Dynamic Evolution Characteristics and Nursing Intervention Windows of Perioperative Deep Vein Thrombosis in Patients...

Deep vein thrombosis (DVT) is a major complication after lower extremity traumatic fractures. Current nursing assessment is largely postoperative-centered and may overlook risk evolution during the preoperative waiting period.

In this prospective observational cohort study, 948 patients with lower extremity traumatic fractures were enrolled between January 2019 and January 2026. Serial color Doppler ultrasound examinations were performed at five timepoints: admission, preoperative, postoperative day 1, postoperative day 3, and discharge. Univariate and multivariate logistic regression analyses were used to identify predictors of preoperative DVT. A dynamic nomogram was developed and evaluated using receiver operating characteristic analysis, calibration, decision curve analysis, and SHAP-based interpretation.

The overall incidence of perioperative DVT was 32.9% (312/948). DVT showed a distinct "twin-peak" temporal pattern, with the highest incidence during the preoperative waiting period and a second peak on postoperative day 3. Thrombi also shifted from predominantly distal veins at admission to greater proximal involvement after surgery. Independent predictors of preoperative DVT were age >65 years, preoperative waiting time >3 days, D-dimer >1.85 mg/L, albumin <35 g/L, and time from injury to admission >12 h. The nomogram showed good discrimination (AUC 0.905, 95% CI 0.882-0.928), outperforming individual predictors such as D-dimer (AUC 0.796). Decision curve analysis demonstrated clinical net benefit, and SHAP analysis identified D-dimer and albumin as the most influential variables.

Perioperative DVT after lower extremity fractures follows a dynamic pattern with a critical preoperative risk window. The proposed nomogram may support stage-specific nursing assessment and targeted interventions, particularly by reducing preoperative delay and optimizing nutritional status.