Blood Transfusion Volume During Emergency Aortic Dissection Surgery Tied to Prolonged Ventilation

Patients who receive more than four units of packed red blood cells during emergency surgery for acute type A aortic dissection face a markedly higher likelihood of needing mechanical ventilation for more than a day after the operation, according to a retrospective observational study drawing on data from the national RENADA-RO registry. Among 125 consecutive patients operated on between 2015 and 2024, 92.5 percent of those who crossed that transfusion threshold required prolonged mechanical ventilation, compared with 54.2 percent of those who received four units or fewer, a difference the authors report as statistically significant.

The study, published in BMC Surgery, set out to address a gap that cardiac surgical teams confront regularly: while blood transfusion is common during emergency repair of this life-threatening dissection of the body’s main artery, clinically meaningful transfusion thresholds linked to prolonged mechanical ventilation have remained poorly defined. The researchers defined prolonged mechanical ventilation as invasive mechanical ventilation lasting longer than 24 hours after surgery, and used receiver operating characteristic analysis to identify the intraoperative packed red blood cell volume most strongly associated with that outcome.

That analysis pointed to more than four units as the optimal cut-off, with an area under the curve of 0.837. Patients exceeding the threshold also experienced significantly higher rates of major postoperative complications, including acute kidney injury, sepsis, and multiple organ dysfunction syndrome. The findings suggest that the volume of blood a patient receives in the operating room may serve as a marker for how smoothly the postoperative course will unfold.

To test whether the association held up beyond raw correlations, the team turned to multivariable logistic regression. After adjusting for age, cardiopulmonary bypass time, and circulatory arrest, transfusion of more than four packed red blood cell units remained associated with prolonged mechanical ventilation, with an adjusted odds ratio of 9.71 and a 95 percent confidence interval of 3.02 to 31.18, at a p-value below 0.001. The model achieved a C-statistic of 0.798, indicating reasonable discriminatory power for the outcome.

The authors are careful about what these numbers do and do not demonstrate. Because transfusion volume may also reflect operative complexity and disease severity, they write, the findings should be interpreted as demonstrating an association rather than a causal relationship. In other words, patients who bleed more heavily or endure longer, more complicated operations naturally receive more blood, and those same factors may independently drive the need for extended ventilatory support. The study cannot disentangle these effects entirely, even with statistical adjustment.

Acute type A aortic dissection is among the most urgent conditions in cardiovascular surgery, requiring emergency repair of a tear in the inner layer of the aorta where it ascends from the heart. Such operations typically involve cardiopulmonary bypass, and in many cases circulatory arrest, in which blood flow is temporarily stopped to allow the surgeon to work. Each of these elements contributes to bleeding risk and to the decision to transfuse, which is why intraoperative blood transfusion is so common in this setting.

The retrospective design, using prospectively collected registry data from a single national cohort, carries inherent limitations. The adjustment set was limited to prespecified covariates available in the registry, and other factors that influence both transfusion volume and postoperative respiratory outcomes may not have been captured. The single-country cohort of 125 patients, while consecutive, may not generalize to all practice settings.

With those caveats in place, the authors frame the identified threshold of four units as hypothesis-generating. They state that it requires external validation before any clinical implementation, meaning that other centers and datasets would need to reproduce the association before the cut-off could inform transfusion decisions or risk stratification in the operating room.

What the study does offer is a quantified signal. A patient receiving more than four units of packed red blood cells during emergency aortic dissection repair had roughly a ninefold higher adjusted odds of remaining on a ventilator beyond the first postoperative day, alongside a heavier burden of kidney injury, sepsis, and multi-organ dysfunction. For surgical teams weighing transfusion strategy in the operating room, that signal, once validated elsewhere, could sharpen conversations about when blood product use signals elevated postoperative risk.

Subject of Research: Association between intraoperative packed red blood cell transfusion volume and prolonged mechanical ventilation after emergency repair of acute type A aortic dissection

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

Article References: Robu, C., Filipescu, D., Matei, D.-C., Văleanu, L., Bubenek-Turconi, Ş.-I., Geavlete, O. D., Robu, M., Radu, R. I., Ciobanu, C., Ştiru, O., Iliescu, V. A., & Chioncel, O. D. (2026). Intraoperative packed red blood cell transfusion volume is associated with prolonged mechanical ventilation after surgical repair of acute type A aortic dissection. BMC Surgery. https://doi.org/10.1186/s12893-026-04323-y

Image Credits: AI Generated

DOI: 10.1186/s12893-026-04323-y

Keywords: acute type A aortic dissection, packed red blood cell transfusion, prolonged mechanical ventilation, cardiac surgery, RENADA-RO registry, receiver operating characteristic analysis, multivariable logistic regression, acute kidney injury, sepsis, multiple organ dysfunction syndrome, cardiopulmonary bypass, retrospective observational study