Photo by Elise Amendola
Blood for transfusion
New research suggests that, overall, the age of transfused red blood cells (RBCs) does not significantly impact outcomes in critically ill adults, but, in some cases, older RBCs may be the better choice.
The study showed no significant difference in 90-day mortality whether patients received RBCs stored for a mean of 11.8 days or 22.4 days.
Likewise, there were no significant differences in most other study endpoints.
However, febrile nonhemolytic transfusion reactions were more frequent in the short-term storage group.
And among the most severely ill patients, the transfusion of older RBCs was associated with fewer deaths at 90 days.
“Older blood appears to be like a good red wine—better with some age,” said study author D. James Cooper, MD, of Monash University and Alfred Hospital in Melbourne, Victoria, Australia.
“The findings of our trial confirm that the current duration of storage of red blood cells for transfusion is both safe and optimal.”
Dr Cooper and his colleagues reported their findings in NEJM.
The researchers conducted this trial from November 2012 through December 2016 at 59 centers in 5 countries—Australia, New Zealand, Ireland, Finland, and Saudi Arabia.
The study included nearly 5000 critically ill adults who were randomized to receive either the freshest available RBCs or the oldest available RBCs.
There were 2457 patients in the short-term storage group, where the mean RBC storage duration was 11.8 ± 5.3 days. And there were 2462 patients in the long-term storage group, where the mean RBC storage duration was 22.4 ± 7.5 days.
Baseline characteristics were largely similar between the 2 groups. However, patients were significantly older in the short-term storage group, with a mean age of 62.5 ± 16.8 years, compared to 61.4 ± 17.3 years in the long-term storage group (P=0.02).
The median time from randomization to first RBC transfusion was similar between the groups—1.6 hours in the short-term group and 1.5 hours in the long-term group. The mean number of RBC units was also similar—4.1 ± 6.0 and 4.0 ± 6.2, respectively. The use of other blood products was similar as well.
90-day mortality
The study’s primary endpoint was 90-day mortality, which was 24.8% (n=610) in the short-term storage group and 24.1% (n=594) in the long-term storage group. The unadjusted (u) odds ratio (OR) was 1.04 (P=0.57).
When the researchers adjusted for APACHE III risk of death, patient age, hemoglobin at randomization, blood group, and site, the adjusted (a) OR was 1.04 (P=0.59).
When the researchers looked at patient subgroups, they found a significant difference between the storage groups when it came to 90-day mortality according to APACHE III risk of death.
Patients with an APACHE III predicted risk of death at hospital discharge at a median of 21.5% or higher had a significantly higher rate of 90-day mortality if they received the freshest available RBCs rather than the oldest available RBCs—37.7% and 34.0%, respectively (uOR=1.18, P=0.05).
There were no significant differences in 90-day mortality in the other subgroups.
Secondary endpoints
There were no significant between-group differences in secondary endpoints, with the exception of febrile nonhemolytic transfusion reaction. The incidence of this outcome was 5.0% in the short-term storage group and 3.6% in the long-term group (uOR=1.42, P=0.01; aOR=1.45, P=0.01).
Other secondary endpoints included (data in the short-term and long-term groups, respectively):
- Death at day 28 (19.4% and 18.8%, uOR=1.04, P=0.61)
- Death at day 180 (28.5% and 28.1%, uOR=1.02, P=0.75)
- Persistent organ dysfunction or death at day 28 (23.3% and 22.3%, uOR=1.06, P=0.39)
- New bloodstream infection (1.4% and 1.6%, uOR=0.90, P=0.65)
- Duration of hospital stay (median 14.5 days and 14.7 days, P=0.42)
- Duration of stay in the intensive care unit (median 4.2 days for both, P=0.86)
- Invasive mechanical ventilation (58.6% and 59.3%, uOR=0.97, P=0.64)
- Renal-replacement therapy (13.9% and 14.6%, uOR=0.97, P=0.48).
