Lung Ultrasound Is Often, but Not Always, Normal in Healthy Subjects: Considerations for COVID-19 Pandemic

Lung Ultrasound Abnormalities in Patients Without Pulmonary Pathology Prior to Surgery

Background

The occurrence of lung ultrasound abnormalities in patients without lung disease remains uncertain, while patients with respiratory disease often exhibit such abnormalities.

Objectives

The primary aim was to identify pathological ultrasonographic pulmonary findings and their correlation with baseline diseases and static lung compliance in patients without any pre-existing respiratory conditions.

Methods

This prospective observational study enrolled a series of surgical patients with no history of pulmonary pathology (n = 104). Baseline diseases and patients' physical status classification, based on the American Society of Anesthesiologists (ASA), were documented by reviewing medical records. Prior to surgery, a lung ultrasound was performed to assess pulmonary changes. During surgery with general anesthesia, static lung compliance was measured. The Spearman correlation coefficient was employed to determine the correlation between the two variables.

Results

Twenty-four patients (23.07%) exhibited 1 - 2 B-lines in certain lung fields. Seven patients (6.7%) had an ultrasound B-line score > 0 (indicating ≥ 3 B-lines). Among these patients, the average number of lung fields with ≥ 3 B-lines was 3.71 ± 2.43. Patients with systemic diseases (ASA ≥ 2) displayed a higher number of B-lines compared to ASA I patients (P-value = 0.039). Pleural irregularities were found in 10 patients (9.6%), while atelectasis and pleural effusion were observed in five (4.8%) and four (3.8%) patients, respectively. The mean lung compliance value was 56.78 ± 15.33. No correlation was observed between the total score of the B-lines and lung compliance (Spearman's correlation: rho = -0.028, P-value = 0.812).

Conclusions

Patients without pulmonary pathology may exhibit ultrasound pulmonary abnormalities, which tend to increase with higher ASA scores and do not appear to have a correlation with static lung compliance.

Lung ultrasound as a screening tool for SARS-CoV-2 infection in surgical patients

PURPOSE

To evaluate the diagnostic performance of lung ultrasound (LUS) in screening for SARS-CoV-2 infection in patients requiring surgery.

METHODS

Patients underwent a LUS protocol that included a scoring system for screening COVID-19 pneumonia as well as RT-PCR test for SARS-CoV-2. The receiver operator characteristic (ROC) curve was determined for the relationship between LUS score and PCR test results for COVID-19. The optimal threshold for the best discrimination between non-COVID-19 patients and COVID-19 patients was calculated.

RESULTS

Among 203 patients enrolled (mean age 48 years; 82 males), 8.3% were COVID-19-positive; 4.9% were diagnosed via the initial RT-PCR test. Of the patients diagnosed with SARS-CoV-2, 64.7% required in-hospital management and 17.6% died. The most common ultrasound findings were B lines (19.7%) and a thickened pleura (19.2%). The AUC of the ROC curve of the relationship of LUS score with a cutoff value >8 versus RT-PCR test for the assessment of SARS-CoV-2 pneumonia was 0.75 (95% CI 0.61-0.89; sensitivity 52.9%; specificity 91%; LR (+) 6.15, LR (-) 0.51).

CONCLUSION

The LUS score in surgical patients is not a useful tool for screening patients with potential COVID-19 infection. LUS score shows a high specificity with a cut-off value of 8.

Efficacy of a short course of lung ultrasound for primary care physicians in the assessment of COVID-19-positive patients

INTRODUCTION

Lung ultrasound (LUS) has become the first diagnostic imaging approach to assess lung involvement in COVID-19. While LUS proved to be safe, reliable, and accurate, not many primary care physicians (PCP) are capable to employ this instrument in the first evaluation of COVID-19 outpatients. The aim of this study was to determine the effectiveness of a brief training program in LUS for PCP.

METHODS

Italian local authorities promoted a training program in LUS for PCP engaged in COVID-19 outpatients' evaluation. The course took place in a COVID-19 unit and included a hands-on practice on real COVID-19 patients. We conducted a qualitative and quantitative analysis of the results of the training program.

RESULTS

A total of 32 PCP completed the training. About 100% of participants reported an increase in competence and confidence in the use of LUS after the training. Self-reported confidence in detecting major COVID-19 LUS abnormalities was high (B-lines 8/10, pleural abnormalities 6.5/10). B-lines were accurately identified with a reliability of 81%, with a sensitivity of 96%, and a negative predictive value of 98%. Trainees were some less accurate in detecting pleural abnormalities (reliability 63%) but with a high specificity (99%).

CONCLUSIONS

This study showed that a short training program, but comprising a hands-on practice, is capable to bring even almost novices to achieve a high overall accuracy and reliability in detecting lung involvement in COVID-19. This may result in a significant improvement of the performances of PCP involved in the first evaluation of COVID-19 cases in primary care facilities.

Pulmonary Function and Psychological Burden Three Months after COVID-19: Proposal of a Comprehensive Multidimensional Assessment Protocol

Persisting limitations in respiratory function and gas exchange, cognitive impairment, and mental health deterioration have been observed weeks and months after acute SARS-CoV-2 (COVID-19). The present study aims at assessing the impairment at three-months in patients who successfully recovered from acute COVID-19. We collected data from May to July 2020. Patients underwent a multidimensional extensive assessment including pulmonary function test, psychological tests, thoracic echo scan, and functional exercise capacity. A total of 21 patients (M:13; Age 57.05 ± 11.02) completed the global assessment. A considerable proportion of patients showed symptoms of post-traumatic stress disorder (28.6%), moderate depressive symptoms (9.5%), and clinical insomnia (9.5%); 14.3% of patients exhibited moderate anxiety. A total of eleven patients (52.4%) showed impaired respiratory gas exchange capacity (P-DLCO, DLCO ≤ 79% pred). Compared to patients with normal gas exchange, the P-DLCO subgroup perceived a significant worsening in quality of life (QoL) after COVID-19 (p = 0.024), higher fatigue (p = 0.005), and higher impact of lung disease (p = 0.013). In P-DLCO subgroup, higher echo score was positively associated with hospitalization length of stay (p = 0.047), depressive symptoms (p = 0.042), fatigue (p = 0.035), impairment in mental health (p = 0.035), and impact of lung disease in health status (p = 0.020). Pulmonary function and echo scan lung changes were associated to worsened QoL, fatigue, and psychological distress symptoms.

Lung Ultrasound: A Diagnostic Leading Tool for SARS-CoV-2 Pneumonia: A Narrative Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide causing a global pandemic. In this context, lung ultrasound (LUS) has played an important role due to its high diagnostic sensitivity, low costs, simplicity of execution and radiation safeness. Despite computed tomography (CT) being the imaging gold standard, lung ultrasound point of care exam is essential in every situation where CT is not readily available nor applicable. The aim of our review is to highlight the considerable versatility of LUS in diagnosis, framing the therapeutic route and follow-up for SARS-CoV-2 interstitial syndrome.