality for imaging the lung and pleura in an efficient, cost effective, and safe manner, such that it can largely replace chest imaging in critical care practice. It is best used in conjunction with other components of critical care ultrasonography to yield a comprehensive evaluation of the critically ill patient at point of care.

Correlation between Transthoracic Lung Ultrasound Score and HRCT Features in Patients with Interstitial Lung Diseases

Chest high-resolution computed tomography (HRCT) is considered the “gold” standard radiological method in interstitial lung disease (ILD) patients. The objectives of our study were to evaluate the correlation between two transthoracic lung ultrasound (LUS) scores (total number of B-lines score = the total sum of B-lines in 10 predefined scanning sites and total number of positive chest areas score = intercostal spaces with ≥3 B-lines) and the features in HRCT simplified scores, in different interstitial disorders, between LUS scores and symptoms, as well as between LUS scores and pulmonary function impairment. We have evaluated 58 consecutive patients diagnosed with ILD. We demonstrated that there was a good correlation between the total number of B-lines score and the HRCT simplified score (r = 0.784, p < 0.001), and also a good correlation between the total number of positive chest areas score and the HRCT score (r = 0.805, p < 0.005). The results confirmed the value of using LUS as a diagnostic tool for the assessment of ILD compared to HRCT. The use of LUS in ILD patients can be a useful, cheap, accessible and radiation-free investigation and can play a complementary role in the diagnosis and monitoring of these patients.