Allogeneic Red Cell Research Articles

An animal model for delayed hemolytic transfusion reactions1

Delayed hemolytic transfusion reactions (DHTRs) are a well-known complication of transfusion that may be defined as immune-mediated hemolysis of allogeneic donor red cells that occurs approximately 3 to 5 days after transfusion. In general, DHTRs occur in patients who have been alloimmunized previously, but the antibody titers have fallen below serologically detectable levels. Transfusion of seemingly compatible blood and exposure to the putative alloantigen results in an anamnestic immune response that may lead to in vivo accelerated destruction of donor red cells. Symptoms may include a drop in hemoglobin and hematocrit, fever, jaundice, and renal insufficiency. More recent studies have shown that there is a subset of cases called delayed serologic transfusion reactions (DSTRs) when there are serologic findings consistent with DHTRs but no clinical evidence of hemolysis. In both DHTRs and DSTRs, direct antiglobulin tests are often persistently positive long after the transfused donor red cells should have been removed from the circulation. Because the studies required to investigate the immunologic and clinical aspects of these reactions are precluded in humans, we developed an animal model for the study of DHTRs and DSTRs. Our article provides a comprehensive review of DHTRs and DSTRs, the role of complement and cytokines in these reactions, and the phenomenon of bystander hemolysis. We describe our studies using the rabbit as a model for the study of DHTRs and bystander hemolysis.

New technologies for the inactivation of infectious pathogens in cellular blood components and the development of platelet substitutes

Despite the increased safety of blood components, achieved through improved donor selection and testing, transfusion recipients remain at risk of transfusion-associated diseases. Transfusion of cellular blood components has been implicated in transmission of viral, bacterial and protozoan diseases.1 While it is commonly recognized that hepatitis B virus (HBV), hepatitis C virus (HCV), cytomegalovirus (CMV), and retroviruses, such as human immunodeficiency virus (HIV) and the human lymphotrophic viruses (HTLV), can be transmitted through cellular components, other pathogens are emerging as potentially significant transfusion-associated infectious agents. For example, transmission of protozoan infections due to trypanosomes2 andBabesia have been reported.5 In addition to viral and protozoan infectious agents, cases of bacterial contamination of platelet and red cell concentrates continue to be reported 6,7 and may be an under-reported transfusion complication.8 More importantly, new infectious agents continue to enter the donor population, and there is an inherent time delay before the new pathogens are definitively identified and new tests implemented in order to maintain consistent safety of the blood supply. The paradigm for this problem is the HIV pandemic.During the past decade a number of methods for inactivating infectious pathogens in platelet concentrates have been investigated as a strategy to improve the safety of platelet transfusion therapy. One method of treating platelet concentrates to inactive pathogens has now reached the advanced clinical trial phase in the United States and Europe. Similar efforts with a new class of compounds are underway for red cell concentrates, and two of these are in early phase trials. In addition to studies with allogeneic platelets and red cells, a number of laboratories have described methods for developing platelet substitutes or modified platelets to avoid the use of traditional platelet concentrates as a means to improve safety.

Post-transfusion thrombocytopenia in recipients with anti-HLA antibody

Allogeneic red cell transfusion produced a significant decrease in the platelet counts of recipients who possessed anti-HLA antibodies.

Transfusions in patients undergoing cardiac surgery with autologous blood.

Determinants of allogeneic blood use in cardiac surgery include preoperative factors such as female sex, age, body weight, hematocrit and red cell volume. We verified if these variables also predicted the need for allogeneic transfusions when autologous blood is predonated. Demographic and intraoperative variables, hemoglobin concentrations and transfusion requirements in patients undergoing cardiopulmonary bypass with autologous blood predonation were reviewed. Multivariate logistic regression and RECPAM tree-growing analyses were applied to identify the preoperative predictors of allogeneic transfusion in these patients. Data from 230 patients included in our autologous blood program between 1995 and 1998 were analysed. Patients undergoing complex/reoperative surgical procedures and patients over age 64yr with a low red cell volume (<2070ml) undergoing simple procedures were more likely to require allogeneic red cells. Younger patients with a low red cell volume undergoing simple procedures carried an intermediate risk. Allogeneic transfusion was avoided in 95% of patients undergoing simple procedures when red cell volume > or = 2070ml. In our institution, complex/reoperative surgery, low red cell volume and increased age are the main factors associated with the need for allogeneic red cell transfusion despite autologous blood predonation. Knowledge of the factors that limit the effectiveness of predonation with respect to allogeneic blood exposure should help clinicians decide which cardiac surgical patients should be included in autologous blood programs.

Incidence and risk factors for allogenic blood transfusion during major joint replacement using an integrated autotransfusion regimen. The Rizzoli Study Group on Orthopaedic Anaesthesia.

The efficacy of an integrated autotransfusion regimen, including pre-donation and perioperative salvage of autologous blood, was prospectively evaluated in 2884 patients undergoing total hip (n = 2016) or knee arthroplasty (n = 480), and hip revision (n = 388) with either balanced general, regional, or integrated epidural/general anaesthesia. Allogenic concentrated red blood cells were transfused in the presence of symptomatic anaemia or when haemoglobin concentration was < 6 g dL-1 (10 g dL-1 in patients affected by cerebrovascular or coronary artery disease) after all salvaged and pre-donated autologous blood had been transfused. A total of 278 patients (9.6%) received allogenic blood. Risk factors for allogenic blood transfusion were: preoperative haemoglobin concentration < 10 g dL-1 (after autologous blood pre-donations) (Odds ratio: 8.7; 95% CI: 6.5-16.8; P = 0.004), hip revision versus hip or knee arthroplasty (Odds ratio: 5.8; 95% CI: 3.9-8.5; P = 0. 0001) and inability in obtaining the number of pre-donations required by the Maximum Surgery Blood Order on Schedule (Odds ratio: 3.4; 95% CI: 2.7-4.1; P = 0.0001). The incidence of perioperative complications, including wound infection and haematoma, as well as myocardial ischaemia, respiratory failure and thromboembolic complications, was higher in those patients requiring allogenic blood transfusion (29.8%) than that observed in patients receiving only autologous blood (6.6%) (P = 0.0005); while the mean time duration from surgical procedure to patient discharge from the orthopaedic ward was shorter in those patients not receiving allogenic blood transfusion (12 days; 25-75th percentiles: 8-14 days) than in those patients who required perioperative transfusion with allogenic blood (15 days; 25-75th percentiles: 10-17 days) (P = 0.0005). In conclusion, this prospective study highlighted the clinical relevance of applying an extensive and integrated autotransfusion regimen in order to reduce allogenic blood transfusion and associated complications in patients undergoing major joint replacement.

Transfusion Thresholds in Common Elective Surgical Procedures in Finland

Background and Objectives: Transfusion practices and thresholds in common elective surgical procedures were investigated in a nationwide multicenter survey in Finland. Materials and Methods: The records of 764 total hip replacement (THR), 397 total knee replacement (TKR) and 343 transurethral resection of the prostate (TURP) patients were reviewed by four anesthesiologists. Results: The allogeneic red cell (RBC) transfusion rates in THR, TKR and TURP operations were 92, 84 and 18%, respectively. In THR and TKR, 74% of patients who lost 20% or less of their blood volume during hospitalization were transfused with RBCs. Postoperatively, the median pretransfusion hemoglobin values were 9.6 g/dl in orthopedic operations and 10.7 g/dl in TURP. In some hospitals, the median transfusion threshold in TURP patients was as high as 11.2 g/dl. Conclusion: The transfusion thresholds in all operations were liberal compared to recent international recommendations. Inappropriate thresholds were reflected in the high transfusion rates. This study accentuates the need for continuous discussion and educational measures to find optimal indications for transfusion in surgery, and to rationalize the transfusion policy in Finland.

Allogeneic Red Blood Cell Transfusion Is an Independent Risk Factor for the Development of Postoperative Bacterial Infection

Abstract Background and Objectives: Allogeneic red blood cell transfusions may exert immunomodulatory effects in recipients including an increased rate of postoperative bacterial infection. It is controversial whether allogeneic transfusion is an independent predictor for the development of postoperative bacterial infection. Methods: We analysed a prospectively collected database of 1,349 patients undergoing colorectal surgery in 11 centres across Canada. The primary outcome was the development of either a postoperative wound infection or intraabdominal sepsis in transfused and nontransfused patients. The effect of allogeneic transfusion on postoperative infection was evaluated with adjustment for all the confounding factors in a multiple regression analysis. Results: The 282 patients who received a total of 832 allogeneic units had a significantly higher frequency of wound infections and intra‐abdominal sepsis than the patients who were not transfused (25.9 vs. 14.2%, p = 0.001). A significant dose‐response relationship between transfusion and infectior, rate was demonstrated. Multiple regression analysis identified allogeneic transfusion as a statistically significant independent predictor for postoperative bacterial infection (OR 1.18, 95% CI 1.05–1.33, p = 0.007). Other independent predictors were anastomotic leak, repeat operation, patient age and preoperative haemoglobin level. The mortality rate was also significantly higher in the transfused group. Conclusion: These data support the hypothesis that allogeneic red cell transfusion is an independent risk factor for the development of postoperative bacterial infection in patients undergoing colorectal surgery. This association provides further reason to minimise exposure to allogeneic transfusions in the perioperative setting.

Allogeneic Red Blood Cell Transfusion Is an Independent Risk Factor for the Development of Postoperative Bacterial Infection

Background and Objectives: Allogeneic red blood cell transfusions may exert immunomodulatory effects in recipients including an increased rate of postoperative bacterial infection. It is controversial whether allogeneic transfusion is an independent predictor for the development of postoperative bacterial infection. Methods: We analysed a prospectively collected database of 1,349 patients undergoing colorectal surgery in 11 centres across Canada. The primary outcome was the development of either a postoperative wound infection or intra–abdominal sepsis in transfused and nontransfused patients. The effect of allogeneic transfusion on postoperative infection was evaluated with adjustment for all the confounding factors in a multiple regression analysis. Results: The 282 patients who received a total of 832 allogeneic units had a significantly higher frequency of wound infections and intra–abdominal sepsis than the patients who were not transfused (25.9 vs. 14.2%, p = 0.001). A significant dose–response relationship between transfusion and infection rate was demonstrated. Multiple regression analysis identified allogeneic transfusion as a statistically significant independent predictor for postoperative bacterial infection (OR 1.18, 95% CI 1.05–1.33, p = 0.007). Other independent predictors were anastomotic leak, repeat operation, patient age and preoperative haemoglobin level. The mortality rate was also significantly higher in the transfused group. Conclusion: These data support the hypothesis that allogeneic red cell transfusion is an independent risk factor for the development of postoperative bacterial infection in patients undergoing colorectal surgery. This association provides further reason to minimise exposure to allogeneic transfusions in the perioperative setting.

Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion.

Most clinical practice guidelines recommend restrictive red cell transfusion practices with the goal of minimising exposure to allogeneic blood (from an unrelated donor). The purpose of this review is to compare clinical outcomes in patients randomised to restrictive versus liberal transfusion thresholds (triggers). To examine the evidence on the effect of transfusion thresholds, on the use of allogeneic and/or autologous blood, and the evidence for any effect on clinical outcomes. Trials were identified by: computer searches of OVID Medline (1966 to December 2000), Current Contents (1993 to Week 48 2000), and the Cochrane Controlled Trials Register (2000 Issue 4). References in identified trials and review articles were checked and authors contacted to identify any additional studies. Controlled trials in which patients were randomised to an intervention group or to a control group. Trials were included where the intervention groups were assigned on the basis of a clear transfusion "trigger", described as a haemoglobin (Hb) or haematocrit (Hct) level below which a RBC transfusion was to be administered. Trial quality was assessed using criteria proposed by Schulz et al. (1995). Relative risks of requiring allogeneic blood transfusion, transfused blood volumes and other clinical outcomes were pooled across trials using a random effects model. Ten trials were identified that reported outcomes for a total of 1780 patients. Restrictive transfusion strategies reduced the risk of receiving a red blood cell (RBC) transfusion by a relative 42% (RR=0.58: 95%CI=0.47,0.71). This equates to an average absolute risk reduction (ARR) of 40% (95%CI=24% to 56%). The volume of RBCs transfused was reduced on average by 0.93 units (95%CI=0.36,1.5 units). However, heterogeneity between these trials was statistically significant (p<0.00001) for these outcomes. Mortality, rates of cardiac events, morbidity, and length of hospital stay were unaffected. Trials were of poor methodological quality. The limited published evidence supports the use of restrictive transfusion triggers in patients who are free of serious cardiac disease. However, most of the data on clinical outcomes were generated by a single trial. The effects of conservative transfusion triggers on functional status, morbidity and mortality, particularly in patients with cardiac disease, need to be tested in further large clinical trials. In countries with inadequate screening of donor blood the data may constitute a stronger basis for avoiding transfusion with allogeneic red cells.

A Meta-Analysis of the Effectiveness of Cell Salvage to Minimize Perioperative Allogeneic Blood Transfusion in Cardiac and Orthopedic Surgery

Concern about risks of allogeneic transfusion has led to an interest in methods for decreasing perioperative transfusion. To determine whether cell salvage reduces patient exposure to allogeneic blood, we performed meta-analyses of randomized trials, evaluating the effectiveness and safety of cell salvage in cardiac or orthopedic elective surgery. The primary outcome was the proportion of patients who received at least one perioperative allogeneic red cell transfusion. Twenty-seven studies were included in the meta-analyses. Cell salvage devices that do not wash salvaged blood were marginally effective in cardiac surgery patients when used postoperatively (relative risk [RR] = 0.85, 95% confidence interval [CI] = 0.79–0.92). Devices that wash or do not wash salvaged blood considerably decreased the proportion of orthopedic surgery patients who received allogeneic transfusion (RR = 0.39, 95% CI = 0.30–0.51 and RR = 0.35, 95% CI 0.26–0.46, respectively). No studies of cell savers that wash salvaged blood during cardiac surgery were included. Cell salvage did not appear to increase the frequency of adverse events. We conclude that cell salvage in orthopedic surgery decreases the risk of patients’ exposure to allogeneic blood transfusion perioperatively. Postoperative cell salvage in cardiac surgery, with devices that do not wash the salvaged blood, is only marginally effective. Implications This meta-analysis of all published randomized trials provides the best current estimate of the effectiveness of cell salvage and is useful in guiding clinical practice. We conclude that cell salvage in orthopedic surgery decreases the proportion of patients requiring allogeneic blood transfusion perioperatively, but postoperative cell salvage is only marginally effective in cardiac surgery.

A meta-analysis of the effectiveness of cell salvage to minimize perioperative allogeneic blood transfusion in cardiac and orthopedic surgery. International Study of Perioperative Transfusion (ISPOT) Investigators.

Concern about risks of allogeneic transfusion has led to an interest in methods for decreasing perioperative transfusion. To determine whether cell salvage reduces patient exposure to allogeneic blood, we performed meta-analyses of randomized trials, evaluating the effectiveness and safety of cell salvage in cardiac or orthopedic elective surgery. The primary outcome was the proportion of patients who received at least one perioperative allogeneic red cell transfusion. Twenty-seven studies were included in the meta-analyses. Cell salvage devices that do not wash salvaged blood were marginally effective in cardiac surgery patients when used postoperatively (relative risk [RR] = 0.85, 95% confidence interval [CI] = 0.79-0.92). Devices that wash or do not wash salvaged blood considerably decreased the proportion of orthopedic surgery patients who received allogeneic transfusion (RR = 0.39, 95% CI = 0.30-0.51 and RR = 0.35, 95% CI 0.26-0.46, respectively). No studies of cell savers that wash salvaged blood during cardiac surgery were included. Cell salvage did not appear to increase the frequency of adverse events. We conclude that cell salvage in orthopedic surgery decreases the risk of patients' exposure to allogeneic blood transfusion perioperatively. Postoperative cell salvage in cardiac surgery, with devices that do not wash the salvaged blood, is only marginally effective. This meta-analysis of all published randomized trials provides the best current estimate of the effectiveness of cell salvage and is useful in guiding clinical practice. We conclude that cell salvage in orthopedic surgery decreases the proportion of patients requiring allogeneic blood transfusion perioperatively, but postoperative cell salvage is only marginally effective in cardiac surgery.

Predonated autologous blood transfusions after total knee arthroplasty: Immediate versus delayed administration

Efforts to avoid complications associated with transfusion of allogeneic blood have increased the use of preoperatively donated autologous blood (PAB). A major controversy has arisen: Should the same criteria be used for transfusion of autologous as allogeneic red cells? This study prospectively and randomly compared giving PAB immediately after total knee arthroplasty (TKA), beginning in the recovery room or delaying a transfusion until the patient's hemoglobin had fallen to less than a 9.0 g/dL transfusion trigger point. The results show that patients who received immediate transfusion had fewer nonsurgical complications ( P < .002). Because TKAs are associated with an average blood loss of 1,400 mL, we recommend that PAB be used in the immediate postoperative period, especially in the elderly, in whom the risk for cardiac or nonsurgical complications is inherently increased.

Where does preoperative erythropoietin therapy count? A mathematical perspective.

The administration of erythropoietin (EPO) can be used to increase a patient's hematocrit (Hct) in the preoperative period and thus possibly preclude the need for allogeneic red cells. However, the exact effect on the postoperative Hct of a given rise in Hct in the preoperative period (and on the avoidance of allogeneic blood) has not been thoroughly evaluated. Equations were developed on the basis of previously described relationships that allowed the assessment of the impact of a given preoperative Hct increase on the postoperative Hct under a variety of clinical situations. Equations were derived that related the change in preoperative Hct after the administration of EPO to the final Hct after a given blood loss. In a typical example (blood volume = 5000 mL, pre-EPO Hct of 40%, post-EPO Hct of 45% after blood losses of 1000, 2000, 3000, 4000, 5000, and 6000 mL), an additional 205, 168, 137, 112, 92, and 75 mL of red cells, respectively, would be present postoperatively over the volume in the same patient who did not receive EPO. For a smaller patient, such as a child (blood volume, 2500 mL), an additional 17 mL (5000-mL blood loss) to 83 mL (1000-mL blood loss) of red cells would be present postoperatively. Hemodilution and EPO act synergistically to yield additional postoperative red cell volume. The use of preoperative EPO with a preoperative increase in Hct results in an increased postoperative Hct after a surgical blood loss. Such a postoperative increase is a function of the volume of blood lost and the patient's blood volume but is independent of the patient's initial Hct. The final postoperative red cell volume increase associated with a preoperative increase in Hct of 1 to 5 percent is limited, however (generally equivalent to a fraction of 1 unit of allogeneic blood). Much of the increase in the patient's Hct vanishes at higher blood losses, and this therapy is most effective with blood loss of <4000 mL. EPO therapy alone may be most effectively used in patients with mild anemia who are undergoing routine surgical procedures that commonly require blood transfusion.

Frequency of immediate adverse effects associated with therapeutic apheresis.

Therapeutic apheresis was found to be reasonably safe in prior studies using instruments that are now largely obsolete. The incidence of adverse effects with current instruments and techniques has not been assessed in a large multicenter study. A survey was conducted in 1995 using a uniform questionnaire that asked about 32 specific events but excluded transient paresthesia and mild vasovagal events. Eighteen centers returned 3429 responses concerning 125 to 500 therapeutic apheresis procedures per center. Two hundred forty-two adverse events were reported in 163 procedures (4.75% of all procedures; 6.87% of first-time procedures and 4.28% of repeat procedures). The numbers (incidence) of selected specific events were transfusion reaction, 56 (51 in plasma exchange [PE] with plasma replacement) (1.6%); citrate-related nausea and/or vomiting, 41 (1.2%); systolic blood pressure <80 mmHg, 34 (1.0%); vasovagal nausea and/or vomiting, 17 (0.5%); pallor and/or diaphoresis, 16 (0.5%); pulse >120, 14 (0.4%); respiratory distress, 9 (0.3%); tetany or seizure, 9 (0.2%); and chills or rigors, 6 (0.2%). Rates for other specific events were < or =0.1 percent. Vasovagal phenomena were more frequent in procedures done in neurologic patients than in those done in hematology or oncology patients (p = 0.011) or renal or rheumatic patients (p = 0.038). Procedure-specific rates were red cell exchange, 8 (10.26%) of 78; PE (plasma), 89 (7.81 %) of 1140; PE (no plasma), 42 (3.35%) of 1255; leukapheresis, 4 (5.71%) of 70; plateletpheresis, 0 of 18; and autologous peripheral blood progenitor cell collection, 11 (1.66%) of 664. Three deaths were reported; all were attributed to primary disease. Therapeutic apheresis procedures are relatively safe, with a 4.75-percent overall incidence of mostly reversible adverse effects. Among the most commonly performed procedures, the risk is higher for blood component exchanges, especially if allogeneic red cell or plasma transfusion occurs, and lower for peripheral blood progenitor cell collection.

Platelet-rich plasmapheresis in cardiac surgery: A meta-analysis of the effect on transfusion requirements

Objective:Our purpose was to determine whether intraoperative platelet-rich plasmapheresis in cardiac surgery is effective in reducing the proportion of patients exposed to allogeneic red cell transfusions. Methods: A systematic search for prospective, randomized trials of platelet-rich plasmapheresis in cardiac surgery, using MEDLINE, HEALTHSTAR, Current Contents, “Biological Abstracts,” and EMBASE/Excerpta Medica up to August 1997, was completed. Trials were included if they reported either the proportion of patients exposed to allogeneic red cells or the units of allogeneic red cells transfused. Trials were abstracted by 2 independent investigators and the quality of trial design was assessed with the use of a validated scale. Results: Seventeen references met the inclusion criteria (1369 patients [675 control: 694 platelet-rich plasmapheresis]). Platelet-rich plasmapheresis reduced the likelihood of exposure to allogeneic red cells in cardiac surgery (odds ratio 0.44; 95% confidence interval 0.27, 0.72, P = .001). Platelet-rich plasmapheresis had a small but statistically significant effect on both the volume of blood lost in the first 24 hours (weighted mean difference –102 mL; 95% confidence interval –148, –55 mL, P < .0001) and the mean units transfused (weighted mean difference –0.33 units; 95% confidence interval –0.43, –0.23, P < .0001). However, platelet-rich plasmapheresis was only marginally effective (odds ratio 0.83, 95% confidence interval 0.34, 2.01, P = .68) for “good” quality trials, whereas it appeared very effective in trials with poor methodologic quality (odds ratio 0.33, 95% confidence interval 0.17, 0.62, P = .0007). Conclusions: Although platelet-rich plasmapheresis appeared effective in decreasing the proportion of patients receiving transfusions after cardiac operations, the quality of most of the supporting trials was low and the benefit was small in trials of good quality. Further clinical trials should be completed. (J Thorac Cardiovasc Surg 1998;116:641-7)

Erythropoietin to minimize perioperative blood transfusion: a systematic review of randomized trials. The International Study of Peri-operative Transfusion (ISPOT) Investigators.

Our aim was to perform a systematic review to determine the efficacy and side-effects of erythropoietin, given with or without autologous predonation, to patients undergoing orthopaedic or cardiac surgery. A number of studies have been done to determine whether erythropoietin minimizes exposure to perioperative allogeneic red cell transfusion. A systematic review of all randomized trials will provide the best estimate of the efficacy and side-effects of erythropoietin therapy. All randomized trials of erythropoietin in cardiac or orthopaedic surgery that reported the proportion of patients receiving perioperative allogeneic transfusion were included. The efficacy of erythropoietin was evaluated in subgroups of patients depending upon the route of administration, dose of erythropoietin, the type of control and the methodological quality of the study report. The odds ratio for the proportion of patients transfused with allogeneic blood in studies of erythropoietin to augment autologous donation was 0.42 (95% confidence limits 0.28-0.62; P < 0.0001) for orthopaedic surgery and 0.25 (95% CI 0.08-0.82; P = 0.02) for cardiac surgery. The odds ratio for erythropoietin alone was 0.36 (95% CI 0.24-0.56; P = 0.0001) in orthopaedic surgery and 0.25 (95% CI 0.06-1.04; P < 0.06) in cardiac surgery. The route of administration, dose of erythropoietin, type of control and methodological quality of the study report had no statistically significant effect upon the odds ratios. Although there was no convincing evidence that erythropoietin used alone increased the frequency of thrombotic complications, some studies found an excess of events in erythropoietin-treated patients, and the number of patients studied was relatively small. Erythropoietin, when given alone or to augment autologous donation, decreased exposure to perioperative allogeneic transfusion in orthopaedic and cardiac surgery. Further studies are required to definitively establish the safety of erythropoietin alone, to determine the optimal dose of perioperative erythropoietin, and to compare its efficacy and cost-effectiveness with other methods of minimizing perioperative transfusion.

Transfusion Practices in Primary Total Joint Replacements in Finland

Abstract Background and Objectives: A multicenter survey was carried out in 11 Finnish hospitals to determine the prevailing transfusion practices in orthopedic surgery. Materials and Methods: The records of 1,161 patients who had undergone primary total hip (THR) or knee replacement (TKR) were reviewed. Results: Allogeneic red cells (RBC) were administered to 92% of the THR patients and to 84% of the patients undergoing TKR. Significant interhospital variation in RBC transfusion, from 2.4 to 4.1 units per patient in THR and from 1.8 to 2.8 units in TKR, was detected after adjustment for clinical and laboratory findings. Conclusion: The use of RBCs in orthopedic surgery was generous compared with reports from other European countries and the US. Each hospital's individual transfusion policy seemed to be a strong determinant of allogeneic blood use.

The first randomized trial of human polymerized hemoglobin as a blood substitute in acute trauma and emergent surgery

Background: Human polymerized hemoglobin (PolyHeme) is a universally compatible, disease-free, oxygen-carrying resuscitative fluid. This is the first prospective, randomized trial to compare directly the therapeutic benefit of PolyHeme with that of allogeneic red blood cells (RBCs) in the treatment of acute blood loss. Study Design: Forty-four trauma patients (33 male, 11 female) aged 19–75 years with an average Injury Severity Score (ISS) score of 21 ± 10 were randomized to receive red cells (n = 23) or up to 6 U (300 g) of PolyHeme (n = 21) as their initial blood replacement after trauma and during emergent operations. Results: There were no serious or unexpected adverse events related to PolyHeme. The PolyHeme infusion of 4.4 ± 2.0 units (mean ± SD) resulted in a plasma [Hb] of 3.9 ± 1.3 g/dL, which accounted for 40% of the total circulating [Hb]. There was no difference in total [Hb] between the groups before infusion (10.4 ± 2.3 g/dL control vs. 9.4 ± 1.9 g/dL experimental). At end-infusion the experimental RBC [Hb] fell to 5.8 ± 2.8 g/dL vs. 10.6 ± 1.8 g/dL (p < 0.05) in the control, although the total [Hb] was not different between the groups or from pre-infusion. The total number of allogeneic red cell transfusions for the control and experimental groups was 10.4 ± 4.2 units vs. 6.8 ± 3.9 units (p < 0.05) through day 1, and 11.3 ± 4.1 units vs. 7.8 ± 4.2 units (p = 0.06) through day 3. Conclusions: PolyHeme is safe in acute blood loss, maintains total [Hb] in lieu of red cells despite the marked fall in RBC [Hb], and reduces the use of allogeneic blood. PolyHeme appears to be a clinically useful blood substitute.

Transfusion Practices in Primary Total Joint Replacements in Finland

Background and Objectives: A multicenter survey was carried out in 11 Finnish hospitals to determine the prevailing transfusion practices in orthopedic surgery. Materials and Methods: The records of 1,161 patients who had undergone primary total hip (THR) or knee replacement (TKR) were reviewed. Results: Allogeneic red cells (RBC) were administered to 92% of the THR patients and to 84% of the patients undergoing TKR. Significant interhospital variation in RBC transfusion, from 2.4 to 4.1 units per patient in THR and from 1.8 to 2.8 units in TKR, was detected after adjustment for clinical and laboratory findings. Conclusion: The use of RBCs in orthopedic surgery was generous compared with reports from other European countries and the US. Each hospital’s individual transfusion policy seemed to be a strong determinant of allogeneic blood use.

Intraoperative autotransfusion is associated with modest reduction of allogeneic transfusion in prosthetic hip surgery.

The efficacy of intraoperative salvage and washing of wound blood and the predictors of allogeneic red cell transfusions in prosthetic hip surgery are insufficiently known. In 96 patients, undergoing primary or revision surgery, salvaged and washed red cells and, if necessary, allogeneic blood were used to keep haematocrit not lower than 33%. The bleeding of red cells during hospital stay was calculated from the red cell balance. The preoperative red cell reserve (mililitres of red cells in excess of a haematocrit of 33%) was estimated and the difference between this volume and the total bleeding of red cells was retrospectively used to classify patients with regard to the need for red cells. Stepwise regression analysis was used to define patient-related variables associated with allogeneic blood transfusion. Preoperative knowledge of the type of operation (primary, revision), the preoperative red cell reserve, and the body mass could predict roughly half of the need for banked blood (r2 = 0.45). Only one-third of the total bleeding of red cells was retransfused. For complete avoidance of allogeneic blood, autotransfusion was most effective in patients with a moderate need (0-4 u). However, 32% of such patients required allogeneic blood. Autotransfusion has a limited efficacy to decrease the need for allogeneic blood, and other blood-saving methods should be added for this purpose. It is difficult to predict the need for allogeneic blood preoperatively.