Rib-Indexed POCUS versus Chest X-Ray for Lung Recruitment Assessment in Ventilated Neonates with Moderate-Severe ARDS on Pulmonary Surfactant Therapy: a prospective observational study

Background Neonatal acute respiratory distress syndrome (NARDS) is associated with high morbidity and mortality. Current lung recruitment assessment methods, such as chest X-ray (CXR) and computed tomography (CT), involve ionizing radiation, limiting serial use in neonates. This study evaluated the feasibility of rib-indexed point-of-care ultrasound (POCUS) as a radiation-free alternative for monitoring lung recruitment in mechanically ventilated neonates with moderate-to-severe NARDS receiving pulmonary surfactant (PS) therapy. Methods A prospective observational study was conducted in a tertiary neonatal intensive care unit (NICU) from September 2023 to September 2024. Thirty-five neonates were enrolled. Lung recruitment was assessed via anterior‒posterior approach POCUS and CXR before and 6 hours after PS therapy combined with prone ventilation. Results Posterior approach POCUS demonstrated high concordance with CXR (ICC: 0.957 preintervention, 0.955 postintervention; kappa: 0.942–0.946), whereas anterior approach POCUS showed low consistency (ICC: 0.132–0.114; kappa: −0.029 to − 0.047) despite moderate Spearman correlations (0.673–0.913). Subgroup analyses revealed no significant associations between physiological parameter changes and clinical outcomes [mechanical ventilation duration, extracorporeal membrane oxygenation (ECMO) criteria, mortality]. Interoperator reliability was excellent. Conclusions Rib-indexed posterior approach POCUS is a reliable, radiation-free modality for real-time lung recruitment assessment in neonates with NARDS, demonstrating noninferiority to CXR. Notably, our study is the first to propose the innovative use of Doppler ultrasound-guided vascular landmark identification to assist in first rib localization in neonates. This protocol addresses critical limitations of conventional imaging, offering a safer alternative for dynamic monitoring in neonatal critical care. Future multicentre studies integrating CT validation are warranted to confirm broader applicability. Trial Registration: The trial was prospectively registered with the Chinese Clinical Trial Registry (ChiCTR2300074652) on August 11, 2023.