INTRODUCTION AND STUDY AIM
In the last years, Lung Ultrasound (LUS) has gained a primary role in the diagnosis and management of pleuropulmonary disorders, also in pediatric practice.1-3
LUS is a non-invasive, non-ionizing radiation tool and a rapid, affordable, point-of-care imaging modality that allow both real-time diagnosis and follow-up of respiratory diseases.1-3LUS results are immediately available to the clinician, especially in emergency conditions who can therefore immediately orient himself towards a diagnosis so that a quick therapeutic decision can be made.
Several studies performed in the pediatric population have shown that LUS may be better than chest radiography in the diagnosis of community-acquired pneumonia1-3, can define the etiology of pneumonia3,4 and many studies have described and validated LUS pattern or score (based mainly on vertical artifacts and subpleural consolidations) in neonatal respiratory disorders5 and bronchiolitis6 but also the normal LUS pattern in healthy infants. 2
The latter and other categories of patients are united by having in common the presence of sonographic interstitial syndrome (SIS): the presence of multiple or focal, patched or diffuse vertical artifacts (B-lines) fanning out from the lung wall interface. 7 It is in fact a lung ultrasound picture common to various respiratory diseases. 2,6,8
However, to define the nature and possible origin of SIS, not having many pediatric studies on interpretation of LUS vertical artifacts available, especially as regards the differentiation between cardiogenic pulmonary edema or no inflammatory pulmonary congestion and pulmonary edema of inflammatory origin or fibrosis, up to now it was necessary to refer to the studies performed on adults, having always in mind the knowledge of the patient’s clinical background.7-10
In particular, according to studies performed on physical models and in adult patients7-10, the B lines or vertical artifacts, in the absence of an analysis of their appearance, cannot easily differentiate the cause. Soldati et al.7,8,10 have shown that the B lines are heterogeneous entities in terms of aggregation and visual structure, the nature of which is linked to the superficial histological characteristics of their wavelength. Vertical artifacts generated by a fibrotic or inflammatory lung have a different appearance from those generated by cardiogenic edema.
Furthermore, several studies performed on the adult population11-13 have shown that LUS now plays a leading role in the work-up of adult patients with suspected cardiogenic pulmonary edema. In fact, the approach that has the best performance is the one that combines chest X-ray and the determination of the pro-BNP level with the early use of LUS.13 Recent studies and systemic reviews11,12 have shown that LUS is highly sensitive and specific (with a greater sensitivity and specificity than chest x-ray) in early identification of cardiogenic pulmonary edema and in its differentiation from primary pulmonary pathologies in dyspneic geriatric patients (through the evaluation of the B lines). 7-13
In addition, other studies have shown that the level of pro-BNP is not only related to pulmonary edema from heart failure.15-17 In fact, the increase in the value of NT-pro-BNP, with consequent different degree of pulmonary congestion, may also be present in the course of other diseases such as the systemic inflammatory syndrome and / or sepsis also in the absence of organic or functional damage to the myocardium.16,17
In the pediatric population, on the other hand, in order to interpret the nature of the SIS picture caused by cardio-pulmonary interactions and not by primary pulmonary pathologies, up to now we have referred to the aforementioned preclinical and clinical studies performed on the adult population. 7-13 In particular, in the pediatric population a study has never yet been performed which aims to define the lung ultrasound pattern in acutely ill children (with heart disease and / or with systemic inflammatory syndrome or sepsis) with a high pro-BNP level.
Starting from all these assumptions we performed this prospective observational study aiming to define the LUS pattern in these categories of acutely ill pediatric patients without primary lung diseases and with high pro-BNP level.