Red cell requirements for intensive care units adhering to evidence-based transfusion guidelines

BACKGROUND: Anemia commonly complicates critical illness. Restrictive transfusion triggers are appropriate in this setting, but no large studies have measured red cell (RBC) requirements for intensive care patients when evidence-based transfusion guidelines are followed consistently. STUDY DESIGN AND METHODS: Data were recorded daily for 1023 of 1042 sequential admissions to 10 intensive care units (ICUs) over 100 days. The sample comprised 44 percent of all ICU admissions in Scotland during this period. RBC transfusions and the occurrence of clinically significant hemorrhage were recorded for every ICU day. Transfusion episodes were classified as either associated with or not associated with hemorrhage. Measures of RBC use were derived for the cohort and for Scotland with national audit data. RESULTS: A total of 39.5 percent (95% confidence interval [CI], 36.5%-42.5%) of admissions received transfusions. Eighteen percent of admissions received at least one transfusion associated with hemorrhage and 26 percent received at least one transfusion not associated with hemorrhage. The median (interquartile range) transfusion trigger in the absence of hemorrhage was 78 (73-78) g/L. The overall mean RBC use was 1.87 (95% CI, 1.79-1.96) units per admission or 0.34 (95% CI, 0.33-0.36) units per ICU-day. Forty-seven percent of RBCs administered were not associated with clinically significant hemorrhage. Mean RBC requirements for intensive care in Scotland were estimated to be 3950 (95% CI, 3780-4140) per million-adult-population per year. This represented 7 to 8 percent of the Scottish blood supply. CONCLUSIONS: Despite evidence-based transfusion practice, 40 percent of ICU patients receive transfusions, which account for 7 to 8 percent of the national blood supply.     

Red blood cell use outside the operating theater: a prospective observational study with modeling of potential blood conservation during severe blood shortages

BACKGROUND: National guidance recommends planning for future blood shortages, but few studies have evaluated how reduced demand could be achieved acutely.
STUDY DESIGN AND METHODS: A trained observer collected data concerning red blood cell (RBC) transfusion events outside the operating theater during 68 hours of blood bank monitoring over 7 weeks. Data were gathered at the patients' bedside from clinical staff and charts. Transfusions were classified according to the presence of bleeding and medical specialty (medical, surgical, other). Hemoglobin (Hb) transfusion triggers, RBCs transfused, and posttransfusion Hb values were collected. Evidence-based scenarios were used to model the potential RBC savings that could be achieved if acute shortages occurred, incorporating ischemic heart disease as a potential decision modifier.
RESULTS: A total of 83 patients received 100 transfusion events, comprising 207 RBC units, during the sampling periods. The relative use of RBC units across specialties was as follows: medical, 74%; surgical, 22%; and other, 4%. For medical and surgical patients, respectively, 31 and 10% of all RBC units were transfused for anemia without evidence of bleeding, and 38 and 12% were transfused for non–life-threatening bleeding. Eight-five percent of all patients who received transfusions had stable vital signs before transfusion. Our model suggested that only 11% of RBCs would be conserved by cancellation of major surgery, whereas 23% to 47% of all RBCs could be conserved by controlling transfusions to medical patients.
CONCLUSION: In institutions with patterns of blood use similar to ours, control of transfusions to medical patients is the most effective response to acute blood shortages.     

Incidence of red cell antibodies after multiple blood transfusion

A retrospective study was performed to estimate the frequency of alloimmunization against red cell (RBC) antigens in a multiply transfused group. Patients (n = 186) were studied who had received at least six blood transfusions during a period of at least 3 months. Some 6944 units of blood were transfused. One hundred forty patients had hematologic disorders. The patients' sera were investigated every 3 months with indirect antiglobulin tests and enzyme-treated RBCs. Twenty-two patients (11.8%) made 33 antibodies. Seven patients made more than one antibody. Eight of the 22 patients (36.4%) made their first antibody before or at the 10th transfusion. The risk of immunization increased with the number of transfusions. Influence of gender and age was not demonstrable. Nor was a relationship demonstrated between blood transfusion reactions and RBC antibody formation; no delayed hemolytic transfusion reactions occurred. Anti-E was demonstrated in 12 patients and anti-K in 15. When the gene frequencies were taken into account, it appeared that anti-E was made by 11.5 percent of E-negative patients, most of whom were immunized after an estimated three transfusions with E-positive blood. Anti-K was made by 8.7 percent of the K-negative patients, after an estimated 2.1 units of K-positive blood. It might be desirable to match red cell units for the E and K antigens in patients at relatively high risk. These are primarily patients who have already formed an antibody and are going to receive many transfusions and women of childbearing age who are to receive more than 4 units of blood.     

Emergency department blood transfusion predicts early massive transfusion and early blood component requirement

BACKGROUND: The purpose of this study was to evaluate the ability of uncrossmatched transfusions in the emergency department (ED) to predict early (<6 hr) massive transfusion (MT) of red blood cells (RBCs) and blood components. STUDY DESIGN AND METHODS: All patients admitted to a Level 1 trauma center between July 2005 and June 2007 who received any transfusions and were transported directly from the scene of injury were included. Early MT was defined as the need for 10 U or more or RBCs in the first 6 hours. Early MT plasma was defined as 6 U or more of plasma in the first 6 hours. Early MT platelets (PLTs) were defined as two or more apheresis transfusions in the first 6 hours. Univariate and multivariate analyses were performed. RESULTS: A total of 485 patients (34%) received ED transfusions (ED RBC+) and 956 (66%) did not receive ED transfusions (ED RBC–). ED RBC+ patients were younger, were more likely to be male, and arrived with more severe injuries. Multivariate regression identified ED transfusion of uncrossmatched RBC as an independent predictor of requiring early MT of RBCs (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.36‐7.59; p = 0.001), plasma (OR, 2.7; 95% CI, 1.66‐4.39; p < 0.001), and PLTs (OR, 1.9; 95% CI, 1.08‐3.41; p = 0.025). CONCLUSION: Patients receiving uncrossmatched RBCs in the ED are more than three times more likely to receive early MT of RBCs. Additionally, patients transfused with ED RBCs are more likely to receive 6 units or more of plasma and two or more apheresis PLT transfusions. Given these findings, ED transfusion of uncrossmatched RBCs should be considered a potential trigger for activation of an institution's MT protocol.     

A pilot feasibility trial of allocation of freshest available red blood cells versus standard care in critically ill patients

BACKGROUND: Prolonged storage of red blood cells (RBCs) may increase posttransfusion adverse events in critically ill patients. We aimed to evaluate in intensive care unit (ICU) patients 1) the feasibility of allocating freshest available compatible RBCs versus standard care and 2) the suitability of this approach in the design of a large randomized controlled trial (RCT). STUDY DESIGN AND METHODS: Eligible patients from two adult ICUs were randomly assigned to receive either the freshest available compatible RBCs or the standard care (the oldest compatible available RBCs) for all transfusions during their ICU stay. Study group allocation was concealed from patients and bedside clinicians, but the transfusion service was unblinded. The study endpoints were the feasibility of the study procedures, including success of the ICU Web randomization, the ICU staff blinding, and the correct delivery of the RBC units by the transfusion service in accordance with the allocated study group. In addition, we measured the difference in age of RBC units between the two groups. RESULTS: During a 3‐month period, 177 RBC units were delivered to 51 patients. All study procedures, including randomization, blinding, and delivery of blood in accordance with the study group were successful. The mean (±SD) of the mean age of the RBC received by each patient was lower in the “fresher blood” group compared with the standard care group (12.1 [±3.8] days vs. 23 [±8.4] days; p < 0.001). CONCLUSION: Randomized delivery of the freshest available RBCs versus standard care to ICU patients who were prescribed transfusion for clinical reasons is feasible, with a clinically relevant degree of storage duration separation achievable between the two study groups. These findings support the feasibility of a future large pragmatic RCT.     

Therapeutic efficacy and safety of red blood cells treated with a chemical process (S-303) for pathogen inactivation: a Phase III clinical trial in cardiac surgery patients

BACKGROUND: A randomized, double-blind trial is reported of the clinical efficacy of red blood cells (RBCs) treated for pathogen inactivation with S-303, a synthetic labile alkylating agent. STUDY DESIGN AND METHODS: Patients undergoing complex cardiac surgeries were randomly assigned to receive either S-303-treated (test) or conventional (control) RBC transfusion during surgery and for 6 days thereafter. Efficacy was evaluated by comparing the occurrence of a composite primary endpoint of treatment-related morbidity (myocardial infarction and renal failure) and mortality. RESULTS: Two-hundred twenty-three patients were randomly assigned and 148 patients who received transfusions (74 with S-303-treated RBCs and 74 with control RBCs) were evaluable. The incidence of the primary endpoint was equivalent between the two groups (22 and 21% in the S-303-treated and control RBC groups, respectively). Secondary endpoints, including hemoglobin increment (mean, 1.4 vs. 1.5 g/dL), number of RBC transfusions (mean, 4.4 vs. 3.8 units), and other blood product support, were also comparable. The adverse event profile was similar between groups; however, patients who received S-303 RBCs were significantly more likely to develop constipation and less likely to suffer supraventricular extrasystoles. Four patients (2 test and 2 control) demonstrated positive indirect antiglobulin tests with reactivity for S-303 RBCs at one or more time points before or after transfusion, without evidence of hemolysis. CONCLUSION: S-303-treated and conventional RBCs were equivalent with respect to clinical efficacy and safety in supporting the transfusion needs of cardiac surgery patients. Investigations are under way to ascertain the significance of S-303 RBC antibodies and to prevent their occurrence.     

Removal of white cells from red cells by transfusion through a new filter

The effectiveness of a new filter (RC100) for the preparation of white cell-depleted red cells (RBCs) at the bedside was evaluated in vitro and in vivo using three RBC products: standard RBC concentrate (CPDA units), RBCs suspended in saline-adenine-glucose-mannitol additive solution after the removal of plasma (SAGM units), and RBCs suspended in SAGM after the removal of plasma and buffy coat (SAGM-BC units). Median RBC recovery was at least 92 percent when 2 units were administered through one filter; median values for residual white cells and platelets were less than or equal to 20 × 10(6) and less than or equal to 2.5 × 10(9) per 2 units, respectively. The in vivo study was carried out in 80 multiply transfused patients with thalassemia, 35 of whom had experienced frequent nonhemolytic transfusion reactions when given standard or buffy coat-free RBCs. During the 6-month study, each patient was given two transfusions of each type of RBC product One febrile nonhemolytic transfusion reaction occurred in each of two patients receiving SAGM-BC units, but in no other case. If the flow rate is not reduced, the median transfusion time is 35 minutes per CPDA unit and 15 minutes per SAGM and SAGM-BC unit. It is concluded that the transfusion of RBCs through the RC100 is a simple and effective procedure to administer white cell-depleted RBCs prepared at the bedside.     

Efficacy,recovery, and safety of RBCs from autologous placental blood: clinical experience in 52 newborns

BACKGROUND: In the present study, the efficacy, recovery, and safety of RBCs from autologous placental blood (PB-RBCs) were investigated. STUDY DESIGN AND METHODS: A total of 52 newborns received transfusion with PB-RBCs. The number of newborns requiring no additional allogeneic RBCs was calculated. In 22 of these 52 neonates with a birth weight of 1000 to 2500 g, vital measures were performed during transfusion, and serum potassium levels were measured up to 3 days after transfusion. The results were compared with those of a matched control group given allogeneic RBC transfusions. RESULTS: All neonates of the study group with a birth weight of less than 1000 g, but only 59 percent those with a birth weight of 1000 to 2500 g and 58 percent of those requiring surgery directly after delivery needed allogeneic transfusions in addition to PB-RBCs. The mean Hb increase after RBC transfusion of 10 mL per kg of body weight was 3 g per dL per kg of body weight in both groups; the Hb decrease was accelerated in the placental blood group (0.32 vs. 0.24 g/dL/day; p < 0.05). There were no intergroup differences in the vital parameters. CONCLUSION: Our results show no difference in efficacy and safety between PB-RBC transfusion and allogeneic RBC transfusion. According to well-defined criteria, 40 percent of anemic neonates can be supported by autologous placental blood transfusions alone.     

Absence of D- alloimmunization in AIDS patients receiving D-mismatched RBCs

BACKGROUND: More than 80 percent of D- patients who receive D+ blood become alloimmunized to the D antigen. Anemia occurs in most AIDS patients at some point in the disease. D- patients with AIDS may require blood transfusion and, during times of blood shortage, may receive D+ RBCs. They would be expected to become alloimmunized to the d antigen. STUDY DESIGN AND METHODS: The records of the transfusion service between January 1996 and July 2000 were reviewed for D- patients who received D+ blood. IATs were performed before the initial transfusion and subsequently when the patient required further RBC transfusion. RESULTS: Eight D- AIDS patients who received multiple transfusions (three women and five men; age range, 31-44 years; mean, 44 years) who received between 2 and 11 units (mean, 6.25) of D+ RBCs were identified. Antibody screens were performed at 8 to 65 weeks after transfusion. It was found that none of the eight D- AIDS patients developed anti-D. ABO antibodies were found as expected. During the same period, it was found that six D- patients admitted with other diagnoses who received 1 to 9 units of D+ RBCs, all developed anti-D within 7 to 19 weeks of transfusion. CONCLUSION: Patients with AIDS may not form alloantibodies to the D antigen. This may be attributable to their immunodepressed state, particularly to the decrease in CD4+ T lymphocytes. Therefore, during blood shortages, transfusion of D+ blood to D- AIDS patients may be without any subsequent consequence.     

Prospective RBC phenotype matching in a stroke-prevention trial in sickle cell anemia: a multicenter transfusion trial

BACKGROUND: Most sickle cell anemia patients undergo transfusion therapy to prevent complications. The Stroke Prevention Trial in Sickle Cell Anemia showed that transfusion therapy is effective in the primary prevention of stroke. Despite its efficacy, transfusion therapy is limited by alloimmunization. The purpose of this study was to determine if a multicenter trial could implement a transfusion program utilizing phenotypically matched blood to reduce alloimmunization. STUDY DESIGN AND METHODS: One hundred thirty children underwent RBC phenotyping and antibody screening with review of blood bank records. The protocol required use of WBC-reduced RBCs, which were matched for E, C, and Kell. Monthly alloantibody testing and review of transfusion forms were performed to determine compliance and the occurrence of any adverse events. RESULTS: Patient RBCs expressed a low frequency of Kell (2%), E (20%), and C (25%) antigens. Sixty-one patients received 1830 units. Ninety-seven percent of all units were WBC reduced. Only 29 units were inadvertently not matched for E, C, and Kell. Five patients (8%) developed a clinically significant alloantibody. Four developed a single antibody to E or Kell. Three patients (5%) developed a warm autoantibody. There were 11 transfusion reactions and 8 transfusion-associated events. Transfusion reactions included 6 febrile reactions (0.33%/unit), 3 allergic (0.16%/unit), and 2 hemolytic (0.11%/unit). Associated events included 4 episodes of hypertension (0.22%/unit), 3 crises (0.16%/unit), and 1 transient ischemic attack (0.05%/unit). CONCLUSION: This is the first multicenter study to show that extended RBC phenotyping can be implemented nationwide. Compared to studies, the alloimmunization rate dropped from 3 percent to 0.5 percent per unit, and hemolytic transfusion reactions dropped by 90 percent. It is recommended that all transfused sickle cell anemia patients be antigen matched for E, C, and Kell. Patients should be closely monitored during transfusions to avoid preventable risks.     

Why is fresh-frozen plasma transfused?

A three-part study to determine the reasons for fresh-frozen plasma (FFP) transfusions at hospitals in southeastern Wisconsin was conducted. During a 1-month period, hospital transfusion services reported that patients undergoing open-heart surgery received 42 percent, medical patients 26 percent, noncardiac surgery patients 23 percent, neonatal patients 1 percent, and other patients 7 percent of the FFP transfused. In the second phase of the study, the records of 102 patients receiving FFP during a 1-month period at two teaching hospitals were reviewed. Justification for the FFP transfusion was provided in the hospital chart for only 11 percent of the transfusion episodes, although abnormal results of coagulation studies or signs of hypovolemia were recorded for an additional 51 percent. Frequently, FFP and red cell (RBC) transfusions were given during the same transfusion episode. In the third phase of the study, clinicians completed a questionnaire specifying their "trigger" for prescribing FFP: bleeding (43% of episodes), abnormal coagulation studies (26%), signs/symptoms of hypovolemia (16%), and "other" (15%). They judged that the FFP transfusion was effective in 47 percent of transfusion episodes and ineffective in only 6 percent. These findings indicate that FFP is used mainly as a source of coagulation factor replacement in hospitals served by The Blood Center of Southeastern Wisconsin, that justification for FFP use rarely is provided in patient records, that both FFP and RBCs are frequently transfused together, and that clinicians believe FFP is beneficial for their patients. Educational efforts addressing appropriate use of FFP should be initiated.     

Cytomegalovirus infections in seropositive patients after transfusion. The effect of red cell storage and volume

Antibody responses to cytomegalovirus (CMV) after red cell (RBC) transfusion were studied in 84 seropositive surgery patients and 82 seropositive oncology patients. The surgery patients were randomized to receive RBCs stored either 3 to 8 or 20 to 42 days after donation. Of 38 patients receiving RBCs stored 8 days or less, 3 developed a rise in titer (4-fold increase) of IgG antibody to CMV 8 to 12 weeks after transfusion. This rate of response (8%) did not differ significantly (p = 0.23) from that (16%) in the 46 patients receiving RBCs stored 20 to 42 days. Seropositive oncology patients were randomized to receive RBCs from seronegative or random donors. Five (19%) of 27 oncology patients receiving seronegative RBCs and 13 (23%) of 55 patients receiving random RBCs (mean, 2 seropositive RBC units/patient) developed a rise in titer of antibody to CMV. No CMV morbidity occurred in either patient group. For both patient groups, a rise in titer of antibody to CMV was associated with the number of transfused RBC units. These results confirm that CMV-seronegative RBCs are unnecessary for infrequently transfused seropositive patients. They also suggest that multiple transfusions of stored RBCs are as immunosuppressive as multiple transfusions of RBCs used within a few days after donation.     

Posttransfusion recovery of stored red blood cells in very low birth weight infants using a hemoglobin balance model

BACKGROUND: A Hb balance model was used in very low birth weight (VLBW) infants to predict posttransfusion Hb levels from which we inferred allogeneic RBC recovery after transfusion of RBCs stored for varying periods of time. STUDY DESIGN AND METHODS: Premature VLBW infants receiving RBC transfusions during the 1st month of life were evaluated retrospectively for RBC survival of stored donor blood. Actual Hb levels measured in infant blood 1 and 2 days after RBC transfusions were compared to those predicted using a Hb balance model based on factors affecting blood Hb loss and gain. Transfusions were subgrouped according to whether or not infants were clinically stable at the time of RBC transfusion. Model-predicted RBC recovery was also evaluated relative to duration of RBC storage. RESULTS: Model-predicted mean (+/- SD) Hb levels 2 days after transfusion among the 30 VLBW infants receiving a total of 57 RBC transfusions were only 4 percent higher than actual values observed (15.2 +/- 1.2 g/dL vs. 14.7 +/- 1.4, respectively; p < 0.05). The infant's clinical status at the time of transfusion did not affect predicted 1- and 2-day posttransfusion RBC recovery. Model-predicted recovery of transfused RBCs was modestly, but significantly, decreased with increasing duration of donor RBC storage (i.e., 10% lower by 42 days-the maximal allowed storage period for donor blood [p < 0.01]). CONCLUSIONS: Our model-predicted RBC survival results are consistent with-but not direct evidence of-hemolysis of donor blood after RBC transfusion. Although observed post-RBC Hb levels 2 days after transfusion averaged only 4 percent less than predicted, model-predicted survival of donor RBCs at 42 days suggested a modest decrease (i.e., by 10%).     

Transfusion management of sickle cell patients during bone marrow transplantation with matched sibling donor

BACKGROUND: Sickle cell disease (SCD) patients have unique transfusion considerations during bone marrow transplantation (BMT), including prophylaxis against stroke and alloimmunization. Characterization of transfusion requirements is important for blood bank and clinician patient management.
STUDY DESIGN AND METHODS: A retrospective analysis of red blood cell (RBC) and platelet (PLT) transfusion of SCD patients during myeloablative matched sibling donor (MSD) BMT at one institution from 1993 to 2007 was performed. Patient characteristics (RBC blood group antibodies, ABO-incompatible donor, BMT-related morbidity) and transfusion practices (RBC phenotype matching, transfusion threshold, and blood age) were assessed for effect on total RBC transfusion volumes.
RESULTS: Twenty-seven patients received MSD BMT with 96% survival and 0% rejection. Six alloimmunized patients received RBCs with extended phenotype matching (C, c, E, e, K, Fy^a, Jk^b), 14 nonalloimmunized received limited matching (C, c, E, e, K), and 7 did not have phenotype matching. Among 26 survivors, a median seven RBC transfusions (range, 3-15) and 13.5 PLT transfusions (range, 4-48) per patient were administered, equivalent to 64 mL/kg RBCs (range, 22-122 mL/kg) and 106 mL/kg PLTs (range, 26-343 mL/kg). BMT-related morbidity predicted increased RBC transfusions (p = 0.006). Venoocclusive disease was associated with greater RBC (p = 0.016) and PLT transfusion volumes (p = 0.016). Greater phenotype matching was associated with decreased RBC transfusions (p = 0.0247).
CONCLUSIONS: SCD patients have high transfusion support during MSD BMT. Communication of BMT complications to the blood bank is essential for transfusion inventory management. Phenotype matching decreased RBC transfusions in this cohort and warrants further investigation in SCD transfusion therapy.     

The CRIT Study: Anemia and blood transfusion in the critically ill--current clinical practice in the United States

OBJECTIVE: To quantify the incidence of anemia and red blood cell (RBC) transfusion practice in critically ill patients and to examine the relationship of anemia and RBC transfusion to clinical outcomes. DESIGN: Prospective, multiple center, observational cohort study of intensive care unit (ICU) patients in the United States. Enrollment period was from August 2000 to April 2001. Patients were enrolled within 48 hrs of ICU admission. Patient follow-up was for 30 days, hospital discharge, or death, whichever occurred first. SETTING: A total of 284 ICUs (medical, surgical, or medical-surgical) in 213 hospitals participated in the study. PATIENTS: A total of 4,892 patients were enrolled in the study. MEASUREMENTS AND MAIN RESULTS: The mean hemoglobin level at baseline was 11.0 +/- 2.4 g/dL. Hemoglobin level decreased throughout the duration of the study. Overall, 44% of patients received one or more RBC units while in the ICU (mean, 4.6 +/- 4.9 units). The mean pretransfusion hemoglobin was 8.6 +/- 1.7 g/dL. The mean time to first ICU transfusion was 2.3 +/- 3.7 days. More RBC transfusions were given in study week 1; however, in subsequent weeks, subjects received one to two RBC units per week while in the ICU. The number of RBC transfusions a patient received during the study was independently associated with longer ICU and hospital lengths of stay and an increase in mortality. Patients who received transfusions also had more total complications and were more likely to experience a complication. Baseline hemoglobin was related to the number of RBC transfusions, but it was not an independent predictor of length of stay or mortality. However, a nadir hemoglobin level of <9 g/dL was a predictor of increased mortality and length of stay. CONCLUSIONS: Anemia is common in the critically ill and results in a large number of RBC transfusions. Transfusion practice has changed little during the past decade. The number of RBC units transfused is an independent predictor of worse clinical outcome.     

Timing of RhD-positive red blood cell administration is associated with D-alloimmunization in injured patients

Background

The D-alloimmunization rate in trauma patients does not appear to depend on the number of RhD-positive units transfused. The effect of the timing and pattern of RhD-positive transfusions has not been evaluated.

Methods

RhD-negative trauma patients who were transfused with RhD-positive red blood cells (RBC) or low titer group O whole blood (collectively called RBCs) on at least two separate calendar days and who had antibody detection tests performed at least 14 days after the second RhD-positive RBC transfusion without receiving RhIg were included in the analysis. Patients whose anti-D was detected within 14 days of the index RhD-positive RBC transfusion were excluded. Patient demographics and the dates of RhD-positive RBC transfusions and results of antibody detection tests performed after the index transfusion were collected on eligible patients.

Results

There were 44/61 (72.1%) patients in whom anti-D was not detected (non-alloimmunized) and 17/61 (27.9%) in whom anti-D was detected (alloimmunized). The patients had similar demographics with trends towards higher median admission heart rates and lower median admission Glasgow Coma Scale values in the alloimmunized group. Both groups received statistically identical median quantities of RhD-positive RBCs (non-alloimmunized 5 vs. alloimmunized 4 units, p = .53), however, the alloimmunized group received all their RhD-positive RBCs over a significantly shorter period of time compared to the non-alloimmunized (median 4 vs. 15 days, respectively, p = .01).

Conclusion

Receipt of all RhD-positive RBCs over a shorter period of time was associated with higher D-alloimmunization rates. These results need to be confirmed in larger studies.     

Anemia and blood transfusion in the critically ill patient: role of erythropoietin

Critically ill patients receive an extraordinarily large number of blood transfusions. Between 40% and 50% of all patients admitted to intensive care units receive at least 1 red blood cell (RBC) unit during their stay, and the average is close to 5 RBC units. RBC transfusion is not risk free. There is little evidence that 'routine' transfusion of stored allogeneic RBCs is beneficial to critically ill patients. The efficacy of perioperative recombinant human erythropoietin (rHuEPO) has been demonstrated in a variety of elective surgical settings. Similarly, in critically ill patients with multiple organ failure, rHuEPO therapy will also stimulate erythropoiesis. In a randomized, placebo-controlled trial, therapy with rHuEPO resulted in a significant reduction in RBC transfusions. Despite receiving fewer RBC transfusions, patients in the rHuEPO group had a significantly greater increase in hematocrit. Strategies to increase the production of RBCs are complementary to other approaches to reduce blood loss in the intensive care unit, and they decrease the transfusion threshold in the management of all critically ill patients.     

A multicenter pilot-randomized controlled trial of the feasibility of an augmented red blood cell transfusion strategy for patients treated with induction chemotherapy for acute leukemia or stem cell transplantation

BACKGROUND: Anemia may be an important factor contributing to an increased risk of bleeding, particularly in patients with thrombocytopenia. STUDY DESIGN AND METHODS: A multicenter, single-blinded pilot randomized controlled trial (RCT) was performed to evaluate the feasibility of conducting a larger RCT to determine the effect of the hemoglobin (Hb) concentration on bleeding risk. Patients with acute leukemia receiving induction chemotherapy or those undergoing stem cell transplantation were assigned to one of two treatment groups: standard transfusion strategy (transfusion of 2 units of red blood cells [RBCs] when their Hb level was less than 80 g/L) or an augmented transfusion strategy (transfusion of 2 units of RBCs when their Hb level was less than 120 g/L). RESULTS: Sixty patients were enrolled: 29 in the control group and 31 in the experimental group. The proportions of patients experiencing clinically significant bleeding and the time to first bleed were not significantly different between the control and experimental groups. The experimental group received more RBC transfusions (transfusions/patient-day) than the control group (0.233 vs. 0.151; relative risk, 1.56; 95% confidence interval, 1.16-2.10; p = 0.003). The proportion of patient-days with platelet (PLT) transfusions was not different between the experimental and control groups. The mean number of donor exposures (PLT and RBC transfusions) was not different between experimental and control groups. Bleeding symptoms were systematically documented. CONCLUSION: This pilot study thus indicated that it would be feasible to enroll the required number of patients to enable the performance of a large RCT to investigate the effect of Hb on bleeding risk in thrombocytopenic patients.     

Changing patterns of blood transfusions in four sets of United States hospitals, 1980 to 1985

Annual transfusion activity between 1980 and 1985 was surveyed in four sets of United States (US) hospitals, which together accounted for 4.8 percent of the red cell (RBC) transfusions in the US in 1980. Total RBC transfusion rates (total RBCs transfused/1000 hospital admissions) increased between 1980 and 1982 but remained nearly constant between 1982 and 1985. Plasma transfusion dynamics followed a similar pattern, whereas the preoperative deposit of autologous blood by patients accelerated rapidly after 1982. These changes appear to reflect responses to the acquired immune deficiency syndrome epidemic. In contrast, total platelet transfusion rates grew by 76 percent during the 6-year period, approaching total RBC rates by 1985. This is the first reported evidence in such a large sample of transfusions that total RBC transfusion rates have moderated.     

Blood management in intensive care medicine: CRIT and ABC--what can we learn?

In 284 US intensive care units the CRIT study (Anemia and blood transfusion in the critically ill--Current clinical practice in the United States) assessed allogeneic red blood cell (RBC) transfusion and outcome in 4892 patients. As in the former European ABC study (Anemia and blood transfusion in the critically ill), the mean pretransfusion hemoglobin was approximately 8.5 g/dl and RBC transfusions were independently associated with an increased mortality. These studies were purely observational and, therefore, despite the finest statistical models indicating that RBC transfusions were independently associated with a higher mortality, it remains possible that this adverse outcome is not due to a harmful effect of RBC transfusion in itself, but merely reflects the fact that transfused patients were sicker to start with. The definitive call is still out, but one mechanism by which RBC transfusion might be harmful now appears less likely; namely, storage lesion. In the CRIT study, mortality was not increased in patients receiving 'old' RBCs (>14 days stored) versus 'fresh' RBCs. The effect of leukoreduction could not be assessed since mainly nonleukoreduced RBCs were transfused. The evidence is mounting, however, that RBC transfusions are efficacious only when oxygen delivery is compromised. What can be done to diminish the use of RBC transfusions, its costs and side effects in intensive care medicine? There are two important options available today: decreasing blood loss for diagnostic purposes using pediatric sampling tubes, and establishing restrictive multidisciplinary transfusion guidelines and implementing them in daily clinical practice.