Lung Ultrasound-Guided Surfactant Therapy in Neonatal Pneumothorax and Pulmonary Hemorrhage: Pathophysiology, Diagnostic Ultrasonography, and Emerging Clinical Approaches.

BACKGROUND AND OBJECTIVES: Lung ultrasound (LUS) has fundamentally transformed neonatal respiratory diagnostics, offering a radiation-free, bedside-applicable modality capable of guiding surfactant therapy, characterizing pulmonary pathology, and monitoring treatment response in real time. While surfactant replacement therapy is firmly established for neonatal respiratory distress syndrome (RDS), its role in acute complications-specifically pulmonary hemorrhage (PH) and pneumothorax (PTX)-remains uncertain and heterogeneous in clinical practice. This review examines how LUS-based phenotyping can improve the diagnostic precision and therapeutic sequencing of surfactant administration in these high-risk scenarios, and how comorbidities such as hemodynamically significant patent ductus arteriosus, persistent pulmonary hypertension, sepsis, and coagulopathy modulate clinical outcomes.

MATERIALS AND METHODS: We conducted a structured narrative review of studies published from 2020 onward, sourced from PubMed, Web of Science, Semantic Scholar, and Mendeley, using PRISMA-inspired selection principles. The search combined terms including "lung ultrasound," "neonatal POCUS," "surfactant therapy," "pulmonary hemorrhage," "neonatal pneumothorax," and "LUS score." Studies focusing on neonatal populations, clinical LUS applications, and surfactant use in PH and PTX were prioritized.

RESULTS: Quantitative LUS scoring systems (range 0-18) predict surfactant need and re-dosing with AUC values of 0.85-0.87, outperforming clinical estimates alone. In PH, LUS reveals dense consolidation with alveolar flooding patterns, guiding the timing of rescue surfactant after hemodynamic stabilization; response monitoring via serial LUS is feasible and informative. In PTX, hallmark signs-absent lung sliding, loss of B-lines, and the pathognomonic lung point-allow diagnosis within seconds, guiding immediate thoracentesis and subsequent surfactant administration if underlying RDS is confirmed. Nationally implemented LUS protocols in neonatal intensive care units have demonstrated significant reductions in radiation exposure without compromising diagnostic accuracy.

CONCLUSIONS: LUS-guided decision algorithms-integrating ultrasonographic phenotyping, quantitative scoring, and hemodynamic assessment-represent the current best framework for individualizing surfactant therapy in neonatal PH and PTX. Standardization of POCUS training and protocol implementation in neonatal units is essential. Prospective multicenter trials are urgently needed to define optimal indications, timing, and dosing in these vulnerable populations.