Longer blood storage is associated with suboptimal outcomes in high-risk pediatric cardiac surgery

Background: The negative effects of long-term storage of allogeneic red blood cells (RBCs) on outcomes in adult cardiac surgery have been established, but evidence of a similar effect in pediatric cardiac surgery is limited. Methods: The weighted average duration of storage for RBC units used in 1,225 pediatric cardiac operations was determined. Operations were divided into high RBC use (more than 4 units or more than 150 mL/kg) or low RBC use. For both categories, associations between storage duration and surgical outcomes, adjusted for relevant patient characteristics, were evaluated. Results: High RBC use was associated with higher surgical complexity. Storage duration for patients who received low RBC volumes was not associated with surgical outcomes. For patients with high RBC transfusion volumes, longer storage duration (per day) was associated with higher odds of bleeding complications (odds ratio 1.029, p = 0.07), renal insufficiency (odds ratio 1.085, p = 0.001), higher inotrope score after surgery (12 to 24 hours +0.08, p = 0.002; 24 to 48 hours +0.07, p < 0.001), greater chest tube drainage (24 hours +1.5 mL/kg, p < 0.001), longer postoperative hospitalization (+0.3 days p = 0.02), and increased in-hospital mortality (odds ratio 1.054, p = 0.03). Effects of RBC transfusions on postoperative bleeding were greatest for storage duration longer than 14 days. Conclusions: The freshest RBC units available should be used for pediatric cardiac operations expected to require more than 4 units or more than 150 mL/kg of allogeneic RBC transfusions, with no units more than 14 days old being transfused whenever possible.