Association Between Length of Storage of Transfused Packed RBC Units and Outcome of Surgical Critically Ill Adults: A Subgroup Analysis of the Age of Blood Evaluation Randomized Trial*

Abstract

Objectives: The Age of Blood Evaluation (ABLE) study reported no clinical benefit in fresher compared with standard delivery RBC units (length of storage: 6.9 ± 4.1 vs 22.0 ± 8.4 d, respectively). Perioperative patients are often anemic, at risk of blood loss, and more exposed to RBC transfusions. We address the question whether fresh RBC units are safer than standard delivery RBC units in perioperative ICU patients. Design: Subgroup analysis of surgical nontrauma adults enrolled in the ABLE randomized controlled trial. Setting: ICUs. Patients: Three hundred twenty surgical patients among the 2,510 ICU adults recruited in the ABLE study who had a request for a first RBC transfusion in the first week in ICU stay and an anticipated length of mechanical ventilation greater than or equal to 48 hours. We included perioperative patients but excluded elective cardiac surgery and trauma. Interventions: Surgical participants were allocated to receive either RBC units stored less than or equal to 7 days or standard issue RBC. MEASUREMENTS AND MAIN RESULTS: The primary outcome was 90-day all-cause mortality. One hundred seventy-two perioperative patients were allocated to the fresh and 148 to the standard group. Baseline data were similar. The length of storage was 7.2 ± 6.4 in fresh and 20.6 ± 8.4 days in standard group (p < 0.0001). The 90-day mortality was 29.7% and 28.4%, respectively (absolute risk difference: 0.01; 95% CI –0.09 to 0.11; p = 0.803). No significant differences were observed for all secondary outcomes, including 6-month mortality, even after adjustment for age, country, and Acute Physiology and Chronic Health Evaluation score. Conclusions: There was no evidence that fresh red cells improved outcomes as compared to standard issue red cells in critically ill surgical patients, consistent with other patients enrolled in the ABLE trial.