The effects of cryopreserved red blood cell transfusion on tissue oxygenation in obese trauma patients.

BACKGROUND: Low tissue oxygenation (StO2) is associated with poor outcomes in obese trauma patients. A novel treatment could be the transfusion of cryopreserved packed red blood cells (CPRBCs), which the in vitro biochemical profile favors red blood cell (RBC) function. We hypothesized that CPRBC transfusion improves StO2 in obese trauma patients. METHODS: Two hundred forty-three trauma patients at five Level I trauma centers who required RBC transfusion were randomized to receive one to two units of liquid packed RBCs (LPRBCs) or CPRBCs. Demographics, injury severity, StO2, outcomes, and biomarkers of RBC function were compared in nonobese (body mass index [BMI] < 30) and obese (BMI ≥ 30) patients. StO2 was also compared between obese patients with BMI of 30 to 34.9 and BMI ≥ 35. StO2 was normalized and expressed as % change after RBC transfusion. A p value less than 0.05 indicated significance. RESULTS: Patients with BMI less than 30 (n = 141) and BMI of 30 or greater (n = 102) had similar Injury Severity Score, Glasgow Coma Scale, and baseline StO2. Plasma levels of free hemoglobin, an index of RBC lysis, were lower in obese patients after CPRBC (125 [72-259] µg/mL) versus LPRBC transfusion (230 [178-388] µg/mL; p < 0.05). StO2 was similar in nonobese patients regardless of transfusion type, but improved in obese patients who received CPRBCs (104 ± 1%) versus LPRPCs (99 ± 1%, p < 0.05; 8 hours after transfusion). Subanalysis showed improved StO2 after CPRBC transfusion was specific to BMI of 35 or greater, starting 5 hours after transfusion (p < 0.05 vs. LPRBCs). CPRBCs did not improve clinical outcomes in either group. CONCLUSION: CPRBC transfusion is associated with increased StO2 and lower free hemoglobin levels in obese trauma patients, but did not improve clinical outcomes. Future studies are needed to determine if CPRBC transfusion in obese patients attenuates hemolysis to improve StO2. LEVEL OF EVIDENCE: Therapeutic, level IV.

Transfusion of cryopreserved packed red blood cells is safe and effective after trauma: a prospective randomized trial.

OBJECTIVES: To determine the safety and efficacy of cryopreserved packed red blood cell (CPRBC) transfusion in trauma patients. BACKGROUND: Liquid packed red blood cells (LPRBCs) have an abbreviated shelf-life and worsening storage lesion with age. CPRBCs are frozen 2 to 6 days after donation, stored up to 10 years, and are available for 14 days after thawing and washing. CPRBCs can be utilized in diverse settings, but the effect on clinical outcomes is unknown. METHODS: We performed a prospective, randomized, double-blind study at 5 level 1 trauma centers. Stable trauma patients requiring transfusion were randomized to young LPRBCs (≤14 storage days), old LPRBCs (>14 storage days), or CPRBCs. Tissue oxygenation (StO2), biochemical and inflammatory mediators were measured, and clinical outcomes were determined. RESULTS: Two hundred fifty-six patients with well-matched injury severity and demographics (P > 0.2) were randomized (84 young, 86 old, and 86 CPRBCs). Pretransfusion and final hematocrits were similar (P > 0.68). Patients in all groups received the same number of units postrandomization (2 [1-4]; P > 0.05). There was no difference in the change in tissue oxygenation between groups. CPRBCs contained less α2-macrogobulin, haptoglobin, C-reactive protein, and serum amyloid P (P < 0.001). Organ failure, infection rate, and mortality did not differ between groups (P > 0.2). CONCLUSIONS: Transfusion of CPRBCs is as safe and effective as transfusion of young and old LPRBCs and provides a mechanism to deliver PRBCs in a wide variety of settings.

Cryopreserved red blood cells are superior to standard liquid red blood cells.

BACKGROUND: Liquid preserved packed red blood cell (LPRBC) transfusions are used to treat anemia and increase end-organ perfusion. Throughout their storage duration, LPRBCs undergo biochemical and structural changes collectively known as the storage lesion. These changes adversely affect perfusion and oxygen off-loading. Cryopreserved RBCs (CPRBC) can be stored for up to 10 years and potentially minimize the associated storage lesion. We hypothesized that CPRBCs maintain a superior biochemical profile compared with LPRBCs. METHODS: This was a prospective, randomized, double-blinded study. Adult trauma patients with an Injury Severity Score (ISS) greater than 4 and an anticipated 1-U to 2-U transfusion of PRBCs were eligible. Enrolled patients were randomized to receive either CPRBCs or LPRBCs. Serum proteins (haptoglobin, serum amyloid P, and C-reactive protein), proinflammatory and anti-inflammatory cytokines, d-dimer, nitric oxide, and 2,3-DPG concentrations were analyzed. Mann-Whitney U-test and Wilcoxon rank sum test were used to assess significance (p < 0.05). RESULTS: Fifty-seven patients were enrolled (CPRBC, n = 22; LPRBC, n = 35). The LPRBC group's final interleukin 8, tumor necrosis factor α, and d-dimer concentrations were elevated compared with their pretransfusion values (p < 0.05). After the second transfused units, 2,3-DPG was higher in the patients receiving CPRBCs (p < 0.05); this difference persisted throughout the study. Finally, serum protein concentrations were decreased in the transfused CPRBC units compared with LPRBC (p < 0.01). CONCLUSION: CPRBC transfusions have a superior biochemical profile: an absent inflammatory response, attenuated fibrinolytic state, and increased 2,3-DPG. A blood banking system using both storage techniques will offer the highest-quality products to critically injured patients virtually independent of periodic changes in donor availability and transfusion needs. LEVEL OF EVIDENCE: Therapeutic study, level II.

Hyperosmolar reconstituted lyophilized plasma is an effective low-volume hemostatic resuscitation fluid for trauma.

BACKGROUND: We performed this study to optimize reconstituted lyophilized plasma (LP) into a minimal volume fluid that provides effective hemostatic resuscitation for trauma while minimizing logistical limitations. METHODS: We performed a prospective, blinded animal study. Plasma was lyophilized following whole blood collection from anesthetized swine. The minimal volume needed for reconstitution was determined, and this solution was evaluated for safe infusion into the swine. Reconstituted LP was analyzed for electrolyte content, osmolarity, and coagulation factor activity. Twenty swine were anesthetized and subjected to a validated model of polytrauma and hemorrhagic shock (including a Grade V liver injury), then randomized to resuscitation with LP reconstituted to either 100% of the original plasma volume (100%LP) or the minimal volume LP fluid. Physiologic data were monitored, and blood loss and hematocrit were measured. Coagulation status was evaluated using thrombelastography. RESULTS: The minimal volume of reconstituted LP safe for infusion in swine was 50% of the original plasma volume (50%LP). The 50%LP had higher electrolyte concentrations, osmolarity, and increased coagulation factor activity levels by volume compared with 100%LP (p < 0.05). Blood loss, hematocrit, mean arterial pressure, and heart rate did not differ between animals receiving 100%LP (n = 10) or 50%LP (n = 10) at any time point (p > 0.05). International normalized ratio and thrombelastography parameters were not different between groups (R time, α angle, or maximal amplitude, p > 0.05). CONCLUSION: Resuscitation with 50%LP fluid was well tolerated and equally effective compared with 100%LP, with respect to physiologic and hemostatic properties. The smaller volume of fluid necessary to reconstitute hypertonic LP makes it logistically superior to 100%LP for first responders and may reduce adverse effects of large-volume resuscitation.

Cryopreserved deglycerolized blood is safe and achieves superior tissue oxygenation compared with refrigerated red blood cells: a prospective randomized pilot study.

BACKGROUND: During preservation, donated liquid red blood cells (RBCs) experience multiple functional and structural changes known as the storage lesion. Increased RBC age is associated with increased infection rates, organ failure, and mortality. METHODS: This prospective, randomized, double-blinded pilot study enrolled stable trauma patients who required RBC transfusion. Patients were randomly assigned to receive standard or cryopreserved RBCs. Continuous tissue oxygenation (StO2) monitoring was performed during the peritransfusion period. Hematocrit and thrombelastography before and after transfusion were evaluated. Patients were monitored for transfusion reactions and clinical outcomes. RESULTS: Fifty-seven patients were randomized, and groups were well matched for demographics and Injury Severity Score (ISS). No statistically significant differences were noted in hematocrit change, thrombelastography parameters, transfusion reactions, or clinical outcomes. StO2 was found to be higher in the cryopreserved group. CONCLUSION: Cryopreserved RBCs are equally safe and efficacious to refrigerated RBCs. This storage technique extends the life span of RBCs to 10 years, potentially preserving a precious resource and preventing the storage lesion. StO2 was superior in patients receiving cryopreserved RBCs. This finding has the potential to drive a paradigm shift in transfusion practices. LEVEL OF EVIDENCE: Therapeutic study, level II.