Lung Ultrasound in Pediatric Asthma - Characterizing Baseline Findings Outside of Acute Exacerbations

Background: Lung ultrasound (LUS) has been shown to be an effective tool to rapidly diagnose certain causes of pediatric respiratory distress in the emergency department. However, very little is known about LUS findings in pediatric asthma outside of acute exacerbations. Objectives: The primary objective of this study was to characterize LUS findings in a cohort of pediatric patients with a definitive diagnosis of asthma, outside of an asthma exacerbation. Methods: Eligible patients, aged 6 to 17 years old and diagnosed with asthma, underwent LUS during an outpatient visit. LUS was conducted using a six-zone scanning protocol. A positive LUS was defined by one or more of the following: ≥3 B-lines per intercostal space, pulmonary consolidation and/or pleural anomaly. Images were interpreted by an expert sonographer blinded to patient clinical characteristics. Results: 52 patients were included. 10/52 patients had a positive LUS (19.2%, 95CI 8.3-30.1%). Of those with positive LUS findings, 8 had B lines, 7 had consolidations <1cm, 1 had a pleural line abnormality and 1 had a consolidation >1cm. Positive findings were seen in the right anterior and lateral zones in 60% of participants and were limited to 1-2 intercostal spaces within one lung zone in 100% of participants. Conclusion: To our knowledge, this is the first report of LUS findings in outpatient pediatric asthma. Positive LUS findings in asthmatic children can be seen outside of acute exacerbations. Such findings need to be taken into consideration when using LUS for the acute evaluation of a pediatric patient with asthma.