Diagnostic utility of lung ultrasound in infants under one year of age following cardiac surgery: a prospective observational study

INTRODUCTION: Pediatric cardiac surgery is frequently complicated by acute respiratory failure (ARF). This study aims to address gaps in understanding the role of lung ultrasound (LUS) in pediatric cardiothoracic surgery, identify associations between LUS findings and clinically evident ARF, and assess their diagnostic value to improve prevention and management strategies. OBJECTIVE: To evaluate the diagnostic utility of lung ultrasound in children following radical correction of congenital heart defects (CHD) using cardiopulmonary bypass. MATERIALS AND METHODS: A prospective observational study included 71 children following radical correction of CHD, with sample size calculated for 80 % power and α = 0.05. ARF was assessed upon transferring from ICU. Descriptive statistics, correlation analysis, univariate logistic regression, and ROC analysis were performed. RESULTS: Alveolar consolidation syndrome (> 12 points) in lateral lung regions, particularly in the left lung, and marked interstitial syndrome (> 29 points) were significantly associated with ARF, demonstrating high diagnostic accuracy. The most clinically significant parenchymal lesions were localized in the left lung, especially in lateral zones. Alveolar consolidations without air bronchograms showed the highest discriminative power, whereas lesions in anterior lung regions showed no significant correlation to ARF. Local B+ lines were associated with lower ARF probability. LUS parameters demonstrated superior diagnostic value compared to conventional intraoperative and instrumental methods. CONCLUSIONS: ARF is typically characterized by severe interstitial syndrome combined with alveolar consolidations — either without air bronchograms or with dynamic air bronchograms. Alveolar consolidation, particularly in lateral zones of the left lung, demonstrated the highest diagnostic value. Key predictors were total consolidation score > 12 (AUC = 0.899) and interstitial score > 29 (AUC = 0.870). The spatial localization of abnormalities suggests potential biphasic pathophysiological mechanisms of ARF and supports targeted LUS of these regions to personalize intensive therapy and optimize respiratory monitoring in children. Further studies are warranted.