The significance of bedside lung ultrasound on predicting COVID-19-related hospitalization in children

A recent study posted to the medRxiv* preprint server demonstrated the significance of bedside lung ultrasound on predicting coronavirus disease 2019 (COVID-19)-related hospitalization in children. 

Background

Near-patient lung ultrasound enables the early diagnosis of viral pneumonitis in children with a viral respiratory infection. Lung ultrasound has been validated to predict the diagnosis of COVID-19-associated pneumonitis employing a computed tomography (CT) gold standard in older children and adults. Lung ultrasound also foretells those with higher chances of disease progression. 

In contrast to other viral pneumonitis, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces hyperferritinemia and elevated levels of inflammatory markers such as D-dimer, transaminases, lactate dehydrogenase (LDH), C-reactive protein (CRP), and troponin. While point-of-care lung ultrasound is minimally invasive and quick, blood tests are associated with more staff time and worry for both parents and children. However, the correlations between lung ultrasound and COVID-19-linked hospitalization and the requirements for lung ultrasound results to avoid blood work in SARS-CoV-2-infected children remain unknown.

About the study

In the current study, the researchers investigated whether 1) the SARS-CoV-2-related hospitalization was linked to the degree of pneumonitis seen on lung ultrasound and 2) lung ultrasound can be used to determine which children require blood work.

The team performed a retrospective cross-sectional analysis of children aged 14 days to 21 years. The study population was treated for SARS-CoV-2 infection in the Sutter Medical Center Sacramento's pediatric emergency department (ED) from November 30, 2019, to August 14, 2021. The included subjects also had a bedside lung ultrasound at the ED.

A six-point ordinal scale was used to classify lung ultrasounds. The adjusted impact of lung ultrasound on COVID-19-linked hospitalization was computed using logistic regression. The relationship between lung ultrasound severity and abnormalities in laboratory findings was studied using ordinary least square analysis. The team adjusted the ordinary least square regression via propensity score-based inverse probability weighting to address the non-random decision to conduct laboratory investigations.

Findings

The results demonstrated that of the 500 point-of-care lung ultrasounds identified, 427 could be classified based on severity. Increased severity of lung ultrasound was linked with elevated SARS-CoV-2-related hospitalization.

Lung ultrasound with more than moderate severity was linked to a hike in transaminases, D-dimer, LDH, and ferritin levels. By contrast, normal lung ultrasound was inadequate to determine the necessity of troponin, erythrocyte sedimentation rate (ESR), pro-B type natriuretic peptide (Pro-BNP), procalcitonin, or CRP evaluations in children. This was because troponin, D-dimer, and CRP levels were occasionally high even when the lung ultrasound was normal. As a result, although more than moderate pneumonitis on lung ultrasound should trigger blood testing, normal or less severe lung ultrasound results do not negate the necessity for blood tests in children.

In children, the SARS-CoV-2 non-Omicron strains result in hospital admission for reasons additional to isolated lung injury. As a result, management modalities for SARS-CoV-2 non-Omicron variants should treat COVID-19 as having coinciding hematological, pulmonary, immunological, clotting, cardiac, and gastrointestinal components, each of which has the potential to cause morbidity.

Troponin increases over the 99th centile were seen in 9/48 COVID-19 patients, and they had no association to lung ultrasound severity. The onset of chest ache in verbal and irritability in preverbal children, and lung ultrasound, or clinical respiratory symptoms appear to influence the choice to conduct troponin testing, albeit this was not officially quantified in the current research. This suggests that troponin testing should be performed in an irritable newborn with COVID-19, even in the absence of pulmonary disease.

Conclusions

The study findings indicated that the severity of pneumonitis in the bedside lung ultrasound at the ED was linked with high rates of SARS-CoV-2-related hospitalization in children. These findings contribute to the credibility of lung ultrasound as a therapeutically valuable technology. Nevertheless, lung ultrasound results were just part of the pathology resulting in hospital admission in SARS-CoV-2 non-Omicron waves. In addition, lung ultrasound-detected lung injury alone did not account for all hospitalizations in the current study.

Elevations in D-dimer, LDH, ferritin, and transaminase levels were observed during pneumonitis with more than moderate severity. Yet, lung ultrasound did not foresee the rise of other inflammatory markers.

Overall, the present work suggests that if a child has pneumonitis with more than moderate severity on lung ultrasound, blood tests for ferritin and other indicators of severe disease are warranted. For less severe lung ultrasound anomalies, additional clinical indicators such as chest discomfort or irritability determine if laboratory testing is necessary.

Moreover, in these situations, testing should target troponin and inflammatory indicators. D-dimer levels indicate both peripheral and pulmonary clotting. Nonetheless, the choice to test D-dimer will depend upon the mindset of the doctors on treating evident pulmonary and disseminated hypercoagulable disorders in children.

*Important notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Written by

Shanet Susan Alex

Shanet Susan Alex, a medical writer, based in Kerala, India, is a Doctor of Pharmacy graduate from Kerala University of Health Sciences. Her academic background is in clinical pharmacy and research, and she is passionate about medical writing. Shanet has published papers in the International Journal of Medical Science and Current Research (IJMSCR), the International Journal of Pharmacy (IJP), and the International Journal of Medical Science and Applied Research (IJMSAR). Apart from work, she enjoys listening to music and watching movies.