ORIGINAL RESEARCH article
Front. Pediatr.
Sec. Neonatology
Early Lung Ultrasound Score Combined with Umbilical Cord-Blood Procalcitonin Improves 1-Year Prognostic Stratification in Preterm Neonates with Respiratory Distress Syndrome
Provisionally accepted
- First Hospital of Tsinghua University, Chaoyang, China
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Background: Respiratory distress syndrome (RDS) remains a major cause of morbidity in very preterm infants. Lung ultrasound score (LUS) provides a bedside assessment of lung aeration and has demonstrated utility for early respiratory decision-making, but its prognostic performance for long-term outcomes is only moderate. Procalcitonin (PCT) measured in umbilical cord blood may reflect perinatal inflammatory exposure and risk of infection-related complications. Methods: We conducted a single-center prospective cohort study enrolling infants born at 24+0 to 33+6 weeks' gestation who were admitted to the NICU within 6 hours of birth and were clinically diagnosed with RDS. Within 6 hours after delivery, a standardized 12-zone LUS and umbilical cord-blood PCT were obtained. The primary endpoint was a composite of bronchopulmonary dysplasia, severe intraventricular hemorrhage, necrotizing enterocolitis, culture-proven sepsis occurring after 72 hours of age, or all-cause death within 12 months' corrected age. Discrimination was evaluated using ROC analysis and DeLong tests. Time-to-first-event associations were examined using multivariable Cox regression. Internal validation used bootstrap optimism correction. Results: Among 290 infants, 110 (37.9%) reached the composite endpoint (event-free proportion 62.1%). LUS alone achieved an AUC of 0.76 (95% CI 0.70–0.82), and PCT alone an AUC of 0.78 (0.72–0.84). A logistic model combining LUS and log-transformed PCT improved discrimination to an AUC of 0.87 (0.83–0.92), outperforming each single marker (paired DeLong p<0.001). At the Youden-optimal operating point, sensitivity was 82% and specificity 80%. In multivariable Cox analysis, the high-risk category defined by the combined model was independently associated with higher hazard of the composite outcome (HR 2.9, 95% CI 2.0–4.1), alongside lower gestational age, lower birthweight, and early-onset infection. Bootstrap optimism-corrected AUC was 0.86. Conclusions: In preterm infants with RDS, early integration of 12-zone LUS and cord-blood PCT improves prediction of 12-month major morbidity or death compared with either marker alone. This bedside approach may support early risk stratification. External validation and impact studies are needed before score-guided management is recommended.
Keywords: lung ultrasound (LUS) score, preterm (birth), Procalcitonin (PCT), prognosis, Respiratory Distress Syndrome
Received: 10 Dec 2025; Accepted: 14 Jan 2026.
Copyright: © 2026 Zheng, Jing, Liu, Gao and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Lei Zheng
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