The Lung Ultrasound Score Cannot Accurately Evaluate the Severity of Neonatal Lung Disease

Abstract

F or nearly a decade, lung ultrasound (LUS) has been extensively used in the diagnosis and differential diagnosis of neonatal lung diseases because of its increased accuracy and effectiveness compared with traditional chest radiography, and LUS has replaced radiography in the diagnosis of neonatal lung diseases in some neonatal intensive care units.However, during the development of LUS, it was expected that LUS could quantitatively evaluate the severity of lung diseases, with a so-called LUS scoring system. On the basis of my accumulated experiencewithmore than10 years of research in this field, I found that the LUS score not only cannot be used to accurately assess the severity of neonatal lung disease but also may result in substantial discrepancies. The LUS score has the following major defects and shortcomings: 1. A score of 1 is assigned for pulmonary interstitial syndrome according to the presence of “multiple isolated B-lines”. However, the term “multiple B-lines” is not clearly defined in the scoring system. For instance, the LUS score would be 1 according to the system, regardless of the presence of 3 or 4 B-lines or more than 10 B-lines. This scoring criterion is obviously inappropriate because the number of B-lines is associated with the severity of edema. 2. A score of 1 is assigned for focal lung edema, and a score of 2 is assigned for alveolar edema. For focal lung edema, coalescent B-lines should occupy less than 50% of the intercostal space in the whole lung field. However, for alveolar edema, coalescent B-lines should occupy 100% of the intercostal space in the whole lung field. The question is how the edema should be scored when coalescent B-lines occupy between 50% and 100% of the intercostal space in the field, which is a very common condition in clinical practice. 3. The system ignores the influence of the distribution zones of coalescent B-lines. Lung US commonly displays different patterns of coalescent B-lines in different lung zones. Coalescent B-lines are present in some intercostal spaces, whereas other spaces may be normal or abnormal, reflecting different degrees of Manuscript accepted for publication September 10, 2019. This work was supported by the Social Development Projects, Beijing Chaoyang District Bureau of Science, Technology, and Information (grant CYSF1922). Address correspondence to Jing Liu, MD, PhD, Department of Neonatology and Neonatal Intensive Care Unit, Beijing Chaoyang District Maternal and Child Healthcare Hospital, 25 Huaweili, Panjiayuan Chaoyang District, 100101 Beijing, China. E-mail: [email protected]