Diaphragmatic ultrasound and thoracic fluid content for prediction of non-invasive ventilation failure in neonates: a randomized controlled trial.

Non-invasive ventilation (NIV) remains the standard of care for preterm infants with respiratory distress syndrome (RDS); however, NIV failure is frequent and often linked to adverse outcomes. This study evaluated diaphragmatic ultrasound and thoracic fluid content (TFC) as early predictors of NIV failure in preterm neonates. In this prospective randomized controlled trial, 90 preterm neonates (28-34 gestational weeks) with RDS requiring NIV as initial respiratory support were randomized into three groups: (1) nasal continuous positive airway pressure (nCPAP), (2) nasal intermittent positive pressure ventilation (NIPPV), and (3) nasal high-frequency oscillatory ventilation (NHFOV). Diaphragmatic thickening fraction (DTF) and excursion (DE) were measured by ultrasound, while TFC was assessed using electrical cardiometry (EC). Measurements were obtained within the first 3 h of life and repeated either at 24 h in successful cases or immediately before intubation in failed cases. DTF and DE were significantly higher in neonates with successful NIV compared with those who failed (all p < 0.001), while TFC was significantly higher in failed cases within NIPPV and NHFOV groups (p < 0.001). DTF and DE showed excellent predictive accuracy (AUC 0.90 and 0.89), outperforming TFC (AUC 0.81, p < 0.01). Both DTF (adjusted OR = 0.89, 95% CI 0.83-0.96) and DE (adjusted OR = 0.38, 95% CI 0.20-0.73) independently predicted NIV failure. The combined DTF-TFC model provided the highest discrimination (AUC 0.93, 95% CI 0.89-0.97).

conclusionsDiaphragmatic ultrasound and TFC-derived EC represent simple, non-invasive, and reliable tools for predicting NIV failure in preterms with RDS. CLINICAL

trial registrationclinicaltrials.gov/ NCT07148102; registered August 22, 2025. WHAT IS KNOWN: • NIV is widely used in preterm neonates with RDS, but predicting NIV failure remains challenging. Lung ultrasound score and thoracic fluid content have been explored as bedside predictors of NIV outcomes, with variable accuracy.. • Diaphragmatic ultrasound parameters (DTF and DE) have shown potential in assessing respiratory function in neonates. WHAT IS NEW: • DTF and DE measured by ultrasound show a strong correlation with TFC obtained by EC in predicting NIV failure. Additionally, DTF and DE have higher predictive accuracy than TFC in identifying preterm neonates at risk of NIV failure. • Early assessment of DTF and DE may serve as a valuable bedside tool for monitoring lung function during early application of NIV in preterm infants.