Risk factors and a predictive model for delayed extubation in children undergoing primary repair of tetralogy of Fallot: a retrospective cohort study with rigorous methodological validation
Objective To identify independent risk factors for delayed extubation (mechanical ventilation 48 h) following primary Tetralogy of Fallot (TOF) repair and to develop a rigorously validated predictive model for clinical use. Methods A retrospective cohort study was conducted involving 189 children treated at Henan Chest Hospital between 2019 and 2023. Patients were stratified into delayed (n = 101) and non-delayed (n = 88) extubation groups. The analytical pipeline incorporated Shapiro–Wilk testing, univariate screening, and LASSO regression with 10-fold cross-validation for variable selection. Multicollinearity was assessed via Variance Inflation Factor (VIF), followed by multivariate logistic regression. Model performance was comprehensively evaluated using ROC curves, calibration plots with the Hosmer–Lemeshow test, and Decision Curve Analysis (DCA). Internal validation was secured through 1000-iteration bootstrap resampling and 10-fold cross-validation. Results Six independent predictors were ultimately retained: inotropic score (OR = 1.999), oxygenation index (OR = 0.990), RVOT diameter (OR = 0.711), CPB time (OR = 1.027), McGoon ratio (OR = 0.114), and postoperative PVOV (OR = 1.947). The model demonstrated excellent discrimination with an AUC of 0.916 (bootstrap-corrected 0.909). Calibration was robust (Hosmer–Lemeshow P = 0.366, Brier score = 0.113), and DCA confirmed significant clinical net benefit across threshold probabilities. Sensitivity analysis highlighted the inotropic score as the most influential variable. Conclusions This internally validated model integrates preoperative anatomical (McGoon ratio, RVOT diameter), intraoperative (CPB time), and postoperative physiological (inotropic score, oxygenation, PVOV) factors. It may serve as a potentially useful tool for early risk stratification and could support a dual-phase assessment strategy to guide targeted interventions in pediatric TOF repair. External validation in independent cohorts and prospective clinical implementation studies are warranted before routine clinical adoption.