Bedside Lung Ultrasound for Early Postoperative Risk Stratification for Prolonged Mechanical Ventilation After Liver...

Objectives: Pulmonary complications remain a major determinant of postoperative morbidity following liver transplantation and frequently lead to prolonged mechanical ventilation (PMV). This study aimed to evaluate the value of lung ultrasound (LUS) for early postoperative risk stratification of PMV and to develop a multivariable model integrating LUS with conventional clinical variables. Methods: In this prospective cohort study, 116 adults undergoing primary liver transplantation were enrolled. A standardized 12-zone LUS examination was performed within 1-3 h of ICU admission. PMV was defined as the need for mechanical ventilation for ≥24 h. Multivariable logistic regression analysis was constructed by sequentially incorporating perioperative variables and postoperative PaO₂/FiO₂, followed by LUS. Model performance was evaluated using discrimination, calibration, bootstrap internal validation, and decision curve analysis. Results: PMV occurred in 39.7% (n = 46) of the patients. Those requiring PMV had significantly higher early postoperative LUS scores than patients extubated within 24 h (median: 18.0 vs. 12.0, p < 0.001). LUS scores were inversely correlated with oxygenation (SpO₂/FiO₂ ratio, ⍴ = -0.615, p < 0.001). LUS remained independently associated with PMV (OR = 1.52, 95% CI: 1.27-1.83). LUS alone demonstrated good discrimination (AUC: 0.830). After postoperative PaO₂/FiO₂ was included in the clinical model, incorporation of LUS significantly improved model discrimination (AUC: 0.935, 95% CI: 0.894-0.976) compared with the model without LUS (AUC: 0.862, DeLong p = 0.011). Decision curve analysis showed greater net benefit of the LUS-integrated model across clinically relevant threshold probabilities. Conclusions: Early postoperative LUS is independently associated with prolonged mechanical ventilation after liver transplantation. Integration of LUS into a multivariable framework provides incremental prognostic information beyond conventional postoperative respiratory assessment and may improve early postoperative risk stratification. External validation is required before clinical implementation.