Hypothesis: Blood components undergo changes during storage that may affect the recipient, including the release of bioactive agents, with significant immune consequences. We hypothesized that transfusion of old blood increases infection risk in severely injured patients.
Design: Prospective cohort study.
Setting: Urban level I regional trauma center.
Patients: Sixty-one trauma patients with an Injury Severity Score greater than 15, age older than 15 years, and survival longer than 48 hours who were transfused with 6 to 20 U of red blood cells in the first 12 hours after injury were studied. By means of blood bank records, the age of each unit of blood was determined.
Intervention: Transfusion of allogeneic red blood cells.
Main outcome measurements: Major infectious complications.
Results: The early (<12 hours) transfusion requirement was 12 +/- 0.6 U, with a mean age 27 +/- 1 days. Major infections developed in 32 patients (52%). Age and Injury Severity Score were not significantly different between patients who developed infections and those who did not (age, 39 +/- 4 vs 36 +/- 3 years; Injury Severity Score, 33 +/- 1.5 vs 29 +/- 1.5). Transfusion of older blood was associated with subsequent infection; patients who developed infections received 11.7 +/- 1.0 and 9.9 +/- 1.0 U of red blood cells older than 14 and 21 days, respectively, compared with 8.7 +/- 0.8 and 6.7 +/- 0.08 in patients who did not develop infections (both P<.05, t test). Multivariate analysis confirmed age of blood as an independent risk factor for major infections.
Conclusions: Transfusion of old blood is associated with increased infection after major injury. Other options, such as leukocyte-depleted blood or blood substitutes, may be more appropriate in the early resuscitation of trauma patients requiring transfusion.