Intraoperative packed red blood cell transfusion volume is associated with prolonged mechanical ventilation after surgical repair of acute type A aortic dissection

Intraoperative blood transfusion is common during emergency surgery for acute type A aortic dissection (AAAD). However, clinically meaningful transfusion thresholds associated with prolonged mechanical ventilation (PMV) remain poorly defined. We conducted a retrospective observational study of 125 consecutive patients undergoing emergency AAAD repair between 2015 and 2024 using prospectively collected data from the national RENADA-RO registry. PMV was defined as invasive mechanical ventilation lasting > 24 h postoperatively. Receiver operating characteristic (ROC) analysis identified the optimal intraoperative packed red blood cell (PRBC) transfusion threshold associated with PMV. Multivariable logistic regression was performed to evaluate the association between PRBC transfusion and PMV after adjustment for prespecified covariates. ROC analysis identified > 4 PRBC units as the optimal cut-off (AUC 0.837). Patients receiving > 4 units had significantly higher rates of PMV (92.5% vs. 54.2%, p < 0.001) and major postoperative complications, including acute kidney injury, sepsis, and multiple organ dysfunction syndrome. After adjustment for age, cardiopulmonary bypass time, and circulatory arrest, transfusion > 4 PRBC units remained associated with PMV (adjusted OR 9.71, 95% CI 3.02–31.18, p < 0.001; C-statistic 0.798). Intraoperative transfusion exceeding four PRBC units was associated, after adjustment for the available covariates, with PMV and increased postoperative morbidity after AAAD repair. Because transfusion volume may also reflect operative complexity and disease severity, these findings should be interpreted as demonstrating an association rather than a causal relationship. The identified transfusion threshold should be considered hypothesis-generating and requires external validation before clinical implementation.