Effect of length of storage of red blood cell units on outcome in critically ill children

Introduction

Transfusion is a common treatment in the pediatric ICU (PICU). No study has evaluated the clinical effect of length of storage of red blood cell (RBC) units in children. We undertook an analysis of a large PICU transfusion database to assess any effect of RBC length of storage on clinical outcome in children admitted to a PICU.

Methods

A prospective, observational study conducted in 30 North American PICUs between September 2004 and March 2005 [1]. Data collected on consecutive patients aged <18 years with a PICU stay >48 hours included length of storage (days) for transfused RBC units, daily severity of illness score (multiple organ dysfunction syndrome (MODS)), PICU length of stay, and 28-day mortality. Data were analyzed in transfused patients with recorded length of storage according to the oldest RBC unit length of storage per patient. The primary outcome measure was development of new or progressive MODS after transfusion. The secondary outcomes analyzed were 28-day mortality and PICU length of stay. Odds ratios were adjusted for age, number of MODS at admission and total number of transfusions using a multiple logistic regression model.

Results

From a total of 977 enrolled children, 49% (475) were transfused with 2,146 transfusion events: 115 (24%) were transfused once and 360 (76%) had multiple transfusions. The length of storage was recorded for 1,288 transfusions (60%) with a median length of storage of 14 days. The recorded length of storage for at least one RBC unit was known in 329 transfused patients (69%). For patients receiving blood older than the median length of storage (>14 days), the adjusted odds ratio for development of new or progressive MODS was 1.81 (95% CI = 1.03 to 3.18, P < 0.01). There were no significant differences in the total length of PICU stay (adjusted mean difference +0.04 days, 95% CI -0.04 to +0.13) or mortality odds ratios (0.94, 95% CI = 0.33 to 2.54).

Conclusion

In children admitted to the PICU, transfusion of RBC units stored for more than 14 days seems to be associated with a significantly increased risk of MODS. Further studies are warranted to ascertain the effect of RBC unit length of storage on outcome in critically ill children.