Diagnostic Accuracy of Lung Ultrasound for Pneumonia in Acutely and Critically Ill Neonates, Children, and Young Adults: A Systematic Review and Meta-Analysis

<b>Background:</b> Pneumonia remains a major cause of morbidity and mortality among critically ill children. Lung ultrasound has emerged as a promising bedside diagnostic tool. <b>Methods</b>: A systematic review and meta-analysis across PubMed, Embase, The Cochrane Library, Scopus, World Health Organization Libraries, Epistemonikos, and MedRxiv was conducted to evaluate the diagnostic accuracy of lung ultrasound for pneumonia in paediatric patients. Publication bias was evaluated using the generalised Egger's test. Diagnostic performance metrics, including sensitivity, specificity, and the area under the receiver operating characteristic curve were pooled using a bivariate random-effects model. <b>Results:</b> Thirty studies comprising a total of 4356 children were included. The studies were of high methodological quality, with minimal heterogeneity. Lung ultrasound pooled sensitivity was 91% (95% CI: 87-94%), and specificity was 90% (95% CI: 83-94%). The ROC curve was 0.95 (95% CI: 0.90-0.95), indicating excellent diagnostic performance. <b>Conclusions:</b> LUS is a reliable and accurate imaging modality for diagnosing pneumonia in critically ill children. The findings support its use as a first-line diagnostic tool in emergency and intensive care settings. PROSPERO Research registration number: CRD42021223679.