Lung ultrasound scoring in invasive mechanically ventilated children with severe bronchiolitis

Objective: Lung ultrasound (LUS) is an emerging tool that may be used in the diagnosis and follow-up of children with viral bronchiolitis. In this study, we describe LUS abnormalities in children receiving invasive mechanical ventilation (IMV) for severe bronchiolitis in the pediatric intensive care unit (PICU). Our aim was to semiquantify the loss of aeration and examine the association between serial LUS scores and oxygenation anomaly, as a marker of disease severity. Design: Prospective, observational study in a single-center PICU. Methods: LUS was performed by multiple observers using two different LUS scoring systems (counting B-lines and aeration score) in 17 patients in the PICU, generating 320 images. Oxygen saturation index (OSI) was the primary outcome marker to describe the severity of oxygenation anomaly. Results: Pulmonary aeration was moderately impaired with a homogeneous anterolateral pattern. LUS scores worsened after 24 hours, to improve in subsequent days. Both LUS scores were positively correlated with OSI on the first day of IMV (counting B-lines P =.034, r =.52 and LUS aeration score P =.017, r =.57), but not thereafter. There was considerable variability in the LUS scores despite moderate to high agreement between the observers. Conclusions: In children receiving IMV for severe bronchiolitis, pulmonary aeration is moderately impaired. LUS scores positively correlate with severity of oxygenation anomaly only in the acute phase of disease. We speculate that with the progression of disease other factors affect LUS patterns (eg, fluid overload, atelectasis), which may complicate the interpretation of LUS in follow-up of this specific cohort in the PICU.