The impact of RBC storage duration has been evaluated on short-term pulmonary function and immunologic status in mechanically ventilated patients receiving RBC transfusion.

Scientists at the Mayo Clinic (Rochester, MN, USA) conducted a double-blind trial, where 50 patients were randomized to receive fresh RBC with a median storage duration of four days and 50 patients were randomized to receive standard issue RBC with a median storage duration of 26.5 days. All RBC units underwent prestorage leukoreduction. All the patients were mechanically ventilated in the intensive care unit (ICU).

The primary outcome measure of change was in pulmonary function arterial oxygen tension - fractional inspired oxygen (PaO2/FiO2) ratio. Other outcome measures included the immunologic status by estimating levels of tumor necrosis factor-alpha, interleukin-8, C-reactive protein and the coagulation status by measuring fibrinogen, anti-thrombin consumption. Measurements were obtained at baseline and within two hours of the completion of RBC transfusion.

No significant differences between groups were seen in the primary outcome measure of change in PaO2/FiO2 ratio: fresh RBC was 2.5 ± 49.3 and standard issue RBC was -9.0 ± 69.8. Similarly, no significant differences were seen for any of the other outcome measures of pulmonary function such as fraction of dead space ventilation, dynamic and static pulmonary compliance or the immunologic and coagulation status measurements.

Daryl J. Kor, MD, assistant professor of anesthesiology at the Mayo Clinic College of Medicine, said, "Our data do not support a significant effect of RBC storage duration on respiratory, immunologic or coagulation parameters in the immediate posttransfusion period. Previous observational studies linking RBC storage duration and respiratory complications may have suffered from bias and unmeasured confounding, which were more effectively addressed in our double-blind, randomized trial study design." The study was published online on January 26, 2012 in the American Journal of Respiratory and Critical Care Medicine.

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