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Allogeneic packed red blood cells (PRBCs) suppress immunity and influence outcomes. The influence of blood on the risk of infection and death may be related to the duration of storage. We sought to determine whether blood storage duration was associated with infection or death in a large cohort of injury victims. We reviewed a cohort of trauma patients transfused at least 1 U of PRBCs within 24 h of admission to a level 1 trauma center. The outcomes of interest were complicated sepsis and mortality. We compared the amount of older blood (>14 days storage) given to patients who did or did not develop the outcomes of interest using univariate and multivariate methods. A total of 820 patients were included. Patients who died (n = 117) received more units of older blood than those who lived (5 U inter quartile range {IQR}, 2-9 vs. 3 U IQR, 2-6; P< 0.001). Patients with complicated sepsis (n = 244) received a greater volume of older blood than those without complicated sepsis (6 U IQR, 2-10 vs. 3 U IQR, 1-5; P< 0.001). After adjusting for clinical factors, including the total amount of blood transfused, patients receiving greater than or equal to 7 U of older blood had a higher risk of complicated sepsis than patients receiving 1 or fewer units (odds ratio, 1.9; P= 0.03). The risk for complicated sepsis and death in trauma victims who are transfused blood is high. The amount of older blood transfused is associated with complicated sepsis. Although the best strategy to minimize the effects of allogeneic blood is to avoid unnecessary transfusions, it may be particularly important to avoid transfusing multiple units of older blood.

Severe burn injury results in a systemic inflammatory response that leads to increased capillary permeability and fluid leak into the interstitium. This global systemic capillary leak can be attributed, at least in part, to inflammatory mediators produced as a result of cellular injury. Plasma exchange has been used in the management of a number of illnesses with a significant inflammatory component, and, therefore, may have a role in the early management of burn injury. The purpose of this study was to review our institutional experience using plasma exchange in the management of severe burn injury. We performed a retrospective review of all patients receiving plasma exchange at our burn center between 2001 and 2005. Data collected included the following: burn size, presence of inhalation injury, resuscitation fluid received, urine output, lactate levels, base deficit levels, and hematocrit before and after the exchange procedure. A total of 37 patients underwent plasma exchange during the 5-year study period and seven patients underwent two plasma exchange treatments. Average TBSA burned was 48.6% (range 18-82) and 73% of patients sustained an inhalation injury. After plasma exchange, hourly fluid volume received significantly decreased (P< .05) and base deficit, lactate, and hematocrit levels significantly improved. Plasma exchange in the early resuscitation period was associated with decreased fluid administration, as well as increased urine output in the period during and immediately after the procedure. These data suggest that plasma exchange may provide a useful tool in the management of severe burn injury.

Approximately 50% of surgical site infections (SSI) after elective surgery occur after discharge. Adequate surveillance for these infections requires a mechanism for post-discharge follow up. The incidence of SSI after injury is as high as 30%. As post-discharge follow up in the trauma population is difficult, we set out to ascertain the incidence of post-discharge SSI in a cohort of high-risk trauma patients.

Allogeneic blood transfusions in surgical patients have been associated with an increased risk of infectious complications and organ dysfunction. Residual leukocytes contaminating units of packed red blood cells have been incriminated through the induction of anergy and/or a potentiated inflammatory response, leading to the possibility that leukoreduced red blood cell transfusion might mitigate these effects. We set out to evaluate the effect of leukoreduced red cell transfusion on the risk of infections complications in patients requiring transfusion following injury. We conducted a single-center, double-blinded randomized controlled trial of leukoreduced versus standard, nonleukoreduced red blood cell transfusions in injured patients receiving transfusion within 24 hrs of injury. The primary endpoint was infectious complications within 28 days of randomization. Secondary end points were multiple organ failure, length of stay, febrile episodes, and mortality. Two hundred sixty eight subjects were eligible for analysis. Rates of infectious complications were similar in subjects receiving leukoreduced transfusions (30%) or standard transfusions (36%) (RR, 0.84 0.55-1.3) and there was no statistically significant effect of leukoreduced blood transfusion on mortality RR, 1.20 (0.74-1.9), febrile episodes RR, 1.01 (0.89-1.2), or organ dysfunction scores (5.9 vs. 6.6; P= 0.29). Thus, pre-storage leukoreduction of allogeneic red blood cells had a small, but non-significant effect on the rate of infectious complication in this high-risk population requiring transfusion. There was no effect on the rates of febrile episodes, mortality, length of stay, or severity of organ dysfunction.

To increase transplantation access, particularly in living-donor renal transplantation, efforts have been made to overcome the barrier of ABO incompatibility. In adults, the most successful cases have involved renal transplantation. Although the overall goal of reducing antibodies against donor ABO before and after transplantation is a general principle, the protocols used to accomplish this goal vary. More well-designed, controlled clinical trials are needed to establish optimal peritransplantation management protocols. Incompatible liver transplantation still is viewed as a temporary measure until ABO-compatible transplantation can be performed. ABO-incompatible heart and lung transplantation in adults still is not performed intentionally. In children, particularly those with relatively immature immune systems, ABO-incompatible transplantation generally has more success. The immunologic mechanisms leading to successful transplantation are being elucidated. Accommodation is a process whereby the donor organ may participate in its own survival through a series of protective gene responses, possibly in response to low-level incompatible antibody (HLA and ABO). In infants, spontaneous, acquired B-cell tolerance seems to be a primary mechanism. Peritransplantation therapy might be tailored to invoke specific immune graft-sparing mechanisms. The stage is set to eliminate ABO as a barrier to solid-organ transplantation.

Microparticles are cell membrane derived vesicles that are released from apoptotic and activated cells. Recent studies have identified microparticles as the main source of circulating functionally active tissue factor, and increased numbers of tissue factor positive plasma microparticles have been associated with hypercoagulable states. Although the subject is controversial, some authors have suggested that red blood cell transfusions may be associated with increased risk of myocardial infarction in patients with acute coronary syndromes. This association could be due to prothrombotic elements in packed red blood cell units. We decided to characterize the microparticle content of packed red blood cell units, examining the microparticles for expression of annexin V, tissue factor, glycophorin-A, and CD41. We chose units near their expiration date because we hypothesized that the generation of microparticles would be time dependent and that units at this time would have the maximum number of microparticles. We isolated microparticles from 7 packed red blood cell units and from 4 samples of normal control plasma, and then used flow cytometry to count the number of annexin V positive microparticles with forward scatter characteristics that were similiar to 1 um beads. Next we used flow cytometry to examine these microparticles for expression of tissue factor, CD41, and Glycophorin A. We found that packed red blood cell units contain annexin V positive microparticles that segregate into two subsets- one group with a high level of annexin V expression and one group with a low level of annexin V expression. These two subsets appear to be distinct, with the high annexin V group expressing significantly more glycophorin-A (81.8% vs 8.9%, p<0.01) and more CD41 (71.4% vs 2.0%, p<0.01) while the low annexin V group showed more tissue factor reactivity (20.3% vs 4.8%, p<0.01). The significance of the tissue factor reactivity is not clear, and we plan to confirm the presence of active tissue factor in future samples with assays for tissue factor activity. We found that microparticles from normal plasma also appear to segregate into high annexin V and low annexin V subsets, although the percentage of microparticles with high annexin V expression was significantly lower than that found in packed red blood cell units (17.8% vs 26.0%, p<0.01). Relative to normal control plasma, packed red blood cells units appear to contain greater numbers of microparticles (3.05E+07/mL vs 4.64E+5/mL, p=0.07), greater numbers of annexin V positive microparticles (1.80E+7/mL vs 2.83E+5/mL, p=0.06), greater numbers of low annexin V microparticles (9.11E+6/mL vs 2.55E+05/mL, p=0.06), greater numbers of high annexin V microparticles (8.77E+6/mL vs 2.83E+4/mL, p=0.06), and a higher level of microparticles with tissue factor reactivity (2.06E+6/mL vs 9.66E+3/mL, p=0.06). We plan to run additional samples to see if these differences will reach statistical significance. We also examined one leukoreduced packed red blood cell unit and found it to have lower levels of microparticles, lower levels of high annexin V microparticles, and lower levels of tissue factor expression as compared to non-leukoreduced units. We plan to run additional leukoreduced units to see if these differences are significant. Overall our study has partially characterized the microparticle content of packed red blood cell units, which to our knowledge has not been reported in the literature.