Bedside lung ultrasonography helps to obtain reliable clinical information about lung aeration, that has been categorized by means of the so-called lung ultrasound score (LUS). In critically ill adults, LUS has been related with the outcome both in patients with respiratory and some non-respiratory conditions. Pediatric studies about lung aeration have been done mainly on postoperative cardiac patients and infants with bronchiolitis. In this prospective, observational, multicenter, feasibility and diagnostic accuracy study, we will explore the degree of lung aeration impairment as a potential outcome predictor in critically ill children with a variety of underlying conditions. Children from 1 month to 18 years of age admitted to PICU will be recruited and LUS will be calculated at two time points: at 12 ± 6 hours and at 48-72 hours. Univariate and multivariate statistical analysis will be performed in order to ascertain the outcome influence of clinical factors in general and LUS in particular.

Lung aeration can be assessed at the bedside by means of lung ultrasound, a non-invasive, quick, simple, and reproducible technique. It provides semiquantitative information about the amount of extravascular lung water (EVLW), which correlates with lung aeration. Accumulation of EVLW occurs secondarily to acute lung injury due to infection, inflammation or fluid overload. Lung aeration, measured by the lung ultrasound score (LUS), has been associated to patients' outcome in several studies in adult patients, suggesting that critically ill subjects showing higher degree of aeration loss have a worse outcome. This fact has been shown not only in patients with baseline respiratory conditions (for example in severe acute respiratory syndrome coronavirus 2), but also in adults with non-respiratory conditions, such as shock and in high-risk postoperative patients. Furthermore, animal studies have suggested that information obtained through lung ultrasonography may precede clinical signs and could help anticipate focused treatment.

To date, pediatric studies addressing the potential relationship between LUS and the outcome of critically ill children are scarce and limited to postoperative cardiac patients and infants with bronchiolitis.

In our research, children from 1 month to 18 years of age admitted to pediatric intensive care unit (PICU) who fulfill inclusion criteria will be recruited and will undergo point of care lung ultrasound examination at 12 ± 6 hours and at 48-72 hours from admission. Clinical data will be recorded and LUS will be calculated. The main objective of our study is to assess the potential role of LUS (as a semiquantitative indicator or lung aeration) as a feasible and reliable outcome prediction tool in children admitted to PICU. Secondary objectives will include to analyze the correlations between LUS and the need and length of ventilatory support, inflammatory and cardiac markers, hydric balance, renal replacement therapies requirement, and validated prognostic scales, as well as age, underlying disease, co-morbidities, length-of-stay, and other clinical characteristics of included children.

Patients with acute respiratory distress syndrome (ARDS) or shock during PICU admission time will also undergo additional lung ultrasound examinations at 12 ± 6 hours and at 48-72 hours from ARDS or shock diagnosis, as these subgroups represent a very specific and severe cohort of patients, which merits further analysis.

Inclusion Criteria:

• Children 1 month to 18 years-old admitted to PICU due to an acute condition

Exclusion Criteria:

1. - Children admitted to PICU to perform a procedure or to adjust a certain treatment (eg, home ventilatory support).
2. - Children with chronic pulmonary pathology (cystic fibrosis, bronchopulmonary dysplasia, etc…)
3. - Preoperative admissions in a stable condition (eg. Patient admitted previously to cardiac surgery)
4. - Inability to obtain interpretable ultrasonographic images due to bad ultrasonographic window
5. - Non disponibility of investigator
6. - High frequency ventilation
7. - Lack of clinical data

Children 1 month to 18 years-old admitted to PICU due to an acute condition