Background
Infants and children undergoing open heart surgery routinely require multiple red blood cell (RBC) transfusions. Children receiving greater numbers of RBC transfusions have increased post-operative complications and mortality. Longer RBC storage age is also associated with increased morbidity and mortality in critically ill children. Whether the association of increased transfusions and worse outcomes can be ameliorated by use of fresh RBCs in pediatric cardiac surgery for congenital heart disease is unknown.
Methods
128 consecutively transfused children undergoing repair or palliation of congenital heart disease with cardiopulmonary bypass who were participating in a randomized trial of washed v. standard RBC transfusions were evaluated for an association of RBC storage age and clinical outcomes. To avoid confounding with dose of transfusions and timing of infection versus timing of transfusion, a subgroup analysis of patients only transfused 1–2 units on the day of surgery was performed.
Results
Mortality was low (4.9%) with no association between RBC storage duration and survival. The post-operative infection rate was significantly higher in children receiving the oldest blood (25–38 days) compared to those receiving the freshest RBCs (7–15 days); (34% v. 7%; p = 0.004). Subgroup analysis of subjects receiving only 1–2 RBC transfusions on the day of surgery (n=74) also demonstrates a greater incidence of infections in subjects receiving the oldest RBC units [0 of 33 (0%) with 7–15 day storage, 1 of 21 (5%) with 16–24 day storage and 4 of 20 (20%) with 25–38 day storage; (p=0.01)]. In multivariate analysis, RBC storage age and corticosteroid administration were the only predictors of post-operative infection. Washing the oldest RBCs (>27 days) was associated with a higher infection rate and increased morbidity compared with unwashed RBCs.
Discussion
Longer RBC storage duration was associated with increased postoperative nosocomial infections. This association may be secondary in part, to the large doses of stored RBCs transfused, from single donor units. Washing the oldest RBCs was associated with increased morbidity, possibly from increased destruction of older, more fragile erythrocytes incurred by washing procedures. Additional studies examining the effect of RBC storage age on post-operative infection rate in pediatric cardiac surgery are warranted.