Identifying Factors Associated with Prolonged Postoperative Mechanical Ventilation in Preterm Infants Undergoing Patent Ductus Arteriosus Ligation Using Machine Learning and SHAP Analysis: A Large-Sample Single-Center Retrospective Analysis

Objectives: To analyze factors associated with prolonged mechanical ventilation (MV) after patent ductus arteriosus (PDA) ligation in preterm infants and identify high-risk patients. Methods: A retrospective analysis (2021–2025) was conducted on preterm infants (≤32 weeks) who underwent PDA ligation. Demographic, preoperative and postoperative data were analyzed; machine learning and SHAP analysis identified associated factors. Results: A total of 271 infants (152 males, 119 females; median gestational age 27 weeks [23–32 weeks], median birth weight 920 g [470–2220 g]) were included. Based on postoperative MV duration ≤6 days or >6 days, 150 cases were assigned to the short MV group and 121 to the prolonged MV group. Significant differences were found between groups in terms of gestational age, birth weight, weight at surgery, PDA diameter, postoperative slowest heart rate, Respiratory Severity Score (RSS), rate of bidirectional PDA shunting, preoperative high-frequency ventilation use, post-ligation cardiac syndrome incidence, and rate of preoperative pulmonary hemorrhage/atelectasis (p < 0.05). RSS was identified as the most central predictor of prolonged postoperative MV duration. RSS > 4.5 was associated with a markedly elevated risk of MV >6 days (AUC = 0.865, sensitivity = 80.2%, specificity = 82.5%). In contrast, birth weight > 1500 g or post-ligation heart rate >135 bpm was correlated with shorter MV duration. Conclusions: High RSS, low birth weight, and slow postoperative heart rate are associated with prolonged postoperative MV. This may aid in identifying infants requiring closer perioperative monitoring.