Association between the length of storage of transfused leukoreduced red blood cell units and hospital-acquired infections in critically ill children: A secondary analysis of the TRIPICU study.

Objective: Evaluate the association between leukoreduced red blood cell (RBC) storage length and hospital-acquired infection (HAI) incidence rate in critically ill children.

Background: RBC transfusions are common in critically ill children. Despite their benefits, observational studies suggest an association between them and HAIs. One possible mechanism for increased HAI is transfusion-related immunomodulation due to bioactive substances' release as transfused blood ages.

Methods: In this secondary analysis of the 'Transfusion Requirement in Paediatric Intensive Care Units' (TRIPICU) study, we analysed a subset of 257 participants that received only one pre-storage leukoreduced RBC transfusion. RBC storage length was classified as 1) transfusion of 'fresh' RBCs (≤10 days), 2) transfusion of 'stored' RBCs (21-34 days), and 3) transfusion of 'long-stored' RBCs (≥35 days). All were compared to a 'golden' period (11-20 days), representing the time between 'fresh' and 'stored'. We used quasi-Poisson multivariable regression models to estimate the HAI incidence rate ratio (IRR) and corresponding 95% confidence interval (CI).

Results: We found that the association between the length of storage time of leukoreduced RBCs and HAIs was not significant in the 'fresh' group (IRR 1.23; 95% CI 0.55, 2.78) and the 'stored' group (IRR 1.61; 95% CI 0.63, 4.13) when compared to the 'golden' period. However, we observed a statistically significant association between the 'long-stored' group and an increase in the HAI incidence rate (IRR 3.66; 95% CI 1.22, 10.98).

Conclusion: Transfusion of leukoreduced RBC units stored for ≥35 days is associated with increased HAI incidence rate in haemodynamically stable, critically ill children.