(680) Lung Ultrasound Score Is Associated With Severity of Respiratory Disease in Critically Ill Children

Introduction: Lung ultrasound (LUS) is a useful tool for diagnosing and assessing the disease severity of pediatric respiratory illness, however, its role in the pediatric ARDS is ill-defined. We hypothesize that LUS score will be higher among children with ARDS compared to those with less severe lung disease within 48 hours of respiratory failure.

Methods: Prospective, two-center study of children admitted to PICU with acute respiratory failure requiring respiratory support. Patients were stratified into 3 groups by diagnosis: 1) pediatric ARDS, 2) lower respiratory tract infection (LRTI) and 3) respiratory failure due to non-respiratory cause (control). A single sonographer performed a protocolized 12-region LUS study at 0-24 hours of respiratory failure (Time 1) and a second LUS between 24-48 hours (Time 2) for patients with ARDS and LRTI. Raters blinded to the clinical information scored LUS images between 0 to 3 (0= normal, 3 = least aerated) for each region (max score = 36). Statistic comparison utilized Kruskal-Wallis test, Dunn test or Chi-square test. A p-value < 0.05 inferred statistical significance and continuous values appear as median (IQR).

Results: 60 children (ARDS: n=16, LRTI: n=25, control: n=21) were included; median age was 1.6 (0.5, 6.0) year. At time 1 LUS, all children with ARDS were on conventional mechanical ventilation with a median oxygen saturation index of 7.2 (6.4, 9.8). Children with LRTI were on HFNC (n=3), CPAP (n=6), BiPAP (n=12) and conventional mechanical ventilation (n=5). The majority of controls (20/21) were on conventional mechanical ventilation. Median time 1 LUS score was 15.5 (11, 23.5) in ARDS, 7 (2, 11) in LRTI and 2 (1, 7) in control group (p=0.001). Pairwise comparison showed higher LUS scores in ARDS than in LRTI and control group (p=0.015, 0.003). There was no significant difference in LUS scores between LRTI and control group (p=0.27). Median time 2 LUS score was 16.5 (11, 22) in ARDS and 6 (2,10) in LRTI.

Conclusions: Children with ARDS had higher LUS scores within 24 hours of respiratory failure compared to children with respiratory failure secondary to LRTI or non-respiratory illnesses. LUS scores for ARDS remained during the first 48 hours. Effects of ventilatory setting on LUS scores need to be further investigated in future studies.