Supplementary Material for: A State-wide Retrospective Cohort Study Examining Effects of Transfusing Old Blood Products in Vascular Surgical Patients

Introduction
We investigated the effects of transfusing blood products close to the expiration date (i.e., ≥35 days packed red blood cells (PRBCs) and >3 days platelets (PLTs)) on vascular patients.
Methods
We retrospectively examined all PRBCs and PLTs transfusions in patients who underwent vascular procedures without cardiopulmonary-bypass in Queensland from 2007 to 2013. Mortality, length of stay (LOS) and blood product quantities were compared in patients transfused exclusively with PRBCs <21 days vs PRBCs ≥35 days and PLTs ≤3 days vs PLTs >3 days.
Results
No significant mortality difference was found between patients transfused fresh vs old PRBCs (26/493 (5.3%) vs 6/152 (3.9%); OR 0.75; 95%CI, 0.3-1.9). Patients transfused fresh PRBCs experienced a longer LOS (11 days (IQR, 7-20) vs 10 days (IQR, 7-15); 95% CI, -4.8 to -0.24), and more PRBC units (3.9±4.5 units vs 2.1±1.3 units; 95%CI, -2.3 to -0.9). Among patients transfused PLTs, there were no significant differences in mortality (24/124 (19.4%) vs 14/78 (17.9%); OR 1.0; 95%CI, 0.5 to 2.3) between patients transfused fresh vs old PLTs.
Conclusion
Within the limitations of the retrospective study design, transfusion of older PRBCs or PLTs was associated with fewer transfused units, shorter hospital stays but no difference in mortality.