Lung ultrasound: are we diagnosing too much?

The clinical use of lung ultrasound (LUS) has made more efficient many diagnostic processes at bedside. The great power of LUS is a superior diagnostic sensitivity in many applications, when compared to chest radiography (CXR). The implementation of LUS in emergency is contributing to reveal a growing number of radio-occult pulmonary conditions. In some diseases, the superior sensitivity of LUS is a great advantage, like for pneumothorax and pulmonary edema. Diagnosing at bedside pneumothoraxes, pulmonary congestions, and COVID-19 pneumonia that are visible by LUS but undetected by CXR may be decisive for appropriate management, and even for saving lives. However, in other conditions, like bacterial pneumonia and small peripheral infarctions due to subsegmental pulmonary embolism, the high sensitivity of LUS does not always lead to advantages. Indeed, we doubt that it is always necessary to treat by antibiotics patients suspected of lower respiratory tract infection, who show radio-occult pulmonary consolidations, and to treat by anticoagulation patients with small subsegmental pulmonary embolism. The possibility that we are overtreating radio-occult conditions should be investigated with dedicated clinical trials.

Feasibility of a New Lung Ultrasound Protocol to Determine the Extent of Lung Injury in COVID-19 Pneumonia.

BACKGROUND: Lung ultrasound (LUS) scanning is useful to diagnose and assess the severity of pulmonary lesions during COVID-19-related ARDS (CoARDS). A conventional LUS score is proposed to measure the loss of aeration during CoARDS. However, this score was validated during the pre-COVID-19 era in patients with ARDS in the ICU and does not consider the differences with CoARDS. An alternative LUS method is based on grading the percentage of extension of the typical signs of COVID-19 pneumonia on the lung surface (LUSext). RESEARCH QUESTION: Is LUSext feasible in patients with COVID-19 at the onset of disease, and does it correlate with the volumetric measure of severity of COVID-19 pneumonia lesions at CT scan (CTvol)? STUDY DESIGN AND METHODS: This observational study enrolled a convenience sampling of patients in the ED with confirmed COVID-19 whose condition demonstrated pneumonia at bedside LUS and CT scan. LUSext was visually quantified. All CT scan studies were analyzed retrospectively by a specifically designed software to calculate the CTvol. The correlation between LUSext and CTvol, and the correlations of each score with Pao2/Fio2 ratio were calculated. RESULTS: We analyzed data from 179 patients. Feasibility of LUSext was 100%. Time to perform LUS scan was 5 ± 1.5 mins. LUSext and CTvol were correlated positively (R = 0.67; P < .0001). Both LUSext and CTvol showed negative correlation with Pao2/Fio2 ratio (R = -0.66 and R = -0.54; P < .0001, respectively). INTERPRETATION: LUSext is a valid measure of the severity of the lesions when compared with the CT scan. Not only are LUSext and CTvol correlated, but they also have similar inverse correlation with the severity of respiratory failure. LUSext is a practical and simple bedside measure of the severity of pneumonia in CoARDS, whose clinical and prognostic impact need to be investigated further.

Retrospective analysis of the application of CT scan in the emergency department to screen clinically asymptomatic COVID-19 before hospital admission.

BACKGROUND: The necessity to identify and isolate COVID-19 patients to avoid intrahospital cross infections is particularly felt as a challenge. Clinically occult SARS-CoV-2 infection among patients admitted to the hospital is always considered a risk during the pandemic. The aim of our study is to describe the application of CT scan to reveal unexpected COVID-19 in patients needing hospital admission. METHOD: In our emergency department, we prospectively enrolled adult patients needing hospital admission, without symptoms suspected of COVID-19, and showing negative reverse transcriptase-polymerase chain reaction (RT-PCR) swab test. CT scan was performed to diagnose clinically occult COVID-19 pneumonia. All the exams were read and discussed retrospectively by two expert radiologists and assigned to one of 4 exclusive diagnoses: typical (typCT), indeterminate (indCT), atypical (atyCT), negative (negCT). The clinical characteristics and final diagnoses were described and compared with the results of CT scans. RESULTS: From May 25 to August 18, 2020, we prospectively enrolled 197 patients. They showed 122 negCT, 52 atyCT, 22 indCT, and 1 typCT. Based on the CT imaging, the prevalence of suspected clinically occult COVID-19 pneumonia was 11.6% (23 patients). None had confirmation of SARS-CoV-2 infection after the hospital stay. Nineteen patients had negative serial RT-PCR while in 4 cases, the infection was excluded by clinical follow-up or appearance of positivity of RT-PCR after months. CONCLUSION: Our descriptive analysis confirms that CT scan cannot be considered a valid tool to screen clinically occult COVID-19, when the asymptomatic patients need hospitalization for other conditions. Application of personnel protections and distancing among patients remains the best strategies to limit the possibility of intrahospital cross-infections.

Are Lung Ultrasound Findings in COVID-19 Pneumonia Typical or Specific?

The application of point-of-care lung ultrasound (LUS) in the first diagnosis and management of Corona Virus Disease 2019 (COVID-19) has gained a great interest during a pandemic that is undermining even the most advanced health systems. LUS demonstrated high sensitivity in the visualization of the interstitial signs of the typical pneumonia complicating the infection. However, although this disease gives typical lung alterations, the same LUS signs observed in COVID-19 pneumonia can be detected in other common pulmonary conditions. While being non-specific when considered separately, the analysis of the distribution of the sonographic typical signs allows the assignment of 4 LUS patterns of probability for COVID-19 pneumonia when the whole chest is examined and attention is paid to the presence of other atypical signs. Moreover, the combination of LUS likelihood with the clinical phenotype at presentation increases the accuracy. This mini-review will analyze the LUS signs of COVID-19 pneumonia and how they can be combined in patterns of probability in the first approach to suspected cases.

Lung ultrasound for the early diagnosis of COVID-19 pneumonia: an international multicenter study.

PURPOSE: To analyze the application of a lung ultrasound (LUS)-based diagnostic approach to patients suspected of COVID-19, combining the LUS likelihood of COVID-19 pneumonia with patient's symptoms and clinical history. METHODS: This is an international multicenter observational study in 20 US and European hospitals. Patients suspected of COVID-19 were tested with reverse transcription-polymerase chain reaction (RT-PCR) swab test and had an LUS examination. We identified three clinical phenotypes based on pre-existing chronic diseases (mixed phenotype), and on the presence (severe phenotype) or absence (mild phenotype) of signs and/or symptoms of respiratory failure at presentation. We defined the LUS likelihood of COVID-19 pneumonia according to four different patterns: high (HighLUS), intermediate (IntLUS), alternative (AltLUS), and low (LowLUS) probability. The combination of patterns and phenotypes with RT-PCR results was described and analyzed. RESULTS: We studied 1462 patients, classified in mild (n = 400), severe (n = 727), and mixed (n = 335) phenotypes. HighLUS and IntLUS showed an overall sensitivity of 90.2% (95% CI 88.23-91.97%) in identifying patients with positive RT-PCR, with higher values in the mixed (94.7%) and severe phenotype (97.1%), and even higher in those patients with objective respiratory failure (99.3%). The HighLUS showed a specificity of 88.8% (CI 85.55-91.65%) that was higher in the mild phenotype (94.4%; CI 90.0-97.0%). At multivariate analysis, the HighLUS was a strong independent predictor of RT-PCR positivity (odds ratio 4.2, confidence interval 2.6-6.7, p < 0.0001). CONCLUSION: Combining LUS patterns of probability with clinical phenotypes at presentation can rapidly identify those patients with or without COVID-19 pneumonia at bedside. This approach could support and expedite patients' management during a pandemic surge.

Lung Ultrasound Scanning for Respiratory Failure in Acutely Ill Patients: A Review.

Lung ultrasonography (LUS), an imaging modality quickly performed, interpreted, and integrated by the treating physician at the bedside, is a particularly useful tool for acutely ill patients. In the evaluation of a patient with respiratory failure in the ICU or ED, LUS is superior to chest radiograph and generally comparable with CT imaging and reduces the need for patient transport and radiation exposure. This article will provide a concise review of LUS as it pertains to respiratory failure in general and will include examples of relevant ultrasound images and video clips from critically ill patients.

Descriptive analysis of a comparison between lung ultrasound and chest radiography in patients suspected of COVID-19.

BACKGROUND: Lung ultrasound (LUS) and chest radiography (CXR) are the most used chest imaging tools in the early diagnosis of COVID-19 associated pneumonia. However, the relationship between LUS and CXR is not clearly defined. The aim of our study was to describe the comparison between LUS interpretation and CXR readings in the first approach to patients suspected of COVID-19. METHODS: In the time of the first COVID-19 pandemic surge, we prospectively evaluated adult patients presenting to an emergency department complaining of symptoms raising suspicion of COVID-19. Patients were studied by LUS and only those performing also CXR were analyzed. All the patients performed viral reverse transcriptase-polymerase chain reaction (RT-PCR). LUS studies were classified in 4 categories of probabilities, based on the presence of typical or alternative signs of COVID-19-associated interstitial pneumonia. Accordingly, the CXR readings were retrospectively adapted by 2 experts in 4 categories following the standard language that describes the computed tomography (CT) findings. Patients were divided in two groups, based on the agreement of the LUS and CXR categories. Results were also compared to RT-PCR and, when available, to CT studies. RESULTS: We analyzed 139 cases (55 women, mean age 59.1 ± 15.5 years old). The LUS vs CXR results disagreed in 60 (43.2%) cases. RT-PCR was positive in 88 (63.3%) cases. In 45 cases, a CT scan was also performed and only 4 disagreed with LUS interpretation versus 24 in the comparison between CT and CXR. In 18 cases, LUS detected signs of COVID-19 pneumonia (high and intermediate probabilities) while CXR reading was negative; in 14 of these cases, a CT scan or a RT-PCR-positive result confirmed the LUS interpretation. In 6 cases, LUS detected signs of alternative diagnoses to COVID-19 pneumonia while CXR was negative; in 4 of these cases, CT scan confirmed atypical findings. CONCLUSION: Our study demonstrated a strong disagreement between LUS interpretation and CXR reading in the early approach to patients suspected of COVID-19. Comparison with CT studies and RT-PCR results seems to confirm the superiority of LUS over a second retrospective reading of CXR.

Patients in intensive care unit for COVID-19 pneumonia: the lung ultrasound patterns at admission and discharge. An observational pilot study.

BACKGROUND: During COVID-19 pandemic, optimization of the diagnostic resources is essential. Lung Ultrasound (LUS) is a rapid, easy-to-perform, low cost tool which allows bedside investigation of patients with COVID-19 pneumonia. We aimed to investigate the typical ultrasound patterns of COVID-19 pneumonia and their evolution at different stages of the disease. METHODS: We performed LUS in twenty-eight consecutive COVID-19 patients at both admission to and discharge from one of the Padua University Hospital Intensive Care Units (ICU). LUS was performed using a low frequency probe on six different areas per each hemithorax. A specific pattern for each area was assigned, depending on the prevalence of A-lines (A), non-coalescent B-lines (B1), coalescent B-lines (B2), consolidations (C). A LUS score (LUSS) was calculated after assigning to each area a defined pattern. RESULTS: Out of 28 patients, 18 survived, were stabilized and then referred to other units. The prevalence of C pattern was 58.9% on admission and 61.3% at discharge. Type B2 (19.3%) and B1 (6.5%) patterns were found in 25.8% of the videos recorded on admission and 27.1% (17.3% B2; 9.8% B1) on discharge. The A pattern was prevalent in the anterosuperior regions and was present in 15.2% of videos on admission and 11.6% at discharge. The median LUSS on admission was 27.5 [21-32.25], while on discharge was 31 [17.5-32.75] and 30.5 [27-32.75] in respectively survived and non-survived patients. On admission the median LUSS was equally distributed on the right hemithorax (13; 10.75-16) and the left hemithorax (15; 10.75-17). CONCLUSIONS: LUS collected in COVID-19 patients with acute respiratory failure at ICU admission and discharge appears to be characterized by predominantly lateral and posterior non-translobar C pattern and B2 pattern. The calculated LUSS remained elevated at discharge without significant difference from admission in both groups of survived and non-survived patients.

Lung Ultrasound for Patients With Coronavirus Disease 2019 Pulmonary Disease.

Given the general utility of lung ultrasound for the evaluation of respiratory failure in acutely ill patients, it is logical to consider its specific advantages in coronavirus disease 2019-related pulmonary disease. The authors, representing the extensive experience of the North American and European coronavirus disease 2019 epicenters, present an ultrasound scanning protocol and report on the common associated ultrasound findings.

The Potential for Remotely Mentored Patient-Performed Home Self-Monitoring for New Onset Alveolar-Interstitial Lung Disease.

Purpose: Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is an acute respiratory illness. Although most infected persons are asymptomatic or have only mild symptoms, some patients progress to devastating disease; such progression is difficult to predict or identify in a timely manner. COVID-19 patients who do not require hospitalization can self-isolate at home. Calls from one disease epicenter identify the need for homebased isolation with telemedicine surveillance to monitor for impending deterioration. Methodology: Although the dominant approach for these asymptomatic/paucisymptomatic patients is to monitor oxygen saturation, we suggest additionally considering the potential merits and utility of home-based imaging. Chest computed tomography is clearly impractical, but ultrasound has shown comparable sensitivity for lung involvement, with major advantages of short and simple procedures, low cost, and excellent repeatability. Thoracic ultrasound may thus allow remotely identifying the development of pneumonitis at an early stage of illness and potentially averting the risk of insidious deterioration to severe pneumonia and critical illness while in home isolation. Conclusions: Lung sonography can be easily performed by motivated nonmedical caregivers when directed and supervised in real time by experts. Remote mentors could thus efficiently monitor, counsel, and triage multiple home-based patients from their "control center." Authors believe that this approach deserves further attention and study to reduce delays and failures in timely hospitalization of home-isolated patients.

Sonographic signs and patterns of COVID-19 pneumonia.

The pandemic of COVID-19 is seriously challenging the medical organization in many parts of the world. This novel corona virus SARS-CoV-2 has a specific tropism for the low respiratory airways, but causes severe pneumonia in a low percentage of patients. However, the rapid spread of the infection during this pandemic is causing the need to hospitalize a high number of patients. Pneumonia in COVID-19 has peculiar features and can be studied by lung ultrasound in the early approach to suspected patients. The sonographic signs are non-specific when considered alone, but observation of some aspects of vertical artifacts can enhance the diagnostic power of the ultrasound examination. Also, the combination of sonographic signs in patterns and their correlation with blood exams in different phenotypes of the disease may allow for a reliable characterization and be of help in triaging and admitting patients.