OA2-AM24-SN-23 - Expired Blood Transfusion and Mortality Outcomes in Combat Trauma Patients

Regulations allow transfusion of expired blood if clinically indicated. Although rare in civilian settings, there is precedent in the US military for transfusing expired blood to combat casualties; patient outcomes have not been reported. We hypothesized that recently expired blood can sustain hemorrhaging patients until surgical control is achieved. This study assessed whether expired blood was associated with mortality in combat trauma patients.

Study

Design/Methods:

Retrospective analysis of the Joint Trauma Registry and Armed Services Blood Program databases evaluated combat casualty records (2001-2023). The intervention of interest was transfusion of at least one unit of whole blood (WB), red blood cells (RBC), or platelets within seven days past expiration. The outcome of interest was mortality at discharge (alive/dead) from an in-theater military treatment facility. Logistic regression evaluated the association between mortality and expired RBC use, total expired units, total transfusion volume, traumatic brain injury, and amputation. To explore extreme cases, 10 patients who received the most expired RBCs by volume or storage duration were qualitatively described. Expired WB and platelet sample sizes were too small for statistical analysis so recipients were qualitatively described.

Results/Findings:

Available data included 15,693 blood product recipients and 360,664 blood product records. Of 100 patients who met inclusion criteria, 86 received expired RBCs, 11 received expired WB, and three received expired platelets. RBC case-control matching (1:4 ratio) yielded 344 controls. Mortality at discharge was 11.6% for expired RBC recipients and 13.4% for the control cohort (p=0.97). After adjustment for injury severity, expired RBCs (OR=0.40 [95% CI, 0.14-1.16];p=0.09), total expired units (OR=1.10 [0.94-1.29];p=0.24), traumatic brain injury (OR=1.89 [0.94-3.80];p=0.07), and amputation (OR=1.09 [0.47-2.55];p=0.84) were not significantly associated with mortality. “Total transfusion volume” was the only variable significantly associated with mortality (OR=1.02 [1.01-1.03];p< 0.001). Two of 10 patients who received the most expired RBCs were deceased at discharge. All 14 expired WB and platelet recipients were alive at discharge.

Conclusions:

Transfusion of RBCs within seven days past expiration was not associated with increased mortality in combat trauma patients. Recipients of expired WB and platelets did well but conclusions are limited by small sample sizes. Previous studies have shown that combat casualties with indications for transfusion have better outcomes when transfusion is initiated early and sustained as long as possible; a futility threshold has not been identified. Expired blood should be further investigated for a possible role in extending the blood supply in combat trauma care.