Hemolysis in stored red blood cell concentrates: modulation by haptoglobin or ulinastatin, a protease inhibitor

Contribution of Various Types of Transfusion to Acute and Delayed Intracerebral Hemorrhage Injury

Intracerebral hemorrhage (ICH) is the second most prevalent type of stroke, after ischemic stroke, and has exceptionally high morbidity and mortality rates. After spontaneous ICH, one primary goal is to restrict hematoma expansion, and the second is to limit brain edema and secondary injury. Various types of transfusion therapies have been studied as treatment options to alleviate the adverse effects of ICH etiopathology. The objective of this work is to review transfusions with platelets, fresh frozen plasma (FFP), prothrombin complex concentrate (PCC), and red blood cells (RBCs) in patients with ICH. Furthermore, tranexamic acid infusion studies have been included due to its connection to ICH and hematoma expansion. As stated, the first line of therapy is limiting bleeding in the brain and hematoma expansion. Platelet transfusion is used to promote recovery and mitigate brain damage, notably in patients with severe thrombocytopenia. Additionally, tranexamic acid infusion, FFP, and PCC transfusion have been shown to affect hematoma expansion rate and volume. Although there is limited available research, RBC transfusions have been shown to cause higher tissue oxygenation and lower mortality, notably after brain edema, increases in intracranial pressure, and hypoxia. However, these types of transfusion have varied results depending on the patient, hemostasis status/blood thinner, hemolysis, anemia, and complications, among other variables. Inconsistencies in published results on various transfusion therapies led us to review the data and discuss issues that need to be considered when establishing future guidelines for patients with ICH.

Ulinastatin reduces postoperative bleeding and red blood cell transfusion in patients undergoing cardiac surgery: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

Ulinastatin is a type of glycoprotein and a nonspecific wide-spectrum protease inhibitor like antifibrinolytic agent aprotinin. Whether Ulinastatin has similar beneficial effects on blood conservation in cardiac surgical patients as aprotinin remains undetermined. Therefore, a systematic review and meta-analysis were performed to evaluate the effects of Ulinastatin on perioperative bleeding and transfusion in patients who underwent cardiac surgery.

METHODS

Electronic databases were searched to identify all clinical trials comparing Ulinastatin with placebo/blank on postoperative bleeding and transfusion in patients undergoing cardiac surgery. Primary outcomes included perioperative blood loss, blood transfusion, postoperative re-exploration for bleeding. Secondary outcomes include perioperative hemoglobin level, platelet counts and functions, coagulation tests, inflammatory cytokines level, and so on. For continuous variables, treatment effects were calculated as weighted mean difference (WMD) and 95% confidential interval (CI). For dichotomous data, treatment effects were calculated as odds ratio and 95% CI. Statistical significance was defined as P < .05.

RESULTS

Our search yielded 21 studies including 1310 patients, and 617 patients were allocated into Ulinastatin group and 693 into Control (placebo/blank) group. There was no significant difference in intraoperative bleeding volume, postoperative re-exploration for bleeding incidence, intraoperative red blood cell transfusion units, postoperative fresh frozen plasma transfusion volumes and platelet concentrates transfusion units between the 2 groups (all P > .05). Ulinastatin reduces postoperative bleeding (WMD = -0.73, 95% CI: -1.17 to -0.28, P = .001) and red blood cell (RBC) transfusion (WMD = -0.70, 95% CI: -1.26 to -0.14, P = .01), inhibits hyperfibrinolysis as manifested by lower level of postoperative D-dimer (WMD = -0.87, 95% CI: -1.34 to -0.39, P = .0003).

CONCLUSION

This meta-analysis has found some evidence showing that Ulinastatin reduces postoperative bleeding and RBC transfusion in patients undergoing cardiac surgery. However, these findings should be interpreted rigorously. Further well-conducted trials are required to assess the blood-saving effects and mechanisms of Ulinastatin.

Circuit oxygenator contributes to extracorporeal membrane oxygenation-induced hemolysis

Hemolysis can occur as a consequence of extracorporeal membrane oxygenation (ECMO) and is associated with increased mortality and morbidity. Shear stress generated by flow through the circuit and oxygenator is believed to cause ECMO-induced hemolysis. We hypothesize that either a smaller dimension oxygenator or an in-line hemofilter will increase ECMO-associated hemolysis. Circuits were configured with a Quadrox-D Adult oxygenator (surface area 1.8 m), Quadrox-iD Pediatric oxygenator (surface area 0.8 m), or Quadrox-D Adult oxygenator with an in-line hemofilter (N = 4) and ran for 6 hours. Samples were collected hourly from the ECMO circuit and a time-based hemolysis control. Plasma hemoglobin levels were assayed. Circuit-induced hemolysis at each time point was defined as the change in plasma hemoglobin standardized to the time-based hemolysis control. Plasma hemoglobin increased with the use of the smaller dimension pediatric oxygenator as compared with the adult oxygenator when controlling for ECMO run time (p = 0.02). Furthermore, there was a greater pressure gradient with the smaller dimension pediatric oxygenator (p < 0.05). Plasma hemoglobin did not change with the addition of the in-line hemofilter. The use of a smaller dimension pediatric oxygenator resulted in greater hemolysis and a higher pressure gradient. This may indicate that the increased shear forces augment ECMO-induced hemolysis.

Ulinastatin Protects against Acute Kidney Injury in Infant Piglets Model Undergoing Surgery on Hypothermic Low-Flow Cardiopulmonary Bypass

Objective

Infants are more vulnerable to kidney injuries induced by inflammatory response syndrome and ischemia-reperfusion injury following cardiopulmonary bypass especially with prolonged hypothermic low-flow (HLF). This study aims to evaluate the protective role of ulinastatin, an anti-inflammatory agent, against acute kidney injuries in infant piglets model undergoing surgery on HLF cardiopulmonary bypass.

Methods

Eighteen general-type infant piglets were randomly separated into the ulinastatin group (Group U, n = 6), the control group (Group C, n = 6), and the sham operation group (Group S, n = 6), and anaesthetized. The groups U and C received following experimental procedure: median thoracotomy, routine CPB and HLF, and finally weaned from CPB. The group S only underwent sham median thoracotomy. Ulinastatin at a dose of 5,000 units/kg body weight and a certain volume of saline were administrated to animals of the groups U and C at the beginning of CPB and at aortic declamping, respectively. Venous blood samples were collected at 3 different time points: after anesthesia induction in all experimental groups, 5 minutes, and 120 minutes after CPB in the Groups U and C. Markers for inflammation and acute kidney injury were tested in the collected plasma. N-acetyl-β-D-glucosaminidase (NAG) from urine, markers of oxidative stress injury and TUNEL-positive cells in kidney tissues were also detected.

Results

The expressions of plasma inflammatory markers and acute kidney injury markers increased both in Group U and Group C at 5 min and 120 min after CPB. Also, numbers of TUNEL-positive cells and oxidative stress markers in kidney rose in both groups. At the time point of 120-min after CPB, compared with the Group C, some plasma inflammatory and acute kidney injury markers as well as TUNEL-positive cells and oxidative stress markers in kidney were significantly reduced in the Group U. Histologic analyses showed that HLF promoted acute tubular necrosis and dilatation.

Conclusions

HLF cardiopulmonary bypass surgery could intensify systemic inflammatory responses and oxidative stress on infant piglets, thus causing acute kidney injury. Ulinastatin might reduce such inflammatory response and oxidative stress and the extent of kidney injury.

Transfusion begets anemia: the effect of aged blood on hematopoiesis

BACKGROUND

Following trauma, transfusion of aged stored blood is often necessary yet associated with increased morbidity and mortality. Despite blood replacement, many patients have a prolonged anemia requiring further transfusions. The effects of aged blood on bone marrow (BM) hematopoiesis have not been studied, and we hypothesized that stored blood suppresses BM function.

METHODS

Blood from Sprague-Dawley rats was stored for 1, 14, or 28 days with the industry preservative citrate-phosphate-dextrose-adenine-1 (CPDA-1). For in vitro studies, 5% supernatant was incubated with normal rat BM and cultured for erythroid (CFU-E) and granulocyte-macrophage (CFU-GM) colony-forming units. Data were compared with cultures of BM alone, 5% control plasma (negative control), and 12% CPDA-1. For in vivo studies, rats were transfused with stored supernatants (5% estimated blood volume (EBV) over 30 minutes). BM from each recipient was cultured for CFU-E and CFU-GM at 3 hours after transfusion. Data were compared with cultures of BM alone. Difference between groups determined by analysis of variance and Tukey's multiple comparison test.

RESULTS

In vitro exposure to CPDA-1, control plasma, or 1-day supernatant (D1) had no effect on BM growth compared with BM alone. In vitro exposure to 14-day (D14) and 28-day (D28) supernatant significantly suppressed CFU-E by 60% and CFU-GM growth by 71% (both p < 0.05) compared with D1 or medial alone. There were no differences between D14 and D28. In vivo exposure to D14 reduced BM CFU-E and CFU-GM growth by 55% (both p < 0.05) compared with D1 supernatant.

CONCLUSION

Plasma from aged blood adversely affects CFU-E and CFU-GM growth in rats. The effect is not mediated by CPDA-1. Transfusion of aged stored blood may contribute to BM dysfunction in critically ill patients, resulting in persistent anemia and the need for further transfusion. This BM dysfunction may also partly explain the observed increased susceptibility to infection.

Evaluation of a red cell leukofilter performance and effect of buffy coat removal on filtration efficiency and post filtration storage

Prestorage leukoreduction of red cells is effective in reducing the incidence of HLA alloimmunization and improving the quality of stored packed red blood cells (PRBC). This study was conducted to evaluate the effectiveness of Imugard III-RC 4P in removing the leukocyte from packed red cells and the storage effects thereafter. The effects of buffy coat removal on the efficiency of leukofiltration, storage parameters of leukofiltered packed red blood cells and feasibility of prestorage leukofiltration were also assessed. Sixteen units each of buffy coat-depleted (LP) and nondepleted (NLP) PRBC were taken. Every unit was divided into two equal halves, one leukofiltered and other, non-leukofiltered. Cell counts, volume, hematocrit and hemoglobin were measured before and after filtration. Levels of K(+), lactate dehydrogenase (LDH) and hemolysis were assessed in all the units weekly, post leukofiltration. Post leukofiltration, red cell and volume loss was within the specified limit in all the units. Residual leukocytes were significantly lesser in LP- PRBC compared to NLPPRBC. K(+), LDH and hemolysis were significantly elevated in NLP- PRBC. Leukofiltered PRBC showed lesser elevation of K(+), LDH and hemolysis towards the end of the storage period as compared to their unfiltered counterparts. Leukofilter is capable of performing ~4 log reduction. Buffy coat removal prior to filtration improves the efficiency of leukofilter and aids in improving the storage of red cells in terms of hemolysis.

Red blood cell transfusion in the neurological ICU

Red blood cell transfusion (RBCT) is a common therapy used in the intensive care unit to treat anemia. However, due to deleterious side effects and questionable efficacy, the clinical benefit of RBCT in patients who are not actively bleeding is unclear. The results of randomized controlled trials suggest there is no benefit to a liberal transfusion practice in general critical care populations. Whether the results of these trials are applicable to brain injured patients is unknown, as patients with primary neurological injury were excluded. This article reviews the efficacy and complications of RBCT, as well as the relationship between RBCT and its outcome in both the general intensive care unit and neurologically critically ill populations.

The optimal hematocrit

Nearly 15 million units of packed red blood cells and whole blood are transfused annually in the United States alone. Until recently, the major risks from blood transfusion were thought to be transmission of viral infections, and overall, blood transfusion was believed by most providers to be safe. A safe hemoglobin threshold above which red cell transfusion is clearly unnecessary has not been established. This article addresses the numerous problems that surround the use and consequences of blood transfusion, such as hemoglobin and hematocrit levels, oxygenation, storage time, immunomodulation, infection, and anemia. The relevant literature is comprehensively reviewed.

Complications of massive transfusion

Massive transfusion (MT) is a lifesaving treatment of hemorrhagic shock, but can be associated with significant complications. The lethal triad of acidosis, hypothermia, and coagulopathy associated with MT is associated with a high mortality rate. Other complications include hypothermia, acid/base derangements, electrolyte abnormalities (hypocalcemia, hypomagnesemia, hypokalemia, hyperkalemia), citrate toxicity, and transfusion-associated acute lung injury. Blood transfusion in trauma, surgery, and critical care has been identified as an independent predictor of multiple organ failure, systemic inflammatory response syndrome, increased infection, and increased mortality in multiple studies. Once definitive control of hemorrhage has been established, a restrictive approach to blood transfusion should be implemented to minimize further complications.

Changes in polymorphonuclear leukocyte elastase concentrations and hemolysis parameters in patients transfused with different blood preparations, and in the blood preparations themselves

PURPOSE

Massive blood transfusion induces hemolysis and increases polymorphonuclear leukocyte elastase (PMNE) concentration. The purpose of this study was to compare hemolysis and PMNE concentrations in massive blood transfusions with three different preparations.

METHODS

In an in vitro study, eight 2-day-old packs of concentrated red blood cells in mannitol, adenine, glucose, phosphate, and citrate solution (MAP-CRC); concentrated red blood cells in citrate, phosphate, and glucose solution (CPD-CRC); or whole blood in citrate, phosphate, and glucose solution (WB) were stored at 4 degrees C. Supernatant concentrations of total and free hemoglobin, total haptoglobin, and PMNE were measured. In an in vivo study, 24 surgical patients with expected bleeding exceeding 3000 ml were transfused with CPD-CRC or MAP-CRC with fresh frozen plasma, or with WB. Platelet count, prothrombin time, activated partial thromboplastin time, serum total and free hemoglobin, and total haptoglobin and plasma PMNE concentrations were measured.

RESULTS

In the in vitro study, total and free hemoglobin concentrations were significantly higher in CPD-CRC than in the other two preparations. Total haptoglobin concentration was highest in the order of WB > MAP-CRC > CPD-CRC. The PMNE concentration was significantly higher in WB than in the other two preparations. In the in vivo study, at 3000-ml transfusion, total and free hemoglobin concentrations were significantly lower and activated partial thromboplastin time was longer in the patients with MAP-CRC compared with values in the other two groups. The PMNE concentration was significantly higher in the order of the WB > CPD-CRC > MAP-CRC groups.

CONCLUSION

During the storage of MAP-CRC, CPD-CRC, and WB, CPD-CRC had the greatest hemolysis and WB had the highest concentration of PMNE. Patients who received massive blood transfusion of MAP-CRC had the least hemolysis and the lowest concentration of PMNE.

Electrostatic field can preserve red blood cells in stored blood preparations

PURPOSE

During the storage of red blood cell concentrates (CRCs), red blood cells are progressively destroyed and free hemoglobin and potassium concentrations increase. In this study, we focused on an electrostatic field that maintains food freshness without freezing, even at less than the freezing point. We hypothesized that the storage of CRCs under an electrostatic field could keep red blood cells in better condition than conventional storage.

METHODS

Each of 15 packs of 2-day-old CRCs, preserved in MAP (mannitol, adenine, glucose, phosphate, and citrate) solution (MAP-CRC) was divided into 4 smaller equal-size packs and stored at 4 degrees C in a newly developed refrigerator that can generate an electrostatic field. Each group was exposed to a 0-, 500-, 1500-, or 3000-volt (V) electric field for 30 days. Concentrations of free hemoglobin, total haptoglobin, sodium (Na), and potassium (K), and the pH, were measured in the supernatant.

RESULTS

Haptoglobin was not detected. The Na concentration decreased with time but was significantly lower in the 0-V than in the 500-, 1500-, and 3000-V groups. K and free hemoglobin concentrations increased with time, with significantly higher values in the 0-V than in the 500-, 1500-, and 3000-V groups. The pH decreased in the 500-, 1500-, and 3000-V groups, while it did not change in the 0-V group. The pH decrease was smaller in the 500-V than in the 1500- and 3000-V groups.

CONCLUSION

Storing MAP-CRC in an electrostatic field of 500 to 3000 V could decrease hemolysis in the preparation. Considering the lower pH decrease, 500 V might be the field of choice.

Current status of blood component therapy in surgical critical care

PURPOSE OF REVIEW

The use of blood component therapy, with transfusion of red cells, plasma, and platelets, is common in critical care. New evidence has emerged documenting the risks associated and lack of efficacy or improvement in clinical outcome with blood transfusion for the treatment of anemia in critically ill patients who are hemodynamically stable.

RECENT FINDINGS

The safety of a restrictive transfusion strategy (transfuse only if hemoglobin < 7 g/dL) was reported in 1999. Despite compelling evidence from this prospective randomized clinical trial, clinicians have not substantially changed practice regarding blood transfusion in critical care. The recently published CRIT trial reported that the mean pre-transfusion hemoglobin was 8.6 g/dL in this large multicenter trial that examined transfusion practices in critical care in the US. Furthermore, only 19% of hospitals had an institutional blood transfusion protocol. The Surviving Sepsis Campaign guidelines have also recommended blood transfusion only when hemoglobin falls to 7.0 g/dL, following resolution of tissue hypoperfusion and in the absence of significant coronary artery disease or acute hemorrhage. We have an increased understanding of the pathophysiology of the anemia associated with critical care, related to the inflammatory response, downregulation of erythropoietin, and lack of iron availability due to macrophage sequestration. Clinical trials are underway to confirm the efficacy of recombinant erythropoietin in the treatment of critically ill patients with anemia.

SUMMARY

Current data regarding blood transfusion thresholds and risks of blood transfusion have not as yet significantly altered practice patterns. Efforts to reduce blood transfusion rates in critically ill patients are required. These strategies will require education, unit and institutional protocols, and reduction of phlebotomy for diagnostic laboratory testing in the intensive care unit. Further investigations regarding anemia in critical care and new treatment and prevention strategies are required.

Prestorage leukoreduction and low-temperature filtration reduce hemolysis of stored red cell concentrates

BACKGROUND

Universal prestorage leukoreduction in Canada created the perception that stored red cells (RBCs) are more hemolyzed than their unfiltered predecessors. A pool-split design tested the effects of leukoreduction on hemolysis of stored RBCs.

STUDY DESIGN AND METHODS

Two ABO-matched units were pooled, divided, and then processed into leukoreduced (LR) and nonleukoreduced (NLR) units with the Pall LT-WB or RC-PL systems and sampled during standard processing and storage for testing of sterility, counts, hemolysis, and osmotic fragility.

RESULTS

Room temperature (RT) filtration of 10 pairs of LT-WB-LR and -NLR units showed significantly different percentage of hemolysis (0.39%) and osmotic fragility (0.643%) at 42 days. Cold-stored and -filtered units (2 days at 4 degrees C before processing) were less hemolyzed, but showed a similar proportional decrease of hemolysis in LR units (0.13% vs. 0.25% at 42 days). RBCs from RC-PL systems showed the lowest hemolysis although there was a filtration effect (0.05% vs. 0.12%, 42 days). Osmotic fragility paralleled hemolysis. Segment samples gave inaccurate results. Two-day prefiltration cold storage reduced hemolysis from 0.36 to 0.07 percent (42 days, p < 0.001). RT-LR hemolysis became significantly higher by Day 10 and 4 degrees C LR by Day 12. NLR units showed hemolysis by Day 7. LR units filtered cold were less hemolyzed (p < 0.05) than RT-LR but osmotic fragility was unchanged.

CONCLUSIONS

LR-RBCs prepared by any of three methods (LT-WB, RT or cold; RC-PL), filtered at 4 degrees C, were less hemolyzed during storage than nonfiltered concentrates: 4 degrees C leukoreduction is beneficial for RBCs and does not cause hemolysis or enhance fragility.

Efficacy of red blood cell transfusion in the critically ill

This article has evaluated the published data regarding the efficacy of RBC transfusions in the critically ill. Taken together, these studies generally support conservative RBC transfusion strategies in critical care to reduce the risk of transfusion-related adverse effects. The TRICC trial has established the safety ofa restrictive transfusion strategy, suggesting that physicians could minimize exposure to allogeneic RBCs by lowering their transfusion threshold. Further research will add to the generalizability of this study and explore the possible mechanism to explain why RBC transfusions do not improve outcomes in the critically ill. Additional studies will be necessary to determine the effects of RBC storage time and the presence of allogeneic leukocytes in allogeneic RBC. The following conclusions are evident: 1. RBC transfusion does not improve tissue oxygen consumption consistently in critically ill patients, either globally or at the level of the micro-circulation. 2. RBC transfusion is not associated with improvements in clinical outcome in the critically ill and may result in worse outcomes in some patients. 3. Specific factors that identify patients who will improve from RBC transfusion are difficult to identify. 4. Lack of efficacy of RBC transfusion likely is related to storage time, increased endothelial adherence of stored RBCs, nitric oxide binding by free hemoglobin in stored blood, donor leukocytes, host inflammatory response, and reduced red cell deformability.